JP3629295B2 - Drum-in disc brake shoe return spring - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a drum-in disc brake, and more particularly to a technique for preventing rattling of a brake lever and a strut in a drum brake portion with a simple configuration.
[0002]
[Prior art]
A drum-in disc brake in which a parking brake drum brake is incorporated inside a disc brake is known. The drum brake in this case includes (a) a pair of first brake shoes and a second brake shoe disposed on a backing plate. A brake shoe, (b) a brake lever attached to be rotatable about a pin substantially perpendicular to the backing plate side of the first brake shoe, and (c) a notch formed at least at one end to form the brake lever And struts straddling the brake lever and the second brake shoe, and the brake lever is rotated around the pin so that the strut is inserted through the strut. The first brake shoe and the second brake shoe are separated from each other and are shared with the wheel. The pressed against the cylindrical inner peripheral surface of the rotating body that rotates and is configured to generate the braking force is normal. The device described in Japanese Utility Model Laid-Open No. 5-66344 is an example.
[0003]
FIG. 5 is a view showing an example of a drum brake portion in such a conventional drum-in-disc brake. The backing plate 10 is provided with a pair of first brake shoes 12 and a second brake shoe 14. 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 in the drawing. A strut 20 is bridged between the brake lever 18 and the second brake shoe 14, the parking brake operation lever, the pedal, etc. are operated to pull the cable 22, and the brake lever 18 is rotated counterclockwise around the pin 16. When rotated, the second brake shoe 14 is pressed rightward together with the strut 20 and is 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 supported with the strut 20 as a fulcrum. Is pressed to the left and is also pressed to the inner peripheral surface of the cylindrical portion of the rotating body. Notches 19 and 21 are formed at both ends of the strut 20, and the brake lever 18 and the shoe web 14a of the second brake shoe 14 are engaged in the notches 19 and 21, respectively. In one notch 19, the shoe web 12 a of the first brake shoe 12 is also engaged together with the brake lever 18. Further, shoe return springs 26 and 28 are respectively stretched between the anchor member 24 fixed to the backing plate 10 and the first brake shoe 12 and the second brake shoe 14, and both brake shoes 12, 14 is returned to the inside.
[0004]
By the way, in such a drum-in-disc brake, in order to prevent the strut 20 and the brake lever 18 from rattling due to vibrations during traveling of the vehicle, the strut 20 is strutted by an anti-rattle spring 30. 20 is forcibly pressed against the shoe webs 12a, 14a. The notches 19 and 21 are set to have a large size so that the brake lever 18 and the shoe web 12a are not caught and the shoe web 14a is not caught. As for the brake lever 18, as shown in FIG. 6, a shim 34 having a predetermined thickness is interposed between the C washer 32 for mounting and the brake lever 18, and a gap between the brake lever 18 and the shoe web 12a. Is set to be substantially zero. A plurality of types of shims 34 having different plate thicknesses may be prepared and used according to the size of the gap.
[0005]
[Problems to be solved by the invention]
However, such a conventional rattling prevention method is to add a new part for that purpose, so that the number of parts is increased and the assembly is troublesome and the manufacturing cost is increased. Particularly, since it is necessary to use a plurality of types of shims depending on the gap, the assembling work is further troublesome.
[0006]
The present invention has been made against the background of the above circumstances, and its purpose is to prevent rattling of brake levers and struts with a simple configuration, reducing the number of parts and simplifying assembly work. And to provide the device at a low cost.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the present invention includes (a) a pair of first brake shoes and second brake shoes disposed on a backing plate, and (b) the first brake shoes substantially on the backing plate side. A brake lever rotatably attached around a vertical pin; and (c) a notch is formed at least at one end and engaged with the brake lever, straddling the brake lever and the second brake shoe. The first brake shoe and the second brake shoe are separated from each other through the strut and rotated together with the wheel. Drum-in-disc brake having a drum brake that is pressed against the inner peripheral surface of the cylindrical portion of the rotating body to generate a braking force A shoe return spring disposed across the anchor member fixed to the backing plate and the first brake shoe or the second brake shoe and returning the brake shoe to the inside when the brake is released, (D) a first locking portion locked to the brake shoe, (e) a second locking portion locked to the anchor member, and (f) the second locking portion and the first engagement. A tension coil portion provided between the locking portion and biasing the two to approach each other; and (g) extending from one of the first locking portion and the second locking portion and engaging with the strut. A third locking portion that is stopped and urges at least the one end side of the strut in a direction away from the backing plate.
[0008]
[Action]
That is, a third locking portion is provided on a shoe return spring that returns the brake shoe inward when the brake is released, and the third locking portion is locked to the strut, thereby engaging with at least one end side of the strut, that is, the brake lever. The end portion on the side to be joined is urged away from the backing plate, whereby the notch on the one end portion side of the strut is pressed and brought into close contact with the brake lever. The brake shoe is pressed and brought into close contact. Therefore, these struts and brake levers are integrally brought into close contact with the first brake shoe, and rattling caused by vibrations during traveling of the vehicle is prevented.
[0009]
On the other hand, in the present invention, since the shoe return spring is simply provided with the third locking portion and locked with the strut, the conventional anti-rattle spring and shim are not required, the number of parts is reduced, and the assembly work is facilitated. This can be done quickly and the manufacturing cost is reduced.
[0010]
【The invention's effect】
As described above, according to the shoe return spring of the present invention, rattling of struts and brake levers due to vibration during vehicle travel is prevented, while conventional anti-rattle springs and shims are not required. As the number of points is reduced, the assembling work can be performed easily and quickly, and the manufacturing cost is reduced.
[0011]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Parts that are substantially the same as those in the conventional example in FIG.
[0012]
In FIG. 1, the brake shoes 12 and 14 are supported so as to be able to expand each other while being pressed toward the backing plate 10 by shoe hold-down devices 52 and 54, respectively. One end of each of the brake shoes 12 and 14 is brought into contact with the side surface of the anchor member 24 according to the urging force of the pair of first shoe return spring 56 and second shoe return spring 58. , 14 are engaged with both ends of a connecting member 62 that adjusts the shoe clearance by being extended with the rotation of the adjusting wheel 60 by springs (not shown). A locking member 68 is integrally attached to the anchor member 24, and the shoe return springs 56 and 58 are latched to a pair of locking portions 70 and 72 of the locking member 68. The locking portions 70 and 72 are provided with notches, and the shoe return springs 56 and 58 are latched on the notches, whereby the height position and the posture around the coil center line are substantially positioned.
[0013]
The first shoe return spring 56 constitutes an embodiment of the present invention. The first shoe return spring 56 is locked to the shoe web 12a of the first brake shoe 12, and the lock is fixed to the anchor member 24. A second locking portion 76 that is latched to the locking portion 70 of the member 68, and a biasing force provided so as to bring them closer to each other provided between the first locking portion 74 and the second locking portion 76. And a third locking portion 80 extending from the second locking portion 76 and hooked to the strut 20. 3 and 4, the strut 20 has a long hole 82 elongated in the longitudinal direction, that is, in the left-right direction in FIG. 1, in other words, one end that is engaged with the brake lever 18. The third locking portion 80 is hooked in the elongated hole 82 so as to be movable in the longitudinal direction. In the 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, the third locking portion 80 is shown in FIG. As shown, it extends upward, i.e., away from the backing plate 10, and the third locking portion 80 is hooked in the elongated hole 82, so that the strut 20, particularly the first brake shoe 12 side, is separated from the backing plate 10. It is biased in the direction of separating.
[0014]
In FIG. 2 showing the II-II cross section of FIG. And a disk portion 46 that projects to the bottom, and a wheel is attached to the bottom wall 42 and rotated integrally. The disk portion 46 of the rotating body 40 is a portion corresponding to a brake disc of a disc brake, and is braked by a pair of brake pads being pressed from both sides by a caliper (not shown) disposed on the backing plate 10. A cylindrical portion 44 of the rotating body 40 is a portion corresponding to a brake drum of a drum brake, and is braked when the pair of brake shoes 12 and 14 are pressed against the inner peripheral surface. The backing plate 10 is fixed to the axle housing by a plurality of bolts 48, and a synthetic resin dust cover 50 is integrally attached to the outer periphery of the backing plate 10. In FIG. 2, the strut 20, the cable 22, the connecting member 62, and the like are omitted.
[0015]
In the drum-in disc brake configured as described above, a pair of pads provided on the caliper is pressed against the disc portion 46 of the rotating body 40 by a depression operation of a brake pedal or the like during normal traveling. When the vehicle is parked, the brake lever 18 is rotated counterclockwise by the cable 22 by the operation of the parking brake operation lever, pedal, etc., so that the shoe return spring 56, The brake shoes 12 and 14 are separated from each other against the urging force 58 and pressed against the inner peripheral surface of the cylindrical portion 44 of the rotating body 40 to generate a braking force. At the time of releasing the brake by the parking brake, 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 returned to positions where one end portions thereof are in 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 the parking brake, and the braking torque generated in the brake shoes 12, 14 is transmitted from either one of the brake shoes 12, 14 to the anchor member 24. Is done.
[0016]
Here, in the drum-in disc brake of the present embodiment, a third locking 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 locking portion. Since one end portion of the strut 20 to which 80 is latched is urged away from the backing plate 10, one end portion of the strut 20, that is, the notch 19 is pressed against the brake lever 18 to be brought into close contact therewith. The brake lever 18 is further pressed against the shoe web 12a of the first brake shoe 12 and brought into close contact therewith. Accordingly, the struts 20 and the brake lever 18 are integrally brought into close contact with the first brake shoe 12, and rattling caused by vibrations during traveling of the vehicle is prevented.
[0017]
In this way, in the present embodiment, the first shoe return spring 56 prevents rattling of the strut 20 and the brake lever 18 due to vibrations during traveling of the vehicle. It becomes unnecessary, the number of parts is reduced, the assembly work can be performed easily and quickly, and the manufacturing cost is reduced.
[0018]
As mentioned above, although one Example of this invention was described in detail based on drawing, this invention can also be implemented in another aspect.
[0019]
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 on both of them. Is also possible.
[0020]
In the above-described embodiment, the third locking portion 80 extends from the second locking portion 76, but it is also possible to provide a third locking portion on the first locking portion 74 side. In that case, a part of the shoe web 12a is bent up or a pin is erected to hold the first locking portion 74, and the third locking portion is moved from the upper side of the shoe web 12a in the same manner as in the above embodiment. Although it may be extended, it can be extended to the strut 20 side through the lower side of the shoe web 12a and the brake lever 18, that is, between the brake lever 18 and the backing plate 10.
[0021]
In the above-described embodiment, the third locking portion 80 is locked to one end portion of the strut 20, that is, the notch 19 side. However, if at least the notch 19 side can be urged away from the backing plate 10. Also, it may be locked to other parts such as the central part of the strut 20.
[0022]
In the 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. May be.
[0023]
Further, the drum-in-disc brake of the above embodiment is configured to have a duo-servo type drum brake, but it may have other types of drum brakes.
[0024]
Although not exemplified one by one, the present invention can be carried out in various modifications and improvements based on the knowledge of those skilled in the art.
[Brief description of the drawings]
FIG. 1 is a view showing a drum brake portion of an example of a drum-in-disc brake having a shoe return spring according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
3 is a view showing a state in which a third locking portion of a shoe return spring and a strut are locked in the embodiment of FIG. 1; FIG.
4 is a view of FIG. 3 as viewed from the right.
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 shown in 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 portion 80: Third locking portion

Claims (1)

A pair of first brake shoes and second brake shoes disposed on the backing plate, a brake lever rotatably mounted around a pin substantially perpendicular to the backing plate side of the first brake shoes, and at least one end A notch is formed in the portion and engaged with the brake lever, and includes a strut disposed across the brake lever and the second brake shoe, and the brake lever rotates about the pin The first brake shoe and the second brake shoe are separated from each other via the strut, and the drum brake is pressed against the inner peripheral surface of the cylindrical portion of the rotating body that rotates together with the wheel to generate a braking force. In the drum-in disc brake, an anchor member fixed to the backing plate; Serial disposed me first extend over the brake shoe or second brake shoe, a shoe return spring when releasing the brake return the brake shoe to the inside,
A first locking portion locked to the brake shoe;
A second locking portion locked to the anchor member;
A tension coil portion provided between the second locking portion and the first locking portion and energizing the two locking portions to approach each other;
A third extending from either one of the first locking portion and the second locking portion to be locked by the strut and biasing at least the one end side of the strut in a direction away from the backing plate. A shoe return spring for a drum-in-disc brake, characterized by having a locking portion.

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