Brake structure of electric chain saw

Abstract

The invention discloses a brake structure of an electric chain saw, and belongs to the technical field of mechanical braking. The brake structure of the electric chain saw has improved braking performance and prolonged service life. The brake structure of the electric chain saw comprises an output shaft and a torsion spring, wherein the output shaft is provided with a shaft sleeve which is fixedly connected with the output shaft, the torsion spring and the shaft sleeve are transmitted in a tight fit mode, and the shaft sleeve is made of powder metallurgy. The brake structure of the electric chain saw is applicable to the electric chain saw and other tools with the need of braking.

Description

Technical field [0001] The invention relates to a braking structure used for braking an electric chain saw. Background technique [0002] In the brake structure of a general electric chain saw, the tail end of the torsion spring is ground flat so that the end surface of one end of the torsion spring is on the same plane. The end surface of the torsion spring end is attached to the side surface of the output shaft shoulder to form a surface contact. Due to the finishing process, there is an undercut groove of 2~2.5mm at the matching position of the output shaft and the torsion spring. The undercut will reduce the contact area between the inner ring of the torsion spring and the output shaft and affect the braking effect. When braking, the torsion spring locks the output shaft. Because the end face of the torsion spring's tail end is attached to the side of the output shaft shoulder, the instantaneous friction is large, and the tail of the torsion spring will move radially, which i...

AI Technical Summary

Problems solved by technology

[0002] In the brake structure of a general electric chain saw, the tail end of the torsion spring is ground so that the end face of one end of the torsion spring is on the same plane, and the end face of the tail end of the torsion spring fits with the side of the shoulder of the output shaft to form a surface-to-surface contact. Due to the finishing process, there is a 2-2.5mm undercut at the joint between the output shaft and the torsion spring. The undercut will reduce the contact area between the inner ring of the torsion spring and the output shaft and affect the braking effect.

When braking, the torsion spring locks the output shaft. Since the end surface of the torsion spring is in contact with the side of the output shaft shoulder, the instantaneous friction is large, and the tail of the torsion spring will move radially, which will easily cause the tail of the torsion spring to move. Fatigue fracture, and the roughness inside the relief groove is relatively large, if the tail of the torsion spring moves radially inward, it is more likely to cause friction damage to the torsion spring and the output shaft

In addition, after the heat treatment of the finished torsion spring, there will be a layer of oxide film on the surface as a protective layer. If the tail of the torsion spring breaks, this protective layer will be destroyed and the service life of the entire torsion spring will be affected.

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