JPH1029529A - Vacuum boost system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To still operational sounds from solenoid valves in a vacuum boost system to the utmost and facilitate the fitting of a vacuum booster and the solenoid valves and the connection of pipes into the system. SOLUTION: A manifold plate 34 integrally includes charging passages 39 and 42, a first normally-open solenoid switch valve for opening or closing the charging passages 39 and 42, a chamber-connecting passage which interconnects a constant-pressure chamber 9 and a variable-pressure chamber 10 without utilizing a control valve 23, and a second normally-closed solenoid switch valve for opening or closing the chamber-connecting passage. The manifold plate 34 is integrally incorporated in a vacuum booster 1 to form a unit. The unit is fitted on a separation wall 51 so as to be positioned inside an engine room R1 and to take air of the atmospheric pressure therein from the inside of an operation room R2 . As a result of which, the fitting of the unit is facilitated, operation sounds from the solenoid valves are stilled in the operation room R2 , and clean air in the operation room R2 is lead into the vacuum booster 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a negative pressure boosting system for increasing a brake force by boosting the depression force of a brake pedal by a negative pressure in, for example, an automobile. The present invention belongs to the technical field of a vacuum booster system that variably controls the output by controlling the introduction of the negative pressure and the atmosphere to the vacuum booster.

[0002]

2. Description of the Related Art Conventionally, for example, in a brake system of an automobile, a negative pressure booster system provided with a negative pressure booster for increasing a braking force by boosting and outputting a depression force of a brake pedal by a negative pressure is known. is there.

In a negative pressure booster system provided with such a negative pressure booster, antilock brake control (hereinafter referred to as ABS) for adjusting the braking force so as to eliminate the tendency of the brake wheels to lock when the brake wheels tend to lock. Control)
Anti-lock brake control system (hereinafter referred to as AB
S) is proposed in, for example, Japanese Utility Model Laid-Open No. 2-125879.

[0004] The vehicular braking system disclosed in this publication discloses an electromagnetic switching valve, which is provided on the brake pedal side of a vacuum booster and through which a passage for introducing the atmosphere into a variable pressure chamber is controlled by a controller. Thus, the connection is switched to the atmosphere or a negative pressure source.

[0005] Therefore, in the vehicular braking system constructed as described above, the passage is normally connected to the atmosphere by the electromagnetic switching valve, and when the brake pedal is depressed, the negative pressure booster is operated, and the normal pressure is applied to the wheels. I can brake. When the brake wheels tend to lock during braking, the electromagnetic switching valve is switched to shut off the passage from the atmosphere and connect to the negative pressure source. As a result, the pressure in the transformation chamber is reduced, the output of the negative pressure booster is reduced, and the braking force is weakened. When the locking tendency is eliminated, the electromagnetic switching valve is switched back to the original position, and the passage is disconnected from the negative pressure source and connected to the atmosphere. As a result, air is introduced into the transformer chamber, and its pressure increases,
The output of the negative pressure booster increases and the braking force is increased. Thus, the ABS control is performed when the wheels tend to lock.

[0006]

Incidentally, in such an ABS, a passage for introducing the atmosphere into the transformer chamber is provided on the brake pedal side of the vacuum booster, and the vacuum booster is provided. The rear shell that forms the transformer room is designed to be attached to the bulkhead of the car body that blocks the cab and the engine room, and because the air in the cab is more clean than the engine room, The electromagnetic switching valve has to be arranged on the cab side.

However, disposing the electromagnetic switching valve in the operator's cab as described above has a problem in that the operating noise generated when the electromagnetic valve operates is noisy for the driver. Also, after installing the vacuum booster on the bulkhead of the vehicle body on the engine room side, it is necessary to install the electromagnetic switching valve and connect the pipes through which air flows on the cab side. Due to the small space, there is a problem that these operations are extremely difficult. Further, since an installation space for the electromagnetic switching valve is required around the brake pedal, there is a problem that the degree of freedom of installation is restricted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make the operation sound of a solenoid valve as quiet as possible and to mount a negative pressure booster and a solenoid valve. An object of the present invention is to provide a negative pressure booster system that can simplify operations and pipe connection operations.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a front shell and a rear shell which form an internal space, a constant-pressure chamber which is always connected to the negative pressure source with the internal space. A power piston that is partitioned into a transformer chamber into which air at atmospheric pressure is introduced during operation, and operates by a pressure difference between the transformer chamber and the constant-pressure chamber to generate an output; A control valve consisting of an atmospheric valve for controlling the introduction and a communication between the variable pressure chamber and the constant pressure chamber, a vacuum valve for controlling the shutoff, and a forward movement by operating the brake operating member and a backward movement by releasing the operation of the brake operating member. A negative pressure booster including at least an input shaft for controlling the operation of the control valve; an air supply passage attached to the rear shell for introducing the atmospheric pressure air to the atmospheric valve; and the air supply passage. Established in A first solenoid valve which is normally open for controlling the opening and closing of the supply passage; an inter-room connection passage which communicates the constant pressure chamber and the variable pressure chamber without passing through the control valve; A manifold plate provided with a normally closed second solenoid valve that controls opening and closing of the inter-room connection passage, wherein the negative pressure booster and the manifold plate are integrally assembled to form a unit, This unit is characterized in that it is attached to a partition wall that blocks between the engine room and the driver's cab from the engine room side such that the open end of the air supply passage faces the driver's cab.

According to a second aspect of the present invention, a hole is formed in the partition wall so as to penetrate between the surface on the engine room side and the surface on the driver cab side, and a part of the unit is formed in the hole. And extending into the cab through the hole so as to form an annular air supply passage therebetween, and that the open end of the air supply passage faces the annular air supply passage. Features.

The invention according to claim 3 is characterized in that the open end of the air supply passage is formed in an arc shape along the annular air supply passage. Further, the invention according to claim 4 is characterized in that a filter is provided at an open end of the air supply passage.

[0012]

According to the present invention having the above-described structure, the manifold plate integrally incorporating the air supply passage, the inter-chamber connection passage, and the first and second solenoid valves is assembled to the negative pressure booster to form a unit. It is formed. The unit is mounted on the partition of the vehicle body so as to be located in the engine room and to allow air at atmospheric pressure to be taken in from the cab. Therefore, after the unit is mounted on the partition, only the operation of electrically connecting the first and second solenoid valves is performed, and the operation is completed. Therefore, the mounting work of the negative pressure booster and the respective solenoid on-off valves becomes extremely easy, and the working space is not required to be so large.

Further, since the first and second solenoid valves are both located in the engine room, the operating sound of each solenoid on-off valve becomes quiet in the cab. Moreover, even if both the first and second solenoid valves are arranged in the engine room,
The air at atmospheric pressure introduced into the vacuum booster is taken in from the cab. Therefore, unlike the air in the engine room, clean air is introduced into the negative pressure booster.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a negative pressure booster system according to the present invention.

As shown in FIG. 1, the vacuum booster system of the present embodiment includes a vacuum booster 1.
Has a front shell 2 and a rear shell 3 connected to each other by, for example, bayonet connection.

The front shell 2 and the rear shell 3
The valve body 4 is disposed so as to penetrate the rear shell 3 between the inside and the outside of the space formed by the valve body 4, and the valve body 4 is more airtight and sealed by the rear shell 3 and the seal member 5. It is slidably supported. A power piston member 6 disposed in the space inside the shells 2 and 3 is connected to the valve body 4. Shells 2 and 3 and valve body 4 are provided on the back of power piston member 6.
A diaphragm 7 is provided between the two. A power piston 8 is constituted by the power piston member 6 and the diaphragm 7, and the space inside the shells 2 and 3 is partitioned into a constant pressure chamber 9 and a variable pressure chamber 10 by the power piston 8.

The valve body 4 is formed with a concave fitting portion 11 which opens into the constant pressure chamber 9, and a bottom portion of the concave fitting portion 11 is formed with a projecting portion 4a whose central portion projects toward the constant pressure chamber 9. ing. At the approximate center of the projecting portion 4a, the concave fitting portion 1
1, a second hole 13, a third hole 14, a fourth hole 15 and a valve are connected to the first hole 12 in a rearward (rightward direction in the drawing) order. Fifth holes 16 are formed in the rear end of the body 4. Further, the constant pressure chamber 9 and the fourth hole 15 are provided in the valve body 4.
And an axial passage 17 communicating therewith.

A valve plunger 18 is slidably fitted in the first hole 12 and the second hole 13 of the valve body 4. An input shaft 19 linked to a brake pedal (not shown) is connected to the right end of the valve plunger 18. A radial hole 20 is formed in the valve body 4 so as to be orthogonal to the second hole 13, and a key member 21 is fitted through the hole 20 to the valve plunger 18 so as to be relatively movable in the axial direction. ing. In addition, the key member 21 can move in the axial direction by the width of the hole 20 together with the valve plunger 18, and the key member 21 prevents the valve plunger 18 from coming out of the valve body 4. Further, a passage 22 is formed in the valve body 4 so as to open to the variable pressure chamber 10 so as to be orthogonal to the second hole 13. This passage 22 also communicates with the third hole 14.

A control valve 23 is provided in the fifth hole 16 of the valve body 4. The control valve 23 is attached to the valve body 4 and is constantly urged in the direction of the valve plunger 18 by the resilient force of a spring 24 interposed between the valve body 25 and the input shaft 19. And a second valve seat 27 formed in the valve body 4. When the valve body 25 is seated on the first valve seat 26 and separated from the second valve seat 27, the control valve 23 communicates the constant-pressure chamber 9 with the variable-pressure chamber 10 and connects the variable-pressure chamber 10 with the atmosphere. The communication is cut off, and the valve body 25 is separated from the first valve seat 26 and the second valve seat 2
When the vehicle is seated at 7, the communication between the constant pressure chamber 9 and the variable pressure chamber 10 is cut off, and the switching control is performed so that the variable pressure chamber 10 and the atmosphere are communicated. Therefore,
The valve body 25 and the first valve seat 26 constitute an atmosphere valve for controlling the introduction of the atmosphere, and the valve body 25 and the second valve seat 27 constitute a vacuum valve for controlling the introduction of vacuum. .

A large-diameter portion at the right end of the output shaft 28 is provided in the concave fitting portion 11 of the valve body 4, and a concave portion formed in the large-diameter portion at the right end slides on the projecting portion 4 a of the valve body 4. They are freely fitted. A reaction disk 29 is accommodated between the output shaft 28 and the protruding portion 4a of the valve body 4 in the concave portion at the right end large diameter portion. A spacer 30 and a predetermined gap are interposed between the valve plunger 18 and the reaction disk 29.

The output shaft 28 is prevented from falling out of the valve body 4 by a retainer 32 urged rightward by a return spring 31 for returning the valve body 4 to the inoperative position. The left end of the output shaft 28 is linked to a piston (not shown) of a master cylinder M shown in FIG.

The valve body 4 and each of the power pistons 8 connected thereto are normally held in the inoperative position shown by a return spring 31. In this non-operating state, the key member 21 abuts on the inner surface of the rear shell 3 to regulate the rightward movement of the valve plunger 18 and hold the valve plunger 18 at the retreat limit position. When the input shaft 19 is not operated, the key member 21 is connected to the valve body 4.
At this time, the valve body 25 is seated on both the first valve seat 26 and the second valve seat 27 at this time, and the variable pressure chamber 10 is connected to both the atmosphere and the constant pressure chamber 9. It is shut off. Therefore, during braking, as soon as the valve plunger 18 is actuated by the advancement of the input shaft 19, the valve body 2
5 and the first valve seat 26 are separated from each other, so that the transformer chamber 10 and the atmosphere are immediately communicated with each other.

The constant pressure chamber 9 is always in communication with a negative pressure source such as an engine intake manifold (not shown) through a negative pressure introducing pipe 33 attached to the front shell 2. Therefore, a negative pressure is always introduced into the constant pressure chamber 9.

Further, on the rear surface of the rear shell 3 of the negative pressure booster 1, a manifold plate 34 is fixed by bolts 35 and nuts 36 to a sealing member 3 such as a gasket.
7 are fixed. As shown in FIG. 2, the manifold plate 34 has a semi-circular concave fitting portion 38 opened on a surface opposite to the rear shell 3, a first air supply passage 39 communicating with the concave fitting portion 38, As shown in FIG. 3, the first air supply passage 39 communicates with the space 41 formed between the manifold plate 34 and the rear shell 3 in the large hole 40 of the manifold plate 34, as clearly shown in FIG. A first inter-room connection passage 43 communicating with the transformation chamber 10, and a second inter-room connection passage 44 communicating with the first inter-room connection passage 43 and opening on a side surface of the manifold plate 34.
Are drilled respectively. Manifold plate 34
A semicircular filter 45 is fitted and provided at the semicircular concave fitting portion 38, that is, at the opening end of the first air supply passage 39.

Further, the first plate is provided on the manifold plate 34.
A normally open first solenoid on-off valve 46 is provided between the air supply passage 39 and the second air supply passage 42, and between the first room connection passage 43 and the second room connection passage 44. A normally closed second electromagnetic switching valve 47 is provided. These first and second solenoid on-off valves 46 and 47 can be constituted by any solenoid valve as long as the communication position and the cutoff position as shown in FIG. 4 are set. The first and second solenoid on-off valves 46 and 47 are both controlled to open and close by an ABS control controller (not shown).

Further, the second inter-chamber connection passage 44 is provided with an exhaust pipe 48.
Through the pressure chamber 9. Therefore, the constant pressure chamber 9 and the variable pressure chamber 10 can communicate with each other via the first and second connection passages 43 and 44 and the exhaust pipe 48 without passing through the control valve 23.

Thus, in the negative pressure booster system of the present embodiment, the concave fitting portion 35, the first and second air supply passages 39, 4 are provided.
2. Manifold plate 3 provided with first and second inter-chamber connection passages 43, 44, filter 45, first and second solenoid on-off valves 46, 47, and exhaust pipe 48, respectively.
The unit 4 is integrally assembled with the rear shell 3 of the negative pressure booster 1 with bolts 35 and nuts 36 to form a unit.

Further, the manifold plate 34 is formed with a cylindrical projection 34a projecting rearward, and the valve body 4 is provided between the cylindrical projection 34a and the input shaft 19.
A hermetic boot 49 made of an elastic material such as rubber is provided to completely cover the rear end portion and seal the inside. An annular third air supply passage 5 is provided between the inner peripheral surface of the boot 49 and the outer peripheral surface of the rear end of the valve body 4.
0 is formed.

The manifold plate 34 attached to the rear shell 3, by bolts 35, attached to the partition wall 51 for blocking between the engine room R ₁ and the cab R ₂ from the engine room R ₁ side. In a state in which the manifold plate 34 is attached to the partition wall 51, together with the cylindrical protrusion 34a through the hole 52 formed in the partition wall 51, so that the boot 49 is positioned within the cab R _2. The inner peripheral surface of the hole 52 of the partition wall 51 and the cylindrical projection 3
An annular air supply passage 53 is formed between the first air supply passage 39 and an outer peripheral surface of the first air supply passage 39.
8 and the filter 45 is to be positioned to face the annular air supply passage 53, the first supply passage 39 therefore comes to communicate with the inside of the cab R ₂ via the annular air supply passage 53.

In that case, the concave fitting portion 38 and the filter 45
Are located along the annular air supply passage 53. Thereby, the concave fitting portion 38 and the filter 45 and the annular air supply passage 5
The connection area between 3 can be set large can incorporate air in the cab R ₂ sufficiently. Moreover, even if the relative position between the concave fitting portion 38 and the filter 45 and the hole 52 is displaced to some extent, the concave fitting portion 38 and the filter 45 can be reliably connected to the annular air supply passage 53, and the assembling accuracy can be improved. It doesn't need to be that high.

Next, the operation of the negative pressure booster system of this embodiment will be described. When the vacuum booster 1 is in the inoperative position shown in the figure, the valve body 25 of the control valve 23 is connected to the first valve seat 26.
, And maintains a slight gap from the second valve seat 27, the atmosphere valve is in a closed state, and the vacuum valve is in an open state. Further, the first solenoid on-off valve 46 is set to be open as shown in FIG. 4 to communicate with the first and second air supply passages 39 and 42, and the second solenoid on-off valve 47 is set to be closed as shown in FIG. Thus, the first and second inter-room connection passages 43 and 44 are shut off. Therefore, the fifth hole 16 is provided in the third air supply passage 50,
The space 41, the second air supply passage 42, the open first solenoid on-off valve 46, the first air supply passage 39, the filter 45, and the third
Together through the supply passage 53 communicates with the inside of the cab R _2, the constant pressure chamber 9 and the variable pressure chamber 10 does not communicate via the first and second inter-chamber connection passages 43, 44.

When the brake pedal is depressed to perform normal braking in this state, the input shaft 19 is moved to the valve body 4.
Move forward towards. As the input shaft 19 advances, the valve plunger 18 moves forward with respect to the key member 21 and the valve body 4, and the valve body 25 of the control valve 23 moves to the second valve seat 27.
, The first valve seat 26 separates from the valve body 25, the vacuum valve closes, and the atmospheric valve opens. Thereby, the air at the atmospheric pressure in the cab R ₂ flows into the fifth hole 16, and further passes through the gap between the valve body 25 and the first valve seat 26, the third hole 14, and the passage 22. It flows into the transformation chamber 10.

The power piston 8 is actuated by the air flowing into the variable pressure chamber 10, and the valve body 4 moves forward. Therefore, the negative pressure booster 1 generates an output from the output shaft 28 to actuate the piston of the master cylinder. I do. Thereby, the normal brake operates. When the valve body 25 is seated on the first valve seat 26 and the atmosphere valve closes, air does not flow into the variable pressure chamber 10 and the advance of the valve body 4 stops. Thus,
The negative pressure booster 1 generates a boosted output at a predetermined servo ratio according to the input.

When the brake pedal is released to release the normal brake, the input shaft 19 is retracted, and the valve plunger 18 is retracted relatively to the valve body 4 until the key member 21 contacts the rear surface of the hole 20. When the valve plunger 18 is retracted, the valve body 25 is separated from the second valve seat 27 and the vacuum valve is opened, and the air introduced into the variable pressure chamber 10 passes through the passage 22, the valve body 25 and the second valve seat 27. Gap, passage 1
7, flows out to the negative pressure source through the constant pressure chamber 9 and the negative pressure introducing pipe 33, and the pressure in the variable pressure chamber 10 decreases. This allows
Due to the elastic force of the return spring 31, both the valve body 4 and the power piston 8 are retracted, and the inoperative state shown in FIG. 1 is established.

If at least one of the wheels has a tendency to lock during braking by the operation of the negative pressure booster 1, a controller (not shown) detects this tendency to lock as in the case of conventional general ABS control. When the controller detects the tendency to lock the wheels, the first and second solenoid on-off valves 46 and 47 are activated.
Are turned on, so that the first solenoid on-off valve 46 closes and the second solenoid on-off valve 47 opens. Therefore, the fifth
The hole 16 blocks from the cab R _{2 and the}
0 communicates with the constant-pressure chamber 9 via the first inter-room connection passage 43, the opened second electromagnetic on-off valve 47, and the second inter-room connection passage 44. As a result, the air in the variable pressure chamber 10 is
, The pressure difference between the variable pressure chamber 10 and the constant pressure chamber 9 is reduced, the output of the negative pressure booster 1 is reduced, and the brake pressure is reduced. At this time, the output of the negative pressure booster 1 decreases, the valve body 4 retreats, and the valve band 25 moves to the first position.
The user releases the toilet seat 26 and opens the air valve. However, the fifth hole 1
Because 6 is cut off from the cab R within _2, air in the cab even atmospheric valve opens is not able to flow into the variable pressure chamber 10, the negative pressure booster output of the device 1 is not increased.

In this state, when the tendency to lock the wheels is released and the wheel speeds recover to the predetermined speed, the controller sets the first speed.
Then, both the second electromagnetic on-off valves 46 and 47 are turned off, and the first electromagnetic on-off valve 46 is opened and the second electromagnetic on-off valve 47 is closed. Therefore, the fifth hole 16 again communicates with the inside of the cab R _2, the variable pressure chamber 10 via the first and second inter-chamber connection passages 43, 44 to cut off from the constant pressure chamber 9. Thus, the outflow of the pressure chamber 9 of the air in the variable pressure chamber 10 is stopped, since the air in the cab R ₂ is flows into the variable pressure chamber 10 again, the negative pressure booster 1 Output Increases, and the brake pressure is increased.

In this manner, the controller repeatedly controls the turning on and off of the first and second solenoid valves 46 and 47 until the tendency to lock the wheels is completely eliminated, thereby reducing the brake pressure and increasing the pressure. The control is performed repeatedly.

According to the negative pressure booster system of this embodiment, the air supply passage, the inter-room connection passage, the first and second solenoid on-off valves 4
6,47, and to form a unit assembled in an exhaust pipe 48 negative pressure booster manifold plate 34 incorporating integrally 1, unit the unit to the vehicle body of the partition wall 51 is located in the engine room R ₁ Since the unit is mounted and the air at atmospheric pressure is taken in from the cab, after the unit is mounted on the vehicle body, only the electrical connection work to the first and second solenoid on-off valves 46 and 47 need be performed. Therefore, the mounting work of the negative pressure booster 1 and the respective solenoid on-off valves 46 and 47 becomes extremely easy.

The first and second solenoid on-off valves 46, 47
Are located in the engine room R ₁ , so that the operating sounds of the solenoid valves 46 and 47 become quiet in the cab R ₂ .

In addition, the first and second solenoid on-off valves 46,
Be located together in the engine room R ₁ to 47, since the air atmospheric pressure to be introduced into the negative pressure booster 1 is set to air in the cab, introduce clean air different from the air in the engine room R ₁ Will be able to

In the above-described example, the case where the negative pressure booster 1 and the electromagnetic on-off valve are provided in the ABS has been described. However, the present invention is not limited to this. A solenoid valve that holds the operating state and releases the brake operating state when the vehicle starts, a solenoid valve that is used for automatic braking that automatically applies the brake when the predetermined brake operating condition is reached, or when the driving wheels tend to idle The present invention can be applied to any brake system provided with an electromagnetic valve for controlling the operation of a brake such as an electromagnetic valve for a traction control system for applying a brake to a drive wheel.

[0042]

As is apparent from the above description, according to the negative pressure boosting system of the present invention, the manifold in which the air supply passage, the inter-room connection passage, the first and second solenoid valves are integrally incorporated. Since the plate is assembled to the vacuum booster to form a unit, this unit is mounted on the vehicle body so that the unit is located in the engine room, and furthermore, air at atmospheric pressure is taken in from the cab, After the unit is mounted on the vehicle body, the operation can be completed only by performing only the electrical connection work to the first and second solenoid valves. Therefore, not only is the work of mounting the negative pressure booster and the respective solenoid valves extremely easy, but also the work can be easily performed even if the working space is small.

Further, since the first and second solenoid valves are both located in the engine room, the operation sound of each solenoid valve becomes quiet in the cab. Moreover, even if both the first and second solenoid valves are arranged in the engine room, the air at atmospheric pressure introduced into the negative pressure booster is the air in the cab, so that clean air can be introduced.

In particular, according to the third aspect of the present invention, since the open end of the air supply passage extends along the annular air supply passage, the connection area between the open end and the annular air supply passage can be set large.
Thereby, it becomes possible to sufficiently take in the air in the cab. Moreover, even if the relative position between the opening end and the hole of the partition wall is displaced to some extent, the opening end can be reliably connected to the annular air supply passage, and it is not necessary to increase the assembling accuracy so much. Work becomes easier.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view partially showing an example of an embodiment of a negative pressure booster system according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a diagram schematically showing a negative pressure booster and an electromagnetic on-off valve of the example shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Negative pressure booster, 2 ... Front shell, 3 ... Rear shell, 4 ... Valve body, 8 ... Power piston, 9 ... Constant pressure chamber, 10 ... Variable pressure chamber, 16 ... Control valve, 17 ... Passage, 18 ...
Valve plunger, 19 input shaft, 23 control valve, 25 valve element, 26 first valve seat, 27 second valve seat, 28 output shaft,
33: negative pressure introducing pipe, 34: manifold plate, 34
a ... cylindrical protrusion, 35 ... bolt, 36 ... nut, 37 ...
Seal member, 38: concave fitting portion, 39: first air supply passage, 41
... space, 42 ... second air supply passage, 43 ... first room connection passage, 44 ... second room connection passage, 45 ... filter, 46 ...
First electromagnetic on / off valve, 47: second electromagnetic on / off valve, 48: exhaust pipe, 49: boot, 50: third air supply passage, 51: partition wall,
52: hole, 53: annular air supply passage

Claims (4)

[Claims] 1. A front shell and a rear shell forming an internal space, the internal space being partitioned into a constant pressure chamber which is always connected to a negative pressure source and a variable pressure chamber into which air at atmospheric pressure is introduced during operation. A power piston that operates by a pressure difference between the pressure chamber and the constant pressure chamber to generate an output, an air valve that controls the introduction of atmospheric pressure air to the variable pressure chamber, and communication between the variable pressure chamber and the constant pressure chamber; A negative pressure booster including at least an input shaft configured to control the operation of the control valve, the control valve including a vacuum valve to be controlled, and a control valve that moves forward by operating the brake operating member and retracts by releasing the operation of the brake operating member. An air supply passage attached to the rear shell and introducing the atmospheric pressure air to the atmospheric valve; a normally open first solenoid valve provided in the air supply passage to control opening and closing of the air supply passage;
A normally-closed second solenoid valve provided in the inter-room connection passage for communicating between the constant-pressure chamber and the variable-pressure chamber without interposing the control valve, and provided in the inter-room connection passage for controlling opening and closing of the inter-room connection passage; A manifold plate, wherein the negative pressure booster and the manifold plate are integrally assembled to form a unit, and the unit is provided on a partition wall that blocks between an engine room and a cab, A negative pressure boosting system, wherein an open end of an air supply passage is attached from the engine room side so as to face the cab. 2. A hole is formed in the partition so as to penetrate between the surface on the engine room side and the surface on the driver's cab side. The air supply passage extends through the hole into the cab so as to form an air passage, and an opening end of the air supply passage faces the annular air supply passage. Negative pressure booster system as described. 3. The negative pressure boosting system according to claim 2, wherein an open end of the air supply passage is formed in an arc shape along the annular air supply passage. 4. The vacuum booster system according to claim 1, wherein a filter is provided at an open end of the air supply passage.