Danfoss Open Circuit Axial Piston Pumps Service guide

Service Manual

Open Circuit Axial Piston Pumps

Series 45 Frame K and L

www.danfoss.com

Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Revision history	Table of revisions
	Date	Changed	Rev
	April 2021	Changed document number from 'AX00000040' and '520L0532' to 'AX152886485004' and	0504
		corrected electric control drawing
	August 2016	Updated tables and Adjustments chapter	0401
	April 2016	minor deits - Engineering Tomorrow	0301
	October 2014	updates for DITA CMS	BB
	August 2014	Danfoss layout	BA

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Service Manual
Series 45 Frame K and L Open Circuit Axial Piston Pumps
Contents
Introduction
Using this manual.............................................................................................................................................................................	5
Safety precautions............................................................................................................................................................................	5
Unintended machine movement..........................................................................................................................................	5
Flammable cleaning solvents.................................................................................................................................................	5
Fluid under pressure..................................................................................................................................................................	5
Personal safety.............................................................................................................................................................................	5
Symbols used in Danfoss literature............................................................................................................................................	6
General description.........................................................................................................................................................................	6
The system circuit.............................................................................................................................................................................	7
Technical specifications
General specifications.....................................................................................................................................................................	9
Type of mounting.......................................................................................................................................................................	9
Auxiliary mounting pad options............................................................................................................................................	9
Control options............................................................................................................................................................................	9
Port options...................................................................................................................................................................................	9
Direction of rotation...................................................................................................................................................................	9
Installation position....................................................................................................................................................................	9
Technical specifications............................................................................................................................................................	9
Hydraulic parameters...................................................................................................................................................................	10
Inlet pressure..............................................................................................................................................................................	10
Pressure compensator valve setting..................................................................................................................................	10
Case pressure.............................................................................................................................................................................	10
Hydraulic fluid ...........................................................................................................................................................................	10
Temperature range (1)............................................................................................................................................................	10
Fluid viscosity.............................................................................................................................................................................	10
Filtration ......................................................................................................................................................................................	10
Features
Displacement limiter.....................................................................................................................................................................	11
Auxiliary mounting pads.............................................................................................................................................................	11
Input shafts.......................................................................................................................................................................................	11
Control options...............................................................................................................................................................................	11
Operation.....................................................................................................................................................................................	11
Electronic Controls...................................................................................................................................................................	14
Pressure measurement
Required tools.................................................................................................................................................................................	15
Port locations and gauge installation.....................................................................................................................................	15
Initial start-up procedures
General...............................................................................................................................................................................................	16
Start-up procedure........................................................................................................................................................................	16
Fluid and filter maintenance
Recommendations........................................................................................................................................................................	17
Troubleshooting
Excessive noise and/or vibration..............................................................................................................................................	18
Actuator response is sluggish....................................................................................................................................................	18
System operating hot...................................................................................................................................................................	18
Low pump output flow................................................................................................................................................................	19
Pressure or flow instability..........................................................................................................................................................	19
System pressure not reaching PC setting.............................................................................................................................	20
High inlet vacuum..........................................................................................................................................................................	20
Adjustments
PC control..........................................................................................................................................................................................	21
LS control..........................................................................................................................................................................................	22
Displacement limiter.....................................................................................................................................................................	23
Minor repair
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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Contents

Shaft seal replacement.................................................................................................................................................................	25
Auxiliary pads..................................................................................................................................................................................	25
LS and PC Controls.........................................................................................................................................................................	27
Electric Controls..............................................................................................................................................................................	29
Servo Control Orifice.....................................................................................................................................................................	31
Plug and fitting sizes and torques...........................................................................................................................................	31

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Introduction

Using this manual

This manual includes information for the normal operation, maintenance, and service of the Series 45 frame K and L open circuit pumps. The manual includes a 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, follow cleanliness requirements strictly. This is especially important when changing the system filter and when removing hoses or plumbing.

A worldwide network of Danfoss Authorized Service Centers (ASCs) is available should major repairs be needed. Contact any Danfoss ASC for details. A list of all ASCs can be found in bulletin BLN-2-40527, or in brochure SAW (Ident. No. 698266), or you can locate your nearest ASC using the distributor locator at http://www.powersolutions.danfoss.com

Safety precautions

Always consider safety precautions before beginning a service procedure. Protect yourself and others from injury. Take the following general precautions whenever servicing a hydraulic system.

Unintended machine movement

W Warning

Unintended movement of the machine or mechanism may cause injury to the technician or bystanders. To protect against unintended movement, secure the machine or disable / disconnect the mechanism while servicing.

Flammable cleaning solvents

W 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.

Fluid under pressure

W Warning

Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious injury and/or infection. This fluid may also be hot enough to cause burns. Use caution when dealing with hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, gauges, or components. Never use your hand or any other body part to check for leaks in a pressurized line. Seek medical attention immediately if you are cut by hydraulic fluid.

Personal safety

W Warning

Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Introduction

Symbols used in Danfoss literature

WARNING may result in injury

CAUTION may result in damage to product or property

Reusable part

Non-reusable part, use a new part

Non-removable item

Option - either part may exist

Superseded - parts are not interchangeable

Measurement required

Flatness specification

Parallelism specification

External hex head

Internal hex head

Torx head

O-ring boss port

Tip, helpful suggestion

Lubricate with hydraulic fluid

Apply grease / petroleum jelly

Apply locking compound

Inspect for wear or damage

Clean area or part

Be careful not to scratch or damage Note correct orientation

Mark orientation for reinstallation

Torque specification

Press in - press fit

Pull out with tool – press fit

Cover splines with installation sleeve

Pressure measurement/gauge location or specification

The symbols above appear in the illustrations and text of this manual. They are intended to communicate helpful information at the point where it is most useful to the reader. In most instances, the appearance of the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.

General description

Danfoss Series 45 K and L frame open circuit piston pumps convert input torque into hydraulic power. Rotational force is transmitted through the input shaft to the cylinder block. The input shaft is supported by tapered roller bearings at the front and rear of the pump and is splined into the cylinder block . A lipseal at the front end of the pump prevents leakage where the shaft exits the pump housing. The spinning cylinder block contains nine reciprocating pistons. Each piston has a brass slipper connected at one end by a ball joint. The slippers are held to the swashplate by the spring retainer and block spring. The block spring also holds the cylinder block to the valve plate. The reciprocating movement of the pistons occurs as the slippers slide against the inclined swashplate during rotation. Via the valve plate, one half of the cylinder block is connected to pump inlet and the other half to pump outlet. As each piston cycles in and out of its bore, fluid is drawn from the inlet and displaced to the outlet thereby imparting power into the system circuit. A small amount of fluid is allowed to leak from the cylinder block / valve plate and slipper / swashplate interfaces for lubrication and cooling. Case drain ports are provided to return this fluid to the reservoir.

The volume of fluid displaced into the system circuit is controlled by the angle of the swashplate. The swashplate is forced into an inclined position (into stroke) by the bias spring. The servo piston opposes the action of the bias spring forcing the swashplate out of stroke when hydraulic pressure in the control circuit rises above the spring force.

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Introduction

The pump control, by varying the pressure at the servo piston, controls the displacement of fluid in the system circuit. Controls designed for Pressure Compensation (PC) or Load Sensing (LS) are available. For a detailed description of control operation, refer to Control options, operation.

Pump and control sectional view

LS control
(attached to endcap)
LS adjustment screw		LS spool
PC adjustment screw	PC spool
		Swashplate		Bias spring
Servo piston				Tapered roller bearing
Valve plate
Endcap				Input shaft
(axial ported)
Block spring				Shaft seal
			Slipper
Cylinder block	Piston
		Slipper retainer
				P101 659E

The system circuit

The pump receives fluid directly from the reservoir through the inlet line. A screen placed in the inlet protects the pump from large contaminants. The output of the pump is directed to a PVG-32 multisection load sensing directional control valve which directs fluid to the actuators in the system. Fluid returning from the system is cooled by a heat exchanger and cleaned by a filter before returning to the reservoir.

The speed of the actuators in the system depends on the volume of fluid being provided by the pump. The operating pressure varies depending on actuator load, but is limited to an adjustable maximum setting by the PC section of the pump control and by a system relief valve integrated into the side module of the PVG valve.

The position of the PVG valve sets the demand for flow in the system and communicates this to the pump control by means of a hydraulic signal (load sense signal). The pump will provide as much flow to the system as it demands while limiting the maximum pressure. Therefore flow and pressure in the system are compensated to meet requirements.

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Introduction

Pictorial circuit diagram

Double-ac ting cylinder

K/LFrame Series 45 open circuit axial piston pump with load sensing contro l

PVG 32 mulit-sec tion

load sensing contro l valve

Bi-directional gear moto r

Heat exchanger

Reservoir	Filter

P101 658E

System pressur e

Servo pressur e

Actuator pressur e

Load sense pressur e

Actuator retur n

Suction / case drain / system retur n

Full available flow is a function of pump displacement, operating speed, and efficiency. Refer to Series 45 Axial Piston Open Circuit Pumps Technical Information, BLN-10128 for details.

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Technical specifications

General specifications

Type of mounting

SAE-B mounting flange.

Auxiliary mounting pad options

SAE-A, SAE-B, or SAE-B-B

Control options

PC: Pressure Compensator

LS: Load Sensing (with PC)

Port options

Inlet and system ports:

•SAE flanged ports, code 61 or O-ring boss ports.

•Axial (end) ports or radial (side) ports.

All other ports:

•SAE straight thread O-ring boss.

Direction of rotation

Clockwise or counterclockwise.

Installation position

Installation position is discretionary. To satisfy inlet pressure conditions, it is recommended that the pump always be located below the lowest level of hydraulic fluid in the reservoir. The housing must always be filled with hydraulic fluid.

Technical specifications

Ratings

Specification		Unit	Frame L				Frame K
Displacement		cm3 [ in3]	25	[1.53]	30	[183]	38	[2.32]	45	[2.75]
Input speed	minimum	min-1 (rpm)	500		500		500		500
	continuous		3200		3200		2650		2650
	maximum		3600		3600		2800		2800
Working pressure - maximum (peak)		bar [psi]	350 [5075]		300 [4350]		350 [5075]		300 [4350]
Continuous working pressure
Flow at rated speed		l/min [gal/min]	76.2 [20.3]		90.0 [24.0]		108.3 [20.9]		126.0 [33.6]
Theoretical input torque at maximum displacement		N•m/bar [lbf•in/	0.395 [243]		0.477 [291]		0.605 [369]		0.716 [437]
		1000 psi]
Mass moment of inertia of internal rotating components		kg•m2[lbm•ft2]	0.0016 [0.037]		0.0015 [0.035]		0.0017 [0.040]		0.0020 [0.047]
Weight	Axial ports	kg [lbm]	19	[42]	19	[42]	19	[42]	19	[42]
	Radial ports		24	[53]	24	[53]	24	[53]	24	[53]

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Service Manual

Series 45 Frame K and L Open Circuit Axial Piston Pumps

Technical specifications

Hydraulic parameters

Inlet pressure

Minimum pressure, continuous = 0.8 bar absolute [23.2 in Hg] (at reduced maximum pump speed)

Minimum pressure, cold start = 0.5 bar absolute [14.8 in Hg]

Pressure compensator valve setting

Minimum: 100 bar [1450 psi]

Maximum: 260 bar [3770 psi]

Case pressure

Maximum continuous: 0.5 bar [7 psi] Above inlet

Intermittent: 2 bar [29 psi] Cold start

Hydraulic fluid

Refer to Danfoss publication Fluids and Filtration BLN-9887 or BC152886484524. For information on biodegradable fluids refer to Biodegradable Hydraulic Fluids 520L0465. See Fluid and filter maintenance for recommended fluid and filter change intervals.

Temperature range (1)

Intermittent (cold start): - 40° C [- 40° F]

Continuous: 82° C [180° F]

Maximum: (2) 104° C [220° F]

(1)Hydraulic fluid viscosity must be maintained within the prescribed limits.

(2)As measured at the hottest point in the system, e.g. drain line.

Fluid viscosity

Viscosity limits

Rating		mm2/s (cSt) [SUS]
ν continuous	minimum	9 [58]
	maximum	110 [500]
ν intermittent	minimum	6.4 [47]
	maximum (cold start)	1000 [4700]

Filtration

Required cleanliness level: ISO 4406 Class 18/13 or better. Refer to Danfoss publications Fluids and Filtration BLN-9887 or BC152886484524 and Design Guidelines for Selecting and Maintaining the Required Hydraulic Fluid Cleanliness 520L0465. See Fluid and filter maintenance for recommended fluid and filter change intervals.

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