JP2007298121A - Drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive drum brake having a small number of parts and excellent mountability. <P>SOLUTION: As the drum brake has first engaging parts 38a, 40a provided at center parts of a pair of brake shoes 20, 22 in their longitudinal direction and shoe holding projections 48, 48 standing on a backing plate 16 for slidably pressing and holding the first engaging parts 38a, 40a between a ledge face 16c of the backing plate 16 and them in a manner movable in their diameter directions with the pair of brake shoes 20, 22, the pair of brake shoes 20, 22 can be expandably held without using a mounting type shoe hold down device. Thus, it is possible to manufacture the inexpensive drum brake 10 having a small number of parts and excellent mountability. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drum brake, and more particularly to a technique for holding a brake shoe.

In general, in a drum brake that holds a pair of brake shoes so as to be able to expand, for example, as shown in FIG. The brake shoe is held so as to be movable relative to the backing plate in the surface direction by using a shoe hold-down device.
JP 2004-257538 A

  However, such a conventional shoe hold-down device has a drawback that the drum brake cannot be manufactured at a low cost because it has a large number of parts and is troublesome to assemble.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an inexpensive drum brake having a small number of parts and high assemblability.

  The gist of the invention according to claim 1 to achieve the above object is to provide a drum brake including a backing plate and a pair of arc-shaped brake shoes disposed on the backing plate so as to be expandable. A center portion of the pair of brake shoes in the longitudinal direction is set up on the backing plate and a first engaging portion provided at the center portion to restrict movement in a direction away from the backing plate. And a pair of brake shoes and a shoe holding protrusion that slidably clamps the first engagement portion with the backing plate so as to be movable in the radial direction.

  Further, the gist of the invention according to claim 2 is that the shoe holding projection is bent so as to protrude from the distal end of the base portion to the outer peripheral side by cutting and bending a part of the backing plate. The second engaging portion is provided, and the first engaging portion is clamped between the second engaging portion and the backing plate.

  The gist of the invention according to claim 3 is that the first engagement portion is formed so as to be able to penetrate the shoe rim of the brake shoe so as to receive the second engagement portion, and the shoe rim. It is comprised by the side edge part between these side edges.

  The gist of the invention according to claim 4 is that a side edge portion of the shoe rim constituting the first engagement portion is locally bent toward the inner peripheral side of the backing plate. It is characterized by.

  Further, the gist of the invention according to claim 5 is that the first engaging portion has at least a part of a side edge portion of the shoe rim in a direction parallel to the backing plate, and an inner periphery of the backing plate. It is comprised by the part bent to the side, It is characterized by the above-mentioned.

  According to the drum brake of the first aspect of the present invention, the first engaging portion provided at the central portion of the pair of brake shoes in order to restrict the movement of the central portion in the longitudinal direction away from the backing plate. And a shoe holding projection that is erected on the backing plate and slidably clamps the first engagement portion between the pair of brake shoes and the backing plate so as to be movable in the radial direction. Therefore, the pair of brake shoes is held on the backing plate so as to be able to expand without rattling, and the number of parts for holding the pair of brake shoes is small, and the drum is highly assembled and inexpensive. A brake can be manufactured.

  According to the drum brake of the invention according to claim 2, the shoe holding projection is bent so as to protrude from the distal end of the base portion to the outer peripheral side by cutting and bending a part of the backing plate. A second engagement portion, and the first engagement portion is clamped between the second engagement portion and the backing plate, so that the number of parts of the drum brake can be further reduced and an inexpensive drum brake can be obtained. Can be manufactured.

  According to the drum brake of the invention according to claim 3, the first engagement portion is formed with a through hole formed so as to be able to penetrate the shoe rim of the brake shoe so as to receive the second engagement portion, and a side of the shoe rim. Since it is comprised by the side edge part between edges, an inexpensive drum brake can be manufactured, without almost changing the manufacturing process for manufacturing a pair of brake shoes.

  According to the drum brake of the invention according to claim 4, since the side edge portion of the shoe rim constituting the first engaging portion is locally bent toward the inner peripheral side of the backing plate, it is more reliably performed. The pair of brake shoes can be held on the backing plate so as to be expandable.

  According to the drum brake of the fifth aspect of the present invention, the first engagement portion has a direction in which at least a part of the side edge portion of the shoe rim is parallel to the backing plate and toward the inner peripheral side of the backing plate. Since it is composed of bent portions, an inexpensive drum brake can be manufactured without significantly changing the manufacturing process of the pair of brake shoes.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of a duo-servo type drum-in disc brake 12 having a parking brake drum brake (hereinafter referred to as a drum brake) 10 according to an embodiment of the present invention. It is a front view. The hat type disk 14 includes a disc-shaped outer peripheral portion and a bottomed cylindrical central portion, the disc-shaped outer peripheral portion functions as a friction plate for a disc brake, and the bottomed cylindrical central portion functions as a brake drum. Is configured to do. A circle indicated by a two-dot chain line in FIG. 1 indicates the outer peripheral surface of the bottomed cylindrical central portion.

  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, that is, a non-rotating member such as an axle tube, an axle housing, and a suspension device (not shown). A disc cover 18 for protecting the disc-like outer peripheral portion of the hat type disk 14 is fixed to the outer peripheral portion of the backing plate 16.

  The drum brake 10 includes a pair of arc-shaped brake shoes 20 and 22 disposed substantially symmetrically so as to be able to approach and separate from each other in a posture in which the convex side is outward on the left and right outer peripheral portions of the backing plate 16; A gap adjusting device 26 that is interposed between one end of the pair of brake shoes 20 and 22, that is, the lower end of FIG. 1, and adjusts the shoe gap by changing or extending the entire length as the adjusting wheel 24 rotates. An intermediate portion for constantly urging the lower end portions toward each other to clamp the gap adjusting device 26 in the longitudinal direction is a coiled spring 28 and the other end portions of the pair of brake shoes 20 and 22, that is, FIG. The expansion device 30 provided in a fixed position between the upper end portions of the one, and the expansion device 30 by constantly urging the upper end portions in directions approaching each other. And a coiled return spring 32 for causing the contact.

  An intermediate portion of the spring 28 is brought into contact with the adjustment wheel 24 of the gap adjusting device 26 so that the adjustment wheel 24 does not rotate due to vibration or the like. Since the gap adjusting device 26 and the spring 28 connect one end portions of the pair of brake shoes 20 and 22 so as to be relatively rotatable, they function as a connecting device having a gap adjusting function.

  Each of the brake shoes 20 and 22 has a flat plate shape substantially parallel to the plate surface of the backing plate 16 and the shoe webs 34 and 36 curved in an arc shape in the front view shown in FIG. Strip plate-like shoe rims 38 and 40 integrally fixed so that a cross section forms a substantially T-shape along the outer peripheral side edge forming the shape, and an outer peripheral surface of the shoe rims 38 and 40 with an adhesive or the like The linings 42 and 44 are made of friction materials that are integrally fixed to each other. The backing plate 16, the shoe webs 34 and 36, and the shoe rims 38 and 40 are all pressed parts that are punched from a steel plate and subjected to predetermined bending.

  The shoe rims 38, 40 have protrusions 38 a, 40 a that are locally cut and bent toward the inner peripheral side of the backing plate 16 at both side edges of one end portion, the center portion, and the other end portion in the longitudinal direction; Longitudinal through-holes 46 and 46 that penetrate in the thickness direction of the shoe rims 38 and 40 are provided at positions adjacent to the protrusions 38a and 40a at the center of the 40 in the width direction. Further, the projections 38a, 40a at one end, the center, and the other end of the shoe rims 38, 40 and the through holes 46, 46 are centered on the shoe webs 34, 36 as shown in FIGS. Therefore, the pair of brake shoes 20 and 22 can be used in the opposite direction. That is, the brake shoe 20 can be used as the brake shoe 22 or the brake shoe 22 can be used as the brake shoe 20. The protrusions 38a and 40a at the center of the shoe rims 38 and 40 on the backing plate 16 side correspond to first engaging portions.

  The outer peripheral portion 16a of the backing plate 16 on the side of the pair of brake shoes 20, 22 protrudes toward the pair of brake shoes 20, 22 with reference to the inner peripheral portion 16b of the backing plate 16 as shown in FIGS. And a plurality of portions of the outer peripheral portion 16a have side edges on the backing plate side of the shoe rims 38, 40, that is, one end portion on the backing plate 16 side, a central portion, and a protruding portion on the other end portion. In order to make contact with 38a and 40a, respectively, ledge surfaces 16c and 16c are provided so as to protrude further from the outer peripheral portion 16a and be bent so as to be located in one plane.

  In addition, as shown in FIGS. 2, 3, and 4, the outer peripheral portion 16a of the backing plate 16 is locally cut by pressing a part of the outer peripheral portion 16a inside the central portion in the longitudinal direction of the shoe rims 38 and 40. Bending shoe holding projections 48, 48 are provided. The shoe holding projections 48, 48 are vertically raised base portions 48 c, 48 c, and tips of the base portions 48 c, 48 c are in a direction substantially parallel to the ledge surface 16 c of the backing plate 16, and toward the outer peripheral side of the backing plate 16. It has 2nd engaging part 48a, 48a bent so that it may protrude.

  The shoe holding protrusions 48, 48 are ledge surfaces from the surfaces 48b, 48b on the backing plate 16 side of the second engaging portions 48a, 48a in a state where the second engaging portions 48a, 48a are not inserted into the through holes 46, 46. The distance up to 16c is bent so as to be shorter than the distance between the first engaging portions 38a, 40a in the thickness direction of the shoe webs 34, 36. For this reason, when the second engaging portions 48a, 48a are inserted into the through holes 46, 46 and engaged with the first engaging portions 38a, 40a, an elastic return force is generated and the second engaging portions 48a, 48a are generated. Squeezes the first engaging portions 38a, 40a with the ledge surface 16c of the backing plate 16 so that the first engaging portions 38a, 40a can slide while restricting the movement of the first engaging portions 38a, 40a away from the backing plate 16. The pair of brake shoes 20 and 22 are held so as to be expandable. Further, the first engagement portions 38a and 40a are brought into contact with the ledge surface 16c and the second engagement portions 48a and 48a of the backing plate 16 by the clamping pressure, so that the ledge surface 16c and the second engagement portion 48a are brought into contact with each other. 48a and the first engaging portions 38a and 40a are not rattled and no abnormal noise is generated from the first engaging portions 38a and 40a even if vibration is generated.

  As shown in FIG. 5, the spreading device 30 is a floating type that is movable in the surface direction with respect to the backing plate 16, and has a lever 52 and a strut connected to each other by a connecting pin 50 so as to be relatively rotatable. 54, and the connecting pin 50 is arranged in a posture substantially parallel to the backing plate 16. The lever 52 is composed of two metal plates, and one end connected to the connecting pin 50 is integrally overlapped so as to be in close contact with each other, and is engaged with the brake shoe 22. While the concave portion 56 is provided, the other end portions are separated from each other by a predetermined dimension to be provided with a cable hooking portion 58, and a hooking member 62 fixed to the tip of the parking brake cable 60 is hooked. Yes. The strut 54 is also composed of two metal plates, and the lever 52 is disposed on the inner side thereof, and the other end opposite to the connecting pin 50 is bent inward so as to be in close contact with each other. An engaging recess 64 that is integrally overlapped and engaged with the brake shoe 20 is provided. The lever 52 is provided with a leaf spring 66 bent in a predetermined shape, and guides the parking brake cable 60 to the cable hooking portion 58 of the lever 52 and is once inserted into the cable hooking portion 58. The latch member 62 is prevented from being detached.

  An anchor block 70 is integrally fixed to a vehicle body side member such as an axle housing or a suspension device together with the backing plate 16 by a plurality of bolts 68 on one surface of the backing plate 16 on which the pair of brake shoes 20 and 22 are disposed. The expansion device 30 is supported in contact with the head 68h of the bolt 68, and the anchor block 70 and the backing plate 16 are inserted through the parking brake cable 60. Holes 72 and 74 are provided. A guide pipe 76 that accommodates the parking brake cable 60 on the inner peripheral side is inserted into and inserted into the insertion holes 72 and 74.

  In the expansion device 30 configured as described above, when the operation force from the parking brake lever in the pulling direction is transmitted via the parking brake cable 60, the connecting pin 50 is brought closer to the backing plate 16 side. Thus, the interval between the engaging recesses 56 and 64, that is, the upper ends of the pair of brake shoes 20 and 22 are expanded, and a braking force is generated. On the other hand, when the operating force is returned, the pair of brake shoes 20 and 22 are reduced in diameter according to the urging force of the return spring 32 so that the braking force is released.

  Here, according to the drum brake 10 of the present embodiment, the first central portion provided in the central portion of the pair of brake shoes 20 and 22 to restrict the movement of the central portion in the longitudinal direction away from the backing plate 16. The first engaging portions 38a, 40a are slidable so as to be able to move in the radial direction with respect to the engaging portions 38a, 40a and the pair of brake shoes 20, 22 on the backing plate 16. Since the pair of brake shoes 20 and 22 are held on the backing plate so that the pair of brake shoes 20 and 22 are not rattled, the pair of brake shoes 20 and 22 are held in the backing plate without rattling. Therefore, it is possible to manufacture an inexpensive drum brake 10 having a small number of parts for holding the brake shoe and having high assemblability.

  Further, according to the drum brake 10 of the present embodiment, the pair of brake shoes 20 and 22 can be held so as to be expanded without using a shoe hold-down device. The need to provide a space for disposing in the brake 10 can be eliminated.

  Further, according to the drum brake 10 of the present embodiment, the shoe holding projections 48, 48 are formed on the base portions 48c, 48c raised by cutting and bending a part of the backing plate 16, and from the tips of the base portions 48c, 48c to the outer periphery. Second engaging portions 48a, 48a bent so as to protrude to the side, and the first engaging portions 38a, 40a are provided between the second engaging portions 48a, 48a and the ledge surface 16c of the backing plate 16. Since clamping is performed, the number of parts of the drum brake 10 can be further reduced, and an inexpensive drum brake 10 can be manufactured.

  In the drum brake 10 of the present embodiment, the first engaging portions 38a and 40a are formed so as to be able to penetrate the shoe rims 38 and 40 of the brake shoes 20 and 22 so as to receive the second engaging portions 48a and 48a. The manufacturing process for manufacturing the pair of brake shoes 20 and 22 is almost changed because the through-holes 46 and 46 and the side edges of the shoe rims 38 and 40 are formed. An inexpensive drum brake 10 can be manufactured.

  Further, according to the drum brake 10 of the present embodiment, the side edge portions of the shoe rims 38, 40 are locally bent toward the inner peripheral side of the backing plate 16, so that the pair of brake shoes 20, 22 can be held on the backing plate 16 so as to be expandable.

  Next, another embodiment of the present invention will be described. In the following other embodiments, portions common to the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.

  The drum brake of this embodiment is substantially the same as the drum brake 10 except that it has a shoe holding structure different from that of the above-described embodiment, and FIG. 6 is a diagram illustrating the shoe holding structure of the other embodiments. This corresponds to FIG.

  The brake shoe 80 shown in FIG. 6 has a circular arc shape that is integrally fixed so that the cross section of the shoe web 36 and the outer peripheral side edge forming the circular arc shape thereof is substantially T-shaped. And a shoe rim 82. The shoe rim 82 is bent at both side edges of the central portion in the longitudinal direction of the shoe rim 82 in a direction parallel to the ledge surface 16c of the backing plate 16 and to the inner peripheral side of the backing plate 16. A pair of protrusions 82a. Moreover, since the said protrusion 82a is provided symmetrically on the basis of the shoe web 36, the brake shoe 80 can be used for both right and left. That is, the brake shoe 20 of the above-described embodiment can be used as the brake shoe 80, or the brake shoe 22 of the above-described embodiment can be used as the brake shoe 80. The protrusion 82a on the backing plate 16 side corresponds to the first engagement portion.

  As shown in FIG. 6, the outer peripheral portion 16 a of the backing plate 16 has a shoe erected by locally cutting and bending a part of the outer peripheral portion 16 a inside the central portion in the longitudinal direction of the shoe rim 82. A holding projection 84 is provided. The shoe holding projection 84 includes base portions 84 d and 84 d that rise vertically, and a second engagement portion 84 a that is bent so that the tip ends of the base portions 84 d and 84 d protrude toward the outer peripheral side of the backing plate 16.

  The shoe holding projection 84 is in a state where no external force is applied, that is, in a state where the second engagement portion 84a is not engaged with the surface 82b of the first engagement portion 82a, and the backing plate of the second engagement portion 84a shown in FIG. Since the distance from the tip 84c on the 16th side to the ledge surface 16c is shorter than the distance of the first engagement portion 82a in the shoe web 36 thickness direction, the second engagement portion 84a is engaged with the surface 82b of the first engagement portion 82a. When combined, an elastic biasing force generates a constantly urging force toward the backing plate 16 via the first engaging portion 82a. For this reason, the tip 84c of the second engagement portion 84a squeezes the first engagement portion 82a with the ledge surface 16c of the backing plate 16 so as to be slidable, and holds the brake shoe 80 in an expandable manner. . Due to the clamping pressure, the first engaging portion 82a on the backing plate 16 side comes into contact with the ledge surface 16c of the backing plate 16 and the tip 84c of the second engaging portion 84a, so that the ledge surface 16c, The back end 84c of the second engaging portion 84a and the first engaging portion 82a do not rattle, and no abnormal noise is generated from the first engaging portion 82a even when vibration is applied.

  According to the drum brake of the present embodiment, the first engaging portion 82a is configured so that both side edges of the center portion in the longitudinal direction of the shoe rim 36 are parallel to the ledge surface 16c of the backing plate 16 and the backing plate 16 Therefore, an inexpensive drum brake can be manufactured without changing the manufacturing process of the brake shoe 80 so much.

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

  For example, the drum brake 10 of the above-described embodiment is a drum brake dedicated to a parking brake. However, the present invention can be used for a drum brake as a service brake used while the vehicle is running.

  The drum brake 10 of the above-described embodiment is a duo-servo type drum brake, but there are various modes as long as the drum brake is of a type using a shoe hold down device such as a two-leading type or a leading / trailing type. Is possible.

  Further, in the drum brake 10 of the above-described embodiment, the pair of brake shoes 20 and 22 are expanded by the expansion device 30, but may be expanded by a well-known wheel cylinder.

  The backing plate 16 has the ledge surface 16c on the outer peripheral portion 16a, but may have a shape in which at least two ledge surfaces 16c are connected in the same plane. That is, the backing plate of the drum brake 10 of the present invention is not limited to the shape.

  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.

It is a front view which shows the duo servo type drum brake of one Example of this invention. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is an enlarged view for demonstrating the structure of the expansion apparatus with which the drum brake of the Example of FIG. 1 was equipped. It is a figure which shows the holding structure of the brake shoe of the other Example of this invention, and respond | corresponds to the III-III view sectional drawing of FIG.

Explanation of symbols

10: drum brake 16: backing plates 20, 22, 80: brake shoes 38, 40, 82: shoe rims 38a, 40a, 82a: first engaging portion 46: through hole 48, 84: shoe holding projections 48a, 84a: first 2 engaging portions 48c, 84d: base

Claims (5)

A drum brake comprising a backing plate and a pair of arcuate brake shoes disposed on the backing plate so as to be expandable,
A first engaging portion provided in the central portion for restricting movement in a direction in which a central portion in a longitudinal direction of the pair of brake shoes is separated from the backing plate;
A shoe holding projection that is erected on the backing plate and that slidably clamps the first engagement portion with the pair of brake shoes so as to be movable in a radial direction. A drum brake comprising:   The shoe holding projection includes a base portion that is erected by cutting and bending a part of the backing plate, and a second engagement portion that protrudes from the tip of the base portion toward the outer peripheral side, and the second engagement portion and the backing The drum brake according to claim 1, wherein the first engaging portion is clamped with a plate.   The first engagement portion is constituted by a side edge portion between a through hole formed so as to be able to penetrate the shoe rim of the brake shoe and a side edge of the shoe rim so as to receive the second engagement portion. The drum brake of claim 1 or 2.   The drum brake according to claim 3, wherein a side edge portion of the shoe rim constituting the first engagement portion is locally bent toward an inner peripheral side of the backing plate.   The first engagement portion is configured by a portion in which at least a part of a side edge portion of the shoe rim is bent toward an inner peripheral side of the backing plate in a direction parallel to the backing plate. 1 or 2 drum brakes.

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