一台江淮—50拖拉机在耕地作业中,农具渐渐地不能提升,经检查发现变速箱油位升高。CB3—14齿轮泵上的PD17×30×10油封被冲坏,更换一个新油封,使用几小时后又出现上述情况,如此反复几次,仍然不能解决问题。最后拆开齿轮泵仔细检查发现:齿轮泵前盖上两个偏心环槽的相切处,有个大针鼻大小的孔与通孔“A”相通(见示意图),我们分析这是由于加工上的误差,使两个环槽的切点与通孔“A”之间的壁过薄,又因切点接近高压区,所以在高压油的长期作用下,便将这过薄的壁击穿,形成一个小孔。于是高压油便从齿轮泵的高压区,经φ32×3.1油环 A JAC-50 tractor in arable land operations, tools can not be improved gradually, after inspection found that the transmission oil level rise. CB3-14 gear pump PD17 × 30 × 10 oil seal was washed, replace a new oil seal, use a few hours later appeared above, so repeated several times, still can not solve the problem. Finally, open the gear pump and carefully check the discovery: gear pump front cover two eccentric groove tangential, there is a large needle nose hole size and the through hole “A ” (see diagram), we analyze this Due to processing errors, the two ring groove cut point and through hole “A ” wall is too thin, and because the cut-off point close to the high-pressure zone, so the long-term effect of high pressure oil, it will be too Thin wall breakdown, forming a small hole. So high-pressure oil from the gear pump high-pressure zone, the φ32 × 3.1 oil ring