Drum brake apparatus

Patent metadata

Field	Value
Publication number	US-9488234-B2
Application number	US-201314416779-A
Country	US
Kind code	B2
Filing date	Jul 24, 2013
Priority date	Jul 25, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A drum brake apparatus includes first and second brake shoes, a wheel cylinder, an anchor portion, an adjuster, an expansion mechanism for expanding the first and second brake shoes, a switch lever mechanism rotatable by an action force of a given or higher value from the expansion mechanism, and a switch strut, following the rotation of the switch lever mechanism, for expanding the anchor-portion side adjoining ends of the first and second brake shoes.

First claim

The invention claimed is:

1. A drum brake apparatus, comprising:
a pair of brake shoes disposed opposed to an inner peripheral surface of a brake drum and elastically supported movably on a backing plate;
a wheel cylinder interposed between a one-side adjoining ends of the paired brake shoes for expanding the paired brake shoes respectively;
an anchor portion fixed to the backing plate and contactable by another-side adjoining ends of the paired brake shoes;
an adjuster interposed between the one-side adjoining ends of the paired brake shoes existing near the wheel cylinder for adjusting a shoe clearance;
an expansion mechanism arranged in series with the adjuster and, on receiving an operation force, for expanding the paired brake shoes respectively;
a switch lever mechanism rotatably mounted on one of the brake shoes and rotatable by an action force of a given or higher value from the expansion mechanism; and
a switch strut interposed. between the anchor-portion side adjoining ends of the paired brake shoes and, following the rotation of the switch lever mechanism, for expanding the anchor-portion side adjoining ends of the paired brake shoes, wherein
the switch lever mechanism includes a first switch lever rotatably supported on one of the brake shoes by a first fulcrum pin for serving as an input side, and a second switch lever rotatably supported on the one of the brake shoes by a second fulcrum pin for serving as an output side rotatable following the first switch lever; and
the first switch lever receives an action force from the expansion mechanism between a slide contact point of the first swich lever and the second switch lever and the first fulcrum pin.

2. The drum brake apparatus according to claim 1 , wherein
the second switch lever includes a pair of hold portions bent formed for holding a first web of the one of the brake shoes therebetween, and the paired hold portions are rotatably supported on the first web.

3. The drum brake apparatus according to claim 1 , wherein
a side end of the second switch lever contactable with the first switch lever and a side end thereof contactable with the switch strut are bent formed so that they are disposed opposed to each other across the first web of the one of the brake shoes.

4. The drum brake apparatus according claim 1 , wherein
a drive mechanism for pulling a parking cable connected to the expansion mechanism is provided on a back surface of the backing plate.

Assignees

• Akebono Brake Ind

Inventors

• Maehara Toshifumi
• Nakamura Hiroaki

Classifications

• F16D65/562

  arranged between service brake actuator and braking member, and subjected to service brake force · CPC title

• F16D65/14

  Actuating mechanisms for brakes; Means for initiating operation at a predetermined position (brake control systems, parts thereof B60T) · CPC title

• F16D51/28 Primary

  mechanically actuated · CPC title

• F16D51/24

  fluid actuated · CPC title

• F16D51/50

  mechanically actuated · CPC title