JPS6221800Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention has one end of a pair of brake shoes slidably supported on a back plate abutting an anchor, and a brake shoe expanding means provided at the other end to allow the brake shoes to expand. Both ends of the strut are brought into contact with the shoe web near the means, and the feed pawl of the adjustment lever rotatably provided on the shoe web is engaged with the adjustment gear of the strut.By rotating this adjustment gear, the strut is extended and the braking gap is closed. The present invention relates to an automatic braking gap adjustment device for a vehicle drum brake that automatically adjusts the braking gap.

Conventionally, in this type of automatic braking gap adjustment device, when the lining reaches its wear limit and the brake shoe is replaced, or when the brake system is repaired, the drum is removed and the adjustment lever is lifted up with a tool or the like to engage with the adjustment gear. The situation has been resolved, and the brake shoe has been replaced and various parts of the brake system have been repaired. In addition, if the lining of the brake shoe is biting into the braking surface of the drum and the drum cannot be removed, insert a tool through the window provided in the back plate and remove the adjustment lever that is meshed with the adjustment gear from the adjustment gear. The gear is pushed away to release the engaged state, and the adjustment gear is rotated in the opposite direction to retract the strut, thereby removing the drum and replacing the brake shoe or repairing the brake device.

To release the engagement between the adjustment lever and the adjustment gear, for example, use a tool such as a screwdriver to push up the adjustment lever to release the engagement between the feed pawl and the adjustment gear, and use another tool to reverse the adjustment gear. be. Therefore, at least two tools were required.

The present invention was devised in view of the above circumstances, and includes a locking piece formed on the return spring side of the adjustment lever, and the locking piece is engaged with the return spring when the adjustment lever and the adjustment gear are disengaged. Its purpose is to enable the adjustment gear to be reversed by releasing the engagement between the adjustment lever and the adjustment gear with a single tool when replacing the brake shoe.

An embodiment of the present invention will be described below with reference to the drawings.

1 is a back plate fixed to the vehicle body;
In the figure, a wheel cylinder 2 is fixed at an upper position, and an anchor 3 is fixed at a lower position.
4, 4 are a pair of brake shoes disposed within the back plate 1, with shoe webs 4a, 4a,
Shurim 4b, 4b and lining 4c, 4
It consists of c. One end of the shoe webs 4a, 4a of the pair of brake shoes 4, 4 is in contact with a pair of pistons 5 of the wheel cylinder 2, and the other end is in contact with the left and right ends of the anchor 3, respectively. Both brake shoes 4, 4 are expanded so that the linings 4c, 4c come into sliding contact with the inner peripheral surface (not shown) of the brake drum.

6 is the shoe web 4 with one end on the trailing side.
7 is a second strut whose one end is in contact with the leading side shoe web 4a; 8 is an adjustment bolt having an adjustment gear 9 in the middle; its threaded portion 8a is screwed into the first strut 6; The straight portion 8b is rotatably fitted into the second strut 7.

Reference numeral 10 denotes an adjustment lever rotatably provided on the leading side shoe web 4a, a feed pawl portion 10b formed on the main body 10a meshes with the adjustment gear 9, and a tongue piece 10d formed on the base portion 10c.
is in contact with the notch 7a of the second strut 7, and the other end of the adjuster lever spring 11, which has one end locked in the leading side shoe web 4a, is locked in the main body 10a. As a result, the adjustment lever 10 rotates clockwise in FIG. 1 when the brake shoes 4, 4 are expanded, and as the linings 4c, 4c wear out, the feed pawl portion 10b rotates the adjustment gear 9, thereby adjusting the adjustment lever 10. Bolt 8 first
The lining 4c is screwed out from the strut 6 to extend the first strut 6 and the second strut 7.
Adjust the braking gap between 4c and the drum (not shown).

Reference numeral 12 denotes an arm portion integrally formed with the main body 10a of the adjuster lever 10. The arm portion 12 is bent downward from the wheel cylinder 2 side near the feed pawl portion 10b to form a hooking piece 12a, and the tip thereof is attached to the inside of the back plate. It is bent to the side to form a tool pressing surface 12b parallel to the back plate 1, and a tool engaging groove 12c is formed in the pressing surface 12b. Reference numeral 13 denotes a window formed near the adjustment gear of the back plate 1. Normally it is blocked by a stopper 14, and when the lining is biting into the braking surface of the drum and the drum cannot be removed, a tool can be inserted through the window 13. Insert the drum, rotate the adjustment gear 9 in the opposite direction, retract the brake shoes 4, 4 inward, and remove the drum.

Reference numeral 15 denotes a return spring, and a locking member 16 provided to protrude upward from the shoe webs 4a, 4a.
16 and lock both ends of the brake shoes 4, 4.
is always urged in the direction of approaching. The locking piece 12a of the adjustment lever 10 is formed so as to be engaged with the straight portion 15a of the return spring 15 when the feed pawl portion 10b is removed from the adjustment gear 9.

Next, the operation of this embodiment will be explained.

When replacing the brake shoe after the lining has reached its wear limit due to repeated braking, or when repairing the brake system, first remove the drum, then pry up the adjuster lever 10 using a tool, etc. The engagement state between the feed pawl portion 10b and the adjustment gear 9 is released, the adjustment gear 9 is rotated in the opposite direction, the brake shoes 4 are removed, and the brake shoes 4, 4 are replaced with new brake shoes or the various parts are repaired.

If the linings 4c, 4c are biting into the braking surface on the inner circumference of the drum and the drum cannot be removed, remove the stopper 14, insert a tool through the window 13 of the back plate 1, and insert the tip of the tool into the adjuster lever 10. The locking piece 12a of the adjusting lever 10 is engaged with the tool engagement groove 12c and pushes the adjusting lever 10 in the direction in which the feed pawl portion 10b separates from the adjusting gear 9 to release the meshing state between the adjusting gear 9 and the feeding pawl portion 10b. is engaged with the linear portion 15a of the return spring 15 to temporarily fix the adjustment lever, and then the adjustment gear 9 is reversed using the tool to contract the struts 6 and 7, thereby removing the drum and removing the brake shoe 4. , 4 and repairs each part.

Since the present invention is configured as described above, when releasing the adjustment lever and the adjustment gear, the adjustment lever can be temporarily fixed to the return spring, and therefore the adjustment gear can be easily reversed with a single tool. can be done.

[Brief description of the drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a front view, FIG. 2 is a cross-sectional view of FIG. 1, and FIG.
The figure is a cross-sectional view taken from the side shown in FIG. 1, and FIG. 4 is a perspective view of the adjustment lever. 4, 4 are brake shoes, 4a, 4a are shoe webs, 4b, 4b are shoe rims, 4c, 4
c is the lining, 6 is the first strut, 7 is the second strut
10 is a strut, 8 is an adjustment bolt, 9 is an adjustment gear, 10 is an adjustment lever, 10a is a main body, 10b is a feed claw thereof, 12 is an arm, 12
a is a hook, 15 is a return spring, 15a
is the straight part.

Claims (1)

[Scope of utility model registration request] One end of a pair of brake shoes slidably supported on a back plate is brought into contact with an anchor, the other end is provided with a brake shoe expansion means, a return spring is stretched between the brake shoes, and a return spring is placed in the vicinity of the return spring. Both ends of the strut are brought into contact with the shoe web of the strut, and the feed pawl of the adjustment lever rotatably provided on the shoe web is engaged with the adjustment gear of the strut.By rotating the adjustment gear, the strut is extended and the braking gap is automatically adjusted. In the drum brake to be adjusted, a locking piece is formed on the return spring side of the adjustment lever, and the locking piece can engage with the return spring when the feed pawl of the adjustment lever and the adjustment gear are disengaged. An automatic braking gap adjustment device for a vehicle drum brake, characterized in that: