MSF-23 KYB Hydraulic Fan Motor | 245 Bar Variable 3000 RPM

Product Overview

The MSF-23 (part number 10033071 / MA23W01) is a 23 cc/rev displacement model from KYB’s MSF series of swashplate-type variable displacement axial piston motors, developed specifically for hydraulic fan drive systems in construction machinery. The MSF series is KYB’s classic compact swashplate piston motor platform, covering displacements from MSF-12 to MSF-50, featuring variable displacement design for open-circuit hydraulic systems.

This model serves as the original equipment hydraulic fan motor for Sany SY485 and SY550 large crawler excavators, driving the cooling fan to provide forced-air cooling for the engine radiator and hydraulic oil cooler. The MSF-23’s variable displacement characteristic enables automatic fan speed adjustment based on actual engine and hydraulic system temperature requirements, maximizing energy savings while meeting cooling demands.

Every MSF-23 unit undergoes 100% simulated operating-condition bench testing prior to shipment. Mounting flange, shaft end and port dimensions are identical to the original KYB MSF-23, ensuring true drop-in interchangeability with zero modification required.

Technical Specifications

MSF Series Frame Size Specifications:

• MSF-12: Max working pressure 24.5 MPa (245 bar), swashplate type variable piston motor

• MSF-18: Displacement 16.4–18.4 cm³/rev, max working pressure 24.5 MPa (245 bar)

• MSF-23 (This Model): Displacement 23.4 cm³/rev, max working pressure 245 bar (24.5 MPa), max speed 3000 rpm, max flow 70 L/min

• MSF-30: Max working pressure 24.5 MPa (245 bar), swashplate type variable piston motor

• MSF-50: Max working pressure 24.5 MPa (245 bar), swashplate type variable piston motor

MSF-23 Additional Specifications:

• Model Code: MSF-23

• OEM Part Numbers: 10033071 / MA23W01 / VOE14531612 / VOE14542951, etc.

• Type: Swashplate type variable displacement axial piston motor

• Displacement: 23.4 cm³/rev (1.43 in³/rev)

• Maximum Working Pressure: 245 bar (24.5 MPa / 3,553 psi)

• Maximum Speed: 3,000 rpm

• Maximum Flow: 70 L/min

• Control Type: Two-speed variable displacement, swashplate angle switching via variable valve

• 1st Speed (Large Displacement): Swashplate tilts at maximum angle, outputting larger displacement for high cooling demand conditions

• 2nd Speed (Small Displacement): Reduced swashplate angle, outputting smaller displacement for low cooling demand conditions, reducing energy consumption

• Circuit Type: Open circuit

• Mounting: Flange mounting

• Weight: ~50–150 kg (depending on configuration)

• Original Design: KYB, Japan

Key Technical Advantages

1. Swashplate Two-Speed Variable Design for On-Demand Cooling and Energy Saving

The MSF-23 features KYB’s signature swashplate two-speed variable design. When the control valve is switched to 1st speed, the variable valve connects the swashplate control piston chamber with the reservoir, and the swashplate tilts at maximum angle under the driving force of the motor on the piston and the spring on the cylinder block side, outputting maximum displacement to drive the fan at high speed for high cooling demand. When switched to 2nd speed, the control valve leads motor driving pressure to the swashplate control piston, reducing the swashplate angle and outputting smaller displacement, lowering fan speed and significantly reducing energy consumption. This on-demand cooling mechanism substantially reduces hydraulic system energy consumption during low-load excavator operations, improving overall fuel efficiency.

2. Compact and Lightweight Swashplate Design for Easy Installation

The MSF-23 employs a compact, lightweight swashplate axial piston design with small dimensions, facilitating installation in space-constrained environments such as excavator engine compartments. The design balances reliability and durability, achieving efficient and stable operation in a compact package, particularly suitable for hydraulic fan drives in small to medium tracked and wheeled construction machinery.

3. High Pressure Capability and Stable Operation

The MSF-23 supports maximum working pressure of 245 bar (24.5 MPa) with maximum speed of 3,000 rpm and maximum flow of 70 L/min. The high pressure rating enables stable fan drive under high-load excavator conditions, ensuring the engine and hydraulic system remain within optimal operating temperature ranges. The piston design with precision-ground cylinder bores and swashplate surfaces minimizes internal leakage, maintaining high volumetric efficiency across the full speed and pressure range.

4. Wide Equipment Compatibility and OEM Interchangeability

The MSF-23 is the original equipment hydraulic fan motor for Volvo EC160C through EC750D series excavators and Sany SY485, SY550 large crawler excavators. Its OEM part number coverage includes Volvo VOE14531612, VOE14542951 through VOE14542958, SA8230-32410 and Sany 10033071, MA23W01 and other numbers, providing broad equipment compatibility.

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

Each MSF-23 unit is bench-tested under simulated operating conditions prior to dispatch, covering pressure cycling, displacement response and speed stability. Mounting flange, shaft end and port dimensions match the original KYB MSF-23 exactly, enabling direct replacement without pipework or interface modification.

Application Areas

The MSF-23 hydraulic fan motor is widely deployed in cooling systems of the following construction machinery:

• Sany Excavators: SY485C-10H, SY485BH, SY550 large crawler excavator hydraulic fan drives

• Volvo Excavators: EC160C L/NL, EC180C L, EC210C L/LD/LR/N/NL, EC235C LD/NL, EC240B FX/LC/LR/NLC, EC240C L/LD/LR/NL, EC250D L/LR/NL, EC290B FX/LC/LR/NLC, EC290C L/LD/LR/NL, EC300D L/LD/LR/NL, EC700B HR/LC, EC700C HR/L/LD, EC750D L, ECR235C L, ECR235D L, ECR235E L, ECR305C L and more

• Volvo Forestry Machinery: FC2121C, FC2421C, FC2924C, FC3329C forwarders

• Volvo Pipelayers: PL3005D

• Other Construction Machinery: harvesters, road rollers and other tracked and wheeled machinery hydraulic fan drive systems

Expert Maintenance Tips

1. Two-Speed Variable Switching Mechanism Maintenance: The MSF-23’s core advantage is its two-speed variable switching function. Periodically inspect the variable valve operating condition to confirm proper switching response between 1st speed (large displacement) and 2nd speed (small displacement). If switching is sluggish or fails to occur, inspect the variable valve spool for sticking, the swashplate control piston for seal failure and the control circuit for air entrainment. Inspect variable switching mechanism response characteristics every 1,000 hours.

2. Periodic Swashplate and Piston Group Inspection: The swashplate working surface and piston slippers are primary wear components of the MSF-23. Inspect swashplate surface wear, piston slipper wear and cylinder bore clearance every 2,000 hours. Abnormal efficiency loss, noise or unstable fan speed requires immediate shutdown and service. Use KYB original specification parts when replacing swashplate or piston groups to ensure fit accuracy and assembly torque per technical manual requirements.

3. Oil Cleanliness and Temperature Control: Maintain system oil cleanliness at ISO 4406 18/16/13 or better. Operating oil temperature should be kept below 80°C—system temperature must not exceed 115°C at any point. Replace hydraulic oil and filter after the first 500 hours, then follow a 2,000-hour or annual replacement cycle. VG 46 is recommended at 60°C operating temperature.

4. Housing Priming Before First Startup: Before first startup, fill the motor housing with clean hydraulic oil through the drain port. An unprimed housing causes dry friction at startup, severely damaging the piston group and swashplate mechanism. After extended shutdown, fill the housing again before restarting. 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.

5. Complete Fan Drive System Inspection: Periodically inspect fan blades for deformation or damage, and check fan-to-motor shaft connection tightness. Fan imbalance or loose connection causes abnormal bearing wear and vibration. Also inspect coolers and piping for blockage or leakage to ensure overall cooling system operation.