JPH0558544U - Booster valve mechanism - Google Patents

Abstract

(57) [Summary] [Structure] The valve body 10 constituting the valve mechanism 5 of the booster is
The valve body 2 includes a first seat portion 10a that contacts and separates from the first valve seat 6 and a second seat portion 10b that contacts and separates from the second valve seat 8 of the valve plunger 7. The outer peripheral side 14b of the backup plate 14 that supports the seat portions is curved to the rear side rather than the inner peripheral side 14a thereof, thereby increasing the axial thickness of the first seat portion 10a. Since the amount of elastic deformation of the first seat portion 10a can be increased, the hysteresis can be increased without softening the valve body 10 and lowering the durability. Further, since the inner peripheral side 14a of the backup plate on which the spring 9 for urging the valve body 10 toward the valve seats 6 and 8 is arranged can have the same size as that of the conventional one, the axial direction of the booster can be made. The size does not increase.

Description

[Detailed description of the device] [Industrial application]

 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 contacting and separating from the first valve seat of the valve body. A first seat portion, an annular second seat portion formed on the inner peripheral side of the front end surface and contacting with and separating from a second valve seat of the valve plunger; the first seat portion and the second seat portion; A backup plate which is provided on the rear side of the backup plate to support both seat portions, and a spring which is arranged on the inner peripheral side of the backup plate and biases the seat portions toward the valve seats. ing. In this type of valve mechanism, in the non-actuated state of the booster, the second seat portion of the valve body and the second valve seat of the valve plunger are seated to close the atmosphere valve formed by both, and the valve body is also closed. And the first valve seat of the valve body is 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 via the vacuum valve, so that the negative pressure that is always introduced into the constant pressure chamber enters the variable pressure chamber via the vacuum valve. be introduced. When the brake pedal is depressed 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 depressed 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 atmospheric valve are closed, and in order to increase the output by opening the atmospheric 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]

 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, if the axial thickness between each seat and the backup plate is increased, the amount of elastic deformation of the valve body in each seat can be increased, so that hysteresis can be obtained without softening the elastic member. Can be made bigger. However, in this case, when the surface of each seat is used as a reference, the result is that the back-up plate is moved to the rear side, so the spring is compressed by that amount, and in order to avoid this, the backup plate should be replaced by the rear plate. The axial dimension of the booster had to be increased by the amount moved to the side. In view of such circumstances, the present invention provides a valve mechanism for a booster that can increase hysteresis without impairing the durability of the valve element and without increasing the axial dimension of the booster. To do.

[Means for Solving the Problems]

 That is, according to the present invention, in the above-described conventional valve mechanism, the outer peripheral side of the backup plate is curved to the rear side rather than the inner peripheral side where the spring is disposed.

[Action]

 With such a configuration, the outer peripheral side is curved to the rear side rather than the inner peripheral side of the backup plate on which the spring is arranged, so that the inner peripheral side of the backup plate on which the spring is arranged is curved. Does not need to be resized and therefore does not require a larger booster axial dimension. On the other hand, the axial thickness of the valve body in the first seat portion can be increased by bending the outer peripheral side of the backup plate to the rear side, so that the valve body does not need to be softened. The hysteresis can be increased without lowering the durability.

【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 an annular second valve seat 8 formed at the right end of a valve plunger 7 slidably provided on the second valve seat, 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 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. The valve body 10 is reinforced by embedding a ring-shaped backup plate 14 on the rear side of both seats 10a and 10b, and one end of the spring 9 is elastically attached to the inner peripheral side of the backup plate 14. The seat portions 10a and 10b are urged toward the valve seats 6 and 8 in contact with each other. 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 reduced wall thickness, and the curved portion 10c expands and contracts in the axial direction to form 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 thickened and 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 21 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 23 via a radial variable pressure passage 22 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 24 formed by the inner peripheral surface of the valve body 2 and a filter 25 provided therein. The above configuration and the operation based on it are the same as those of the conventionally known brake booster. However, in the prior art, the backup plate 14 was formed in a flat plate shape as shown by the imaginary line in FIG. It is curved to the rear side, whereby the axial thickness of the first seat portion 10a is increased by the curved amount L as compared with the conventional case. In the above configuration, when the input shaft 11 and the valve plunger are advanced from the non-operating state in which the vacuum valve 12 is opened and the atmospheric valve 13 is closed, the vacuum valve 12 is first closed and then the atmospheric valve 13 is opened. The atmosphere is introduced into the transformation chamber 23. As a result, the valve body 2 is advanced and the braking action is performed. If the depression force of the brake pedal is kept constant in this state, the valve body 2 advances relative to the valve plunger 7, and the atmospheric valve 13 closes. In this state, since the second seat portion 10b forming the atmospheric valve 13 is only lightly in contact with the second valve seat 8, 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 will be opened immediately. On the other hand, when the depression force of the brake pedal is reduced from the state in which the second seat portion 10b constituting the atmosphere valve 13 is lightly in contact with the second valve seat 8 described above, the valve plunger 7 of the valve plunger 7 is first moved. Due to the retreat, the contact pressure between the second seat portion 10b and the second valve seat 8 increases, which increases the elastic deformation amount of the second seat portion 10b. On the other hand, when the atmosphere valve 13 is open, the first valve seat 6 and the first seat portion 10a that form the vacuum valve 12 are pressed against each other by the elastic force of the spring 9, and depending on the elastic force. As a result, the first sheet portion 10a is relatively elastically deformed. Then, when the valve plunger 7 is retracted, the contact pressure between the second seat portion 10b and the second valve seat 8 increases as described above, but at the same time, the first valve seat 6 and the first seat portion 10a. Since the contact pressure with is reduced, the elastic deformation amount of the first sheet portion 10a is reduced. When the contact pressure between the first valve seat 6 and the first seat portion 10a becomes almost zero, the first valve seat 6 and the first seat portion 10a are separated from each other and the vacuum valve 12 opens. 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 in accordance with the elastic deformation of the seat portions 10a, 10b, which causes a difference between the output of the booster and the output of the booster, that is, hysteresis. The hysteresis increases as the amount of elastic deformation of each of the seat portions 10a and 10b increases, but in this embodiment, the axial thickness of the first seat portion 10a is increased by the amount of the curvature L as compared with the conventional case. Therefore, the amount of elastic deformation of the first sheet portion 10a can be increased by that amount, and accordingly, the hysteresis can be increased without softening the elastic member and lowering the durability. On the other hand, since the inner peripheral side 14a of the backup plate 14 on which the spring 9 is arranged remains the same as before, it is not necessary to change the size of that portion, and therefore it is not necessary to increase the axial size of the booster.

[Effect of the device]

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

[Submission date] April 9, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Detailed explanation of the device

[Correction method] Change

[Correction content] [Detailed description of the device] [Industrial application]

 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 contacting and separating from the first valve seat of the valve body. A first seat portion, an annular second seat portion formed on the inner peripheral side of the front end surface and contacting with and separating from a second valve seat of the valve plunger; the first seat portion and the second seat portion; A backup plate which is provided on the rear side of the backup plate to support both seat portions, and a spring which is arranged on the inner peripheral side of the backup plate and biases the seat portions toward the valve seats. ing. In this type of valve mechanism, in the non-actuated state of the booster, the second seat portion of the valve body and the second valve seat of the valve plunger are seated to close the atmosphere valve formed by both, and the valve body is also closed. And the first valve seat of the valve body is 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 via the vacuum valve, so that the negative pressure that is always introduced into the constant pressure chamber enters the variable pressure chamber via the vacuum valve. be introduced. When the brake pedal is depressed 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 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, it is necessary to slightly reduce the depression force of the brake pedal. It has been known that the difference between the two pedaling forces appears as hysteresis.

The above 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, if the axial thickness between each seat and the backup plate is increased, the amount of elastic deformation of the valve body in each seat can be increased, so that hysteresis can be obtained without softening the elastic member. Can be made bigger. However, in this case, when the surface of each seat is used as a reference, the result is that the back-up plate is moved to the rear side, so the spring is compressed by that amount, and in order to avoid this, the backup plate should be replaced by the rear plate. The axial dimension of the booster had to be increased by the amount moved to the side. In view of such circumstances, the present invention provides a valve mechanism for a booster that can increase hysteresis without impairing the durability of the valve element and without increasing the axial dimension of the booster. To do.

[Means for Solving the Problems]

 That is, according to the present invention, in the above-described conventional valve mechanism, the outer peripheral side of the backup plate is curved to the rear side rather than the inner peripheral side where the spring is disposed.

[Action]

 With such a configuration, the outer peripheral side is curved to the rear side rather than the inner peripheral side of the backup plate on which the spring is arranged, so that the inner peripheral side of the backup plate on which the spring is arranged is curved. Does not need to be resized and therefore does not require a larger booster axial dimension. On the other hand, the axial thickness of the valve body in the first seat portion can be increased by bending the outer peripheral side of the backup plate to the rear side, so that the valve body does not need to be softened. The hysteresis can be increased without lowering the durability.

【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 an annular second valve seat 8 formed at the right end of a valve plunger 7 slidably provided on the second valve seat, 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 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. The valve body 10 is reinforced by embedding a ring-shaped backup plate 14 on the rear side of both seats 10a and 10b, and one end of the spring 9 is elastically attached to the inner peripheral side of the backup plate 14. The seat portions 10a and 10b are urged toward the valve seats 6 and 8 in contact with each other. 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 reduced wall thickness, and the curved portion 10c expands and contracts in the axial direction to form 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 thickened and 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 21 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 23 via a radial variable pressure passage 22 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 24 formed by the inner peripheral surface of the valve body 2 and a filter 25 provided therein. The above configuration and the operation based on it are the same as those of the conventionally known brake booster. However, in the prior art, the backup plate 14 was formed in a flat plate shape as shown by the imaginary line in FIG. It is curved to the rear side, and as a result, the wall thickness in the axial direction of the first seat portion 10a is increased by the curved amount L as compared with the conventional case. In the above configuration, when the input shaft 11 and the valve plunger are advanced from the non-operating state in which the vacuum valve 12 is opened and the atmospheric valve 13 is closed, the vacuum valve 12 is first closed and then the atmospheric valve 13 is opened. The atmosphere is introduced into the transformation chamber 23. As a result, the valve body 2 is advanced and the braking action is performed. If the depression force of the brake pedal is kept constant in this state, the valve body 2 advances relative to the valve plunger 7, and the atmospheric valve 13 closes. In this state, since the second seat portion 10b forming the atmospheric valve 13 is only lightly in contact with the second valve seat 8, 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 will be opened immediately. On the other hand, when the depression force of the brake pedal is reduced from the state in which the second seat portion 10b constituting the atmosphere valve 13 is lightly in contact with the second valve seat 8 described above, the valve plunger 7 of the valve plunger 7 is first moved. Due to the retreat, the contact pressure between the second seat portion 10b and the second valve seat 8 increases, which increases the elastic deformation amount of the second seat portion 10b. On the other hand, when the atmospheric valve 13 is open, the first valve seat 6 and the first seat portion 10a, which form the vacuum valve 12, are pressed against each other by the elastic force of the spring 9, and depending on the elastic force. As a result, the first sheet portion 10a is relatively elastically deformed. Then, when the valve plunger 7 is retracted, the contact pressure between the second seat portion 10b and the second valve seat 8 increases as described above, but at the same time, the first valve seat 6 and the first seat portion 10a. Since the contact pressure with is reduced, the elastic deformation amount of the first sheet portion 10a is reduced. When the contact pressure between the first valve seat 6 and the first seat portion 10a becomes almost zero, the first valve seat 6 and the first seat portion 10a are separated from each other and the vacuum valve 12 opens. 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 in accordance with the elastic deformation of the seat portions 10a, 10b, which causes a difference between the output of the booster and the output of the booster, that is, hysteresis. The hysteresis increases as the amount of elastic deformation of each of the seat portions 10a and 10b increases, but in this embodiment, the axial thickness of the first seat portion 10a is increased by the amount of the curvature L as compared with the conventional case. Therefore, the elastic deformation amount of the first sheet portion 10a can be increased by that amount, and accordingly, the hysteresis can be increased without softening the elastic member and lowering the durability. On the other hand, since the inner peripheral side 14a of the backup plate 14 on which the spring 9 is arranged remains the same, it is not necessary to change the size of that portion, and therefore it is not necessary to increase the axial size of the booster.

[Effect of the device]

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

[Brief description of drawings]

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

[Explanation of symbols]

 2 ... Valve body 5 ... Valve mechanism 6 ... 1st valve seat 7 ... Valve plunger 8 ... 2nd valve seat 9 ... Spring 10 ... Valve body 10a ... 1st seat part 10b ... 2nd seat part 14 ... Backup plate 14a ... Inner periphery Side 14b ... Outer peripheral side

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 which is formed on the inner peripheral side of the front end surface and is brought into contact with and separated from the second valve seat of the valve plunger;
A backup plate that is provided on the rear side of the seat portion and the second seat portion and supports both seat portions, and is further disposed on the inner peripheral side of the backup plate, and attaches each seat portion to each valve seat. In a valve mechanism of a booster including a biasing spring, the booster is characterized in that an outer peripheral side of the backup plate is curved to a rear side rather than an inner peripheral side where the spring is arranged. The valve mechanism of the device.