JPH066302Y2 - Drum brake - Google Patents

Description

TECHNICAL FIELD The present invention relates to a drum brake.

Prior art A pair of brake shoes, a strut bridged between the brake shoes, and a state in which the strut has a predetermined gap and is inserted through the inside of one end of the strut located on one side of the brake shoe. And a coil-shaped anti-rattle spring which is provided between the one brake shoe and the strut in a predetermined preload state and constantly urges the strut to the other brake shoe side to prevent rattling of the strut. Drum brakes are known.

Problems to be solved by the invention However, in such a drum brake, rattling in the longitudinal direction of the strut is preferably prevented based on the biasing force of the anti-rattle spring. Due to the fact that the strut is inserted with a certain amount of rattling, the strut moves in a direction substantially perpendicular to the longitudinal direction (anti-rattle spring radial direction) in the anti-rattle spring during vibration while the vehicle is running. There was a possibility of rattling and abnormal noise.

Means for Solving Problems The present invention has been made in view of the above circumstances, and its purpose is to play in a direction substantially perpendicular to the longitudinal direction of the struts in the anti-rattle spring. It is to provide a technique for effectively preventing contact. In order to achieve such an object, the present invention, in the drum brake as described above, elastically abuts the strut by bending a portion of the anti-rattle spring in the circumferential direction toward the inner circumferential side. It is characterized in that an abutting portion that comes into contact is provided.

According to this structure, the anti-rattle spring is provided with the abutment portion that elastically abuts the strut in the radial direction of the anti-rattle spring. It is possible to effectively prevent rattling in the spring in a direction substantially perpendicular to the longitudinal direction, and to effectively prevent generation of abnormal noise due to rattling of the struts.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing a duo servo type drum brake to which the present invention is applied, which is used as a parking brake mechanism of a drum-in disc brake, for example. In the figure, a pair of brake shoes 12 and 14 are supported on a backing plate 10 by shoe hold down devices 16 and 18 so as to be able to expand each other.
The brake shoes 12 and 14 are arc-shaped and plate-shaped shoe rims 20 and 22, and plate-shaped shoe webs 24 and 26 projecting from the inner peripheral sides of the shoe rims 20 and 22 and positioned substantially parallel to the backing plate 10. And the opposite ends of the shoe webs 24 and 26 are urged by springs (not shown) toward each other, and their axial lengths are variable. The both ends of the adjuster 28 are engaged with each other. On the other hand, the other ends of the shoe webs 24, 26 are adapted to be brought into contact with the side surfaces of the anchor pins 30 fixed on the backing plate 10, respectively.
The shoe return spring 3 stretched between the anchor pin 30 and both brake shoes 12 and 14.
It is always urged by 2, 34 in a direction toward each other. A parking brake lever 36 having a parking cable (not shown) connected to one end is rotatably attached to the other end of the one brake shoe 12 (anchor pin 30 side) at the other end. Struts 40 between the brake shoes 12 and the parking brake lever 36 and the brake shoe 14 sandwich the shoe web 24, the parking brake lever 36 and the shoe web 26 at both ends thereof in the plate thickness direction, and adjusters. 28 and a state in which relative movement with respect to the shoe webs 24, 26 and the parking brake lever 36 in the direction of approaching and separating from the anchor pin 30 is substantially blocked, and is constantly urged toward the brake shoe 12 by the anti-rattle spring 38. Rack It has been passed. The operation of the duo-servo type drum brake is well known and is not always necessary for understanding the present invention, so a detailed description thereof will be omitted.

The anti-rattle spring 38 is shown in FIGS.
As shown in the drawing, the anti-rattle spring 38 has a coil shape and is inserted into the strut 40 at one end of the strut 40 located on the side of the brake shoe 14 with a predetermined gap. The shoe return springs 32, 34 are provided in a state in which relative movement of the strut 40 to the other end side is blocked by contact between one end in the direction of the strut 40 and a pair of stoppers 42 protruding from the strut 40. The other end of the anti-rattle spring 38 in the axial direction is brought into contact with the shoe web 26 in a predetermined preload state in accordance with the urging force of. As a result, the strut 40 is constantly urged toward the brake shoe 12 by the anti-rattle spring 38, and rattling in the longitudinal direction of the strut 40 is prevented owing to the urging force. In this embodiment, the brake shoe 14 corresponds to one brake shoe, and the brake shoe 12 corresponds to the other brake shoe.

Here, in the anti-rattle spring 38, as shown in FIG. 1, a part of the circumferential direction is bent toward the inner circumferential side over the entire length in the direction parallel to the axial center, so that the contact portion 44 is formed. Are integrally provided with the strut 40.
Is elastically brought into contact with the surface of the adjuster 28 side. As a result, the strut 40 is in a direction substantially perpendicular to the longitudinal direction of the strut 40 in the anti-rattle spring 38 (radial direction of the anti-rattle spring 38) when the vehicle vibrates during traveling, and the strut 40 moves up and down in FIGS. 1 and 2. The rattling in the direction is effectively prevented, and the generation of abnormal noise due to the rattling of the strut 40 is effectively prevented. In this case, based on the frictional resistance between the contact portion 44 and the strut 40 and the like, rattling in the anti-rattle spring 38 in a direction substantially perpendicular to the longitudinal direction of the strut 40 and in the left-right direction in FIG. Can be prevented to some extent.

In the embodiment described above, the anti-rattle spring 38 is provided with the contact portions 44 only at one position in the circumferential direction, but it is not always necessary to provide the contact portions 44 at plural positions in the circumferential direction. Is also good. In this case, it is possible to effectively prevent rattling of the strut 40 in the vertical direction and the horizontal direction in FIG.

Further, in the above-described embodiment, the contact portion 44 is provided over the entire length in the direction parallel to the axis of the anti-rattle spring 38, but this is not always necessary, and the contact portion 44 in the direction parallel to the axis may be provided. The contact portion may be formed by bending a part of the contact portion inward.

Further, in the above-described embodiments, the case where the present invention is applied to the duo servo type drum brake has been described, but it goes without saying that the present invention can be applied to other drum brakes.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is an enlarged view showing a main part of a cross section taken along the line II of FIG. FIG. 2 is a front view showing a main part of a drum brake to which the present invention is applied. 12, 14: Brake shoe 38: Anti-rattle spring 40: Strut 44: Contact part

Claims (1)

[Scope of utility model registration request] 1. A pair of brake shoes, a strut bridged between the brake shoes, and a strut having a predetermined gap on one end side of the strut located on one side of the brake shoe. A coil shape that is provided in a state of being inserted through the inside and in a predetermined preload state between the one brake shoe and the strut, and constantly urges the strut to the other brake shoe side to prevent rattling of the strut. In an anti-rattle spring, the anti-rattle spring is provided with an abutting portion that elastically abuts the strut by bending a part of the spring in the circumferential direction toward the inner circumferential side. A drum brake characterized by.