Worm and helical gear transmission pair based on variable pressure angle and application of worm and helical gear transmission pair

Abstract

The invention discloses a worm and helical gear transmission pair based on a variable pressure angle and application of the worm and helical gear transmission pair. The worm and helical gear transmission pair is reliable in transmission, durable and easy to manufacture. In order to achieve the purposes, the worm and helical gear transmission pair based on the variable pressure angle comprises a worm and a helical gear which are engaged with each other, wherein the transverse module (Mt2) of the helical gear is equal to the shaft surface module (Ma1) of the worm; the tooth profile angle alpha n2 of the end face reference circle of the helical gear is larger than the tooth profile angle alpha n1 of the shaft surface reference circle of the worm; the swing angle beta 2 of the reference circle of the helical gear is equal to the lead angle lambda 1 of the shaft surface reference circle of the worm; the difference between the tooth profile angle alpha n2 of the end face reference circle of the helical gear and the tooth profile angle alpha n1 of the shaft surface reference circle of the worm is smaller than 10 degrees.

Description

technical field [0001] The invention relates to a worm helical gear transmission pair, in particular to a transmission pair in which a metal worm meshes with a plastic helical gear. Background technique [0002] Worm helical gear transmission has completely replaced worm gear transmission in occasions where the transmission contact surface is small (medium and light load) and transmission accuracy is not strictly required, and it is widely used in automobiles, kitchen appliances and other fields. Automotive motors (wiper wipers, window shakers, etc.) that use worm helical gear transmission require high quality reliability, low noise, long life and low cost, which has become the working direction of the enterprise; [0003] The traditional theory holds that: the correct meshing condition of worm and helical gear transmission is: Mt2 (helical gear end face modulus) = Ma1 (worm shaft face modulus); αt2 (helical gear end face indexing crenated angle) = αa1 (worm shaft β2 (helix...

AI Technical Summary

Problems solved by technology

[0005] 1. Gear injection molds require high precision, are difficult to manufacture, and have a long cycle time;

[0006] 2. Gear injection molding equipment, high precision requirements, strict process;

[0007] 3. The requirements for gear materials are high and the deformation needs to be small. Due to the different thickness of the gears, the tooth shape is easy to deform and the stability is poor.

[0008] We have conducted research on the above-mentioned technical problems for a long time. The method we currently adopt to solve the above-mentioned technical problems is in the metal worm and plastic helical gear transmission. Due to the different material properties and strengths of metal and plastic, we use tangential displacement The method is to reduce the thickness of the tooth profile of the worm, and increase the thickness of the tooth profile of the helical gear correspondingly, so as to achieve the effect that the metal worm gear and the plastic helical gear can bear the same force, avoid the broken teeth of the plastic gear, and meet the life requirements of the motor; At the same time, in order to ensure less noise, the worm usually adopts a small non-standard pressure angle (tooth angle such as 10°, 14.5°, etc.); in order to meet the above requirements, the worm and plastic helical gears are non-standard gears (usually Pressure angle and tooth thickness are non-standard), plastic helical gears need to be processed by injection molding; similarly, the injection mold requires high precision, high cost, long processing cycle, large deformation of injection gear tooth profile (tooth profile uneven thickness), which is not conducive to New product development and mass production

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