Analysis of the normal torque range of hydraulic gear oil pump bolts

A、 Core influencing factors of bolt torque in gear oil pump 1. Sealing requirements: When the oil pump joint surface needs to prevent leakage, the torque should be increased by 10% -15% to ensure that the sealing gasket is tightly pressed, but it should not exceed the yield strength of the bolt. 2. Material strength: The material of the bolt (such as 8.8 grade, 10.9 grade carbon steel or stainless steel) directly determines the maximum allowable torque. For example, the standard torque for M10 grade 8.8 bolts is 45-50 N · m, while grade 10.9 can reach 70-75 N · m (refer to ISO 898-1 standard). 3. Working conditions: Vibration and temperature changes may cause loosening. It is recommended to use thread glue or anti loosening gaskets and tighten them regularly.

B、 Practical suggestions and precautions Step by step tightening: It is recommended to tighten 2-3 times in a diagonal order to avoid uneven force distribution. For example, the M8 bolt is first pre tightened to 15 N · m, and then gradually increased to 30 N · m. 2. Tool selection: Priority should be given to using a digital torque wrench, with an error controlled within ± 3%. 3. Maintenance check: After running for 100 hours, it needs to be tightened again, and the torque attenuation should be checked every 500 hours thereafter.

C、 Expansion: Consequences of insufficient or excessive torque -Insufficient torque: Oil leakage on the joint surface, loosening and detachment of bolts, leading to increased vibration of the pump body. -Excessive torque: Thread slippage or pump casing cracking significantly increases maintenance costs. Based on the above analysis, users can flexibly adjust the torque value according to specific models and working conditions to ensure the long-term stable operation of the gear oil pump.

The above：Reason analysis and solution for the fracture of the front cover of hydraulic gear pump in construction machinery