JP2010164173A - Drum brake device including automatic shoe clearance adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drum brake device having only one adjuster spring and reducing the number of components to reduce the cost of the whole device, in a one-shot type automatic shoe clearance adjuster provided in one adjacent portion of brake shoes. <P>SOLUTION: In this drum brake device including a shoe return spring 18 biased in a direction where the one adjacent portion of a pair of brake shoes 11, 12 relatively approaches, the adjuster spring 80 is stretched tightly between a quadrant 72 and the other brake shoe 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drum brake device, and more particularly to a drum brake device including a one-shot type shoe gap automatic adjusting device.

  A strut body is disposed between adjacent ones of a pair of opposing brake shoes, a quadrant can be rotated at one end of the strut body, and is movably supported in the longitudinal direction of the strut body. The shoe engaging part (protruding arm) provided at one end is engaged with the quadrant engaging part (quadrant engaging hole) provided in the shoe web of one brake shoe with play, and the brake shoe is expanded. The quadrant rotates when the amount exceeds a predetermined value to automatically adjust the brake shoe gap, and includes a shoe clearance automatic adjustment device between the brake shoes at one adjacent portion of the pair of brake shoes. In a drum brake device with a spring stretched, an anti-rattle spring is stretched between the strut body and the other brake shoe. Both drum brake device which stretched the quadrant spring between the strut body and the quadrant is widely known (Patent Document 1).

  Further, a drum brake device is widely known in which a quadrant shoe engaging portion is a side protrusion provided on one side of the quadrant, and a shoe web quadrant engaging portion is a notch formed in the shoe web (Patent Document 2). ).

  According to this structure, two springs of an anti-rattle spring as the first adjuster spring and a quadrant spring as the second adjuster spring are required, and not only the cost of the parts but also the man-hour for assembling the spring increases. Therefore, there is a problem that the cost of the entire apparatus increases.

Japanese Patent Publication No. 59-126127 European Patent Publication No. 0462731

  The present invention has been made to solve the above-described problems. The object of the present invention is to provide a one-shot type automatic shoe clearance adjusting device adjacent to one of the brake shoes and one of the pair of brake shoes. An object of the present invention is to provide a drum brake device provided with only one adjuster spring in a drum brake device provided with a shoe spring that biases in a direction in which adjacent portions relatively approach each other.

In the present invention, a strut body is disposed between adjacent ones of a pair of opposing brake shoes, a quadrant can be rotated at one end of the strut body, and is movably supported in the longitudinal direction of the strut body. When the shoe engaging portion provided on the quadrant is engaged with the quadrant engaging portion provided on the shoe web of one brake shoe with play, and the expansion amount of the brake shoe exceeds a predetermined value. It is equipped with a shoe clearance automatic adjustment device that automatically adjusts the brake shoe clearance by rotating the quadrant, and a shoe retraction spring that biases one adjacent portion of the pair of brake shoes closer to each other. In this drum brake device, an adjuster spring is stretched between the quadrant and the other brake shoe.
Further, in the above drum brake device, the quadrant shoe engaging portion is a protruding arm portion provided at one end of the quadrant, and the quadrant engaging hole of the shoe web is a quadrant engaging hole formed in the shoe web, This is a drum brake device in which a protruding arm is engaged with a quadrant engagement hole with play.

  According to the present invention, since only one spring is included in the shoe gap automatic adjusting device, the number of springs is reduced, the number of assembling steps is reduced, and the cost of the entire device is reduced.

The top view of the drum brake device provided with the shoe gap automatic adjustment device concerning the present invention II-II sectional view of FIG.

[Example]

  Embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show a drum brake device according to an embodiment of the present invention.

<A> Overall Structure of Drum Brake FIG. 1 shows an example of a leading / trailing type (LT type) drum brake having a parking brake mechanism and a one-shot type shoe clearance automatic adjusting device. Reference numeral 10 denotes a back plate fixed to a non-moving portion of the vehicle with a bolt or the like, and a pair of brake shoes 11 and 12 are slidably supported by known shoe hold devices 14 and 14.

  A pair of brake shoes 11 and 12 having a T-shaped cross section formed by joining shoe rims 11b and 12b to shoe webs 11a and 12a and fixing linings 11c and 12c to outer peripheral surfaces of shoe rims 11b and 12b, respectively. Ends (upper ends in FIG. 1) are respectively engaged with pistons (not shown) of a wheel cylinder 40 that is a shoe expansion device for service brakes, and other ends (lower ends in FIG. 1) are fixed to the back plate 10. Each anchor 15 is supported.

  The wheel cylinder 40 is fixed to the back plate 10 with a bolt or the like, and its piston (not shown) is configured to always move in the expansion / contraction direction of one end of each brake shoe 11, 12.

  Reference numerals 17 and 18 denote shoe springs that are stretched between the shoe webs 11 a and 12 a at the other end of both brake shoes 11 and 12 adjacent to the anchor 15 and at one end of both brake shoes 11 and 12 adjacent to the wheel cylinder 40. Reference numeral 70 denotes a strut that is horizontally mounted between the brake shoes 11 and 12 adjacent to the wheel cylinder 40.

  The brake lever 30 for the parking brake is arranged on the shoe web 12a of the other brake shoe 12, and its base end is pivotally supported by the lever pin 31 at the upper end of the shoe web 12a. ing. A remote force transmission brake cable (not shown) is connected to the free end of the brake lever 30 (the lower end in FIG. 1).

<Ro> Automatic shoe clearance adjusting device As shown in FIG. 2, the strut 70 includes a plate-like strut body 71, a quadrant 72, and a quadrant pin 73 fixed to the quadrant 72, and an adjuster spring 80 is attached to the strut 70. In addition, an automatic shoe clearance adjusting device is configured.

  The strut body 71 disposed adjacent to the wheel cylinder 40 and parallel to the back plate 10 has a notch 71a formed on the left side to accommodate the brake lever 30 and the shoe web 12a, and the notch 71a. The bottom surface of the bracket supports the brake lever 30. Small adjustment teeth 71b are engraved in the middle portion of the strut body 71.

  A quadrant pin 73 is fixed to an intermediate portion of the quadrant 72, and the quadrant 72 is rotatable to the right portion 71 c of the strut body 71 and is movably movable along the longitudinal plate surface of the strut body 71. It is pivotally supported by a runt pin 73, and small adjustment teeth 72b carved on the outer periphery of the fan-shaped arm portion 72a mesh with the adjustment teeth 71b of the strut body 71. Further, the protruding arm portion 72c having a cam surface is loosely fitted on the inner surface of the brake inner side of the quadrant engagement hole 11d formed in the shoe web 11a of the brake shoe 11 with a predetermined gap δ, and the cam The surface is in contact with the brake outer side inner surface of the quadrant engagement hole 11d.

The adjuster spring 80 is stretched between the shoe web 12 a and the quadrant pin 73 fixed to the quadrant 72.
With this structure, the adjuster spring 80 biases the entire strut 70 to the other brake shoe 12 while elastically biasing the quadrant 72 to the strut body 71. Therefore, conventionally, two adjuster springs can be provided.

<C> Automatic adjustment of shoe clearance When the pair of brake shoes 11 and 12 are expanded by the service brake operation, the strut 70 follows the other brake shoe 12 by the spring force of the adjuster spring 80.

  When the linings 11c and 12c wear and the amount of expansion of the pair of brake shoes 11 and 12 exceeds the gap δ between the projecting arm portion 72c of the quadrant 72 and the quadrant engaging hole 11d of the shoe web 12a, the projection Due to the force acting on the arm portion 72c, a force is generated for the quadrant 72 to rotate clockwise in FIG. The adjustment teeth 71b of the strut body 71 and the adjustment teeth 72b of the quadrant 72 are engaged with each other by the spring force of the adjuster spring 80. The meshing state changes by one tooth. At this time, the contact point of the cam surface of the protruding arm portion 72c that contacts the quadrant engaging hole 11d of the shoe web 11a is displaced by an amount corresponding to one tooth, and the quadrant engaging hole 11d supported by the protruding arm portion 72c is displaced. The distance L between the inner surface of the brake outer side and the groove bottom of the strut body 71 that supports the inner edge of the brake lever 30 is extended to keep the shoe gap substantially constant. In other words, the substantial effective length of the strut 70 is extended to close the gap between the brake shoes 11 and 12 and the brake drum (not shown), and the shoe gap is always kept substantially constant.

  Further, when the parking brake is operated, the strut 70 moves together with the brake shoe 11 in the right direction in the figure, the adjuster spring 80 extends, and the brake shoe 12 only moves in the left direction. It has no effect on the adjustment.

10 Back plates 11, 12 Brake shoes 11a, 12a Shoe webs 11b, 12b Shoe rims 11c, 12c Lining 11d Quadrant engaging holes 14 Shoe hold device 15 Anchors 17, 18 Shoe return spring 30 Brake lever 31 Lever pin 40 Wheel cylinder 70 Strut 71 Strut Body 71a (Strut body) cutout 71b (Strut body) adjustment tooth 71c (Strut body) right side 72 Quadrant 72a (Quadrant) fan-shaped arm 72b (Quadrant) adjustment tooth 72c (Quadrant) protrusion Arm 73 Quadrant Pin 80 Adjuster Spring

Claims (2)

A strut body is disposed between adjacent ones of a pair of opposing brake shoes, a quadrant can be rotated at one end of the strut body, and is movably supported in the longitudinal direction of the strut body. The shoe engagement portion provided on the brake shoe is engaged with the quadrant engagement portion provided on the shoe web of one brake shoe with play, and the quadrant is disengaged when the expansion amount of the brake shoe exceeds a predetermined value. A drum having a shoe clearance automatic adjusting device that rotates and automatically adjusts the clearance of the brake shoe, and is provided with a shoe return spring that biases one adjacent portion of the pair of brake shoes in a relatively approaching direction. In the brake system,
An adjuster spring is stretched between the quadrant and the other brake shoe,
Drum brake device.   2. The quadrant according to claim 1, wherein the quadrant shoe engaging portion is a protruding arm portion provided at one end of the quadrant, and the quadrant engaging portion of the shoe web is formed in the shoe web. A drum brake device characterized in that an engagement hole is provided, and the protruding arm portion is engaged with the quadrant engagement hole with play.

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