Danfoss LPV User guide

Technical Information
Axial Piston Pumps
LPV
www.danfoss.com
Technical Information
LPV Axial Piston Pumps
Revision history Table of revisions
Date Changed Rev
April 2021 Changed document number from 'BC00000044' and '520L0954' to 'BC152886483590' and
removed obsolete end cap options
May 2018 add straight keyed shaft 0103
September 2017 update model code 0102
July 2015 Danfoss Layout 0100
January 2009 neutral assist return mechanism - changes AF
October 2008 added serial number plate drawing AE
April 2008 changes to auxilliary mounting dimensions AD
August 2007 revised endcap and loop flusing options in model code AC
May 2007 correct displacement errors AB
July 2006 First edition A-0
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Technical Information
LPV Axial Piston Pumps

Contents

General description
Operating parameters
System design parameters
Operation
Technical specifications
Product coding
Features and options
Installation drawings
Overview..............................................................................................................................................................................................4
Design...................................................................................................................................................................................................4
Typical applications.........................................................................................................................................................................4
LPV product specifications............................................................................................................................................................4
Design...................................................................................................................................................................................................6
Direct displacement drive system..............................................................................................................................................7
LPV Pump schematic diagram.....................................................................................................................................................7
Overview..............................................................................................................................................................................................8
Input speed.........................................................................................................................................................................................8
System pressure................................................................................................................................................................................8
Pressure Ratings................................................................................................................................................................................8
Viscosity............................................................................................................................................................................................... 8
Temperature.......................................................................................................................................................................................9
Case pressure.....................................................................................................................................................................................9
Independent braking system.......................................................................................................................................................9
Reservoir.............................................................................................................................................................................................. 9
Case drain......................................................................................................................................................................................... 10
Charge flow requirements..........................................................................................................................................................10
Loop flushing...................................................................................................................................................................................10
Bearing loads and life................................................................................................................................................................... 10
Applications with external shaft loads..............................................................................................................................10
Hydraulic unit life...........................................................................................................................................................................12
Mounting flange loads.................................................................................................................................................................12
Estimating overhung load moments.................................................................................................................................12
Input shaft torque rating and spline lubrication................................................................................................................ 13
Understanding and minimizing system noise.....................................................................................................................13
Sizing equations.............................................................................................................................................................................14
Fluids.................................................................................................................................................................................................. 14
Filtration system.............................................................................................................................................................................15
Charge filtration........................................................................................................................................................................ 15
Suction filtration....................................................................................................................................................................... 16
HPRV (High pressure relief valve).............................................................................................................................................17
Bypass function...............................................................................................................................................................................17
CPRV (Charge pressure relief valve)........................................................................................................................................ 17
Loop flushing valve.......................................................................................................................................................................18
Neutral return mechanism..........................................................................................................................................................18
Specifications...................................................................................................................................................................................20
LPV Model Code............................................................................................................................................................................. 23
Controls............................................................................................................................................................................................. 26
Direct displacement control.................................................................................................................................................26
Features and benefits..............................................................................................................................................................26
Control handle requirements...............................................................................................................................................26
Input shafts.......................................................................................................................................................................................26
Auxiliary mounting pads.............................................................................................................................................................27
SAE-A Auxiliary mounting..................................................................................................................................................... 27
LPV Installation drawings............................................................................................................................................................29
LPV Schematic.................................................................................................................................................................................30
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Technical Information
LPV Axial Piston Pumps

General description

Overview

Design

LPV is a family of variable displacement, axial piston pumps for closed circuit applications. The LPV family is uniquely designed to optimize performance, size, and cost, matching the work requirements of the demanding turf care and utility vehicle marketplace. This document gives the detailed specifications and features for LPV pumps.
High performance
Displacements 25 cm³/rev [1.53 in3/rev], 30 cm³/rev [1.83 in3/rev], 35 cm³/rev [2.14 in3/rev]
Speeds up to 3600 rpm
Pressures up to 210 bar [3045 psi] continuous, and 345 bar [5000 psi] peak
Direct displacement control
Latest technology
Customer-driven using quality function deployment (QFD) and design for manufacturability (DFM)
techniques Optimized valve plates for quiet operation
Compact package size minimizing installation space requirements
Single piece rigid housing to reduce noise and leak paths
Integrated neutral return mechanism for simplified installation
Optional loop flushing for circuit flexibility

Typical applications

LPV product specifications

Reliability
Designed to rigorous standards
Proven in both laboratory and field
Manufactured to rigid quality standards
Long service life
Turf care
Utility vehicles
Basic units
The LPV pumps provide an infinitely variable speed range between zero and maximum in both forward and reverse modes of operation.
LPV pumps are compact, high power density units. All models use the parallel axial piston/slipper concept in conjunction with a tiltable swashplate to vary the pump's displacement. Reversing the angle of the swashplate reverses the flow of fluid from the pump, reversing the direction of rotation of the output motor.
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Made in USA
Place of Manufac tur
e
Part Number
Serial
Number
Model Code
LPVAAADAEACCABDDD
P107852
83002847
A084012345
RAFFBNNN***
Technical Information
LPV Axial Piston Pumps
General description
LPV pump
Serial number plate
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Danfoss | April 2021 BC152886483590en-000301 | 5
P106271
Input shaft
Ball bearing
Needle bearing
Tapered roller bearing
Cylinder block
Valve plate
Cylinder block spring
Piston
Slipper
Swashplate
Trunion
Technical Information
LPV Axial Piston Pumps
General description

Design

LPV is a family of hydrostatic pumps for low to medium power applications with maximum loads of 345 bar [5000 psi]. You can apply these pumps with other products in a system to transfer and control hydraulic power.
LPV pumps provide an infinitely variable speed range between zero and maximum in both forward and reverse modes of operation. LPV pumps come in three displacements (25 cm3 [1.53 in3], 30 cm3 [1.83 in3], and 35 cm3 [2.14 in3]).
LPV pumps are compact, high power density units. All models use the parallel axial piston / slipper concept in conjunction with a tiltable swashplate to vary the pump's displacement. Reversing the angle of the swashplate reverses the flow of fluid from the pump, reversing the direction of rotation of the motor output.
LPV pumps have an internal neutral return mechanism for ease of installation, and are available with optional loop flushing for circuit flexibility. LPV pumps can receive charge flow from an auxiliary circuit or from a gear pump mounted on the auxiliary mounting pad. LPV pumps feature an SAE A auxiliary mounting pad to accept auxiliary hydraulic pumps for use in complementary hydraulic systems.
LPV pumps include a trunnion style direct displacement control.
LPV cross section
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Variable displacement pump
Input shaft
Cylinder
block
assembl y
HPRV valves
Loop flushing valves
OMR orbital motor
Suction flow
Servo pressur e
High pressur e
Case flow
Charge pressur e
Output shaft
Filter
Charge
pump
Reservoir
Heat exchanger
Heat exchanger bypass
Charge relief valve
Bypass
valve
P100586
Charge pressure inlet
Port A
Port B
P106287
L2
L1
Technical Information
LPV Axial Piston Pumps
General description

Direct displacement drive system

The direct displacement control varies the swashplate angle. Swashplate angle determines pump flow and motor speed.
Pictorial circuit diagram
The diagram shows an LPV pump driving an OMR motor. The system shown uses an external charge pump and external filter. Charge pressure relief valves, high pressure relief valves, and loop flushing valves are shown separated from the pump to provide clarity to the hydraulic system.

LPV Pump schematic diagram

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W
Technical Information
LPV Axial Piston Pumps

Operating parameters

Overview

Input speed

This section defines the operating parameters and limitations for LPV pumps with regard to input speeds and pressures. For actual parameters, refer to Technical specifications on page 20.
The table in Technical specifications on page 20, gives rated and maximum speeds for each displacement. Not all displacements operate under the same speed limits. Definitions of these speed limits appear below.
Continuous speed is the maximum recommended operating speed at full power condition. Operating at or below this speed should yield satisfactory product life. Do not exceed maximum pump speed during unloaded, on-road travel over level ground.
Maximum speed is the highest operating speed permitted. Exceeding maximum speed reduces pump life and can cause loss of hydrostatic power and braking capacity. Never exceed the maximum speed limit under any operating conditions.
Warning
Unintended vehicle or machine movement hazard.
The loss of hydrostatic drive line power, in any mode of operation (forward, neutral, or reverse) may cause the system to lose hydrostatic braking capacity. You must provide a braking system, redundant to the hydrostatic transmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic drive power loss.

System pressure

Pressure Ratings

The table in Technical specifications on page 20, gives maximum and maximum working pressure ratings for each displacement. Not all displacements operate under the same pressure limits. Definitions of the operating pressure limits appear below.
System pressure is the differential pressure between high pressure system ports. It is the dominant operating variable affecting hydraulic unit life. High system pressure, which results from high load, reduces expected life. Hydraulic unit life depends on the speed and normal operating, or weighted average, pressure that can only be determined from a duty cycle analysis.
Application pressure is the high pressure relief or pressure limiter setting normally defined within the order code of the pump. This is the applied system pressure at which the driveline generates the maximum calculated pull or torque in the application.
Maximum Working pressure is the highest recommended application pressure. Maximum working pressure is not intended to be a continuous pressure. Propel systems with application pressures at, or below, this pressure should yield satisfactory unit life given proper component sizing.
Maximum pressure is the highest allowable application pressure under any circumstance. Application pressures above maximum working pressure will only be considered with duty cycle analysis and factory approval.
Minimum low loop pressure must be maintained under all operating conditions to avoid cavitation.
All pressure limits are differential pressures referenced to low loop (charge) pressure. Subtract low loop pressure from gauge readings to compute the differential.

Viscosity

Maintain fluid viscosity within the recommended range for maximum efficiency and bearing life. Minimum viscosity should only occur during brief occasions of maximum ambient temperature and
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C
W
Technical Information
LPV Axial Piston Pumps
Operating parameters

Temperature

Case pressure

severe duty cycle operation. Maximum viscosity should only occur at cold start. Limit speeds until the system warms up. Refer to Specifications on page 20, for specifications.
Maintain fluid temperature within the limits shown in the table. Technical specifications on page 20. Minimum temperature relates to the physical properties of the component materials. Cold oil will not affect the durability of the pump components, however, it may affect the ability of the pump to provide flow and transmit power. Maximum temperature is based on material properties. Don't exceed it. Measure maximum temperature at the hottest point in the system. This is usually the case drain. Refer to
Specifications on page 20, for specifications.
Ensure fluid temperature and viscosity limits are concurrently satisfied.
Do not allow case pressure to exceed ratings under normal operating conditions. During cold start, keep case pressure below maximum intermittent case pressure. Size drain plumbing accordingly.
Caution

Independent braking system

Reservoir

Possible component damage or leakage.
Operation with case pressure in excess of stated limits may damage seals, gaskets, and/or housings, causing external leakage. Performance may also be affected since charge and system pressure are additive to case pressure.
Warning
Unintended vehicle or machine movement hazard.
The loss of hydrostatic drive line power, in any mode of operation (forward, neutral, or reverse) may cause the system to lose hydrostatic braking capacity. You must provide a braking system, redundant to the hydrostatic transmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic drive power loss.
The reservoir provides clean fluid, dissipates heat, and removes trapped air from the hydraulic fluid. It allows for fluid volume changes associated with fluid expansion and cylinder differential volumes. Minimum reservoir capacity depends on the volume needed to perform these functions. Typically, a capacity of 5/8 of the charge pump flow (per minute) is satisfactory for a closed reservoir. Open circuit systems sharing a common reservoir require greater fluid capacity.
Locate the reservoir outlet (suction line) near the bottom, allowing clearance for settling foreign particles. Use a 100 - 125 µm screen covering the outlet port.
Place the reservoir inlet (return lines) below the lowest expected fluid level, as far away from the outlet as possible. Use a baffle (or baffles) between the reservoir inlet and outlet ports to promote de-aeration and reduce fluid surging.
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Technical Information
LPV Axial Piston Pumps

System design parameters

Case drain

Charge flow requirements

Connect the case drain line to one of the case outlets to return internal leakage to the system reservoir. Use the higher of the outlets to promote complete filling of the case. Case drain fluid is typically the hottest fluid in the system. Return case drain flow through the heat exchanger to the reservoir.
All LPV pumps applied in closed circuit installations require charge flow. The charge pump provides flow to make up internal leakage, maintain a positive pressure in the main circuit, provide flow for cooling and filtration, replace any leakage losses from external valving or auxiliary systems, and to provide flow and pressure for the control system.
Many factors influence the charge flow requirements and charge pump size selection. These factors include system pressure, pump speed, pump swashplate angle, type of fluid, temperature, size of heat exchanger, length and size of hydraulic lines, control response characteristics, auxiliary flow requirements, hydrostatic motor type, etc. When sizing and selecting hydrostatic units for an application, it is frequently not possible to have all the information necessary to accurately evaluate all aspects of charge pump size selection.
Maintain charge pressure at the level specified in the table Technical specifications on page 20 under all operating conditions to prevent damage to the transmission. Danfoss recommends testing under actual operating conditions to verify this.
Charge pump displacement should be at least 10% of the total displacement of all axial piston components in the system. However, unusual application conditions may require a more detailed review of charge pump sizing. Refer to Selection of Drive line Components, BLN-9985, for a more detailed selection procedure, or contact your Danfoss representative for assistance.

Loop flushing

Bearing loads and life

Closed circuit systems may require loop flushing to meet temperature and cleanliness requirements. A loop flushing valve removes hot fluid from the low pressure side of the system loop for additional cooling and filtering. Ensure the charge pump provides adequate flow for loop flushing and the loop flushing valve does not cause charge pressure to drop below recommended limits.
LPV utilizes a special loop flushing spool design. On dual path systems, take special care to verify acceptable performance.
Bearing life is a function of speed, system pressure, charge pressure, and swashplate angle, plus any external side or thrust loads. The influence of swashplate angle includes displacement as well as direction. External loads are found in applications where the pump is driven with a side/thrust load (belt or gear) as well as in installations with misalignment and improper concentricity between the pump and drive coupling. All external side loads will act to reduce the normal bearing life of a pump. Other life factors include oil type and viscosity.
In vehicle propel drives with no external shaft loads and where the system pressure and swashplate angle are changing direction and magnitude regularly, the normal L20 bearing life (80 % survival) will exceed the hydraulic load-life of the unit.
In non propel drives such as vibratory drives, conveyor drives, or fan drives, the operating speed and pressure are often nearly constant and the swashplate angle is predominantly at maximum. These drives have a distinctive duty cycle compared to a propulsion drive. In these types of applications a bearing life review is recommended.

Applications with external shaft loads

LPV pumps have bearings that can accept some external radial and thrust loads. When external loads are present, the allowable radial shaft loads are a function of the load position relative to the mounting
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0° Re
180° Re
90° Re
270° Re
Axis of swashplate rotation
End view
of shaft
P100595
Orient radial shaft load to 90° or 270° (opposite of block load)
Technical Information
LPV Axial Piston Pumps
System design parameters
flange, the load orientation relative to the internal loads, and the operating pressures of the hydraulic unit. In applications with external shaft loads, you can minimize the impact on bearing life with proper orientation of the load.
Optimum pump orientation is a consideration of the net loading on the shaft from the external load, the pump rotating group and the charge pump load.
In applications where the pump is operated such that nearly equal amounts of forward vs reverse
swashplate operation is experienced; bearing life can be optimized by orientating the external side load at 0° or 180° such that the external side load acts 90° to the rotating group load.
In applications where the pump is operated such that the swashplate is predominantly (> 75 %) on
one side of neutral (ie vibratory, conveyor, typical propel); bearing life can be optimized by orientating the external side load generally opposite (90° or 270°) the internal rotating group load. The direction of internal loading is a function of rotation and which system port has flow out. Contact Danfoss for a bearing life review if external side loads are present.
You can calculate the maximum allowable radial load (Re), using the formula below, the maximum external moment (Me) from the table on the next page, and the distance (L) from the mounting flange to the load.
Re = Me / L
Avoid thrust loads in either direction. If continuously applied external radial loads are 25% of the maximum allowable or more, or thrust loads
are known to occur, contact your Danfoss representative for an evaluation of unit bearing life. Tapered output shafts or clamp-type couplings are recommended for applications where radial shaft side
loads are present.
Direction of external shaft load
Shaft loading parameters
R
e
M
e
L Distance from mounting flange to point of load F
b
T
e
Maximum radial load Maximum external moment
Force of block Thrust load
Maximum external shaft moments
LPV
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Me /N•m [in•lbf] 101 [890]
R
T
P106280
L
e
F
e
b
0
180
90
270
Re Re
Re
Re
Technical Information
LPV Axial Piston Pumps
System design parameters

Hydraulic unit life

Diagram of external radial shaft loads
Hydraulic unit life is the life expectancy of the hydraulic components. It is a function of speed and system pressure. System pressure is the dominant operating variable. High pressure, which results from high load, reduces expected life.
Design the hydraulic system to a projected machine duty cycle. Know the expected percentages of time at various loads and speeds. Ask your Danfoss representative to calculate an appropriate pressure based your hydraulic system design. If duty cycle data is not available, input power and pump displacement are used to calculate system pressure.
All pressure limits are differential pressures (referenced to charge pressure) and assume normal charge pressure.
LPV pumps will meet satisfactory life expectancy if applied within the parameters specified in this bulletin. For more detailed information on hydraulic unit life see Pressure and Speed Limits,
BC152886484313.

Mounting flange loads

Estimating overhung load moments

Adding auxiliary pumps and/or subjecting pumps to high shock loads may result in excessive loading of the mounting flange. Applications which experience extreme resonant vibrations or shock may require additional pump support. You can estimate the overhung load moment for multiple pump mounting using the formula below.
MS = GS (W1L1 + W2L2 + ... +WnLn) MC = GC (W1L1 + W2L2 + ... +WnLn) Where: MC = Rated load moment N•m [lbf•in] MS = Shock load moment N•m [lbf•in] GC = Rated (vibratory) acceleration (G’s)* m/s2 [ft/s2] GS = Maximum (shock) acceleration (G’s)* m/s2 [ft/s2] Wn = Weight of nth pump Ln = Distance from mounting flange to CG (center of gravity) of nth pump (Refer to Installation drawings on page 29 to locate CG of pump.)
* Carry out calculations by multiplying gravity (g = 9.81 m/s2 [32 ft/s2]) with a given factor. This factor depends on the application.
Refer to Specifications on page 20, for allowable overhung load moment values.
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P106285
Center of gravity - pump 1
Center of gravity - pump 2
L 1
L 2
Mounting flange
Technical Information
LPV Axial Piston Pumps
System design parameters
Shaft loading parameters

Input shaft torque rating and spline lubrication

A spline running in oil-flooded environment provides superior oxygen restriction in addition to contaminant flushing. An oil-flooded spline is found in a pump to pump drive (mounted on the auxiliary pad of another pump). An oil-flooded spline connection can withstand a continuously applied torque up to the published maximum rating. Maximum torque ratings are based on torsional fatigue strength of the shaft and assume a maximum of 200,000 load reversals.
Coupling arrangements that are not oil-flooded require a reduced torque rating due to spline tooth wear. Contact your Danfoss representative for torque ratings if your application involves non oil-flooded couplings.
Danfoss recommends mating splines adhere to ANSI B92.1-Class 5. Danfoss external splines are modified class 5 fillet root side fit. The external major diameter and circular tooth thickness dimensions are reduced to ensure a good clearance fit with the mating spline. See Input shafts on page 26 for full spline dimensions and data.
Maintain a spline engagement at least equal to the pitch diameter to maximize spline life. Spline engagement of less than ¾ pitch diameter is subject to high contact stress and spline fretting.
Alignment between the mating spline's pitch diameters is another critical factor in determining the operating life of a splined drive connection. Plug-in, or rigid spline drive installations can impose severe radial loads on the shaft. The radial load is a function of the transmitted torque and shaft eccentricity. Increased spline clearance will not totally alleviate this condition; but, increased spline clearance will prevent mechanical interference due to misalignment or radial eccentricity between the pitch diameters of the mating splines. Maximize spline life by adding an intermediate coupling between the bearing supported splined shafts.
Torques are additive for multiple pump installations. Ensure total through torque for the main pump and auxiliary pump does not exceed published maximum shaft torque. See Input shafts on page 26 for shaft torque ratings.

Understanding and minimizing system noise

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A table in the Specifications on page 20, gives sound levels for each displacement. Sound level data are collected at various operating speeds and pressures in a semi-anechoic chamber. Many factors contribute to the overall noise level of any application. Here is some information to help understand the nature of noise in fluid power systems, and some suggestions to help minimize it.
Noise is transmitted in fluid power systems in two ways: as fluid borne noise, and structure borne noise. Fluid-borne noise (pressure ripple or pulsation) is created as pumping elements discharge oil into the
pump outlet. It is affected by the compressibility of the oil, and the pump's ability to transition pumping
Technical Information
LPV Axial Piston Pumps
System design parameters

Sizing equations

elements from high to low pressure. Pulsations travel through the hydraulic lines at the speed of sound (about 1400 m/s [4600 ft/sec] in oil) until there is a change (such as an elbow) in the line. Amplitude varies with overall line length and position.
Structure-borne noise is transmitted wherever the pump casing connects to the rest of the system. The way system components respond to excitation depends on their size, form, material, and mounting.
System lines and pump mounting can amplify pump noise. Follow these suggestions to help minimize noise in your application:
Use flexible hoses.
Limit system line length.
If possible, optimize system line position to minimize noise.
If you must use steel plumbing, clamp the lines.
If you add additional support, use rubber mounts.
Test for resonants in the operating range, if possible avoid them.
Use these equations to help choose the right pump size and displacement for your application. An evaluation of the machine system to determine the required motor speed and torque to perform the necessary work function initiates the design process. Refer to Selection of drive line components, BLN-9985, for a more complete description of hydrostatic drive line sizing. First select motor size to transmit the maximum required torque. Then select pump as a flow source to achieve the maximum motor speed.

Fluids

Ratings and performance data are based on operating with hydraulic fluids containing oxidation, rust and foam inhibitors. These fluids must possess good thermal and hydrolytic stability to prevent wear, erosion, and corrosion of pump components. Never mix hydraulic fluids of different types.
Fire resistant fluids are also suitable at modified operating conditions. Please see Hydraulic Fluids and Lubricants Technical Information, BC152886484524, for more information. Refer to Experience with
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Technical Information
LPV Axial Piston Pumps
System design parameters

Filtration system

Biodegradable Hydraulic Fluids Technical Information, 520L0465, for information relating to biodegradable fluids.
The following hydraulic fluids are suitable:
Hydraulic Oil ISO 11 158 - HM (Seal compatibility and vane pump wear resistance per DIN 51 524-2
must be met) Hydraulic Oil ISO 11 158 - HV (Seal compatibility and vane pump wear resistance per DIN 51 524-3
must be met) Hydraulic Oil DIN 51 524-2 - HLP• Hydraulic Oil DIN 51 524-3 - HVLP
Automatic Transmission Fluid (ATF) A Suffix A (GM)
Automatic transmission fluid Dexron II (GM), which meets Allison C-3 and Caterpillar TO-2 test
Automatic transmission fluid M2C33F and G (Ford)
Engine oils API classification SL, SJ (for gasoline engines) and CI-4, CH-4, CG-4, CF-4 and CF (for diesel
engines) Super Tractor Oil Universal (STOU) special agricultural tractor fluid
To prevent premature wear, ensure only clean fluid enters the hydrostatic transmission circuit. Danfoss reccommends a filter capable of controlling the fluid cleanliness to ISO 4406 class 22/18/13 (SAE J1165) or better, under normal operating conditions.
Filtration strategies include suction or pressure filtration. The selection of a filter depends on a number of factors including the contaminant ingression rate, the generation of contaminants in the system, the required fluid cleanliness, and the desired maintenance interval. Select filters to meet the above requirements using rating parameters of efficiency and capacity.
You can express measured filter efficiency with a Beta ratio1 (βX). For simple suction-filtered closed circuit transmissions and open circuit transmissions with return line filtration, a filter with a β-ratio within the range of β circuits with cylinders being supplied from the same reservoir, we recommend a considerably higher filter efficiency. This also applies to systems with gears or clutches using a common reservoir. These systems typically require a charge pressure or return filtration system with a filter β-ratio in the range of β
= 75 (β10 ≥ 10) or better.
15-20
Because each system is unique, only a thorough testing and evaluation program can fully validate the filtration system. Please see Design Guidelines for Hydraulic Fluid Cleanliness Technical Information, BC152886482150 for more information.
Ensure fluid entering pump is free of contaminants to prevent damage (including premature wear) to the system. LPV pumps require system filtration capable of maintaining fluid cleanliness at ISO 4406-1999 class 22/18/13 or better.
Consider these factors when selecting a system filter:
Cleanliness specifications
Contaminant ingression rates
Flow capacity
Desired maintenance interval
= 75 (β10 ≥ 2) or better should be satisfactory. For some open circuit systems, and closed
35-45
Locate filter either on the inlet (suction filtration) or discharge (charge pressure filtration) side of the charge pump. Either strategy is applicable for LPV pumps.

Charge filtration

The pressure filter is remotely mounted in the circuit after the charge pump, as shown in the accompanying illustration.
1
Filter βx-ratio is a measure of filter efficiency defined by ISO 4572. It is defined as the ratio of the number of particles greater than a given diameter (“x” in microns) upstream of the filter to the number of these particles downstream of the filter.
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Danfoss | April 2021 BC152886483590en-000301 | 15
Reservoir
Filter
with bypass
Charge
pump
Charge relief
valve
To pump case
To Low Pressure
side of loop
and ser vo contro l
Strainer
P106279
Reservoir
Filter
Charge
pump
Charge relief
valve
To pump case
To low pressure
side of loop
and ser vo contro l
Strainer
P106352
Technical Information
LPV Axial Piston Pumps
System design parameters
Filters used in charge pressure filtration circuits must be rated to at least 34.5 bar [500 psi] pressure. Danfoss recommends locating a 100 - 125 µm screen in the reservoir or in the charge inlet line when using charge pressure filtration.
A filter bypass valve is necessary to prevent damage to the system. In the event of high pressure drop associated with a blocked filter or cold start-up conditions, fluid will bypass the filter. Avoid working with an open bypass for an extended period. We recommend a visual or electrical bypass indicator. Proper filter maintenance is mandatory.
Charge filtration

Suction filtration

The suction filter is placed in the circuit between the reservoir and the inlet to the charge pump as shown in the accompanying illustration.
Suction filtration
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P106273
P106286
C
Technical Information
LPV Axial Piston Pumps

Operation

HPRV (High pressure relief valve)

LPV pumps are equipped with a combination high pressure relief and charge check valve. The high­pressure relief function is a dissipative (with heat generation) pressure control valve for the purpose of limiting excessive system pressures. The charge check function acts to replenish the low-pressure side of the working loop with charge oil. Each side of the transmission loop has a dedicated HPRV valve that is non-adjustable with a factory set pressure. When system pressure exceeds the factory setting of the valve, oil is passed from the high pressure system loop, into the charge gallery, and into the low pressure system loop via the charge check. The high pressure relief valve used on LPV is designed to remove pressure spikes for short periods of time. Operating over the high pressure relief valve for extended periods may damage the pump.
HPRV valve

Bypass function

The LPV contains a dedicated bypass valve. the bypass function is activated when the bypass valve is mechanically backed out 3 full turns (maximum). The bypass function allows a machine or load to be moved without rotating the pump shaft or prime mover.
Bypass valve
Excessive speed or extended movement will damage the pump and motor(s)
Avoid excessive speeds and extended load/vehicle movement. Do not move the load or vehicle more than 20 % of maximum speed or for longer than 3 minutes. When the bypass function is no longer needed, reseat the bypass valve to the normal operating position.

CPRV (Charge pressure relief valve)

An internal charge relief valve regulates charge pressure. The charge pump supplies pressure to maintain a minimum pressure in the low side of the transmission loop.
Caution
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P106274
P106276
W
Technical Information
LPV Axial Piston Pumps
Operation
CPRV valve
Minimum charge pressure is the lowest pressure allowed to maintain a safe working condition in the low side of the loop.
Maximum charge pressure is the highest charge pressure allowed which provides normal component life. Elevated charge pressure can be used as a secondary means to reduce the swashplate response time. The charge pressure setting listed in the order code is the set pressure of the charge relief valve with the pump in neutral, operating with 5 gpm of charge flow. The charge pressure setting is referenced to case pressure. Charge pressure is the differential pressure above case pressure.
LPV is designed for a maximum charge flow of 57 L/min [15 US gal/min].

Loop flushing valve

Neutral return mechanism

LPV pumps incorporate an optional integral loop flushing valve, which removes heat and contaminants from the main loop.
LPV utilizes a special loop flushing spool design. On dual path systems, take special care to verify acceptable performance.
Loop flushing valve
The neutral return mechanism mechanically returns the pump to zero displacement. A cam allows precise zero displacement adjustment.
Maximum return force of the neutral return mechanism is 5.65 N•m [50 lbf•in]
Warning
Failure of the pump to return to neutral in the absence of control input will cause unintended vehicle movement. Some control systems may require an additional neutral return mechanism to
overcome friction in the control linkage. Verify pump returns to neutral under all operating conditions when the control is released.
18 | © Danfoss | April 2021 BC152886483590en-000301
P106277
Adjusting screw
Lock/seal nut
Shaft
Swashplate
Neutral return arm
Adjusting cam
P106278
Technical Information
LPV Axial Piston Pumps
Operation
Neutral return adjustment screw
Neutral return mechanism
©
Danfoss | April 2021 BC152886483590en-000301 | 19
Technical Information
LPV Axial Piston Pumps

Technical specifications

Specifications

General specifications
Design Axial piston pump of trunion swashplate design with variable displacement Direction of rotation Clockwise, counter-clockwise Port connections Main pressure ports: SAE straight thread O-ring boss Recommended installation
position
Pump installation recommended with control position on the bottom or side. Consult Danfoss for non conformance to these guidelines. The housing must always be filled with hydraulic fluid.
Physical properties
Displacement
Feature Unit 25 30 35
Maximum displacement cm³ [in³] 25 [1.53] 30 [1.83] 35 [2.14] Flow at rated speed (theoretical) l/min
[US gal/min]
Input torque at maximum displacement (theoretical)
Mass moment of inertia of internal rotating components
Weight kg [lb] 23 [51] Rotation Clockwise, counter-clockwise Mounting SAE B 2 bolt Auxiliary mounting SAE J744 A 9T, SPCL 11T System ports (type) 1 1/16-12 UNF-2B ORB System ports (location) Twin radial Control types Direct displacement control Shafts Splined SAE 13 tooth, 15 tooth Case drain ports 1 1/16-12 SAE ORB
N•m/ bar [lbf•in/1000 psi]
kg•m² [slug•ft²]
85.2 [22.5]
0.4 [244]
0.001670 [0.0012]
104.9 [27.7]
0.5 [291]
0.001580 [0.00120]
137.0 [36.2]
0.6 [340]
0.001530 [0.0011]
Operating parameters
Displacement
Rating Units 25 30 35
Input speed
Pressure maximum working bar [psi] 400 [5800] 350 [5075] 300 [4350]
External shaft loads External moment (Me) N•m [lbf•in] 7.7 [68]
Bearing life (max. swashplate angle and max. continuous speed)
Charge pressure minimum bar [psi] 6 [87]
2
minimum min-1 (rpm) 500 500 500 continuous 3400 3500 3600 maximum 3950 4150 4300
maximum 415 [6020] 400 [5800] 350 [5075]
Thrust in (Tin), out (Tout) N [lbf] 750 [169] at 210 bar [3045 psi] B10 hours 120,000 63,000 37,000
maximum 30 [435]
20 | © Danfoss | April 2021 BC152886483590en-000301
Technical Information
LPV Axial Piston Pumps
Technical specifications
Operating parameters (continued)
Displacement
Rating Units 25 30 35
Case pressure rated bar [psi] 2 [29]
maximum 6 [87]
Sound levels
dB(A) 100 bar [1450 psi] 200 bar [2900 psi] 300 bar [4350 psi] Displ. cm³ [in³] 1000 min-1(rpm) 1000 min-1(rpm) 1000 min-1(rpm) 25 [1.53] 62 66 68 35 [2.14] 61 66 69 dB(A) 100 bar [1450 psi] 200 bar [2900 psi] 300 bar [4350 psi] Displ. cm³ [in³] 3000 min-1(rpm) 3000 min-1(rpm) 3000 min-1(rpm) 25 [1.53] 70 74 76 35 [2.14] 71 75 80
1
Sound data was collected per ISO 4412-1 in a semi-anechoic chamber. Values have been adjusted (-3 dB)
1
to reflect anechoic levels.
Fluid specifications
Feature Unit Displacement cm³ [in³]
25 [1.53], 30 [1.83], 35 [2.14]
Viscosity Minimum mm2/sec
Recommended range 12-60 [66-278] Maximum 1600 [7500]
Temperature
2
Range
Filtration Cleanliness per ISO 4406 22/18/13
Minimum °C [°F] -40 [-40] Rated 82 [180] Maximum intermittent 100 [212]
Efficiency (charge pressure filtration)
Efficiency (suction filtration) β Recommended inlet screen
mesh size
[SUS]
β-ratio β
μm 100 - 125
7 [47]
= 75 (β10≥ 10)
15-20
= 75 (β10≥ 2)
35-45
2
At the hottest point, normally case drain port.
Mounting flange - allowable overhung parameters
Continuous load moment (Mc) Shock load moment (Ms)
N•m [lbf•in] N•m [lbf•in] 361 [3200] 617 [5470]
©
Danfoss | April 2021 BC152886483590en-000301 | 21
Technical Information
LPV Axial Piston Pumps
Technical specifications
Mounting flange - G-factors for sample applications
Application Continuous (vibratory)
acceleration (Gc)
Skid steer loader 6 10 Trencher
(rubber tires) Asphalt paver 6 6 Windrower 6 5 Aerial lift 6 4 Turf care vehicle 6 4 Vibratory roller 6 10
6 8
Maximum (shock) acceleration (Gs)
Applications experiencing extreme resonant vibrations may require additional pump support. Refer to
System design parameters on page 10 for information concerning mounting flange loads.
22 | © Danfoss | April 2021 BC152886483590en-000301
Swashplate Group
Seal Group
Input Shaft
Rotation, Kit, & Valveplate
Charge Pump
Charge Pressure
Neutral Assist
Bypass Valve
Control Handle
Auxiliary Mounting Flange
C D E F G H K L P S
L P V
■ ■ ■ ■ ■ □ □
□□
□□□
□□□
Special Features
(Non Hardware)
System Pressure
Protection
Special Hardware
Control Orifice
Z
Product
□□
Control Orientation & Type
□□
□□□
N
J
Endcap, Loop Flush,
& Aux Pad
MRT
Technical Information
LPV Axial Piston Pumps

Product coding

LPV Model Code

Product
Code Description
LPV LPV variable displacement pump
C Swashplate Group
Code Description
A Right hand swashplate C Left hand swashplate
D Seal Group
Code Description
A Standard shaft seal
E Input Shaft Configuration
Code Description
A 13 Tooth splined 16/32 pitch B 15 Tooth splined 16/32 pitch C 20 Tooth splined 24/48 pitch D Round straight key Dia. 22.2mm (key not supplied)
F Rotating kit, rotation and valveplate
Code Displacement
A CW rotation 25 cm³/rev [1.50 in³/rev] B CW rotation 30 cm³/rev [1.83 in³/rev] C CW rotation 35 cm³/rev [2.14 in³/rev] D CCW rotation 25 cm³/rev [1.50 in³/rev] E CCW rotation 30 cm³/rev [1.83 in³/rev] F CCW rotation 035 cm³/rev [2.14 in³/rev] J CW rotation 25 cm³/rev [1.50 in³/rev] low leakage K CW rotation 30 cm³/rev [1.83 in³/rev] low leakage L CW rotation 35 cm³/rev [2.14 in³/rev] low leakage
G Charge Pump Displacement
Code Description
A None
©
Danfoss | April 2021 BC152886483590en-000301 | 23
Technical Information
LPV Axial Piston Pumps
Product coding
H Charge Pressure Relief Valve Setting
Code Description
C 9.0 bar [130 psi] E 11.0 bar [160 psi] G 14.0 bar [200 psi] I 18.0 bar [260 psi] K 23.0 bar [335 psi]
J End Cap and Loop Flushing
Code Description
AA High loop flushing, 7.6 l/min [2 US gal/min] at 260 psid charge, RH control, SAE A flange 0
Deg.
AB Low loop flushing, 3.8 l/min [1 US gal/min] at 260 psid charge, RH control, SAE A flange 0
Deg. AC No loop flushing, RH control, SAE A flange 0 Deg. DA High loop flushing, 7.6 l/min [2 US gal/min] at 260 psid charge, RH control, SAE A flange 90
Deg. DB Low loop flushing, 3.8 l/min [1 US gal/min] at 260 psid charge, RH control, SAE A flange 90
Deg. DC No loop flushing, RH control, SAE A flange 90 Deg. EC No loop flushing, RH control, SAE B flange 0 Deg. FA High loop flushing, 7.6 l/min [2 US gal/min] at 260 psid charge, single side only, SAE A
flange 90 Deg.
K Neutral Return
Code Description
C Neutral assist, standard D Neutral assist, high force
L Bypass Valve
Code Description
A Bypass valve
M System Pressure Protection
Code Description
AAA None/none BBB 175 bar [2540 psi]/175 bar [2540 psi] BCC 190 bar [2755 psi]/190 bar [2755 psi] BDD 210 bar [3045 psi]/210 bar [3045 psi] BEE 230 bar [3325 psi]/230 bar [3325 psi] BFF 250 bar [3625 psi]/250 bar [3625 psi] BGG 280 bar [4060 psi]/ 280 bar [4060 psi] BHH 300 bar [4350 psi]/300 bar [4350 psi] BJJ 345 bar [5000 psi]/345 bar [5000 psi] BMM 140 bar [2030 psi]/ 140 bar [2030 psi] BRR 325 bar [4712 psi]/ 325 bar [4712 psi]
24 | © Danfoss | April 2021 BC152886483590en-000301
Technical Information
LPV Axial Piston Pumps
Product coding
N Control Type and Orientation
Code Description
DR Direct displacement control, right side DL Direct displacement control, left side
P Control
Code Description
A DDC
R Control Orifice Diameter
Code Description
FF N/A
S Housing and Auxiliary Mounting
Code Description
A SAE A, 11T spline, running cover B SAE A, 9T spline, running cover E SAE B, 13T spline, running cover N SAE A, none, running cover
T Special Hardware Features
Code Description
NNN None
ZZ Special Features (non hardware)
Code Description
*** None
©
Danfoss | April 2021 BC152886483590en-000301 | 25
20.637 [0.8125] pitch diameter 30° pressure angle 13 teeth 16/32 pitch fillet root side fit
P106283
41.2 ± 0.8
[1.622 ± 0.03]
15.2 ± 0.09
[0.5984 ± 0.0035]
7.9 ± 0.8
[0.31 ± 0.03]
20.622 [0.8119] pitch diameter 30° pressure angle 15 teeth 16/32 pith fillet root side fit
P106284
41.2 ± 0.8
[1.62 ± 0.03]
18.5 ± 0.09
[0.7283 ± 0.0035]
7.9 ± 0.8
[0.31 ± 0.03]
Technical Information
LPV Axial Piston Pumps

Features and options

Controls

Direct displacement control

The LPV pump features Direct Displacement Control (DDC). The swashplate angle is set directly by a control lever or linkage attached directly to the swashplate trunion. Control lever movement changes the displacement and flow direction of the pump by increasing or decreasing the swashplate angle.
The control input shaft is on the right hand side of the pump. Contact your Danfoss representative for availability of left side control input.

Features and benefits

Simple, low cost design
Pump output is maintained regardless of load.
Pump will return to neutral if control input is removed (if equipped with optional neutral return
mechanism)

Control handle requirements

Maximum allowable trunnion torque is 79.1 N•m [700 lbf•in]. Minimum available centering moment is 5.7 N•m [50 lbf•in]. The actual value will vary due to the influence of pump operating conditions. Maximum swashplate angle is ±18°. For mating dimensions, see Installation drawings on page 29.

Input shafts

Shaft data
Code Description Maximum torque
N•m [lbf•in]
A 13 tooth spline
16/32 pitch (ANSI B92.1 1966 - Class 6e)
B 15 tooth spline
16/32 pitch (ANSI B92.1 1966 - Class 6e)
226 [2000]
362 [3200]
Drawing
26 | © Danfoss | April 2021 BC152886483590en-000301
P108847
6.9 Max. [0.27]
21.166 [0.8333] pitch diameter 30° pressure angle 20 teeth 24/48 pitch fillet root side fit
48.6 Max. [1.91]
22.48 ± 0.5
[0.89 ± 0.02]
41.9 [1.65] Max.
18.58 ± 0.1
[0.731 ± 0.005]
6.9 [0.27] Max.
22.225
+0.03
0
[0.875 ]
+0.001
0
6.35 +0.05
0
[0.250 ]
+0.002
0
8.175 ± 0.325
[0.322 ± 0.013]
+0.05
0
19
[0.750 ]
+0.0180
0
9 tooth coupling
SAE-A 9T
16.47 [0.65]
P106322
11 tooth coupling
SAE-A SPCL 11T
31.8
[1.25]
19.77 [0.78]
13.5 [0.531] minimum tooth engagement
15 [0.590] minimum tooth engagement
31.8
[1.25]
88.62 [3.49]
82.6
[3.25]
1.96
[0.08]
O-ring seal required
82.22 [3.237] I.D. x
2.62 [0.103] dia. cross section
O-ring seal required
82.22 [3.237] I.D. x
2.62 [0.103] dia. cross section
82.6
[3.25]
88.62 [3.49]
1.96
[0.08]
*
* dimension is short of standard dimension
13 tooth coupling
ANSI B92.1B Class 7E
44.73 [1.761]
20.1 [0.792]
1.96 [0.77]
Ø107.82 [4.245]
Ø101.65 [4.002]
Technical Information
LPV Axial Piston Pumps
Features and options
Shaft data (continued)
Code Description Maximum torque
N•m [lbf•in]
C
20 tooth spline 24/48 pitch (ANSI B92.1 1966 - Class 6e)
241 [2133]
Drawing
See Input shaft torque rating and spline lubrication on page 13 for an explanation of maximum torque.

Auxiliary mounting pads

Dimensions
©
D
Straight key
226 [2000]
22.2 mm [0874 in] (ANSI B92.1 1966 - Class 6e)

SAE-A Auxiliary mounting

Danfoss | April 2021 BC152886483590en-000301 | 27
mm [in]
D
max
.
E
max.
Mounting
flange (ref.)
Undercut
spline
Sled-runner
spline
A Ø 82.55
[3.250]
R 0.8 [0.03] max.
B
max.
C
max.
Coupling
Recommended cutter clearance
2.3 [0.090]
P101079
Technical Information
LPV Axial Piston Pumps
Features and options
Dimensions in mm [in]
The auxiliary pad operates under case pressure. Use an O-ring to seal the auxiliary pump mounting flange to the pad.
The combination of auxiliary shaft torque and main pump torque must not exceed the maximum pump input shaft rating. The table in Input shafts on page 26, gives input shaft torque ratings for each frame size.
Mating pump specifications
Dimensions
Measurement SAE A (9T) or (11T)
units mm [in]
A 82.55
[3.250]
B 6.35
[0.250]
C 17.78
[0.700]
D* 31.75
[1.250]
E 17.78
[0.700]
* The 11 tooth auxiliary pad option requires a special short shaft on the mating pump due to reduced clearance to the LPV pump shaft.
28 | © Danfoss | April 2021 BC152886483590en-000301
182.9 [7.20]
1 1/16 -12 SAE straight thread O-ring boss case drain
2X 3/8 -16 UNC-2B THD
72.7
[2.86]
128.8 [5.07]
7/8 -14 SAE straight thread O-ring boss charge inlet
Charge pressure relief valve
39.2
[1.54]
2X 58.9
[2.32]
94.3
[3.71]
125
[4.92]
182.9 [7.20]
246.3 [9.70]
92.1
[3.63]
18°
Max.
Displ.
18°
Max.
Displ.
F1
R1
111.1 [4.37]
82.6
[3.25]
128.8 [5.07]
2X 35.1
[1.38]
1 1/16 -12 SAE straight thread O-ring boss system port A
1 1/16 -12 SAE straight thread O-ring boss system port B
1 1/16 -12 SAE straight thread O-ring boss case drain (alternate)
Loop flushing valve location
HPRV valve
P106281
Trunion
19.84 dia. [0.781]
45°
15.82 [0.623] (2) Places
CONTROL TRUNNION DETAIL
2X 3/8 -16 x 1 UNC THD (hole is 20 mm deep)
Technical Information
LPV Axial Piston Pumps

Installation drawings

LPV Installation drawings

©
Danfoss | April 2021 BC152886483590en-000301 | 29
2X 73 [2.87]
CW
P106281
CCW
HPRV valve
Bypass valve
Loop flushing valve
2X Ø14.3
+0.25
-0.12
[0.563
+0.010
-0.005
]
L1
L2
Charge pressure inlet
Port A
Port B
P106270
Technical Information
LPV Axial Piston Pumps
Installation drawings
Shaft rotation
CW CCW
Handle angle F1 R1 R1 F1 Port flow A out in in out
B in out out in

LPV Schematic

30 | © Danfoss | April 2021 BC152886483590en-000301
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2800 East 13th Street Ames, IA 50010, USA Phone: +1 515 239 6000
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Building #22, No. 1000 Jin Hai Rd Jin Qiao, Pudong New District Shanghai, China 201206 Phone: +86 21 2080 6201
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Danfoss Power Solutions is a global manufacturer and supplier of high-quality hydraulic and electric components. We specialize in providing state-of-the-art technology and solutions that excel in the harsh operating conditions of the mobile off-highway market as well as the marine sector. Building on our extensive applications expertise, we work closely with you to ensure exceptional performance for a broad range of applications. We help you and other customers around the world speed up system development, reduce costs and bring vehicles and vessels to market faster.
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