JPH0633769U - Booster valve mechanism - Google Patents

Abstract

(57) [Summary] [Structure] The valve mechanism of the booster includes a valve body 10 made of a substantially cylindrical elastic member. The valve body 10 has a valve body 2 on the outer peripheral side at the front end surface thereof. First valve seat 6
An annular first seat portion 10a which is brought into contact with and separated from the second annular seat portion 10a which is brought into contact with and separated from the second valve seat 8 of the valve plunger 7 on the inner peripheral side.
The seat portion 10b is formed, and the second seat portion 10 is formed.
b is formed so as to project toward the front side. In the present invention, the annular groove 10 is provided adjacent to the second seat portion 10b.
e is formed. [Effect] When the second seat portion 10b is compressed and deformed by the spring 9, the second seat portion 10b is elastically deformed by the amount that the second seat portion 10b is bent toward the annular groove 10e on the outer peripheral side, as compared with the conventional one without the annular groove 10e. Since the amount can be increased, the hysteresis can be increased.

Description

[Detailed description of the device] [Industrial applications]

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

[Prior art]

 Conventionally, a valve mechanism of a booster generally includes a valve body made of a substantially cylindrical elastic member and an annular body 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 of the valve body. The first seat portion, the annular second seat portion provided on the inner peripheral side of the front end surface, formed to project toward the front side, and brought into contact with and separated from the second valve seat of the valve plunger; It is equipped with a backup plate that is provided on the rear side of the front side end face and supports both of the above-mentioned seat parts, and switches the fluid circuit between the variable pressure chamber formed in the shell, the constant pressure chamber, and the pressure fluid source. I have to. In the valve mechanism of the conventional negative pressure type booster, the second seat portion of the valve body and the second valve seat of the valve plunger are seated in the non-actuated state of the booster so that the atmospheric valve formed by the two is seated. The valve body is closed, and 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 formed in the shell of the booster and the variable pressure chamber communicate with each other through the vacuum valve, so that the negative pressure constantly introduced into the constant pressure chamber is changed through the vacuum valve. Will be introduced to. When the brake pedal is stepped on from this state and the valve plunger moves forward, the vacuum valve is first closed to cut off the communication between the constant pressure chamber and the variable pressure chamber, and then the atmospheric valve is opened to introduce the atmospheric pressure into the variable pressure chamber. The booster is made to perform a boosting action by the pressure difference between the constant pressure chamber and the variable pressure chamber. Next, when the brake pedal is released from the operating state and the valve plunger retracts, the atmosphere valve is first closed to shut off the communication between the variable pressure chamber and the atmosphere, and then the vacuum valve is opened to open the constant pressure chamber and the variable pressure chamber. The atmosphere in the variable pressure chamber will be discharged to the constant pressure chamber. In the servo-balanced state of the booster, both the vacuum valve and the atmosphere valve are closed, and in order to increase the output by opening the atmosphere valve from this state, the stepping force of the brake pedal is slightly increased. On the other hand, in order to open the vacuum valve and reduce the output, the depression force of the brake pedal needs to be slightly reduced. It has been known that the difference between the two pedaling forces appears as hysteresis.

[Problems to be solved by the device]

 By the way, the above-mentioned hysteresis can be increased by softening the valve body made of an elastic member, but if it is too soft, durability will be a problem. On the other hand, by increasing the axial thickness between each seat and the backup plate, the amount of elastic deformation of the valve body in each seat can be increased, so that the hysteresis can be achieved without softening the elastic member. Can be increased. However, in this case, there is a drawback in that the axial dimension of the booster is increased by the increase in the wall thickness. In view of such circumstances, the present invention provides a valve mechanism for a booster that can increase hysteresis without increasing the axial dimension of the booster.

[Means for Solving the Problems]

 That is, according to the present invention, in the valve mechanism of the above-described booster, the first valve is formed on the front side end surface of the valve body between the first seat portion and the second seat portion so as to project toward the front side. An annular groove is formed adjacent to the two sheet portions.

[Action]

 According to such a configuration, in the non-actuated state of the booster in which the second seat portion is seated on the second valve seat and the first seat portion and the first seat portion are separated from each other, the second seat portion is not operated. The elastic deformation of the seated second seat portion is maximum. On the other hand, in the operating state of the booster in which the first seat portion is seated on the first valve seat and the second valve seat is separated from the second seat portion, the second seat portion has no effect. Since no acting force is exerted, the second seat portion bulges and returns toward the front side by its own elasticity. That is, when the booster shifts from the actuated state to the non-actuated state, the second seat portion changes from the uncompressed state to the maximum compressed state. Not only is it compressed toward the rear side in the axial direction, but it is also elastically deformed toward the inside of the annular groove on the outer peripheral side of the second seat portion. In other words, the second sheet portion has the same effect as that of increasing the thickness of the second sheet portion by the amount of bending of the second sheet portion toward the annular groove side provided on the outer peripheral side thereof. Can be obtained. Therefore, the amount of elastic deformation of the second seat portion can be increased by the amount of the second seat portion bending toward the annular groove on the outer peripheral side thereof, so that the thickness of the front end portion of the valve body is increased. Without increasing the axial dimension of the booster, the hysteresis can be increased.

【Example】

 The present invention will be described below with reference to the illustrated embodiment. FIG. 1 shows a main part of a negative pressure type brake booster. A generally cylindrical valve body 2 is provided in a shell 1 in a sliding manner. 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 an annular second valve seat 8 formed at the right end of a valve plunger 7 slidably provided on the valve seat 2, and a valve body 10 seated on both valve seats 6 and 8 from the right side of FIG. 1 by a spring 9. Is equipped with. The surface of the second valve seat 8 is formed into a spherical surface having a required radius R (FIG. 2), and 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 connected to the valve plunger 7. The part is connected to 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 seated on the first valve seat 6 on the outer peripheral side thereof and the inner peripheral side of the valve seat 10a. An annular second seat portion 10b seated on the second valve seat 8 is formed. Although the surface of the above-mentioned first sheet portion 10a is flat, the above-mentioned second sheet portion 10b is formed so as to project toward the front side so as to have a substantially semicircular cross section. 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. Further, 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, from the rear side thereof, the spring 9 is provided. 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. The seat portions 10a and 10b can come into contact with and separate from the valve seats 6 and 8. Further, the end portion 10d on the rear side 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 19 via a constant pressure passage 18 formed in the valve body 2 in the axial direction. The space on the outer peripheral side of 13 is communicated with the variable pressure chamber 21 via a radial variable pressure passage 20 formed in the valve body 2. Further, the space on the inner peripheral side of the atmospheric valve 13 is communicated with the atmosphere via a pressure passage 22 formed by the inner peripheral surface of the valve body 2 and a filter 23 provided therein. The above configuration and the operation based on it are the same as those of the conventionally known brake booster. Therefore, as shown in an enlarged manner in FIG. 2, in the present embodiment, the second seat portion 10b is provided on the front end surface of the valve body 10 between the first seat portion 10a and the second seat portion 10b. And an annular groove 10e is formed adjacent to. Since the valve body 10 of the present embodiment is formed as described above, it is possible to increase the so-called hysteresis, which is the difference between the inputs when the brake pedal is depressed and when the brake pedal is released. That is, in the above configuration, in the non-actuated state shown in FIG. 2 in which the vacuum valve 12 is open and the atmospheric valve 13 is closed, the second seat portion 10b has the elastic force of the spring 9 provided on the rear side thereof. Since it is pressed against the second valve seat 8, the elastic deformation of the second seat portion 10b is maximized. On the other hand, in the operating state of FIG. 3 in which the vacuum valve 12 is closed and the atmospheric valve 13 is open, no action force acts on the second seat portion 10b, so that the second seat portion 10b is self-contained. The elasticity of bulges back toward the front side, maintaining a natural state. From the operating state of the booster shown in FIG. 3, that is, when the brake pedal is stepped on from the state where the brake pedal is stepped on, the valve body 2 moves forward relative to the valve plunger 2. The atmosphere valve 13 is closed and the servo balance is established. In this state, the second seat portion 10b constituting the atmosphere valve 13 is only lightly in contact with the second valve seat 8, so that there is almost no elastic deformation of the second seat portion 10b. Therefore, when the depression force of the brake pedal is increased, the atmospheric valve 13 opens immediately. On the other hand, when the depression force of the brake pedal is reduced from the state where the second seat portion 10b configuring the atmosphere valve 13 is lightly in contact with the second valve seat 8, the second seat portion 10b is The rear side is compressed only by the decrease in the stepping force, that is, the increase in the contact pressure. At this time, the second seat portion 10b is compressed toward the rear side in the axial direction and also elastically deformed toward the inside of the annular groove 10e on the outer peripheral side of the second seat portion 10b. That is, the second seat portion 10b can be elastically deformed toward the annular groove 10e side more easily than in the case where the second seat portion 10b has no annular groove 10e. A large amount of elastic deformation can be secured in the same manner as when the thickness of the second sheet portion 10b is increased by the amount of bending toward the annular groove 10e side provided on the outer peripheral side thereof. When the depression force of the brake pedal is further reduced, the second seat portion 10b is separated from the second valve seat 8 when the elastic deformation of the second seat portion 10b is maximized, and the vacuum valve 12 is released. The atmosphere that has opened and is introduced into the variable pressure chamber 21 is discharged to the constant pressure chamber 19, so that the brake booster is returned to the non-operating position. As can be understood from the above description, the stepping force at the moment when the atmospheric valve 13 is closed while the vacuum valve 12 is closed and the stepping force at the moment when the vacuum valve 12 is opened from the state where the atmospheric valve 13 is closed are defined. Causes a difference depending on the amount of elastic deformation of the second seat portion 10b, which causes a difference between the output increase and the output decrease of the booster, that is, hysteresis. In this embodiment, the amount of elastic deformation of the second seat portion 10b can be made larger than that of the conventional one without the annular groove 10e by the amount of bending toward the annular groove 10e on the outer peripheral side thereof. The hysteresis can be increased without increasing the axial dimension of the device and without softening the valve body 10 made of an elastic member. As shown in FIG. 2, since the second valve seat 8 of the valve plunger 7 has a spherical shape in the above embodiment, the second seat portion can be changed by changing the radius R of the second valve seat 8. The amount of elastic deformation of 10b can be changed, thereby changing the amount of hysteresis. That is, the size of the hysteresis can be adjusted by the combination of the second valve seat 8 and the annular groove 10e in which the size of the radius R is different.

[Effect of device]

 As described above, according to the present invention, it is possible to obtain an effect that the hysteresis can be increased without increasing the axial dimension of the booster and without reducing the durability of the valve body.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a diagram showing an operating state different from that in FIG. 2;

[Explanation of symbols]

2 ... Valve body 5 ... Valve mechanism 6 ... First valve seat 7 ... Valve plunger 8 ... Second valve seat 9 ... Spring 10 ... Valve body 10a ... First seat part 10b
... 2nd seat part 10e ... Annular groove 14 ... Backup plate

Claims (1)

[Scope of utility model registration request] 1. A valve body made of a substantially tubular elastic member, an annular first seat portion formed on an outer peripheral side of a front end surface of the valve body and contacting and separating from a first valve seat of a valve body, An annular second seat portion that is provided on the inner peripheral side of the front end surface, is formed to project toward the front side, and is brought into contact with and separated from the second valve seat of the valve plunger; and the rear end of the front end surface of the valve body. A valve mechanism of a booster, comprising: a backup plate that is provided to support both seat portions, and that switches a fluid circuit between a variable pressure chamber formed in a shell and a constant pressure chamber and a pressure fluid source. A booster, characterized in that an annular groove is formed on the front end face of the valve body between the second seat part and the second seat part so as to be adjacent to the second seat part projecting toward the front side. Valve mechanism.