Danfoss Axial Piston 90 Service guide

Series 90

Axial Piston

Pumps and Motors

Service Manual

Series 90	Introduction

Introduction

Use of this Manual

This manual includes information for the normal operation, maintenance, and servicing of the Series 90 family of hydrostatic pumps and motors.

The manual also includes the description of the units and their individual components, troubleshooting information, adjustment instructions, and minor repair procedures. Unit warranty obligations should not be affected if maintenance, adjustment, and minor repairs are performed according to the procedures described in this manual.

Many service and adjustment activities can be performed without removing the unit from the vehicle or machine. However, adequate access to the unit must be available, and the unit must be thoroughly cleaned before beginning maintenance, adjustment, or repair activities.

Since dirt and contamination are the greatest enemies of any type of hydraulic equipment, cleanliness requirements must be strictly adhered to. This is especially important when changing the system filter and during adjustment and repair activities.

For further information refer to Series 90 Technical Information. For information about fluid requirements refer to SAUER-SUNDSTRAND BLN 9887 or SDF (Id No. 697581).

A worldwide network of SAUER-SUNDSTRAND Authorized Service Centers is available should repairs be needed. Contact any SAUER-SUNDSTRAND Authorized Service Center for details. A list of all Service Centers can be found in bulletin BLN-2-400527, or in brochure SAW (Ident. No. 698266).

Safety Precautions

Observe the following safety precautions when using and servicing hydrostatic products.

Loss of Hydrostatic Braking Ability

WARNING

The loss of hydrostatic drive line power in any mode of operation (e.g., forward, reverse, or "neutral" mode) may cause the loss of hydrostatic braking capacity. A braking system, redundant to the hydrostatic transmission must, therefore, be provided which is adequate to stop and hold the system should the condition develop.

S000 001E

Disable Work Function

WARNING

Certain service procedures may require the vehicle/machine to be disabled (wheels raised off the ground, work function disconnected, etc.) while performing them in order to prevent injury to the technician and bystanders.

S000 005E

Fluid under High Pressure

WARNING

Use caution when dealing with hydraulic fluid under pressure. Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious injury. This fluid may also be hot enough to burn. Serious infection or reactions can develop if proper medical treatment is not administered immediately.

S000 003E

Flammable Cleaning Solvents

WARNING

Some cleaning solvents are flammable. To avoid possible fire, do not use cleaning solvents in an area where a source of ignition may be present.

S000 004E

Copyright 1987-1998, SAUER-SUNDSTRAND GmbH & Co. All rights reserved. Contents subject to change.

S90MVCTCD

S90PVMFCD

2

Series 90	Contents
Contents
Introduction .........................................................................................................................................................................	2
Use of this Manual ........................................................................................................................................................................................	2
Safety Precautions ........................................................................................................................................................................................	2
Functional Description .......................................................................................................................................................	5
General Description and Cross Sectional Views .........................................................................................................................................	5
Variable Displacement Pumps ................................................................................................................................................................	5
Fixed Displacement Motor .....................................................................................................................................................................	5
Variable Displacement Motor ..................................................................................................................................................................	6
The System Circuit .......................................................................................................................................................................................	7
The Basic Closed Circuit ........................................................................................................................................................................	7
Case Drain and Heat Exchanger ...........................................................................................................................................................	7
Common Features of Pumps and Motors ....................................................................................................................................................	8
End Caps and Shafts .............................................................................................................................................................................	8
Speed Sensors .......................................................................................................................................................................................	8
Pump Features .............................................................................................................................................................................................	9
Charge Pump ..........................................................................................................................................................................................	9
Charge Relief Valve .................................................................................................................................................................................	9
Multi-Function Valves ..............................................................................................................................................................................	9
Pressure Limiter and High Pressure Relief Valves .......................................................................................................................	10
System Check Valves ....................................................................................................................................................................	10
Bypass Valves ................................................................................................................................................................................	10
Displacement Limiters ..........................................................................................................................................................................	11
Auxiliary Mounting Pads .......................................................................................................................................................................	11
Filtration Options ...................................................................................................................................................................................	11
Pressure Override (POR) - 180 Frame Size Only .............................................................................................................................	12
Pump Control Options ..........................................................................................................................................................................	13
Manual Displacement Control (MDC) ...........................................................................................................................................	13
Hydraulic Displacement Control (HDC) ........................................................................................................................................	13
Electric Displacement Control (EDC) ............................................................................................................................................	14
Automotive Control (FBA II B) .......................................................................................................................................................	14
3-Position (FNR) Electric Control ..................................................................................................................................................	14
Motor Features ...........................................................................................................................................................................................	15
Motor Loop Flushing Valve and Charge Relief Valve ...........................................................................................................................	15
Variable Motor Displacement Limiters ..................................................................................................................................................	15
Variable Motor Controls ........................................................................................................................................................................	16
Hydraulic 2-Position Control ..........................................................................................................................................................	16
Electric 2-Position Control ..............................................................................................................................................................	16
Technical Specifications ..................................................................................................................................................	17
General Specifications ................................................................................................................................................................................	17
Circuit Diagrams .........................................................................................................................................................................................	17
Hydraulic Parameters .................................................................................................................................................................................	18
Size Specific Data .......................................................................................................................................................................................	19
Pressure Measurement ...................................................................................................................................................	20
Required Tools ............................................................................................................................................................................................	20
Port Locations and Pressure Gauge Installation .......................................................................................................................................	20
Variable Pump .......................................................................................................................................................................................	20
Fixed Motor ...........................................................................................................................................................................................	23
Variable Motor .......................................................................................................................................................................................	24
Initial Start-Up Procedure ................................................................................................................................................	25
Fluid and Filter Maintenance ...........................................................................................................................................	26
Troubleshooting ................................................................................................................................................................	27
"NEUTRAL" Difficult or Impossible to Find .................................................................................................................................................	27
System Operating Hot ................................................................................................................................................................................	27
Transmission Operates Normally in One Direction Only ..........................................................................................................................	28
System Will Not Operate in Either Direction ..............................................................................................................................................	28
Low Motor Output Torque ...........................................................................................................................................................................	29
Improper Motor Output Speed ....................................................................................................................................................................	29
Excessive Noise and/or Vibration ..............................................................................................................................................................	30
System Response is Sluggish ....................................................................................................................................................................	30

3

Series 90	Contents
Inspections and Adjustments .........................................................................................................................................	31
Pump Adjustments ......................................................................................................................................................................................	31
Charge Pressure Relief Valve Adjustment ...........................................................................................................................................	31
Multi-Function Valve Pressure Adjustment ..........................................................................................................................................	33
Engaging the Bypass Function ............................................................................................................................................................	35
Pressure Override (POR) Valve Pressure Adjustment (Option for 180 Frame Size) .......................................................................	36
Displacement Limiter Adjustment .........................................................................................................................................................	37
Pump Control Adjustments .........................................................................................................................................................................	38
Standard Manual Displacement Control (MDC) Adjustment ..............................................................................................................	38
Non-Linear Manual Displacement Control (MDC) ..............................................................................................................................	39
MDC Neutral Start Switch (NSS) Adjustments ....................................................................................................................................	40
Hydraulic Displacement Control (HDC) and Electric Displacement Control (EDC) Adjustment .......................................................	46
Motor Adjustments ......................................................................................................................................................................................	48
Charge Relief Valve Adjustment ...........................................................................................................................................................	48
Displacement Limiter Adjustment (MV) ................................................................................................................................................	49
Displacement Control Adjustments ......................................................................................................................................................	49
Speed Sensor Adjustment ..........................................................................................................................................................................	50
Minor Repair Instructions ................................................................................................................................................	51
Pump and Motor Minor Repair ....................................................................................................................................................................	53
Pump / Fitting Torques ..........................................................................................................................................................................	53
Shaft Seal and Shaft Replacement ......................................................................................................................................................	54
Pump Minor Repairs ...................................................................................................................................................................................	56
Multi-Function Valve Cartridges ...........................................................................................................................................................	56
Pressure Override Valve (Option for 180 Frame Size) .......................................................................................................................	57
Charge Relief Valve ...............................................................................................................................................................................	57
Charge Pump - Remove ......................................................................................................................................................................	58
Installing the Charge Pump ..................................................................................................................................................................	60
Auxiliary Pad Installation .......................................................................................................................................................................	62
Auxiliary Pad Conversion .....................................................................................................................................................................	63
Filtration Options ...................................................................................................................................................................................	64
Pump controls .......................................................................................................................................................................................	65
Cover Plate .....................................................................................................................................................................................	65
Manual Displacement Control (MDC) ...........................................................................................................................................	66
Solenoid Override Valve for MDC ..................................................................................................................................................	67
Solenoid Override Valve for MDC with Pressure Released Brake ..............................................................................................	67
Hydraulic and Electric Displacement Controls .............................................................................................................................	68
Pressure Control Pilot (PCP) for Electric Displacement Control ..................................................................................................	68
3-Position (FNR) Electric Control ..................................................................................................................................................	69
Displacement Control Components ...............................................................................................................................................	69
Minor Repair - Motor ...................................................................................................................................................................................	71
Loop Flushing and Charge Relief Valves .............................................................................................................................................	71
Variable Motor Displacement Limiters ..................................................................................................................................................	73
Variable Motor Controls ...............................................................................................................................................................................	74
Electrohydraulic 2-Position Control (Types NA, NB, NC, and ND) .....................................................................................................	74
Hydraulic 2-Position Control (Type PT) ...............................................................................................................................................	74
Control Plugs ........................................................................................................................................................................................	74
Variable Motor Control Orifices ............................................................................................................................................................	75
Speed Sensor ..............................................................................................................................................................................................	77
Exploded View Parts Drawings / Parts Lists ..................................................................................................................	78
Variable Pumps ...........................................................................................................................................................................................	78
Minor Repair Parts ................................................................................................................................................................................	78
Parts List ...............................................................................................................................................................................................	79
Variable Pump Controls ........................................................................................................................................................................	80
Control Parts List ..................................................................................................................................................................................	81
Filter and Options .................................................................................................................................................................................	82
Parts List Filter and Options .................................................................................................................................................................	83
Name Plates .........................................................................................................................................................................................	83
Fixed Motor .................................................................................................................................................................................................	84
Minor Repair Parts ................................................................................................................................................................................	84
Parts List ...............................................................................................................................................................................................	85
Name Plates .........................................................................................................................................................................................	85
Variable Motor ..............................................................................................................................................................................................	86
Minor Repair Parts ................................................................................................................................................................................	86
Parts List ...............................................................................................................................................................................................	87
Name Plate ............................................................................................................................................................................................	87

4

Series 90	Functional Description

Functional Description

This section describes the operation of pumps, motors, and their various serviceable features. It is a useful reference for readers unfamiliar with the functioning of a specific system.

General Description and Cross Sectional Views

Variable Displacement Pumps

The Variable Displacement Pump (PV) is designed to convert an input torque into hydraulic power. The input shaft turns the pump cylinder which contains a ring of pistons. The pistons run against a tilted plate, called the swashplate. This causes the pistons to compress the hydraulic fluid which imparts the input energy into the hydraulic fluid. The high pressure fluid is then ported out to provide power to a remote function.

The swashplate angle can be varied by the control piston. Altering the swashplate angle varies the displacement of fluid in a given revolution of the input shaft.

F000 539

Series 90 Variable Displacement Pump (PV)

Slider Block

Servo Arm

Servo Valve

Cradle Hold Down

Servo Piston

Feed Back

Cradle Bearing

Cradle

Cradle Leveler

Cradle Guide

Charge Pump

P001 413E

Series 90 PV Cross Section

Fixed Displacement Motor

The Fixed Displacement Motor (MF) is designed to convert an input of hydraulic power into an output torque. It operates in the reverse manner of the pump. The high pressure hydraulic fluid enters through the input port. The fluid pressure builds behind the pistons causing them to move down the swashplate (the path of least resistance). As the piston returns up the swashplate again, the fluid is allowed to exit through the exit port. The spinning pistons are housed in a cylinder which is connected to the output shaft. The output torque can be applied to a mechanical function.

90000347

Series 90 Fixed Displacement Motor (MF)

5

Series 90

Loop Flushing Valve

Valve Plate Piston

Roller Bearing

Output Shaft

Fixed Swashplate

End Cap

Cylinder Block

90000190E

Series 90 MF Cross Section

90000348

Series 90 Variable Displacement Motor (MV)

Valve Plate Piston

End Cap

Roller Bearing

Output Shaft

"A"

"A"

Cradle Swashplate

Cylinder Block

Electric 2-Position Control (optional)

Functional Description

In the Fixed Displacement Motor the "swashplate" is fixed, so any variation in motor speed and torque must be made by the input mechanism, i.e. the pump.

Variable Displacement Motor

The Variable Displacement Motor (MV) operates in the same manner as the fixed motor. However, its swashplate is not fixed; it can be switched between minimum and maximum angle to amplify torque or speed like the Variable Displacement Pump.

Minimum Angle

Control Piston

Cradle Swashplate

Partial Section "A-A"

Cradle Swashplate in Full

Displacement Position

Maximum Angle

Control Piston

90000234E

Series 90 MV Cross Section

6

Series 90	Functional Description

The System Circuit

				System loop (low pressure)
Control Handle	Displacement Control Valve			Case drain fluid
		Heat Exchanger		System loop (high pressure)
		Bypass Valve
	Orificed		Reservoir	Control fluid
	Check Valve			Vacuum Gauge
				Suction line
		Heat Exchanger
			Charge Pressure	Purge Relief Valve
		Multi-Function	Relief Valve
Variable	Servo Control	Valve		Fixed Displacement
	Cylinder
Displacement				Motor
Pump
			to Pump
			Case
		Servo Pres.
		Relief Valve
			Charge Pump
Input				Output Shaft
Shaft

Multi-Function Valve	Motor Swashplate

Pump Swashplate	Servo Control

Cylinder	Loop Flushing Valve
Pump	Fixed Motor

90000800E

Circuit Diagram for Series 90 PV and 90 MF

The Basic Closed Circuit

The main ports of the pump are connected by hydraulic lines to the main ports of the motor. Fluid flows, in either direction, from the pump to the motor then back to the pump in this closed circuit. Either of the hydraulic lines can be under high pressure. In pumping mode the position of the pump swashplate determines which line is high pressure as well as the direction of fluid flow.

Case Drain and Heat Exchanger

The pump and motor require case drain lines to remove hot fluid from the system. The motor should be drained from its topmost drain port to ensure the case remains full of fluid. The motor case drain can then be connected to the lower drain port on the pump housing and out the top most port. A heat exchanger, with a bypass valve, is required to cool the case drain fluid before it returns to the reservoir.

Reservoir

Input

PV

MF

Output

Flow (Bi-directional)

Case Drain Line

90000803E

Basic Closed Circuit

7

Series 90	Functional Description

Common Features of Pumps and Motors

End Caps and Shafts

Series 90 pumps and motors can be supplied with a variety of end caps and shafts to allow for almost any configuration. For pumps, end caps are available with system ports on either side ("side ports") or both ports on one side ("twin ports"). Motors have end caps with ports on the face of the end cap ("axial ports") or both ports on one side ("twin ports"). See the Series 90 Technical Information manuals (BLN-10029 and BLN-10030) or the Series 90 Price Book (BLN-2-40588) for information on available options.

Removing the end cap will void the warranty on a

Series 90 pump or motor.

Speed Sensors

An optional speed sensor can be installed on Series 90 pumps and motors to provide unit speed information. The sensor reads a magnetic ring wrapped about the unit's cylinder. See the corresponding Section to locate, install and adjust the sensor.

90000810

Speed Sensor

8

Series 90	Functional Description

Pump Features

Charge Pump

The charge pump is necessary to supply cool fluid to the system, to maintain positive pressure in the main system loop, to provide pressure to operate the control system, and to make up for internal leakage. Charge pressure must be at its specified pressure under all conditions of driving and braking to prevent damage to the transmission.

The charge pump is a fixed-displacement, gerotor type pump installed in the variable displacement pump and driven off the main pump shaft. Charge pressure is limited by a relief valve.

The standard charge pump will be satisfactory for most applications. However, if the charge pump sizes available for the given main pump size are not adequate, a gear pump may be mounted to the auxiliary mounting pad and supply the required additional charge flow.

Charge Relief Valve

The charge relief valve on the pump serves to maintain charge pressure at a designated level. A direct-acting poppet valve relieves charge pressure whenever it surpasses a certain level. This level is nominally set referencing case pressure at 1500 rpm. This nominal setting assumes the pump is in neutral (zero flow); in forward or reverse charge pressure will be lower. The charge relief valve setting is specified on the model code of the pump.

		90000243
		PV with Charge Pump
	Case
	Drain	Charge Relief Valve
	Line
		System
		Check
		Valves

Input

PV

PF

Charge

Pump

Inlet Filter

Tank

90000804E

Pump Charge System

Multi-Function Valves

The multi-function valve incorporates the system check valve,

the pressure limiter valve,

the high pressure relief valve and the bypass valve

in a replaceable cartridge.
These functions are described separately. There are two
multi-function valve cartridges in each Series 90 pump to
handle functions in either direction. See corresponding
Sections for adjustments and repairs.
NOTE: Some multi-function valves do not include a	90000243
pressure limiter valve.	Multi-Function Valve

9

Series 90

Pressure Limiter Housing		High Pressure		Check Valve
		Relief / check
Pressure Limiter		Valve Poppet		Poppet
Lock Nut
Pressure Limiter
Adjustment Screw
Bypass			Bypass
Actuator	Pressure Limiter
	Valve Poppet

90000806E

Cross Section of Multi-Function Valve

	To Control
	Multi-Function Valve
Servo Piston	Bypass
	Adjustment
Port "A"

Servo Pres.

Relief Valve

Port "B"

Servo Piston

Charge Pressure

Relief Valve

Multi-Function Valve

90000801E

Circuit Diagram showing Pressure

Control Mechanism

Functional Description

Pressure Limiter and High Pressure Relief Valves

Series 90 pumps are designed with a sequenced pressure limiting system and high pressure relief valves. When the preset pressure is reached, the pressure limiter system acts to rapidly destroke the pump so as to limit the system pressure. For unusually rapid load application, the high pressure relief valve acts to immediately limit system pressure by cross-porting system flow to the low pressure side of the loop. The pressure limiter valve acts as the pilot for the high pressure relief valve spool. The high pressure relief valve is sequenced to operate at approximately 35 bar (500 psi) above the level that initiates the pressure limiter valve.

Both the pressure limiter sensing valves and relief valves are built into the multi-function valves (see above).

NOTE: For some applications, such as dual path vehicles, the pressure limiter function may be defeated so that only the high pressure relief valve function remains.

System Check Valves

The system check valves allow pressurized flow from the charge pump to enter the low pressure side of the loop whenever system pressure dips below a certain level. This is needed as the pump will generally lose system pressure due to leakage and other factors. Since the pump can operate in either direction, two system check valves are used to direct the charge supply into the low pressure lines. The system check valves are poppet valves located in the multi-function valve assembly.

Bypass Valves

The bypass valves ("tow") can be operated when it is desired to move the vehicle or mechanical function when the pump is not running. The valve is opened by manually resetting the valve position.

The bypass valves are built into the multi-function valves.

10

Series 90

Displacement Limiters

All Series 90 pumps are designed for optional mechanical displacement (stroke) limiters. The maximum displacement of the pump can be limited in either direction.

The setting can be set as low as 0° in either direction.

For instructions on adjustment see corresponding Section.

Auxiliary Mounting Pads

Auxiliary mounting pads are available on all Series 90 pumps. SAE A through E mounts are available (availability varies by pump size). This pad is used for mounting auxiliary hydraulic pumps and for mounting additional Series 90 pumps to make tandem pumps. The pads allow for full through-torque capability.

Filtration Options

All Series 90 pumps are available with provisions for either suction or charge pressure filtration (integral or remote mounted) to filter the fluid entering the charge circuit.

Suction Filtration

The suction filter is placed in the circuit between the reservoir and the inlet to the charge pump. When suction filtration is used, a reducer fitting is placed in the charge pressure gauge port (M3). Filtration devices of this type are provided by the user.

Charge Pressure Filtration

The pressure filter may be integrally mounted directly on the pump or a filter may be remotely mounted for ease of servicing.

A 125 m screen, located in the reservoir or the charge inlet line, is recommended when using this filtration option.

Functional Description

90000244

PV with Displacement Limiters

90000242

PV with Auxillary Mounting Pad

90000243

PV with Suction Filtration (No filtration device attached)

90000246	90000247
PV with Integral Charge	PV with Remote Charge
Pump	Pump

11

Series 90

To Control

Multi-Function Valve

Pressure

Override Control Valve Bypass

Adjustment

Port "A"

Shuttle

Valve

Port "B"

Multi-Function Valve	Charge Pressure
	Relief Valve

90000802E

POR-Valve (180 Frame Size only)

Functional Description

Pressure Override (POR) - 180 Frame Size Only

The pressure override valve (POR) modulates the control pressure to the displacement control to maintain a pump displacement which will produce a system pressure level less than or equal to the POR setting. For unusually rapid load application, the high pressure relief valve function of the multifunction valves is available to also limit the pressure level.

The pressure override consists of a three-way normally open valve which operates in series with the pump displacement control. Control supply pressure is normally ported through the pressure override valve to the displacement control valve for controlling the pump's displacement. If the system demands a pressure above the override setting, the POR valve will override the control by reducing the control pressure supplied to the displacement control. As the control pressure reduces, the internal forces tending to rotate the swashplate overcome the force of the servo pistons and allow the pump's displacement to decrease.

12

Series 90	Functional Description

Pump Control Options

Manual Displacement Control (MDC)

The manual displacement control converts a mechanical input signal to a hydraulic signal using a springcentered fourway servo valve. This valve ports hydraulic pressure to either side of a dual-acting servo piston. The servo piston rotates the cradle swashplate through an angular rotation of ±17°, thus varying the pump’s displacement from full displacement in one direction to full displacement in the opposite direction.

The MDC is designed so the angular position of the pump swashplate is proportional to the rotation of the control input shaft.

Non-Linear MDC

The non-linear manual displacement control operates in the same manner as the regular MDC except that it is designed so the change in the angular position of the pump swashplate progressively increases as the control input shaft is rotated toward its maximum displacement position.

Solenoid Override Valve for MDC

A solenoid override valve option (not shown here) is available for MDC. This safety feature will return the swashplate to zero displacement position when activated. The valve may be set in either a normally open or normally closed mode.

Neutral Start Switch (NSS)

The neutral start switch is an optional feature available with MDC. When connected properly with the vehicle’s electrical system, the neutral start switch ensures that the prime mover can be started only when the control is in a neutral position.

90000237

PV with Manual Displacement Control

90000239

	Hydraulic Displacement Control (HDC)	PV with Manual Displacement Control and
		Neutral Start Switch

The hydraulic displacement control uses a hydraulic input signal to operate a spring-centered four-way servo valve. This valve ports hydraulic pressure to either side of a dual-acting servo piston. The servo piston rotates the cradle swashplate through an angular rotation of ±17°, thus varying the pump’s displacement from full displacement in one direction to full displacement in the opposite direction. The HDC is designed so the angular position of the pump swashplate is proportional to input pressure.

90000240

PV with Hydraulic Displacement Control

13

Series 90

90000241

PV with Electric Displacement Control

90000354

PV with 3-Position (FNR) Electric Control

Functional Description

Electric Displacement Control (EDC)

The electric displacement control is similar to the hydraulic displacement control with the input signal pressure controlled by a pressure control pilot (PCP) valve. The PCP valve converts a DC electrical input signal to a hydraulic signal which operates a springcentered fourway servo valve. This valve ports hydraulic pressure to either side of a dual-acting servo piston. The servo piston rotates the cradle swashplate through an angular rotation of ±17°, thus varying the pump’s displacement from full displacement in one direction to full displacement in the opposite direction. The control is designed so the angular position of the swashplate is proportional to the EDC input.

Automotive Control (FBA II B)

Automotive Control allows a vehicle to be driven in a manner similar to an automobile with an automatic transmission.

The Automotive Control includes a three-position electric control to provide direction control.

3-Position (FNR) Electric Control

This control utilizes a 12 or 24 VDC electrically operated spool valve to port pressure to either side of the pump displacement control piston. Energizing one of the solenoids will cause the pump to go to its maximum displacement in the corresponding direction.

All functions of the three-position (FNR) electric control are preset at the factory.

14

Series 90	Functional Description

Motor Features

Motor Loop Flushing Valve and Charge Relief

Valve

All Series 90 motors are designed to accommodate a loop flushing valve. The loop flushing valve is used in installations which require additional fluid to be removed from the main hydraulic circuit because of transmission cooling requirements, or unusual circuits requiring additional loop flushing to remove excessive contamination in the high pressure circuit.

A shuttle valve and charge relief valve are installed in the motor end cap to provide the loop flushing function. The shuttle valve provides a circuit between the low pressure side of the closed loop and the charge relief valve in the motor end cap.

The motor charge relief valve regulates the charge pressure level only when there is a pressure differential in the main loop. The shuttle valve is spring centered to the closed position so that no high pressure fluid is lost from the circuit when reversing pressures.

For charge relief valve adjustment see corresponding Section.

90000248

Loop Flushing Valve (MF)

Top of Motor

Charge Relief Valve

Loop Flushing Shuttle Valve	End Cap

90000238E

Motor Charge Relief Valve and Loop Flushing

Shuttle Valve

Variable Motor Displacement Limiters

All Series 90 variable motors include mechanical displacement (stroke) limiters. Both the maximum and minimum displacement of the motor can be limited.

The range of the settings is as follows:

		055 MV	075 MV
	Minimum	19 - 40 cm3	26 - 54 cm3
	Displacement	1.2 - 2.4 in3	1.6 - 3.3 in3
	Maximum	65 - 100 %	65 - 100 %
	Displacement
			T002 251E

90000352

MV Maximum Displacement Limiter (Minimum Displacement Limiters on opposite side)

15

Series 90	Functional Description

Variable Motor Controls

Hydraulic 2-Position Control

This control utilizes a hydraulically operated three-way hydraulic valve to port system pressure to either of the motor displacement control pistons. The motor is normally held at its maximum displacement. Supplying pilot hydraulic pressure to the valve will cause the motor to go to its minimum displacement.

90000350

MV with Hydraulic 2-Position Control

Electric 2-Position Control

This control utilizes an electric solenoid operated threeway hydraulic valve to port system pressure to either of the motor displacement control pistons. The motor is normally held at its maximum displacement. Energizing the solenoid will cause the motor to go to its minimum displacement.

90000351

MV with Electric 2-Position Control

16

Series 90	Technical Specifications

Technical Specifications

General Specifications

Design

Variable Pumps and Motors: Axial piston pump of variable displacement, cradle swashplate design.

Fixed Motors: Axial piston motor with fixed displacement, fixed swashplate design.

Type of Mounting (per SAE J744)

SAE flange, Size "B", 2 bolts,

SAE flange, Size "C and E", 4 bolts.

Cartridge flange, 2 bolts (for motor only).

Port Connections

(for details see chapter "Pressure Measurement")

Main pressure ports: SAE flange, Code 62, Remaining ports: SAE straight thread O-ring boss.

Direction of Rotation

Clockwise or counterclockwise (motors are bi-directional)

Recommended Installation Position

Pump installation recommended with control position on the top or side. Consult SAUER-SUNDSTRAND for nonconformance guidelines. The housing must always be filled with hydraulic fluid.

Circuit Diagrams

	M3
X5	A
	M1
M5
M4

L2	M3
A	M1
	Vgmax

B

M2

			L1
		M2
		B	MV with Electrohydraulic 2-Position
L1	S	L2		Control
PV with Charge Pump and Manual
	Displacement Control			L2 M3
			A	M1

B	M2
L1

90000811 MF 90000812 90000813

17

Series 90	Technical Specifications

Hydraulic Parameters

System Pressure Range	bar	psi
Rated Pressure	420	6000
Maximum Pressure	480	6960
		T002 252E

	Charge Pump Inlet Vacuum	bar abs	in Hg
	(on pumps only)
	Minimum Vacuum	0.7	10
	(continuous)
	Minimum Vacuum during
	Cold Start	0.2	25
	(Intermittent)
			T002 253E
	Case Pressure	bar	psi
	Maximum (Continuous)	3	44
	Maximum during Cold Start	5	73
	(Intermittent)
			T002 254E

Temperature Range1)

	°C	[°F]
Minimum	-40	[-40]	intermittent, cold start
Rated	104	[220]
Maximum	115	[240]	intermittent

T002 006E

1)At the hottest point, normally the case drain port.

Viscosity

		mm2/s		[SUS]
Minimum		7	[49]		intermittent
Recommended		12-60	[70-278]
operating range
Maximum		1600	[7500]		intermittent,
					cold start
						T002 010E
Cleanliness Level and βx-Ratio
Required fluid cleanliness				ISO 4406 Class 18/13
level
Recommended βx-ratio				β35-45=75		(β10≥2)
for suction filtration
Recommended βx-ratio				β15-20=75		(β10≥10)
for charge pressure
filtration
Recommended inlet				100 µm-125 µm
screen size for charge
pressure filtration
						T002 007E

Hydraulic Fluid

Refer to SAUER-SUNDSTRAND BLN 9887 or SDF (Id No. 697581). Also refer to publication ATI-E 9101 for information relating to biogradable fluids.

Cleanliness

Refer to SAUER-SUNDSTRAND Publications BLN 9887 or SDF (NO. 697581) and ATI-E 9201.

Refer to Series 90 technical information for definitions.

18

	Series 90						Technical Specifications
	Size Specific Data
	Variable Displacement Pumps
			Dimension	030 PV	042 PV	055 PV	075 PV	100 PV	130 PV	180 PV	250 PV
	Displacement		cm3	30	42	55	75	100	130	180	250
	(maximum)		in3	1.83	2.56	3.35	4.57	6.10	7.93	10.98	15.25
	Minimum Speed		min-1 (rpm)	500	500	500	500	500	500	500	500
	Rated Speed		min-1 (rpm)	4200	4200	3900	3600	3300	3100	2600	2300
	Maximum Speed		min-1 (rpm)	4600	4600	4250	3950	3650	3400	2850	2500
	Maximum attainable Speed		min-1 (rpm)	5000	5000	4700	4300	4000	3700	3150	2750
	at max. Displacement
	Theoretical Torque at		Nm/bar	0.48	0.67	0.88	1.19	1.59	2.07	2.87	3.97
	max. Displacement		lbf•in/1000 psi	290	380	530	730	870	1260	1750	2433
	Weight		kg	28	34	40	49	68	88	136	154
	(only base unit)		lb	62	75	88	108	150	195	300	340
											T002 257E
	Fixed and Variable Displacement Motors
			Einheit	030 MF	042 MF	055 MF	075 MF	100 MF	130 MF	055 MV	075 MV
	Displacement (maximum)		cm3	30	42	55	75	100	130	55	75
			in3	1.83	2.56	3.35	4.57	6.10	7.93	3.35	4.57
	Displacement (minimum)		cm3	--	--	--	--	--	--	19	26
			in3
		at maximum	min-1 (rpm)	4200	4200	3900	3600	3300	3100	3900	3600
	Rated	displacement
	speed	at minimum	min-1 (rpm)	--	--	--	--	--	--	4600	4250
		displacement
		at maximum	min-1 (rpm)	4600	4600	4250	3950	3650	3400	4250	3950
	Maximum	displacement
	speed	at minimum	min-1 (rpm)	--	--	--	--	--	--	5100	4700
		displacement
	Max. attainable speed at		min-1 (rpm)	5000	5000	4700	4300	4000	3700	4700	4300
	max. displacement
	Theoretical torque at max.		Nm/bar	0.48	0.67	0.88	1.19	1.59	2.07	0.88	1.19
	displacement		lbf•in/1000 psi	290	380	530	730	970	1260	530	730
	Maximum flow ar max.		l/min	138	193	234	296	365	442	234	296
	displacement		gal/min	36.5	51	62	78	96	117	62	78
	Max. corner power		kW	111	155	187	237	292	354	224	282
			hp	149	208	251	318	392	475	300	378
	Weight		kg	11	15	22	26	34	45	39	44
	SAE-Flange		lb	24	34	49	57	74	99	86	98
	Weight		kg	--	21	26	33	--	--	40	46
	Cartridge Motor		lb		46	57	72			88	101
											T002 258E

Refer to Series 90 technical information for definitions.

19

Series 90	Pressure Measurement

Pressure Measurement

Required Tools

The service procedures described in this manual for Series 90 pumps and motors can be performed using common mechanic's tools. Special tools, if required are shown.

Pressure gauges should be calibrated frequently to ensure accuracy. Snubbers are recommended to protect pressure gauges.

Port Locations and Pressure Gauge Installation

The following sections list the ports for each type of hydraulic unit. The recommended pressure gauge and fitting are also specified.

Variable Pump

Outline drawings showing port locations follow the tables below.

			Gauge Size
	Port	Function	and
			Fitting
	M1	System Pressure	1000 bar or 10 000 psi
		Port "A"	9/16-18 O-ring
	M2	System Pressure	1000 bar or 10 000 psi
		Port "B"	9/16-18 O-ring fitting
	M3	Charge Pressure	50 bar or 1000 psi
	(M6)		9/16-18 O-ring
	M4	Servo Pressure	50 bar or 1000 psi
	M5		9/16-18 O-ring

T002 259E

				Gauge Size
Port	Function			and
				Fitting
L1	Case Pressure		10 bar or 100 psi
L2
		030		7/8-14 O-ring
		042
		055
		075		1-1/16-12 O-ring
		100
		130		1-5/16-12 O-ring
		180		1-5/8-12 O-ring
		250
			50 bar or 1000 psi
X1	HDC / EDC			7/16-20 O-ring
X2	Control Pressure			or
				9/16-18 O-ring
X3	External Control		50 bar or 1000 psi
	Pressure			9/16-18 O-ring
S	Charge Pump Inlet	Vacuum Gauge, Tee into
				Inlet Line
		030		1-1/16-12 O-ring
		042
		055		1-5/16-12 O-ring
		075
		100
		130		1-5/8-12 O-ring
		180
		250		1-1/2 SAE-Split
				Flange
				T002 260E

20

Series 90	Pressure Measurement

Servo / Displacement

Cylinder Pressure

Gauge Port M4

Case Drain

Port L1

System Pressure

Port B

Servo / Displacement

Cylinder Pressure

Gauge Port M5

Top View

90000814E

System Pressure

	System Pressure	Port B	External Control Pressure
			Supply Port X3
	Gauge Port M2
			Speed Sensor
	Charge Inlet Pressure

System Pressure

Gauge Port M1

Carge Pump
Inlet Port S	System Pressure	Case Drain Port L2	Charge Pressure
			Gauge Port M3
	Port A
	Left Side View		Right Side View

90000815E

90000816E

PV with Side Port End Cap and Manual Displacement Control

21

Series 90	Pressure Measurement

		Servo / Displacement
		Cylinder Pressure
	System Pressure	Gauge Port M4
		Case Drain
	Gauge Port M2
		Port L1

System Pressure

Port B

Charge Pump Inlet

Port S

System Pressure

Port A

System Pressure		Servo / Displacement
Gauge Port M1	Case Drain Port L2	Cylinder Pressure
		Gauge Port M5
	Left Side View	Top View

90000819E

90000820E

PV with Twin Port End Cap and Manual Displacement Control

Charge Pressure Gauge Port M6 (before the filter)

Port E (from filter)

Port D (to filter)

	Charge Pressure
	Gauge Port M3	Charge Pressure
	(after the filter)
		Gauge Port M3
	Rear View	(after the filter)
		Rear View

90000817E

90000818E

PV with Side Port End Cap and Remote Pressure Filtration

PV with Side Port End Cap and Integral Pressure Filtration

22

Series 90	Pressure Measurement

Fixed Motor

			Gauge Size
	Port	Function	and
			Fitting
	M1	System Pressure	1000 bar or 10 000 psi
		Port "A"	9/16-18 O-ring
	M2	System Pressure	1000 bar or 10 000 psi
		Port "B"	9/16-18 O-ring
	M3	Charge Pressure	50 bar or 1000 psi
			9/16-18 O-ring
			T002 261E

				Gauge Size
Port	Function			and
				Fitting
L1	Case Pressure)		10 bar or 500 psi
L2
		030
		042		7/8-14 O-ring
		055
		075
		100		1-1/16-12 O-ring
		130
				T002 262E

	System Pressure
	Gauge Port M1
Charge Pressure	System Pressure	Case Drain Port L1
Gauge Port M3	Gauge Port M2

		System Pressure Port B		Speed Sensor
	System Pressure Port A		Case Drain Port L2
	Rear View		Left Side View
		MF with SAE Flange
		System Pressure
	Charge Pressure	Gauge Port M1		Case Drain Port L1
		System Pressure
	Gauge Port M3	Gauge Port M2

System Pressure Port B

System Pressure Port A

Speed Sensor

Case Drain Port L2

Rear View

Left Side View

90000821E

MF with Cartridge Flange

23

Series 90	Pressure Measurement

Variable Motor

			Gauge Size
	Port	Function	and
			Fitting
	M1	Systempressure	1000 bar or 10 000 psi
		Port "A"	9/16-18 O-ring
	M2	Systempressure	1000 bar or 10 000 psi
		Port "B"	9/16-18 O-ring
	M3	Charge Pressure	50 bar or 1000 psi
			9/16-18 O-ring
			T002 263E

System Pressure

Gauge Port M2

Control Pressure

Port X1

(Hydraulic 2-Position Control)

System Pressure Port B

			Gauge Size
	Port	Function	and
			Fitting
		Control Cylinbder	1000 bar or 10 000 psi
	M4	Pressure "Minimum
			7/16-20 O-ring
		Displacement"
		Control Cylinbder	1000 bar or 10 000 psi
	M5	Pressure"Maximum
			7/16-20 O-ring
		Displacement"
	L1	Case Pressure	10 bar or 500 psi
	L2		1-1/16-12 O-ring

T002 264E

Displacement Control

Cylinder Pressure

Gauge Port M4

Min. Displacement

Displacement Control Cylinder Pressure Gauge Port M5

Max. Displacement (Earlier Production - Not available as gauge port with servo orifices)

Displacement Control

Cylinder Pressure

Gauge Port M5

Max. Displacement

(Newer Production)

Left Side View

MV with Cartridge Flange and Hydraulic 2-Position Control (SAE Flange Version Similar)

Case Drain Port L1

System Pressure

Gauge Port M1

charge Pressure Gauge Port M3

(Same position as in MF)

Speed Sensor

System Pressure Port A

Case Drain Port L2

Right Side View

90000823E

MV with SAE Flange (Cartridge Flange Version Similar)

24

Series 90	Initial Start-Up Procedure

Initial Start-Up Procedure

The following start-up procedure should always be followed when starting-up a new Series 90 installation or when restarting an installation in which either the pump or motor had been removed.

WARNING

The following procedure may require the vehicle/ machine to be disabled (wheels raised off the ground, work function disconnected, etc.) while performing the procedure in order to prevent injury to the technician and bystanders. Take necessary safety precautions before moving the vehicle/machine.

S000 007E

Prior to installing the pump and/or motor, inspect the units for damage incurred during shipping and handling. Make certain all system components (reservoir, hoses, valves, fittings, heat exchanger, etc.) are clean prior to filling with fluid.

Fill the reservoir with recommended hydraulic fluid. This fluid should be passed through a 10 micron (nominal, no bypass) filter prior to entering the reservoir. The use of contaminated fluid will cause damage to the components, which may result in unexpected vehicle/machine movement. See the publications BLN-9887 and SDF 697581 for further related information.

The inlet line leading from the reservoir to the pump must be filled prior to start-up. Check inlet line for properly tightened fittings and make sure it is free of restrictions and air leaks.

Be certain to fill the pump and/or motor housing with clean hydraulic fluid prior to start up.

Fill the housing by pouring filtered oil into the upper case drain port.

Install a 50 bar (or 1000 psi) pressure gauge in the charge pressure gauge port to monitor the charge pressure during start-up.

It is recommended that the external control input signal (linkage for MDC, hydraulic lines for HDC, or electrical

connections for EDC) be disconnected at the pump control until after initial start-up. This will ensure that the pump remains in its neutral position.

WARNING

Do not start prime mover unless pump is in neutral position (0° swashplate angle). Take precautions to prevent machine movement in case pump is actuated during initial start up.

S000 008E

“Jog” or slowly rotate prime mover until charge pressure starts to rise. Start the prime mover and run at the lowest possible RPM until charge pressure has been established. Excess air may be bled from the high pressure lines through the high pressure system gauge port.

Once charge pressure has been established, increase speed to normal operating RPM. Charge pressure should be as indicated in the pump model code. If charge pressure is inadequate, shut down and determine cause for improper pressure. Refer to Troubleshooting.

WARNING

Take necessary precautions that the motor shaft remains stationary during the adjustment procedure.

S000 010E

Shut down the prime mover and connect the external control input signal. Also reconnect the machine function if disconnected earlier. Start the prime mover, checking to be certain the pump remains in neutral. With the prime mover at normal operating speed, slowly check for forward and reverse machine operation.

Charge pressure may slightly decrease during forward or reverse operation. Continue to cycle slowly between forward and reverse for at least five minutes.

Shut down prime mover, remove gauges, and plug ports. Check reservoir level and add filtered fluid if needed.

The transmission is now ready for operation.

25

Series 90	Fluid and Filter Maintenance

Fluid and Filter Maintenance

Mano-

Vacuummeter

	Hydraulic fluid reservoir
	Filter
	Charge pump
	Adjustable
to low	Charge pressure relief valve
pressure
side and	To pump case
control

P000 797E

Suction Filtration Schematic

Screen

Hydraulic fluid reservoir

	Adjustable
	Charge pressure
	relief valve
	Charge pump
to low	To pump case
pressure
side and
control

Filter

P000 798E

Charge Pressure Filtration Schematic

(Partial flow)

To ensure optimum service life of Series 90 products, regular maintenance of the fluid and filter must be performed. Contaminated fluid is the main cause of unit failure. Care should be taken to maintain fluid cleanliness while performing any service procedure.

Check the reservoir daily for proper fluid level, the presence of water (noted by a cloudy to milky appearance, or free water in bottom of reservoir), and rancid fluid odor (indicating excessive heat). If either of these conditions occur, change the fluid and filter immediately.

It is recommended that the fluid and filter be changed per the vehicle/machine manufacturer’s recommendations or at the following intervals:

First change

500 operating hours after start up

second and subsequent changes

every 2000 operating hours or once a year.

This recommendation applies for the most applications. High temperatures and pressures will result in accelerated fluid aging and an earlier fluid change may be required. At lower fluid loads longer change intervalls are possible. Therefore we suggest to check the fluid with the manufacturer for suitability. This should be done at latest half way between fluid changes.

It may be necessary to change the fluid more frequently than the above intervals if the fluid becomes contaminated with foreign matter (dirt, water, grease, etc.) or if the fluid has been subjected to temperature levels greater than the recommended maximum. Never reuse fluid.

The filter should be changed whenever the fluid is changed or whenever the filter indicator shows that it is necessary to change the filter.

Cleanliness Level and βx-Ratio

	Required fluid cleanliness	ISO 4406 Class 18/13
	level
	Recommended βx-ratio	β35-45=75	(β10≥2)
	for suction filtration
	Recommended βx-ratio	β15-20=75	(β10≥10)
	for charge pressure
	filtration
	Recommended inlet	100 µm-125 µm
	screen size for charge
	pressure filtration
			T002 007E

26

Series 90	Toubleshooting

Troubleshooting

This section provides general steps to follow if certain undesirable system conditions are observed. Follow the steps in a section until the problem is solved. Some of the items will be system specific. For areas covered in this manual, a section is referenced. Always observe the safety precautions listed in the section "Introduction" and related to your specific equipment.

"NEUTRAL" Difficult or Impossible to Find

	Check	Description	Action
1.	Input to pump control.	Input to control module is operating	Check control input and repair or re-
		improperly.	place as necessary.
2.	Pump displacement control.	Control linkages are not secure, control	Adjust, repair, or replace control mod-
		orifices are blocked, etc.	ule as necessary.

If the above actions do not remedy the problem contact a SAUER-SUNDSTRAND Authorized Service Center.

System Operating Hot

Check

Description

Action

1.	Oil level in reservoir.	Insufficient hydraulic fluid will not meet
		cooling demands of system.
2.	Heat exchanger.	Heat exchanger not sufficiently cooling
		the system.
3.	Charge pressure.	Low charge pressure will overwork sys-
		tem.
4.	Charge pump inlet vacuum.	High inlet vacuum will overwork sys-
		tem. A dirty filter will increase the inlet
		vacuum. Inadequate line size will re-
		strict flow.

Fill reservoir to proper level.

Check air flow and input air temperature for heat exchanger. Clean, repair or replace heat exchanger.

Measure charge pressure. Inspect and adjust or replace charge relief valve. Or repair leaky charge pump.

Check charge inlet vacuum. If high, inspect inlet filter and replace as necessary. Check for adequate line size, length or other restrictions.

5.System relief pressure settings.

6.For internal leakage in motor.

If the system relief settings are too low, the relief valves will be overworked.

Verify settings of pressure limiters and high pressure relief valves and adjust or replace multi-function valves as necessary.

	Leakage will reduce low side system	Monitor motor case flow without loop
	pressure and overwork the system.	flushing in the circuit (use defeat spool).
		If flow is excessive, replace motor.
7. System pressure.	High system pressure will overheat	Measure system pressure. If pressure
	system.	is high reduce loads.

If the above actions do not remedy the problem contact a SAUER-SUNDSTRAND Authorized Service Center.

27