Product Overview
The L2F Series bent-axis fixed displacement axial piston motor is a classic fixed displacement axial piston motor platform from Liyuan Hydraulic, featuring an axial tapered piston rotary group of bent-axis design suitable for hydrostatic drives in both open and closed circuits. The series spans displacements from 12 to 250 cm³/rev, with a nominal pressure of 32 MPa, renowned for its fixed displacement design, structural simplicity, and stable operation in construction machinery, industrial hydraulic systems, and mobile equipment.
The specific models covered in this document — L2F12R2P4, L2F12L4P4, L2F63, L2F80, L2F107, L2F125, L2F160, and L2F250 — span the core displacement range of the L2F Series from 12 cm³/rev to 250 cm³/rev. All models are manufactured to original Liyuan Hydraulic specifications with 100% drop-in interchangeability, requiring no modification to mounting interfaces, port positions, or hydraulic connections. Every unit undergoes 100% simulated operating condition testing at the factory, including rated pressure loading, volumetric efficiency verification, seal integrity assessment, and low-speed smoothness validation prior to shipment.
Technical Specifications
L2F12R2P4 / L2F12L4P4:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 12 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
Approximate weight: 6 kg
L2F63:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 63 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
L2F80:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 80 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
L2F107:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 107 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
L2F125:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 125 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
L2F160:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 160 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Volumetric efficiency: 96%
Overall efficiency: 95%
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
L2F250:
Series / Type: Liyuan L2F Series bent-axis fixed displacement axial piston motor
Displacement: 250 cm³/rev
Nominal pressure: 32 MPa (320 bar)
Material: Cast iron
Operating fluid: Hydraulic oil
Operating temperature: 30–90°C
Mounting: Flange mount
Direction of rotation: Bidirectional
Note: Technical data above is sourced from Liyuan Hydraulic official product information and authorized distributor specifications. The L2F Series covers displacements from 12 to 250 cm³/rev with a nominal pressure of 32 MPa. In motor mode, output speed is proportional to input flow and inversely proportional to displacement; output torque is closely related to the pressure differential between high-pressure and low-pressure sides, with greater differential producing higher torque. For precise technical specifications, always confirm against the Liyuan Hydraulic official technical manual or the product nameplate.
Key Technical Advantages
1. Bent-Axis Axial Tapered Piston Rotary Group Design
The L2F Series employs an axial tapered piston rotary group of bent-axis design, with piston force applied directly to the output shaft socket through spherical piston ends — the torque transmission path is the shortest with high mechanical efficiency. Compared to swashplate designs, the bent-axis architecture accommodates higher working pressures at equivalent displacement and generates lower side forces between pistons and cylinder bores, reducing friction losses and wear rates. Motor output speed is proportional to input flow and inversely proportional to displacement, providing clear parameter matching for system design.
2. Spherical Flow Distribution for High Volumetric Efficiency
The L2F Series employs spherical flow distribution, with the cylinder barrel and valve plate self-aligning during rotation at low circumferential velocity for high efficiency. A stable oil film is maintained between the valve plate and cylinder barrel face under high pressure to preserve high volumetric efficiency (up to 96%) and minimize internal leakage. This design maintains high efficiency across a wide temperature and pressure envelope, minimizing energy loss and heat generation from internal leakage.
3. Fixed Displacement Design for System Simplification
The L2F Series features a fixed displacement design, with core advantages of constant displacement, simple control logic, and stable operation. In hydraulic systems, fixed displacement components require no complex variable adjustment mechanisms, reducing system integration complexity and eliminating maintenance risks from adjustment mechanism wear or failure. For equipment requiring stable speed output, as long as supply flow remains stable, the motor achieves smooth operation.
4. Radial Load Capability and Low Noise Operation
The L2F Series drive shaft is capable of withstanding radial loads, allowing direct mounting of gears, sprockets, or pulleys without requiring a separate bearing support housing — simplifying system design and reducing installation costs. Meanwhile, the spherical flow distribution design and precision-machined rotary group ensure low noise operation, improving the working environment for operators.
5. Cast Iron Housing with High Structural Load Capacity
The L2F Series employs a high-strength cast iron housing with excellent strength and wear resistance, capable of reliable long-term operation under high pressure and temperature conditions. Cast iron offers a low coefficient of thermal expansion, maintaining dimensional stability of the housing under temperature fluctuation conditions and ensuring the fit precision of internal running gear. The compact bent-axis structure achieves high power density within a limited envelope.
Application Areas
Construction equipment: Excavator, loader, and dozer swing drives and travel systems
Lifting and transport machinery: Winch and hoist drives; the L2F250 has been applied in cutter suction dredger hydraulic ladder winches
Mining machinery: Mining drills, crushers, and hoist drives
Agricultural machinery: Combine harvesters, tractors, and corn harvester hydraulic systems; the L2F80 has been successfully applied in corn harvester hydraulic systems
Industrial hydraulic systems: Machine tools, forging equipment, rolling mill auxiliary drives
Marine and offshore: Deck machinery, windlass drives, fishing vessel winches
Specialty vehicles: Transit mixer drum drives, aircraft tractors
Expert Maintenance Tips
1. Fluid Cleanliness Management Is the Primary Task
The L2F Series operates with micron-level clearances between pistons and cylinder bores and between the valve plate and cylinder barrel face. Particulate contamination in hydraulic fluid is the leading cause of piston scoring and valve plate wear. Systems must be equipped with filtration rated to ISO 4406 18/16/13 or better. In dusty construction machinery environments, consider shortening fluid change intervals to 1,000–2,000 hours or every six months.
2. Case Drain Line Configuration Requirements
Case drain from the L2F motor must be routed to the reservoir through the highest drain port, with case pressure strictly controlled within specified limits. Excessive case pressure will cause shaft seal failure; insufficient pressure will reduce lubrication and heat rejection effectiveness. The case drain line must terminate below the minimum oil level in the reservoir to maintain positive return flow under all operating conditions.
3. Pre-Start Case Filling and Air Purging
Before first startup after installation or repair, the motor case must be filled with clean hydraulic fluid through the highest case port until fluid overflows. The L2F bent-axis axial piston architecture creates a complex internal case cavity geometry; starting an un-purged motor can cause dry friction damage between piston ball ends and socket bushings, leading to irreversible premature wear.
4. Output Shaft Spline and Mounting Alignment
The L2F Series uses flange mounting. During installation, verify that the output shaft spline is properly aligned with the mating component, and that spline engagement length meets design requirements. Installation misalignment will cause abnormal spline wear and bearing side loading, significantly shortening service life. Tighten mounting bolts in stages to the specified torque value and re-check torque after 500 operating hours.
5. Restart Procedure After Extended Shutdown
If the motor has been idle for more than three months, manually rotate the output shaft to confirm freedom of movement, and inspect the case oil level and shaft seal for leakage before restarting. Extended shutdown can cause oil film drainage from piston-slipper interfaces, creating a dry-start risk. Before restarting, replenish clean hydraulic fluid through the case fill port and operate at low speed and reduced load for 10–15 minutes before returning to normal duty.
