JPH0540075U - Booster - Google Patents

Abstract

(57) [Summary] [Structure] The output shaft 1 is provided in the cylindrical portion 12a of the retainer 12.
The first base 11a is fitted, and the reaction disk 10 is press-fitted into the output shaft 11 at a position adjacent to the base 11a. The tubular portion 12 of the retainer 12 in this state
The rear end of a is fitted into the annular protrusion 2b of the valve body 2. An O-ring 14 is attached between the cylindrical portion 12a and the annular protrusion 2b of the valve body 2. [Effect] Even if the airtightness between the rear end surface 10a of the reaction disk 10 and the tip surface of the annular projection 2b becomes incomplete, the inner peripheral surface of the cylindrical portion 12a of the retainer 12 and the reaction disk that adheres to it Through the outer peripheral portion of 10 and the O-ring 14, the through hole 2 of the valve body 2 is formed.
Atmosphere does not leak from a toward the constant pressure chamber A.

Description

[Detailed description of the device] [Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster, and more particularly, to a sealing means for maintaining airtightness between a reaction disc and an end surface of a valve body.

[Prior Art]

 Conventionally, as a booster, a valve body slidably provided in a shell, a valve plunger that constitutes a part of a valve mechanism, and is slidably fitted in a through hole formed in the valve body, A reaction disc with the front end of the through hole being interposed between the end face of the valve body that opens and the base of the output shaft, and the rear end face of which faces the front end face of the valve plunger, and a bottomed cylinder. And a retainer for holding the base portion of the output shaft and the reaction disc in the tubular portion thereof and for holding the rear end of the tubular portion in pressure contact with the end surface of the valve body. Is known.

[Problems to be solved by the device]

 In the conventional booster described above, the rear end surface of the reaction disc is brought into contact with the end surface of the valve body to close the front end portion of the through hole, and thereby the reaction disc. Airtightness is maintained between the rear end face of the and the end face of the valve body. However, as described above, if the rear end face of the reaction disc is simply brought into contact with the end face of the valve body to close it, airtightness may leak from the abutting portions of both members. Particularly, in the case where a protrusion is formed on the shaft portion of the tip surface of the valve plunger, the tip of the protrusion of the valve plunger is slightly attached to the reaction disc when the brake reaction force at the initial operation of the booster is not substantially transmitted. However, there is a drawback in that the airtightness between the rear end face of the reaction disc and the end face of the valve body easily leaks when it comes into contact with.

[Means for Solving the Problems]

 In view of such circumstances, the present invention provides a valve body that is slidably provided in a shell and a valve mechanism that constitutes a part of a valve mechanism and is slidably fitted in a through hole formed in the valve body. A reaction disc, which is interposed between the plunger and the end face of the valve body where the front end of the through hole opens and the base of the output shaft, and whose rear end face is opposed to the front end face of the valve plunger. It is formed in a cylindrical shape with a bottom, and the base portion of the output shaft and the reaction disc are housed and held in the cylindrical portion, and the rear end of the cylindrical portion is pressed against the end surface of the valve body. In a booster including a retainer, the reaction disc is press-fitted into a tubular portion of the retainer, and the outer peripheral portion of the reaction disc and the tubular portion of the retainer in close contact with the outer peripheral portion of the reaction disc. It holds the airtight between, is provided with a sealing member for holding airtightness between the end face of the rear end portion abutting the valve body to that of the cylindrical portion of the retainer.

[Action]

 With such a configuration, even if the airtightness between the rear end surface of the reaction disc and the end surface of the valve body is incomplete, the tubular portion of the retainer and the outer peripheral portion of the reaction disc and the above The seal member can reliably prevent airtight leakage between the reaction disc and the valve body.

【Example】

 The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, a stepped cylindrical valve body 2 is slidably provided in a shell 1 of a tandem brake booster and two constant pressure chambers A are provided. , C and two transformer rooms B, D are defined. A conventionally well-known valve mechanism 3 is provided in the valve body 2, and a fluid circuit between the chambers A, C, B and D and the pressure passage 4 formed in the valve body 2 is provided by the valve mechanism 3. I am trying to switch. The valve mechanism 3 includes an annular first valve seat 5 formed on the valve body 2, a second valve seat 7 formed on the rear end of the valve plunger 6, and a valve seated on both valve seats 5, 7. It is composed of body 8. The valve plunger 6 is slidably fitted in a through hole 2a formed in the valve body 2, and the tip end portion of the input shaft 9 is connected to the rear end portion of the valve plunger 6. The front end surface 6a of the valve plunger 6 is a tapered surface whose shaft portion bulges toward the front side, and the front end surface 6a faces the rear end surface 10a of the reaction disc 10. The reaction disk 10 is made of disc-shaped rubber, and the rear end surface 10a thereof is superposed on the front end surface of the annular projection 2b having the front end portion of the through hole 2a opened so that the through hole 2a is closed. There is. A large-diameter base portion 11a of the output shaft 11 is in contact with the front end surface 10b of the reaction disc 10, and the base portion 11a of the output shaft 11 and the reaction disc 10 in this state are attached to a bottomed cylindrical retainer. It is accommodated and held in the inside 12. That is, at the front end of the tubular portion 12a of the retainer 12, there is formed a flange-shaped retaining portion 12b that faces radially inward, and the output shaft is provided in a through hole of the retaining portion 12b. The small diameter portion 11 is penetrated to locate the base portion 11a in the tubular portion 12a, thereby preventing the base portion 11a from falling off. Further, the rear side end of the tubular portion 12a of the retainer 12 is a flange-shaped contact portion 12c which is directed outward in the radial direction, and this contact portion 12c is attached to the annular projection 2b by the return spring 13. It is brought into pressure contact with the adjacent step end face 2c. Further, in the non-illustrated operating state, the first valve seat 5 is separated from the valve body 8 while the valve body 8 is seated on the second valve seat 7, and the rear end surface 10a of the reaction disc 10 is A slight gap is maintained between the tip surface 6a of the valve plunger 6. Therefore, the constant pressure chambers A and C and the variable pressure chambers B and D are communicated with each other, and negative pressure is introduced into the respective chambers, while the atmosphere in the pressure passage 4 has the second valve seat 7 and the valve body. The seats of No. 8 and No. 8 prevent the introduction into the transformer rooms B and D. The above-mentioned configuration and the operation based on it are the same as those conventionally known. Therefore, in this embodiment, the inner diameter of the cylindrical portion 12a of the retainer 12 is set to have the same size in the entire axial direction and the outer diameter of the annular projection 2b of the valve body 2. The outer diameter of the reaction disk 10 is set to be slightly larger than the inner diameter of the tubular portion 12a of the retainer 12 described above. Then, the base portion 11a of the output shaft 11 is fitted into the tubular portion 12a of the retainer 12 configured as described above, and the reaction disc 10 is press-fitted into the tubular portion 12a from the rear side thereof. The front end face 10b of the reaction disc 10 is brought into contact with the base 11a of the output shaft 11. The tubular portion 12a of the retainer 12, which accommodates and holds the base portion 11a of the output shaft 11 and the reaction disc 10 in this manner, is fitted to the outer peripheral portion of the annular projection 2b of the valve body 2 and the tubular portion 12a. The contact portion 12c, which is the rear end of the valve body 2, is in contact with the step end surface 2c of the valve body 2. As a result, the rear end surface 10a of the reaction disc 10 abuts on the tip surface of the annular projection 2b, and at the same time, a gap is formed between the retaining portion 12b of the retainer 12 and the base portion 11a of the output shaft 11. .. Further, in this embodiment, the rubber O-ring 14 mounted on the outer peripheral portion of the annular protrusion 2b is used to maintain the airtightness between the inner peripheral surface of the cylindrical portion 12a and the outer peripheral portion of the annular protrusion 2b. ing. According to the structure of this embodiment, the rear end surface 10a of the reaction disc 10 is brought into contact with the front end surface of the annular projection 2b, so that the front side opening of the through hole 2a of the valve body 2 is performed as in the conventional case. And the contact portion between the rear end surface 10a of the reaction disc 10 and the tip end surface of the annular projection 2b is connected to the cylindrical portion 12a of the retainer 12 and the outer peripheral portion of the reaction disc 10 which is in close contact with the tubular portion 12a. It can be sealed with the O-ring 14. Therefore, in the initial stage of operation of the brake booster in which the input shaft 9 is moved forward, the projection of the tip end surface 6a of the valve plunger 6 slightly contacts the rear end surface 10a of the reaction disc 10 to cause the reaction disc 10 to move. Airtightness between the rear end surface 10a and the tip end surface of the annular projection 2b may be incomplete. In this case, the contact portion between the rear end surface 10a of the reaction disc 10 and the tip surface of the annular protrusion 2b is sealed by the tubular portion 12a of the retainer 12, the outer peripheral portion of the reaction disc 10 and the O-ring 14. Therefore, it is possible to prevent the atmosphere existing in the through hole 2a of the valve body 2 from leaking into the constant pressure chamber A from between the rear end surface 10a of the reaction disk 10 and the tip end surface of the annular projection 2b. You can stop. Further, since the airtightness between the reaction disc and the valve body 2 can be surely maintained in this manner, the tip end surface 6a of the valve plunger 6 in the inoperative state shown in the figure is much more effective than the conventional one. The rear end face 10a can be brought into close contact with the rear end face 10a, so that the so-called jumping, which is a sudden increase in output when the brake booster is activated, can be set to a small value. Moreover, since the tip end surface 6a of the valve plunger 6 can be brought closer to the reaction disc 10 as compared with the conventional case, the loss stroke of the input shaft 9 during the operation of the brake booster can be reduced as compared with the conventional case. You can (Second Embodiment) FIG. 2 shows a second embodiment of the present invention. In this second embodiment, assuming the retainer 112 in the first embodiment described above, the tubular portion 112a and the tubular portion 112a thereof are assumed to be in contact with each other. A step portion 112d that is continuous in the circumferential direction is formed at the boundary with the contact portion 112C, and the O-ring 114 is mounted in the space formed by the step portion 112d. The other structure is the same as that of the first embodiment, and each member corresponding to the first embodiment has a member number added with 100. Even with the configuration of the second embodiment as described above, it is apparent that the same operational effects as the above-described first embodiment can be obtained.

[Effect of the device]

 As described above, according to the present invention, it is possible to prevent airtight leakage between the reaction disc and the valve body.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

2 Valve Body 2a Through Hole 6 Valve Plunger 10 Reaction Disc 11 Output Shaft 11a Base 12 Retainer 12a Cylindrical Part 12c Abutment (Rear Side End) 14 O-Ring (Seal Member)

Claims (1)

[Scope of utility model registration request] 1. A valve body slidably provided in a shell, a valve plunger constituting a part of a valve mechanism, slidably fitted in a through hole formed in the valve body, and the through hole. Is formed between the end face of the valve body whose front end is open and the base of the output shaft, and the reaction disc whose rear end face is opposed to the front end face of the valve plunger, and is formed into a bottomed tubular shape. In the booster, the base portion of the output shaft and the reaction disc are housed and held in the tubular portion, and the retainer is provided in which the rear end of the tubular portion is brought into pressure contact with the end surface of the valve body. When the reaction disc is press-fitted into the tubular portion of the retainer to maintain airtightness between the outer peripheral portion of the reaction disc and the tubular portion of the retainer that is in close contact with the outer peripheral portion of the reaction disc. Moni, booster, characterized in that a sealing member for holding airtightness between the end face of the rear end portion abutting the valve body to that of the cylindrical portion of the retainer.