Novel automobile brake clearance adjusting arm device

Abstract

The invention discloses a novel automobile brake clearance adjusting arm device. The device comprises an adjusting arm shell, a ratchet wheel, a ratchet block, a forward adjusting rod, a reverse adjusting rod, a return spring, an ejection structure, a forward large gear and a forward small gear, a ratchet wheel hole is formed in the adjusting arm shell, a profiled groove is formed at the top of the inner side of the adjusting arm shell, and the ratchet wheel is rotationally installed in the ratchet wheel hole; the ratchet wheel is in transmission connection with a camshaft; the reverse adjusting rod is rotationally connected into the adjusting arm shell, ejection ratchet teeth are fixed to the reverse adjusting rod, an elliptical hole is formed in the ratchet block, the ejection ratchet teeth are located in the elliptical hole, and a plurality of ratchets are arranged at the bottom of the ratchet block and meshed with ratchets of the ratchet wheel; the profiled groove is formed at the inner side of the adjusting arm shell, the return spring is fixed in the profiled groove, and the bottom end of the return spring abuts against the ratchet block; and the forward adjusting rod rotates in the adjusting arm shell and is connected with the forward small gear, one end of the ratchet wheel is provided with the forward large gear, and the forward small gear is in transmission connection with the forward large gear.

Description

technical field [0001] The invention belongs to the technical field of automobile brakes, and in particular relates to a novel automobile brake clearance adjusting arm device. Background technique [0002] In the existing drum brake systems of large automobiles, buses, and freight heavy trucks, the main function of the adjusting arm is to transmit the braking thrust generated by the brake cylinder to the camshaft, and the camshaft spreads up and down. Two brake shoes, the friction plates on the two brake shoes and the brake drum produce brake friction to ensure timely deceleration and parking. At the same time, the adjustment arm should timely adjust the standard 0.3 between the friction plate and the brake drum -0.6mm braking gap, while the existing adjusting arm technical device is mainly composed of worm gear and worm mechanism, the adjusting arm transmits the braking torque, and is responsible for the functions of braking and returning, which requires the inner part of t...

AI Technical Summary

Problems solved by technology

[0003] However, the service life of the automotive brake adjusting arm in the prior art is short, and the internal worm gear and worm mechanism often fail to self-lock, and the reverse rotation force generated directly damages the main components of the adjusting arm, resulting in a change in the original assembly size of the worm wheel and worm. The amount of freedom of the adjusting arm itself is too large, so that the vehicle does not slow down or stop in time when braking, and cannot fully return to its position after braking. It is formed by the following factors: the adjusting arm is mainly composed of the housing, the worm gear, the worm and the worm shaft. The modulus, the diameter of the indexing circle and the screw pressure angle of the teeth of the worm gear and the worm are the same. During the overlapping assembly process of the two, An oblique assembly gap with a helical pressure angle of 5° is formed. After the assembly is completed, there is only one tooth contact surface. This will cause the reverse thrust of the worm gear to the worm, resulting in the reverse rotation of the adjusting worm shaft. This reverse rotation force and the positive rotation force generated by the adjustment mechanism form a friction intersection point, causing varying degrees of damage to the worm gear and worm teeth in a short period of time, and the service life is short. , the internal clearance of the adjusting arm increases, causing the brake to fail

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