JPH0562377U - Booster - Google Patents

Abstract

(57) [Summary] [Structure] In the operating state of the brake booster, the open atmospheric valve 13 and the opening 19a of the variable pressure passage 19 are configured to overlap in the axial direction. [Effect] Since the atmosphere valve 13 and the variable pressure passage 19 communicate with each other at the shortest distance, as compared with the conventional one shown in FIG.
The circulation path of the atmosphere from the atmosphere valve 13 to the variable pressure chamber 20 is shortened. Therefore, when the brake booster operates, the atmosphere is quickly introduced from the atmosphere valve 13 toward the variable pressure chamber 20, and therefore, the responsiveness when the brake booster operates becomes good.

Description

[Detailed description of the device] [Industrial applications]

 The present invention relates to a booster, and more particularly to improvement of a valve mechanism of the booster.

[Prior Art]

 Generally, a booster has a valve body slidably provided in a shell, a constant pressure chamber and a variable pressure chamber formed before and after a power piston provided in the valve body, and a variable pressure chamber formed in the valve body. And a variable pressure passage for communicating the variable pressure chamber with the constant pressure chamber via the valve mechanism and the constant pressure passage, and the valve mechanism with an annular first valve seat formed in the valve body. An annular first seat portion which is formed on the outer peripheral side of the front end surface of the valve body and is brought into contact with and separated from the first valve seat; and an annular second seat portion which is formed on a valve plunger provided on the valve body in a sliding manner. The valve seat and the annular second seat portion formed on the inner peripheral side of the front end surface of the valve body and contacting and separating from the second valve seat are configured. In the conventional valve mechanism described above, when the booster is not operating, the second seat portion of the valve body and the second valve seat of the valve plunger are seated to close the atmospheric valve formed by the two. Further, the first seat portion of the valve body and the first valve seat of the valve body are separated from each other to open the vacuum valve formed by the two. In this state, the constant pressure chamber and the pressure changing chamber provided in the shell communicate with each other through the vacuum valve, and thus the negative pressure always introduced into the constant pressure chamber is introduced into the variable pressure chamber through the vacuum valve. When the brake pedal is stepped on from this state and the valve plunger moves forward, the vacuum valve is first closed to shut off the communication between the constant pressure chamber and the variable pressure chamber, and then the atmospheric valve is opened to transform the atmosphere through the variable pressure passage. Introduced into the chamber, the booster is made to boost by the pressure difference between the constant pressure chamber and the variable pressure chamber.

[Problems to be solved by the device]

 By the way, in the conventional booster described above, the end opening of the variable pressure passage on the valve mechanism side is located on the front side with respect to the position of the atmospheric valve when the booster operates, and therefore, the variable pressure passage is The circulation path of the atmosphere was lengthened by the distance that the end opening of the and the atmospheric valve were separated in the axial direction. Further, in the conventional booster, the air flowing from the atmospheric valve during operation flows into the variable pressure chamber through the atmospheric valve opening, the gap between the outer peripheral portion of the valve plunger and the inner peripheral portion of the valve body, and the variable pressure passage. However, at this time, the atmosphere is bent at three places: the opening of the atmospheric valve, the outer peripheral end of the valve plunger, and the opening of the variable pressure passage. Furthermore, the area of the gap between the outer peripheral portion of the valve plunger and the inner peripheral portion of the valve body cannot always be made sufficiently large. As described above, in the conventional art, the air flow path is long by the axial distance between the end opening of the variable pressure passage and the atmosphere valve, and the ventilation resistance due to the bending of the inflow path between them is large. Further, the outer peripheral portion of the valve plunger has a throttling effect due to the gap in the inner peripheral portion of the valve body, which slows down the introduction speed of the atmosphere, and therefore has a drawback that the response of the booster device during operation is poor.

[Means for Solving the Problems]

 In view of such circumstances, the present invention has a valve body slidably provided in a shell, a constant pressure chamber and a variable pressure chamber formed before and after a power piston provided in the valve body, and a valve body. A variable pressure passage for communicating the variable pressure chamber with the valve mechanism, and a variable pressure passage for communicating the variable pressure chamber with the constant pressure chamber via the valve mechanism and the constant pressure passage. A valve seat, an annular first seat portion formed on the outer peripheral side of the front end face of the valve body and brought into contact with and separated from the first valve seat, and an annular plunger formed on a valve plunger slidably provided on the valve body. A booster including a second valve seat and an annular second seat portion formed on an inner peripheral side of a front end surface of the valve body and brought into contact with and separated from the second valve seat. With the seat portion seated on the first valve seat, The second sheet over the isolation portions of the body is obtained to face the opening of the variable pressure passage.

[Action]

 According to such a configuration, the booster is in the operating state, that is, the first seat portion is seated on the first valve seat, the vacuum valve constituted by them is closed, and the second valve seat and the second seat are closed. When the atmospheric valve formed by the parts is separated from each other and is opened, the gap (atmospheric valve in the open state) generated between the second valve seat and the second seat is defined by the opening of the variable pressure passage and the shaft. To overlap in the direction. In this way, when the booster is operated, the atmosphere valve and the opening of the variable pressure passage can be communicated with each other at the shortest distance, so that the circulation path of the atmosphere from the atmospheric valve to the variable pressure chamber can be improved. In addition to being shorter than before, the bent portion of the atmosphere can be reduced from three in the past to one, and since it does not pass through the outer periphery of the valve plunger, it is not throttled. Therefore, it becomes possible to increase the introduction speed of the atmosphere from the atmosphere valve into the variable pressure chamber, and the response at the time of operation of the booster becomes better than in the conventional case.

【Example】

 The present invention will be described below with reference to the illustrated embodiment. FIG. 1 shows a main part of a brake booster, in which a generally cylindrical valve body 2 is slidably provided in a shell 1. The rear side of the valve body 2 is projected to the outside through the opening of the shell 1. A valve mechanism 5 is housed in the valve body 2. The valve mechanism 5 includes an annular first valve seat 6 formed in the valve body 2 and a valve body inside the annular first valve seat 6. 2 has a ring-shaped second valve seat 8 formed at the right end of a valve plunger 7 slidably provided in the through hole 2a, and further seated on both valve seats 6 and 8 from the right side in FIG. 1 by a spring 9. And a valve body 10 for The left end of the input shaft 11 is connected to the valve plunger 7, and the right end of the input shaft 11 is interlocked with a brake pedal (not shown). The valve body 10 is made of rubber and has a substantially cylindrical shape. The front end surface of the valve body 10 has an annular first seat portion 10a which is seated on the first valve seat 6 on the outer peripheral side thereof and the inner peripheral surface of the first seat portion 10a. An annular second seat portion 10b seated on the second valve seat 8 is formed. The first valve seat 6 and the first seat portion 10a constitute a vacuum valve 12, and the second valve seat 8 and the second seat portion 10b constitute an atmosphere valve 13, respectively. In addition, the valve body 10 is reinforced by providing a ring-shaped backup plate 14 on the rear side of both seat portions 10a, 10b, and on the inner peripheral side of this backup plate 14, the spring 9 from the rear side thereof. The seat portions 10a, 10b are biased toward the valve seats 6, 8 by elastically contacting one end thereof. The axial portion of the valve body 10 on the rear side of the seat portions 10a and 10b is a curved portion 10c having a thin wall thickness, and the curved portion 10c expands and contracts in the axial direction to allow the above-mentioned both portions to be bent. The seat portions 10a and 10b can come into contact with and separate from the valve seats 6 and 8. Further, the rear end portion 10d of the valve body 10 is made thick and is fixed to the inner peripheral surface of the valve body 2 by a retainer 15. The space on the outer peripheral side of the vacuum valve 12 is communicated with a constant pressure chamber (not shown) via an axial constant pressure passage 18 formed in the valve body 2, and on the inner peripheral side of the vacuum valve 12 as well. The space on the outer peripheral side of the atmosphere valve 13 is communicated with the variable pressure chamber 20 via a radial variable pressure passage 19 formed in the valve body 2. Further, the space on the inner peripheral side of the atmosphere valve 13 is communicated with the atmosphere via a pressure passage 21 formed by the inner peripheral surface of the valve body 2 and a filter 22 provided therein. The above configuration and the operation based on it are the same as those of the conventionally known brake booster. However, in this embodiment, the inner peripheral side portion of the backup plate 14 is bulged toward the front side from the outer peripheral side portion thereof, and is supported by the inner peripheral side portion of the back-up plate 14. The inner peripheral side of the front end face of 10 is made to bulge toward the front side rather than the outer peripheral side. As a result, the second seat portion 10b is always located on the front side of the first seat portion 10a. In this embodiment, as described above, the inner peripheral side of the front end face of the valve body 10 is bulged toward the front side, but the thickness of the front end face is substantially the same on both the inner peripheral side and the outer peripheral side. The same. Further, in this embodiment, the variable pressure passage 19 provided in the valve body 2 in the radial direction is located on the front side adjacent to the first valve seat 6 as far as it comes out. As a result, in the present embodiment, in the operating state of the brake booster, the opened atmospheric valve 13 is located closer to the front side than the rear end of the opening 19a of the variable pressure passage 19, and therefore the brake In the operating state of the booster, the atmosphere valve 13 and the opening 19a of the variable pressure passage 19 overlap in the axial direction. According to the configuration of the present embodiment, the open air valve 13 (the gap between the second valve seat 8 and the second seat portion 10b) in the operating state of the brake booster shown in FIG. The variable pressure passage 19 communicates with the shortest distance. This makes it possible to shorten the air circulation path from the atmosphere valve 13 to the variable pressure chamber 20 as compared with the conventional one, and the bent portion of the atmosphere is only one at the atmosphere valve opening. In addition, since there is no restriction in the outer peripheral portion of the valve plunger, the introduction speed of the atmosphere into the variable pressure chamber 20 can be increased. Therefore, the responsiveness when the brake booster operates is good. Moreover, as described above, the atmosphere circulates in the shortest distance from the atmosphere valve 13 to the variable pressure passage 19 located outward in the radial direction, so that in the atmosphere circulation path from the atmospheric valve 13 to the variable pressure chamber 20. It is also possible to prevent the generation of air intake noise. In the prior art shown in FIG. 2, in contrast to the above-described embodiment, the position of the opening 19a 'of the variable pressure passage 19' is different from the position of the atmospheric valve 13 'in the open state in which the booster is operated. It was shifted to the front side. Therefore, conventionally, the atmosphere circulation path is lengthened by the distance axially separating the atmosphere valve 13 ′ and the opening 19a ′ of the variable pressure passage 19 ′, and the circulation path is a bent circulation path. Was there. Therefore, conventionally, the introduction speed of the atmosphere from the atmosphere valve 13 'into the variable pressure chamber 20' becomes slow, and the responsiveness at the time of operation is deteriorated. Moreover, since the atmospheric fluid path from the atmospheric valve 13 'to the pressure-changing passage 19' was bent, there was a drawback that an atmospheric suction noise was generated. In the present embodiment shown in FIG. 1, the second seat portion 10b of the atmospheric valve 13 in the open state is located completely on the front side of the rear end of the opening 19a of the variable pressure passage 19. However, they may be substantially at the same position in the axial direction.

[Effect of the device]

 As described above, according to the present invention, it is possible to obtain an effect that the responsiveness of the booster during operation is improved as compared with the conventional case.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a conventional technique.

[Explanation of symbols]

2 ... Valve body 5 ... Valve mechanism
6 ... 1st valve seat 7 ... Valve plunger 8 ... 2nd valve seat 1
0 ... Valve body 10a ... 1st seat part 10
b ... 2nd seat part 19 ... transformation passage 19a ... opening 2
0 ... Transformer room

Claims (1)

[Scope of utility model registration request] 1. A valve body slidably provided in a shell, a constant pressure chamber and a variable pressure chamber formed before and after a power piston provided in the valve body, and a valve mechanism formed in the valve body to form the variable pressure chamber. And a variable pressure passage communicating between the variable pressure chamber and the constant pressure chamber via the valve mechanism and the constant pressure passage, and the valve mechanism includes an annular first portion formed in the valve body.
A valve seat, an annular first seat portion formed on the outer peripheral side of the front end surface of the valve body and brought into contact with and separated from the first valve seat, and an annular first seat portion slidably provided on the valve body. A booster including a second valve seat and an annular second seat portion formed on an inner peripheral side of a front end surface of the valve body and brought into contact with and separated from the second valve seat. A booster characterized in that a second seat portion of the valve body is made to face an opening portion of the variable pressure passage while the seat portion is seated on the first valve seat.