Product Overview
The HMR135-02 belongs to the HMR-02 series of swashplate axial piston variable displacement hydraulic motors/pumps, originally designed by Linde and now part of the Parker Hannifin hydraulic transmission platform. The HMR-02 series offers multiple displacement options from 55 to 210 cc, covering applications from light-duty to heavy-duty mobile and industrial equipment. This product covers the HMR135-02 model (part number 5469661257 / 2584) with 135.6 cc displacement — the medium-displacement主力 model within the HMR-02 series.
Product Positioning Note: The HMR series core product is a hydraulic motor featuring swashplate axial piston design with an integrated pressure regulator. The product is also adaptable for pumping applications and operates in both open and closed circuits. The HMR135-02 is widely used in swing and traction drive systems of premium mobile equipment including Volvo EW160B/EW180B/EW200B wheeled excavators, Cat M315/M318/M320, and Liebherr PR 734 bulldozers.
100% Interchangeability Guarantee: Our products strictly adhere to Linde/Parker HMR-02 original mounting dimensions and port layouts, enabling drop-in replacement without modifications to existing piping or brackets. Every unit undergoes 100% simulated duty-cycle testing under actual load conditions to validate performance parameters before shipment, ensuring immediate reliability upon installation.
Quality & Manufacturing Standards: The housing is manufactured from high-strength cast iron, with critical tribological pairs (cylinder barrel/valve plate, pistons/slippers) precision-ground and heat-treated. Slippers are standardized and interchangeable with HMV135-02 and HPV135-02 components. Premium-grade bearings ensure long service life and reliable operation under 500 bar peak pressure and high-speed conditions.
Technical Specifications
Series General Specifications (HMR-02 Family):
Design: Swashplate axial piston variable displacement motor/pump
Circuit Type: Suitable for both open and closed circuits
Rated Pressure: 420 bar / 450 bar (alternate sources)
Peak Pressure (intermittent): 500 bar
Control: Integrated pressure regulator — no external control lines required
Mounting Flange: SAE mounting flange
Main Ports: SAE high-pressure ports, radial or axial orientation optional
Through-Drive: PTO through-drive capable, power output at both ends
Optional Features: Flush valves, cross relief valves, counterbalance valve (CBV), speed sensors, maximum displacement lock (pneumatic/hydraulic/electric)
HMR135-02:
Model Code: HMR135-02 (Part No. 5469661257 / 2584)
Maximum Displacement: 135.6 cm³/rev (8.27 in³/rev)
Rated Pressure: 450 bar (6,527 psi)
Peak Pressure (intermittent): 500 bar (7,252 psi)
Maximum Operating Speed @ Vmax: 3,200 rpm
Maximum Operating Speed @ Vmin (intermittent): 4,000 rpm (3,700 rpm per alternate sources)
Maximum Output Torque (@ Δp=430 bar): 928 N·m
Continuous Output Torque: 540 N·m
Maximum Output Torque: 907 N·m
Continuous Power: 181 kW
Maximum Power: 304 kW (311 kW / 360 kW per alternate sources)
Weight (approx.): 56 kg
Key Technical Advantages
1. Integrated Pressure Regulator — No External Control Lines Required
The HMR135-02 features an integrated pressure regulator — displacement is automatically adjusted by system pressure without the need for external control valves or pilot lines. As system pressure varies, the motor automatically adjusts displacement to match load torque and speed requirements, significantly simplifying hydraulic system architecture and reducing installation and maintenance costs.
2. Excellent Low-Speed Stability and High Starting Torque
The HMR-02 series is optimized for superior starting and low-speed characteristics. Smooth operation is maintained even at very low speeds, with starting torque reaching 90%-95% of theoretical values. This makes it particularly suitable for applications requiring precise positioning and smooth starts, such as swing systems on wheeled excavators.
3. High Power Density and Compact Design
The HMR135-02 delivers up to 304 kW of power output within a compact envelope, offering an exceptional power-to-weight ratio. SAE standard mounting flange and radially/axially orientable SAE high-pressure ports provide equipment manufacturers with exceptional layout flexibility.
4. High Volumetric Efficiency and Long-Term Reliability
Precision-ground cylinder barrel/valve plate tribological pairs and optimized internal leakage control strategies deliver exceptional volumetric efficiency (up to 98%). High-strength cast iron housing, high-capacity bearings, and precision heat-treated piston/slipper assemblies ensure long-term reliability under 500 bar peak pressure. Slipper standardization with HMV135-02/HPV135-02 components further reduces spare parts inventory costs.
5. Flexible Through-Drive and Extensive Optional Configurations
The HMR135-02 supports through-drive design, enabling tandem mounting of additional pumps or motors on the same axis with power output at both ends. Optional features include flush valves, cross relief valves, counterbalance valves (CBV), speed sensors, and pneumatic/hydraulic/electric maximum displacement locks — meeting customization requirements for diverse complex systems.
Application Areas
The HMR135-02 swashplate axial piston variable motor/pump is widely deployed in closed and open-circuit hydraulic drive systems across the following mobile equipment categories:
Wheeled Excavators — swing drive and traction drive
Bulldozers — traction drive
Asphalt Pavers — traction drive and material conveying
Rollers / Compactors — traction drive and vibration systems
Forestry Machinery — winch and traction drives
Combine Harvesters & Agricultural Machinery — hydrostatic drives
Concrete Mixers — drum drive
Cranes and Material Handling Equipment — slewing and traction drives
Expert Maintenance Tips
1. Housing Priming Before Installation (Critical Step)
Before initial start-up or after extended downtime, the housing must always be filled with hydraulic fluid. Pre-fill through case drain ports prior to start-up. For vertical installations with the input shaft pointing upward, purge air through the D1 drain port located near the mounting flange. Dry-running at start-up will cause irreversible damage to critical tribological pairs (cylinder barrel/valve plate, pistons/slippers).
2. Filtration and Fluid Cleanliness Requirements
Axial piston motors are highly sensitive to fluid cleanliness. Recommended filtration per ISO 4406 cleanliness level of 19/17/14 or better. Return line and suction filters should be inspected and replaced regularly. Optional flush valves help continuously exchange hot oil in closed circuits, maintaining fluid cleanliness and operating temperature.
3. Pressure Setting and System Matching
The HMR135-02 employs an integrated pressure regulator for displacement control. After system installation, correctly set pressure limits per the technical manual to ensure they do not exceed the 500 bar peak pressure threshold. Prior to initial loading, run at low speed with no load for 5–10 minutes to purge air and establish proper oil film before gradually applying load.
4. Through-Drive Tandem Installation Considerations
For multiple pump/motor tandem installations (through-drive), arrange the highest power flow unit closest to the input power source. Ensure all case drain ports in the tandem stack have unrestricted return paths to prevent case pressure exceedance.
5. Counterbalance Valve (CBV) Recommendation
For swing and traction drive applications requiring braking or anti-runaway functionality, the counterbalance valve (CBV) is strongly recommended. The CBV provides hydraulic braking in the event of system pressure loss, preventing uncontrolled load descent and significantly enhancing operational safety.
