JPH09264348A - Drum brake for mechanical vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a sense of incongruity of an operating feeling by arranging two sets of a pair of brake shoes inside a back plate so that they may be doubly overlapped, and providing a first cam shaft on the back plate side and a second cam shaft so arranged as to project from the outer end of the first cam shaft on the opposite back plate side. SOLUTION: Two sets of brake shoe units 6, 7 are arranged inside a back plate 3 to be covered with a brake drum 2 so as to be doubly overlapped. A mechanism actuator is provided with a cylindrical first cam shaft 14 so arranged as to project outward from one end of a web 5a of the brake shoe unit 6 on the back plate side through the back plate 3, and a small-diameter second cam shaft 15 so arranged as to project from the outer end of the first cam shaft 14 through the inside of the first cam shaft 14 from one end of a web 5a of the brake shoe unit 7 on the opposite back plate side. Therefore, the addition of both braking force is made available, and a sense of congruity of an operating feeling can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a mechanical drum brake used in a traveling vehicle such as a three-wheeled vehicle, a three- or four-wheeled buggy vehicle, a snowmobile, and a golf cart, and more particularly to a multi-input type drum brake that receives input from a plurality of brake systems.

[0002]

2. Description of the Related Art A mechanical vehicle brake in which a pair of brake shoes are expanded and opened by a mechanical actuator is disclosed, for example, in Japanese Utility Model Laid-Open No. 48-106036 and Japanese Patent Laid-Open No. 63-287687. As shown, there is a so-called multi-input type in which a plurality of brake systems are connected to one drum brake. The former drum brake is shown in which two wire cables are connected to the tip side of the brake arm fixed to the expansion actuator inside the back plate, and the latter drum brake has a pair of brake shoes. Two brake arms, in which a cam member serving as an expanding actuator is provided between one ends, and an anchor pin is provided between the other ends of the brake shoes, and a cam shaft fixed to the cam member is operated by a wire cable. A leading and trailing type that rotates by one or both of the above, and a cam member as an actuator for expansion between the one end and the other end of the pair of brake shoes, and each cam member is provided. A dual 2 leading type in which a wire cable is connected to the tip of the brake arm that is pivotally supported is shown. Cage, in a multi-input type drum brake Any of these two systems, by two systems one of the brake operation element such as a brake pedal or brake lever, and to allow actuation of the drum brake.

[0003]

However, in the former reading and trailing type of the former and the latter,
When one of the brake operating elements is operated, the other wire cable is loosened, and the other brake operating element connected to this wire cable has a problem of playing in a free state. When operated, the play stroke becomes large and the operation feeling is degraded. Further, when operating both brake operators back and forth, it is not possible to add both brake forces unless the brake operator that follows is operated with a greater force than the previous brake operator. Further, in the former drum brake, the initial input value of the latter brake operator changes for each braking depending on the magnitude of the braking force input by the former brake operator, and the operation feeling of both brake operators is increased. It will give the ring a feeling of strangeness.

Further, in the latter dual 2 reading type, since two brake arms project to the outside of the back plate while facing each other by 180 degrees, they occupy a large installation space on the vehicle body and the wiring of the wire cable is long. Then, especially in small displacement vehicles such as soft bikes and scooters using small diameter tires, it was extremely difficult to fit this type of drum brake in a small wheel.

The present invention has been made in view of the above circumstances, and an object of the present invention is not to cause deterioration of operation feeling and discomfort, and addition of braking force by two brake operating elements. An object of the present invention is to provide a compact drum brake for a mechanical vehicle, which is easy to occupy, occupies little space, and can be easily accommodated in a small-diameter wheel.

[0006]

According to the present invention, in accordance with the above-mentioned object, a mechanical actuator for expanding is arranged between one ends of a pair of arcuate brake shoes arranged to face each other inside a back plate. An anchor serving as an expansion fulcrum is arranged between the other ends of the brake shoes, and the mechanical actuator is operated by operating one or both of two brake operating elements to move the brake shoe to the anchor. In a drum brake for a mechanical vehicle that expands to a fulcrum, in the mechanical actuator, two sets of the pair of brake shoes are arranged in a double stack inside the back plate, and in the mechanical actuator, A cylindrical first cam shaft that is disposed so as to project outward through the back plate from between one ends of the brake shoes on the back plate side, and an anti-back puck. A second cam shaft penetrating the inside of the first cam shaft from one end portion of the brake shoe on the side of the door and projecting from the outer end of the first cam shaft; A first cam portion that supports one end portion of the brake shoe on the back plate side is provided at the end, and the outer end of the first cam shaft is rotated by pulling a first connecting means such as a wire cable or a rod. A first brake arm is fixed, and a second cam portion that supports one end portion of the brake shoe on the side opposite to the back plate is provided at the inner end of the second cam shaft, and a wire is provided at the outer end of the second cam shaft. It is characterized in that a second brake arm which is rotated by pulling a second connecting means such as a cable or a rod is fixed.

With this structure, the drum brake has two
The system is a multi-input brake in which the systems are combined, and the pair of brake shoes of each system operate independently without causing a nuisance operation to the components of the other system by the traction of the respective connecting means. Further, when the first and second brake arms are rotated by pulling both connecting means, the added braking force by the two pairs of brake shoes acts.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A drum brake for a mechanical vehicle according to the present invention will be described below with reference to an embodiment shown in the drawings. The drum brake 1 is a two-system multi-input type drum brake that is operated by either or both of two brake operating elements such as a brake pedal and a brake lever. Inside the back plate 3 covered with the brake drum 2, Two pairs of brake shoe units 6 and 7 formed by a combination of a pair of leading brake shoes 4 and trailing brake shoes 5 facing each other are arranged in a double stack.

The brake shoes 4, 5 of the brake shoe units 6, 7 are fixed perpendicularly to the above-mentioned webs 4a, 5a arranged parallel to the back plate 3 and the arc surfaces of the outer peripheries of the webs 4a, 5a. Rim 4b, 5b to be provided, and strip-shaped lining 4 attached to the outer peripheral surface of the rim 4b, 5b
It consists of c and 5c. A mechanical actuator 8 and an anchor pin 9 are provided on the back plate 3 at positions orthogonal to the brake shoes 4, 5, and the brake shoes 4, 5 of the first brake shoe unit 6 on the back plate side are , One end portions 4d and 5d of the respective webs 4a and 5a are attached to the first cam portion 10 of the actuator 8,
In the brake shoes 4, 5 of the second brake shoe unit 7 on the side opposite to the back plate, one ends 4d, 5d of the webs 4a, 5a are similarly supported by the second cam portion 11 of the actuator 8, respectively, and further both units 6 The other ends 4e, 5e of the four webs 4a, 5a of No. 7, 7 are supported by the anchor pin 9, respectively.

The shoe return spring 1 is attached to the webs 4a and 5a of the brake shoe units 6 and 7, respectively.
2 and 13 are stretched, and the opposing brake shoes 4 and 5 are always urged by the shoe return springs 12 and 13 in the diameter reducing direction.

The mechanical actuator 8 includes the webs 4a, 5 of the brake shoe unit 6 on the back plate side.
a cylindrical first cam shaft 14 which is disposed so as to project outward through the back plate 3 from between the one end portions 4d and 5d of a and one end of the webs 4a and 5a of the brake shoe unit 7 on the side opposite to the back plate. The first cam shaft 14 from between the portions 4d and 5d.
Has a small diameter second cam shaft 15 which penetrates the inside of the first cam shaft 14 and projects from the outer end of the first cam shaft 14. First
The two chamfered first and second cam portions 10 and 11 are integrally provided at the inner ends of the second cam shafts 14 and 15, and the bases of the first and second brake arms 16 and 17 are provided at the outer ends. The ends are fixed using connecting bolts 18.

The flat portion 10 of the first and second cam portions 10 and 11
One ends 4d, 5d of the webs 4a, 5a of the brake shoe units 6, 7 which are urged in the diameter reducing direction by the pulling forces of the shoe return springs 12, 13 are supported by the a, 10a, 11a, 11a. Further, first and second connecting means 19, 20 using wire cables are connected to the tips of the first and second brake arms 16, 17.

The tip ends of the connecting means 19 and 20 are individually connected to two brake operating elements such as a brake pedal and a brake lever (not shown). When the first connecting means 19 is pulled by the brake operating element, The first brake arm 16 rotates, and at the same time, the first cam portion 10 and the first cam shaft 14
Rotate integrally with each other, the brake shoes 4, 5 of the first brake shoe unit 6 are expanded, and the linings 4c, 5
A braking action is performed by sliding c on the inner peripheral surface of the brake drum 2. Further, when the second connecting means 20 is pulled by the brake operator, the second brake arm 17 rotates, and at the same time, the second cam portion 11 and the second cam shaft 15 rotate integrally, and the second The brake shoes 4, 5 of the brake shoe unit 7 are expanded and the linings 4c, 5c are brought into sliding contact with the inner peripheral surface of the brake drum 2 to perform a braking action.

When the brake arms 16 and 17 are individually operated as described above, only the constituent members of the respective brake systems are operated, and the constituent members of the other brake system are not operated. When both the first and second brake arms 16 and 17 are rotated,
The expansion operation by the second cam shafts 14 and 15 is performed without interfering with each other, and the brake drum 2 has the first and second expansion operations.
The cam portions 10 and 11 act by adding forces that push and spread the brake shoes 4 and 5 of the brake shoe units 6 and 7.

As described above, the drum brake 1 of this embodiment is a brake system that uses the first brake arm 16 and the first cam shaft 14, and a brake system that uses the second brake arm 17 and the second cam shaft 15. Since the systems are configured separately so that each brake system operates independently, if each brake system is operated with individual operating force,
Both braking forces can be effectively added to stop the brake drum 2 with a high braking force. Furthermore, compared to the conventional method of operating a pair of brake shoes with two brake operating elements, even if the operation of the two brake operating elements is changed, the operation input of both brake operating elements is changed due to the change in the initial input value. Since the ring does not feel uncomfortable and one brake system does not give a mischievous operation to the other brake system, there is also a problem that the other brake operator is made to play and the operation feeling is deteriorated. It can be resolved.

Further, since the first and second cam shafts 14 and 15 are coaxially arranged and the first and second brake arms 16 and 17 are fixed to the cam shafts 14 and 15 in the same direction, they are fixed. The handling of the first and second connecting means 19, 20 can be performed satisfactorily as in the case of the single brake system, and the drum brake 1 can be formed in a compact size with a small occupied area. It can be sufficiently applied to a small wheel of a small displacement vehicle such as a scooter.

[0017]

As described above, the drum brake for a mechanical type vehicle of the present invention has two sets of a pair of brake shoes arranged in a double stack inside a back plate, and a mechanical actuator and a back plate. The cylindrical first cam shaft penetrating the back plate from one end of the brake shoe on the side of the rear side and projecting outward, and the inside of the first cam shaft from the one end of the brake shoe on the side opposite to the back plate. A second cam shaft penetrating therethrough, the second cam shaft projecting from the outer end of the first cam shaft, and an inner end of the first cam shaft supporting one end of the brake shoe on the back plate side. A cam portion is provided, and a first brake arm that is rotated by pulling a first connecting means such as a wire cable or a rod is fixed to the outer end of the first cam shaft, and the inner end of the second cam shaft is The back plate side A second cam portion that supports one end of the brake shoe is provided, and a second brake arm that is rotated by pulling a second connecting means such as a wire cable or a rod is fixed to the outer end of the second cam shaft. Since the brake system using the first brake arm and the first cam shaft and the brake system using the second brake arm and the second cam shaft are separately configured, each brake system operates independently, and each brake system operates. When the systems are operated with individual operating forces, both braking forces can be effectively added to stop the brake drum with a high braking force. Furthermore, compared to the conventional method of operating a pair of brake shoes with two brake operating elements, even if the operation of the two brake operating elements is changed, the operation input of both brake operating elements is changed due to the change in the initial input value. Since the ring does not feel uncomfortable and one brake system does not give a mischievous operation to the other brake system, there is also a problem that the other brake operator is made to play and the operation feeling is deteriorated. It can be resolved.

Furthermore, since the first and second brake arms can be aligned and fixed to the first and second cam shafts arranged coaxially in the same direction, the wire cable can be handled in a single brake system. Not only can it be performed satisfactorily as in the case above, but since the drum brake can be formed in a small size that occupies a small area, it can be adequately applied to small wheels of small displacement vehicles such as soft bikes and scooters. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along a line II of FIG. 2 showing one embodiment of the present invention;

FIG. 2 is a front view of a drum brake showing one embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1, showing one embodiment of the present invention;

FIG. 4 is an exploded perspective view of a first cam shaft and a second cam shaft showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Drum brake 2 ... Brake drum 3 ... Back plate 4 ... Leading brake shoe 5 ... Trailing brake shoe 4a, 5a ... Web 4b, 5b ... Rim 4c, 5c ... Lining 4d, 5d ... Web 4a, 5a One end 4e, 5e of the web 4a, the other end of the web 5a 6, 7 ... Brake shoe unit composed of a combination of the brake shoes 4, 5 ... Mechanical actuator 9 ... Anchor pin 10 ... First cam portion 11 ... 2nd cam part 10a, 11a ... The plane part of the 1st, 2nd cam parts 10, 11 14 ... 1st cam shaft 15 ... 2nd cam shaft 16 ... 1st brake arm 17 ... 2nd brake arm 19 ... Wire cable First connecting means used 20 ... Second connecting means using wire cable

Claims (1)

[Claims] 1. A mechanical actuator for expansion is arranged between one ends of a pair of arcuate brake shoes arranged to face each other inside a back plate, and an expansion fulcrum is provided between the other ends of the brake shoes. A drum brake for a mechanical vehicle in which an anchor is provided and the mechanical actuator is operated by operating one or both of two brake operating elements to expand the brake shoe with the anchor as a fulcrum. , The mechanical actuator has two sets of the pair of brake shoes arranged in a double stack inside the back plate, and the mechanical actuator has a back plate from one end of the brake shoe on the back plate side. The first cam shaft having a cylindrical shape penetrating through the outer periphery of the brake shoe and the one end of the brake shoe on the side opposite to the back plate. A second cam shaft penetrating the inside of the shaft and protrudingly arranged from the outer end of the first cam shaft, and one end of the brake shoe on the back plate side at the inner end of the first cam shaft. While providing the first cam portion to support,
At the outer end of the first cam shaft, a wire cable, rod, etc.
A first brake arm that rotates by pulling the connecting means is fixed, and a second cam portion that supports one end portion of the brake shoe on the side opposite to the back plate is provided at the inner end of the second cam shaft. A drum brake for a mechanical vehicle, characterized in that a second brake arm that is rotated by pulling a second connecting means such as a wire cable or a rod is fixed to the outer end of the two-cam shaft.