Fault Analysis and Elimination of Throttle Valve in Hydraulic System (2)

3. Leakage

The external leakage of the throttle valve mainly occurs in the adjustment handle, in addition to the process plug, valve installation surface, etc. The main cause of external leakage is caused by the damage of the sealing device, and corresponding measures can be taken according to the actual situation in actual work.

4. Internal leakage

The main reason for the large internal leakage is that the matching gap between the throttle spool and the valve hole is too large or the wear is serious during use, and there are grooves (especially axial grooves) on the spool and the valve hole, and oil Caused by various factors such as high temperature.

The elimination method is to ensure that the matching gap between the valve core and the valve hole is within the range of 0.007-0.015mm. If the wear is severe or there are grooves in the strain, the valve core needs to be electroplated or reprocessed for grinding and grinding.

5. Repair of throttle valve

(1) Spool

When the valve core with serious wear and tight strain groove needs to be repaired, it can be ground by through grinding method on a centerless grinder to remove 0.05~0.10mm, and then a layer of hard chrome is plated by an electric brush, and then ground by a coreless grinder. , use chromium oxide polishing paste for polishing and repairing.

(2) Valve body

Like other valves, the valve body is mainly caused by the wear and tear of the valve hole and the loss of hole precision. The repair part of the valve body is generally the valve hole that matches the outer circle of the valve core (geometric accuracy, dimensional accuracy and surface roughness). Valve hole repair If the valve hole is strained or the geometric accuracy is out of tolerance, it can be repaired by grinding or reaming with a grinding rod or an adjustable diamond reamer. When the wear is serious, the inner hole can be brushed or electroplated, and then reamed, or a new valve core can be equipped.

(3) Adjustment lever

When the adjustment rod needs to be replaced, it can be processed according to the original part drawing, and all technical indicators meet the requirements.