JPS5811948Y2 - Spring device for retracting brakes - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a spring device that eliminates the biasing force of a brake shoe in the axle direction, which is normally generated by a shoe retracting spring, in a vehicle brake.

Ideally, the spring force for returning the brake shoe to the retracted position can be applied in a plane perpendicular to the axle and at the center of the thickness of the shoe web, since no biasing force will be generated in the shoe in the axle direction.

However, due to layout constraints, it is often necessary to arrange the retraction spring along one surface of the shoe web.

In such a case, the shoe will be lifted off the back plate or a force will be applied to the shoe to press it against the back plate due to the retraction spring.

Therefore, the contact between the brake shoes and the back plate or the hold washer increases, and the frictional resistance between them increases, resulting in various problems.

That is, first of all, the return of the shoe when the brake is released becomes difficult, and the lining constantly contacts and drags the drum, causing a reduction in effectiveness due to heat generation of the lining and premature wear of the lining.

Also, since the shoe is biased to one side in the axle direction,
The sliding surfaces of the lining and drum cannot be parallel,
Especially for large brakes with wide lining widths, the clearance between the two must be larger than specified.
This causes the brake pedal stroke to be excessive.

In order to eliminate the above-mentioned problems, this invention has replaced the retraction springs that were conventionally placed only on one side of the shoe web with symmetrical placement on both sides of the shoe web. In addition, the hook at one end of the spring is formed into a substantially single piece, thereby further improving handling and detachability.

In this way, the frictional resistance and wear of each part due to the movement of the shoe will be almost eliminated, solving the problem of dragging, improving the durability of the parts, and ensuring the parallelism of the sliding surfaces of the lining and drum. Moreover, it becomes extremely easy to attach and detach the spring.

The present invention will be explained below with reference to the drawings. In the drawings, 1 is a brake shoe, 2 is a lining thereof, 3 is a rim, 4 is a web, 5 is a hole provided in the center of the web 4, and 6 is provided on both sides of the hole 5. 7 is a torque plate, 8 is an anchor that engages with one end of the web 4, and 9 is an adjuster that engages with the other end of the web 4, and is formed integrally with the anchor 8.

10 is a back plate; 11 is a hold pin implanted in the back plate 10; this hold pin 11 passes through the hole 5; a washer 12 and a nut 13 are fitted into the protruding portion of the hold pin 11; Excessive movement in the axial direction is restricted.

Reference numeral 14 supports the rim 3 with a ledge protruding from the back plate 10 to restrict movement of the brake shoe 1 in the axle direction.

15 is a wheel cylinder, 16 is a bushing rod protruding from the cylinder 15, and each of the rods 16 is engaged with an end of the brake shoe 1.

In the present invention, the spring 17 has coil portions 17a having substantially the same specifications on both sides of the web 4 of the brake shoe 1.
are arranged, and substantially one hook is formed at one end of these springs 17.

That is, as shown in FIGS. 1 and 2, one end of the retraction spring 17 is engaged with the hole 6 of the web 4, the other end is engaged with the spring hanger 18 embedded in the torque plate 7, and the brake shoe 1 is always returned to the retracted position.

The structure of the spring 17 is as shown in FIG.
a, and the hook 17b provided at one end is inserted into the hole 6 of the web 4.
engage with.

On the other hand, the other end of the spring 17 is a loop-shaped hook 17.
C, and the spring hanger 18 installed on the torque plate 7 engages with the web 4 of the brake shoe 1 on an extension of the center line of the plate thickness.

Since this spring 17 is made from a single wire, it has the advantage of being easy to manufacture and easy to handle.

FIG. 3 shows another structure of the spring 17, which is similar to that in FIG. 2 in that springs 17 having substantially the same specifications are arranged symmetrically on both sides of the web 4 of the shoe 1.

This spring 17 has a hook 17b provided at one end of the coil portion 17H that engages with the protrusion 3' of the rim 3, and a hook 17C provided at the other end of the coil portion 17a. These hooks 17C are connected to one end 19a of the holder 19.

A hook 19b that engages with the hanger 18 is formed at the other end of the holder 19.

This structure of the spring 17 has the advantage that the holder 19 can be articulated within a certain range relative to the hook portion 17C, making it extremely easy to attach and detach the spring 17 to the spring hanger 18.

Since this invention is constructed as described above, the brake shoe 1
No biasing force in the axle direction is applied to the shoe 1, and when the brake is applied and released, the frictional resistance against the movement of the shoe 1 is small, and the retracting force of the spring 17 can be effectively applied to the shoe 1.

Therefore, the drag of the shoe 1 is eliminated, and a reduction in effectiveness due to heat generation of the shoe 1 and early wear of the lining 2 can be prevented, and wear of the ledge 14 and washer 12 is also eliminated, improving the durability of the parts.

Further, since no biasing force is applied to the shoe 1, parallelism between the drum surface and the lining surface can be easily achieved, and the clearance between the two can be reduced, resulting in a reduction in brake pedal stroke.

Furthermore, since the load applied to each stripe rim is small, the stress on the spring can be reduced, which helps prevent spring breakage.

Furthermore, since the springs 17 disposed on both sides of the web 4 have approximately the same specifications, the springs 17 may be damaged due to wear of the lining 2.
Even if the spring expands, the spring force will not lose its balance,
The shoe 1 can be held in a well-balanced manner throughout the life of the lining, and the normally used hold spring is not required.

Furthermore, since the springs have almost the same specifications, they are suitable for mass production and are inexpensive.

In addition, although the spring has one hook 17C, (19) in effect, it is easier to handle because it can be handled as a separate component compared to a case where two or more types of springs are arranged on both sides of the web. In addition, since the spring hanger 18 can be engaged with a single operation, attachment and detachment can be carried out extremely efficiently, and there is no risk of incorrect assembly due to loss of the spring or forgetting to hook it. , the present invention has many effects.

[Brief Description of the Drawings] Fig. 1 is a front view showing an embodiment of the brake device equipped with the spring device of the present invention, Fig. 2 is a sectional view taken along line I-I in Fig. 1, and Fig. 3 is a main view of the brake device. FIG. 4 is a sectional view showing another spring device according to the invention, and FIG. 4 is a front view thereof. 1... Brake shoe, 2... Lining,
3...Rim, 4...Web, 5,6.
... Hole, 7 ... Torque plate, 10.
...Back plate, 17... Spring, 17a... Coil part, 17 b, 17
C... Hook part, 18... Spring hanger, 19... Holder, 19 a...
...One end of the holder 19, 19b...Hook part at the other end.

Claims (1)

[Scope of utility model registration request] Coil portions with substantially the same specifications are arranged on both sides of the brake shoe web, one end of each coil portion is engaged with the brake shoe, and the other end of each coil portion is connected to form substantially one hook portion. A spring device for retracting a brake shoe, wherein the hook portion is suspended from a locking member on an extension line of the center line of the approximate plate thickness of the web of the brake shoe.