JPS5913387Y2 - Lining gap adjustment device for drum type brakes - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lining gap adjustment device for a drum type brake, and is particularly suitable for adjusting the gap between a brake shoe and a drum by rotating an adjustment cam pivotally supported on a brake shoe holding plate. The present invention relates to a brake lining gap adjustment device that allows the brake lining gap to be easily adjusted by operating with one hand without using a thickness gauge or the like.

As is well known, the drum type brake device in vehicles etc.
A brake shoe, which is pivotally attached to a brake shoe holding plate, is expanded and pressed against the inner circumferential surface of a drum that rotates with the wheel, thereby performing a braking operation.

Due to repeated use of the brake device, the lining attached to the brake shoes wears out, and the gap between the brake shoes and the drum when not braking becomes excessive.

Therefore, in this case, it is necessary to adjust the gap between the brake shoe and the drum by moving the position of the brake shoe when not braking toward the drum.

FIG. 1 is a schematic front view of a drum type brake device having such a gap adjustment mechanism, in which the heel portions of a pair of brake shoes 2 are attached to a brake shoe holding plate (back plate) 3 fixed to the vehicle body. 2a is pivotally connected, and its tip 2b
is connected to a hydraulic cylinder 4, and the brake shoe 2 is expanded outward by the urging force of the hydraulic cylinder 4, and the lining 5 on the outer surface of the shoe is pressed against the drum 1.

6 is a return spring for the brake shoe 2.

An adjustment cam 7 is pivotally supported on the brake shoe holding plate 3, and a guide pin 8 that contacts the cam 7 is attached to the brake shoe 2. By rotating this cam 7, the brake shoe is adjusted via the guide pin 8. Change the position of 2.

In this type of conventional gap adjustment mechanism, when manually rotating the cam shaft (not shown) of the adjustment cam 7, it is difficult to detect the rotation amount by hand movement, and it is difficult to detect the rotation angle of the cam, the lining, Unable to accurately grasp the relationship with the gap between the drums, it was extremely time-consuming to insert the thickness gauge between the lining 5 and the drum 1 with one hand while rotating the adjustment cam with the other hand. Such an operation was required.

The present invention eliminates these problems and is a drum-type brake device that allows the amount of rotation of the adjustment cam to be directly detected manually, thereby making it possible to easily adjust the gap between the lining and the drum with just one hand. An object of the present invention is to provide a lining gap adjustment device.

The gap adjusting device according to the present invention is a device for adjusting the gap between a brake shoe and a drum by rotating an adjusting cam pivotally supported on a brake shoe holding plate of a drum type brake, in which the gap between the brake shoe holding plate and the adjustment cam is adjusted. A pair of rooks fixed to the camshaft of a cam are installed between the brake shoe holding plate and the camshaft, and the camshaft is moved in its axial direction so that the rooks of the second set are always engaged with each other. and a spring member biased against the brake shoe, and the rook fixed to the camshaft slides relative to the rook fixed to the brake shoe holding plate by rotation of the adjustment cam.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a longitudinal sectional view along the camshaft of a lining gap adjusting device according to an embodiment of the present invention.

A cam shaft 9 of an adjusting cam 7 is inserted into the brake shoe holding plate 3, and a square or hexagonal portion 9a formed at the rear end of the cam shaft 9 is manually rotated using a tool such as a spanner.

A flange portion 9b is formed on the camshaft 9 adjacent to the adjustment cam 7, and the end surface of this flange portion comes into contact with the brake shoe holding plate 3.

A fixed rook 10 is fixed to the brake shoe holding plate 3 on a surface opposite to the surface that contacts the flange portion 9b.

Further, a movable rook 13 that engages with the fixed rook 10 is attached to the camshaft 9.

The movable flywheel 13 rotates together with the camshaft 9 when the camshaft 9 rotates, but is held so as to be movable in the axial direction of the camshaft.

The end face of the movable rook 13 is always pressed so as to engage with the end face of the fixed rook 10 by a compression coil spring 12 mounted on the outer periphery of the camshaft 9.

11 is a stop washer attached to the camshaft 9 for holding the compression coil spring 12.

In addition to interlocking the fixed and movable rooks 10.13 as described above, this compression coil spring also has the following functions:
The brake shoe holding plate 3 is sandwiched between the flange portion 9b of the camshaft 9 and the movable rook 13 to ensure that the camshaft 9 is held on the brake shoe holding plate 3.

These rooks 10, 13 have a plurality of claws inclined in one direction, as shown in FIG. 3, formed on the end faces thereof.

The ridges of the winter melon's mountains and valleys extend radially at the end of the rook.

FIG. 4 is an enlarged side view showing a state in which the fixed rook 10 and the movable rook 13 are engaged.

As is clear from the figure, the pawls of the rooks 10 and 13 are formed with the same pitch and the same slope, so that the ridges of the pawls of one rook fit into the troughs of the pawl of the other rook. do.

In this state, the camshaft 9 is moved to the fourth position in order to adjust the lining gap.
When rotated in the direction of arrow A in the figure, the movable rook 13 moves toward the coil spring against the spring force of the compression coil spring 12 and rotates together with the camshaft 9, causing the engaged pawl to slip. As soon as the nails are removed, the nails are engaged again.

When the pawls are once disengaged and then re-engaged, the pawls of the rook 10.13 collide with each other due to the spring force of the compression coil spring 12, producing an impact sound such as a click, or a turning force is generated every pitch rotation of the movable rook. Change occurs.

Therefore, one impact sound causes the camshaft 9 to move one of the movable rooks 13.
The operator's ears can sense that the camshaft has rotated by the pitch, or changes in turning force can be sensed by the feel of the hand while operating the camshaft.

The shape of the adjusting cam 7 is designed so that when the shaft 9 is rotated in the direction of arrow A in FIG. 4, the brake shoe 2 moves toward the drum 1 (FIG. 1), that is, the brake gap between the lining becomes smaller. By knowing in advance the relationship between the amount of rotation of the camshaft 9 and the amount of movement of the brake shoe 2, the gap between the lining and the drum can be adjusted to an appropriate amount without counting the approximate number of impact sounds generated. There is no need to measure the gap using a conventional thickness gauge or the like during adjustment work.

Adjustment work can be done with one hand, and accurate gap adjustment is possible without unnecessary adjustment of the gap (over-adjustment).

[Brief explanation of the drawing]

Fig. 1 is a schematic front view of a drum type brake device having a conventional lining gap adjustment mechanism, Fig. 2 is a longitudinal sectional view of a lining gap adjustment device according to an embodiment of the present invention, and Fig. 3 is a schematic front view of a drum type brake device having a conventional lining gap adjustment mechanism. FIG. 4 is a perspective view of such a rook, and is an enlarged side view showing a state in which a fixed rook and a movable rook are engaged. 2... Brake shoe 3... Brake shoe holding plate, 7... Adjustment cam, 9... Cam shaft, 1o... Fixed rook, 12... Compression coil spring, 13... Movable rook.

Claims (1)

[Scope of utility model registration request] In a device that adjusts the gap between a brake shoe and a drum by rotating an adjustment cam pivotally supported on a brake shoe holding plate of a drum type brake, one fixed to the camshaft of the brake shoe holding plate and the adjusting cam, respectively. a spring installed between the set of ratchet wheels, the brake shoe holding plate and the camshaft, and urging the camshaft in the axial direction so that the set of ratchet wheels always engage with each other; A lining gap adjustment device for a drum type brake, comprising a member, wherein a ratchet wheel fixed to the camshaft slides with respect to a ratchet wheel fixed to the brake shoe holding plate by rotation of the adjustment cam.