JP2002021893A - Anchor for drum brake and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor for a drum brake reducing a manufacturing cost and improving productivity. SOLUTION: A pair of dowels 39 serving as rivets for connecting the anchor 33 to a backing plate 38 are integrally formed at an anchor body 34, being cylindrically embossed from one face of the anchor body 34 blanked from a plate-like base material into outer enclosure shape from the top view of the integrated anchor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum brake anchor having a shoe contact surface at both ends with which the ends of a brake shoe contact, and a method of manufacturing the same.
The present invention relates to an anchor capable of realizing a reduction in manufacturing cost and an improvement in productivity and a method for manufacturing the anchor.

[0002]

2. Description of the Related Art FIGS. 9 to 11 show the structure of a conventional drum brake anchor. As shown in these figures, the anchor 1 of the conventional drum brake has a shoe contact surface 5a with which the ends of the brake shoes 3 and 4 abut.
An anchor body 5 having both ends 5b and a shoe contact surface 5
a, 5b projecting from the upper edges of the shoe contact surfaces 5a, 5b
And a shoe retainer 7 for holding the edges of the brake shoes 3 and 4 which are in contact with the backing plate 10. The anchor body 5 and the shoe retainer 7 are further separated by a rivet 9 to form a backing plate 10. There is known a configuration in which the components are fixed in a co-fastened state. However, the anchor 1 having the above-described configuration has a large number of components and not only increases the manufacturing cost, but also requires a lot of trouble such as positioning of the components in assembling to the backing plate 10.
There is a problem that a process is required, which hinders improvement in productivity of the drum brake.

[0003] Therefore, as shown in FIG.
Assuming an anchor outer shape 14 in a side view of an integrated structure product in which an anchor main body and a rivet are united on the anchor 2 and punching out the anchor outer shape 14 in a side view by press working, an arrow (FIG. The flange 16 serving as a shoe retainer is formed by performing crush molding on the portion indicated by a), and the cross-sectional shape of the protrusion 19 indicated by an arrow (b) is formed from a square to a circle, thereby forming a rivet. An anchor manufacturing method has been proposed in which a dowel is formed to obtain an anchor 20 having a structure in which the anchor main body 14a, the shoe retainer 14b, and the rivet 14c are integrated (Japanese Utility Model Laid-Open No. 59-16323).
No. 7).

In the anchor 20 in which the anchor body 14a, the shoe retainer 14b, and the rivet 14c are integrated, it is not necessary to adjust the relative position between the anchor body 14a and the shoe retainer 14b when assembling the backing plate. As a result, the work of assembling to the backing plate becomes easy. Also, parts management is facilitated because it is composed of a single part.

[0005]

However, as shown in FIG. 12, the anchor outer shape 14 in a side view is changed to a plate-like base material 12.
In the method of manufacturing an anchor from which a blank is punched, the large depth dimension of the upper surface of the anchor must be the thickness of the plate-shaped base material 12, so that the plate thickness of the plate-shaped base material 12 becomes large, and only the punching process becomes difficult. In addition, since a large-sized press working device is required, there has been a problem that the working cost rises and the manufacturing cost rises. Also, since the punching is performed with the anchor outer shape 14 in a side view, the protrusion 1 serving as a dowel is formed.
In order to correct the cross-sectional shape to a circle, a work process of changing the direction of the workpiece is required before the cross-sectional shape of the work 9 is performed. However, there is also a problem that efficient in-line processing for finishing a product cannot be performed by performing the method, and productivity is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and reduces the thickness of a plate-shaped base material to be used, thereby facilitating punching and, at the same time, making it possible to manufacture even a small press working device. Since the dowels used as rivets can be created with a circular cross section from the beginning, there is no need to change the cross-sectional shape of the dowels, and there is no need to change the direction of the workpiece during the processing process. An object of the present invention is to provide an anchor for a drum brake and a method for manufacturing the same, which can reduce the number of processing steps and can realize a reduction in manufacturing cost and an improvement in productivity.

[0007]

According to a first aspect of the present invention, there is provided a drum brake anchor according to the present invention, which has a shoe abutment surface at both ends thereof with which an end of a brake shoe abuts. In the anchor, a pair of cylindrical dowels serving as rivets for coupling the anchor to the backing plate are punched out from one surface of the anchor body to be integrally formed, and a recess corresponding to the cylindrical dowel is formed on the other surface of the anchor body. It is characterized by having been formed.

According to the above construction, the pair of dowels serving as rivets are formed by stamping out a cylindrical surface from one surface of the anchor body, so that the large depth dimension of the upper surface of the anchor is determined by the thickness of the plate-shaped base material. As compared with the case where the projection which becomes the dowel is punched from the plate-shaped base material, the punching can be easily performed without the need for a large-sized press working device. In addition, a desired columnar shape can be directly punched by a single press working and can be easily manufactured.

According to a second aspect of the present invention, in the drum brake anchor according to the first aspect, the recess is formed in a shape corresponding to the cylindrical dowel. It is characterized by.

According to the above configuration, since the recess is formed in a column shape corresponding to the dowel, a desired cylindrical dowel can be easily stamped and formed.

According to a third aspect of the present invention, there is provided a drum brake anchor according to the first aspect, wherein the anchor further extends from an upper edge of a shoe contact surface. It is characterized in that the brake shoe is integrally provided with a shoe retainer for preventing the brake shoe from floating from the backing plate.

According to this structure, since the anchor body, the shoe retainer and the rivet are integrated, it is not necessary to adjust the relative position between the anchor body and the shoe retainer when assembling the backing plate of the drum brake. The work of assembling to the backing plate becomes easy. Also, parts management is facilitated because it is composed of a single part.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a drum brake anchor according to the present invention, wherein the drum brake anchor has a shoe contact surface at both ends with which the ends of the brake shoes abut. In the method, a retainer forming portion formed so as to protrude from an upper edge of the shoe contact surface and formed into a shoe retainer, assuming a contour of a planar view of an anchor formed from a plate-shaped base material having a predetermined thickness. A rough cutting step of punching out unnecessary parts around the periphery by punching, and a pair of dowels serving as rivets for coupling the anchor to the backing plate are punched out in a cylindrical shape from one surface of the anchor body between the retainer forming portions, and concave on the other surface. A dowel forming step of forming a place, a crush forming step of crushing the retainer forming portion to a predetermined plate thickness as the shoe retainer, Comprising a pinch around punching step of excising unnecessary portions as the shoe retainer from overhanging portion formed by a molding process, a blank step for punching the contour of the anchor from the plate-shaped base member,
By sequentially performing each of these processing steps by a fine blanking processing method, the anchor in which the anchor body, the shoe retainer, and the cylindrical dowel are integrally formed is obtained.

[0014] Then, in the anchor manufacturing method having the above configuration,
In order to punch the outer shape of the integrated anchor in plan view from the plate-shaped base material, the large depth dimension of the upper surface of the anchor can be adjusted by the dimension in the plane direction of the plate-shaped base material. By minimizing the thickness of the plate base material to be used to the minimum necessary for the anchor body and reducing it to an appropriate thickness suitable for the fine blanking method, it is possible to facilitate It can also be manufactured with a press working device. Also, since the punching direction with respect to the plate-shaped base material coincides with the axial direction of the dowel formed by punching, the dowel used as a rivet can be formed in a circular cross section from the beginning, and the process of changing the cross-sectional shape of the dowel In addition, there is no need to change the handling of the workpiece during the machining process, such as for shaping the cross section of the dowel. Therefore, the number of processing steps can be significantly reduced, and a reduction in manufacturing cost and an improvement in productivity can be realized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a drum brake anchor and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings. 1 to 8 show an embodiment of a method for manufacturing a drum brake anchor according to the present invention, and FIG. 1 shows a drum brake using an anchor formed by the method for manufacturing an anchor according to the present invention. Front view,
2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is an exploded perspective view showing a state before the anchor is attached to the backing plate, FIG. 4 is a plan view of the integrated anchor shown in FIG. FIG. 6 is a front view of the integrated anchor, FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5, FIG.
FIG. 8 is a diagram illustrating a change in the cross-sectional shape of the plate-shaped base material during the pressing process illustrated in FIG. 7.

A drum brake 100 shown in FIG. 1 is a wheel cylinder for expanding a pair of brake shoes 3, 4 arranged opposite to each other in a drum, between the opposed ends thereof. 31 and between the other opposing ends of the pair of brake shoes 3 and 4
An integrated anchor 33 is provided which supports the ends of these brake shoes and receives an anchor reaction force. Each of the brake shoes 3 and 4 is urged in a direction approaching each other by shoe-to-shoe springs 32a and 32b so as to maintain a state in which each end is in contact with the wheel cylinder 31 and the anchor 33.

As shown in FIGS. 2 to 6, the anchor 33 has shoe contact surfaces 34a and 34b with which the ends of a pair of brake shoes 3 and 4 are in contact.
A shoe retainer 36 that protrudes from the upper edges of the shoe contact surfaces 34a, 34b and presses the edges of the brake shoes 3, 4 that are in contact with the shoe contact surfaces 34a, 34b; And the anchor body 3
4 comprises a pair of cylindrical dowels 39 serving as rivets for fixing the dowel 39 to the backing plate 38 and a recess 60 formed on the other surface of the anchor body 34 in a shape corresponding to the cylindrical dowel 39. After being fitted into an anchor mounting hole 38 a formed in the plate 38, the tip of the dowel 39 is crushed into a flat shape, so that the backing plate 38 is formed.
Fixed to

The above-described anchor 33 is manufactured by performing processing in the order of FIGS. 7A to 7I using a fine blanking processing method. The fine blanking method is a method that presses a metal plate to generate a hydrostatic pressure by applying three forces of shearing pressure, plate holding pressure, and back pressure to reduce the plastic deformability of the material. It is a precision punching process that can be improved, for example, when a finished surface is required over the entire punched cross section, so that the entire punched cross section can be finished at the same time in the pressing process.

The procedure for manufacturing the anchor 33 will be described below with reference to FIG. First, as shown in FIG. 7A, an outer shape 43 in plan view of an anchor 33 integrally formed on a plate-like base material 41 having a predetermined thickness is assumed, and a retainer which is a part to be formed on the shoe retainer 36. A rough cut step of cutting out unnecessary portions 46 around the formation portion 45 by punching is performed. By performing the rough cutting step, the unnecessary portion 46 of the plate-shaped base material 41 is cut off as shown in FIG. 7B and FIG. 8A which is a cross section taken along the line ii in FIG. 7B. It is formed into a cross-sectional structure. The plate-shaped base material 41 is a strip-shaped elongate member, and a pilot pierce 41a, which is a positioning hole at the time of press working, is formed in the vicinity of both sides at regular intervals along the longitudinal direction. The pilot 50 mounted on the press machine is fitted into the, so that the positioning of the plate-shaped base material 41 is achieved.

Next, as shown in FIG. 7C, a dowel 39 serving as a rivet is formed into a cylindrical shape from one surface of the portion serving as the anchor body 34 between the pair of retainer forming portions 45, and a recess 60 is provided on the other surface. A dowel forming step for forming is performed. When the dowel forming step is completed, FIGS. 7C and 7C
As shown in FIG. 8B, which is a cross section along the roll line, a cross-sectional structure in which the cylindrical dowel 39 protrudes from the anchor body 34 is obtained. Next, as shown in FIG. 7D, the previously formed retainer forming portion 45 is connected to the shoe retainer 36.
A crush molding step of crush molding to a suitable plate thickness is performed. When this crushing forming step is completed, FIG.
As shown in FIG. 8C, which is a cross section along the line C-E of FIG. 8E, a cross-sectional structure in which the overhang portion 48 including the shoe retainer 36 is formed is obtained.

Next, as shown in FIG. 7 (f), a step of punching around the crushed portion for cutting out an unnecessary portion from the overhang portion 48 as the shoe retainer 36 is performed, and FIG. 7 (g).
FIG. 8 (d) which is a cross-section along the line ii in FIG. 7 (g) and FIG.
As shown in (1), a cross-sectional structure in which the shoe retainer 36 is formed to protrude is obtained. When performing the step of punching around the crushed portion, an elongation preventing wedge 55 is driven into the plate-shaped base material 41 so that the periphery of the rear punched portion does not expand. Next, as shown in FIG. 7H, blanks are formed by punching the elongation preventing wedges 55 and 56 before and after the outer contour 43 in plan view, and then punching the outer contour 43 in planar view from the plate-shaped base material 41. Perform the process. When this blanking step is completed, the plate-shaped base material 41 is formed as shown in FIGS.
As shown in FIG. 8 (e), which is a cross section along the Hoho line of (i), the gathering area of the initially set outer shape 43 and the unnecessary part 46 in plan view is completely cut away.

The steps shown in FIGS. 7A to 7I are sequentially repeated, so that the anchor main body 34 and the shoe retainer 3 are formed at regular intervals from the band-shaped plate-like base material 41.
An anchor 33 integrally formed with the cylindrical dowel 39 and the cylindrical dowel 39 is stamped and formed.

An anchor 33 manufactured by the anchor manufacturing method shown in the present embodiment has a structure in which an anchor body 34, a shoe retainer 36, and a cylindrical dowel 39 serving as a rivet are integrated. It is not necessary to adjust the relative position between the anchor body 34 and the shoe retainer 36, and the assembling work to the backing plate 38 becomes easy. Also, parts management is facilitated because it is composed of a single part.

In the anchor manufacturing method having the above structure,
Since the outer shape 43 of the integrated anchor 33 in a plan view is punched from the plate-shaped base material 41, the large depth dimension of the upper surface of the anchor 33 can be matched with the dimension in the surface direction of the plate-shaped base material 41. The thickness of the plate is reduced to the minimum necessary for the anchor body 34, the thickness of the plate-like base material 41 to be used is reduced to an appropriate thickness suitable for the fine blanking method, and the punching process is facilitated. , And can be manufactured even with a small press working device.

Further, since the punching direction with respect to the plate-shaped base material 41 coincides with the axial direction of the dowel 39 formed by punching, the cylindrical dowel 39 used as a rivet can be formed in a circular cross section from the beginning. There is no need to change the cross-sectional shape of the dowel 39, and there is no need to change the handling of the workpiece during the processing process for forming the cross-sectional shape of the dowel 39. Therefore, the number of processing steps can be significantly reduced, and a reduction in manufacturing cost and an improvement in productivity can be realized.

[0026]

As described above, in the anchor manufactured by the method of manufacturing an anchor for a drum brake according to the present invention, a pair of cylindrical dowels serving as rivets are punched out from one surface of the anchor body to form a recess in the other surface. Since the large depth dimension of the upper surface of the anchor is set to the plate thickness of the plate-shaped base material, the projection that becomes a dowel is punched out from the plate-shaped base material. It can be done easily. In addition, a desired columnar shape can be directly punched by a single press working and can be easily manufactured. Also, because the anchor body, shoe retainer and rivet are integrated, there is no need to adjust the relative position between the anchor body and shoe retainer when assembling the backing plate.
The work of assembling to the backing plate becomes easy. Also, parts management is facilitated because it is composed of a single part.

In the anchor manufacturing method according to the present invention, since the outer shape of the integrated anchor in plan view is punched from the plate-shaped base material, the large depth dimension of the upper surface of the anchor is matched with the dimension in the plane direction of the plate-shaped base material. The plate thickness of the plate base material can be reduced to the minimum required for the anchor body, and the plate thickness of the plate base material used can be reduced to an appropriate plate thickness suitable for the fine blanking processing method. As a result, the punching process can be facilitated, and the device can be manufactured even with a small press working device. Also, since the punching direction with respect to the plate-shaped base material coincides with the axial direction of the dowel formed by punching, the dowel used as a rivet can be formed in a circular cross section from the beginning, and the process of changing the cross-sectional shape of the dowel In addition, there is no need for a handling change operation for changing the direction of the workpiece between processing steps for forming the cross section of the dowel or the like. Therefore, the number of processing steps can be significantly reduced, and a reduction in manufacturing cost and an improvement in productivity can be realized.

[Brief description of the drawings]

FIG. 1 is a front view of a drum brake using an anchor formed by a method for manufacturing an anchor according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an exploded perspective view showing a state before the anchor shown in FIG. 2 is attached to a backing plate.

FIG. 4 is a plan view of an integrated anchor.

FIG. 5 is a front view of the integrated anchor.

6 is a sectional view taken along the line VI-VI in FIG.

FIG. 7 is an explanatory view of a press working step sequence according to the present invention.

8A and 8B are explanatory views of a change in the cross-sectional shape of the plate-shaped base material during each press working step of FIG. 7; FIG. 8A is a cross-sectional view taken along the line II-II of FIG. FIG. 7C is a sectional view taken along the line C-C in FIG. 7C, FIG. 7C is a sectional view taken along the line C-E in FIG.
FIG. 7D is a cross-sectional view taken along the line II-II in FIG. 7G, and FIG. 7E is a cross-sectional view taken along the line Ho-ho in FIG. 7I.

FIG. 9 is a front view of a main part of a drum brake using an anchor according to a conventional manufacturing method.

FIG. 10 is a sectional view taken along the line XX of FIG. 9;

11 is an exploded perspective view of the anchor shown in FIG.

FIG. 12 is a perspective view showing a method of manufacturing a conventional integrated anchor.

FIG. 13 is an explanatory diagram of a portion that is difficult to process when manufacturing by the anchor manufacturing method illustrated in FIG. 12;

[Explanation of symbols]

 3, 4 Brake shoe 33 Anchor 34 Anchor body 34a, 34b Shoe contact surface 36 Shoe retainer 38 Backing plate 39 Dowel 41a Pilot pierce 43 Outer shape in plan view 45 Retainer forming portion 46 Unnecessary portion 48 Overhang 50 Pilot 55, 56 Elongation Prevention wedge 60 recess

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Yamada 19-5 Nihonbashi Koami-cho, Chuo-ku, Tokyo Inside Akebono Brake Industry Co., Ltd. (72) Katsuhiro Yamamoto 88-26 Shingo, Higashimatsuyama-shi, Saitama Inside Yamamoto Works (72) Takashi Shimizu Inventor 88-26 Shingo, Higashimatsuyama City, Saitama Prefecture Yamamoto Works F Term (Reference) 3J058 BA61 CA18 CA22 CA25 DD20 EA02 EA31

Claims (4)

[Claims] 1. An anchor for a drum brake having, at both ends, a shoe abutting surface with which an end of a brake shoe abuts, a pair of cylindrical dowels serving as rivets for connecting the anchor to a backing plate are provided on one surface of the anchor body. An anchor for a drum brake, wherein the anchor is formed integrally by punching out, and a recess corresponding to the cylindrical dowel is formed on the other surface of the anchor body. 2. The drum brake anchor according to claim 1, wherein the recess is formed in a shape corresponding to the cylindrical dowel. 3. The shoe according to claim 1, wherein said anchor further includes a shoe retainer formed so as to protrude from an upper edge of the shoe contact surface to prevent the brake shoe from floating from the backing plate. Drum brake anchor described. 4. A method of manufacturing an anchor for a drum brake having a shoe abutment surface at both ends with which an end of a brake shoe abuts, wherein an outer shape of the anchor in plan view formed of a plate-shaped base material having a predetermined thickness is provided. Assuming that a rough cutting step of punching out an unnecessary portion around a retainer forming portion formed to protrude from the upper edge of the shoe contact surface and formed into a shoe retainer by punching, and for coupling an anchor to a backing plate. A dowel forming step of punching a pair of dowels to be rivets from one surface of the anchor body between the retainer forming portions into a cylindrical shape and forming a recess on the other surface; and forming the retainer forming portion as the shoe retainer to a predetermined plate thickness. Crushing step of crushing, and cutting out an unnecessary portion as the shoe retainer from the overhang formed by the crushing step. A punching step around the crushed portion, and a blanking step of punching the outer shape of the anchor from the plate-shaped base material, by sequentially performing each of these processing steps by a fine blanking processing method, the anchor body and A method of manufacturing an anchor for a drum brake, comprising obtaining the anchor in which the shoe retainer and the cylindrical dowel are integrally formed.