JP2013007458A - Drum brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum brake having a brake lever reducing the amount of metallic material when manufacturing the brake lever while improving the distal end strength of the brake lever to which the distal end of a brake cable is latched.SOLUTION: A projecting part 48g is formed by thinning the thickness of a part of the inner peripheral side of a backing plate 16 at a peripheral part of a longitudinal through-hole 48c by the drawing of press working to project the part of the inner peripheral side in a direction to approach the backing plate 16. There is therefore no need to provide a plate-like metal portion to be formed bent at the distal end 48b of the brake lever 48 to latch a latch member 54 like the prior art. Further, when the projecting part 48g is pulled by the latch member 54 when braking, the thickness D3 of the projecting part 48j in the pulled direction becomes thicker than the thickness E1 of the brake lever 48 to improve the strength of the distal end 48b of the brake lever 48 compared with the prior art.

Description

  The present invention relates to a drum brake, and more particularly to a technique for improving the performance of a brake lever provided in the drum brake.

  In general, as shown in, for example, Patent Document 1 or 2, a drum brake includes (a) a pair of brake shoes disposed on a backing plate so as to be expandable, and (b) one end of the pair of brake shoes. (C) a brake cable for pulling the tip of the brake lever toward the inner peripheral side of the backing plate, and (d) the Some of them are provided with a hooking member having a diameter larger than the diameter of the cross section of the brake cable fixed to the tip of the brake cable. The brake lever is a press part manufactured by punching from a flat metal plate such as a steel plate and subjected to predetermined bending.

  In the drum brake as described above, for example, in the drum brake of Patent Document 1, as shown in FIG. 3, a hook portion in which the tip of the brake lever is bent in a substantially U shape is formed at the tip of the brake lever. The hook member is hooked on the hook member of the brake cable, whereby the tip of the brake cable is connected to the tip of the brake lever. However, the brake lever having the hook portion whose tip is bent in a substantially U shape as described above has a size of the flat metal plate when the brake lever is manufactured, and the tip of the brake lever is Since the brake lever must be made larger by being bent into a substantially U-shape, a relatively large amount of metal material is required for manufacturing the brake lever, resulting in a problem that the material yield is low.

  On the other hand, as shown in FIGS. 1 and 3, the drum brake of Patent Document 2 is larger than the diameter of the cross section of the brake cable penetrating the tip of the brake lever and larger than the diameter of the hooking member. A longitudinal through hole having a small width dimension, a large diameter hole portion having a diameter larger than the diameter of the hooking member provided at one end portion of the longitudinal through hole, and the other end portion of the longitudinal through hole are formed. A side edge portion of the inner end side of the backing plate at the tip end portion of the brake lever and a bent portion that is bent in a substantially L shape, and is larger than the brake cable that is crimped to the tip end of the brake cable. The brake member is inserted into the large-diameter hole portion of the brake lever and the brake cable is moved to the other end portion of the longitudinal through hole along the inner peripheral surface of the longitudinal through hole. Latch member Bull is hooked to the bent portion of the brake lever. According to such a drum brake of Patent Document 2, the substantially L-shaped bent portion on which the retaining member of the brake cable is latched is formed on the hook in which the tip of the brake lever is bent into a substantially U-shape. It is formed with a small amount of metal material as compared with the portion, and the above problem is solved.

JP 2007-278331 A JP 2003-194118 A

  However, in the drum brake of Patent Document 2 as described above, as shown in FIG. 2, a substantially L-shaped bent portion of the brake lever is pulled by the hook member of the brake cable when the drum brake is braked. Since the thickness of the bent portion is substantially the same as the thickness of the brake lever and is relatively low in strength, the bent portion is bent relatively easily by the tensile force caused by the pull, so that the end of the brake cable There is a problem in that the seating surface of the large-diameter retaining member that is caulked easily tilts.

  The present invention has been made against the background of the above circumstances. The purpose of the present invention is to improve the strength of the front end of the brake lever to which the front end of the brake cable is hooked, as compared with the prior art. An object of the present invention is to provide a drum brake having a brake lever that reduces the amount of metal material at the time of manufacture of the brake lever as compared with the prior art.

  The gist of the first invention for achieving the object is as follows: (a) a pair of brake shoes disposed on the backing plate so as to be expandable, and a predetermined portion at one end of the pair of brake shoes; A long, flat plate-like brake lever that is pivotable around the mounting shaft, a brake cable that pulls the tip of the brake lever toward the inner peripheral side of the backing plate, and a fixed portion at the tip of the brake cable A latching member having a diameter larger than the diameter of the cross section of the brake cable, and a longitudinal through hole having a width dimension larger than the diameter of the cross section of the brake cable and penetrating the tip of the brake lever and smaller than the diameter of the latching member And a large-diameter hole portion having a diameter larger than the diameter of the hooking member provided in a part of the longitudinal through hole, and the hooking member of the brake cable is A drum brake that hooks the hook member of the brake cable to the tip of the brake lever by inserting the brake cable into the large-diameter hole of the key lever and moving the brake cable along the inner peripheral surface of the longitudinal through hole. (B) A part of the inner peripheral side of the backing plate in the periphery of the longitudinal through hole is locally recessed in the direction of approaching the backing plate by press working at the tip of the brake lever. By forming the concave groove, a part of the inner peripheral surface of the longitudinal through hole and a part of the inner peripheral side surface of the backing plate at the tip of the brake lever protrude in a direction approaching the backing plate. (C) The hooking member is received on the side surface of the protruding portion on the outer peripheral side of the backing plate. In the seating surface is provided.

  Further, the gist of the second invention is that, in the first invention, the depth of the concave groove in the thickness direction of the brake lever is the thickness distance of the brake lever and the hook member of the brake cable is In the thickness direction of the brake lever in the state of being latched to the tip of the lever, a part of the outer peripheral surface of the latch member that abuts the surface of the brake lever on the backing plate side contacts the bottom surface of the concave groove. The brake cable is set to be combined with the distance to a part of the outer peripheral surface of the brake cable that comes into contact.

  Further, the gist of the third invention is that in the first invention or the second invention, the tip of the brake lever has a part of the side surface on the outer peripheral side of the backing plate at the tip of the brake lever. The inside of the shoe rim of the one brake shoe is arranged such that all or a part of the protruding portion and the longitudinal through hole are located on the inner peripheral side of the backing plate with respect to the inner peripheral edge of the shoe web of the one brake shoe. The protrusion which protrudes in the direction approaching a surrounding surface, and contacts the inner peripheral surface of the shoe rim is provided integrally.

  According to the drum brake of the first invention, a part of the inner peripheral side of the backing plate in the peripheral portion of the longitudinal through hole is locally applied to the tip of the brake lever in a direction approaching the backing plate by pressing. By forming a concave groove, the part of the inner peripheral surface of the longitudinal through hole and the part of the side surface on the inner peripheral side of the backing plate at the tip of the brake lever approach the backing plate. A protruding portion protruding in the direction is provided, and a seating surface for receiving the hooking member is provided on a side surface of the protruding portion on the outer peripheral side of the backing plate. For this reason, the latch member of the brake cable is inserted into the large-diameter hole of the brake lever, and the brake cable is moved to the protrusion along the inner peripheral surface of the longitudinal through hole. When the latching member is received on the seating surface, the latching member of the brake cable is latched on the protrusion provided at the tip of the brake lever. In addition, since the protruding portion is a portion in which the inner peripheral side of the backing plate in the peripheral portion of the longitudinal through hole protrudes in a direction approaching the backing plate by pressing, Since it is not necessary to provide an extra flat metal part to be bent at the tip of the brake lever in order to latch the latch member, the amount of metal material at the time of manufacturing the brake lever is compared with the conventional one. As a result, the material yield is improved. In addition, when the drum brake is braked, if the protrusion is pulled by the hooking member of the brake cable, the thickness of the protrusion in the pulling direction is determined by the inner circumference of the backing plate of the longitudinal through hole. From the part of the inner peripheral surface on the side to the part of the side surface on the inner peripheral side of the backing plate at the tip of the brake lever, the thickness of the brake lever is preferably increased, so that the hook member of the brake cable The strength of the tip of the brake lever that is latched is improved as compared with the prior art. Therefore, the hooking member received on the seating surface of the protruding portion is prevented from tilting with respect to the brake cable, and the durability of the brake cable is enhanced.

  According to the drum brake of the second invention, the depth of the concave groove in the thickness direction of the brake lever is such that the thickness distance of the brake lever and the hooking member that contacts the surface of the brake lever on the backing plate side. And a distance from a part of the outer peripheral surface of the brake cable to the outer peripheral surface of the brake cable that contacts the bottom surface of the concave groove. For this reason, when the latching member of the brake cable is latched by the protruding portion of the brake lever, a part of the outer peripheral surface of the latching member is brought into contact with the surface of the brake lever on the backing plate side. Since the brake cable is in contact with the bottom surface of the concave groove, the movement of the hooking member of the brake cable with respect to the protruding portion of the brake lever is restricted. Thereby, generation | occurrence | production of the said latching member disengagement from the said brake lever by unintended factors, such as a vibration, is suppressed suitably.

  According to the drum brake of the third aspect of the invention, a part of the outer peripheral side surface of the backing plate at the tip of the brake lever is formed at the tip of the brake lever, or all of the protrusion and the longitudinal through hole. A part of the shoe rim protrudes in a direction approaching the inner peripheral surface of the shoe rim of the one brake shoe so that a part thereof is positioned on the inner peripheral side of the backing plate with respect to the inner peripheral edge of the shoe web of the one brake shoe. Protrusions that come into contact with the inner peripheral surface are integrally provided. For this reason, the protrusion provided at the tip of the brake lever allows the operator to move the brake lever at the tip of the brake lever even when the pair of brake shoes and the brake lever are assembled to the backing plate. Since all or part of the projecting portion and the longitudinal through hole can be seen, the latch member of the brake cable can be easily latched on the tip of the brake lever.

It is a front view which shows the drum brake of one Example of this invention. It is a figure explaining the front-end | tip part of the brake lever with which the drum brake of FIG. 1 was equipped. FIG. 3 is a III-III view of FIG. 2. It is a figure explaining the attachment method of the brake cable which latches the latching member of a brake cable on the protrusion part of a brake lever. It is a figure explaining the attachment method of the brake cable which latches the latching member of a brake cable on the protrusion part of a brake lever, and is a VV view of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 shows a leading / trailing type vehicle drum brake (hereinafter referred to as a drum brake) 10 which is a drum brake with a shoe clearance automatic adjustment mechanism having a parking lock function according to an embodiment of the present invention. FIG. 3 is a front view showing the bottom cylindrical brake drum 12 removed. Further, the brake drum 12 is represented by two concentric circles indicated by a one-dot chain line in FIG. 1, and the circle on the center side of the two circles indicates the inner peripheral surface 14 of the brake drum 12.

  The drum brake 10 has a substantially disc shape, and includes a backing plate 16 that is integrally fixed to a vehicle body side member such as an axle tube, an axle housing, and a suspension device (not shown), that is, a non-rotating member. .

  Further, the drum brake 10 includes a pair of arc-shaped brake shoes 18 and 20 disposed substantially symmetrically so as to be close to and away from each other in a posture in which the convex side is on the outer side of the backing plate 16, and the pair of brake shoes 18 and 20. A wheel cylinder 22 provided in a fixed position on the backing plate 16 between one end of the brake shoes 18 and 20, that is, the upper end of FIG. 1, and one end of the pair of brake shoes 18 and 20 are always attached in a direction approaching each other. In order to urge the wheel cylinder 22 into contact with each other, a coiled return spring 24 stretched between one end portions thereof, a pair of brake shoes 18 so as to be inserted through the inside of the coiled return spring 24, and 20 and a pair of brake shoes 18 and 20 that are bridged between one end portions of the brake 20 when not braked. 1 between the inner peripheral surface 14 of the drum 12, that is, the shoe gap automatic adjusting mechanism 26 that automatically adjusts the shoe gap, and the other ends of the pair of brake shoes 18 and 20, that is, the lower ends of FIG. An anchor member 28 fixed to the backing plate 16, and a spring 30 that is stretched between the other end portions of the pair of brake shoes 18 and 20 so that the other end portions always abut against the anchor member 28. Yes.

  Each of the pair of brake shoes 18 and 20 has a flat plate shape substantially parallel to the flat flat plate portion located on the inner peripheral portion of the backing plate 16 and is entirely curved in an arc shape in the front view shown in FIG. The shoe webs 32 and 34 and the shoe webs 32 and 34 are integrally fixed to the shoe webs 32 and 34 so that the cross-sections are substantially T-shaped along the outer peripheral side edges of the shoe webs 32 and 34 forming the arc shape thereof. Band plate-like shoe rims 36 and 38, and linings 40 and 42 made of a friction material integrally fixed to the outer peripheral surfaces of the shoe rims 36 and 38 with an adhesive or the like, respectively, are configured.

  The pair of brake shoes 18 and 20 are pressed against the backing plate 16 by being pressed in a direction approaching the backing plate 16 by shoe hold-down devices 44 and 46 disposed on the shoe web 32 and the shoe web 34, respectively. On the other hand, relative movement in the surface direction is held. Further, the brake shoe 18 is disposed in a state where a longitudinal flat brake lever 48 is overlapped, and one end portion of the brake shoe 18 and a base end portion 48 a of the brake lever 48 are attached by an attachment shaft 50. The mounting shaft 50 is connected so as to be relatively rotatable. The brake lever 48 is a pressed part manufactured by punching from a flat metal plate such as a steel plate and drawing, for example, a local bending process or the like at a predetermined portion.

  As shown in FIGS. 1 to 3, the front end 48b of the brake lever 48 is moved to the direction of the arrow F1 shown in FIG. 1 by operating a parking brake operating device (not shown). A brake cable 52 is provided that is pulled so as to rotate.

  As shown in FIGS. 1 to 3, the brake cable 52 has a diameter larger than the diameter A of the brake cable 50 fixed to the end of the brake cable 52 by caulking at the end of the brake cable 52 on the brake lever 48 side. A retaining member 54 having a diameter and a return spring 56 wound around the brake cable 52 in a coil shape and disposed in a pressurized state are provided. A brake lever 48 is provided by an elastic return force of the return spring 56. The front end 48b is always urged so as to return in the direction opposite to the arrow F1 direction in FIG.

  Before the latching member 54 is fixed to the end of the brake cable 52, the latching member 54 has, for example, a thick cylindrical shape having an insertion hole 54a through which the brake cable 52 is inserted at the center. The end of the brake cable 52 on the brake lever 48 side is inserted into 54 a and the outer peripheral surface of the thick cylindrical shape is pressed in the radial direction, so that the retaining member 54 is crimped to the end of the brake cable 52. Is. As shown in FIG. 3, the hooking member 54 that is caulked to the brake cable 52 has four side surfaces 52 b that are flatly formed on the outer peripheral surface of the caulking member 54 that is caulked in a substantially square shape, and these side surfaces. It is formed in a substantially quadrangular prism shape so as to have a pair of bottom surfaces 52c orthogonal to 52b. Further, as shown in FIG. 3, in the cross section of the latch member 54, in the diameter of the latch member 54 passing through the center C, the maximum portion is the maximum diameter B1, and the minimum portion is the minimum diameter B2. To do.

  As shown in FIG. 1 to FIG. 3, the brake lever 48 has a diameter A of a brake cable 52 that extends through the distal end portion 48 b of the brake lever 48 so as to extend in the longitudinal direction of the distal end portion 48 b at the center in the width direction of the distal end portion 48 b. A longitudinal through hole 48c that is larger and has a width dimension D1 that is smaller than the minimum diameter B2 of the cross section of the latch member 54, and a brake provided at the end of the longitudinal through hole 48c on the base end portion 48a side of the brake lever 48. A circular large-diameter hole portion 48d having a diameter D2 larger than the maximum diameter B1 of the cross-section of the hooking member 54 so that the hooking member 54 of the cable 52 can be inserted, and a longitudinal through hole 48c of the tip portion 48b thereof. Of the pair of longitudinal portions L1 and L2 opposed to each other, the longitudinal portion L2 on the inner peripheral side of the backing plate 16 is subjected to a local press bending process, for example, a drawing process. The groove 48e that is locally recessed in the direction approaching the base plate 6 is formed, so that a part of the longitudinal portion L2 protrudes locally in the direction approaching the backing plate 16 and its brake lever. A projecting portion 48 i is formed integrally with a portion 48 b on the outer peripheral side of the backing plate 16 at the front end portion 48 b that protrudes in a direction approaching the inner peripheral surface 36 a of the shoe rim 36 of the brake shoe 18.

  Further, as shown in FIG. 1, in the state where the protrusion 48 i provided on the tip 48 b of the brake lever 48 is in contact with the inner peripheral surface 36 a of the shoe rim 36 of the brake shoe 18, the tip of the brake lever 48 is provided. The concave groove 48e of the projecting portion 48g, a part of the longitudinal through hole 48c, and the large-diameter hole portion 48d at 48b are positioned closer to the inner peripheral side of the backing plate 16 than the inner peripheral edge of the shoe web 32 of the brake shoe 18. Be placed.

  As shown in FIGS. 2 and 3, the side surface of the protrusion 48 g of the brake lever 48 on the outer peripheral side of the backing plate 16 functions as a seating surface 48 j that receives the hooking member 54 of the brake cable 52. As shown in FIG. 3, the depth E of the groove 48e of the protrusion 48g in the thickness direction of the brake lever 48 is determined by the thickness distance E1 of the brake lever 48, the radius A / 2 of the brake cable 52, and the latching member 54. The total distance is set to half the minimum diameter B2 of the cross section. 2 and 3, in the protrusion 48g of the brake lever 48, the outer peripheral side surface of the backing plate 16, that is, the seating surface 48j of the protrusion 48g, and the end of the return spring 56 on the brake lever 48 side are provided. The distance D3 between the protruding portion 48g and the side surface 48f on the inner peripheral side of the backing plate 16 is set longer than the thickness distance E1 of the brake lever 48.

  4 and 5 are diagrams for explaining a method of assembling the brake cable 52 for hooking the hook member 54 of the brake cable 52 to the protrusion 48g of the brake lever 48. FIG. Hereinafter, a method of assembling the brake cable 52 will be described.

  4 and 5, when the pair of brake shoes 18 and 20, the return spring 24, the spring 30, the brake lever 48, and the like are assembled to the drum brake 10, the tip of the brake lever 48 is assembled. While visually observing the large-diameter hole portion 48d provided in 48b, the retaining member 54 of the brake cable 52 is inserted into the large-diameter hole portion 48d. 4 and FIG. 5 shows a state in which the brake member 52 and the hooking member 54 of the one-dot chain line are inserted into the large-diameter hole portion 48d. It is.

  Next, as shown by the solid lines in FIGS. 4 and 5, the latching member 54 is inserted into the large-diameter hole portion 48d, and the brake cable 52 is inserted into the longitudinal through hole 48c along the inner peripheral surface of the longitudinal through hole 48c. It is moved in the direction approaching the end opposite to the large-diameter hole 48d of 48c, that is, in the direction of arrow F2. 2 and 3, the brake cable 52 is tilted in the direction of arrow F3 so as to come into contact with the bottom surface 48l of the concave groove 48e, so that the hook member 54 is on the side opposite to the front end side of the brake cable 52. The bottom surface 54c of the projecting portion 48g faces the seating surface 48j of the projecting portion 48g, and the bottom surface 54c is brought into contact with the seating surface 48j of the projecting portion 48g by the urging force of the return spring 56.

  As a result, the latch member 54 of the brake cable 52 is received by the seating surface 48j of the projection 48j of the brake lever 48, and the latch member 54 of the brake cable 52 is latched by the projection 48g of the brake lever 48.

  According to the drum brake 10 configured as described above, when an operating force is generated in the brake cable 52 by operating a parking brake operating device (not shown), the distal end portion 48b of the brake lever 48 is moved in the direction of the arrow F1. The brake shoe 20 is pushed by the shoe gap automatic adjusting mechanism 26 and the brake shoe 18 is pushed by the mounting shaft 50 so that the linings 40 and 42 of the pair of brake shoes 18 and 20 become the inner peripheral surface 14 of the brake drum 12. Abut.

  According to the drum brake 10 of the present embodiment, at the tip 48b of the brake lever 48, a part of the inner peripheral side of the backing plate 16 in the peripheral part of the longitudinal through hole 48c is formed by pressing the backing plate 16 by drawing. By forming the concave groove 48e that is locally recessed in the direction approaching the inner peripheral surface, a part of the inner peripheral surface of the longitudinal through hole 48c and the side surface 48f on the inner peripheral side of the backing plate 16 at the distal end portion 48b of the brake lever 48 are formed. Is provided with a projecting portion 48g projecting in a direction approaching the backing plate 16, and a seating surface for receiving the retaining member 54 of the brake cable 52 on the side surface of the projecting portion 48g on the outer peripheral side of the backing plate 16 is provided. 48j is provided. Therefore, the retaining member 54 of the brake cable 52 is inserted into the large-diameter hole portion 48d of the brake lever 48, and the brake cable 52 is moved along the inner peripheral surface of the longitudinal through hole 48c to the protruding portion 48g. When the latching member 54 is received by the seating surface 48j of the projection 48g, the latch member 54 of the brake cable 52 is latched by the projection 48g provided at the tip 48b of the brake lever 48. Further, the protruding portion 48g provided at the tip 48b of the brake lever 48 has a portion of the backing plate 16 on the inner peripheral side of the peripheral portion of the longitudinal through hole 48c by a local press bending process. 16 so that it is projected in a direction approaching 16, an extra flat plate-like metal portion is provided for bending at the tip 48b of the brake lever 48 in order to latch the latching member 54 as in the prior art. Since it becomes unnecessary, the amount of the metal material at the time of manufacturing the brake lever 48 is reduced as compared with the conventional case, and the material yield is improved. Further, when the protrusion 48g of the brake lever 48 is pulled by the hooking member 54 of the brake cable 52 during braking of the drum brake 10, the thickness D3 of the protrusion 48j in the pulling direction is determined by the backing of the longitudinal through hole 48c. Since a part from the inner peripheral surface of the inner peripheral side of the plate 16 to a part of the side surface 48f of the inner peripheral side of the backing plate 16 at the tip 48b of the brake lever 48 is thicker than the thickness E1 of the brake lever 48, The strength of the tip 48b of the brake lever 48 to which the hooking member 54 of the brake cable 52 is hooked is improved as compared with the prior art. Therefore, the axis of the latching member 54 received on the seating surface 48j of the protrusion 48g is prevented from being inclined with respect to the axis of the brake cable 52, and the protrusion 48g is backed when the brake cable 52 is pulled. Stress is not concentrated on a part of the brake cable 52 that contacts the side edge of the inner peripheral side of the plate 16, and the durability of the brake cable 52 is enhanced.

  Further, according to the drum brake 10 of the present embodiment, the depth E of the concave groove 48e in the thickness direction of the brake lever 48 is equal to the thickness distance E1 of the brake lever 48 and the surface 48k of the brake lever 48 on the backing plate 16 side. The distance E2 from the side surface 54b of the latching member 54 to be contacted to the outer peripheral surface of the brake cable 52 to be in contact with the bottom surface 48l of the concave groove 48e is set. For this reason, when the latching member 54 of the brake cable 52 is latched by the protrusion 48g of the brake lever 48, the side surface 54b of the latching member 54 is brought into contact with the surface 48k of the brake lever 48 on the backing plate 16 side. Since the brake cable 52 is brought into contact with the bottom surface 48l of the concave groove 48e, the hooking member 54 of the brake cable 52 is hooked on the tip 48b of the brake lever 48 and the tip of the brake cable 54 of the hooking member 54 is engaged. When the bottom surface 54c on the opposite side is received by the seating surface 48j of the protrusion 48g, the movement of the hooking member 54 of the brake cable 52 relative to the protrusion 48g of the brake lever 48 is restricted. Thereby, the occurrence of detachment of the latch member 54 from the brake lever 48 due to unintended factors such as vibration is suitably suppressed.

  Further, according to the drum brake 10 of the present embodiment, the tip 48b of the brake lever 48 has a part of the side surface 48h on the outer peripheral side of the backing plate 16 at the tip 48b of the brake lever 48. In a direction approaching the inner peripheral surface 36a of the shoe rim 36 of the brake shoe 18 such that a part of the longitudinal through hole 48c is positioned closer to the inner peripheral side of the backing plate 16 than the inner peripheral edge of the shoe web 32 of the brake shoe 18. A protruding portion 48 i that protrudes and abuts against the inner peripheral surface 36 a of the shoe rim 36 is integrally provided. Therefore, even when the pair of brake shoes 18 and 20 and the brake lever 48 are assembled to the backing plate 16 by the protrusion 48i provided at the tip 48b of the brake lever 48, the brake lever 48 Since the groove 48e of the protrusion 48g, a part of the longitudinal through hole 48c, and the large-diameter hole 48d are visible at the tip 48b, the hook member 54 of the brake cable 52 can be easily attached to the protrusion 48g of the brake lever 48. It can be hung on.

  As mentioned above, although the Example of this invention was described based on drawing, this invention is applied also in another aspect.

  For example, in the drum brake 10 described above, the hook member 54 of the brake cable 52 has a substantially quadrangular prism shape as shown in FIGS. 2 and 3, but a cross section of the brake cable 52 such as a triangular prism shape or a pentagonal prism shape. As long as the diameter is larger than that, the shape of the retaining member 54 may be any. Further, in the drum brake 10 described above, the shape of the large-diameter hole portion 48d penetrating the tip end portion 48b of the brake lever 48 is circular, but the shape of the large-diameter hole portion 48d is the large-diameter hole portion. The shape of the large-diameter hole portion 48d may be any shape as long as the latching member 54 can be inserted into the 48d.

  Further, in the drum brake 10 described above, as shown in FIG. 1, in a state where the protrusion 48 i provided at the tip 48 b of the brake lever 48 is in contact with the inner peripheral surface 36 a of the shoe rim 36 of the brake shoe 18. A part of the longitudinal through hole 48c at the tip 48b of the brake lever 48 is disposed so as to be located on the inner peripheral side of the backing plate 16 with respect to the inner peripheral edge of the shoe web 32 of the brake shoe 18. All of the longitudinal through holes 48 c at the tip 48 b of the lever 48 may be disposed so as to be located on the inner peripheral side of the backing plate 16 with respect to the inner peripheral edge of the shoe web 32 of the brake shoe 18.

  Although not illustrated one by one, the present invention can be implemented in variously modified and improved modes based on the knowledge of those skilled in the art.

10: drum brake 16: backing plate 18, 20: pair of brake shoes 48: brake lever 48b: tip 48c: longitudinal through hole 48d: large diameter hole 48e: concave groove 48f: side surface 48g: protrusion 48j: seating surface 48h: bottom surface 48i: protrusion 50: mounting shaft 52: brake cable 54: latch member E: depth of the groove

Claims (3)

A pair of brake shoes disposed on the backing plate so as to be expandable; and a longitudinal plate-like brake lever disposed on one end of the pair of brake shoes so as to be rotatable about a predetermined mounting shaft; A brake cable for pulling the tip of the brake lever toward the inner peripheral side of the backing plate, a hooking member having a diameter larger than the diameter of the cross section of the brake cable fixed to the tip of the brake cable, From a longitudinal through hole having a width dimension larger than the diameter of the cross section of the brake cable penetrating the tip portion and smaller than the diameter of the retaining member, and from the diameter of the retaining member provided in a part of the longitudinal through hole A large-diameter large-diameter hole portion, and the hook member of the brake cable is inserted into the large-diameter hole portion of the brake lever so that the brake cable extends in the longitudinal direction. Inner by moving along the circumferential surface, a drum brake hooking the hooking member of the brake cable to the front end portion of the brake lever,
At the tip of the brake lever, a concave groove is formed in which a part of the inner peripheral side of the backing plate in the peripheral part of the longitudinal through hole is locally recessed in a direction approaching the backing plate by pressing. Thus, a protrusion is provided in which a part of the inner peripheral surface of the longitudinal through hole and a part of the inner peripheral side surface of the backing plate at the tip of the brake lever protrude in a direction approaching the backing plate. ,
The drum brake according to claim 1, wherein a seating surface for receiving the hooking member is provided on a side surface of the protruding portion on the outer peripheral side of the backing plate.   The depth of the concave groove in the thickness direction of the brake lever is the thickness distance of the brake lever and the thickness direction of the brake lever in a state where the hook member of the brake cable is hooked on the tip of the brake lever. The distance from a part of the outer peripheral surface of the hooking member that contacts the surface of the brake lever on the backing plate side to a part of the outer peripheral surface of the brake cable that contacts the bottom surface of the groove is matched. The drum brake according to claim 1, wherein the drum brake is set to one.   At the tip of the brake lever, a part of the outer peripheral side surface of the backing plate at the tip of the brake lever is part of the protrusion and the longitudinal through hole. A protrusion that protrudes in a direction approaching the inner peripheral surface of the shoe rim of the one brake shoe and is in contact with the inner peripheral surface of the shoe rim so as to be positioned closer to the inner peripheral side of the backing plate than the inner peripheral edge of the web. The drum brake according to claim 1 or 2, wherein the drum brake is provided.

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