JP3159812B2 - Pneumatic booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic booster for assisting a brake operating force in a vehicle or the like and outputting the assisted force to a master cylinder.

[0002]

2. Description of the Related Art A conventional pneumatic booster divides the inside of a shell into a negative pressure chamber and an operating pressure chamber communicating with a negative pressure source, and is slidably supported at one end side of the shell in a valve body. A power piston provided in the valve body, and a poppet valve for introducing air into the working pressure chamber by relative movement of an operating rod connected to a brake pedal in an output direction with respect to the valve body. By introducing the atmosphere into the chamber, a differential pressure is generated in the power piston, and the input from the operating rod is assisted and output.

[0003]

However, in the above-mentioned pneumatic booster, there is a limit to the magnitude of the assisting force determined by the differential pressure between the atmosphere and the negative pressure generated on both sides of the power piston. When it is necessary to guarantee the braking performance, the size of the power piston that receives the differential pressure, that is, the size of the entire pneumatic booster, or the two pairs of the negative pressure chamber and the working pressure chamber are provided. Tandem boosters and the like have to be adopted, and there is a problem that any of them requires an increase in size. Further, since the amount of the atmosphere introduced into the working pressure chamber is almost constant, the assisting force rises almost constant even when it is desired to rapidly reduce the speed.

Accordingly, an object of the present invention is to provide a pneumatic booster capable of increasing the assisting force without increasing the size and increasing the amount of increase of the assisting force when the vehicle is suddenly decelerated. To provide.

[0005]

According to a first aspect of the present invention, there is provided a pneumatic booster according to the first aspect of the present invention, wherein a negative pressure chamber and an operating pressure chamber communicating with a negative pressure source in a shell. A power piston that defines and slidably supports a valve body at one end side of the shell; and an output direction of an operating rod provided in the valve body and connected to a brake pedal with respect to the valve body. A poppet valve for introducing air into the working pressure chamber by relative movement, and by introducing air into the working pressure chamber, a differential pressure is generated in the power piston to assist the output of the operating rod and output. A compressed air source for generating compressed air, and the compressed air source and the working pressure chamber are connected to the poppet.
A flow path connected without a valve, and provided in the flow path, when the relative movement amount of the operating rod in the output direction with respect to the valve body does not reach a predetermined value, the valve is closed, and And an opening / closing valve that opens when the relative movement amount of the shutter reaches a predetermined value.

According to a second aspect of the present invention, there is provided a pneumatic booster in addition to the first aspect, wherein the on-off valve is provided.
Is the operating lock of the poppet valve.
It is characterized by being provided in series on the output direction side of the gate .

In the pneumatic booster according to a third aspect of the present invention, the inside of the shell is divided into a constant pressure chamber and a working pressure chamber, and a valve body portion is slidably supported at one end of the shell. A power piston, and a valve provided in the valve body portion, for introducing a working gas into the working pressure chamber by a relative movement of an operating rod connected to a brake pedal in an output direction with respect to the valve body portion, In a pneumatic booster that introduces a working gas into the working pressure chamber to generate a differential pressure in the power piston and assists and outputs the output of the operating rod, a compressed air as the working gas is generated. The valve body is slidably supported outside the compressed air source and a portion of the valve body protruding from the shell. A cover connected to the compressed air source and defining a compressed air chamber filled with compressed air together with the shell; a compressed air chamber provided in a valve body portion through a valve provided by a flow path; And is connected to the working pressure chamber. in addition,
In the pneumatic booster according to claim 4 of the present invention, the inside of the shell
It is divided into a negative pressure chamber communicating with the negative pressure source and a working pressure chamber.
The valve body slides at one end of the shell
A freely supported power piston and the valve body
An operator installed in the unit and connected to the brake pedal
Output direction of the toting rod with respect to the valve body
Popper for introducing air into the working pressure chamber by relative movement of
And a cut-off valve for introducing air into the working pressure chamber.
By generating a differential pressure in the power piston by the
Barometric pressure that assists the output of the operating rod and outputs
Compressed air source that generates compressed air in a power booster
And a flow path connecting the compressed air source and the working pressure chamber
And a front side with respect to the valve body provided in the flow path.
The relative movement of the operating rod in the output direction
When a predetermined value is reached, the
Block the introduction of air to the working pressure chamber and connect the flow path
An on-off valve.

[0008]

According to the pneumatic booster of the first aspect of the present invention, the brake pedal is depressed to obtain a normal deceleration, and the operating rod connected to the brake pedal is directed in the output direction with respect to the valve body. When the relative movement is made, the poppet valve introduces air into the working pressure chamber and generates a differential pressure in the power piston, which assists the input of the operating rod and outputs it. When the brake pedal is depressed with a large force, the relative movement amount of the operating rod in the output direction with respect to the valve body reaches a predetermined value (for example, the relative movement position moves until the relative movement position is near the limit position). The on-off valve is opened, and compressed air from a compressed air source that generates compressed air is introduced into the working pressure chamber through the flow path. It becomes door. As a result, a differential pressure is generated in the power piston at a speed faster than the introduction of the normal atmosphere. When the operating pressure chamber reaches the atmospheric pressure, the brake pedal is depressed to obtain a larger deceleration, and the amount of relative movement of the operating rod in the output direction with respect to the valve body reaches a predetermined value (for example, relative movement). Position is near the limit position).
The on-off valve is opened, and compressed air from a compressed air source that generates compressed air is introduced into the working pressure chamber via the flow path. As a result, the pressure in the working pressure chamber exceeds the atmospheric pressure, and a larger differential pressure acts on the power piston.

Further, according to the pneumatic booster of the second aspect of the present invention, in addition to the operation of the first aspect, the on- off valve is an operating valve of the poppet valve.
The valve is installed in series on the output side of the
There is no need to enlarge the body in the radial direction.

Further, according to the pneumatic booster according to the third aspect of the present invention, the valve body is supported by the shell, and the cover provided outside the portion of the valve body protruding from the shell. Therefore, the support of the valve body is stabilized. Further, the compressed air chamber defined by the cover and the shell is filled with compressed air, and the compressed air chamber is connected to the working pressure chamber via the valve by a flow path provided in the valve body, There is no need to configure the compressed air chamber as a separate tank from the pneumatic booster, which eliminates the need for piping work and shortens the compressed air introduction path to the working pressure chamber. Also improve. In addition, the present invention
According to the pneumatic booster of the fourth aspect, the normal deceleration
Brake pedal is depressed to obtain
The operating rod connected to the pedal is
The poppet valve moves when it moves relative to the
Introduces air into the working pressure chamber and creates a differential pressure on the power piston.
Generates and assists operating rod input and outputs
But when braking or not
To get a sharp deceleration,
Predetermined relative movement in the output direction with respect to the valve body
Value (for example, the relative movement position is near the limit position)
Brake pedal is depressed with great force
The open / close valve opens and the compressed air that generates compressed air
The compressed air from the air source is introduced into the working pressure chamber through the flow path.
Will be. This gives the power piston the usual
The differential pressure will be generated at a faster rate than the introduction of the atmosphere.
Also, when the working pressure chamber reaches atmospheric pressure,
The brake pedal is depressed to gain speed and the operator
Toning rod in output direction to valve body
Reaches a predetermined value (for example, when the relative movement position is
(Close to the limit position), the open / close valve opens
Compressed air from a compressed air source that generates compressed air,
It will be introduced into the working pressure chamber via the flow path. to this
Therefore, the pressure of the working pressure chamber exceeds the atmospheric pressure,
A larger differential pressure will act on the power piston.
You.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic booster according to a first embodiment of the present invention will be described below with reference to FIG. In the following description, the output direction indicates the output direction of the pneumatic booster (left direction in the drawing), and the counter output direction indicates the counter output direction of the pneumatic booster (right direction in the drawing). It is.

In the figure, reference numeral 1 denotes a pneumatic booster, which has a shell 2. The shell 2 includes a front shell 4 in which a master cylinder (not shown) is mounted outside the end face portion 3 on the output direction side, and a rear shell 5 which is fitted airtightly on the opposite side of the front shell 4 in the output direction. The rear shell 5 has a seal / support member 7 made of an elastic material in a fitting hole 6 formed at the end on the opposite side to the output direction, and the power piston 8 slides on the seal / support member 7. It is freely supported.

The power piston 8 has a flange portion 9 located in the shell 2 and a large-diameter portion 10 having a diameter slightly smaller than the flange portion 9 provided on the side opposite to the output direction of the flange portion 9 and supported by the seal and support member 7. A stepped bottomed cylindrical valve body portion 12 comprising a large-diameter portion 10 and a small-diameter portion 11 having a predetermined diameter smaller than the large-diameter portion 10 and protruding to the outside of the shell, and a flange portion. A perforated disk-shaped plate portion 13 whose inner peripheral side is fixed to the inner peripheral side and extends radially outward, and is provided on the opposite side to the output direction of the plate portion 13 and the inner peripheral portion is hermetically supported by the flange portion 9. And a partition member 14 made of an elastic material whose outer peripheral portion is hermetically supported by the shell 2. Thus, the inside of the shell 2 is airtightly connected to a negative pressure chamber 16 on the output direction that communicates with a negative pressure source (not shown) through the negative pressure communication pipe 15 and a working pressure chamber 17 on the opposite output direction. It is partitioned.

The other end of the operating rod 18 connected to a brake pedal (not shown) is inserted into the opening of the valve body 12 on the side of the small diameter portion 11. An elastically deformable poppet valve 21 is provided on the direction side via springs 19 and 20, and a valve plunger 22 arranged in series with the poppet valve 21 is engaged with the tip of the poppet valve 21. Also, the valve plunger 22
On the output direction side, an output shaft 24 is provided via a reaction disk 23 made of an elastic material having a larger diameter than this, and the output shaft 24 is inserted into a front seal 26 through an insertion hole 25 provided in the front shell 4. When the power piston 8 moves in the output direction, the power is output toward a master cylinder (not shown) by the power piston 8 moving in the output direction. Further, a return spring 27 is provided between the front shell 4 and the power piston 8 for urging the power piston 8 in a counter-output direction with a predetermined urging force. Movement is
The limit position is regulated by contacting the protrusion 28 formed on the rear shell 5.

The valve body 12 has a negative pressure passage 29 communicating with the negative pressure chamber 16 and a working passage 32 communicating with the working pressure chamber 17. The poppet valve 21 is
The communication between the negative pressure flow path 29 and the operation flow path 32 is shut off by sitting on a contact part 31 formed at the bottom of the valve body part 12 (a valve constituted by the poppet valve 21 and the contact part 31). Negative pressure valve 30) and the valve body 12
The communication between the opening side of the valve and the working channel 32 is performed by the valve plunger 2.
2 is shut off by sitting on the end on the side opposite to the output direction (the valve constituted by the poppet valve 21 and the valve plunger 22 is referred to as an atmospheric valve 33).

When the power piston 8 is in a non-operating state and is at the movement limit position in the counter-output direction, the poppet valve 21 opens the negative pressure valve 30 and closes the atmosphere valve 33, that is, closes the operating pressure chamber 17. It is in a state of communicating with the negative pressure chamber 16. Then, when an input is made to the operating rod 18 and the operating rod 18 and the valve plunger 22 move relative to the valve body 12 in the output direction, first, the abutting part 31 of the valve body 12 is brought into contact, and the negative pressure valve 30 is closed. The communication between the working pressure chamber 17 and the negative pressure chamber 16 is cut off, and then the movement is regulated by the contact part 31, so that the working pressure chamber 17 is separated from the moving valve plunger 22, and the working pressure chamber 17 is opened. It is designed to communicate with In this state, the input of the operating rod 18 is loosened, and the valve plunger 22 and the operating rod 18 are moved to the valve body 12 by the reaction force transmitted from the master cylinder (not shown) via the output shaft 24 and the reaction disk 23. On the other hand, when the relative movement is made in the opposite direction to the output direction, first, it comes into contact with the valve plunger 22 to close the atmosphere valve 33,
Next, the negative pressure valve 30 is opened by separating from the contact part 31 of the valve body part 12.

The valve plunger 22 is formed with a groove 35 having a width larger than the stopper plate 34 by a predetermined amount for locking one end of a stopper plate 34 having a predetermined width extending in the orthogonal direction. The other end of the plate 34 is formed in the large diameter portion 10 of the valve body 12 and has a groove 3 having a width larger than the stopper plate 34 by a predetermined amount.
6, the range of relative movement of the valve plunger 22 with respect to the valve body 12 is restricted by the stopper plate 34. The groove 36 forms a part of the working channel 32.

In the first embodiment, a cover 37 having an outermost diameter substantially the same as that of the rear shell 5 is hermetically fixed to the rear shell 5 on the output side outside the valve body portion 12 protruding from the rear shell 5. It is provided in a state where it is set. The cover 37 has a shape having three cylindrical portions whose diameters gradually decrease along the non-output direction, and the cover 37 has elastic holes formed in fitting ends 38 formed at the end on the non-output direction side. A seal / support member 39 made of a material is provided, and the small diameter portion 11 of the valve body 12 is slidably supported by the seal / support member 39. The cover 37 is provided with a communication pipe 43 connected via an external pipe 42 to an air pump 41 that is a compressed air source that generates compressed air by driving a motor 40. The space defined by the rear shell 5 constitutes a compressed air chamber 44 filled with compressed air. Here, the external pipe 42 is provided with a check valve 45 for preventing the compressed air from flowing back toward the air pump 41.

The compressed air chamber 44 or the external pipe 42
A pressure sensor (not shown) is provided on the side of the compressed air chamber 44 from the check valve 45, and a control unit (not shown) uses a signal from the pressure sensor to increase the pressure in the compressed air chamber 44 from the atmospheric pressure. The drive of the motor 40 is controlled so as to always maintain a high predetermined value.

A part of the working flow path 32 on the side of the valve body 12 on the output side of the groove 36 is connected to the working pressure chamber 17 at one end, and an opening is provided outside the working flow path 32. Flow path 4 for communicating the compressed air chamber 44 with the groove 36
7 has an opening at one end. On the side surface on the output direction side of the stopper plate 34, a recess 49 is formed which is recessed one step so as to face a range including both openings, and the stopper plate 34 is formed on the side surface 46 of the valve body 12.
A seal ring 50 made of an elastic material is fitted to the outside of the concave portion 49.

A valve chamber 51 is provided in the flow passage 47. The valve chamber 51 is provided with a projection 52 provided so as to protrude from the opening facing the recess 49 toward the groove 36 side. Room 5
1. A valve body 55 comprising a valve portion 54 seated on the seating portion 53 on the side opposite to the output direction and closing the flow path 47, and the valve portion 54 provided on the output direction side of the valve body 55 is attached to the seating portion 53. An on-off valve 57 including a spring 56 for urging the valve body 55 to be seated is provided. After the stopper plate 34 moves to the vicinity of the movement limit position in the output direction with respect to the valve body 12 and abuts on the seal ring 50, the projection 52 abuts on the bottom surface of the concave portion 49. The valve 34 is pressed by the movement of the plate 34 and moves against the urging force of the spring 56 to separate the valve portion 54 from the seating portion 53 and open the flow path 47.

The relationship between the input to the operating rod 18 and the reaction force from the return spring 27 and the master cylinder (not shown) is such that the depressing force for obtaining the normal deceleration is input to the brake pedal. In this case, the valve body 12 of the operating rod 18 is
Is set so as to be a predetermined range in which the stopper plate 34 does not contact the seal ring 50 and does not open the on-off valve 57. Further, in order to obtain a larger deceleration after a stepping force for obtaining a rapid deceleration is input to the brake pedal (during a so-called spike brake) and after a full load point (a point where the working pressure chamber 17 becomes the atmospheric pressure). When the brake pedal is depressed,
When the relative movement position of the operating rod 18 with respect to the valve body 12 exceeds the above-described predetermined range and reaches the vicinity of the movement limit position, the stopper plate 34
And the opening / closing valve 57 is opened.

In the pneumatic booster 1 according to the first embodiment having the above-described configuration, the negative pressure valve 30 is opened and the atmospheric valve 33 is closed in a non-operating state in which a brake pedal (not shown) is not depressed. When a brake pedal is depressed to obtain a normal low deceleration from this state, the operating rod 18 connected to the brake pedal is depressed.
The valve plunger 22 moves relative to the valve body 12 in the output direction within the predetermined range. Then
The poppet valve 21 first contacts the contact portion 31 of the valve body 12 to close the negative pressure valve 30, and then the valve plunger 22 separates from the poppet valve 21 and the atmospheric valve 33.
Is opened, the working flow path 32 is communicated with the opening side of the valve body part 12 to introduce the atmosphere into the working pressure chamber 17, and a differential pressure is generated on both sides of the plate part 13 of the power piston 8 to input the operating rod 18. Is output from the output shaft 24 to the master cylinder (not shown).

During the brake operation or when the brake is not operated, the operating rod 18 and the valve plunger 22 exceed the predetermined range in the output direction with respect to the valve body 12 in order to obtain a sudden deceleration that cannot be normally obtained. When the brake pedal is depressed with a large force that relatively moves until it reaches the vicinity of the movement limit position, the negative pressure valve 30 is closed and the atmospheric valve 33 is opened as described above, or the negative pressure valve 30 is closed and the atmospheric valve 33 is closed. Is opened, the stopper plate 34 locked by the valve plunger 22 comes into contact with the seal ring 50 and the working flow path 32
While blocking the communication with the valve body 55, the valve body 55 comes into contact with and presses the projection 52 of the valve body 55, and separates the valve portion 54 from the seating portion 53.
Open 7. Then, the flow path 47, the stopper plate 34
The compressed air chamber 44 and the working pressure chamber 17 communicate with each other through a space surrounded by the seal ring 50 and a part of the closed working passage 32 on the side of the working pressure chamber 17, and compress the compressed air to the working pressure. It will be introduced into the chamber 17. As a result, a differential pressure is generated in the power piston 8 at a speed faster than the introduction of the normal atmosphere. The flow path 47 formed in the valve body 12, the space, and the blocked operation flow path 3
A part of the second working pressure chamber 17 side constitutes a flow path connecting the compressed air chamber 44 and the working pressure chamber 17, and the flow path, the compressed air chamber 44 and the external pipe 42 are connected to each other by a compressed air source. And a flow path for connecting the air pump 41 and the working pressure chamber 17.

Further, a brake operation is performed to obtain a normal deceleration, and when the working pressure chamber 17 reaches the atmospheric pressure (full load point), the brake pedal is depressed to obtain a larger deceleration, and the operating rod is depressed. When the valve 18 and the valve plunger 22 move in the output direction with respect to the valve body 12 beyond the predetermined range to near the movement limit position, the negative pressure valve 30 is closed and the atmospheric valve 33 is opened as described above. The stopper plate 34 locked by the plunger 22 abuts against the projection 52 of the valve body 55 and presses it while contacting the seal ring 50 to cut off the communication of the working flow path 32, thereby seating the valve portion 54. The compressed air chamber 44 and the working pressure chamber 17 are communicated with each other by opening the flow path 47 away from the part 53, and the compressed air is introduced into the working pressure chamber 17. As a result, the pressure in the working pressure chamber 17 increases until it exceeds the atmospheric pressure and becomes substantially the same as the pressure in the compressed air chamber 44, and a larger differential pressure acts on the power piston 8.

Of course, in order to obtain a rapid deceleration, the brake pedal is depressed with a large force that moves the operating rod 18 and the valve plunger 22 in the output direction beyond the predetermined range to the vicinity of the movement limit position with respect to the valve body 12. If it continues, the stopper plate 34
Keeps the on-off valve 57 in the open state, the compressed air continues to be introduced into the working pressure chamber 17, so that the pressure in the working pressure chamber 17 rises by a large amount and exceeds the atmospheric pressure and exceeds the atmospheric pressure. The pressure rises to approximately the same pressure as the pressure in the air chamber 44.

According to the pneumatic booster 1 of the first embodiment, when the ordinary low deceleration is to be obtained, the atmosphere is introduced into the working pressure chamber 17 without opening the on-off valve 57. In this case, the response of the brake does not become excessively sensitive, and when it is intended to obtain a sudden deceleration that cannot be normally obtained, the open / close valve 57 is opened and the compressed air is supplied to the working pressure chamber 17. As a result, a differential pressure is generated in the power piston 8 at a speed faster than the introduction of the normal atmosphere.
The amount of boosting support increases. Therefore, the response is excellent.

In order to obtain a larger deceleration when the working pressure chamber 17 reaches the atmospheric pressure, the on-off valve 57 is opened and compressed air is introduced into the working pressure chamber 17. As a result, the pressure in the working pressure chamber 17 exceeds the atmospheric pressure, and a larger differential pressure acts on the power piston 8. Therefore, it is possible to increase the assisting force and increase the upper limit of the boosting action without increasing the size.

Further, the valve body portion 12 is supported by the shell 2 at the large diameter portion 10 and the small diameter portion 11
Is also supported by the cover 37, so that the support is more stable. Moreover, the compressed air chamber 44 defined by the cover 37 and the shell 2 is filled with compressed air, and a flow path for connecting the compressed air chamber 44 and the working pressure chamber 17 is provided in the valve body 12. Since the on-off valve 57 is provided in the flow path, the flow path for introducing compressed air into the working pressure chamber 17 is shortened, and the responsiveness is further improved.

Next, a pneumatic booster according to a second embodiment of the present invention will be described below with reference to FIGS. 2 and 3 focusing on parts different from the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

In the pneumatic booster 1 of the second embodiment, the valve body 12 of the power piston 8 has a stepped shape comprising the flange portion 9 on the output side and the small diameter portion 11 on the opposite side to the output side. The small diameter portion 11 is slidably supported by the seal / support member 7 of the rear shell 5. Also, cover 3
Reference numeral 7 denotes a shape having two cylindrical portions whose diameters decrease in the non-output direction, and the small-diameter portion 1 of the valve body 12 is attached to the seal / support member 39 at the end on the non-output direction side.
1 is slidably supported.

As shown in FIG. 3, a substantially U-shaped stopper plate 34 is engaged with the valve plunger 22, and seal members 60 and 61 are provided on both sides of a groove 35 for engaging the stopper plate 34. Is provided. These seal members 60 and 61 allow the air in the compressed air chamber 44 to be formed on the outer peripheral side of the valve plunger 22 through a hole 62 formed through the compressed air chamber 44 in the valve body 12 to insert the stopper plate 34. A part of the working channel 32 is formed in the valve plunger 22 in such a manner that both end openings 63 and 64 are provided on both outer sides of the seal members 60 and 61, respectively, to prevent leakage through the gap. The opening 64 on the output direction communicates with the working pressure chamber 17 via a through hole 32 a formed at the bottom of the valve body 12 and forming a part of the working flow path 32.

An annular groove 65 is formed on the output direction side of the valve plunger 22 further from the opening 64 on the output direction side. In an energized state, an elastically deformable annular valve portion that abuts against an annular convex portion 65a formed on an end face on the output direction side of the annular groove portion 65 and airtightly partitions a space 68 in the annular groove portion 65 from the outside. 67 is provided so as to partially protrude outward in the radial direction. The space 68 inside the annular valve portion 67, the groove 35, and the hole 62 are provided.
Are communicated with each other by a flow path 69 formed in the valve plunger 22. Further, the valve body portion 12 comes into contact with the annular valve portion 67 by the movement of the valve plunger 22 when a brake pedal (not shown) is depressed so as to obtain a sudden deceleration that cannot be normally obtained. Regulates
A regulating portion 70 for separating the annular valve portion 67 from the annular convex portion 65a of the annular groove portion 65 is provided so as to protrude radially inward. The annular valve portion 67 and the spring 66 constitute the on-off valve 71 in the second embodiment.

The position of the movement limit of the power piston 8 on the side opposite to the output direction is regulated by the stopper plate 34 abutting on the cover 37. In this state, both the atmosphere valve 33 and the negative pressure valve 30 are closed. It is in a state of being left. When an input is made from the brake pedal, the atmospheric valve 33 is opened by the relative movement of the operating rod 18 in the output direction, and when the brake pedal is released, the atmospheric valve 33 is released by the relative movement of the operating rod 18 in the opposite output direction. After the valve 33 is closed, the negative pressure valve 30 is opened, and the working pressure chamber 17 and the negative pressure chamber 16 have substantially the same pressure.
The two pressures are balanced so that the negative pressure valve 30 is closed.

In the pneumatic booster 1 according to the second embodiment having the above-described structure, the negative pressure valve 30 and the atmospheric valve 33 are both closed when the brake pedal is not depressed. When the brake pedal is depressed to obtain a normal low deceleration, the operating rod 18 and the valve plunger 22 connected to the brake pedal move relative to the valve body 12 in the output direction within a predetermined range. Then, the valve plunger 2
2 is separated from the poppet valve 21, opens the atmosphere valve 33, connects the working channel 32 to the opening side of the valve body 12, introduces air into the working pressure chamber 17, and
A differential pressure is generated on both sides of the plate portion 13 to assist the input of the operating rod 18 and output from the output shaft 24 to the master cylinder (not shown).

During the brake operation or when the brake is not operated, the operating rod 18 and the valve plunger 22 move beyond the predetermined range in the output direction with respect to the valve body 12 in order to obtain a sudden deceleration which cannot be normally obtained. When the brake pedal is depressed with a large force to move to the vicinity of the movement limit position, the valve plunger 22
The movement is regulated in a state where the annular valve portion 67 provided on the output direction side of the valve body abuts on the regulating portion 70 of the valve body portion 12 to interrupt the communication of the working flow path 32. Then, by further movement of the valve plunger 22, the annular valve portion 67 contracts against the urging force of the spring 66, moves away from the annular convex portion 65a of the annular groove portion 65, opens the space portion 68, and opens the hole portion 6
2. The compressed air chamber 44 is formed in a part of the groove 35, the flow path 69, the space 68, and the closed operation flow path 32 on the side of the operation pressure chamber 17
And the working pressure chamber 17 and communicate compressed air to the working pressure chamber 17.
Will be introduced. The hole 62 and the groove 3
5, the flow path 69, the space 68, and the blocked operation flow path 3
A part of the second working pressure chamber 17 side constitutes a flow path connecting the compressed air chamber 44 and the working pressure chamber 17, and the flow path, the compressed air chamber 44 and the external pipe 42 are connected to each other by a compressed air source. And a flow path for connecting the air pump 41 and the working pressure chamber 17.

Further, a brake operation is performed to obtain a normal deceleration, and when the working pressure chamber 17 becomes the atmospheric pressure (full load point), the brake pedal is depressed to obtain a further deceleration, and the operating rod is depressed. When the valve 18 and the valve plunger 22 move in the output direction with respect to the valve body 12 beyond the above-described predetermined range to near the movement limit position, the annular valve portion 67 provided on the output direction side of the valve plunger 22 moves The movement is regulated in a state where the contact with the regulating section 70 is interrupted and the communication of the working flow path 32 is interrupted. Then, by further movement of the valve plunger 22, the annular valve portion 67 contracts against the urging force of the spring 66, separates from the annular convex portion 65a of the annular groove portion 65, opens the space portion 68, and opens the compressed air chamber 44. Is communicated with the working pressure chamber 17, and compressed air is introduced into the working pressure chamber 17.

Of course, in order to obtain a rapid deceleration, the brake pedal is depressed with a large force to move the operating rod 18 and the valve plunger 22 in the output direction beyond the predetermined range to the vicinity of the movement limit position with respect to the valve body 12. If this continues, the on-off valve 71 continues to maintain the open state, so that the compressed air continues to be introduced into the working pressure chamber 17, and therefore the pressure in the working pressure chamber 17 rises by a large amount and exceeds the atmospheric pressure. The pressure rises to almost the same pressure as the pressure of the compressed air chamber 44 higher than the atmospheric pressure.

According to the pneumatic booster 1 of the second embodiment, the same effects as those of the first embodiment can be obtained, and of course, the valve plunger 22 disposed in series on the output side of the poppet valve 21 can be used. Further, the on-off valve 71 is connected in series on the output direction side.
Is provided, it is not necessary to enlarge the valve body portion 12 in the radial direction. Therefore, the force that the valve body portion 12 receives from the compressed air chamber 44 can be reduced, and the spring load of the return spring 27 can be reduced. Can be.

In each of the first and second embodiments, when the operating rod 18 and the valve plunger 22 are relatively moved with respect to the valve body 12 near the movement limit position in the output direction, the on-off valve 5
Although the configuration is such that the openings 7 and 71 are opened, the opening is not necessarily required near the movement limit position as long as the opening is opened when the relative movement exceeds a predetermined range for obtaining the above-described normal low deceleration.

[0041]

As described in detail above, claim 1 of the present invention
According to the described pneumatic booster, when trying to obtain a normal low deceleration, the atmosphere is introduced into the working pressure chamber, so that the brake reaction does not become overly When attempting to obtain a rapid deceleration that does not occur, the on-off valve is opened and compressed air is introduced into the working pressure chamber, so a differential pressure is generated at the power piston at a speed faster than normal air introduction. In other words, the amount of increase in the assisting force increases. Therefore, the response is excellent. Further, if an attempt is made to obtain a larger deceleration when the working pressure chamber reaches the atmospheric pressure, the on-off valve is opened and compressed air is introduced into the working pressure chamber. Since the pressure in the pressure chamber exceeds the atmospheric pressure and a larger differential pressure acts on the power piston, the supporting force can be increased and the upper limit of the boosting action can be increased without increasing the size. further,
Opening / closing valve is operating lock for valve body
It opens and closes according to the relative amount of movement of the
Therefore, no pressure switch is required. Plus compressed air
Source and working pressure chamber without poppet valve
Since the on-off valve is provided in the flow path, when the on-off valve is opened
The amount of compressed air to be introduced into the
Free setting regardless of the set poppet valve opening
Can be specified.

According to the pneumatic booster of the second aspect of the present invention, in addition to the effect of the first aspect, the on- off valve is provided by an operating valve of a poppet valve.
The valve is installed in series on the output side of the
Since there is no need to enlarge the radial direction of the body, the valve
The body receives less force from compressed air.
And reduce the spring load of the return spring
You.

Furthermore, according to the pneumatic booster of the third aspect of the present invention, the valve body is supported by the shell and also by the cover, so that the support of the valve body is stabilized. Become. Moreover, since the compressed air chamber defined by the cover and the shell is filled with compressed air, and the compressed air chamber is connected to the working pressure chamber via the valve by a flow path provided in the valve body, There is no need to configure the compressed air chamber as a separate tank from the pneumatic booster, which eliminates the need for piping work and shortens the compressed air introduction path to the working pressure chamber.
Its operation response is also improved. In addition, claim 4 of the present invention
According to the described pneumatic booster, a normal low deceleration is obtained.
If this is the case, the atmosphere will be introduced into the working pressure chamber.
The brake response is not too sensitive and can usually be
If a sharp deceleration is to be obtained, open and close the valve.
Power piston because compressed air is introduced into the working pressure chamber
Tons develop differential pressure faster than normal atmospheric introduction
As a result, the amount of increase in the assisting force increases. Therefore,
The answer will be excellent. Also, the working pressure chamber reaches atmospheric pressure
If you try to get a larger deceleration at the time
Opens the open / close valve and introduces compressed air into the working pressure chamber
As a result, the pressure in the working pressure chamber is reduced to the atmospheric pressure.
The power piston
To increase the supporting force without increasing the size.
However, the upper limit of the boosting action can be increased. further,
Opening / closing valve is operating lock for valve body
It opens and closes according to the relative amount of movement of the
Therefore, no pressure switch is required. In addition, the on-off valve
Blocks air from entering the working pressure chamber via the poppet valve
And a flow path for connecting the compressed air source to the working pressure chamber.
To be introduced when the on-off valve is opened
Poppet with air volume set for introduction of air
Can be set freely regardless of the valve opening amount
You.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a pneumatic booster according to a first embodiment of the present invention, showing a non-operating state.

FIG. 2 is a cross-sectional view showing a pneumatic booster according to a second embodiment of the present invention, showing a non-operating state.

FIG. 3 is a partially enlarged cross-sectional view showing the vicinity of an on-off valve of a pneumatic booster according to a second embodiment of the present invention, showing a non-operating state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Atmospheric pressure booster 2 Shell 8 Power piston 12 Valve body 16 Negative pressure chamber 17 Working pressure chamber 18 Operating rod 21 Poppet valve 37 Cover 41 Air pump (compressed air source) 44 Compressed air chamber 57, 71 Open / close valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-134047 (JP, A) JP-A-1-145257 (JP, A) JP-A-54-9365 (JP, A) 194954 (JP, U) Japanese Utility Model Showa 59-142159 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 13/52-13/57

Claims (4)

(57) [Claims] A power piston for partitioning the inside of a shell into a negative pressure chamber and an operating pressure chamber communicating with a negative pressure source, and a valve body slidably supported at one end of the shell; A poppet valve that is provided in the body portion and that introduces air into the working pressure chamber by relative movement of an operating rod connected to a brake pedal in an output direction with respect to the valve body portion, and introduces air into the working pressure chamber. In the pneumatic booster that generates a differential pressure in the power piston to assist the output of the operating rod and output the compressed air, a compressed air source for generating compressed air, the compressed air source and the working pressure chamber And the poppet valve
A flow path to be connected without intervening; and a valve provided in the flow path, the valve closing when the relative movement amount of the operating rod in the output direction with respect to the valve body does not reach a predetermined value, and closing the valve in the output direction. An on-off valve that opens when the amount of movement reaches a predetermined value. 2. The on-off valve according to claim 1, wherein
The pneumatic booster according to claim 1, wherein the pneumatic booster is provided in series on the output direction side of the operating rod. 3. A power piston which partitions the inside of the shell into a constant pressure chamber and a working pressure chamber and has a valve body slidably supported at one end of the shell, and a brake provided in the valve body. A valve for introducing a working gas into the working pressure chamber by a relative movement of an operating rod connected to a pedal with respect to the valve body in an output direction, and introducing the working gas into the working pressure chamber to thereby provide the power piston. A pressure booster that generates a differential pressure to assist the output of the operating rod and outputs the compressed air. The compressed air source that generates compressed air as the working gas, and protrudes from the shell of the valve body. The valve body portion is slidably supported on the outside of the portion, connected to the compressed air source, and A cover defining a compressed air chamber filled with compressed air together with the shell is provided, and the compressed air chamber is connected to the working pressure chamber via the valve by a flow path provided in the valve body. Pneumatic booster. 4. A negative pressure chamber communicating with a negative pressure source inside the shell.
It is divided into a dynamic pressure chamber and one end of the shell.
Power piston with slidably supported valve body
And a brake pedal provided in the valve body.
The valve of the operating rod connected to the dal
The relative pressure in the output direction with respect to the body
A poppet valve for introducing air into the chamber,
The powerpist is introduced by introducing air into the dynamic pressure chamber.
Pressure differential to the operating rod
In a pneumatic booster that assists and outputs force, a compressed air source for generating compressed air, a flow path connecting the compressed air source and the working pressure chamber, and the valve provided in the flow path, The above-mentioned o for the body part
Predetermined relative movement amount of the operating rod in the output direction
Actuation via the poppet valve when the value is reached
Opening and closing to shut off the introduction of air to the pressure chamber and communicate with the flow path
A pneumatic booster comprising: a valve .