Loader drive axle planet gear wear reason and improving measures

Loader drive axle planet gear abrasion reasons and improvement measures - 2020 07 - 07 Liu Guosuo ( Xiamen mansion worker bridge box co. , LTD. ) one Fault phenomena appeared in the process of a 5 t wheel loader in use drive axle wheel reducer abnormal fever phenomenon. Apart after inspection, found that the gear transmission system is in good working order, wear volume is not large, but badly worn wheel edge of the planetary gear speed reducer, planetary gear side of gasket has completely into a planetary gear rack. Black gear oil metamorphism, abrasion of planetary gear rack is shown in figure 1. Figure 1 planetary gear rack and pads wear 2. Planetary gear drive axle, the loader adopts the integral frame structure with 2 reduction device. Drive axle center for the bevel gear main reducer, main reducer with the bevel gear differential. Wheel reducer adopts straight tooth planetary gear reducer. The drive axle has the characteristics of compact structure, large reduction ratio, applicable to low speed high torque loader and other construction machinery. In the process of loader work, round edge of the planetary gear speed reducer in planetary gear rack. In order to reduce the friction between them, between the planet gear and planetary gear rack set up before gasket improvement planetary gear structure is shown in figure 2. Figure 2 improvement before the planetary gear planetary gear using 30 crmnti steel frame structure, the overall surface hardness of 56 - after carburizing process 62HRC。 Planetary gear gasket using 45 # steel, quenching hardness of 40 - after processing 45HRC。 Planetary gear rack the QT450 - 10, hardness is 160 - after tempering treatment 210HB。 The three parts of the planet gear rack of low hardness, poor wear resistance. 3. The reason analysis from the force analysis, spur gear by the radial force only, no axial force, gear contrate friction force is small. But in the process of loader work frequently, when they turn differential bevel gears will produce axial force, the axial force by friction acting at the edge of the wheel reducer, which effect on the planet gear. Loader wheel edge when turning gear reducer parts produced by the inertia force, also can produce axial force effect on the planet gear, the axial force between the planet gear, gasket and planetary gear rack produce greater friction. According to wheel reducer structure, analysis and design intent, we will increase the gasket is the purpose of the relative rotation between the planet gear and planetary gear rack, transferred to the relative rotation between the planet gear with gasket, between the planet gear rack and the gasket is not turning, so as to protect the lower hardness of planetary gear rack. But the gasket with the planetary gear rack is fixed, causing friction can occur between the planet gear and the gasket, can also occur between the pads and planetary gear rack. Gasket adopts double smooth structure, there is no storage tank, the oil cannot flow. When the planet gear, gasket, and between planetary gear rack at higher temperatures caused by friction, the friction surface between the oil film temperature, circulating cooling, resulting in a lubricating oil viscosity, oil film rupture, lubrication failure, appear even dry friction, resulting in increased wear and tear. Because of planetary gear rack hardness is low, poor wear resistance, its wear is most serious. Four. Improvement measures in view of the planetary gear wear serious problem, we adopt the following two measures: one is to protect the lower hardness of planetary gear rack, the relative friction occurs in higher hardness, better wear resistance between planetary gear and gasket; The second is to increase the friction surface between the lubrication, cooling, reduce the friction surface temperature, to prevent the oil film are destroyed. Based on the above analysis, we have the gasket structure is improved. The original planet gear gasket thicker, to be broken down into two gaskets, gasket near the planet gear adopts wear-resisting polymer material, in order to increase its wear resistance. Add 3 mm radius on the gasket groove, to speed up the oil flow, reduce the friction surface temperature. Gasket is made of Q235A steel plate stamping near the planet gear rack, set the card slot on the gasket, the planetary gear rack position increase bump card block, with card slot card on the gasket tightly into a dynamic gasket, make the gasket on the planet gear rack, stop it in the process of working with planetary gear does not produce relative rotation, as to reduce the wear and tear of planetary gear rack, increase its service life. As shown in figure 3. Figure 3 improved the structure of planetary gear rack after five. Improvement we will make good gasket and with card slot of planetary gear rack mounted at the edge of the wheel reducer, and unilateral, and a diagonal installed in loader machine test conducted on the front and rear axle of contrast. After 500 h, intensifying test new structure wheel reducer wear occurs only in the planetary gear, high polymer material between gasket, and the wear volume is small, and stop between gasket and planetary gear rack almost no wear and tear. At present, the improved design of the wheel edge reducer has for mass production. Source: engineering machinery and maintenance 2017, 7