JP2010174932A - Drum brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drum brake for vehicle, in which the plate thickness of one end part of a shoe web is increased so as to resist input of high load in braking, while reducing the manufacturing cost of the shoe web. <P>SOLUTION: The shoe web 36 is configured so that one end part thereof is allowed to abut on an anchor member 72 in braking, whereby a brake she 22 is received by the anchor member 72. The one end part of the shoe web 36 is subjected to installation treatment with its top end being bent in the thickness direction of the shoe web 36, thereby being increased in thickness oppositely to the bending direction. Thus, the one end part of the shoe web 36 is bent first, whereby the increase amount of increasing the plate thickness of the one end part of the shoe web 36 by the following installation treatment is reduced, compared with a conventional one in which the plate thickness of the one end part of the shoe web is increased by pressing so as to resist the input of high load in breaking. Therefore, the plate thickness of the one end part of the shoe web 36 can be increased without quenching process so that it can resist the input of high load in braking. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicular drum brake, and more particularly to a technique for reducing the manufacturing cost of a vehicular drum brake.

  For example, as shown in Patent Document 1, a vehicle drum brake includes (a) a backing plate, (b) a pair of arcuate brake shoes disposed on the backing plate so as to be expandable, and (c) An anchor member fixed to the backing plate to abut one end of the pair of brake shoes, and (d) a bottomed cylindrical rotating drum that rotates integrally with the wheel, and (e) The pair of brake shoes is expanded and the pair of brake shoes are brought into sliding contact with the inner peripheral surface of the rotating drum, thereby braking the rotation of the wheels. (f) The brake shoe has an arc-shaped and flat shoe web, and (g) the shoe web is brought into contact with the anchor member at the time of braking so that the brake shoe is brought into contact with the anchor member. It is something that can be accepted.

JP 2007-298121 A

  During braking of the vehicle drum brake, a high load force is input from the anchor member to the one end portion of the shoe web, so that the one end portion of the shoe web is, for example, induction hardened so as to withstand the high load. In this state, the thickness was increased by press working to increase the thickness, thereby increasing the strength.

  For this reason, in order to increase the thickness of the one end portion of the shoe web, a quenching process such as induction hardening is required, and there is a problem that the manufacturing cost of the shoe web, that is, the brake shoe is increased. There is also an idea of performing the press work without performing the quenching step, but by doing so, a large press machine with a high load is required, and the manufacturing cost of the shoe web, that is, the brake shoe is increased. There was also.

  The present invention has been made against the background of the above circumstances, and its purpose is to increase the thickness of one end portion of the shoe web so as to withstand the input of a high load during braking. An object of the present invention is to provide a vehicular drum brake that reduces the production cost of a shoe web.

  In order to achieve this object, the gist of the invention according to claim 1 is that (a) a backing plate, and (b) a pair of arcuate brake shoes disposed on the backing plate so as to be expandable. And (c) an anchor member fixed to the backing plate for abutting one end of the pair of brake shoes, and (d) a bottomed cylindrical rotating drum that rotates integrally with the wheel. (E) a vehicular drum brake that brakes the rotation of a wheel by expanding the pair of brake shoes and sliding the pair of brake shoes on the inner peripheral surface of the rotating drum, f) The brake shoe has an arcuate and flat shoe web, and (g) the shoe web is brought into contact with the anchor member at the time of braking so that the brake shoe is fixed to the anchor shoe. -It is to be received by the member. (H) One end of the shoe web is opposite to the bending direction by being upset with the tip bent in the thickness direction of the shoe web. It is characterized in that it is thickened to the side.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, the amount of bending at which the tip is bent in the thickness direction of the shoe web at one end of the shoe web is the shoe web. It is characterized by being equal to or less than the plate thickness.

  According to the vehicle drum brake of the invention according to claim 1, (f) the brake shoe has an arc-shaped and flat plate-shaped shoe web, and (g) the shoe web has its one end portion being braked when the brake is applied. The brake shoe is received by the anchor member by being brought into contact with the anchor member, and (h) one end portion of the shoe web is installed with its tip bent in the thickness direction of the shoe web. Since the thickness of the shoe web is increased in the direction opposite to the bending direction when the processing is performed, one end portion of the shoe web is bent in the thickness direction of the shoe web. The thickness in the thickness direction is increased, and the thickness is increased on the side opposite to the bending direction by performing upsetting with the tip bent in the thickness direction of the shoe web. Thickness is as thick as. That is, by first bending one end portion of the shoe web, the thickness of the shoe web at one end portion is increased only by press working to increase the thickness of the one end portion of the shoe web by subsequent upsetting. Because it is less than the conventional type that increases the thickness to withstand high load input during braking, it can withstand high load input during braking without using a quenching process or a large press machine with high load. Thus, the thickness of the end portion of the shoe web can be increased. Further, since the quenching process or a large press machine with high load is not used in order to increase the thickness of one end of the shoe web, the production cost of the shoe web can be reduced.

  According to the vehicle drum brake of the invention according to claim 2, the bending amount at which the tip is bent in the thickness direction of the shoe web at one end portion of the shoe web is equal to or less than the plate thickness of the shoe web. Therefore, the center position of the load input from the anchor member to the one end of the shoe web during braking can be within the plate thickness of the flat shoe web in the thickness direction of the shoe web.

It is a front view which shows the duo servo type drum brake of one Example of this invention. It is sectional drawing 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 only the brake shoe in the drum brake of this invention. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a figure which shows the manufacturing process until the shoe web shown in FIG. 3 is manufactured from a steel plate. It is a figure explaining the press process shown by FIG. It is a figure explaining the bending process shown by FIG. 7 will be described with reference to FIG. 7 and a thickened part forming apparatus in which the thickness of one end of the long plate member is increased and the thickened part forming step shown in FIG. 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 is a front 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 removed from the hat-type disc and caliper. FIG. The hat type disc has a disc-shaped outer peripheral portion and a bottomed cylindrical central portion, and the disc-shaped outer peripheral portion functions as a friction plate of the disc brake, and the bottomed cylindrical central portion is integrated with the wheel. It is comprised so that it may function as a brake drum (rotating drum) 14 that rotates in a straight line. Further, the brake drum 14 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 16 of the brake drum 14.

  The drum brake 10 has a substantially disc shape, and includes a backing plate 18 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. A disc cover 20 is secured to the outer periphery of the backing plate 18 to protect the disc-like outer periphery of the hat type disc.

  Further, the drum brake 10 includes a pair of arc-shaped brake shoes 22 and 24 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 18, and the pair thereof. 1 and a widening device 26 provided at a fixed position between the upper ends of FIG. 1 and the upper ends of FIG. A coil-shaped return spring 28 for contact with the other end of the pair of brake shoes 22 and 24, that is, the lower end of FIG. Accordingly, the gap adjusting device 32 for adjusting the shoe gap and the lower end portions of the gap adjusting device 32 are always urged toward each other to sandwich the gap adjusting device 32 in the longitudinal direction. An intermediate portion to have a coiled spring 34.

  An intermediate portion of the spring 34 is brought into contact with the adjustment wheel 30 of the gap adjusting device 32 so that the adjustment wheel 30 does not rotate due to vibration or the like. Since the gap adjusting device 32 and the spring 34 connect the other end portions of the pair of brake shoes 22 and 24 so as to be relatively rotatable, they function as a connecting device having a gap adjusting function.

  Each of the pair of brake shoes 22 and 24 has a flat plate shape substantially parallel to the plate surface of the backing plate 18, and shoe webs 36 and 38 that are entirely curved in an arc shape in the front view shown in FIG. Band-plate-like shoe rims 40, 42 integrally fixed so that the cross section forms a substantially T-shape along the outer peripheral side edge forming an arc shape, and an adhesive or the like on the outer peripheral surfaces of the shoe rims 40, 42 And linings 44 and 46 made of a friction material fixed integrally with each other. The pair of brake shoes 22 and 24 are held so as to be movable relative to the backing plate 18 in a plane direction by shoe hold-down devices 48 and 50 disposed on the shoe webs 36 and 38, respectively. The backing plate 18, the shoe webs 36 and 38, and the shoe rims 40 and 42 are all pressed parts that are punched from a steel plate and subjected to predetermined bending.

  As shown in FIG. 2, the spreading device 26 is a floating type that can move in the surface direction with respect to the backing plate 18, and a lever 54 and a strut 56 that are connected to each other by a connecting pin 52 so as to be relatively rotatable. The connecting pin 52 is arranged in a posture that is substantially parallel to the backing plate 18. The lever 54 is composed of two metal plates, and one end portion connected to the connecting pin 52 is integrally overlapped so as to be in close contact with each other and engaged with the brake shoe 24. On the other hand, the other end portions are separated from each other by a predetermined dimension, and a cable latching portion 64 for latching a latching member 62 fixed to the tip of the parking brake cable 60 is provided. The strut 56 is also composed of two metal plates. A lever 54 is disposed on the inner side of the strut 56, and the other end opposite to the connecting pin 52 is bent inward so as to be in close contact with each other. An engaging recess 66 is provided that is superimposed and engaged with the brake shoe 22. The lever 54 is provided with a leaf spring 68 bent in a predetermined shape to guide the parking brake cable 60 to the cable latching portion 64 of the lever 54 and to be temporarily inserted into the cable latching portion 64. The stop member 62 is not separated.

  In addition, between one end of the pair of brake shoes 22, 24, a fixing portion 72 a of the anchor member 72 is attached to a vehicle body side member such as an axle housing or a suspension device together with the backing plate 18 by two bolts 70. It is fixed integrally. Further, the expansion device 26 is supported in contact with the heads 70h of the bolts 70, and the fixing portions 72a of the anchor member 72 and the backing plate 18 have insertion holes 72b and 18a for inserting the parking brake cable 60. Is provided. A guide pipe 74 that accommodates the parking brake cable 60 on the inner peripheral side is inserted through these insertion holes 72b and 18a and is caulked to them.

  In the expansion device 26 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 lever 54 rotates in the direction of arrow F around the connecting pin 52. Accordingly, the pair of brake shoes 22, 24 are expanded, and the linings 44, 46 of the pair of brake shoes 22, 24 are in sliding contact with the inner peripheral surface 16 of the brake drum 14.

  When the linings 44 and 46 of the pair of brake shoes 22 and 24 are in contact with the inner peripheral surface 16 of the brake drum 14, if the brake drum 14, that is, the wheel attempts to rotate in the direction of arrow G shown in FIG. The brake shoes 22, 24 try to rotate together with the brake drum 14, but one end portion 36 a of the shoe web 36 of the brake shoe 22 abuts against the anchor member 72 and the pair of brake shoes 22, 24 are received by the anchor member 72. Brakes the wheel rotation. On the other hand, when the operating force from the parking brake lever in the pulling direction is returned, the pair of brake shoes 22 and 24 are reduced in diameter according to the urging force of the return spring 28 and the linings 44 and 46 of the pair of brake shoes 22 and 24 are reduced. Is separated from the inner peripheral surface 16 of the brake drum 14.

  FIGS. 3 and 4 are views for explaining the brake shoe 22. According to FIGS. 3 and 4, an anchor member is provided on one end portion 36a of the shoe web 36 during braking of the drum brake 10 so as to brake the wheel. Since a high load force is input from 72, one end portion 36a of the shoe web 36 is thickened as shown in FIG. 4 to withstand the high load. Hereinafter, a method for manufacturing the shoe web 36 will be described with reference to FIGS.

  FIG. 5 is a diagram showing a manufacturing process until the shoe web 36 shown in FIG. In FIG. 5, in the pressing step P1, a long plate member 76 (shoe web 36) in which a steel plate having a uniform thickness is formed into an arc shape and a flat plate shape as shown in FIG. Is done.

  In the subsequent bending step P2, one end portion 76a of the long plate member 76 is bent to bend the tip end of the one end portion 76a in the thickness direction of the long plate member 76 as shown in FIG. In addition, the bending amount A at which the tip of the one end 76a of the long plate member 76 is bent in the thickness direction of the long plate member 76a is set to be equal to or less than the plate thickness B of the long plate member 76. Is. One end 76a of the long plate member 76 shown by the solid line in FIG. 7 shows the state before the bending step P2, and one end 76a of the long plate member 76 shown by the one-dot chain line in FIG. 7 shows the state after the bending step P2. It is shown.

  The upper part of FIG. 8 is a diagram showing a state in which the long plate member 76 formed by the pressing step P1 and the bending step P2 is attached to the thickening portion forming device 78. The thickened portion forming apparatus 78 increases the thickness of the plate so that it can withstand high load input during braking by upsetting the one end portion 76a of the long plate member 76 whose one end portion 76a is bent by the bending step P2. A holding mold 80 for holding the long plate member 76 and a pressurizing mold 82 for pressing one end 76a of the long plate member 76 in the arrow H direction are provided.

  Returning to FIG. 5, in the thickened portion forming step P <b> 3, as shown in the lower stage of FIG. 7, when the pressing die 82 presses the one end portion 76 a of the long plate member 76 in the arrow H direction, The portion 76a tends to be deformed so as to spread in the plate thickness direction of the long plate member 76, but the bending of the tip of the one end portion 76a of the long plate member 76 is suppressed by the inner peripheral wall 80a of the holding mold 80. The side opposite to the bending direction in which the tip is bent by P2 is increased in thickness as shown in the lower stage of FIG. 7, and the plate thickness of the one end 76a of the long plate member 76 is increased.

  As described above, the end portion 76a of the long plate member 76 is bent in the thickness direction of the long plate member 76 by the bending step P2, so that the width in the thickness direction of the long plate member 76 is increased, and the thickened portion. By performing the upsetting process in a state where the tip is bent in the thickness direction of the long plate member 76 by the molding step P3, the opposite side to the bending direction is increased and the plate thickness is increased. That is, by increasing the thickness of the one end portion 76a of the long plate member 76 by bending the one end portion 76a of the long plate member 76 in the bending step P2 first, the upsetting process in the subsequent thickening portion forming step P3. Compared to conventional products that increase the thickness of the end of the long plate member so that it can withstand the high load input during braking, the thickness is reduced only by pressing, so the quenching process and large size of the high load are reduced. The plate thickness of one end of the long plate member can be increased so as to withstand the input of a high load during braking without using a press machine or the like. Further, since the quenching process or a large press machine with a high load is not used to increase the thickness of the one end 76a of the long plate member 76, the manufacturing cost of the long plate member 76, that is, the shoe web 36 is reduced. Can do.

  Further, as described above, in the one end portion 76 a of the long plate member 76, the bending amount A by which the tip of the one end portion 76 a is bent in the thickness direction of the long plate member 76 is equal to the plate thickness B of the long plate member 76 or Since it is set to be less than that, if the thickness opposite to the bending direction in which the tip end of the one end portion 76a of the long plate member 76 is bent by the bending step P2 in the thickening portion forming step P3, the anchor is fixed when the drum brake 10 is braked. Since the center position of the load input from the member 72 to the one end portion 76 a of the long plate member 76 can be within the plate thickness of the flat plate-like long plate member 76 in the thickness direction of the long plate member 76, the long plate member 76. The strength of the one end portion 76a can be suitably improved.

  In the thickened portion forming step P3 of the present embodiment, the bending step is not performed because a thickening amount to increase the thickness of the one end portion 76a of the long plate member 76 is small because a quenching step or a high-load large press machine is not used. If the amount A exceeds the plate thickness B of the long plate member 76, the center position of the load input from the anchor member 72 to the one end portion 76a of the long plate member 76 during braking of the drum brake 10 cannot be set to a predetermined position.

  Returning to FIG. 5, in the curing step P4, the end surface 76b of the one end portion 76a of the long plate member 76 formed in the thickened portion forming step P3 is struck with a die by press working, so that the hardness of the surface of the end surface 76b is 350 HV. About 400 HV. Therefore, the strength of the one end portion 76a of the long plate member 76 is preferably improved. Further, the long plate member 76 manufactured by the pressing step P1, the bending step P2, the thickened portion forming step P3, and the curing step P4 is the shoe web 36 shown in FIG. This is one end portion 36 a of the shoe web 36.

  Here, according to the drum brake 10 of the present embodiment, (f) the brake shoe 22 has a circular and flat shoe web 36, and (g) the shoe web 36 has its one end 36a at the time of braking. The brake shoe 22 is received by the anchor member 72 by being brought into contact with the anchor member 72. (h) One end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36) has a long tip. Since the upsetting process is performed in a state where the plate member 76 (shoe web 36) is bent in the thickness direction, the thickness of the plate member 76 (shoe web 36) is increased on the side opposite to the bending direction. One end portion 76a (one end portion 36a) of 36) is bent in the thickness direction of the long plate member 76 (shoe web 36), whereby the width in the thickness direction of the long plate member 76 (shoe web 36) is increased. ,in front Tip the plate thickness Once Zoniku on the opposite side is thicker of its bending direction by upsetting in a state bent in the thickness direction of the long plate member 76 (the shoe web 36) is subjected. That is, by first bending one end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36), the one end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36) is obtained by subsequent upsetting. Compared to the conventional type, which increases the plate thickness at one end of the long plate member (shoe web) to withstand the high load input during braking. Therefore, one end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36) can withstand the input of a high load at the time of braking without using a quenching process or a large press machine with a high load. The plate thickness can be increased. Further, in order to increase the thickness of the one end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36), a long plate member 76 (shoe shoe) is not used because a quenching process or a large press machine with high load is not used. The production cost of the web 36) can be reduced.

  Further, according to the drum brake 10 of the present embodiment, at the one end portion 76a (one end portion 36a) of the long plate member 76 (shoe web 36), the tip is bent in the thickness direction of the long plate member 76 (shoe web 36). Since the bending amount A is equal to or less than the plate thickness B of the long plate member 76 (shoe web 36), one end portion 76a (one end portion) of the long plate member 76 (shoe web 36) from the anchor member 72 during braking is applied. The center position of the load input to 36a) can be within the plate thickness of the flat plate member 76 (shoe web 36) in the thickness direction of the long plate member 76 (shoe web 36).

  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. However, the present invention can be applied to a drum brake of a two-leading type or a leading / trailing type. That is, the present invention can be applied to any type of drum brake as long as one end portion of the shoe web abuts on the anchor member during drum brake braking.

  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 14: Brake drum (rotating drum)
16: Inner peripheral surface 18: Backing plate 22, 24: A pair of brake shoes 36, 38: Shoe web 72: Anchor member A: Bending amount bent in the thickness direction of the long plate member (shoe web) B: Long plate member ( Thick web) thickness

Claims (2)

A backing plate, a pair of arc-shaped brake shoes disposed on the backing plate so as to be expandable, and an anchor member fixed to the backing plate so as to abut one end of the pair of brake shoes And a bottomed cylindrical rotating drum that rotates integrally with the wheel, by expanding the pair of brake shoes and sliding the pair of brake shoes on the inner peripheral surface of the rotating drum, A drum brake for a vehicle that brakes rotation of the wheel,
The brake shoe has a circular and flat shoe web,
The shoe web is such that the brake shoe is received by the anchor member by bringing its one end into contact with the anchor member during braking,
One end portion of the shoe web is thickened to the opposite side to the bending direction by being subjected to an upsetting process in a state where the tip is bent in the thickness direction of the shoe web. Drum brake for vehicles.   The vehicular drum brake according to claim 1, wherein a bending amount at which the tip is bent in a thickness direction of the shoe web at one end portion of the shoe web is equal to or less than a plate thickness of the shoe web. .

Images