HITACHI Hydraulic Pump Parts

Hydraulic Pump: generates the hydraulic pressure needed to operate the various functions of the excavator.
Component of Hydraulic Pump: Rotor, Valve Plate, Shoe plate, drive shaft, gear pump, bearing, swash plate, piston, set plate and ball guide.

1. Pump Housing

• Material: High-strength alloy
• Function: Encases and protects internal components

2. Drive Shaft

• Material: Hardened steel
• Function: Transmits mechanical power from the engine to the pump

3. Swash Plate

• Function: Adjusts the angle of the pistons' stroke to control the hydraulic fluid flow rate

4. Cylinder Block (Rotating Group)

• Function: Houses multiple pistons and rotates with the drive shaft

5. Pistons

• Material: Hardened steel or alloy
• Function: Move back and forth within the cylinder block to create hydraulic pressure

6. Valve Plate

• Function: Directs the flow of hydraulic fluid into and out of the pump chambers

7. Retainer Plate

• Function: Holds the pistons in place and ensures their proper alignment

8. Thrust Plate

• Function: Provides a surface for the pistons to push against, converting rotational motion into linear motion

9. Shoe Plate and Piston Shoes

• Function: Attach to the ends of the pistons and slide along the swash plate

10. Center Pin

• Function: Aligns and supports the rotating group

11. Return Plate

• Function: Ensures that pistons return to their starting position

12. Bearing

• Types: Radial and axial bearings
• Function: Support the rotating shaft and reduce friction

13. Port Plate

• Function: Manages the flow of hydraulic fluid between the pump and the external hydraulic system

14. Servo Piston

• Function: Adjusts the angle of the swash plate for variable displacement control

15. Control Valve (Servo Valve)

• Function: Regulates the hydraulic fluid flow to the servo piston, controlling pump output 

16. Seal Kit

• Function: Includes various seals and O-rings to prevent leaks

17. Back Plate

• Function: Provides support and structure to the assembly

18. End Cover

• Function: Seals the back of the pump and houses various internal components

19. Charge Pump (Optional)

• Function: Maintains the necessary pressure in the pump to ensure proper operation

20. Rotating Group

• Function: Includes the cylinder block, pistons, and drive shaft, all working together to create hydraulic pressure
  
• These components work together to ensure the efficient operation of the hydraulic pump, which is widely used in construction machinery such as excavators.