MK35-2-121-A18 Poclain Motor | 450 Bar 4198cc Wheel Drive

Product Overview

The MK35-2-121-A18-1140-7000 is a dual-displacement radial piston hydraulic motor from Poclain Hydraulics’ MK series of ultra-compact direct drive motors, belonging to the MK35 large frame size. The MK series is Poclain’s ultra-compact direct-drive motor line engineered for space-constrained applications, featuring an ultra-short axial design and large diameter 4-contact roller bearing. The range covers displacements from 272 to 2812 cc/rev with up to 70 kW power, 450 bar maximum pressure and 160 rpm maximum speed—ideal for wheel-drive and road roller vibration shaft applications.

The MK35 series is the large frame offering in the MK compact motor family, delivering maximum displacement of 4198 cc/rev (MS35 series), maximum torque of 30000 N·m, maximum power of 110 kW and maximum pressure of 450 bar, with a multi-speed concept reaching up to 140 rpm. The MK35 series is designed specifically for road rollers, featuring internal curve radial piston design with low noise operation, while also serving construction equipment, material handling, agriculture, mining, rail, marine and industrial markets. The series features a large diameter 4-contact roller bearing capable of directly handling wheel and vibration shaft radial loads without additional bearing support.

The model code breaks down as follows: MK35 identifies the MK series 35 frame size; 2 denotes dual displacement configuration; 121 is the flow-distribution/function module code; A18 is the motor endcap and mounting configuration code; 1140 is the axial/radial large bearing load-bearing output module code; 7000 denotes additional options. Per Poclain’s naming convention, A18 indicates the motor endcap configuration and 1140 indicates the axial/radial large bearing load-bearing output module, ensuring the motor can withstand high axial and radial loads.

Every unit undergoes 100% simulated operating-condition bench testing prior to shipment. Mounting flange, shaft end and port dimensions match the original Poclain MK35 series exactly, enabling true drop-in interchangeability with zero modification required.

Technical Specifications

MK35/MS35 Series Frame Size Specifications:

• MS35-8: Full displacement 2439 ml/r (148.8 cu.in/rev), half displacement 1220 ml/r (74.4 cu.in/rev), theoretical torque at 10 MPa 3878 N·m, max power 110 kW, max speed 140 rpm

• MS35-9: Full displacement 3143 ml/r (191.8 cu.in/rev), half displacement 1572 ml/r (95.9 cu.in/rev), theoretical torque at 10 MPa 4997 N·m, max power 110 kW, max speed 140 rpm

• MS35-0: Full displacement 3494 ml/r (213.2 cu.in/rev), half displacement 1747 ml/r (106.6 cu.in/rev), theoretical torque at 10 MPa 5555 N·m, rated pressure 25 MPa, max pressure 40 MPa, max power 110 kW, max speed 140 rpm

• MS35-1: Full displacement 3836 ml/r (234.1 cu.in/rev), half displacement 1918 ml/r (117.0 cu.in/rev), theoretical torque at 10 MPa 6099 N·m, max power 110 kW, max speed 140 rpm

• MS35-2 (This Model Series): Full displacement 4198 ml/r (256.2 cu.in/rev), half displacement 2099 ml/r (128.1 cu.in/rev), theoretical torque at 10 MPa 6675 N·m, max power 110 kW, max speed 140 rpm

MK35/MS35 Series Common Specifications:

• Series Max Displacement: 4198 cc/rev (256.2 cu.in/rev)

• Series Max Torque: 30000 N·m (22126 lb-ft)

• MK Series Max Pressure: 450 bar (6527 psi)

• MS35 Rated Pressure: 400 bar (5000 psi)

• MS35 Max Continuous Pressure: 250 bar (MS version) / 300 bar (MSE version)

• Series Max Power: 110 kW (148 HP)

• Series Max Speed: 140 rpm (MS35) / 160 rpm (MK series)

• Type: Radial piston LSHT hydraulic motor (internal curve cam ring design)

• Bearing Type: Large diameter 4-contact roller bearing

• Control: Single or dual displacement (multi-speed concept)

• Brake: Service brake, parking brake and hydrostatic boosted brake options

• Motor Type: Wheel motor / shaft motor (modular)

• Anti-Skid Option: TwinLock™ integrated anti-skid available

• Original Design: Poclain Hydraulics, France

MK35-2-121-A18-1140-7000 Additional Specifications:

• Model Code: MK35-2-121-A18-1140-7000

• Type: Compact radial piston motor, internal curve cam ring design

• Displacement: 4198 ml/r (256.2 cu.in/rev) full / 2099 ml/r (128.1 cu.in/rev) half

• Displacement Ratio: 2:1

• Theoretical Torque at 10 MPa: 6675 N·m (full displacement)

• Max Torque: 30000 N·m (22126 lb-ft)

• Max Working Pressure: 450 bar (6527 psi)

• Rated Working Pressure: 400 bar (5000 psi)

• Max Power: 110 kW (148 HP)

• Max Speed: 140 rpm (at max displacement)

• Valving Type: Dual displacement valving module (121 code)

• Mounting Flange: A18 motor endcap configuration

• Output-End Configuration: 1140 axial/radial large bearing load-bearing output module

• Bearing Type: Large diameter 4-contact roller bearing

• Parking Brake Torque: 33000 N·m (24340 lb-ft, with 0 bar in housing, new brake)

• Emergency Dynamic Braking Torque: 21450 N·m (15820 lb-ft, max 10 emergency braking operations)

• Brake Release Pressure Range: 16–30 bar (232–435 PSI)

• Brake Release Capacity: 320 cm³ (19.5 cu.in)

• Anti-Skid Option: TwinLock™ available

• Motor Type: Wheel motor

• Operating Temperature Range: -40°C to +115°C

• Hydraulic Fluid: Mineral oil (ISO VG46/68), synthetic oil, water glycol

• Original Design: Poclain Hydraulics, France

Key Technical Advantages

1. Low Noise Radial Piston Design for Quiet and Smooth Operation

The MK35-2-121-A18 employs Poclain’s patented internal curve radial piston design, with multiple pistons arranged radially around a cam ring to deliver high torque at extremely low speeds. The design features significantly low noise characteristics—MS/MSE radial piston high-torque cam motors are renowned for high pressure, high efficiency and very little noise output. With theoretical torque of 6675 N·m at 10 MPa and maximum torque of 30000 N·m at full displacement, the motor operates smoothly across the 0–140 rpm speed range without stick-slip.

2. Ultra-Compact Direct Drive Design with Large Diameter 4-Contact Roller Bearing

The MK35-2-121-A18 features Poclain MK series’ signature ultra-short axial design with a large diameter 4-contact roller bearing (1140 output module) capable of directly handling wheel and vibration shaft radial loads without additional bearing support. This makes it an ideal choice for road roller vibration shaft coaxial drives. The MK series’ large central hollow shaft makes it particularly suited for mounting on vibratory equipment.

3. Innovative Valving Design Reducing Pressure Drop by Over 50%

The MS35/MK35 series integrates a new valving design that reduces pressure drop by over 50%, directly increasing efficiency even at low speeds. At comparable output levels, overall machine energy consumption is significantly reduced, delivering substantial energy savings. This makes the MK35-2 particularly advantageous in heavy road rollers and construction equipment requiring extended continuous operation.

4. Modular Architecture with TwinLock™ Anti-Skid System

The MK series employs Poclain’s modular design concept, allowing displacement group, flow-distribution module, brake module and output-end module to be reconfigured. The A18 motor endcap combined with the 1140 axial/radial large bearing output module supports wheel-drive mounting. Optional TwinLock™ integrated anti-skid provides differential locking via hydraulic control for improved traction. Brake options include service brake, parking brake and hydrostatic boosted brake modules.

5. 100% Simulated Load Testing & Drop-In Interchangeability

Each MK35-2-121-A18-1140-7000 unit is bench-tested under simulated operating conditions prior to dispatch, covering pressure cycling, speed shifting, brake performance and thermal variation. Mounting flange, shaft end and port dimensions match the original Poclain MK35 series exactly, enabling direct replacement without pipework or interface modification. Motor performance is very close to original Poclain motors, with both complete motors and spare parts 100% interchangeable.

Application Areas

The MK35 series is designed specifically for road rollers and is also widely deployed across the following:

• Road Rollers: double drum asphalt roller vibration shaft coaxial drives, single drum roller wheel drives (Poclain is the market benchmark for double drum roller hydrostatic transmission)

• Construction: large wheel loaders (Caterpillar 980H/988K, Volvo L220H/L260H, Komatsu WA600/WA700, Liebherr L566/L580, Hitachi ZW310/ZW370)

• Agriculture: large tractors (John Deere 9570RX/9620RX, Case IH Steiger 540/620, New Holland T9.700, Fendt 1100 Vario MT, Claas Xerion 5000/4500)

• Self-Propelled Sprayers: Agrifac Condor Endurance, Amazone Pantera 7004, Hardi Alpha 5100

• Mining: large mining truck auxiliary drives, subsurface loaders

• Marine & Offshore: deck machinery, winch drives

• Industrial: large shredders, industrial conveyors, mill drives

Expert Maintenance Tips

1. Brake Running-In and Release Pressure Verification: The integrated parking brake on the MK35-2-121-A18 provides 33000 N·m (24340 lb-ft) of braking torque with a release pressure range of 16–30 bar (232–435 PSI). Running-in is required after installation. Abnormally high release pressure typically indicates friction plate wear or piston seal failure—replace promptly. Emergency dynamic braking torque is 21450 N·m with a maximum of 10 emergency braking operations, after which service should be scheduled promptly.

2. Dual Displacement Valving Module Maintenance: The dual displacement valving module is controlled by pilot pressure. If shift response is sluggish or excessively harsh, inspect the pilot control spool for sticking and the flow-distribution shaft O-rings for aging. Shift operations should be performed at low speed or standstill to avoid impact loading on the distribution mechanism. Inspect pilot control pressure and valving module seal condition every 1,000 hours.

3. Mounting Flange and Large Bearing Inspection: The MK35-2-121-A18 features the A18 motor endcap with the 1140 axial/radial large bearing output module. Periodically inspect the output flange plane and wheel/vibration shaft mating surface for wear or deformation. Ensure flange mating surface parallelism deviation does not exceed 0.05 mm during installation, and tighten bolts evenly in a diagonal sequence to Poclain technical manual torque values. Mounting surface flatness requirement is 0.2 mm with Ra 12.5 μm surface roughness.

4. Oil Cleanliness and Temperature Control: Maintain system oil cleanliness at ISO 4406 18/16/13 or better. HV46 hydraulic oil is recommended. Operating oil temperature should be kept below 80°C; elevated temperatures accelerate brake friction plate and seal degradation. Replace hydraulic oil and filter after the first 500 hours, then follow a 2,000-hour or annual replacement cycle. System temperature must not exceed 115°C at any point.

5. Drain Line Management and Housing Priming: The drain port must return to the reservoir independently—housing back pressure must not exceed 2 bar. The drain line end must remain submerged to prevent air ingestion. Fill the housing with clean hydraulic oil before first startup. After extended shutdown, fill the housing again before restarting. Brake release capacity is 320 cm³—ensure the brake chamber is filled with clean hydraulic oil during initial priming.

6. Periodic Piston Group and Cam Ring Inspection: As a radial piston motor, the MK35-2-121-A18’s primary wear points are the piston rollers and cam ring contact surface. Inspect piston roller wear and cam ring working surface every 2,000 hours. Both displacement cam surfaces require inspection. Abnormal noise or efficiency loss requires immediate shutdown and service. Use Poclain original specification parts when replacing piston groups to ensure fit accuracy and assembly torque per technical manual requirements.

7. Modular Repair Strategy: The MK series modular design allows replacement of individual worn modules rather than the entire motor. Establish a modular spare parts inventory including flow-distribution module seals, piston groups, cam rings and brake friction plates to minimize machine downtime. When replacing modules, follow Poclain official technical manual torque values and assembly sequences.