25SCY14-1B Manual Variable Axial Piston Pump 25cc 31.5MPa

Product Overview

The 25SCY14-1B is a manual variable axial piston pump from the CY14-1B series, with a nominal displacement of 25 mL/r and rated pressure of 31.5 MPa. The pump features a valve-plate distribution, rotating cylinder barrel design. Flow rate is adjusted by turning a handwheel, which moves the variable piston and changes the tilt angle of the variable head (swashplate), thereby varying the piston stroke length. Turning the handwheel clockwise decreases flow; turning it counter-clockwise increases flow. The flow percentage can be roughly read from the dial, and a lock nut secures the setting once the desired flow is reached. This variable type is suitable for applications requiring infrequent adjustment and no remote operation.

The CY14-1B series axial piston pumps employ hydrostatic balance structures between the slipper and variable head, and between the valve plate and cylinder barrel, enabling critical running surfaces to operate under pure liquid friction. This results in simple structure, compact size, high efficiency, long service life, lightweight design, and strong self-priming capability. The drive shaft rotates the cylinder barrel, causing seven evenly distributed pistons to revolve about the shaft centerline. A central spring presses the slipper pads against the variable head (swashplate), and the pistons reciprocate as the cylinder barrel rotates to perform suction and pressure strokes.

The pump is widely used in hydraulic transmission systems of machine tools, forging, metallurgy, engineering, and mining machinery, delivering hydraulic oil at 31.5 MPa to generate working power. It can also be used as a hydraulic motor by replacing the motor valve plate. The pump shares the same mounting flange and shaft extension standards with YCY14-1B (constant horsepower variable) and MCY14-1B (fixed displacement) models, providing flexible selection options.

Manufactured to exact CY14-1B series specifications, all mounting dimensions, flange interfaces, and port layouts are fully consistent with the original pump for true drop-in interchangeability. Every unit undergoes 100% simulated operating condition testing before shipment.

Technical Specifications 

• Model: 25SCY14-1B

• Series: CY14-1B Series

• Pump Type: Manual variable axial piston pump, swashplate design, rotating cylinder barrel

• Control Type: Manual variable (handwheel adjusts screw, changing swashplate angle)

• Nominal Displacement: 25 mL/r

• Rated Pressure: 31.5 MPa (315 bar)

• Maximum Pressure: 35 MPa (350 bar)

• Nominal Speed: 1500 rpm (10–160 mL/r); 1000 rpm (250 mL/r and above)

• Theoretical Flow (1000 rpm): 25 L/min

• Theoretical Flow (1500 rpm): 37.5 L/min

• Maximum Transmission Power: 14.1 kW

• Maximum Theoretical Torque: 134.9 N·m

• Number of Pistons: 7

• Rotation Direction: Clockwise (viewed from shaft end); unmarked indicates standard forward rotation

• Recommended Hydraulic Fluid: N46 anti-wear hydraulic oil

• Fluid Temperature Range: Optimal 30°C–55°C; must not exceed 60°C

• Volumetric Efficiency: ≥ 92%

• Housing Material: Cast iron

Key Technical Advantages

1. Manual Variable Handwheel Control for Precise Flow Adjustment: The defining technical feature of the 25SCY14-1B is its manual variable control. Turning the adjustment handwheel rotates the adjustment screw, driving the variable piston axially and rotating the variable head about its center to change the tilt angle, thereby varying flow. Turning the handwheel clockwise decreases flow; counter-clockwise increases flow. The flow percentage can be roughly read from the dial. A lock nut secures the setting once the desired flow is reached. This control type offers simple structure and intuitive operation, suitable for infrequent adjustment applications.

2. Hydrostatic Balance Structure Reduces Wear: Hydrostatic balance design is employed between the slipper and variable head, and between the valve plate and cylinder barrel. High-pressure oil forms hydrostatic films on the slipper underside and valve plate back surface, enabling critical running surfaces to operate under pure liquid friction with minimal mechanical wear. This design maintains stable volumetric efficiency during long-term continuous operation at 31.5 MPa, with volumetric efficiency of not less than 92%.

3. Spherical Valve Plate Distribution with Automatic Self-Centering: The cylinder barrel and valve plate employ a spherical distribution structure, enabling automatic self-centering during rotation, with low stable speed, low noise, and long service life. The central spring presses the slipper pads against the variable head, providing initial sealing to ensure immediate seal establishment at startup and prevent dry friction.

4. CY14-1B Series Platform Drop-In Interchangeability: The 25SCY14-1B’s mounting flange, shaft extension dimensions, and port layout fully comply with CY14-1B series standards. The CY14-1B series covers displacements from 1.25 to 400 mL/r, with high consistency in mounting interfaces across sizes within the series. No coupling, piping, or mounting base modification is required for replacement — dramatically reducing equipment downtime.

5. Shared Mounting Dimensions with Variable Pump Platforms: SCY14-1B (manual variable), YCY14-1B (constant horsepower variable), MCY14-1B (fixed displacement), and PCY14-1B (constant horsepower variable) share the same mounting flange and shaft extension standards. During equipment modification or process changes, users can flexibly select pumps with different control types under the same mounting interface without replacing piping or couplings, significantly reducing modification costs.

Application Areas

• Machine Tools: Planer-type milling machines, broaching machines, grinding machines — hydraulic power units requiring manual flow adjustment

• Forging Equipment: Hydraulic presses, stamping presses, bending machines

• Metallurgical Machinery: Rolling mill auxiliary hydraulics, continuous casting equipment

• Mining Machinery: Mine hoisting equipment, underground drilling rig hydraulic drives

• Marine Hydraulics: Ship steering gear, deck machinery hydraulic power sources

• Construction Machinery: Cranes, excavators — auxiliary hydraulic systems

• Hydraulic Motor Applications: Can be used as hydraulic motor by replacing motor valve plate

Expert Maintenance Tips

1. Shaft Alignment and Flange Connection: Concentricity deviation between the pump and drive shaft must be less than 0.05 mm, with angular deviation less than 0.25°. The SCY14-1B uses CY14-1B series standard mounting flange. Tighten flange bolts in diagonal sequence for even loading. Clean preservative grease from the pump housing and tighten all connection bolts before installation.

2. Initial Start-Up Filling and Bleeding: Pre-fill the pump with clean N46 anti-wear hydraulic oil through the case drain port before installation — startup without pre-filling is strictly prohibited. Start at the lowest drive speed and observe a steady oil flow from the case drain port free of bubbles. Run unloaded for 10–15 minutes to expel air before gradually applying pressure.

3. Manual Variable Adjustment Operation: Reduce system load before adjusting flow. Turn the handwheel to move the variable piston and change the variable head tilt angle. Clockwise rotation decreases flow; counter-clockwise increases flow. Tighten the lock nut once the desired flow is reached. Avoid forced adjustment under load to prevent damage to the variable mechanism.

4. Rotation Direction Verification: The standard configuration is clockwise rotation (viewed from shaft end). Driving it counter-clockwise is strictly prohibited — incorrect drive direction will reverse the suction and pressure sides, causing severe rotating group damage within a short period.

5. Fluid Temperature and Cleanliness Management: Use N46 anti-wear hydraulic oil. Optimal oil temperature is 30°C–55°C; reservoir oil temperature must not exceed 60°C. Pipelines must be strictly cleaned before installation. For newly commissioned equipment, clean the reservoir and replace oil after approximately one month, then every 1–6 months thereafter. Do not install a strainer or filter at the pump inlet — filters can be installed in the reservoir or at the outlet.

6. Case Drain Line Configuration: The case drain line must return directly to the reservoir with backpressure not exceeding 2 bar. Pre-fill the pump through the drain port before use to prevent instantaneous wear from oil starvation.