JP2012218709A - Brake chamber and boot member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the problem of a strength shortage of a connection portion between a housing and a cylinder caused by the incursion of foreign matter into the housing while suppressing a cost increase in a brake chamber having a configuration where the housing forming a push plate housing space and the cylinder housing a push rod are connected.SOLUTION: The brake chamber 1 includes a rod portion 22 making a piston movement in a cylinder 17 via pressure of compressed air to advance a push rod 2 to a brake device, and a dust boot 29 for preventing the incursion of foreign matter such as mud into the cylinder 17. In the dust boot 29, a seal portion 29c is formed to function so as to prevent incursion of foreign matter into the connection part between a cup 16 and the cylinder 17 by elastically coming into contact with the inner peripheral surface 16b of the cup 16.

Description

  The present invention provides a brake chamber having a rod member for moving a push rod for operating a brake device of a vehicle to the brake device by operating a piston in a cylinder through a pressure of compressed air or a biasing force of a spring. About. The present invention also relates to a boot member that functions to prevent foreign matter from entering the cylinder in the brake chamber.

  For example, in a brake system for a large automobile, an air brake using compressed air supplied from an air compressor as a braking energy source is used. This air brake has a push rod that pushes the brake shoe and a brake chamber for driving the push rod. The brake chamber is deformed by the supply of compressed air and the push rod is turned into the brake shoe. A diaphragm that is pushed toward is provided (for example, see Patent Document 1).

  The brake chamber may be provided with a spring brake chamber that operates as a parking brake in addition to a service brake chamber that brakes wheels with compressed air for braking during vehicle travel. In the spring brake chamber, the spring is compressed and compressed by the pressure of compressed air during non-braking, and the push rod is not pushed, but during braking, the compressed air is released and the pushing force of the spring acts on the push rod. As a result, the brake enters a braking state.

Japanese Patent No. 3710477

  The brake chamber as described above may be provided with a member called a push plate that pushes the push rod. The push plate includes a flange portion that is pushed by a diaphragm that is deformed by supply of compressed air, and a rod portion that pushes the push rod, and the rod portion has a structure in which a piston operates in the cylinder.

  Here, since the housing space of the push plate is enlarged and reduced by deformation of the diaphragm, an opening may be formed in a part of the housing forming the housing space of the diaphragm so that air can be circulated to the outside. In this case, foreign matter such as mud enters the housing from the opening, which may further enter the cylinder and hinder the operation of the push plate. Therefore, there is a case where a dust boot for preventing such foreign matter from entering the cylinder is provided. In this case, one end of the dust boot is attached to the tip of the cylinder, and the other end is attached to the rod portion.

  By the way, when the housing for forming the diaphragm housing space and the above-described cylinder are not integrally formed, but are configured separately and connected to each other, foreign matters such as mud reach the connecting portion. It becomes. For example, when the housing and the cylinder are connected by welding, rust is generated in the welded portion due to moisture contained in the foreign matter, and there is a possibility that the strength of the connected portion is reduced. However, in order to solve such a problem, providing a special foreign matter intrusion prevention means separately increases the cost of the apparatus.

  Accordingly, the present invention has been made in view of such a situation, and an object of the present invention is to provide a brake chamber having a configuration in which a housing that forms a housing space for a push plate and a cylinder that houses a push rod are connected to each other. An object of the present invention is to prevent the problem that the strength of the connecting portion between the housing and the cylinder is insufficient due to the foreign matter entering the inside while suppressing the cost increase.

  In order to solve the above-described problem, the brake chamber according to the first aspect of the present invention is a push that operates a brake device of a vehicle by operating a piston in a cylinder through the pressure of compressed air or the biasing force of a spring. A rod member that advances the rod with respect to the brake device, a diaphragm that presses the rod member by receiving compressed air, and a housing space for the diaphragm are formed, and one end of the cylinder enters inside. A housing that is connected to the cylinder in a state, a boot member that is attached to the cylinder at one end and the rod member at the other end, and functions to prevent entry of foreign matter into the cylinder, The boot member is in contact with the inner peripheral surface of the housing, thereby the housing. Wherein the sealing section acting as to prevent foreign material from entering the connection portion between the cylinder is formed with.

  According to this aspect, the boot member that functions to prevent foreign matter from entering the cylinder has a function to prevent foreign matter from entering the connecting portion between the housing and the cylinder by contacting the inner peripheral surface of the housing. Since the seal portion is formed, means for preventing foreign matter from entering the connecting portion between the housing and the cylinder is configured by attaching the boot member.

  In other words, the boot member that functions to prevent foreign matter from entering the cylinder is used as a means for preventing foreign matter from entering the connecting portion between the housing and the cylinder. It is possible to solve the problem that foreign matter enters the connecting portion with the cylinder and the strength is insufficient.

  According to a second aspect of the present invention, in the first aspect, the second aspect of the present invention is configured to receive a force in a direction in contact with the inner peripheral surface of the housing by pressure from the outside of the seal space.

  According to this aspect, since the seal portion has a configuration that receives a force in a direction in contact with the inner peripheral surface of the housing by pressure from the outside of the seal space, even when the pressure is received from the outside of the seal space, The sealing function is not impaired, and the operational effect of the first aspect can be obtained with certainty.

  According to a third aspect of the present invention, a rod member that causes a push rod that operates a brake device of a vehicle to advance with respect to the brake device by operating a piston in the cylinder through the pressure of compressed air or the biasing force of a spring. A diaphragm that presses the rod member by receiving compressed air and deforms, and a housing that forms a housing space for the diaphragm and that is connected to the cylinder in a state where one end of the cylinder enters inside. The boot chamber is a boot member that is mounted and fixed between one end of the cylinder and the rod member and functions to prevent foreign matter from entering the cylinder, and the boot member includes the housing By contacting the inner peripheral surface of the housing to the connecting portion of the housing and the cylinder. Wherein the sealing section acting as to prevent the intrusion are formed.

  According to this aspect, as described in the first aspect, the boot member functioning to prevent the entry of foreign matter into the cylinder is provided with means for preventing the foreign matter from entering the connecting portion between the housing and the cylinder. As a result, it is possible to solve the problem that the foreign matter enters the connecting portion between the housing and the cylinder and the strength is insufficient while suppressing an increase in cost.

The side sectional view of the brake chamber concerning the present invention. The exploded perspective view of a base. These cross-sectional perspective views of a base, a push plate, and a dust boot. Side sectional drawing of the connection part of a dust boot and a cup and a cylinder. Side sectional view of a connection part of a dust boot and a cup and a cylinder (another embodiment).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below is merely an embodiment of the present invention, and the following embodiment will be described on the assumption that the present invention is not limited.

  1 is a side sectional view of a brake chamber 1 according to the present invention, FIG. 2 is an exploded perspective view of a base 15, FIG. 3 is a sectional perspective view of the base 15, a push plate 20, and a dust boot 29. 4 is a side cross-sectional view of the dust boot 29 and the connection portion between the cup 16 and the cylinder 17. FIG. 5 is a side sectional view of the dust boot 290 and the connection portion between the cup 16 and the cylinder 17 according to another embodiment.

  In FIG. 1, a brake device (not shown) is provided on the right side of the brake chamber 1, and a push rod indicated by reference numeral 2 advances to the brake device, so that a brake shoe included in the brake device is expanded. The braking force is generated.

  The brake chamber 1 includes a service brake unit 13 for a service brake and a spring brake unit 3 for a parking brake. A push rod is formed by either the service brake unit 13 or the spring brake unit 3. 2 is pushed toward the brake device.

  The spring brake unit 3 is provided with housing spaces for the spring 6 and the piston 5 by connecting the housings 4A and 4B. The piston 5 provided in the spring brake part 3 has a flange part 5a and a cylinder part 5b, and the cylinder part 5b is a push plate of the service brake part 13 by a spring 6 provided between the flange part 5a and the housing 4A. It is biased in the direction of pushing 20.

  The internal spaces of the housings 4A and 4B are provided by the flange portion 5a in a space where the spring 6 is provided and a space 10 on the opposite side thereof, and airtightness is prevented so that air does not flow between them. It is kept. Compressed air is supplied to the space 10 from compressed air supply means (not shown), and the spring 6 is compressed by the flange 5a as shown in the figure when not braked due to the pressure. When the parking brake operation is performed, the compressed air in the space 10 is extracted, the urging force of the spring 6 acts, and the piston 5 pushes the push rod 2 through the push plate 20 to enter the brake braking state.

  Next, a release bolt 7 is screwed into a bolt hole 4c provided in the center portion of the housing 4A, and one end of the release bolt 7 enters the cylinder portion 5b of the piston 5. A flange portion 7 a is formed at the tip of the portion of the release bolt 7 that enters the cylinder portion 5 b, and the biasing force of the spring 6 is rotated by rotating the nut 8 fixed to the other end portion of the release bolt 7. The piston 5 can be manually moved in the left direction of the figure, that is, in the brake releasing direction. That is, even when a failure occurs in the compressed air supply circuit, the brake can be manually released.

  On the other hand, in the service brake unit 13, a housing space for the push plate 20 and the diaphragm 19 is provided by the housing 4 </ b> B constituting the spring brake unit 3 and the base 15.

  As an example, the base 15 has a divided structure of a cup 16 as a housing, a cylinder 17, and a flange 18. The flange 18 is welded to one end of the cylinder 17, and the cup 16 is welded to the other end of the cylinder 17. Are integrated.

  More specifically, the connecting portion between the cylinder 17 and the cup 16 is such that the tip portion of the cylinder 17 slightly enters the inside of the cup 16 and both are connected and fixed in this state.

  A diaphragm 19 is sandwiched between the housing 4B and the cup 16, and compressed air is supplied from a compressed air supply port (not shown) between the diaphragm 19 and the housing 4B. . When compressed air is supplied between the diaphragm 19 and the housing 4B, the push rod 2 is pushed through the push plate 20 with the deformation of the diaphragm 19, and the brake is activated.

  The cup 16 is provided with an opening 16a that communicates with the outside so that the internal space 11 of the service brake portion 13 defined by the housing 4B and the cup 16 can be enlarged and reduced following the deformation of the diaphragm 19. Yes. For this reason, foreign matter such as mud and dust enters the internal space 11 from the outside through the opening 16a, and it may enter the cylinder 17 and hinder smooth sliding of the bush member 23 described later.

  Therefore, a dust boot 29 as a boot member is attached and fixed between the cylinder 17 and the rod portion 22 so as to form a dome shape by an elastically deformable material (for example, rubber). The dust boot 29 is elastically formed at one end 29 a in a concave groove 22 a formed along the circumferential direction of the rod portion 22, and at the other end 29 b in a concave groove 17 a formed along the circumferential direction at the tip of the cylinder 17. It is fixed by fitting.

  When the push plate 20 operates as a piston, the distance between the concave groove 22a formed in the rod portion 22 and the concave groove 17a formed in the cylinder 17 changes accordingly, but the dust boot 29 is formed of an elastic material. Therefore, it is elastically deformed following the above deformation of the distance, and the sealing function can be maintained.

  Reference numeral 9 denotes a connecting pipe that communicates the accommodation space of the spring 6 in the spring brake part 3 and the space 11 in the service brake part 13. That is, the accommodation space of the spring 6 in the spring brake part 3 is basically a sealed space in order to prevent deterioration of the spring 6 due to moisture or the like, but the accommodation space of the spring 6 is expanded or contracted by the piston operation of the piston 5. Therefore, the air flow to the accommodation space of the spring 6 is smoothly performed by the connecting pipe 9.

  Next, the push plate 20 includes a flange portion 21 and a rod portion 22 as a rod member. In the present embodiment, the push plate 20 is integrally formed as a whole by forging aluminum, and the weight is reduced. This is an example, and the flange portion 21 and the rod portion 22 can be formed separately and then both can be connected by welding or the like.

  Between the inner periphery of the cylinder 17 and the outer periphery of the rod portion 22, an annular bush 23 is provided. The bush 23 is fixedly attached to the rod portion 22, and piston-operates in the cylinder 17 together with the rod portion 22 while being in sliding contact with the inner periphery of the cylinder 17.

  This bush 23 is for performing the piston operation of the rod portion 22 stably. In this embodiment, the bush 23 is formed of a resin material, and by forming an appropriate clearance with the inner periphery of the cylinder 17, In addition, by securing an appropriate length in the moving direction, the rod portion 22 can be prevented from being inclined (squeezed) with respect to the cylinder 17.

The above is the overall configuration of the brake chamber 1, and the dust boot 29 will be described in further detail below.
In FIG. 4, the dust boot 29 has a concave groove 22 a in which one end 29 a is formed along the circumferential direction of the rod portion 22 and a second end 29 b is formed in the circumferential direction at the tip of the cylinder 17 as described above. Each groove 17a is fixed by being elastically fitted.

  Here, since the cylinder 17 and the cup 16 are connected by welding, when a foreign substance, particularly moisture, enters the connecting portion, rust is generated at the connecting portion, which may cause insufficient strength of the connecting portion. However, in order to solve such a problem, providing a special foreign matter intrusion prevention means separately increases the cost of the apparatus.

  Therefore, in the present invention, the dust boot 29 that functions to prevent the intrusion of foreign matter into the cylinder 17 is elastically contacted with the inner peripheral surface 16b of the cup 16 so that the connection portion between the cup 16 and the cylinder 17 is reached. A seal portion 29c is formed which functions to prevent the entry of foreign matter.

  The seal portion 29c is formed so as to protrude outward over the entire outer periphery of the dust boot 29, and is integrally formed with the dust boot 29 main body and an elastic material (for example, rubber). Accordingly, when the dust boot 29 is attached, the seal portion 29c can elastically contact the inner peripheral surface 16b of the cup 16 without performing any special work.

  Since the seal portion 29c elastically contacts the inner peripheral surface 16b of the cup 16 in this way, entry of foreign matters such as mud from the seal outer space 31 into the seal inner space 30 is prevented. Thus, such a problem that the strength of the connecting portion with 16 is insufficient is prevented.

  In this embodiment, the seal portion 29c is formed integrally with the dust boot 29. However, for example, a ring-shaped member is used as the seal portion 29c, and this is fixed to the dust boot 29 by means such as adhesion. You may do it.

  Further, in the present embodiment, the seal portion 29c is provided at one location with respect to the sealing function exhibiting direction, but a plurality of locations may be provided so that each seal portion elastically contacts the inner peripheral surface 16b of the cup 16. good.

  Further, the seal portion may be an embodiment as shown in FIG. The dust boot 290 shown in FIG. 5 is similar to the dust boot 29 described above. One end 290 a is formed in the recessed groove 22 a formed along the circumferential direction of the rod portion 22, and the other end 290 b is disposed in the circumferential direction at the tip of the cylinder 17. They are fixed by being elastically fitted into the concave grooves 17a formed along the grooves.

  In addition, the dust boot 290, like the dust boot 29 described above, is in contact with the inner peripheral surface 16b of the cup 16, thereby functioning to prevent foreign matter from entering the connecting portion between the cup 16 and the cylinder 17. 290c is formed.

  The seal portion 290c is formed so as to extend slightly longer along the inner peripheral surface 16b of the cup 16 than the seal portion 29c described above, and when this receives pressure from the outer side 31 of the seal space. In addition, the force in the direction in contact with the inner peripheral surface 16b of the cup 16 is further increased. Accordingly, the sealing function can be reliably maintained even when the pressure from the outer side 31 of the sealing space is received.

  As described above, the specific shape of the dust boot, in particular, the seal portion can take various forms, and it goes without saying that these are also included in the scope of the present invention without departing from the spirit of the present invention. .

DESCRIPTION OF SYMBOLS 1 Brake chamber 2 Push rod 3 Spring brake part 4A, 4B Housing 5 Piston 6 Spring 7 Release bolt 8 Nut 9 Connection pipe 13 Service brake part 15 Base 16 Cup 16b Inner peripheral surface 17 Cylinder 18 Flange 19 Diaphragm 20 Push plate 21 Flange part 22 Rod part 23 Bush 29 Dust boot 29c Seal part

Claims (3)

A rod member that advances a push rod for operating a brake device of a vehicle with respect to the brake device by piston-operating in the cylinder via a pressure of compressed air or a biasing force of a spring;
A diaphragm that presses the rod member by receiving and deforming compressed air; and
A housing that forms a housing space for the diaphragm and is connected to the cylinder in a state in which one end of the cylinder enters inside;
One end side is attached to the cylinder, the other end side is attached to the rod member, and a boot member that functions to prevent foreign matter from entering the cylinder, and
The boot member is formed with a seal portion that functions to prevent entry of foreign matter into a connection portion between the housing and the cylinder by contacting the inner peripheral surface of the housing.
Brake chamber characterized by that. The brake chamber according to claim 1, wherein the seal portion receives a force in a direction in contact with the inner peripheral surface of the housing by pressure from outside the seal space.
Brake chamber characterized by that. A rod member that advances a push rod for operating a brake device of a vehicle with respect to the brake device by piston-operating in the cylinder via a pressure of compressed air or a biasing force of a spring;
A diaphragm that presses the rod member by receiving and deforming compressed air; and
In a brake chamber including a housing that forms a housing space for the diaphragm and that is connected to the cylinder with one end of the cylinder entering the inside, the mounting is fixed between the one end of the cylinder and the rod member. A boot member that functions to prevent entry of foreign matter into the cylinder,
The boot member is formed with a seal portion that functions to prevent entry of foreign matter into a connection portion between the housing and the cylinder by contacting the inner peripheral surface of the housing.
A boot member characterized by that.

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