The editor of the walking reducer series will analyze how to judge the walking deviation of an excavator

2025-07-16

How to judge the walking deviation of an excavator

Problem status:

A 20-ton Guo San excavator, which had completed 3,147 hours of work, suddenly experienced a severe deviation in its walking performance.

Problem analysis:

1. Main valve issue (inconsistent displacement of front, rear, left, and right pumps) 2. Main valve issue (travel valve rod, straight travel valve rod) 3. Intermediate rotary joint issue (damaged oil seal, process technology hole plug bolt backed out) 4. Oil motor issue (internal damage, overflow valve, static balance valve stuck) 5. Travel reducer damaged, additional electrical components issue

Problem resolution: ① According to the on-site test drive, the getting-on action was normal, and the left-side walking was normal when walking independently. However, the right-side walking was sluggish and weak. The problem persisted when entering the vehicle and performing straight-line walking tasks with both sides of the walking valve (resolving issues with the main valve, control board, and other electrical components). ② During the single-side propelled right-side walking test with the track off the ground, the pressure of the right-side walking pilot was 39kg, the main pressure was 335kg, and the walking reducer had no abnormal noise (resolving issues with the main valve, pilot valve, intermediate rotary joint, and reducer). ③ During the single-side propelled right-side walking test with the track off the ground, the pressure of the right-side walking pilot was

39kg, main pressure 335kg, no abnormal noise from the travel reducer (solved problems with the main valve, pilot valve, intermediate rotary joint, and reducer) ④ Disassemble the motor baffle. During the test drive of the travel motor, there was a very obvious hydraulic system pulsation when touching the main oil pipe. It is speculated that the static balance valve may not be opened, causing the motor to fail to work. Remove the static balance valve plug and take out the valve core. The surface of the valve core is smooth and flat without damage marks, and the valve core rolls freely on the wall. Upon further analysis of the hydraulic system diagram, it was found that the hydraulic oil must pass through the throttle valves (one on each side of the static balance valve) to drive the valve core to work. Upon inspection, it was found that one of the one-way throttle valves had a metal debris blocking the needle hole. It was impossible to blow through with a mouth, so a steel brush was brought on site and a stainless steel wire was used to remove the metal debris stuck in the throttle hole. The right travel returned to normal

Kunshan Chuanna Hydraulic Fittings Co., Ltd. specializes in wholesale and sales of solenoid valves, hydraulic pumps, SANY excavator parts, traveling reducers, etc. Welcome to inquire.