JP3938236B2 - Wedge brake sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rainwater and washing water from entering by providing an air vent on a part opposed to a part of a member provided adjacently to a brake cylinder on the horizontal side surface of a boot and providing a shielding wall in which the side of the member provided adjacently to the brake cylinder and the side of the brake cylinder are opened. SOLUTION: On a base end part of a cylindrical part 20 of a boot 17a, an air vent communicating the inside and outside of the boot 17a is formed. On a part surrounding the air vent on the horizontal side surface of the cylindrical part 20, a substantially V-shaped shielding wall 23 is provided. The shielding wall 23 is projected from the horizontal side surface of the cylindrical part 20 toward the inner peripheral surface of a peripheral wall part 22 and is opened to the sides of the peripheral wall part 22 and a brake cylinder 3a. By this constitution, rainwater raised by a wheel at the time of a traveling in rainwater or washing water sprayed at the time of using a high pressure car washing machine can be effectively prevented from entering within the boot 17a. Therefore, improvement of durability of a wedge brake and a drum brake into which the wedge brake is incorporated is contrived.

Description

[0001]
BACKGROUND OF THE INVENTION
The wedge brake sealing device according to the present invention is attached to a wedge brake used as a parking brake of a large automobile, and prevents foreign substances such as rainwater from entering the brake cylinder.
[0002]
[Prior art]
2. Description of the Related Art As a parking brake for trucks, buses, and the like, a wedge brake that generates a braking force by mechanically pushing a brake piston in a brake cylinder (wheel cylinder) provided on a wheel portion with a wedge has been widely used. 8 to 9 show a wedge brake with a sealing device described in Japanese Patent No. 2598765. A pair of brake shoe assemblies 2, 2 are supported on the front surface of the backing plate 1 that is supported by the suspension and does not rotate, so that it can be slightly displaced over the diameter direction of the backing plate 1. Brake cylinders 3a and 3b are supported and fixed at positions between the two opposite sides of the backing plate 1 in the diametrical direction between the brake shoe assemblies 2 and 2 in the circumferential direction. Then, both circumferential edges of the webs 4 and 4 constituting the brake shoe assemblies 2 and 2 are engaged with the outer ends of the pistons 5 and 5 constituting the brake cylinders 3a and 3b. Yes. The brake shoe assemblies 2 and 2 are provided with elastic force directed toward the inside in the diameter direction of the backing plate 1 by return springs 6 and 6.
[0003]
Further, a wedge 7 as shown in FIG. 9 is incorporated in one brake cylinder 3a (left side in FIG. 8), and the distance between a pair of pistons 5 and 5 constituting the brake cylinder 3a is determined mechanically. It can be expanded freely. For this purpose, a secondary cylinder cylinder 9 is provided on the side surface of the intermediate portion of the cylinder cylinder 8 constituting the brake cylinder 3a, and the wedge 7 is mounted on the slider 10 fitted in the auxiliary cylinder cylinder 9 so as to be displaceable in the axial direction. The base of the. Rollers 12 and 12 are sandwiched between both surfaces of the wedge 7 and the base end surfaces of the pair of pistons 5 and 5, respectively. Based on the engagement between both surfaces of the wedge 7 and the rollers 12, 12 and the base end surfaces of the pistons 5, 5, the pair of pistons 5, 5 pulls out the wedge 7 from the cylinder cylinder 8 (FIG. 9). The more they are displaced in the right direction, the more they move away from each other. In order to displace the wedge 7 in this way, the end portion of the rod 13 fixed to the slider 10 is coupled to an output portion of an actuator (not shown). The actuator includes, for example, a compression spring and a diaphragm. When the pressure chamber is opened to the atmosphere, the rod 13 is pulled to the right in FIG. 9 by the elasticity of the compression spring, and compressed air is fed into the pressure chamber. In this state, the rod 13 is pushed to the left in FIG. 9 against the elasticity of the compression spring.
[0004]
Each of the pistons 5 and 5 includes an inner half 14 and an outer half 15 that are oil-tightly fitted to the cylinder cylinder 8. When a service brake for stopping or decelerating a traveling vehicle is operated, pressure oil is fed into a portion between the inner half portion 14 and the outer half portion 15 inside the cylinder cylinder 8, and the pistons 5. 5 are pushed out from the cylinder cylinder 8. The two brake shoe assemblies 2 and 2 are pushed outward in the diameter direction of the backing plate 1, and the brake linings 16 and 16 constituting the brake shoe assemblies 2 and 2 are rotated together with wheels. Press on the inner peripheral surface of. On the other hand, when the parking brake is operated, the rod 13 is displaced in the direction of pulling out from the cylinder cylinder 8 by an actuator (not shown), and the pair of pistons 5 and 5 are displaced in directions away from each other. As a result, the brake linings 16 and 16 can be pressed against the inner peripheral surface of the drum in the same manner as in the service brake operation described above to exert a braking force.
[0005]
The drum brake with a wedge brake as described above needs to be provided with a sealing device for preventing foreign substances such as rainwater from entering the cylinder cylinder 8 through the sub cylinder cylinder 9. Further, it is necessary to displace the slider 10 and the rod 13 in the sub cylinder cylinder 9 and to project the rod 13 from the sub cylinder cylinder 9. For this reason, conventionally, as the above-mentioned sealing device, a stretchable boot 17 made of an elastic material such as rubber or other elastomer is used. One end (the left end in FIG. 9) of such a boot 17 is engaged with the outer peripheral surface of the sub-cylinder cylinder 9, and the other end (the right end in FIG. 9) is engaged with the outer peripheral surface of the rod 13. By stopping, foreign matter does not enter the sub cylinder cylinder 9 regardless of the displacement of the rod 13 in the axial direction (left and right direction in FIG. 9).
[0006]
By the way, the internal volume of the boot 17 as described above increases and decreases as the rod 13 expands and contracts due to the axial displacement. Therefore, if the inside of the boot 17 is not communicated with the atmosphere, the force required to expand and contract the boot 17 increases. Therefore, conventionally, a vent hole 18 (see FIG. 10 described below) is formed in a part of the boot 17 to prevent the pressure in the boot 17 from rising and falling. In order to prevent foreign matter from entering the boot 17 through the vent hole 18, the Japanese Patent No. 2598765 provides the vent hole 18 on the lower surface of the end portion of the boot 17 so as to face the ground. In addition, there is described a structure in which a cylindrical wall 19 as shown in FIG. 10 is suspended at a position surrounding the vent hole 18 on the lower surface of the end of the boot 17.
[0007]
[Problems to be solved by the invention]
In the case of the wedge brake sealing device described in Japanese Patent No. 2598765 as shown in FIG. Enough to prevent entry into However, when water is sprayed vigorously toward the lower surface of the boot 17 as in the case where the undercarriage of the automobile is washed with a high-pressure car washer, there is a possibility that this water cannot be sufficiently prevented from entering the boot 17. There is.
In view of such circumstances, the wedge brake seal device of the present invention realizes a structure that can sufficiently prevent rainwater from entering during rainy weather driving as well as preventing washing water from entering when using a high-pressure car wash machine. Invented as much as possible.
[0008]
[Means for Solving the Problems]
The wedge brake sealing device according to the present invention is similar to the wedge brake sealing device described above, and the wedge fixed to the rod end and inserted into the brake cylinder is displaced in a direction perpendicular to the axial direction of the brake cylinder. A wedge brake that brakes and releases it, an elastic boot made of elastic material provided between the outer peripheral surface of the rod and the brake cylinder, and a part of the boot. A vent hole for communicating the inside and outside of the boot.
In particular, in the wedge brake sealing device of the present invention, the vent hole is provided in a portion facing a part of a member provided adjacent to the brake cylinder on the lateral side surface of the boot. Further, a shielding wall is provided in a portion surrounding the vent hole on the lateral side surface of the boot, and a member side provided adjacent to the brake cylinder and the brake cylinder side are opened.
[0009]
[Action]
According to the wedge brake sealing device of the present invention configured as described above, the rain water that the wheel rolls up in rainy weather or the cleaning water sprayed when using the high-pressure car wash machine is provided adjacent to the brake cylinder. Is blocked by a part of and a shielding wall. Therefore, the momentum of the rain water or the washing water reaching the periphery of the vent hole provided in the portion facing the part of the member on the lateral side surface of the boot (the surface present in the vertical direction in the assembled state to the vehicle). Becomes weaker. Since this ventilation hole is provided on the lateral side surface of the boot, the rain water or washing water that has reached the vicinity of the ventilation hole without any particular force flows down the lateral side of the boot as it is. It is discharged to the ground. Therefore, it is possible to effectively prevent foreign matters such as rainwater from entering the boot through the vent hole, thereby improving the durability of the wedge brake.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 show an example of an embodiment of the present invention. The structure and operation of the wedge brake for assembling the seal device of the present invention are the same as those of conventionally known wedge brakes including those shown in FIGS. 8 to 9 described above. The description will focus on the features of the present invention. An elastic material is provided between the outer peripheral surface of the rod 13 for displacing the wedge 7 (FIG. 9) in the direction perpendicular to the axial direction of the brake cylinder 3a and the outer peripheral surface of the sub cylinder cylinder 9 constituting the brake cylinder 3a. A boot 17a that is made of an elastic material is provided. This boot 17a has a cylindrical portion 20 in the base half (the half on the brake cylinder 3a side, the lower half in FIG. 1, the left half in FIGS. 3, 4 and 6) and the front half (from the brake cylinder 3a). A bellows portion 21 is provided in each half of the far side in the upper half of FIG. 1 and the right half of FIGS. Such a boot 17a can be extended and contracted by elastically deforming the bellows portion 21. Further, of such a boot 17a, the base end portion of the cylindrical portion 20 (the end portion on the brake cylinder 3a side, the lower end portion in FIG. 1, the left end portion in FIGS. 3, 4 and 6) has the boot 17a. A ventilation hole 18 is formed to allow communication between the inside and outside.
[0011]
The vent hole 18 is a lateral side surface of the cylindrical portion 20 constituting the boot 17a (a surface existing in a substantially vertical direction when mounted on the vehicle) and faces a part of a member provided adjacent to the brake cylinder 3a. It is provided in the part to do. In the case of the illustrated example, the inner peripheral surface of the cylindrical peripheral wall portion 22 formed on the outer peripheral edge portion of the backing plate 1a for constituting a drum brake with a wedge brake is made to face and oppose. Further, a substantially V-shaped shielding wall 23 is provided in a portion surrounding the vent hole 18 on the lateral side surface of the cylindrical portion 20. The shielding wall 23 protrudes from the lateral side surface of the cylindrical portion 20 toward the inner peripheral surface of the peripheral wall portion 22, and the peripheral wall portion 22 side and the brake cylinder 3a side are open. Further, in the illustrated example, a concave groove 24 is formed in a portion of the lateral side surface of the cylindrical portion 20 surrounding the vent hole 18 where the shielding wall 23 is not provided. The concave groove 24 is formed in the outer peripheral edge portion of the end face of the cylindrical portion 20 so as to reach from the one end edge of the shielding wall 23 to the other end edge.
[0012]
According to the wedge brake sealing device of the present invention configured as described above, it is possible to effectively prevent rain water that the wheel rolls up in rainy weather or cleaning water sprayed when using a high-pressure car wash machine from entering the boot 17a. it can. According to the structure of the present invention, the rain water and the washing water (hereinafter referred to as “rain water”) are blocked by the peripheral wall portion 22 and the shielding wall 23 and directly reach the opening portion of the vent hole 18. Absent. In other words, the rainwater or the like is changed in the traveling direction by the peripheral wall portion 22 and the shielding wall 23 until reaching the periphery of the opening portion of the vent hole 18, and the momentum is weakened. In this way, the momentum of rainwater or the like reaching the periphery of the opening of the vent hole 18 is weakened. Moreover, the vent hole 18 is provided on the lateral side surface of the boot 17a. In other words, since the opening portion of the vent hole 18 is present on the lateral side surface that exists in a substantially vertical direction, the rainwater or the like that has reached the vicinity of the opening portion of the vent hole 18 without any particular force is left as it is. The boot 17a flows down the side surface and is discharged to the ground. That is, the shielding wall 23 surrounding the opening of the vent hole 18 has a substantially V shape with the backing plate 1a opened, so even if rainwater or the like enters the shielding wall 23, the rainwater or the like is not shielded. It is efficiently discharged through the discontinuous portion of the wall 23 and does not enter the boot 17 a through the vent hole 18.
[0013]
Furthermore, in the case of the illustrated example, the concave groove 24 is formed in the outer peripheral edge of the cylindrical portion 20, which is a discontinuous portion of the shielding wall 23, from one end edge to the other end edge of the shielding wall 23. Since it forms in the state which reaches | attains, the rain water etc. which flowed down the side surface of the said cylindrical part 20 do not enter into the said vent hole 18 side. Therefore, the amount of rainwater or the like entering the shielding wall 23 can be reduced. By these actions, it is possible to effectively prevent foreign matter from entering the boot 17a through the vent hole 18, and to improve the durability of the wedge brake and the drum brake incorporating the wedge brake. Since the inside diameter of the vent hole 18 is very small, the rain water or the like does not enter the boot 17a only when rain water or the like reaches the opening of the vent hole 18. Rainwater or the like enters the boot 17 a through the vent hole 18 when rainwater or the like is blown into the opening portion of the vent hole 18 or rainwater or the like exists in the opening portion of the vent hole 18. Only when the rod 13 is pulled to extend the boot 17a and the outside air is sucked into the boot 17a through the vent hole 18 in order to operate the parking brake.
[0014]
In the illustrated example, the peripheral wall portion 22 of the backing plate 1a is used as a portion facing a part of a member provided adjacent to the brake cylinder 3a. However, as this portion, such a peripheral wall portion is used. In addition to 22, an accelerator housing supported on the vehicle side (a tubular member through which the rear axle is inserted) or the like can also be used. For example, when an accelerator housing is used, the vent hole 18 and the shielding wall 23 are rotated in the direction in which the boot 17a is rotated 180 degrees (180 degrees with the central axis of the rod 13 as the rotation center) from the state shown in FIG. Place.
[0015]
【The invention's effect】
Since the wedge brake sealing device of the present invention is constructed and operates as described above, it is sufficient to prevent rainwater from entering during rainy weather driving and also to prevent washing water from entering when using a high-pressure car wash machine. Thus, it is possible to improve the durability of the wedge brake and the drum brake incorporating the wedge brake.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an example of an embodiment of the present invention.
FIG. 2 is a perspective view of a boot as viewed from the side.
FIG. 3 is a side view of the same.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is an enlarged BB cross-sectional view of FIG. 4;
FIG. 6 is a plan view of the boot viewed from the upper surface side.
7 is a view from the left side of FIG. 6;
FIG. 8 is a side view showing an example of a drum brake incorporating a wedge brake.
9 is an enlarged cross-sectional view taken along the line CC of FIG.
10A and 10B show boots constituting a conventional sealing device, in which FIG. 10A is a view seen from the left side of FIG. 9, FIG. 10B is a view seen from the right side of FIG. The figure which looked at a part from the lower part of (A).
[Explanation of symbols]
1, 1a Backing plate 2 Brake shoe assembly 3a, 3b Brake cylinder 4 Web 5 Piston 6 Return spring 7 Wedge 8 Cylinder cylinder 9 Sub cylinder cylinder 10 Slider 12 Roller 13 Rod 14 Inner half 15 Outer half 16 Brake lining 17, 17a Boot 18 Ventilation hole 19 Cylindrical wall 20 Cylindrical part 21 Bellows part 22 Peripheral wall part 23 Shielding wall 24 Concave groove

Claims (3)

A wedge brake that is braked and released by displacing a wedge fixed to the tip of the rod and inserted into the brake cylinder in a direction perpendicular to the axial direction of the brake cylinder, the outer peripheral surface of the rod, and the above In a wedge brake seal device provided with an elastic material made of a stretchable boot provided between the brake cylinder and a vent hole provided in a part of the boot to communicate the inside and outside of the boot, The vent hole is provided in a portion facing a part of a member provided adjacent to the brake cylinder on a lateral side surface of the boot, and a portion surrounding the vent hole on the lateral side surface of the boot is provided on the brake. For wedge brakes, characterized in that a shielding wall is provided in which the member side provided adjacent to the cylinder and the brake cylinder side are open. Lumpur apparatus. The concave groove is formed in a portion of the lateral side surface of the boot that surrounds the vent hole and is not provided with a shielding wall so as to reach from one end edge to the other end edge of the shielding wall. The wedge brake seal device described. The wedge brake sealing device according to claim 1, wherein the member provided adjacent to the brake cylinder is a backing plate, and the vent hole is provided in a portion facing a part of the peripheral wall portion constituting the backing plate. .

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