What should be paid attention to in the design of the gearbox?


Release time:

2023-02-13

The gearbox is a key component of the gearbox. It assembles the functional components in the reducer (such as shaft teeth, parking, shifting and other related components) into a whole, maintains the correct position between them, and transmits power in accordance with a certain transmission relationship. The shape of the shell should be artistic and aesthetic, and most of the use of curved rods. Under the premise of ensuring the overall stiffness and strength, the aesthetic design of the gearbox is optimized.

The gearbox is a key component of the gearbox. It assembles the functional components in the reducer (such as shaft teeth, parking, shifting and other related components) into a whole, maintains the correct position between them, and transmits power in accordance with a certain transmission relationship. The shape of the shell should be artistic and aesthetic, and most of the use of curved rods. Under the premise of ensuring the overall stiffness and strength, the aesthetic design of the gearbox is optimized.

变速箱体

1. Inspection of assembly clearance

Taking into account the manufacturing error of the transmission case and the internal parts of the transmission, the deformation of the shaft parts, the hydraulic resistance of the lubricating oil flow and other factors, the nominal clearance between the inner wall of the transmission case and the internal static parts of the transmission should usually be 3~4mm, and the nominal clearance between the inner wall of the housing and the internal moving parts of the transmission should be 5~8mm.

2. Lubrication and cooling system layout

The key components of the reducer should be equipped with special lubrication and cooling oil circuit or oil guide structure to avoid lubrication problems caused by poor lubrication. Lubrication is generally divided into splash lubrication and forced spray lubrication of pressure oil. The reducer adopts splash lubrication. When using splash lubrication, it is necessary to determine the oil storage chamber, oil agitator and lubricating oil circuit. The oil reservoir is composed of a closed chamber formed between the transmission housings. Generally, the design of part of the oil passage in the chamber below the transmission installation position is very critical, which should not only prevent casting defects, but also have a good processing technology. Other lubrication mainly depends on the reasonable arrangement of the oil guide plate and oil guide rod inside the housing and the arrangement of the oil groove in the bearing seat.

3. Magnet position design

The magnet should be installed at the lower end of the entire box, and should be reliable and stable. At the same time, it is necessary to reduce orSolve the effect of oil on the magnet, which will cause noise excitation to the housing. At the same time, it is necessary to design the lubrication channel so as not to cause the accumulation of oil, thereby causing the loss of oil stirring.

4. Joint surface design

① Sealing of joint surface-shape

In order to avoid the leakage of the sealant when tightening the bolts, the extruded sealant can easily fall into the transmission and block the lubricating oil circuit, resulting in poor lubrication of the needle roller bearings in the transmission and affecting the service life of the transmission. The design technique is to design the shell connection surface as an inclined type or a rounded corner type.

Aluminum castings are usually slope type, the slope width is 2-3mm, the angle is about 30 °, the flat flange width is greater than 5mm, and the flange width around the bolt hole is greater than 3mm. Or use fillet type, R = 4.5±0.8mm, the ideal gap at the arc is 0.8mm, the direct contact width between flanges is greater than 5mm, and the direct contact part of the flange is in contact.

② Sealing of joint surface-roughness-knife edge

If the roughness value of the joint surface of the housing is too small, it is easy to cause oil leakage of the transmission. Since the joint surface of the housing is too smooth, most of the sealant will be squeezed out. If the sealant cannot be retained on the faying surface, a sealant gasket with a certain thickness cannot be formed. The design technique is that the roughness value of the joint surface of the housing is between 0.8 and 3.2, which is beneficial to the transmission seal.

Cutter lines on the housing mating surfaces also affect the transmission's sealing performance. Knife pattern can be roughly divided into three types: mirror pattern, penetrating pattern and fishing net pattern. The mirror knife pattern means that the joint surface of the shell is as smooth as the mirror surface, and the knife pattern is almost invisible; the penetrating knife pattern means that the knife pattern on the joint surface is in an arc-shaped stripe, extending from the inside of the shell to the outside of the shell; The knife pattern means that the knife patterns on the joint surface of the shell are arc-shaped and intersect, like a fishing net. The design technique is to process the joint surface of the shell into a fishnet knife shape, which is beneficial to the transmission seal.