JPS6023562Y2 - Shu hold down spring - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a shoe hold down spring that prevents a pair of brake shoes from floating up from a backing plate in a drum brake.

In a drum brake, a shoe hold-down spring is used that presses the brake shoe against a backing plate with a certain elastic force in order to prevent the brake shoe from vibrating or floating.

Various types of shoe hold down springs are known, one of which is a substantially U-shaped leaf spring with a pair of opposing plate portions.

As an example of this type of shoe hold down spring is shown in FIG. 7 is engaged with the head 4a of the shoe hold down pin 4.

The shoe hold-down pin 4 is attached to the backing plate 1, and is provided at the tip thereof passing through the backing plate 1, the brake shoe web 2, and the two plate-like parts 3a and 3b of the shoe hold-down spring 3. The head 4a is engaged with the engaging portion 7.

In this way, the shoe hold down spring 3 is installed between the brake shoe web 2 and the shoe hold down pin 4, and presses the brake shoe web 2 with a constant elastic force to prevent it from floating up from the backing plate 1. It is.

Conventionally, the above-mentioned retaining part provided on the plate-shaped part is provided only on one plate-shaped part, so when installing the shoe hold down spring, select the plate-shaped part provided with this engagement part. So, it was necessary to position this so that it was on the side away from the brake shoe web.

However, selecting the assembly one by one on the assembly line is troublesome and causes a decrease in work efficiency.

In addition, if the two plate-like parts are placed incorrectly, it will be time-consuming to remove the shoe hold-down spring from the shoe hold-down pin that has been inserted and place it in the correct direction again, which will reduce work efficiency. This will encourage

This invention was made against the background of the above circumstances, and its purpose is to ensure that the assembly of the two plate parts has no selectivity in direction, that is, which plate part is attached to the brake shoe web. An object of the present invention is to provide a shoe hold-down spring that can be attached to a brake shoe web or placed on a side away from a brake shoe web.

To distantly related to this object, the present invention engages with a retaining protrusion of a shoe hold-down pin attached to a backing plate of a drum brake, and also abuts against a brake shoe web to release the brake shoe from the backing plate of the brake shoe. A shoe hold-down spring that prevents the floating of the
It consists of a letter-shaped leaf spring, and a portion of the pair of plate-like parts is recessed inward, and an engaging recess to be engaged with the head of the shoe hold-down pin is located at the opposite side of the pair of plate-like parts. It is characterized by being formed at positions facing each other.

The present invention will be explained in more detail below based on embodiments shown in the drawings.

In FIGS. 2 and 3, reference numeral 11 denotes a backing plate, and a shoe hold pin 13 is attached to the backing plate 11, which passes through the backing plate 11 and the shoe web 12 of the brake shoe 31, respectively.

A shoe hold down spring 1 is provided between the shoe hold down pin 13 and the brake shoe web 12.
4 is attached to prevent the brake shoe web 12 from floating away from the backing plate 11.

This shoe hold down spring 14 is formed from a substantially U-shaped leaf spring having a pair of opposing plate portions 15, 16 and a curved portion 19.

The plate-like parts 15 and 16 move away from each other as they move toward the curved part 19 from the tip side, and then approach each other to form the curved part 19.
The retaining part/stopper part 21, 22 and the contact parts 17, 18 which are to be brought into contact with the brake shoe web 12 are formed at the parts farthest from each other.

The engaging portion/stopper portion 21.22 is formed by recessing the mutually opposing portions of the plate-like portions 15.16 inwardly (when viewed from the inside, protrusions are formed). The shape of the recess is suitable for fitting the shoe hold down pin head 13a.

The height of the protrusion h) in FIG. 2 is such that when the shoe hold down spring 14 is elastically deformed, one of the engaging portions/stopper portions 2 reaches its elastic limit, that is, the yield point.
The inner surface 23 of the shoe return spring 14 is set so as to come into contact with the inner surface 24 of the opposing engaging portion/stopper portion 22 to prevent further deformation of the shoe return spring 14.

Circular holes 25, 26 and longitudinal slits 27, 28 whose longitudinal direction is perpendicular to the width direction of the plate-shaped portion are formed at the bottom of the recess forming the engaging portion/stopper portion 21, 22, and the shoe hold is formed. The head 13a of the down pin 13 is allowed to pass through.

The abutting portions 17 and 18 are formed as a result of providing the recessed portions serving as the engaging portions and stopper portions in the farthest portions of the plate portions 15 and 16.

The shoe hold down spring 14 is assembled as follows.

Insert the shoe hold down pin 13 from the head side into the backing plate 11, brake shoe web 12. Plate portion 16
The head 13a passes through the slit 27 provided in the plate-like part 15 by pressing the other plate-like part 15 at the position A indicated by the two-dot chain line in FIG. 2 toward the brake shoe 12. also pass through.

Thereafter, the shoe hold down pin 13 is rotated 90 degrees to release the plate portion 15, and the head 13a is fitted into the fitting portion/stopper portion 21, completing the assembly of the shoe hold down spring 14.

At this time, the plate-shaped portion 15 is prevented from further deformation by the engagement portion/stopper portion 21 coming into contact with the opposing engagement portion/stopper portion 22, so that the plate portion 15 does not deform beyond the elastic limit.
That is, permanent deformation is prevented.

Therefore, a stable set load can be applied to the shoe hold down spring 14, and the operator can deform the shoe hold down spring 14 with peace of mind during assembly, thereby improving work efficiency.

In addition, this shoe hold down spring 14 has two plate-like parts 15 and 16 that are symmetrical in shape, and each of them is provided with retaining parts and stopper parts 21° and 22, so that the assembly can be performed in any direction. There is no selectivity.

In other words, it is no longer necessary to select and check each plate-like part on which the retaining part is provided, so that work efficiency is greatly improved.

Further, since the shoe hold down spring 14 is configured to contact the brake shoe web 12 only at the contact portions 17 and 18 formed on the plate portion 15.16, the elastic force of the shoe hold down spring 14 is Brake shoe web 1 by contact parts 17 and 18
2 will be informed.

The contact portions 17 and 18 are formed very close to the shoe hold down pin 13, and the shoe hold down pin 13 is generally attached to the center of the sliding resistance of the brake shoe web 12 against the backing plate 11. The elastic force of the shoe hold-down spring 14 acts precisely on the center of resistance of the brake shoe web 12.

Therefore, as illustrated in FIG. 1, almost the entirety of one plate-shaped portion 3a is in contact with the brake shoe web 12, and therefore, compared to the conventional brake shoe web 12 in which the elastic force does not necessarily act on the center of the sliding resistance, the shoe When the hold-down spring 14 is used, the entire sliding portion of the brake shoe 31 against the backing plate can be pressed with an even force, and the brake shoe 31 can properly slide when the brake is applied or released. be.

As described in detail above, the present invention is such that each plate-shaped portion of the leaf spring serving as the shoe hold down spring is provided with an engaging portion that engages with the shoe hold down pin. The assembly eliminates directional selectivity and improves work efficiency.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of a conventional shoe hold-down spring installed, FIG. 2 is a front view showing an installed shoe hold-down spring according to an embodiment of the present invention, and FIG. The figure is an enlarged perspective view taken along the line ■-■ in FIG. 2, and FIG. 4 is an enlarged perspective view of the main part of the shoe hold down pin in FIGS. 2 and 3. 11: Backing plate, 12 Brake web, 14: Shoe hold down swing, 1, 1
6: Plate-shaped portion, 17.18: Contact portion, 21, 22: Engagement portion and stopper portion.

Claims (1)

[Claim for Utility Model Registration] Engages with the engagement protrusion of the shoe hold-down pin attached to the backing plate of the drum brake, and also comes into contact with the brake shoe web to prevent the brake shoe from floating up from the backing plate. The shoe hold-down spring has a substantially U-shaped plate spring having a pair of opposing plate-shaped parts, and a part of the pair of plate-shaped parts is recessed inward, and the above-mentioned A shoe hold down spring characterized in that engaging recesses to be engaged with the head of the shoe hold down pin are formed at opposing positions of the pair of plate parts.