Brake band

Abstract

In a brake band in which a bracket is coupled to an end portion of a curved strap and an apply pin comes into contact with a contact portion of the bracket, thereby generating a fastening force, an abrasion preventing means is provided between the contact portion of the bracket and the apply pin.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a brake band, for example, used in an automatic transmission of a motor vehicle or the like. More particularly, the present invention relates to a brake band provided with an abrasion preventing means for preventing an abrasion of a bracket.

2. Relevant Background Art

A brake band is constituted by an annular strap broken at one position, a bracket provided in a broken end portion of the strap, and a friction member firmly fixed to an inner periphery of the strap, and is structured such that the strap is wound around a drum by applying a force on the basis of an apply pin to the bracket in an apply side and a brake force is obtained.

However, the conventional brake band mentioned above has the following problem. There is a risk that an abrasion or a breakage is generated in a pin contact portion of the bracket on the basis of a load repeatedly applied to an apply pin pressure receiving portion of the apply side bracket and a malfunction is generated.

In order to solve the problem, for example, in Japanese Patent Application Laid-open No. H10-169675, the structure is made such that a leading end shape of the apply pin which has been conventionally brought into point contact with the apply side bracket is formed in a trapezoidal shape so as to be brought into line contact with the bracket.

However, in the countermeasure mentioned above, since the apply pin is directly in contact with the bracket, it is possible to obtain an effect that a degree of the abrasion is reduced in comparison with the point contact, however, a fundamental solution can not be obtained.

Further, as the other countermeasures, there can be considered to change a product specification, for example, reducing a hardness of the apply pin itself, making a thickness of the bracket so as to improve a strength of the bracket, changing a material of the bracket so as to increase a hardness, and the like. However, changing the product specification may generate a new problem such as an increase of a manufacturing cost or the like.

SUMMARY OF THE INVENTION

Accordingly, an object of the present-invention is to provide a brake band which employs the conventional structure and raw material as it is, covers a pin pressure receiving portion of a bracket or an apply pin by a cover member, and can reduce an abrasion of a pin contact portion of the bracket.

In order to achieve the object mentioned above, in accordance with the present invention, there is provided a brake band in which a bracket is coupled to an end portion of a curved strap and an apply pin comes into contact with a contact portion of the bracket, thereby generating a fastening force,

wherein an abrasion preventing means is provided between the contact portion of the bracket and the apply pin.

In accordance with the present invention, the following effect can be obtained.

It is possible to cover the contact portion of the bracket or the apply pin by the cover member without changing the conventional product specification, and it is possible to reduce the abrasion in the contact portion of the bracket.

Since it is possible to select the material in conformity with a hardness difference from the opposite member, it is possible to easily correspond to various use conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a brake band to which the present invention can be applied;

FIG. 2 is a front elevational view of a main portion of an apply side bracket and an apply pin and shows a first embodiment in accordance with the present invention; and

FIG. 3 is a front elevational view of a main portion of an apply side bracket and an apply pin and shows a second embodiment in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be in detail given below of the present invention with reference to the accompanying drawings. In this case, it goes without saying that an embodiment described below describes the present invention as an exemplification, and does not limit the present invention. Further, the same elements in each of the drawings are denoted by the same reference numerals.

FIG. 1 is a front elevational view of a brake band 10 to which the present invention can be applied. The brake band 10 has a strap 1 formed in an approximately annular shape and made of a thin steel plate, an apply side bracket 2 coupled to an end portion 1a of the strap 1, and an anchor side bracket 3 coupled to the other end portion 1b of the strap 1. A friction member 6 is adhered to an inner periphery of the strap 1 by an adhesive agent or the like. A drum (not shown) is fitted to an inner portion of the strap 1.

An anchor pin 5 is provided in the anchor side bracket 3, and holds the end portion 1b of the strap 1 in a fixed state. Further, an apply pin 4 driven by a drive mechanism (not shown) and having a piston function is brought into contact with the apply side bracket 2. The apply pin 4 presses the apply side bracket 2, thereby deflecting the strap 1, fastening the strap 1 to an outer periphery of a drum (not shown) in such a manner that the end portions 1a and 1b of the strap 1 come close to each other, and generating a brake force.

The apply side bracket 2 is provided with a contact portion 2a formed by folding. The contact portion 2a is provided with a pressure receiving surface 2b facing to the apply pin 4, and a leading end portion 4a of the apply pin 4 is brought into contact with the pressure receiving surface 2b.

Next, a description will be given of each of embodiments in accordance with the present invention provided with an abrasion preventing means, with reference to FIGS. 2 and 3.

First Embodiment

FIG. 2 is a front elevational view of a main portion of the apply side bracket 2 and the apply pin 4 and shows a first embodiment in accordance with the present invention. A cover member 20 covers an approximately whole of the contact portion 2a of the apply side bracket 2. Accordingly, a leading end portion of the apply pin 4 comes into contact through the cover member 20 without being directly brought into contact with the pressure receiving surface 2b of the contact portion 2a.

The cover member 20 is formed in a cap shape covering a whole of the contact portion 2a, however, does not necessarily cover the whole. In other words, since the cover member may be formed in a shape covering at least the pressure receiving portion 2b, the cover member 20 having a magnitude corresponding to an area of the pressure receiving portion 2b may be fixed to the pressure receiving portion 2b.

Second Embodiment

FIG. 3 is a front elevational view of a main portion of the apply side bracket 2 and the apply pin 4 and shows a second embodiment in accordance with the present invention. In the second embodiment, the structure is made such that the contact portion 2a of the apply side bracket 2 is not covered by the cover member, but the leading end portion 4a of the apply pin 4 is covered by a cover member 21. In the second embodiment, a leading end portion of the apply pin 4 comes into contact through the cover member 21 without being directly brought into contact with the pressure receiving surface 2b of the contact portion 2a.

As shown in FIG. 3, the cover member 21 is formed in a cap shape covering a whole of the leading end portion 4a of the apply pin 4. In the same manner as that of the first embodiment, the cover member may be structured such as to cover only the portion coming into contact with the pressure receiving portion 2b of the apply side bracket in place of the whole of the leading end portion 4a.

In the first and second embodiments mentioned above, a hardness of the cover members 20 and 21 may be equal to a hardness of the apply side bracket 2 and the apply pin 4 of the leading end portion 4a, however, in view of preventing the abrasion of the apply side bracket 2, it is preferable that the cover members 20 and 21 are formed by a material which is harder than the apply pin 4 or the leading end portion 4a. Further, it is preferable that the cover members 20 and 21 are formed by a material which is softer than the apply side bracket 2.

It is preferable that the cover members 20 and 21 are selected from a material which is softer than the apply side bracket 2 and harder than the apply pin 4. Further, in each of the embodiments mentioned above, the single cover member 20 or 21 is provided between the apply side bracket 2 and the apply pin 4, however, a plurality of cover members may be interposed as occasion demands. In this case, a plurality of cover members may be made of the same material or have the same hardness, however, it is possible to laminate a plurality of cover members made of different materials or having different hardness.

In each of the embodiments mentioned above, the apply side bracket 2 and the anchor side bracket 3 are shown as the different shapes, however, may be formed in the same shape. Further, it goes without saying that the present invention can be applied to a brake band having a double strap, in place of the brake band having the single strap shown in FIG. 1.

This application claims priority from Japanese Patent Application No. 2004-321516 filed on Nov. 5, 2004, which is hereby incorporated by reference herein.

Claims

1. A brake band in which a bracket is coupled to an end portion of a curved strap and an apply pin comes into contact with a contact portion of said bracket, thereby generating a fastening force,

wherein an abrasion preventing means is provided between the contact portion of said bracket and said apply pin.

2. A brake band according to claim 1, wherein said abrasion preventing means is constituted by a cover member covering the contact portion of said bracket.

3. A brake band according to claim 2, wherein said cover member is made of a material harder than said apply pin.

4. A brake band according to claim 1, wherein said abrasion preventing means is constituted by a cover member covering a leading end portion of said apply pin.

5. A brake band according to claim 4, wherein said cover member is made of a material softer than said bracket.

6. A brake band according to claim 1, wherein a friction member is provided in an inner periphery of said strap.

7. A brake band according to claim 2, wherein a friction member is provided in an inner periphery of said strap.

8. A brake band according to claim 3, wherein a friction member is provided in an inner periphery of said strap.

9. A brake band according to claim 4, wherein a friction member is provided in an inner periphery of said strap.

10. A brake band according to claim 5, wherein a friction member is provided in an inner periphery of said strap.