JPH08284988A - Shoe return spring of drum-in disk brake - Google Patents

Abstract

PURPOSE: To provide a shoe return spring where the play of a brake lever or a strut which are parts of a drum brake is prevented by a simple constitution, the number of parts is reduced, the assembling work is simplified, and the device is inexpensive. CONSTITUTION: A third locking part 80 to energize a strut 20 in the direction separating from a backing plate 10 is extended to a first shoe return spring 56 which is stretched between a first brake shoe 12 and an anchor member 24, and returns the first brake shoe 12 inwardly when the brake is released, and a notch 19, a brake lever 18, and a shoe web 12a of the first brake shoe 12 are closely attached to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum-in disc brake, and more particularly to a technique for preventing rattling of a brake lever or strut in a drum brake portion with a simple structure.

[0002]

2. Description of the Related Art There is known a drum-in disc brake in which a drum brake for a parking brake is incorporated in the disc brake. In this case, the drum brake is (a) a pair of first disc brake plates. A brake shoe and a second brake shoe, (b)
A brake lever rotatably mounted around a pin substantially perpendicular to the backing plate side of the first brake shoe, and (c) a notch is formed in at least one end to be engaged with the brake lever, A first strut disposed between the first brake shoe and the second brake shoe, the strut being disposed over the brake lever and the second brake shoe; It is usual that the two brake shoes are separated from each other and are pressed against the inner peripheral surface of the cylindrical portion of the rotating body that rotates with the wheel to generate a braking force. The device described in Japanese Utility Model Laid-Open No. 5-66344 is an example.

FIG. 5 is a view showing an example of a drum brake portion in such a conventional drum-in disc brake, in which a backing plate 10 is provided with a pair of first brake shoes 12 and second brake shoes 14. In addition, a brake lever 18 is attached to the back side of the first brake shoe 12, that is, the backing plate 10 side so as to be rotatable around a substantially vertical pin 16 at one end portion on the upper side of the drawing. Struts 20 are laid between the brake lever 18 and the second brake shoe 14, and the cable 22 is pulled by operating the parking brake operating lever, pedals, etc., and the brake lever 18 is rotated counterclockwise to the pin 16. When rotated,
The second brake shoe 14 is pressed rightward together with the strut 20 to be pressed against the inner peripheral surface of the cylindrical portion of the rotating body (not shown), and the pin 16 and the first brake shoe 12 are pressed leftward with the strut 20 as a fulcrum. Similarly, it is pressed against the inner peripheral surface of the cylindrical portion of the rotating body. Strut 20
Notches 19 and 21 are formed at both ends of the
The brake lever 18 and the shoe web 14a of the second brake shoe 14 are engaged in the insides of 9 and 21, respectively. The shoe web 12 a of the first brake shoe 12 is engaged with the brake lever 18 in the notch 19. Further, shoe return springs 26 and 28 are stretched between the anchor member 24 fixed to the backing plate 10 and the first brake shoe 12 and the second brake shoe 14, respectively, and both brake shoes 12 and 28 are released when the brake is released. It is designed to return 14 to the inside.

By the way, in such a drum-in disc brake, in order to prevent the strut 20 and the brake lever 18 from rattling and making an abnormal noise due to vibrations during traveling of the vehicle, the strut 20 has an anti-rattle spring. The strut 20 is forcibly pressed against the shoe webs 12a, 14a side by means of 30. The notches 19 and 21 are provided in the brake lever 18
The shoe web 12a and the shoe web 14a are set to have a large size so as not to be caught. As for the brake lever 18, as shown in FIG. 6, a C washer 32 for mounting is used.
A shim 34 having a predetermined thickness is inserted between the brake lever 18 and the brake lever 18 so that the gap between the brake lever 18 and the shoe web 12a becomes substantially zero. As the shim 34, a plurality of kinds having different plate thicknesses may be prepared and used properly according to the size of the gap.

[0005]

However, since such a conventional rattling prevention method adds a new component for that purpose, the number of the components is increased and the assembly is troublesome and the manufacturing is difficult. High cost. In particular,
As for the shims, it is necessary to use different types of shims depending on the gap, which makes the assembling work more troublesome.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent rattling of a brake lever or a strut with a simple structure, reduce the number of parts, and perform an assembling work. The purpose is to provide a device at low cost by simplifying the above.

[0007]

In order to achieve the above object, the present invention provides: (a) a pair of first brake shoes and second brake shoes arranged on a backing plate; and (b) the first brake shoes. A brake lever rotatably mounted around a pin substantially perpendicular to the backing plate side of the brake shoe, and (c) a notch is formed in at least one end to engage the brake lever, and the brake lever The second brake shoe and a strut arranged so as to straddle the second brake shoe, and the brake lever is rotated around the pin so that the first brake shoe and the second brake shoe are passed through the strut. Are separated from each other and have a drum brake that generates a braking force by being pressed against the inner peripheral surface of the cylindrical portion of the rotating body that rotates with the wheels. In a drum-in disc brake, a shoe return that is disposed across an anchor member fixed to the backing plate and the first brake shoe or the second brake shoe, and returns the brake shoe to the inside when releasing the brake. A spring,
(D) a first locking portion that is locked to the brake shoe,
(E) a second locking portion that is locked to the anchor member,
(F) a tension coil portion that is provided between the second locking portion and the first locking portion and urges them so that they approach each other;
(G) Extends from either one of the first locking portion and the second locking portion and is locked by the strut, and urges at least the one end side of the strut in a direction away from the backing plate. And a third locking portion.

[0008]

That is, the shoe return spring that returns the brake shoe to the inside when the brake is released is provided with the third locking portion, and the third locking portion is locked to the strut, so that at least one end side of the strut, that is, the brake. The end portion on the side to be engaged with the lever is urged in the direction away from the backing plate,
As a result, the notch on the one end side of the strut is pressed by the brake lever and brought into close contact therewith, and the brake lever is further pressed by the first brake shoe and brought into close contact therewith. Therefore, the struts and the brake levers are brought into close contact with the first brake shoe integrally, and rattling due to vibration during traveling of the vehicle is prevented.

On the other hand, according to the present invention, since the shoe return spring is only provided with the third engaging portion and is engaged with the strut, the conventional anti-rattle spring and shim are unnecessary, the number of parts is reduced and the assembling work is reduced. Can be performed easily and quickly, and the manufacturing cost can be reduced.

[0010]

As described above, according to the shoe return spring of the present invention, the rattling of the strut and the brake lever due to the vibration during traveling of the vehicle is prevented, while the conventional anti-rattle spring and the shim are unnecessary. Therefore,
The number of parts is reduced, the assembling work can be performed easily and quickly, and the manufacturing cost is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In addition, the portions substantially common to the conventional example of FIG. 6 are denoted by the same reference numerals and detailed description thereof will be omitted.

In FIG. 1, the brake shoes 12,
14 are supported by the shoe hold down devices 52 and 54 so as to be able to open each other while being pressed toward the backing plate 10. Further, one end of each of the brake shoes 12, 14 has a pair of a first shoe return spring 56 and a second shoe return spring 5
It is adapted to be brought into contact with the side surface of the anchor member 24 according to the urging force of 8, and the other ends of the brake shoes 12 and 14 are extended with the rotation of the adjust wheel 60 to adjust the shoe gap. Connecting member 62
Springs (not shown) are engaged with both ends of the. A locking member 68 is integrally attached to the anchor member 24, and a pair of locking portions 70, 7 of the locking member 68 are attached.
The shoe return springs 56 and 58 can be hooked on the second shaft. Notches are provided in the locking portions 70, 72, and shoe return springs 56, 5 are provided in the notches.
When 8 is hooked, the height position and the posture around the coil center line are substantially positioned.

The first shoe return spring 56, which constitutes an embodiment of the present invention, is fixed to the anchor member 24 and the first engaging portion 74 which is engaged with the shoe web 12a of the first brake shoe 12. The second locking portions 76 hooked to the locking portions 70 of the locking members 68 and the first locking portions 74 and the second locking portions 76 are provided so as to bring them close to each other. The tension coil portion 78 that urges the second locking portion 7
The third that extends from 6 and is hooked to the strut 20
And a locking portion 80. The strut 20 is shown in FIG.
And as clearly shown in FIG. 4, the long hole 82 which is long in the longitudinal direction, that is, the left-right direction in FIG.
It is formed on the 9 side, in other words, on the one end side that is engaged with the brake lever 18, and the third locking portion 80 is hooked in the elongated hole 82 so as to be relatively movable in the longitudinal direction. Further, the third locking portion 80 is in a state where the first locking portion 74 and the second locking portion 76 are hooked on the shoe web 12a and the locking portion 70, respectively, and in a natural state, is indicated by a chain line in FIG. As shown, it extends upward, that is, in a direction away from the backing plate 10, and by locking the third locking portion 80 in the elongated hole 82,
The strut 20 is urged particularly toward the first brake shoe 12 in a direction away from the backing plate 10.

In FIG. 2 showing the II-II cross section of FIG. 1, a rotary body 40 shown by a chain line is a cylindrical portion 44 having a bottom wall 42, and a cylindrical end portion 44 of the cylindrical portion 44 on the opening side. A disc portion 46 that projects from the outer peripheral side to the outer peripheral side is integrally provided, and a wheel is attached to the bottom wall 42 and integrally rotated. The disc portion 46 of the rotating body 40 is a portion corresponding to a brake disc of a disc brake, and is braked by pressing a pair of brake pads from both sides by a caliper (not shown) arranged on the backing plate 10, while The cylindrical portion 44 of the rotating body 40 corresponds to a brake drum of a drum brake, and is braked by pressing the pair of brake shoes 12 and 14 against the inner peripheral surface. The backing plate 10 includes a plurality of bolts 4
8 is fixed to the axle housing, and a synthetic resin dust cover 50 is integrally attached to the outer periphery of the backing plate 10. In FIG. 2, the struts 20, the cables 22, the connecting members 62 and the like are omitted.

In the drum-in disc brake having the above-described structure, a pair of pads provided on the caliper when the vehicle is normally traveling is provided with the disc portion 46 of the rotary member 40 by depressing the brake pedal. When the vehicle is parked, the brake lever 18 is moved by the cable 22 by the operation of the parking brake operating lever, pedal, etc.
By rotating the shoe 6 counterclockwise, the brake shoes 12 and 14 are separated from each other against the urging force of the shoe return springs 56 and 58, and pressed against the inner peripheral surface of the cylindrical portion 44 of the rotating body 40. Generates braking force. When the braking by the parking brake is released, the brake shoes 12 and 14 are brought close to each other according to the urging force of the shoe return springs 56 and 58, and the one ends of the brake shoes 12 and 14 are returned to the positions where they come into contact with the anchor member 24.
The drum-in disc brake of this embodiment is provided with a duo-servo type drum brake dedicated to a parking brake, and the braking torque generated in the brake shoes 12 and 14 is transmitted to the anchor member 24 from either one of the brake shoes 12 and 14. To be done.

Here, in the drum-in disc brake of this embodiment, the third engaging portion 80 is provided on the first shoe return spring 56 that returns the first brake shoe 12 to the inside when the parking brake is released, and the third engaging portion 80 is provided. Since the strut 20 to which the locking portion 80 is hooked is biased particularly toward the back end of the backing plate 10, one end of the strut 20, that is, the notch 19 is pressed by the brake lever 18. The brake lever 18 is further pressed against the shoe web 12a of the first brake shoe 12 to be brought into close contact therewith. Therefore, the struts 20 and the brake levers 18 are brought into close contact with the first brake shoe 12 integrally, and rattling due to vibration during traveling of the vehicle is prevented.

As described above, in the present embodiment, the first shoe return spring 56 prevents the rattling of the strut 20 and the brake lever 18 due to the vibration during traveling of the vehicle. The shim 34 is unnecessary, the number of parts is reduced, and the assembling work can be performed easily and quickly, and the manufacturing cost is reduced.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above embodiment, the third locking portion 80 for urging the strut 20 is provided on the first shoe return spring 56, but it may be provided on the second shoe return spring 58, or both of them. It is also possible to provide.

Further, in the above embodiment, the third locking portion 80 extends from the second locking portion 76, but it is possible to provide the third locking portion on the first locking portion 74 side. In that case,
By bending and raising a part of the shoe web 12a or erecting a pin, the first locking portion 74 is locked, and the third locking portion is extended from the upper side of the shoe web 12a in the same manner as in the above embodiment. Alternatively, the shoe web 12a and the brake lever 18 may be extended to the strut 20 side below the brake lever 18, that is, between the brake lever 18 and the backing plate 10.

Further, in the above-described embodiment, the third locking portion 80 is locked to one end of the strut 20, that is, the notch 19 side, but at least the notch 19 side is separated from the backing plate 10. If you can urge,
The strut 20 may be locked to other parts such as the central part of the strut 20.

Further, in the above embodiment, the shoe web 12a of the first brake shoe 12 is inserted into the notch 19 together with the brake lever 18, but only the brake lever 18 is inserted into the notch 19. It may be.

Further, although the drum-in disc brake of the above-mentioned embodiment is constructed to have a duo-servo type drum brake, it may be a type having other types of drum brakes.

Although not specifically exemplified, the present invention can be carried out in variously modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a drum brake portion of an example of a drum-in disc brake including a shoe return spring that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 with a part thereof omitted.

FIG. 3 is a diagram showing a locked state between a strut and a third locking portion of the shoe return spring in the embodiment of FIG.

FIG. 4 is a diagram of FIG. 3 viewed from the right side.

FIG. 5 is a diagram showing a drum brake portion of a conventional drum-in disc brake.

6 is a cross-sectional view showing a connecting portion between a brake shoe and a brake lever in the drum-in disc brake of FIG.

[Explanation of symbols]

 10: backing plate 12: first brake shoe 14: second brake shoe 16: pin 18: brake lever 19: notch 20: strut 56: first shoe return spring 74: first locking portion 76: second locking portion 78: Tensile coil part 80: Third locking part

Claims (1)

[Claims] 1. A pair of a first brake shoe and a second brake shoe arranged on a backing plate, and a brake rotatably mounted on a pin of the first brake shoe on a side substantially perpendicular to the backing plate. A lever and a strut having a notch formed in at least one end to be engaged with the brake lever, and the strut arranged across the brake lever and the second brake shoe. The first pin is moved through the strut by being rotated around the pin.
In the drum-in disc brake, the brake shoe and the second brake shoe are separated from each other and are pressed against the inner peripheral surface of the cylindrical portion of the rotating body that rotates with the wheel to generate a braking force, and fixed to the backing plate. A shoe return spring disposed across the anchor member and the first brake shoe or the second brake shoe and returning the brake shoe to the inside when the brake is released. One locking portion, a second locking portion locked to the anchor member, and provided between the second locking portion and the first locking portion and urges them to approach each other. A tension coil portion and one of the first locking portion and the second locking portion, which extends from one of the first locking portion and the second locking portion and is locked to the strut, A shoe return spring for a drum-in disc brake, comprising a third locking portion for urging the one end side in a direction away from the backing plate.