In the bearing production process, the most critical links are as follows:
1. Precision machining and tolerance control
Core component processing:
Plunger/cylinder block (piston pump): The machining accuracy of the hole position needs to reach the μm level, and the surface roughness should be ≤ Ra 0.4 to ensure tightness and lubricity.
Gears/side plates (gear pumps): The tooth shape error needs to be ≤0.01mm, and the flatness of the side plates is extremely high (usually grinding or grinding processes are required).
Vane groove (vane pump): The tolerance of the groove width should be controlled within ±0.005mm to avoid blade stagnation or leakage.

Means of control:
Use high-precision CNC machines (e.g. Swiss-type CNC, coordinate grinding machines).
Introduce in-line inspection (e.g., pneumatic gauge, laser measurement) to monitor dimensions in real time.
Statistical Process Control (SPC) was applied to analyze the machining stability.
2. Material selection and heat treatment
Key Materials:
Housing: high-strength cast iron (e.g. HT300) or aluminum alloy (lightweight required).
Friction pair (e.g. plunger-cylinder block): case hardened steel (e.g. 20CrMnTi carburizing and quenching) or copper alloy coating.
Bearings/gears: High carbon chromium steel (GCr15) quenched and tempered + quenched, hardness HRC 58-62.

Heat treatment process:
Vacuum quenching reduces oxidative distortion.
Ion nitriding improves surface hardness and wear resistance (layer depth 0.1-0.3mm).
3, grinding process
Core Requirements:
Coaxiality control: The coaxiality of the assembly of the drive shaft and the bearing is ≤0.02mm (using hydraulic expansion sleeve or hot installation process).
Preload management: The bolt tightening torque should be applied according to the gradient to avoid the squeezing and deformation of the seal.
Clearance adjustment: For example, the gap between the side plate of the gear pump and the end face of the gear (usually 5-15μm) needs to be accurately set by the optional gasket or adjustment screw.