JPH08261259A - Shoe hold device of internal expanding type vehicular drum brake - Google Patents

Abstract

PURPOSE: To elastically hold a brake shoe by a simple structure in a single operation surely, eliminating the measures against waterproof and dustproof for the inside of a back plate and also stabilize the spring force of a shoe hold spring for the brake shoe. CONSTITUTION: A lock plate 9 is erected inside a back plate 2 and a hook 9a is installed on the tip of the lock plate 9. In a shoe hold spring 17, a hook 17d is installed on the tip of a band piece for connecting 17c by cutting up the band piece 17c for connecting whose stand up base part is the other side piece 17b side. The hook 17d is projected between a web 3a and the back plate 2 by passing the tip side of the band piece 17c for connecting through the inserting hole 3c of the web 3a and the hook 17d is engagingly attached to the hook 9a of the lock plate 9 while pressing the other side piece 17b of the shoe hold spring 17 in the web 3a direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal expansion type vehicle drum brake which expands a brake shoe in a back plate to perform a braking action. More specifically, the present invention relates to a back plate using a shoe hold spring. The present invention relates to a shoe hold device that elastically holds a brake shoe.

[0002]

2. Description of the Related Art In an internal expansion type drum brake used in an automobile or the like, a pair of brake shoes arranged to face each other inside a back plate is, for example, an actual open flat plate 5-52377.
No. and Jikkou Sho 48-15031, Jikō Sho 36-33
It is designed to be supported by a holding device as shown in No. 208.

The shoe-holding device of (1) makes a web of a brake shoe engage with a shoe-holding spring,
By fixing the shoe hold spring to the web, forming the opening of the back plate to a size that allows the shoe hold pin to move integrally with the brake shoe, and moving the shoe hold spring and shoe hold pin together with the brake shoe. , The brake shoes can be moved smoothly.

In the shoe-hold device, one end of a leaf spring, which is a material for the shoe-hold spring, is formed into a bifurcated shape, and the other end of the leaf spring is formed as a hooking end portion to prevent the web from moving backward. It is arranged on the plate side, the hook end is bent into the fork on one end side, and is inserted into the through hole of the web, and the hook end is hooked on the opening of the back plate to reduce the number of parts to one. In this way, the workability of assembling and dismounting is improved and the management of parts is simplified.

Further, in the shoe-hold device, one end of the shoe-hold spring formed of a coil spring is hooked from the back plate side of the web through the through hole to the side opposite to the back plate, and an opening is provided in the back plate to provide the back plate. A locking tool is inserted into the opening from the outside of the plate, and the hook at the other end of the shoe hold spring is locked to the locking tool to stretch the shoe hold spring.

[0006]

In the above-mentioned configurations (1) to (5), since the back plate is opened to lock the shoe hold pin and the shoe hold spring, rainwater and dust enter the back plate through the opening, and The inner surface of the plate, the brake shoe, and the brake drum may be soiled or rusted, which may interfere with the operation of the brake shoe. Waterproof and dust-proof measures such as creating a special boot separately to block the opening. Was needed.

Further, in the conventional example, in order to hook the hooking end into the opening of the back plate, after inserting the hooking end into the opening, the entire shoe hold spring including the hooking end is rotated. However, since the rim for fixing the lining wraps around the outer peripheral side of the web, it is necessary to secure the size necessary to elastically release the brake shoe on the shoe hold spring while keeping the web anti-back. It was considered extremely difficult to rotate the shoe hold spring by sliding it without interfering with the rim on the side surface of the plate, and it was also difficult to confirm the catch between the hook end and the opening.

In view of this, the present invention does not require waterproof and dustproof measures inside the back plate, allows the brake shoe to be reliably held by one touch with a simple structure, and the resilience of the shoe hold spring with respect to the brake shoe. It is an object of the present invention to provide a shoe hold device for a drum brake for an in-expansion type vehicle, which is stabilized.

[0009]

In order to achieve the above-mentioned object, the present invention has a pair of brake shoes arranged opposite to each other on an inner surface of a back plate fixedly mounted on a vehicle body and parallel to the back plate of the brake shoe. One side piece of a shoe-hold spring formed by bending a strip-shaped leaf spring into a U-shape is brought into contact with the side surface of the web opposite to the back plate, the shoe-hold spring is compressed in the web direction, and the brake shoe is attached to the back plate. In an inner expansion type vehicle drum brake that is elastically movable in the radial direction, a locking plate is erected on the inner surface of the back plate, and the shoe hold spring is connected to the other side on one side as a rising base. The strip is cut and raised to form an engaging portion at the tip of the connecting strip, and the tip side of the connecting strip is passed through the insertion hole of the web. And protrudes between the back plate, the other side piece of the shoe-hold spring while pressing the web direction, is characterized in that it has engaged the engaging portion with the locking plate.

It is preferable that the engaging portion of the connecting strip and the locking plate be engaged slidably in the radial direction of the back plate. Further, regarding the shapes of the engaging portion and the locking plate of the connecting strip, at least one of them may be a hook and the other may be a hook or an opening.

[0011]

With this structure, since the engaging portion at the tip of the connecting strip is engaged with the locking plate on the back plate, it is not necessary to provide an opening in the back plate, and no waterproof / dustproof measures are required. Becomes Since the connecting strip and the locking plate are plate-shaped members, the connecting strip and the locking plate are slidably attached to the back plate in the radial direction of the back plate. The piece slides together with the diameter expansion and diameter reduction of the brake shoe, so that the connecting strip will not tilt due to the operation of the brake shoe, and the elastic force of the shoe hold spring against the brake shoe will be kept constant. To do. Further, the engagement between the engagement portion and the locking plate is a surface contact, and even if the shoe hold spring is placed on the web in a direction out of the setting, the engagement between the engagement portion and the locking plate results in the surface contact. , Is corrected in the set direction. One-touch operation that only pushes the other side piece without changing the direction of the shoe hold spring by making the engaging part of the connecting strip and the locking plate a combination of hooks and hooks and openings Then, the engaging portion and the locking plate can be engaged with each other.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The drum brake 1 includes a pair of bow-shaped brake shoes 3 inside a back plate 2 fixed to the vehicle body.
3 are arranged so as to face each other, and both brake shoes 3 and 3 are expanded to the outside in the radial direction of the back plate 2 and the outer lining 4
Is a leading & trailing type in which the brake action is performed by rubbing the inner peripheral surface of the brake drum 5 which rotates integrally in the direction of the arrow A. Each brake shoe 3 uses a shoe hold device 6 to back the intermediate portion of the web 3a. It is held by the plate 2.

Each brake shoe 3 has a back plate 2
The above-mentioned web 3a disposed in parallel with the web 3a,
The rim 3b is fixed at right angles to the outer arc surface of the rim, and the lining 4 is attached to the outer surface of the rim 3b. A circular insertion hole 3c is formed in the approximate center of the web 3a. Has been drilled.

Inside the back plate 2, a wheel cylinder 7 and an anchor 8 are provided with a central axle insertion hole 2a.
The locking plates 9 and 9 of the shoe hold device 6 are erected at a position that is fixed with the web 3a interposed therebetween and that faces the insertion hole 3c of each web 3a.
One ends 3d, 3d of the web 3 are supported by the tips of the pistons 10, 10 projecting from both ends of the wheel cylinder 7.
The other ends 3e and 3e of a are supported by the anchor 8, respectively.

Wheel cylinder 7 and axle insertion hole 2a
A strut 11 is installed between the webs 3a and 3a, and return springs 12 and 13 are stretched between the strut 11 and the webs 3a. On the outside of the anchor 8, the other ends 3e, 3e of the webs 3a, 3a are also provided.
A return spring 14 is stretched over the brake shoe 3,3, and the brake shoe 3,3 is
The diametrically retracted limit is regulated by the struts 11 while being constantly urged in the diameter reducing directions by 3 and 14.

The wheel cylinder 7 is supplied with hydraulic fluid that has been boosted by the driver's braking operation, and each piston 10
Pushes one end 3d of the web 3a, and the brake shoes 3,3 spread apart using the other ends 3e, 3e of the webs 3a, 3a as fulcrums. Braking is performed by rubbing against the peripheral surface. A parking lever 15 is pivotally supported on the trailing side brake shoe 3 by a support shaft 16 near one end 3d of the web 3a, and the parking lever 15 is used in addition to the hydraulic operation by the wheel cylinder 7. The braking action can be performed by the mechanical operation that was performed.

The shoe hold device 6 includes a web 3a.
It comprises a shoe hold spring 17 arranged on the side opposite to the back plate and the above-mentioned locking plate 9. The shoe-hold spring 17 is formed by bending a strip-shaped leaf spring into a U-shape and forming an outer long rectangular frame in which a U-shaped cut is made in the longitudinal direction of the leaf spring extending from the one side piece 17a side to the other side piece 17b. And the shoe hold spring 17
The inner tongue piece is cut and raised to form a connecting strip 17c. In the shoe hold spring 17 in the free state, the one side piece 17a and the other side piece 17b open outward in a V shape. Further, the connecting strip 17c passes through the elongated base of the shoe hold spring 17 from the rising base portion on the other side piece 17b side, is bent at a right angle toward the one side piece 17a, and projects from the one side piece 17a. The tip of the strip 17c is bent back into a substantially U shape to form a hook 17d.

The locking plate 9 extends along the radial direction of the back plate 2 which is the operating direction of the brake shoe 3.
It is firmly erected on the inner surface of the back plate 2 by fixing means such as welding. At the tip of the locking plate 9, a connecting strip 17 is attached.
Hook 9 bent back in a U shape similar to hook 17d of c
a is provided, and the tips of both hooks 9a and 17d are
Each is inclined outward.

In the shoe hold spring 17, the tip end side of the connecting strip 17c is inserted into the insertion hole 3c of the web 3a, and the one side piece 17a is brought into contact with the side of the web 3a opposite to the back plate so that the tip end of the connecting strip 17c. The side is projected between the web 3a and the back plate 2, the other side piece 17b is further pressed in the direction of the one side piece 17a, and the connecting strip 17c is pushed in. Then, the connecting strip 17c and the locking plate 9 Hooks 9a, 1
7d deepens the rubbing of the tips with an appropriate elastic force (FIG. 1), and eventually the rubbing of the tips is released, and the hooks 9a, 17d engage with each other (FIGS. 2, 3, 5). Due to this engagement, the other side piece 17 of the shoe hold spring 17
Since b is substantially parallel to the one side piece 17a, elastic force in the web direction acts on the shoe hold spring 17, and the brake shoes 3 are elastically held between the shoe hold spring 17 and the back plate 2 so as to be movable in the radial direction. .

In this embodiment, the connecting strip 17c is integrally formed with the U-shaped shoe hold spring 17 as described above, and the locking plate 9 is erected on the inner surface of the back plate 2.
Since the connecting strip 17c and the hooks 9a and 17d of the locking plate 9 are engaged with each other, the back plate 2 does not have an opening for the shoe hold device 6, and rainwater and dust enter the back plate 2 through the opening. Since it is eliminated, waterproof and dustproof measures such as boots can be eliminated.

Further, since the connecting strip 17c and the hooks 9a and 17d of the locking plate 9 are plate-shaped and both are bent back to the U-shape, the other side piece 17b of the shoe hold spring 17 is connected. Hook 9 with just one push
By engaging a and 17d, the brake shoe 3 can be elastically held so as to be movable in the radial direction of the back plate 2. It is not necessary to rotate and stop the shoe hold spring 17 as compared with the conventional example. Since there is no interference with the rim 3b, it is possible to sufficiently secure the size required for elastically ejecting the brake shoe 3 on the shoe hold spring 17. In addition, since the hooks 9a and 17d are engaged with each other by surface contact, the shoe hold spring 17 is attached to the web 3
Even if the hook 9a, 17d is placed on the side opposite to the back plate a little apart from the back side, the hooks 9a, 17d are engaged in the surface contact to direct the connecting strip 17c in the radial direction of the back plate 2, so that the shoe hold spring 17 is set to a predetermined position. Can be corrected in the direction of.

Further, since the tips of the hooks 9a and 17d of the locking plate 9 and the connecting strip 17c are inclined outwardly, the connecting strip 17c can be inserted while being displaced in its plate thickness direction. Even if there is, since the tips of the hooks 9a and 17d rub against each other with an appropriate elastic force, the hooks 9a and 17d can be engaged regardless of a slight deviation, and the hooks 9a and 17d can be attached and detached. Since it can be confirmed by the click feeling and sound of the snapping when the resilience is released, the assembly reliability is extremely high.

Further, since the locking plate 9 is erected in the radial direction of the back plate 2, the plate-shaped hook 9a,
Since 17d is widely engaged in the moving direction of the brake shoe 3, the brake shoe 3 is not only used for expansion and contraction, but also when the lining 4 is fully worn and the movement amount of the brake shoe 3 is expanded. Hook 1 of strip 17c
7d slides on the hook 9a of the locking plate 9, and the connecting strip 17
Since c can be slid together with the brake shoe 3 (FIG. 4), the connecting strip 17c does not tilt due to the operation of the brake shoe 3, and the elastic force of the shoe hold spring 17 against the brake shoe 3 is always maintained. It becomes possible to maintain a constant value and exert a stable braking force.

Further, in this embodiment, although the shoe hold spring 17 is integrally provided with the connecting strip 17c, the shoe hold spring 17 has a closed loop shape of an elongated rectangular frame, so that the one side piece 17a and the other side piece 17b. It is possible to effectively secure the rigidity force to the web 3a at the one side piece 17a, and the adhesion force to the web 3a is high at the one side piece 17a, and the pressing force against the one side piece 17a and the pulling force to the connecting band piece 17c at the other side piece 17b. Is high. Further, since the outer end side of the other side piece 17b of the shoe hold spring 17 is used as the rising base of the connecting strip 17c, a large elastic force of the shoe hold spring 17 can be effectively applied to the brake shoe 3.

FIG. 6 shows another embodiment of the present invention, which has the same structure as the above-mentioned embodiment except for the locking plate 20. The locking plate 20 includes a rising plate 20a and an inclined guide plate 20.
b, and the rising plate 20a and the inclined guide plate 20b are erected on the inner surface of the back plate 2 with the rising plate 20a and the inclined guide plate 20b directed in the radial direction of the back plate 2.

The stand-up plate 20a is provided with a connecting strip 17c.
The opening 20c for locking the hook 17d of the
The brake shoe 3 has a large width in the width direction a.
When the brake shoe 3 moves from the new lining 4 to full wear, the connecting strip 17c can be slid integrally without tilting.

Further, the inclined guide plate 20b is a strip for connection 1
7c is inclined in the same direction as the tip of the hook 17d, and reliably guides the hook 17d to the opening 20c while elastically ejecting the hook 17d and the engagement and engagement of the hook 17d and the opening 20c by releasing the elastic force. Can be effectively confirmed by.

The present invention, as shown in the above embodiment,
Both the engaging portion and the locking plate of the connecting strip may be hooks, or either one may be a hook and the other may be a hook or an opening that engages with this hook. The engaging portion may be an opening. The shape of the hook and the opening is not particularly limited as long as the engagement is difficult to remove. Also, as a binding guide between the engaging portion and the locking plate,
Although it is useful to incline the tip of the engaging portion or the locking plate, the present invention does not make any difference in practice if it is omitted.

[0030]

As described above, the present invention has a shoe in which a locking plate is erected on the inner surface of the back plate, and a strip-shaped leaf spring is bent in a U-shape on the side opposite to the back plate of the brake shoe web. The one side piece of the hold spring is brought into contact with the shoe hold spring, and the coupling band piece having the other side on one side as a rising base is cut and raised on the shoe hold spring to form an engaging portion at the tip of the coupling band piece. The leading end side of the connecting strip is projected between the web and the back plate through the insertion hole of the web, and the other side piece of the shoe hold spring is compressed in the web direction, while the engaging portion at the leading end is locked by the locking plate. Since it is attached to the back plate, it is not necessary to open an opening for the shoe hold device in the back plate, and rainwater and dust do not enter the back plate through the opening.
It is possible to eliminate the need for waterproof and dustproof measures such as boots.

Further, the engaging portion of the connecting strip and the locking plate are
By engaging the brake shoe so that it can slide in the radial direction of the moving back plate, the connecting strip can be braked even when the brake shoe expands and contracts, or when the lining wears and the brake shoe moves significantly. Since it can be slid together with the shoe, the connecting strips will not tilt due to the operation of the brake shoe, and the elastic force of the shoe hold spring against the brake shoe will always be kept constant, providing stable braking force. Will be able to.

Furthermore, the engaging portion of the plate-like connecting strip and the engaging plate are formed into a combination of hooks or a combination of a hook and an opening so that the direction of the shoe hold spring can be changed without changing the direction. The brake shoe can be held movably in the radial direction of the back plate with a one-touch operation by simply pushing in the side piece. Therefore, compared to the conventional example, it is not necessary to rotate and stop the shoe hold spring, and there is no interference with the rim. Therefore, ensure that the shoe hold spring has a sufficient size to repel the brake shoe. You can Further, since the engagement between the engagement portion and the locking plate is in surface contact, even if the shoe hold spring is placed on the side opposite to the back plate of the web with a slight deviation, the surface contact between the engagement portion and the locking plate will occur. In the garment,
It is possible to correct the connecting strip and the shoe hold spring in a predetermined direction.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing an engaging part of a connecting strip and an engaging plate of an engaging plate.

FIG. 2 is a front view of a drum brake showing an embodiment of the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a cross-sectional view of essential parts showing a state where the brake shoe of FIG. 3 has moved outward due to wear of the lining.

FIG. 5 is a perspective view of an essential part showing a state in which the engaging portion of the connecting strip and the locking plate are engaged with each other.

FIG. 6 is a perspective view of a drum brake main part showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Drum brake 2 ... Back plate 2a ... Axle insertion hole 3 ... Brake shoe 3a ... Web of brake shoe 3 3b ... Rim of brake shoe 3 3c ... Penetration hole of brake shoe 3 3d ... One end of web 3a 3e ... Web 3a Other end 4 ... Lining of brake shoe 3 5 ... Brake drum 6 ... Shoe hold device 9 ... Locking plate 9a ... Hook 17 formed by bending back the tip of the locking plate 9 into a substantially U shape 17 ... Shoe hold spring 17a ... One side piece of shoe hold spring 17b ... Other side piece of shoe hold spring 17c ... Connecting band piece 17d integrally formed with the shoe hold spring 17 ... Bending the tip of the connecting band piece 17c back to a substantially U shape. Formed hook 20 ... Locking plate 20a ... Standing plate 20b of locking plate 20 ... Standing plate 20a Rotational direction of the hook A ... brake drum 5 the hooks 17d of the continuous inclined guide plate 20c ... connecting strip 17c is engaged

Claims (3)

[Claims] 1. A pair of brake shoes are arranged opposite to each other on the inner surface of a back plate fixed to a vehicle body, and a strip-shaped leaf spring is U-shaped on the side opposite to the back plate of the web parallel to the back plate of the brake shoe. Drum for inward expansion vehicle in which one side piece of a shoe-hold spring bent in a circular shape is brought into contact with the shoe-hold spring and the shoe-hold spring is compressed in the web direction to elastically hold the brake shoe in a radial direction of the back plate. In the brake, a locking plate is erected on the inner surface of the back plate, and the shoe hold spring is cut and raised to a connecting strip having the other side as a stand-up base, and is engaged with the tip of the connecting strip. The shoe hole is formed by forming a joint portion and projecting the tip end side of the connecting strip through the insertion hole of the web between the web and the back plate. A shoe hold device for an inner expansion type vehicle drum brake, wherein the engaging portion is engaged with the locking plate while pressing the other side piece of the door spring in the web direction. 2. The drum for an inflatable vehicle according to claim 1, wherein the engaging portion of the connecting strip and the locking plate are engaged so as to be slidable in the radial direction of the back plate. Brake shoe hold device. 3. The internal expansion according to claim 1, wherein one of the engaging portion of the connecting strip and the locking plate is a hook, and the other is a hook or an opening. Shoe hold device for drum brakes for type vehicles.