1. The cause of oil seal leakage

 

(1) The oil seal is improperly installed. When the oil seal is installed, it is biased and deformed; Oil seal reverse; When the oil seal is installed on the shaft through the shaft head thread spline, scratch the lip or spring off; Shorten the length of the spiral self-tightening spring, which will lead to oil seal leakage or early leakage.

 

(2) The axis itself has defects. The crankshaft, rear axle shaft and other axle parts have bending fatigue deformation after long-term use, and the radial runout and end face runout tolerance exceeds the prescribed standard (the radial runout tolerance of rear axle axle is not greater than 0.04 mm. The runout tolerance of the end face of the rear axle shaft and the radial runout tolerance of the journal surface where the large conical gear is installed is not greater than 0.05mm, and the straightness tolerance is not greater than 0.1mm). When the tractor is running, the shaft will run out in radial direction and end face, and the "following" performance of the oil seal cutting edge to the journal surface will be reduced, resulting in leakage.

 

(3) At the contact between the journal surface and the oil seal cutting edge, the surface is worn with annular groove marks, corrugations and oxide skins, so that there is even a gap between the two. In addition, there is no grinding or replacement of shaft parts during overhaul, so in the test run stage, the oil seal cutting edge will fail early due to rapid wear and rupture. According to the data and use show that: the rotary shaft seal is destroyed, more than 50% is in the shaft neck and oil seal lip contact place, surface wear caused by leakage.

 

(4) Improper installation of oil retaining disc (after the axle shaft oil retaining disc for example). (1) the oil retaining pan is inverted. In replacement of rear axle shaft gear oil pan, the oil baffle plate of open end toward the small taper roller bearing inner ring, thus blocking the gear oil oil flows into the annular cavity (oil seal in tapered roller bearing inner hole after it and rear axle shaft neck and tapered roller bearings to form a 13 mm width of annular oil cavity) or too little oil ring gear oil cavity, The dry friction between the rear axle shaft neck and the oil seal lip will burn out the oil seal edge. Therefore, when installing the oil retaining disc on the shaft, be sure to make the open end towards the open end of the oil seal (with a spring end). ② The oil retaining pan is loose or not installed in the position. After the oil seal is installed into the inner hole of the tapered roller bearing seat, the end face of the open end of the oil seal and the inner end face of the tapered roller bearing seat should be flush. After the oil retaining disc is installed on the journal of the rear axle shaft, there is a 2-2.4mm gap between the end face of the open end of the oil retaining disc and the end face of the open end of the oil sealing. But as a result of oil baffle plate and rear axle shaft axis neck loose with the axial sliding (or) or not to position, make the oil baffle plate of the open end face seal blocking open end face, make the gear oil is difficult to enter the rear axle shaft journal and oil seal lip contact, cause the rear axle shaft dry contact between shaft and oil seal lip, causing overheated oil seal lip, hardening or burn out. Therefore, the interference of 0.147 ~ 0.377 mm must be guaranteed when the oil baffle is installed on the rear axle shaft.

 

(5) Not according to the tractor technical maintenance procedures to do. (1) Too much or too little gear oil filling will cause oil seal leakage. The gear oil of the central transmission and transmission is connected and shared. The oil level can be unscrewed from the oil filling port plug (together with the oil ruler) for inspection. The oil level should reach the oil ruler line, which is added when insufficient, and can be discharged from the small inspection plug on the left side of the oil filling port when excessive. (2) Regular replacement of lubricating oil, regular replacement of gearbox and central transmission gear indoor gear oil. Some operators consider it a waste to completely change the lubricating oil, adding new oil and rarely changing the gear oil in the central transmission and gearbox. In this way, the more impurity content in lubricating oil accumulates, it will cause abrasive wear of shaft, bearing parts and oil seal, and accelerate the early failure of oil seal. Also according to the season to replace the gear oil, otherwise summer with winter gear oil or winter with summer gear oil, will cause the leakage of oil seal.

 

(6) gear oil is not clean. (1) Some transmission boxes and rear axle housing of agricultural machinery are cast parts. The internal sand, sticky sand, residue or metal debris will still be left after sand cleaning. It is difficult to clean up these impurities when repairing. ② tractor in overhaul, gear, shaft, bearing and other parts are not cleaned, will cause the gear oil is not clean. ③ Improper storage, transportation, storage and use of lubricating oil will also lead to impurity invasion.

 

(7) The quality of oil seal is poor. Poor manufacturing quality of oil seal, or improper transportation, storage and storage, so that the oil seal lip aging, surface luster, poor elasticity; Oil seal deformation or lip cracking; The coil spring elasticity is not enough or the spring rust is damaged, etc., will promote the early failure of the oil seal. Therefore, the appearance quality and specifications of the oil seal should be checked in detail during installation. The oil seal is a wearing part, which needs to be replaced regularly. It is suggested to be replaced during the overhaul of the tractor, and it is forbidden to use the used oil seal.

 

 

 

2 Preventive Measures

 

Oil seal leakage is a common fault, and prevention work should be done. (1) For abnormal heating parts, faults should be removed in time to avoid overspeed and overload operation, and to prevent rubber aging and rapid wear due to the temperature rise of oil seal lip. (2) to often check the oil level and quality of lubricating oil, if the oil level is too low or the impurities are too much, to thoroughly replace the new oil, the oil brand and quality to meet the requirements of the season. (3) in the run-in period after the tractor overhaul and the initial period of factory use, it is necessary to check whether the oil seal has leakage oil. Such as the rear axle shaft oil seal, to unscrew the left and right screw plug on the back wall of the rear axle box "inside butter", with the help of light, working lamp or flashlight carefully observe, check whether there is gear oil leakage from the oil seal lip along the conical roller bearing seat to the outside. Attention should be paid to the normal work, do not make the central transmission size bevel gear indoor and final transmission device housing in the gear oil leakage to the steering clutch and brake indoor. In order to check whether this phenomenon occurs, it is necessary to unscrew the oil discharge screw plug under the rear axle spacer (between the partition board and the steering clutch room) and tighten any bolt of the brake belt limiter to release the oil deposit