JP2001317570A - Drum brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum brake device preventing the generation of abnormal sound due to a collision between a brake shoe end portion and an anchor member when releasing braking. SOLUTION: In this floating shoe type drum brake device 29, when brake operating force is released, both brake shoes come off from a drum inner peripheral surface by energizing force of a shoe-to-shoe spring 39, and the other end portion of either one of the brake shoes separating from an anchor member 37 is returned to a state abutting on the anchor member 37. A leaf spring 45 is attached to the anchor member 37, which is interposed between shoe abutting portions 37a, 37b of the anchor member 37 on which the other end portion of the brake shoe is abutted and the other end portion of the brake shoe so as to absorb the shock of a collision between the brake shoe and the anchor member 37 when brake operating is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum brake device in which an end of a brake shoe separated from an anchor member at the time of braking returns to a state of contact with the anchor member by release of a brake operating force. The present invention relates to an improvement for preventing generation of abnormal noise due to a collision between an end of a brake shoe and an anchor member.

[0002]

2. Description of the Related Art FIGS. 13 and 14 show a conventional example of a drum brake device additionally provided with a leaf spring to prevent generation of abnormal noise due to collision between an end of a brake shoe and an anchor member when braking is released. Things.

[0003] This drum brake device 1 is disclosed in Utility Model Registration No. 2573326, and includes a pair of brake shoes 3, 4 of a primary shoe 3 and a secondary shoe 4, which are arranged to face each other on the inner periphery of the drum. A backing plate 6 that supports the brake shoes 3 and 4 so as to be able to expand toward the inner periphery of the drum, and one of the opposite ends of the pair of brake shoes 3 and 4 are connected to each other. An adjuster unit 8 for adjusting the interval between the brake shoes 3 and 4 and a backing plate 6 so as to be located between the other opposed ends of the pair of brake shoes 3 and 4.
And a pair of brakes such that the other ends of the pair of brake shoes 3 and 4 are in contact with the anchor member 11 during non-braking. A shoe return spring 13 for urging the shoes 3 and 4 toward each other;
And a strut 16 as a shoe drive mechanism that is disposed between the other opposed ends of the pair of brake shoes 3 and 4 and expands the other ends of the brake shoes 3 and 4 according to the brake operating force. Configuration.

The above-described drum brake device 1 is a so-called duo-servo type drum brake device, and the drum rotates in the direction of the arrow (A) when moving forward. At the time of forward braking, as shown in FIG. 14, the primary shoe 3 is pressed against the inner peripheral surface of the drum while the other end is separated from the anchor member 11 (indicated by a distance L in FIG. 14). The secondary shoe 4 is pressed against the inner peripheral surface of the drum while the other end of the secondary shoe 4 is in contact with the anchor member 11, and a braking torque is transmitted from the other end of the secondary shoe 4 to the anchor member 11, and The braking performance of is exhibited.

[0005] When the brake operating force is released,
With the urging forces of the shoe springs 13 and 14, both the brake shoes 3 and 4 are separated from the inner peripheral surface of the drum, and the other end of the primary shoe 3 separated from the anchor member 11 is in contact with the anchor member 11. Returned to state. At this time, the brake shoes return to the shoe spring 1
The collision speed of the primary shoe 3 against the anchor member 11 is considerable because it is performed instantaneously according to the urging forces of 3, 14. Therefore, in order to prevent generation of abnormal noise due to the collision at this time, in the example shown here, the webs 3a and 4a of the brake shoes 3 and 4 are provided with the leaf springs 17 for buffering the collision with the anchor member 11. Have been.

[0006]

In the drum brake device, the webs 3a, 3b of the brake shoes 3, 4 are provided.
A space 18 between the backing plate 4a and the backing plate 6 is a space where various components such as a parking lever 19 and cables 20 for transmitting the brake operating force to the lever 19 are arranged. However, as described above, in the configuration in which the leaf springs 17 for cushioning are provided on the webs 3a and 4a,
Since the leaf spring 17 moves together with the brake shoes 3 and 4 in the space 18 when the brake shoes 3 and 4 expand, the substantial occupied space of the leaf spring 17 in the space 18 is However, there is a problem that the arrangement of components such as the lever 19 and the cable 20 becomes difficult.

Further, since the leaf spring 17 is attached to the brake shoes 3 and 4 which are movable parts, there is a possibility that an external load such as vibration during traveling of the vehicle is amplified and acts on the leaf spring 17. In some cases, there is a risk of inconvenience such as falling off or a reduction in life due to fatigue or the like. In order to prevent such a situation from occurring, the leaf spring 17 itself and the leaf spring 1 are required.
There is a problem that the strength of the fixing structure of No. 7 needs to be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to a drum brake device for preventing generation of abnormal noise due to a collision between a brake shoe and an anchor member at the time of release of braking by a cushioning leaf spring. The space occupied by the cushioning leaf spring in the space between the plate and the plate can be reduced to facilitate the arrangement of other components in the space between the brake shoe and the backing plate, and It is an object of the present invention to provide a drum brake device capable of avoiding amplifying and acting on an external load such as vibration during traveling of a vehicle and reducing the strength of the leaf spring itself and its fixing structure and improving the life. And

[0009]

According to the present invention, there is provided a drum brake device according to the present invention, wherein a primary shoe is disposed opposite to an inner periphery of a drum, and one of the opposite ends is connected via an adjuster unit. A pair of brake shoes of a secondary shoe, a backing plate for supporting the brake shoes so as to be able to expand toward the inner periphery of the drum, and the backing plate so as to be located between the other opposed ends of the pair of brake shoes. And an anchor member, which is spring-biased in a direction in which the other ends of the brake shoes approach each other and is in contact with each other, and which is disposed between the other opposite ends of the pair of brake shoes and A shoe drive mechanism that expands the other end of the pair of brake shoes against the spring urging force. A state in which the shoe is pressed against the drum inner peripheral surface with the other end separated from the anchor member, and the other brake shoe is pressed against the drum inner peripheral surface with the other end contacting the anchor member. When the braking torque is transmitted from the other end of the other brake shoe to the anchor member and the brake operating force is released, both brake shoes are separated from the drum inner peripheral surface by the spring urging force, and the anchor In a floating shoe type drum brake device in which the other end of one of the brake shoes separated from the member is brought back into contact with the anchor member, the other end of the brake shoe separated from the anchor member during braking is provided. The other end of the brake shoe is interposed between the shoe contact portion of the anchor member and the brake shoe and the anchor portion when the brake operation is released. The leaf spring to buffer the collision between, characterized in that attached to the anchor member.

According to the above construction, the buffer leaf spring is provided on the anchor member, which is a fixed structure on the backing plate, and does not move in conjunction with the expanding operation of each brake shoe. Therefore, the substantial space occupied by the cushioning leaf spring in the space between the brake shoe and the backing plate can be reduced to substantially the actual size of the leaf spring, and the space occupied by the leaf spring is minimized. The arrangement of other components in the space between the brake shoe and the backing plate can be facilitated. In addition, since the cushioning leaf spring is provided on the anchor member which is a fixed structure on the backing plate, compared with the conventional case equipped on the brake shoe,
External loads such as vibrations during the running of the vehicle can be prevented from being amplified and acting, and the anti-vibration strength etc. can be set low, and eventually the strength of the leaf spring itself and its fixed structure is suppressed. However, the life can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a drum brake device according to the present invention will be described below in detail with reference to the drawings. 1 to 8 show a first embodiment of a drum brake device according to the present invention. FIG. 1 is a front view of a drum-in-disk brake device to which the present invention is applied, and FIG. FIG. 3 is an enlarged front view of a main part of the drum brake device shown in FIG. 1, FIG. 4 is a view taken in the direction of the arrow IV in FIG. 3, and FIG. 5 is a view taken in the direction of the arrow V in FIG. 6 is a plan view of the anchor member shown in FIG. 3, FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6, and FIG. 8 is a view of arrow VIII of FIG.

As shown in FIGS. 1 and 2, the drum-in-disc brake device 21 shown in FIG. 1 has a cylindrical drum 23a having a bottom and a flange formed radially outward from an opening edge of the drum 23a. A rotating member 23 integrally provided with a protruding rotor 23b and attached to a wheel side; and a primary shoe attached to a vehicle body (not shown) so as to cover an opening of the drum 23a and pressing an inner peripheral surface of the drum 23a. And a backing plate 28 for supporting a pair of brake shoes 25 and 26 (see FIG. 3) of the secondary shoe 26 and the secondary shoe 26. In addition to the braking by the disk brake device acting on the rotor 23b, the present invention acts on the drum 23a. This enables braking by the drum brake device 29.

As shown in the figure, the backing plate 28 includes a backing plate main body 30 which is an integrally formed product of a metal plate, and an auxiliary plate 31 which is integrated with the outer surface of the backing plate main body 30 by welding. . The backing plate main body 30 is in the shape of a circular dish that covers the opening of the drum 23a. Further, the auxiliary plate 31 projects radially outward of the backing plate main body 30 to cover the surface of the rotor 23b, and functions as a dust cover. As shown in FIG. 1, the auxiliary plate 31 is formed with a notch 31a serving as a mounting space for a caliper constituting the disc brake device.

In the drum-in disc brake device 21, the disc brake device including the rotor 23b as a component is operated as a service brake.
The drum brake device 29 of the present invention including the drum 23a as a component is operated as a parking brake.

The drum brake device 29 is a so-called floating shoe type drum brake device, and as shown in FIG. 3, a pair of brake shoes 25 of a primary shoe 25 and a secondary shoe 26 which are arranged opposite to the inner periphery of the drum 23a. 26 and a pair of these brake shoes 2
A backing plate 28, which is supported by a shoe hold-down pin 33 penetrating through the webs 25a, 26a so as to be able to expand toward the inner periphery of the drum 23a, and one facing end of each of the brake shoes 25, 26 are connected to each other. And an adjuster unit 35 for adjusting the distance between these brake shoes in accordance with wear and
The brake shoes 2 are fixed to the backing plate 28 so as to be located between the other opposed ends of the brake shoes 2 and 26 during braking.
An anchor member 37 receiving a braking torque from the pair of brake shoes 25 and 26 and a pair of brake shoes 25 and 26 such that the other ends of the pair of brake shoes 25 and 26 are in contact with the shoe contact portions 37a and 37b of the anchor member 37 when braking is not performed. A shoe-to-shoe spring 39 and an adjuster spring 41 for urging the brake shoes 25 and 26 in a direction approaching each other, and a brake operating force at the time of parking brake operation, which is disposed between the other opposing ends of the pair of brake shoes 25 and 26. And a shoe driving mechanism 43 for expanding the other ends of the pair of brake shoes 25 and 26 in accordance with the above, and interposed between the other end of the primary shoe 25 and the shoe contact portion 37 a of the anchor member 37. And a leaf spring 45 for buffering a collision between the end of the primary shoe 25 and the anchor member 37 when the brake operation is released. That.

As shown in FIGS. 6 to 8, the anchor member 37 includes a base block 50 provided with insertion holes 50a for anchor fixing bolts 47, which are fastening means to the backing plate 28, at both ends thereof. An anchor block 51 is provided integrally with an upright portion 50 and both side surfaces are shoe contact portions 37a and 37b. The anchor block 51 is fastened and fixed to the backing plate 28 by two anchor fixing bolts 47.

In the case of the present embodiment, the leaf spring 45 is used.
Is, as shown in FIG. 4 and FIG.
A spring portion 45a interposed between the anchor member 37 and the shoe contact portion 37a, and a screw portion 45b fixed to the base block portion 50 by the anchor fixing bolt 47 are integrally formed of a metal plate having excellent spring properties. It is attached to the base block 50 of the anchor member 37 by the anchor fixing bolt 47. The spring portion 45a is shown in FIG.
As shown in the figure, the end of the primary shoe 25 is expanded by a distance s from the shoe contact portion 37a of the anchor member 37 during braking.
When the primary shoe 25 is separated from the primary shoe 25 by a predetermined angle of inclination so that the lower end abuts on the shoe abutting portion 37a of the anchor member 37 and the tip abuts on the end surface of the primary shoe 25. During operation, the impact at the time of collision between the primary shoe 25 and the anchor member 37 is reduced by elastic deformation in the direction in which the inclination angle θ decreases.

In the above-described drum brake device 29,
During forward running of the vehicle, the drum 23a rotates in the direction of the arrow (a) in FIG. When the parking brake operation is performed after the vehicle is stopped by the operation of the service brake, the pair of brake shoes 25 and 26 are expanded by the shoe driving mechanism 43, and the primary shoe 2 is opened.
5 is pressed against the inner peripheral surface of the drum 23a with the other end separated from the anchor member 37, and the other secondary shoe 26 is pressed against the inner peripheral surface of the drum 23a with the other end contacting the anchor member 37. In the pressed state, the braking torque is transmitted from the other end of the secondary shoe 26 to the anchor member 37, and a predetermined braking force is exerted. When the brake operation force is released by the release operation of the parking brake lever, both the brake shoes 25 and 26 are driven by the urging force of the shoe-to-shoe spring 39 so that the two drums 2 and 5 are driven.
3a is separated from the inner peripheral surface, and the other end of the primary shoe 25 separated from the anchor member 37 is returned to a state of being in contact with the anchor member 37. At this time, the end of the primary shoe 25 and the anchor are separated. The impact is buffered by the leaf spring 45 interposed between the member 37 and the generation of abnormal noise.

According to the above construction, the leaf spring 45 for buffering is used.
Are mounted on an anchor member 37 which is a fixed structure on the backing plate 28, and each brake shoe 25,
Since it does not move in conjunction with the expanding operation of the spring 26, the substantial occupied space of the cushioning leaf spring 45 in the space between the brake shoes 25, 26 and the backing plate main body 30 is substantially the same as that of the leaf spring 45. The size can be reduced to a minimum, and the space occupied by the leaf spring 45 is minimized, so that the arrangement of other components in the space between the brake shoe and the backing plate 28 can be facilitated. Further, since the cushioning leaf spring 45 is provided on the anchor member 37 which is a fixed structure on the backing plate 28, the vibration during traveling of the vehicle is lower than that of the conventional case provided on the brake shoe. It is possible to prevent the external load such as from being amplified and acting, and to set the vibration-proof strength and the like low. As a result, even if the strength of the leaf spring 45 itself and its fixing structure is suppressed, the life is shortened. Can be improved.

The drum brake device to which the present invention is applied is not limited to the drum brake operated as the parking brake described above. It is also applicable to a duo-servo type drum brake operated as a service brake. Further, for example, when a state in which the braking is released from the reverse braking state and the secondary shoe comes into contact with the anchor member from a state in which the secondary shoe is separated from the anchor member can occur, the leaf spring is used for the primary shoe and the secondary shoe. It is also conceivable that the anchor members are individually provided.

FIGS. 9 to 12 show a second embodiment of the drum brake device according to the present invention. The drum brake device 55 according to the second embodiment includes a first
Instead of the leaf spring 45 in the embodiment, the leaf spring 5
The configuration other than the leaf spring 57 is common to the drum brake device 29 of the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIGS. 10 to 12, the leaf spring 57 of the second embodiment includes a spring portion 57a interposed between the primary shoe 25 and the shoe contact portion 37a of the anchor member 37, and an anchor fixing bolt. 47 is formed integrally with a screw fitting portion 57b fitted and fixed to the head portion of a metal plate having excellent spring properties.
b is fixed to the anchor member 37 by fitting it to the head of the anchor fixing bolt 47. Spring part 57a
As shown in FIG. 10, the end of the primary shoe 25 is expanded at the time of braking and the shoe contact portion 37a of the anchor member 37 is opened.
When a predetermined angle of inclination θ is given so that the lower end contacts the shoe contact portion 37a of the anchor member 37 and the front end contacts the end surface of the primary shoe 25 when the primary shoe 25 is separated from the primary shoe 25 by a distance s. At the time of the return operation of 25, the impact at the time of collision between the primary shoe 25 and the anchor member 37 is reduced by elastic deformation in the direction in which the inclination angle θ decreases.

When such a leaf spring 57 is employed, the work of attaching the leaf spring 57 is facilitated, and in addition to the operation and effect described in the first embodiment, shortening of the assembling work time can be achieved. it can.

[0023]

According to the drum brake device of the present invention,
The cushioning leaf spring is provided on an anchor member, which is a fixed structure on the backing plate, and does not move in conjunction with the expanding operation of each brake shoe. The substantial space occupied by the cushioning leaf spring in the space can be reduced to substantially the actual size of the leaf spring, and the space occupied by the leaf spring is minimized, resulting in the space between the brake shoe and the backing plate. Can be easily arranged. In addition, since the cushioning leaf spring is provided on the anchor member, which is a fixed structure on the backing plate, compared with the conventional case equipped with the brake shoe, the vibration of the vehicle during running is reduced. It is possible to prevent the mechanical load from being amplified and acting, and to set the vibration resistance and the like to be low. As a result, even if the strength of the leaf spring itself and its fixing structure is suppressed, the life can be improved. it can.

[Brief description of the drawings]

FIG. 1 is a front view of a drum-in-disk brake device to which a drum brake device according to the present invention is applied.

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

FIG. 3 is an enlarged front view of a main part of the drum brake device shown in FIG.

FIG. 4 is a view taken in the direction of the arrow IV in FIG. 3;

FIG. 5 is a view taken in the direction of the arrow V in FIG. 3;

FIG. 6 is a plan view of the anchor member shown in FIG. 3;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a view taken in the direction of the arrow VIII in FIG. 6;

FIG. 9 is an enlarged plan view of a main part of a second embodiment of the drum brake device according to the present invention.

10 is a view as viewed in the direction of the arrow X in FIG. 9;

11 is a view as viewed in the direction of the arrow XI in FIG. 9;

FIG. 12 is a view on arrow XII of FIG. 9;

FIG. 13 is a front view of a conventional drum brake device for preventing generation of abnormal noise by a buffer leaf spring.

14 is a sectional view taken along the line XIV-XIV in FIG.

[Explanation of symbols]

 Reference Signs List 21 drum-in-disc brake device 23 rotating member 23a drum 23b rotor 25 primary shoe (brake shoe) 26 secondary shoe (brake shoe) 28 backing plate 30 backing plate body 31 auxiliary plate 33 shoe hold-down pin 35 adjuster unit 37 anchor member 37a, 37b Shoe contact portion 39 Shoe-to-shoe spring 45 Leaf spring 45a Spring portion 45b Screwed portion 47 Anchor fixing bolt 55 Drum brake device 57 Leaf spring 57a Spring portion 57b Screw fitting portion

Claims (1)

[Claims] 1. A pair of primary and secondary shoes, which are disposed opposite to the inner periphery of a drum and whose opposite ends are connected to each other via an adjuster unit, and the brake shoes are directed toward the inner periphery of the drum. A backing plate which is supported so as to be expandable and is fixed to the backing plate so as to be located between the other opposing ends of the pair of brake shoes, and a spring bias is applied in a direction in which the other ends of the brake shoes approach each other. And a shoe arranged between the other end of the pair of brake shoes and the other end of the pair of brake shoes that opens in opposition to a spring urging force in response to a brake operating force. A driving mechanism, and when braking, when one brake shoe is pressed against the inner peripheral surface of the drum while the other end is separated from the anchor member. In both cases, the other brake shoe is pressed against the drum inner peripheral surface with the other end abutting on the anchor member, and the braking torque is transmitted from the other end of the other brake shoe to the anchor member, When the brake operation force is released, both brake shoes are separated from the inner peripheral surface of the drum by the spring biasing force, and the other end of one of the brake shoes separated from the anchor member is in contact with the anchor member. In the floating shoe type drum brake device returned to the state, the other end of the brake shoe separated from the anchor member during braking and the shoe contact portion of the anchor member contacted by the other end of the brake shoe A leaf spring for buffering a collision between the brake shoe and the anchor member when the brake operation is released is attached to the anchor member. Brake device.