JP2010144791A - Drum brake device having shoe clearance automatic adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drum brake device including a shoe clearance automatic adjusting device reduced in cost of the whole device by reducing the number of components. <P>SOLUTION: A first spring 80 is stretched between a brake shoe 11 and a strut body 71 while a second spring 90 is stretched between a brake shoe 12 and a quadrant 72. The brake shoes are biased to approach each other via the strut. Therefore, the first spring 80 and second spring 90 substitute a shoe return spring stretched between shoe webs on an adjacent portion of one of the brake shoes. <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 directly, an anti-rattle spring is installed between the strut body and the other brake shoe. While set, drum brake device which stretched the quadrant spring between the strut body and the quadrant is widely known.

  A drum brake device is widely known in which a shoe engaging portion of a quadrant is a side protrusion provided on one side of a quadrant, and a quadrant engaging portion of a shoe web is a notch formed in the shoe web.

  According to this structure, three springs, a shoe spring, an anti-rattle spring, and a quadrant spring are required, and not only the parts cost but also the man-hour for assembling the spring increases and the cost of the entire apparatus increases. There's a problem.

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

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a drum brake device including a one-shot type shoe clearance automatic adjusting device in one adjacent portion of the brake shoe. Another object of the present invention is to provide a drum brake device in which a shoe spring is not directly stretched between adjacent portions.

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 engagement portion provided on the quadrant is engaged with the quadrant engagement portion provided on the shoe web of one brake shoe with play, and the expansion amount of the brake shoe exceeds a predetermined value In a drum brake device provided with an automatic shoe gap adjusting device that automatically adjusts a brake shoe gap by rotating a quadrant, a first spring is stretched between a strut body and one brake shoe, and the quadrant and the other A second spring is stretched between the two brake shoes, and a pair of springs urge the pair of brake shoes toward each other. It is a Mubureki apparatus.
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 the spring constituting the shoe gap automatic adjusting device also functions as a shoe-retain spring, the number of springs is reduced and the number of assembling steps is reduced, thereby reducing the cost of the entire device. .

  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 numeral 17 indicates a shoe spring that is stretched between the shoe webs 11 a and 12 a at the other end of the brake shoes 11 and 12 adjacent to the anchor 15, and reference numeral 70 indicates that the brake shoes 11 are adjacent to the wheel cylinder 40. , 12 are struts laid horizontally.

  The brake lever 30 for the parking brake is disposed on the shoe web 12a of the other brake shoe 12, and its base end is pivotally supported by a 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).

<B> Shoe Clearance Automatic Adjustment 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 the 2nd spring 90 is added and the shoe gap automatic adjustment apparatus is comprised.

  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 first spring 80 is stretched between the shoe web 11 a and the strut body 71, and the second spring 90 is stretched between the shoe web 12 a and the quadrant pin 73 fixed to the quadrant 72.
With this structure, the brake shoes 11 and 12 are biased toward each other via the strut 70. Therefore, the first spring 80 and the second spring 90 are replaced by a shoe spring that is stretched between the shoe webs 11a and 12a in one adjacent portion of the brake shoes 11 and 12, and usually several pieces are provided between the brake shoes 11 and 12. Among the stretched shoe springs, the shoe spring on the one adjacent side can be eliminated.

<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 second spring 90.

  When the linings 11c and 12c are worn and the amount of expansion of the pair of brake shoes 11 and 12 exceeds the gap δ between the protruding arm portion 72c of the quadrant 72 and the quadrant engaging hole 11d of the shoe web 12, the protrusions A force that acts on the quadrant 72 in the clockwise direction in FIG. 2 is generated by the force acting on the arm 72c. The adjusting teeth 71b of the strut body 71 and the adjusting teeth 72b of the quadrant 72 are engaged with each other by the spring force of the first spring 80 and the second spring 90. However, when the force to rotate the quadrant 72 increases, the adjusting teeth 71b and 72b slip and 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, and the second spring 90 extends to move the brake shoe 12 in the left direction. It has no effect on the automatic adjustment.

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.

Explanation of symbols

10 Back plates 11 and 12 Brake shoes 11a and 12a Shoe webs 11b and 12b Shoe rims 11c and 12c Lining 11d Quadrant engaging hole 14 Shoe hold device 15 Anchor 17 Shoe return spring 30 Brake lever 31 Pin 40 Wheel cylinder 70 Strut 71 Strut body 71a Notch portion 71b (of strut body) adjustment tooth 71c (strut body) right side portion 72 Quadrant 72a (quadrant) fan-shaped arm 72b (quadrant) adjustment tooth 72c (quadrant) projecting arm 73 Quadrant pin 80 First spring 90 Second 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 pivotally supported in a 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 of the brake shoes with play, and when the expansion amount of the brake shoe exceeds a predetermined value, the quadrant In a drum brake device equipped with a shoe gap automatic adjustment device that rotates and automatically adjusts the brake shoe gap,
A first spring is stretched between the strut body and the one brake shoe, and a second spring is stretched between the quadrant and the other brake shoe so that the pair of brake shoes approach each other by both springs. A drum brake device characterized by being energized.   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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