JP2005344833A - Back plate for vehicular drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the weight of a drum brake and its cost by increasing the strength of an anchor mounting portion at its periphery which receives braking torque, without increasing the plate thickness of a back plate. <P>SOLUTION: A pair of ledge faces 24, 24 are protruded on both sides of the anchor mounting portion at the outer periphery of the back plate. A pair of reinforcing ribs 18, 18 protruded toward the inner periphery of the back plate are formed on both sides of the anchor mounting portion at the inner periphery of the back plate by bossing a plate material for the back plate 2 to the side of an inner portion. The reinforcing ribs 18, 18 are formed in symmetry with respect to a center line L1 of the anchor mounting portion 21 in the radial direction of the back plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drum brake back plate used in a traveling vehicle such as an automobile or a motorcycle, and more particularly, to a structure of a back plate around an anchor mounting portion for fixing an anchor member.

  In a vehicular drum brake, a brake shoe is housed in a back plate so as to be expandable / contractible. The back plate includes an anchor mounting portion for fixing an anchor member that supports an end of the brake shoe, and the brake shoe. A plurality of ledge surfaces for guiding the expansion and contraction of the back plate are formed by protruding the plate material of the back plate toward the inside.

The back plate has been made thin by reducing the thickness thereof, while securing a strength by attaching a reinforcing member around the anchor receiving the braking torque. The reinforcing member is superimposed on the back plate, and is drawn into the required portion by being drawn (see, for example, Patent Document 1) or embedded in the required portion during pressure forging of the back plate. (For example, refer to Patent Document 2).
JP-A 56-120732 Japanese Utility Model Publication No. 5-71474

  However, in the conventional device, a reinforcing member has to be prepared separately, and it takes time and effort to attach the reinforcing member.

  Therefore, the present invention can increase the strength around the anchor mounting portion that receives the braking torque without increasing the thickness of the back plate, and can reduce the weight and cost of the drum brake. It aims to provide a brake backplate.

  In order to achieve the above object, the first invention accommodates a brake shoe in an expandable / contractible manner, and anchors an anchor member for supporting an end of the brake shoe, and guides the expansion / contraction of the brake shoe. And a plurality of ledge surfaces formed by projecting the plate material of the back plate to the inside, and a pair of ledge surfaces on the outer peripheral side of the back plate on both sides of the anchor mounting portion. A pair of reinforcing ribs are formed on the inner peripheral side by protruding the plate material of the back plate toward the inner side, and the reinforcing ribs are formed symmetrically with respect to the center line of the anchor mounting portion in the radial direction of the back plate. It is characterized by that.

  The second invention is characterized in that the ledge surface that protrudes from the same side surface of the anchor mounting portion and the skirt portions of both the protruding portions of the reinforcing rib are connected to each other.

  According to a third aspect of the present invention, the leading end of the ledge surface and the leading end of the reinforcing rib projecting from the same side surface of the anchor attachment portion are on the same back plate radial direction line or on the same back plate radial direction line. It is characterized by being provided at approximate positions, respectively.

  According to a fourth aspect of the present invention, the extending direction of the ledge surface protruding from the same side surface of the anchor mounting portion and the extending direction of the reinforcing rib are in the direction of the braking torque applied to the anchor mounting portion during braking. It is characterized by intersecting at the same angle or an approximate angle.

  In the fifth aspect of the invention, the brake shoe is housed in an expandable / contractible manner, and an anchor attachment portion for fixing an anchor member that supports the end portion of the brake shoe is formed by protruding the plate material of the back plate to the inside side. In the back plate of a drum brake for a vehicle, a pair of outer reinforcing ribs are formed on the outer peripheral side of the back plate on both sides of the anchor mounting portion, a pair of inner reinforcing ribs are provided on the inner peripheral side of the back plate, and the plate material of the back plate protrudes to the inner side The pair of outer reinforcing ribs and the pair of inner reinforcing ribs are formed symmetrically with respect to the center line in the radial direction of the back plate of the anchor mounting portion.

  The sixth invention is characterized in that the outer reinforcing rib protruding from the same side surface of the anchor attaching portion and the skirt portion of both protruding portions of the inner reinforcing rib are connected to each other.

  According to a seventh aspect of the present invention, the extending direction of the outer reinforcing rib and the extending direction of the inner reinforcing rib projecting from the same side surface of the anchor mounting portion are relative to the direction of the braking torque applied to the anchor mounting portion during braking. And intersecting at the same angle or an approximate angle.

  The eighth invention is characterized in that a ledge surface for guiding expansion and contraction of the brake shoe is formed on the front end side of the pair of outer reinforcing ribs.

  According to the first aspect of the present invention, the braking torque can be distributed to the ledge surface that supports the brake shoe and the reinforcing rib around the anchor mounting portion that receives the braking torque. The strength can be ensured and the cost can be reduced.

  According to the second aspect of the present invention, the braking torque can be effectively dispersed and the strength of the back plate is reliably ensured by integrally forming the ledges at the ridges of the ledge surface and the ridges of the reinforcing ribs. can do.

  According to the third and fourth inventions, it is possible to receive the braking torque substantially equally between the ledge surfaces and the reinforcing ribs, to secure the strength of the back plate and to support the brake shoes stably.

  According to the fifth aspect of the present invention, since the braking torque can be dispersed by the outer reinforcing rib and the inner reinforcing rib around the anchor mounting portion that receives the braking torque, the strength of the back plate is ensured without using a reinforcing member. can do.

  According to the sixth aspect of the present invention, it is possible to effectively disperse the braking torque and to ensure the strength of the back plate by integrally forming the bottom portions of the two protruding portions of the reinforcing ribs together. Can do.

  According to the seventh aspect, the outer reinforcing rib and the inner reinforcing rib can receive the braking torque substantially equally, and the strength of the back plate can be secured and the brake shoe can be stably supported.

  According to the eighth aspect of the invention, the outer reinforcing rib can have the function of a ledge surface, and the configuration can be simplified and the cost can be reduced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1 to 5 show a leading / trailing type drum brake according to a first embodiment of the present invention. The drum brake 1 is provided inside a back plate 2 fixed to a vehicle body with a pair of bow-shaped drum brakes. Brake shoes 3 and 3 are accommodated so as to be freely expandable and contractible. Each brake shoe 3 includes a web 3a whose middle portion is held by a back plate 2 by a shoe hold pin 4 and a shoe hold spring 5, an arc-shaped rim 3b attached perpendicularly to the outer surface of the web 3a, The rim 3b includes a lining 3c attached to the outer peripheral surface of the rim 3b. One end of the web 3a is supported by the wheel cylinder 6, the other end is supported by the anchor 7, and the back plate side surface of the rim 3b is supported by a plurality of ledge surfaces 8 formed on the back plate 2. .

  Return springs 9 and 10 are stretched between both end portions of the webs 3a and 3a, and the brake shoes 3 and 3 are always urged in the direction of diameter reduction by the return springs 9 and 10, and further return on the wheel cylinder side. A braking gap automatic adjusting device 11 is disposed at an inner position of the spring 9. A parking lever 12 is pivotally supported by a parking lever pin 13 at one end of the web 3a between the back plate 2 and the web 3a of one brake shoe 3, and the back plate 2 and the web 3a They are arranged in parallel. One end of a wire cable 14 is connected to the tip of the parking lever 12.

  The back plate 2 is formed with an axle insertion hole 15 at the center, and a positioning hole 16 for the wheel cylinder 6 is formed on the upper side of the axle insertion hole 15 in FIG. An anchor mounting portion 17 is formed on the lower side of the axle insertion hole 15 by projecting the plate material of the back plate 2 in parallel to the inner side, and the anchor mounting portion 17 has rivet holes 17a and 17a. Has been. Further, the above-mentioned ledge surface 8 formed by projecting the plate material of the back plate 2 in parallel to the inner side is provided at each of the left and right side portions of the axle insertion hole 15 at positions corresponding to the brake shoes 3 and 3 respectively. Each is arranged in an arc.

  Two of the ledge surfaces 8 are provided on the outer peripheral side of the back plate on both sides of the anchor mounting portion 17. A pair of reinforcing ribs 18 and 18 projecting toward the inner peripheral direction of the back plate are formed on the inner peripheral side of the back surface of the anchor mounting portion 17 so that the plate material of the back plate 2 protrudes toward the inner side. The ledge surface 8 that protrudes from the same side surface of the portion 17 and the reinforcing rib 18 are formed by connecting the skirt portions 17b of both protruding portions. Further, the pair of reinforcing ribs 18 and 18 are formed symmetrically with respect to the center line L1 of the anchor mounting portion 17 in the radial direction of the back plate, and the tip portion of the ledge surface 8 protruding from the same side surface of the anchor mounting portion 17 8a and the tip 18a of the reinforcing rib 18 are provided at positions approximate to the same back plate radial direction line R1, R2.

  In the drum brake 1 described above, the hydraulic pressure generated in the hydraulic master cylinder by the driver's braking operation is supplied to the wheel cylinder 6 to actuate the piston 6a, and both brake shoes 3, 3 support the anchor 7 as a fulcrum. The outer peripheral linings 3c, 3c are brought into sliding contact with the inner peripheral surface of the brake drum to perform a hydraulic braking action. When the parking lever 12 is rotated by pulling the wire cable 14, the brake shoes 3 and 3 are expanded with the anchor 7 as a fulcrum, and the linings 3 c and 3 c are in contact with the inner peripheral surface of the brake drum, A mechanical braking action as a parking brake is performed.

  Around the anchor mounting portion 17 that receives the braking torque during braking, the end portions of the brake shoes 3 and 3 are supported by the ledge surfaces 8 and 8 and the reinforcing ribs 18 and 18 via the anchor 7. It can be widely dispersed, and the strength of the back plate 2 around the anchor mounting portion 17 can be ensured without using a reinforcing member as in the prior art or without increasing the thickness of the back plate. Furthermore, since the ledge surface 8 that protrudes from the same side surface of the anchor attachment portion 17 and the skirt portion 17 b of both the protruding portions of the reinforcing rib 18 are connected to each other, the skirt portion 17 b functions as an attachment portion of the reinforcing rib 18. It is possible to distribute the braking torque over a wider range and avoid stress concentration.

  The reinforcing ribs 18 are formed symmetrically with respect to the center line L1 in the radial direction of the back plate of the anchor mounting portion 17, and the tip end portion 8a of the ledge surface 8 protruding from the same side surface of the anchor mounting portion 17 The tip 18a of the reinforcing rib 18 is provided at a position approximating the same back plate radial direction line R1, R2, respectively. Therefore, the pair of ledge surfaces 8, 8 and the reinforcing rib 18, 18 are substantially omitted. The braking torque can be received evenly, the strength of the back plate 2 can be ensured, and the brake shoes 3 and 3 can be stably supported.

  In the above-described embodiment, the tip portion 8a of the ledge surface 8 protruding from the same side surface of the anchor mounting portion 17 and the tip portion 18a of the reinforcing rib 18 approximate the same back plate radial direction line R1, R2. The tip portions 8a and 18a may be disposed on the same back plate radial direction lines R1 and R2, respectively. Further, the ledge surface 8 and the reinforcing rib 18 are provided with a braking force applied to the anchor mounting portion 17 during braking by the extending direction of the ledge surface 8 protruding from the same side surface of the anchor mounting portion 17 and the extending direction of the reinforcing rib 18. It may be formed so as to intersect at the same angle or an approximate angle with respect to the direction of torque, so that the braking torque is received substantially evenly by the ledge surface 8 and the reinforcing rib 18. it can.

  FIG. 6 shows a second embodiment of the present invention. The back plate 20 of this embodiment is a pair of outer reinforcements projecting toward the outer periphery of the back plate on the outer periphery of the back plate on both sides of the anchor mounting portion 21. A pair of inner reinforcing ribs 23, 23 projecting toward the inner peripheral direction of the back plate on the inner peripheral side of the back plate on both sides of the anchor mounting portion 21, and the ribs 22, 22, make the plate material of the back plate 20 inward. Each is formed to protrude. Further, the protruding portion 22a of the outer reinforcing rib 22 and the protruding portion 23a of the inner reinforcing rib 23 projecting from the same side surface of the anchor mounting portion 21 are integrally connected by connecting the skirt portions of the protruding portions 22a and 23a. It is formed.

  Further, the pair of outer reinforcing ribs 22 and 22 and the pair of inner reinforcing ribs 23 and 23 are formed symmetrically with respect to the center line L1 of the anchor mounting portion 21 in the radial direction of the back plate, and the anchor mounting portion 21 is formed. The extending direction D1 of the outer reinforcing rib 22 protruding from the same side of the inner reinforcing rib 23 and the extending direction D2 of the inner reinforcing rib 23 are at the same angle with respect to the direction T1 of the braking torque applied to the anchor mounting portion 21 during braking. It is set to intersect. Further, ledge surfaces 24 and 24 are formed on the front end sides of the outer reinforcing ribs 22 and 22 so that the plate material of the back plate 20 protrudes in parallel to the inner side and guides the expansion and contraction of the brake shoes 3 and 3.

  Since the braking torque can be dispersed by the outer reinforcing ribs 22 and 22 and the inner reinforcing ribs 23 and 23 around the anchor mounting portion 21 that receives the braking torque, a reinforcing member can be used or a back plate can be used. The strength of the back plate 20 can be ensured without increasing the thickness of the plate 20. Further, since the outer reinforcing ribs 22 and 22 extend to the outer peripheral side of the back plate and the inner reinforcing ribs 23 and 23 extend to the inner peripheral side of the back plate, the braking torque can be dispersed over a wide range. By integrally forming 22 and the inner reinforcing rib 23, the braking torque can be effectively dispersed, and the strength of the back plate 20 can be ensured reliably.

  The outer reinforcing rib 22 and the inner reinforcing rib 23 are formed symmetrically with respect to the center line L1 in the radial direction of the back plate of the anchor mounting portion 21 and are protruded from the same side surface of the anchor mounting portion 21. The extending direction D1 of the rib 22 and the extending direction D2 of the inner reinforcing rib 23 are set so as to intersect at the same angle with respect to the direction T1 of the braking torque applied to the anchor mounting portion 21 during braking. As a result, the outer reinforcing ribs 22 and 22 and the inner reinforcing ribs 23 and 23 can receive the braking torque substantially evenly, ensuring the strength of the back plate 20 and stably supporting the brake shoes 3 and 3. be able to. Further, by forming the ledge surfaces 24, 24 on the outer reinforcing ribs 22, 22, the configuration can be simplified and the cost can be reduced.

  In the above-described embodiment, the extending direction D1 of the outer reinforcing rib 22 and the extending direction D2 of the inner reinforcing rib 23 that protrude from the same side surface of the anchor mounting portion 21 are the braking torque direction T1. Although they are set to intersect at the same angle, they may intersect at an approximate angle. Furthermore, the front end portion of the outer reinforcing rib 22 and the front end portion of the inner reinforcing rib 23 protruding from the same side surface of the anchor mounting portion 21 are approximated on the same back plate radial direction line or on the same back plate radial direction line. Each of the positions may be provided at each position, so that the braking torque can be received substantially equally by the outer reinforcing rib 22 and the inner reinforcing rib 23.

It is a front view of the backplate which shows the 1st form example of this invention. It is II-II sectional drawing of FIG. It is a perspective view similarly. It is a front view of a drum brake. It is VV sectional drawing of FIG. It is a principal part front view of the backplate which shows the 2nd form example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Drum brake, 2 ... Back plate, 3 ... Brake shoe, 3a ... Web, 3b ... Rim, 3c ... Lining, 4 ... Shoe hold pin, 5 ... Shoe hold spring, 6 ... Wheel cylinder, 6a ... Piston, 7 ... Anchor, 8 ... Ledge surface, 8a ... Tip, 9, 10 ... Return spring, 11 ... Automatic braking gap adjusting device, 12 ... Parking brake, 13 ... Parking lever pin, 14 ... Wire cable, 15 ... Axle insertion hole, DESCRIPTION OF SYMBOLS 16 ... Positioning hole, 17 ... Anchor attachment part, 17b ... Bottom part, 18 ... Reinforcement rib, 20 ... Back plate, 21 ... Anchor attachment part, 22 ... Outer reinforcement rib, 23 ... Inner reinforcement rib, 22a, 23a ... Protrusion 24, ledge surface

Claims (8)

The brake shoe is housed in a retractable manner inside, an anchor mounting portion for fixing an anchor member that supports the end portion of the brake shoe, and a plurality of ledge surfaces that guide the expansion and contraction of the brake shoe, In the vehicular drum brake back plate formed to protrude to the inner side, a pair of ledge surfaces on the outer peripheral side of the back plate on both sides of the anchor mounting portion, a pair of reinforcing ribs on the inner peripheral side of the back plate, A back plate of a drum brake for a vehicle, wherein the plate material is formed by projecting to the inner side, and the reinforcing rib is formed symmetrically with respect to a center line in the radial direction of the back plate of the anchor mounting portion. . 2. The back plate of a drum brake for a vehicle according to claim 1, wherein the ledge surface that protrudes from the same side surface of the anchor attachment portion is connected to the skirt portions of both the protruding portions of the reinforcing rib. The leading edge of the ledge surface and the leading edge of the reinforcing rib projecting from the same side surface of the anchor mounting portion are provided on the same back plate radial direction line or at positions approximate to the same back plate radial direction line, respectively. The back plate of the drum brake for vehicles according to claim 1 or 2 characterized by things. The extending direction of the ledge surface protruding from the same side surface of the anchor mounting portion and the extending direction of the reinforcing rib are the same angle or approximate to the direction of the braking torque applied to the anchor mounting portion during braking. The back plate of the drum brake for vehicles according to any one of claims 1 to 3, wherein the back plate intersects at an angle. The back of a vehicle drum brake, in which the brake shoe is housed in an expandable / contractible manner and an anchor mounting portion for fixing an anchor member that supports the end of the brake shoe is formed by protruding the plate material of the back plate to the inside. In the plate, a pair of outer reinforcing ribs are formed on the outer peripheral side of the back plate on both sides of the anchor mounting portion, a pair of inner reinforcing ribs are formed on the inner peripheral side of the back plate, and the plate material of the back plate is formed by projecting to the inner side. The pair of outer reinforcing ribs and the pair of inner reinforcing ribs are formed symmetrically with respect to the center line of the anchor mounting portion in the radial direction of the back plate, respectively. 6. The back plate of a drum brake for a vehicle according to claim 5, wherein the outer reinforcing rib protruding from the same side surface of the anchor mounting portion and the skirt portion of both protruding portions of the inner reinforcing rib are connected to each other. . The extending direction of the outer reinforcing rib and the extending direction of the inner reinforcing rib protruding from the same side surface of the anchor mounting portion are the same angle with respect to the direction of the braking torque applied to the anchor mounting portion during braking. 7. The back plate of the drum brake for a vehicle according to claim 5, wherein the back plate intersects at an approximate angle. 8. The vehicular drum brake according to claim 5, wherein a ledge surface that guides the expansion and contraction of the brake shoe is formed on a front end side of the pair of outer reinforcing ribs. Back plate.

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