JP2011196515A - Brake panel structure of drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely reduce its weight, while maintaining expected rigidity of a brake panel, by intensively reinforcing the most load-applying part of the brake panel for supporting a drum brake mechanism, in a drum brake.SOLUTION: In the brake panel 7, a support shaft receiving part 20 for supporting a pair of brake shoes 24, a camshaft receiving part 21 for supporting a brake cam for operating the brake shoes 24 and first and second ribs 50 and 51 for respectively integrally connecting mutually-opposed two points P1 and P2 and two points P3 and P4 of the outer peripheral edge of the brake panel 7, are arranged on an inner surface of the brake panel 7.

Description

  The present invention relates to a brake panel structure for supporting a drum brake mechanism of a drum brake for a vehicle, mainly a motorcycle.

  2. Description of the Related Art Conventionally, a drum brake for a motorcycle or the like includes a brake drum that is formed on a wheel hub and accommodates a drum brake mechanism, and a brake panel that is provided so as not to rotate with respect to the brake drum and covers the opening. The brake brake lining is configured to release and operate the brake by bringing the lining of the pair of brake shoes of the drum brake mechanism supported by the brake panel into contact with and separating from the brake plate on the inner peripheral surface of the brake drum. Such a drum brake is already known in which a rib is provided on the inner surface of the panel portion of the brake panel (see Patent Document 1 below).

Japanese Patent No. 3640659

  By the way, since a braking force acts on the brake panel of the drum brake, it is necessary to ensure high rigidity. In the above-mentioned Patent Document 1, the rib contributes to the reinforcement of the brake panel. On the other hand, in response to recent environmental problems, it is desired to reduce the weight of each component while maintaining or improving the performance of each component, and the same applies to the brake panel.

  The present invention has been made in view of such a situation, and intensively reinforces a portion of the brake panel where a high load is applied so as to reduce the weight while maintaining its desired rigidity. An object of the present invention is to provide a brake panel structure for a new drum brake that can be realized.

In order to achieve the above object, the first feature is that a drum brake mechanism is accommodated in a brake drum formed on a wheel hub, and an opening of the brake drum is covered with a non-rotatable brake panel. The panel includes a support bearing portion that supports a support shaft that supports a pair of brake shoes of the drum brake mechanism so that the brake shoes can be expanded and contracted, and a cam bearing portion that supports a cam shaft provided with a brake cam that expands and contracts the brake shoes. In the brake panel structure of the drum brake provided,
The inner surface of the brake panel extends in the radial direction of the support bearing portion, the support bearing portion, a first rib that integrally couples two opposing points on the outer peripheral edge of the brake panel, and the cam bearing The cam bearing portion is extended in the radial direction of the portion, and a second rib that integrally couples two opposing points on the outer peripheral edge of the brake panel is integrally provided.

  In order to achieve the above object, according to a second feature of the present invention, the first feature of the present invention is that the inner surface of the brake panel is connected to one end of the first rib and one end of the second rib. 3, and the convex portion that connects the bearing cylinder portion of the brake panel and the outer peripheral edge thereof in the radial direction is integrally formed between the other end portion of the first rib and the other end portion of the second rib. It is characterized by being provided.

  To achieve the above object, according to a third feature of the present invention, the inner surface of the brake panel extends in a diametrical direction through the center of the inner surface of the brake panel. A fourth rib integrally connecting the second rib and the other end of the second rib; and the other end of the first rib and one end of the second rib extending in the diameter direction through the center. A fifth rib that is integrally connected is provided integrally.

  According to the invention described in each claim, the support bearing portion and the cam bearing portion of the brake panel, which directly receive the braking force when the brake is operated, are reinforced intensively by the first rib and the second rib. , The rigidity of those bearing parts can be greatly increased, and even if the other parts of the brake panel are made thin, the rigidity required for the brake panel can be maintained, and the weight of the brake panel can be reduced. As a result, it is possible to improve the performance of the drum brake, reduce the weight of the drum brake itself, and reduce the cost.

  In particular, according to the second feature, the third rib connecting the one end of the first rib and the one end of the second rib, the other end of the first rib, and the second rib Between the other end portion of the brake panel, and a convex portion connecting the outer peripheral edge of the bearing tube portion of the brake panel in the radial direction to further increase the rigidity of the support bearing portion and the cam bearing portion, and Weight reduction can be achieved.

  Further, in particular, according to the third feature, the fourth rib that integrally connects one end of the first rib and the other end of the second rib, the other end of the first rib, and the first rib With the fifth rib integrally connecting one end portion of the two ribs, the rigidity of the support bearing portion and the cam bearing portion can be further increased, and the weight of the brake panel can be further reduced.

Side view of a front wheel portion of a motorcycle having a brake panel structure of the drum brake of the present invention Enlarged cross-sectional view along line 2-2 in FIG. Enlarged cross-sectional view along line 3-3 in FIG. Sectional view along line 4-4 in FIG. Inner view of brake panel without drum brake mechanism Internal perspective view of brake panel

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention shown in the accompanying drawings.

  In this embodiment, a drum brake having a brake panel structure according to the present invention is implemented on the front wheels of a motorcycle.

  In FIG. 1, a front wheel W is rotatably supported on an axle 2a (see FIG. 2) via an axle 2 on a fork 1F of a front fork 1 that is supported to be steerable by a body frame of a motorcycle. The front wheel W is provided with a diameter-expanding drum brake for braking the front wheel W, and the drum brake includes a brake panel structure according to the present invention.

  As shown in FIGS. 1 to 4, the drum brake includes a brake drum 5 provided integrally with the wheel hub 4 of the front wheel W, a drum brake mechanism 6 accommodated in the brake drum 5, and an opening of the brake drum 5. The brake panel 7 covers the 5M, and the brake panel 7 is slidably engaged with the engaging portion 9 of the front fork 1 in the radial groove 8 formed on the outer surface thereof. The brake drum 5 cannot be rotated (see FIG. 3).

  The axle 2 supported by the front fork 1 passes through a bearing tube portion 10 formed integrally with the center portion of the wheel hub 4 via the bearing 3, and the front wheel W can freely rotate between the fork portions 1F. I support it.

  The brake drum 5 is formed into a hollow cylindrical shape with one end face in the axial direction opened 5M, and the drum brake mechanism 6 is accommodated in the hollow recess 5C. A brake plate 11 is attached to the inner peripheral surface of the brake drum 5.

  On the other hand, the brake panel 7 is formed in a disc shape, and a shaft hole 15 is opened at the center thereof, and the axle 2 is passed through a sleeve 16 fitted in the shaft hole 15. The opening 5M of the brake drum 5 is covered with the brake panel 7, and the outer peripheral surface of the brake panel 7 is loosely engaged with the inner peripheral surface of the opening 5M of the brake drum 5 via a labyrinth packing 17 so as to be relatively rotatable. Yes.

  On the inner surface of the brake panel 7, an enlarged-diameter drum brake mechanism 6 accommodated in the hollow recess 5 </ b> C of the brake drum 5 is supported. On the panel portion 7P of the brake panel 7, a boss-shaped support bearing portion 20 and a cam bearing portion 21 are integrally formed on both outer ends on a diameter line L1-L1 (see FIG. 5) passing through the central axis. Is provided. The support bearing portion 20 is integrally connected to the inner surface of the outer peripheral edge of the brake panel 7, and the support shaft 23 supported on the support bearing portion 20 on the support axis 23 a has a pair of arc shapes. The base ends of the brake shoes 24, 24 are rotatably supported. Brake linings 25 and 25 that can come into contact with and separate from the brake plate 11 are bonded to the arc-shaped outer surfaces of the pair of brake shoes 24 and 24, respectively. Brake return springs 26 and 27 made of tension coil springs are respectively stretched between the base portions of the pair of brake shoes 24 and 24 and between the front portions thereof, and these brake return springs 26 and 27 are paired with a pair of brake shoes. The shoes 24, 24 are biased in the direction of diameter reduction, that is, in the direction away from the brake plate 11. The cam bearing portion 21 is integrally connected to the inner surface of the outer peripheral edge of the brake panel 7, and a cam shaft 29 is rotatably supported on the cam shaft portion 29a by the cam bearing portion 21. An oil seal 45 is interposed between the shaft 29 and the cam bearing portion 21. An oval brake cam 30 is integrally provided at the inner end of the cam shaft 29 protruding into the hollow recess 5C. The free ends of the pair of brake shoes 24, 24 provided with the cam receivers 31, 31 are opposed to both sides of the cam surface of the brake cam 30, and the free ends of the pair of brake shoes 24, 24 are The brake cam 30 is pressed against the cam surface by the resilient force of the brake return springs 26 and 27. Further, the outer end of the cam shaft 29 protrudes outward from the outer surface of the brake panel 7, and a serration 32 is engraved there (see FIG. 1). The base end of the brake arm 34 is fixed to the outer end thereof by bolts and nuts 36. An arm return spring 35 made of a torsion coil spring is connected between the base of the brake arm 34 and the brake panel 7. The elastic force of the arm return spring 35 causes the brake arm 34 to be in a brake release position (FIG. 4). Position). The brake arm 34 extends outward in the radial direction of the brake panel 7, and two brake wires 38 and 39 are connected to the outer ends of the brake arm 34 for independent braking of the front wheel W and for front and rear wheel interlocking braking. (See FIG. 1). By selectively pulling one of these brake wires 38 and 39, the brake arm 34 is swung to the brake operating position. The cam shaft 29 is rotated by the swinging of the brake arm 34 to the brake operating position, and the brake cam 30 supports the pair of brake shoes 24, 24 against the elastic force of the brake return springs 26, 27. The front wheel W can be braked by rotating in the diameter-enlarging direction around 23 and bringing the brake linings 25, 25 on the outer peripheral surface thereof into frictional contact with the brake plate 11 on the inner peripheral surface of the brake drum 5. .

  Also, when the traction of the brake wire 38 (or 39) is released, the brake arm 34 is swung to the brake operation release position by the elastic force of the arm return spring 35, and the camshaft 29 is rotated to the brake release position. Then, the pair of brake shoes 24, 24 are rotated to the reduced diameter position by the elastic force of the brake return springs 26, 27, and the brake of the front wheel W is released.

  Thus, the brake panel 7 of this embodiment is configured to maintain its high rigidity and perform the brake operation accurately and prevent the occurrence of squeal when the brake is operated, while at the same time achieving a significant weight reduction. ing.

  As shown in FIGS. 5 and 6, the support bearing portion 20 and the cam bearing portion 21 are integrally formed on the inner surface of the panel portion 7 </ b> P of the brake panel 7 at both ends on the diameter line L <b> 1-L <b> 1 passing through the center. And a linear first rib that integrally extends the support bearing portion 20 and the two opposing points P1 and P2 on the outer peripheral edge of the brake panel 7 extending in the radial direction of the support bearing portion 20. 50 and the cam bearing portion 21 extend in the radial direction, and the linear second ribs 51 integrally connecting the cam bearing portion 21 and the two opposing points P3 and P4 on the outer peripheral edge of the brake panel 7 are respectively provided. The first rib 50 and the second rib 51 are integrally formed and extend substantially parallel to each other across another diameter line L2-L2 that is substantially orthogonal to the diameter line L1-L1 passing through the center of the brake panel 7. Yes.

  Further, on the inner surface of the panel portion 7P of the brake panel 7, a third rib 52 that connects one end portion 50A of the first rib 50 and one end portion 51A of the second rib 51, and the first rib 50 are provided. Between the other end portion 50B of the second rib 51 and the other end portion 51B of the second rib 51, a convex portion 55 that connects the bearing cylinder portion 10 of the brake panel 7 and the outer peripheral edge thereof in the radial direction is integrally provided. . The third rib 52 extends substantially parallel to the diameter line L1-L1, and the convex portion 55 extends along the other diameter line L2-L2. On the outer surface side of the convex portion 55, the concave groove 8 (see FIG. 3) is formed.

  Furthermore, on the inner surface of the panel portion 7P of the brake panel 7, one end portion 50A of the first rib 50 and the other end portion 51B of the second rib 51 extend in the diameter direction through the center. A fourth rib 53 that is integrally connected, and a fifth rib 53 that extends in the diametrical direction through the center of the fourth rib 53 and integrally connects the other end 50B of the first rib 50 and one end 51A of the second rib 51. Ribs 54 are provided integrally, and the fourth rib 53 and the fifth rib 54 cross each other through the center of the brake panel 7.

  Furthermore, on the inner surface of the panel portion 7P of the brake panel 7, three auxiliary ribs 56, 57, 58 that connect the outer peripheral portion of the support bearing portion 20 and the outer peripheral portion of the bearing tube portion 10, and a cam bearing The other three auxiliary ribs 59, 60, 61 that connect the outer peripheral portion of the portion 21 and the outer peripheral portion of the bearing tube portion 10 are formed symmetrically with respect to the other diameter line L2-L2.

  Thus, the inner surface of the panel portion 7P of the brake panel 7 extends in the radial direction of the support bearing portion 20 and the cam bearing portion 21, and the support bearing portion 20 and the cam bearing portion 21 and the outer peripheral edge of the brake panel 7 are relative to each other. The first bearing 50 and the second rib 51 that integrally couple the two facing points P1, P2 and P3, P4 are integrally provided, so that the support bearing portion that directly receives the braking force when the brake is operated. 20 and the cam bearing portion 21 can be reinforced intensively by the first rib 50 and the second rib 20 to increase the rigidity of the bearing portions 20 and 21 intensively. As a result, the brake panel Even if the other portions of 7 are thin, the rigidity required for the brake panel 7 can be maintained, and the weight can be reduced.

  Further, on the inner surface of the panel portion 7P of the brake panel 7, a third rib 52 that connects one end portion 50A of the first rib 50 and one end portion 51A of the second rib 51, and the first rib 50 are provided. The convex part 55 which connects the bearing cylinder part 10 of the brake panel 7 and its outer periphery in the radial direction is integrally provided between the other end part 50B of the second rib 51 and the other end part 51B of the second rib 51. Further, the rigidity of the support bearing portion 20 and the cam bearing portion 21 can be further increased, and the brake panel P can be further reduced in weight.

  Furthermore, on the inner surface of the panel portion 7p of the brake panel 7, a fourth rib 53 integrally connecting the one end portion 50A of the first rib 50 and the other end portion 51B of the second rib 51, A support bearing portion is provided by integrally providing a fifth rib 54 that extends in the diametrical direction through the center and integrally connects the other end portion 50B of the first rib 50 and one end portion 51A of the second rib 51. 20 and the cam bearing portion 21 can be further increased in rigidity, and the brake panel can be further reduced in weight.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above-described embodiment, the case where the brake panel structure of the drum brake is applied to the front wheel of a motorcycle has been described. However, this may be applied to a wheel or another wheel equipped with a drum brake. it can.

4 .... Wheel hub 5 .... Brake drum 6 .... Drum brake mechanism 7 .... Brake panel 7P ... Panel section 10 ································································································· Brake shoe 30 Brake cam 50 First rib 50A One end 50B The other end 51 Second rib 51A ... One end 51B ... Other end 52 ... Third rib 53 ... Fourth rib 55 ························································································································· 2 opposite points on the outer periphery of 7

Claims (3)

A drum brake mechanism (6) is accommodated in a brake drum (5) formed on the wheel hub (4), and an opening (5M) of the brake drum (5) is covered by a brake panel (7) provided so as not to rotate. The brake panel (7) includes a support bearing portion (20) for supporting a support shaft (23) that supports the pair of brake shoes (24, 24) of the drum brake mechanism (6) so as to be able to expand and contract, In the brake panel structure of a drum brake, comprising a cam bearing portion (21) for supporting a cam shaft (29) provided with a brake cam (30) for expanding and contracting the brake shoes (24, 24).
The inner surface of the brake panel (7) extends in the radial direction of the support bearing portion (20), and the support bearing portion (20) and two opposing points (P1, P1) of the outer peripheral edge of the brake panel (7). P2) and the first rib (50) integrally connecting to each other and extending in the radial direction of the cam bearing portion (21). The cam bearing portion (21) and the outer peripheral edge of the brake panel (7) are opposed to each other. A brake panel structure for a drum brake, wherein a second rib (51) that integrally couples the two points (P3, P4) is integrally provided.   A third rib (52) connecting one end (50A) of the first rib (50) and one end (51A) of the second rib (51) to the inner surface of the brake panel (7) Between the other end (50B) of the first rib (50) and the other end (51B) of the second rib (51), the bearing cylinder (10) of the brake panel (7), and The brake panel structure for a drum brake according to claim 1, wherein a convex portion (55) connecting the outer peripheral edge in the radial direction is integrally provided.   One end (50A) of the first rib (50) and the other end (51B) of the second rib (51) extend in the diameter direction through the center of the inner surface of the brake panel (7). A fourth rib (53) integrally connecting the first rib (50) and the other end (50B) of the first rib (50) and one end of the second rib (51). The brake panel structure for a drum brake according to claim 1 or 2, wherein a fifth rib (54) integrally connecting (51A) is integrally provided.

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