Uses: Used in automobile gearboxes, it is a typical box and shell parts, similar to most box and shell parts; in order to reduce part wear and power loss caused by internal friction, lubricating oil must be injected into the shell. Splash lubrication lubricates the working surfaces of gear pairs, shafts and bearings. Therefore, there is an oil filler on one side of the shell and an oil drain plug at the bottom, and the oil level is controlled by the position of the oil filler. Radial oil holes are drilled on the first shaft constant meshing gear and the third-speed gear on the second shaft, and the hub end faces of the reverse intermediate gear and the intermediate shaft constant meshing transmission gear are provided with radial oil grooves to lubricate the parts. Needle bearing. In order to prevent lubricating oil from flowing into the clutch from the gap between the first shaft and the bearing cover and affecting its friction performance, an oil seal assembly is installed in the bearing cover, and there is an oil return groove in the inner hole of the bearing cover to prevent oil leakage. To prevent the lubricating oil from flowing out from the rear end of the second shaft. An oil seal assembly is installed in the transmission rear bearing cover. Install sealing gaskets at the joint surfaces of each bearing cover, rear cover, upper cover, front and rear housings, etc., and apply sealant to prevent oil leakage. In order to prevent lubricating oil leakage caused by the increase of oil temperature and pressure when the transmission is working, a vent plug is installed on the transmission mechanism seat and the rear bearing cover of the transmission. Features: It belongs to a typical box and shell part. The main shape and inner cavity shape are cast. The main machine is equipped with mounting surfaces and multiple mounting holes on the same or different surfaces (hole types include through holes, blind holes, screw holes, step holes, etc.). Process requirements: blanks are generally cast from cast iron or cast aluminum. The main processes include: casting-aging treatment-milling-drilling and tapping processing, etc; the main processing equipment has a machining center (three axis, four axis, five axis, etc.). Key inspection items: surface roughness, flatness, hole position, hole cylindricity and other items, key inspection equipment: large and medium-sized precision coordinate measuring machine;