JP2003240031A - Cable guide of drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a small and light cable guide at a low cost, even when an outer casing is not connected. <P>SOLUTION: In the cable guide 56, an engaging part 72 is engaged with the inside of a mounting hole 70 from the inside of a backing plate 10, and a flange part 74 integrally disposed to project from the engaging part 72 to the outer peripheral side is adhered closely to the inner surface of the backing plate 10, namely the peripheral edge of the mounting hole 70. Therefore, though an outer casing is not disposed and outside directional load (downward of Fig. 3 (b)) is charged in pulling a brake cable 50, the flange part 74 keeps a good mounting state to the backing plate 10, and one relatively small screw 78 simply allows certain and undetachable fixing. Thus, the small and light cable guide 56 can be constituted at the low cost. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum brake, and more particularly to a cable guide for inserting a brake cable for generating a braking force into and out of the drum brake.

[0002]

2. Description of the Related Art A drum brake in which a brake shoe disposed on a backing plate is mechanically pressed against a rotating drum by a brake cable to generate a braking force is used for a vehicle parking brake or the like. In such a drum brake, the structure for introducing the brake cable from the back of the backing plate into the drum brake is usually configured as shown in FIG. 6 or 7. FIG. 6 shows the backing plate 1
00 has a mounting hole 102 formed in the flat portion thereof, and a cable guide 104 is fitted from the outside (the lower side of FIG. 6B) and integrally fixed by a bolt 106, and is tilted with respect to the backing plate 100. Cable guide 10
The brake cable 11 is inserted into the insertion hole 108 provided in
0 is inserted and introduced into the drum brake. The brake cable 110 is arranged substantially parallel to the backing plate 100 and is connected to the brake lever. When a tensile force is applied to the brake cable 110, the brake cable is rotated to generate a braking force. Around the circumference, a return spring (compression coil spring) 11 that returns the brake lever to its original position.
2 are arranged concentrically, and one end of the cable guide 10 is provided.
It is seated in 4. Also, the brake cable 11
The outer casing 1 is inserted through the outer casing 114 and guided from a brake operating member such as an operating lever, which is a tensile force applying side, to a drum brake.
The end of 14 is fixed to the cable guide 104, and is positioned on the vehicle body or the like by a clamp 116 in the vicinity thereof. 6A is a front view seen from the inside of the drum brake in a direction perpendicular to the backing plate 100 and in which brake shoes and the like are arranged, FIG.
FIG. 7B is a sectional view taken along line BB in (a).

In this case, since the direction of the brake cable 110 changes outward in the insertion hole 108 portion, the brake operating member is operated and the brake cable 1 is operated.
When 10 is pulled in the lower right direction in FIG. 6 (b), a load is applied to the cable guide 104 in the direction outward from the backing plate 100 (downward in FIG. 6 (b)). Are relatively pressed against the backing plate 100 by the outer casing 114 to cancel each other, so that the fixing state with respect to the backing plate 100 is favorably maintained even with only one bolt 106.

Further, FIG. 7 shows an inclined portion 12 which is substantially perpendicular to the posture of the brake cable 110, that is, the pulling direction.
0 is provided on the backing plate 100 by drawing,
The cable guide 12 is substantially perpendicular to the inclined portion 120.
2, the cable guide 122 is provided with a plurality of locking claws 124, and the cable guide 122 is inserted from the outside into a mounting hole 126 provided in the inclined portion 120, so that the one-touch operation is performed via the locking claws 124. Is attached to the backing plate 100 in a non-separable manner.

[0005]

By the way, in recent years, it has been considered that the brake cable is divided into a first cable on the drum brake side and a second cable on the tensile force applying side. In that case, The first cable on the drum brake side extends outward from the backing plate without the outer casing. Therefore, the effect of pressing the cable guide 104 against the backing plate 100 by the outer casing 114 as shown in FIG. 6 cannot be obtained, and it is necessary to increase the mounting strength of the cable guide 104.
For example, enlarging the flange and tightening bolts at multiple points.
There is a problem that the cable guide 104 is large and heavy, and the cost is high.

As shown in FIG. 7, when the pulling direction of the brake cable 110 and the posture of the cable guide 122 are substantially the same, a large load is not applied to the cable guide 122 when pulling the brake cable 110, and the outer casing 114 is not. It is also suitable for the case where the backing plate 100 is not connected, but since it is necessary to perform a severe drawing process on the backing plate 100, it is necessary to increase the number of manufacturing steps of the backing plate 100 and the material is restricted, resulting in high cost. was there.

The present invention has been made in view of the above circumstances, and it is an object of the present invention that a strict drawing process for a backing plate is unnecessary and a cable guide can be made compact even when an outer casing is not connected. Therefore, it is to be able to be configured with a light weight and a low cost.

[0008]

In order to achieve such an object, the first aspect of the present invention is that a brake shoe disposed on a backing plate is mechanically pressed against a rotating drum by applying a tensile force to a brake cable. In a drum brake that generates a braking force by means of a cable guide, the cable guide is integrally fixed to the backing plate to insert the brake cable into and out of the drum brake, and (a) an attachment provided on the backing plate. In the hole, while being fitted from the inside of the backing plate, a fitting portion having an insertion hole through which the brake cable is inserted, and (b) integrally provided so as to protrude from the fitting portion to the outer peripheral side, A flange portion that is a peripheral portion of the mounting hole and is brought into contact with an inner surface of the backing plate. And wherein the Rukoto.

A second invention is the cable guide for a drum brake according to the first invention. (A) The brake cable is divided into a first cable on the drum brake side and a second cable on the tension applying side. Cage, (b) the first
The cable is characterized in that it extends to the outside of the backing plate without an outer casing.

A third invention is the cable guide for the drum brake according to the first invention or the second invention, wherein (a) the brake cable is arranged substantially parallel to the backing plate inside the drum brake, and In the cable guide portion, the direction is changed outward, and (b) a load acting in an outward direction acts on the cable guide when the brake cable is pulled.

[0011]

In such a cable guide,
The fitting part having the insertion hole is fitted into the mounting hole from the inside of the backing plate, and the flange part integrally provided so as to project from the fitting part to the outer peripheral side is
Even if there is no outer casing and a load in the outward direction is applied when the brake cable is pulled because it is in contact with the inner surface of the backing plate at the peripheral edge of the mounting hole, the flange portion can be attached to the backing plate. The condition is maintained well, and the cable guide can be configured to be small, lightweight and inexpensive. Also,
The backing plate does not necessarily need to be subjected to severe drawing, which simplifies the backing plate drawing process and increases the degree of freedom in setting the material.
Also in this respect, the cost can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to, for example, (a) a pair of arc-shaped brake shoes arranged substantially symmetrically on a backing plate so that they can approach and separate from each other, and (b) one of the pair of brake shoes. A brake lever connected to the backing plate so as to be relatively rotatable about an axis substantially perpendicular to the backing plate, and (c) a strut disposed across the brake lever and the other brake shoe, Have
(d) The brake cable connected to the brake lever is pulled in a direction substantially parallel to the backing plate to rotate the brake lever, so that the pair of brake shoes are separated from each other via the strut,
It is preferably applied to a vehicle brake device for a parking brake or a service brake that is pressed by a rotary drum arranged on a wheel to generate a braking force, but other than a vehicle brake device such as a toggle type or other vehicle. It can also be applied to the drum brake of the above braking device. The engaging structure between the brake lever and the brake shoe and the engaging structure between the brake lever and the strut may be connected by a connecting pin or the like which is substantially vertical to the backing plate, but a spring or the like while positioning by a notch or the like. It suffices to just make contact with each other so as to be relatively rotatable.

The cable guide can be fixed to the backing plate only by, for example, tight fitting of the fitting portion into the mounting hole, but a screw and a nut are used with the flange portion abutting the inner surface of the backing plate. Fixing the flange part to the backing plate, caulking the tip of the protrusion that is integrally provided on the flange part and protrudes from the through hole of the backing plate, or attach a toothed disc spring washer to the protrusion, It is also possible to use a separate fixing means, such as attaching a predetermined retaining member to the fitting portion protruding from the attachment hole, to fix the fitting portion to the backing plate in a non-falling manner. Although one fixing means may be provided, a plurality of fixing means may be provided if necessary. The shape of the mounting hole provided in the backing plate is preferably substantially the same as the shape of the fitting portion, but there may be a gap.

The insertion hole provided in the fitting portion is provided so as to be inclined with respect to the backing plate, for example.
Various modes are possible, such as an insertion hole that is substantially perpendicular to the backing plate. The flange portion is preferably provided on the entire circumference of the fitting portion, but may be provided separately in the circumferential direction such as a radial shape.

In the cable guide of the present invention, the brake cable is divided into the first cable on the drum brake side and the second cable on the tensile force applying side, and the first cable extends to the outside of the backing plate without the outer casing. It is applied when the brake cable is pulled out and there is a load acting in the outward direction when the brake cable is pulled, but when the brake cable is composed of a single cable or the outer casing is connected to the cable guide. If
Alternatively, the cable guide of the present invention can be used even when a load in the outward direction hardly acts when pulling the brake cable. Each of the first cable and the second cable of the second invention may be further composed of a plurality of cables.

The backing plate is mainly composed of a flat surface portion substantially parallel to a reference plane of the drum brake where the pair of brake shoes approach and separate, that is, a plane perpendicular to the rotation center line of the rotary drum. The cable guide is also provided, for example, on the flat surface portion, but it may be provided on a portion inclined with respect to the reference plane by performing drawing processing or the like.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a parking brake device 2 for a vehicle to which the present invention is applied. A leading / trailing type drum brake 4 is provided near a wheel, and a driving / seat is provided near a driver's seat. Control lever 6
And a brake cable 8 connecting them, and when the operating lever 6 is pulled up, a pulling force is applied to the brake cable 8 to mechanically operate the drum brake 4, which is not shown. Apply braking force to the wheels. The drum brake 4 is a brake operating portion, and the operating lever 6 is a parking brake operating member that applies a pulling force.

The drum brake 4 is used as a parking brake and a regular brake. The drum brake 4 is provided with a backing plate 10 fixedly mounted on a vehicle body side member that rotatably supports wheels, and the backing plate 10 has a backing plate 10. Is provided with a pair of brake shoes 12 and 14 that are arcuate so as to be able to expand each other by shoe hold down devices 16 and 18. The backing plate 10 is mainly configured by a disc-shaped flat surface portion parallel to a reference plane (a plane parallel to the paper surface of FIG. 1) of the drum brake 4 where the pair of brake shoes 12 and 14 approach and separate. One end (upper end) of the pair of brake shoes 12, 14 is engaged with both ends of the wheel cylinder 26 fixed to the backing plate 10, respectively, and is a service brake operating member during braking of the service brake. When the brake pedal is stepped on, the wheel cylinders 26 expand the brake pedals in the directions in which they are separated from each other and are pressed by the rotating drum 27 that rotates with the wheels to generate a braking force. At a position near the wheel cylinder 26 and on the inner peripheral side of the backing plate 10,
A return spring (tensile coil spring in this embodiment) 28 is stretched across the brake shoes 12 and 14, and is biased toward each other, and a strut 30 is inserted through the return spring 28. Is provided, and the return spring 28 is
The approach position (standby position) of the pair of brake shoes 12 and 14 that are brought closer to each other according to the urging force of is defined. The other ends (lower ends) of the brake shoes 12 and 14 are brought into contact with the anchors 32 fixed to the backing plate 10.

A brake lever 34 is attached to an end of one of the brake shoes 12 on the wheel cylinder 26 side so as to be rotatable about an axis of an attachment shaft 36 which is substantially vertical to the backing plate 10. Strut 3
0 is disposed so as to straddle the brake lever 34 and the other brake shoe 14. Brake lever 34
The brake cable 8 is connected to the tip portion (lower end portion) of the brake cable 8 when the operation lever 6 is operated.
Is pulled to the right in FIG. 1, the brake lever 34
Is rotated to the left of the mounting shaft 36, and the strut 3
When the brake shoe 14 is moved to the right via 0, the brake shoe 14 is pressed by the rotating drum 27 to generate a braking force, and the brake shoe 12 is moved to the left together with the mounting shaft 36 by a reaction, and the rotating drum is rotated. It is pressed by 27 to generate a braking force. The brake lever 34 is provided for the return spring 2 when the parking brake is not operated.
By the action of 8 and 38, the engagement protrusion 34a is held in a fixed original position in which it is brought into contact with the shoe rim of the brake shoe 12,
The approach position of the brake shoe 12 is defined by the strut 30 via the brake lever 34. Strut 3
0 is that the adjuster wheel 40 provided in the middle portion is rotated in one direction by the shoe gap automatic adjusting mechanism 42 so as to be extended by the action of the screw, and the pair of brake shoes when not braking. 1
The approaching positions of 2 and 14 are separated from each other, so that the brake shoes 12 and 14 and the rotating drum 27 are not affected by wear of the lining.
The shoe clearance between them and (the sum of both) is kept substantially constant.

The brake cable 8 is composed of a first cable 50 connected to the brake lever 34 and a second cable 52 connected to the operation lever 6, and the first cable 50 and the first cable 50 are connected to each other. 2 cable 52
Are integrally connected by a cable connector 54 near the drum brake 4. The first cable 50 is passed through a cable guide 56 provided on the backing plate 10 and extends to the back side (outside) of the backing plate 10 without an outer casing, while the second cable 52 is an outer casing not shown. It is inserted through and is guided to the vicinity of the drum brake 4. Before assembling the drum brake 4 to the vehicle, the first cable 50 has the other end connected to the brake lever 34 in a state where the end on the connection side extends from the cable guide 56 to the back side.
After the drum brake 4 is assembled to the vehicle, it is connected to the second cable 52 via the cable connecting member 54. The first cable 50 has a nylon coating.

FIG. 2 shows an example of the cable connector 54 having a substantially C-shaped cross section and a pair of side wall portions 5.
8 and 60 are provided with notched hole-shaped locking portions 62 and 64, respectively, and a cylindrical cable end 5 integrally fixed to the connection side end portions of the first cable 50 and the second cable 52.
0e and 52e are locked to the locking portions 62 and 64, respectively, so that the first
The cable 50 and the second cable 52 are integrally connected so as to prevent them from being separated from each other. The cable connecting member 54 is made of an elastically deformable metal plate material such as spring steel, and the opening side (upper side of the drawing) of the side wall parts 58 and 60 is connected at the time of connecting work as shown in FIG. 2 (b). The cable ends 50e and 52e may be fitted into the locking portions 62 and 64 while being expanded by the cable ends 50e and 52e.

FIG. 3 is a view for explaining the cable guide 56. (a) is a front view corresponding to FIG. 1 (a), (b) and
(c) is a BB sectional view and a CC sectional view in (a), respectively. The cable guide 56 is disposed on a flat surface portion that forms the main body of the backing plate 10, and has a fitting portion 72 fitted into a mounting hole 70 provided in the backing plate 10, and an outer periphery from the fitting portion 72. And a flange portion 74 integrally provided so as to project to the side. The fitting portion 72 is fitted into the mounting hole 70 from the inside of the backing plate 10, that is, from above in FIG. 3 (b) without any gap, and the flange portion 74 is the peripheral portion of the mounting hole 70 and inside the backing plate 10. The one side screw 78, which is a fixing means, penetrates the flange portion 74 and the backing plate 10 and is screwed into the nut 80, so that the cable guide 56 is attached. It is integrally fixed to the backing plate 10. The flange portion 74 is provided continuously at one end portion of the fitting portion 72, that is, the end portion located inside the backing plate 10 over the entire circumference thereof. The nut 80 is integrally fixed to the back (outer) surface of the backing plate 10 in advance by projection welding or the like.

In the fitting portion 72, the first cable 5
The backing plate 1 has an insertion hole 82 through which 0 is inserted.
The first cable 50, which is provided so as to be inclined with respect to 0 and is arranged substantially parallel to the backing plate 10 inside the drum brake 4, changes its direction outward at the cable guide 56. , Extends obliquely outside the backing plate 10 through the insertion hole 82. Therefore, when the operation lever 6 is operated and the first cable 50 is pulled in the lower right direction of FIG. 3 (b), the cable guide 56 has a direction outward from the backing plate 10 (see FIG. 3 (b)). Under the direction)
Load. Further, a flat spring receiving seat surface 84 is provided in one opening of the insertion hole 82, that is, the opening located inside the backing plate 10, and
One end of the return spring (compression coil spring) 38 arranged so as to wind the cable 50 is seated.

As described above, the parking brake device 2 of this embodiment has the first cable 50 connected to the drum brake 4 and the second cable 5 connected to the operation lever 6.
Since the brake cable 8 is composed of 2,
After assembling the drum brake 4 in which the first cable 50 is connected to the brake lever 34 in advance to the vehicle, the first cable 50 extending from the drum brake 4 may be connected to the second cable 52 via the cable connector 54. The work of disposing the brake cable 8 is facilitated. That is,
Compared to the case where the drum brake 4 is attached to the vehicle using a single brake cable and then the brake cable is connected to the brake lever 34 of the drum brake 4, the work of attaching the brake cable becomes easier. .

On the other hand, in such a cable-split type parking brake device 2, since the cable guide 56 is not connected to the outer casing, when the brake cable 8 is pulled outside the cable guide 56 (see FIG. 3).
A downward load in (b) acts, but
In the cable guide 56 of this embodiment, the fitting portion 72 is fitted into the mounting hole 70 from the inside of the backing plate 10, and the flange portion 74 integrally provided so as to project from the fitting portion 72 to the outer peripheral side. But its mounting hole 7
Since it is the peripheral portion of 0 and is closely attached to the inner surface of the backing plate 10, the flange 74 maintains a good attachment state to the backing plate 10 regardless of the load in the outward direction, and a relatively small one Since it is possible to securely fix the cable guide 56 only with the screw 78 so that it cannot be removed, the cable guide 56 can be configured to be small, lightweight and inexpensive.

Further, unlike the cable guide 122 of FIG. 7, it is not necessary to perform a severe drawing process on the backing plate 10, so that the drawing process of the backing plate 10 can be simplified and the degree of freedom of material setting can be increased. Is also high, and cost can be reduced in this respect as well.

Although the cable guide 56 is fixed to the backing plate 10 by the screw 78 and the nut 80 in the above-mentioned embodiment, it is integrally provided on the flange portion 74 as shown in FIG. 4, for example. The toothed disc spring washer 90 is pushed into the tip portion of the cylindrical protrusion 88 protruding from the through hole 86 of the backing plate 10 to the opposite side (outside), or the tip portion of the protrusion 88 is fitted as shown in FIG. Various fixing means such as caulking and crushing can be adopted. Figure 4 (a)
5A and 5B are sectional views corresponding to FIG. 3C, and FIG. 4B is a bottom view of FIG. 4A viewed from below.

The embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely embodiments, and the present invention includes various modifications and improvements based on the knowledge of those skilled in the art. Can be implemented in.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a parking brake device to which the present invention is applied.

FIG. 2 is a diagram showing a cable connector of the parking brake device of FIG. 1, (a) is a perspective view of a connected state, and (b) is a view of connecting the first cable and the second cable to the cable connector. It is a perspective view explaining the procedure of.

3A and 3B are diagrams showing a cable guide of the parking brake device of FIG. 1, in which FIG. 3A is a front view corresponding to FIG. 1, and FIG.
(a) BB sectional drawing, (c) is CC in (a)
FIG.

FIG. 4 is a view showing another mode of fixing the cable guide of FIG. 3 to the backing plate, (a) is a cross-sectional view corresponding to FIG. 3 (c), and (b) is a bottom view of (a). FIG.

5 is a cross-sectional view corresponding to FIG. 3 (c), showing still another mode of fixing the cable guide of FIG. 3 to the backing plate.

6A and 6B are views for explaining a conventional cable guide, in which FIG. 6A is a front view and FIG. 6B is a sectional view taken along line BB in FIG.

FIG. 7 is a diagram showing another example of a conventional cable guide.

[Explanation of symbols]

2: Parking brake device 4: Drum brake
8: Brake cable 10: Backing plate 12, 14: Brake shoe 27: Rotating drum 50: First cable 52: Second cable 5
6: Cable guide 70: Mounting hole 72: Fitting portion 74: Flange portion 82: Insertion hole

Claims (3)

[Claims] 1. A drum brake in which a brake shoe disposed on a backing plate is mechanically pressed by a rotating drum to generate a braking force when a tensile force is applied to a brake cable, and the brake shoe is integrated with the backing plate. A cable guide that is fixedly installed to insert the brake cable into and out of the drum brake, and is fitted into the mounting hole provided in the backing plate from the inside of the backing plate,
A fitting portion having an insertion hole through which the brake cable is inserted is integrally provided so as to protrude from the fitting portion to the outer peripheral side, and is a peripheral portion of the mounting hole and contacts an inner surface of the backing plate. A cable guide for a drum brake, comprising: a flange portion that is brought into contact with the cable guide. 2. The brake cable is divided into a first cable on the drum brake side and a second cable on the pulling force applying side, the first cable being outside the backing plate without an outer casing. The cable guide for the drum brake according to claim 1, wherein the cable guide extends to the cable guide. 3. The brake cable is arranged substantially parallel to the backing plate inside the drum brake, and the direction of the brake cable is changed outward in the cable guide portion. The cable guide of the drum brake according to claim 1 or 2, wherein a load acting in an outward direction is applied when the brake cable is pulled.