JP2000296767A - Vehicle brake booster device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To variably control a booster by arranging selector valves in atmosphere and negative pressure introduction port of a brake booster and driving the valves. SOLUTION: A negative pressure chamber 8 of a booster part comprising the negative pressure chamber 3 and a transformer chamber 4 across a diaphragm 2 is provided with a first introduction port 11 for a negative pressure passage connected to an engine negative pressure and constitutes a servo mechanism of the negative pressure, the atmosphere, and the brake pedal tread force and a second introduction port 12 for the atmosphere passage. A first selector means 15 changing over the introduction between the negative pressure and the atmosphere to the first introduction port 11 and changing over between the introduction and interruption of the atmosphere to the second introduction port 12 by a drive signal of a mounted controller is also arranged therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake booster for a vehicle, and more particularly to a booster device having a switching means capable of switching, shutting off, and communicating with a negative pressure and the atmosphere, and a control method therefor. .

[0002]

2. Description of the Related Art Conventionally, a brake booster device for a vehicle is connected to a brake pedal, generates brake fluid pressure in accordance with the depression force of the brake pedal, and guides it to a wheel cylinder disposed on each wheel to apply a brake. It is.
Since a braking force several times the driver's pedaling force is generated,
A large braking force can be obtained with a relatively light braking force. However, a driver having weak leg strength, such as a woman or an elderly person, may not be able to effectively use a brake system mounted on a vehicle, for example, an anti-skid brake system. That is, there are cases where the pedaling force is weak, the braking force does not increase by a predetermined amount or more, and the function of the vehicle does not operate.

[0003] Further, as an apparatus described in Japanese Patent Application Laid-Open No. Hei 2-20461, an apparatus capable of arbitrarily controlling the boosting of a booster has been proposed. FIG. 8 is a schematic diagram of this conventional device, and the function of this device will be described. An operating rod 1 receives a force from a brake pedal, and a master cylinder 18 has a booster disposed between them. The booster section is divided by a diaphragm 2, one of which is composed of a negative pressure chamber 3 and the other of which is composed of a variable pressure chamber 4. In a normal operation, when the driver depresses the brake pedal, the atmosphere is introduced into the variable pressure chamber 4, a pressure difference from the negative pressure chamber 3 is generated, and the diaphragm 2 is moved to the left in the figure, so that the master cylinder 18 is moved. Pressing pressure occurs. Here, an inlet 13 is provided in the variable pressure chamber 3, another inlet 14 is provided in the negative pressure chamber 14, and two-way valves 40 a and 40 b are provided in the inlet 13, and two-way valves are provided in the inlet 14. 41a, 41
b are provided respectively. The valve 40a can switch between introducing and shutting off the atmosphere, and the valve 40b can switch between shutting off and introducing the negative pressure. Similarly, the valve 41a can switch between introducing or shutting off the negative pressure, and the valve 41b can switch between shutting off or introducing the atmosphere. This switching operation is performed by a drive signal from a control device (not shown).

[0004] By driving the valves 40a, 40b,
Alternatively, by driving the valves 41a and 41b, the negative pressure and the capacity of the atmosphere can be varied, and the movement of the diaphragm 2 can be controlled. This operation increases the assist force of the driver's treading force by increasing the atmosphere or the negative pressure.
Conversely, this assist force is reduced by reducing the atmosphere or the negative pressure. By these valve drives, for example, when the brake fluid pressure is insufficient, the assist force can be increased, and when the brake fluid pressure is more than unnecessary, the assist force can be decreased.
Here, the increase / decrease of the assist force is the same as the boost control for increasing / decreasing the boost.

[0005]

In various driving situations, it is often better to generate a variable brake fluid pressure with respect to the brake depression force. For example, when the brake assist force is changed, a brake force that is many times the driver's depressing force may be required for excessive speed. Conversely, during anti-skid brake control on snowy roads, the brake pedal force is often much higher than the control brake force. In this case, the assist force decreases, and furthermore, the negative assist, that is, the unnecessary driver's brake force is reduced. It is better to reduce. Further, depending on the driving situation, there is a driving situation that requires a pedal return operation for preventing the brake pedal from entering and a control that extends to automatic braking. SUMMARY OF THE INVENTION It is a first object of the present invention to provide a booster device that generates an appropriate braking force according to a running situation.

In the conventional device shown in FIG. 8, it is possible to increase or decrease the assist force. However, in an actual booster device, there is a servo mechanism based on the driver's pedaling force, negative pressure, and equilibrium with the atmosphere. Control using only the valve mechanism as shown in FIG. 8 has a problem in fail-safe. For example, when the valve mechanism fails, the control by the normal driver's pedaling power cannot be performed. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a booster device capable of generating an arbitrary braking force while ensuring fail-safe by using a conventional servo mechanism. This is the purpose of 2.

[0007]

In a vehicle brake booster device according to the present invention, a brake force corresponding to an operation force of a driver is generated in conjunction with an operation of a brake pedal of the vehicle. The variable pressure chamber of the booster section composed of a negative pressure chamber and a variable pressure chamber is connected to the negative pressure passage in a brake booster device having a negative pressure passage and an atmospheric passage to constitute a servo mechanism of a negative pressure, the atmosphere and a brake pedal depression force. And a second inlet connected to the air passage, and switching between introduction of the negative pressure and the air to the first inlet by a drive signal of a mounted control device. And a first switching means capable of switching between introducing and shutting off the air into the second inlet.

Further, in the vehicle brake booster device according to the present invention, the operation is performed in conjunction with the operation of the brake pedal of the vehicle.
It generates a braking force corresponding to the driver's operation force.The transformer chamber of the booster section consisting of a negative pressure chamber and a variable pressure chamber sandwiching the diaphragm constitutes a servo mechanism of negative pressure, atmosphere and brake pedal depression force. Therefore, in a brake booster device having a negative pressure passage and an atmosphere passage, a first introduction port connected to the negative pressure passage, a second introduction port connected to the atmosphere passage, and a third introduction port communicating with the variable pressure chamber. Switching between the introduction of the negative pressure to the first inlet and the introduction of the atmosphere by the drive signal of the mounted control device, and the switching of the introduction or the interruption of the atmosphere to the second introduction port. And a second switching means capable of shutting off or switching the introduction of the negative pressure to the third inlet.

Further, in the vehicle brake booster device according to the present invention, the brake booster device operates in conjunction with the operation of the brake pedal of the vehicle.
It generates a braking force corresponding to the driver's operation force.The transformer chamber of the booster section consisting of a negative pressure chamber and a variable pressure chamber sandwiching the diaphragm constitutes a servo mechanism of negative pressure, atmosphere and brake pedal depression force. Therefore, in a brake booster device having a negative pressure passage and an atmosphere passage, a first introduction port connected to the negative pressure passage, a second introduction port connected to the atmosphere passage, and a third introduction communicating with the variable pressure chamber. An inlet and a fourth inlet communicating with the negative pressure chamber, and switching between the introduction of the negative pressure to the first inlet and the atmosphere is possible by a drive signal of a mounted control device; and A first switching means capable of switching between introducing and shutting off the atmosphere to the second inlet is provided, and a second switching means capable of switching between shutting off and introducing the negative pressure to the third inlet is provided.
Switching means is provided, and third switching means capable of switching between the introduction of the negative pressure to the fourth inlet and the atmosphere is provided.

Further, in the method for controlling the brake booster device for a vehicle according to the present invention, the first switching means switches from a negative pressure to the atmosphere into the first inlet and from the atmosphere to the second inlet. One step, and conversely, a second step of switching from the atmosphere to the first inlet to a negative pressure, and a second step of switching to the atmosphere to the second inlet, and a third step of switching to the negative pressure by the second switching means. Conversely, a fourth step of switching to negative pressure cut-off, a fifth step of switching from negative pressure to introduction of atmospheric pressure in the third switching means, and a sixth step of switching to introduction of negative pressure from atmosphere to the contrary, And a control selecting step of selecting the first to sixth steps according to

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a booster device equivalent to a conventional one, and the booster mechanism will be briefly described. In FIG. 1, reference numeral 1 denotes an operating rod which is moved by a brake pedal (not shown) operated by a driver. Reference numeral 2 denotes a diaphragm, which includes a negative pressure chamber 3 and a transformation chamber 4.
Is divided into two. Reference numeral 5 denotes a plunger, which moves to the left in the figure by the driver's treading force, and further operates so that the push rod 6 is pushed to the left to transmit a force to a master cylinder (not shown). Next, the servo mechanism will be described. When the brake is not depressed, the negative pressure valve mechanism 8 from the negative pressure passage 7 is opened and the atmospheric valve mechanism 9 is closed. Therefore, the plunger 5 and the operating rod 1 have moved to the right in the figure. When the brake pedal is slightly depressed, both the negative pressure valve mechanism 8 and the atmospheric valve mechanism 9 are closed. When the brake pedal is further depressed, the negative pressure valve function 8 is closed and the atmospheric valve mechanism 9 is opened. Here, the atmosphere is introduced into the variable pressure chamber 4, and the pressure difference acting on the diaphragm 2 applies a force to the push rod 6. The brake pedal depressing force is transmitted in the same way via the reaction disk 10, and a predetermined boost is generated with respect to the brake pedal depressing force. On the other hand, when a predetermined boost or more is generated, the atmosphere valve mechanism 9 is closed, and the negative pressure valve mechanism 8 is closed.
Is opened, the air in the transformer chamber is exhausted, and the servo mechanism operates so that a braking force corresponding to the pedaling force is generated.

The present invention will be described using the booster configured as described above. FIG. 2 is a schematic diagram of a booster device according to Embodiment 1 of the present invention. The negative pressure chamber 3 and the variable pressure chamber 4 are divided by the diaphragm 2, and the negative pressure passage 7, the negative pressure valve 8, and the atmospheric valve 9 constituting the servo mechanism in FIG. There is a second inlet 12 for the valve passage. The fourth inlet 14 communicating with the negative pressure chamber 3 is connected to the engine negative pressure. The first inlet 11 is provided with a switching between the introduction of the negative pressure and the atmosphere, and the second inlet 12 is provided with a first switching valve 15 capable of introducing or shutting off the atmosphere. Next, the operation of the first switching valve 15 will be described. This switching valve can change the boost of the booster, and is a control valve for performing boost control. It is also a valve that can deactivate the servo mechanism. Normally, the booster mechanically switches between the negative pressure and the atmosphere in accordance with the depression force of the brake pedal, so that a predetermined boost can be generated. Here, by switching between the negative pressure and the atmosphere arbitrarily according to the drive signal of the mounted control device, the air introduction amount is varied and the boosting operation is changed. In particular, with the first switching valve 15, it is possible to increase the boost. By introducing the atmosphere into the first inlet 11, the capacity of the atmosphere entering the transformer chamber is increased, and the boost is increased. On the other hand, when the first switching valve 15 is returned to the original state, a normal booster function can be generated by returning to the normal booster function.

FIG. 3 shows the relationship between the brake depression force and the brake pressure. A normal booster device has characteristics as shown by a solid line 20. When the brake pedal is slightly depressed, the atmosphere is introduced into the variable pressure chamber 4, and a brake pressure several times the depressing force is generated. If the pedal is further depressed, the brake pressure acts to gradually increase in accordance with the depressing force. However, by controlling the switching valve 15 of the present invention, it is possible to increase the brake boosting as shown by the broken line 21 by increasing the introduction of the atmosphere. For example, by introducing the atmosphere from the point A in the drawing, the brake pressure due to the pedaling force is changed to A
It is possible to return to point A by moving to one point or conversely introducing a negative pressure. Depending on the driving situation,
By increasing the brake boost, the brake pressure can be controlled to a more appropriate high pressure. This has the effect that even a driver with weak leg strength can make maximum use of the braking capacity of the vehicle. In addition, it is easily possible to separate the first switching valve 15 for the negative pressure introduction port 11 and the atmosphere introduction port 12 and to separately provide the switching valve.

Embodiment 2 FIG. Next, a second embodiment will be described. The brake pressure is generated even when the driver does not step on the brake pedal, and has a so-called automatic braking function. Drives the first switching valve 15 (ON)
Then, when the atmosphere is introduced from the negative pressure, the servo mechanism is killed and the atmosphere is forcibly introduced into the variable pressure chamber 4, and a brake pressure is generated. To release the automatic brake after the automatic brake is generated, the first switching valve 15 is deactivated (OF).
F) If the brake is not applied, the brake pressure is rapidly reduced. Here, the first switching valve 15 is turned ON / O.
By performing the FF control, not only can the brake pressure be increased and decreased, but also the gain can be varied by the ON / OFF ratio. Since the brake can be automatically applied in this manner, the application is wide-ranging, and can be used for applications such as holding the brake while the vehicle is stopped, and automatically decelerating the vehicle while traveling.

Embodiment 3 Next, a third embodiment will be described with reference to FIG. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts. A third introduction port 13 communicating with the transformation chamber 4 is added, and a second switching valve 16 that can shut off or introduce a negative pressure is provided. By using the second switching valve 16 as well, the boost can be reduced. The first switching valve 15 is deactivated (negative pressure and air introduction state) by the on-board control device, and the second switching valve 16 is driven to introduce negative pressure. As a result, a negative pressure enters the transformation chamber 4, and the negative pressure chamber 3 is connected to the engine negative pressure, so that the diaphragm 2 moves to the right in the drawing. Due to this movement, a brake pressure corresponding to the conventional brake depression force cannot be generated, and a brake pressure with reduced boost is generated.

Looking at the reduction in boosting with the brake characteristics in FIG.
This means that the normal brake pressure generation characteristic 20 can be changed to a broken line 22. That is, for example, the brake pressure at point A can be moved to A2 by reducing the boost. In particular, during anti-skid brake control on snowy roads, etc., the driver strongly presses the brakes to stop the vehicle quickly. On the other hand, the control brake pressure is often operated at a pressure lower than this pressure. In this case, unnecessary brake pressure is generated in the brake booster. The useless brake pressure can be reduced by the boost reduction control.

Embodiment 4 Next, a fourth embodiment will be described with reference to FIG. In the figure, the same reference numerals as those in FIG. 2 or 4 indicate the same or corresponding parts. A third switching valve 17 that can introduce or shut off a negative pressure or the atmosphere is provided at a fourth introduction port 14 communicating with the negative pressure chamber 3. This third switching valve 17 is used for the function of pushing back the brake pedal.
The negative pressure chamber 3 is normally connected to an engine negative pressure, and the variable pressure chamber 4 can generate a brake pressure by introducing air. Here, by driving the third switching valve 17, the negative pressure in the negative pressure chamber is switched to the atmosphere. Further, by driving the second switching valve 16, a negative pressure is introduced into the variable pressure chamber. Then, there is no pressure difference between the left and right rooms, and furthermore, the relationship of negative pressure chamber pressure> transformation chamber pressure is established, so that the diaphragm 2 moves to the right in the figure and the brake pedal can be pushed back. By returning the brake pedal, control that could not be performed until now becomes possible. For example, even if a large amount of brake pressure is used in an anti-skid brake or the like, the brake pedal does not bottom out, so that there is a margin for control. The driver can be alerted by pushing the brake pedal back. If no brake pressure is required, the brake pressure can be reduced to zero.

Embodiment 5 Next, a fifth embodiment will be described from a control aspect. As shown in FIG. 5, a control device 30 mounted on the vehicle is provided in addition to the booster device. The control device 30 outputs signals for driving the switching valves 15, 16, 17 based on information from various sensors. For example, by inputting the wheel speed sensors 31a to 31d, the rotation speed information of the wheels can be detected,
Pulling can also execute anti-skid brake control. Further, the speed and strength of the driver's depression of the brake are detected based on position information of the brake pedal by another sensor 32 such as a brake pedal sensor. In addition, distance data from a preceding object can be input by an inter-vehicle distance sensor.

The control device 30 outputs a drive signal to perform boost control, automatic braking, and brake pedal return control based on the sensor information. An example of boost control will be described with reference to FIG. It is assumed that the brake pressure changes with time as shown in FIG. 34 is a typical brake pressure waveform of the anti-skid brake control. This is controlled so that the wheels are in a predetermined slip range by increasing or decreasing the brake pressure in accordance with changes in the wheel speed sensors 31a to 31d. With this control, an anti-skid control device is provided that can appropriately increase or decrease the braking pressure in accordance with the wheel speed and stably stop the vehicle. In this case, the normal driver often keeps depressing the brake pedal as indicated by a broken line 33. However, the actual brake pressure is as shown in a waveform 34, and this pressure difference is not only useless, but this pressure difference often fluctuates due to the driver's brake depressing force. It appears as a change. Therefore, boost control is executed.
When the first switching valve or the second switching valve is driven and it is confirmed that the anti-skid brake control has been started (t1), the assist force is maintained. When the brake pressure starts to increase (t
2 to t3), the assist force is gradually increased. When the brake pressure is reduced (t3 to t4), the assist force is reduced. Thus, the brake pressure can be controlled as shown by a waveform 35. As described above, the assist force can be increased or decreased by increasing or decreasing the capacity of the atmosphere in the variable pressure chamber or increasing or decreasing the negative pressure capacity of the negative pressure chamber according to the traveling state. In addition, it is possible to control the brake pressure to be kept substantially constant irrespective of the change in the brake pedal force by the driver.

In addition to the anti-skid brake control,
It can also be used for idling control of drive wheels, that is, traction control. The fact that the drive wheels have slipped is determined by the wheel speed sensor 31.
The automatic braking can be applied by driving the first switching valve 15 and the second switching valve 16. This action can be applied not only to traction control but also to an automatic deceleration function of an excessive vehicle speed when there is an obstacle ahead or when entering a curve. FIG. 7 is a table summarizing the control modes and the driving states of the switching valves using the first to third switching valves. Here, OFF indicates a non-driving state, and each of the switching valves 15 and in FIGS.
16 and 17 show that the valve state is on the left side. The first switching valve 15 is OFF and is in the introduced state, and the second switching valve 1
Numeral 6 indicates a shut-off state when OFF, and a third switching valve 17 indicates a negative pressure shut-off state when OFF. On the other hand, ON is a driving state, the first switching valve 15 is in the shut-off state, the second switching valve 16 is in the introduction state,
The switching valve is in the air introduction state. ON / OFF indicates a controlled state.

The reduction b of the boost control in this table will be described. The normal boost reduction control uses the reduction a described in the third embodiment. However, in the booster device also having the third switching valve 17, the boost reduction b mode can be used. This is a method in which the negative pressure chamber 3 is used without using the variable pressure chamber 4, and the boost can be rapidly reduced by introducing the atmosphere into the negative pressure chamber. By using these modes arbitrarily according to the running state of the vehicle, all types of brake booster control can be performed, and any brake pressure can be generated. Further, the control device can be included in the mounted anti-skid brake control device or the like, for example. By integrating with the control device for controlling the brake, there is an effect that space saving and cost reduction can be achieved. . Furthermore, each switching valve can be built in the booster device, and by integrating it, space can be saved.

[0022]

The vehicle brake booster device of the present invention is constructed as described above, and has the following effects.

According to the brake booster device of the present invention, a drive signal for a control device having a first inlet connected to the negative pressure passage and a second inlet connected to the atmosphere passage is provided. Accordingly, the first switching means capable of switching between the introduction of the negative pressure to the first inlet and the atmosphere and the introduction or shutting off of the air to the second inlet is provided. So the booster boost can be changed in the increasing direction,
There is also an effect that the brake can be automatically applied.

Further, according to the brake booster device of the present invention, the first inlet connected to the negative pressure passage, the second inlet connected to the atmosphere passage, and the third inlet communicating with the variable pressure chamber.
An inlet, and a switch between the negative pressure to the first inlet and the air can be switched by a drive signal of a mounted control device; and the introduction or shutoff of the air to the second inlet. Is provided, and the second switching means capable of shutting off or switching the negative pressure to the third inlet is provided, so that the booster of the booster is increased. And reduction can be performed in both directions, and the brake can be automatically applied.

Further, according to the brake booster device of the present invention, the first inlet connected to the negative pressure passage, the second inlet connected to the atmosphere passage, and the third inlet communicating with the variable pressure chamber.
It has an inlet and a fourth inlet communicating with the negative pressure chamber, and can switch between the introduction of the negative pressure to the first inlet and the atmosphere by a drive signal of a mounted control device, and A first switching means capable of switching between introducing and shutting off the atmosphere into the second inlet is provided, and a second switching means capable of switching between shutting off and introducing the negative pressure to the third inlet is provided. And the third switching means capable of switching between the introduction of the negative pressure to the fourth inlet and the introduction of the atmosphere is provided, so that the booster boost control, the automatic brake operation control, and the brake pedal are controlled. There is an effect that the return control can be performed.

According to the control method of the brake booster device according to the present invention, the first switching means switches from the negative pressure to the atmosphere introduction into the first introduction port to the atmosphere interruption to the second introduction port. Conversely, a second step of switching from the atmosphere to the first inlet to the negative pressure and switching to the second inlet to the atmosphere, a third step of switching to the negative pressure by the second switching means, and vice versa. The fourth step of switching to negative pressure cutoff, the fifth step of switching from negative pressure to introduction of atmospheric pressure by the third switching means, and the sixth step of switching from atmospheric pressure to introduction of negative pressure by the third switching means. And a control selecting step of selecting the first to sixth steps accordingly. Therefore, there is an effect that the switching valve control can be performed in accordance with the running state of the vehicle, and thus any brake pressure generation control can be performed.

[Brief description of the drawings]

FIG. 1 is a structural view showing a conventional brake booster device.

FIG. 2 is a schematic diagram showing a brake booster device according to Embodiment 1 of the present invention.

FIG. 3 is a characteristic diagram of the brake booster device according to the first embodiment.

FIG. 4 is a schematic diagram showing a brake booster device according to a second embodiment.

FIG. 5 is a schematic diagram illustrating a brake booster device according to a third embodiment and a block diagram of a control device.

FIG. 6 is a brake pressure waveform diagram according to a third embodiment.

FIG. 7 is a table of drive and control modes of a switching valve according to a third embodiment.

FIG. 8 is a schematic diagram of a conventional brake booster device.

[Explanation of symbols]

1 operating rod, 2 diaphragm, 3
Negative pressure chamber, 4 variable pressure chambers, 11 first inlet, 12 second inlet, 13 third inlet, 14 fourth inlet, 15 first switching valve, 16 second switching valve, 17 third switching valve, 18
Master cylinder.

Claims (4)

[Claims] 1. In conjunction with operation of a brake pedal of a vehicle,
It generates a braking force corresponding to the driver's operation force.The transformer chamber of the booster section consisting of a negative pressure chamber and a variable pressure chamber sandwiching the diaphragm constitutes a servo mechanism of negative pressure, atmosphere and brake pedal depression force. Therefore, in a brake booster device having a negative pressure passage and an atmospheric passage, the brake booster device includes a first inlet connected to the negative pressure passage, and a second inlet connected to the atmospheric passage. A first switching means is provided which is capable of switching between the introduction of the negative pressure to the first inlet and the atmosphere by the drive signal and of switching the introduction or the cutoff of the atmosphere to the second inlet. A brake booster device for a vehicle. 2. In conjunction with operation of a brake pedal of the vehicle,
It generates a braking force corresponding to the driver's operation force.The transformer chamber of the booster section consisting of a negative pressure chamber and a variable pressure chamber sandwiching the diaphragm constitutes a servo mechanism of negative pressure, atmosphere and brake pedal depression force. Therefore, in a brake booster device having a negative pressure passage and an atmosphere passage, a first introduction port connected to the negative pressure passage, a second introduction port connected to the atmosphere passage, and a third introduction port communicating with the variable pressure chamber. It is possible to switch between introduction of the negative pressure to the first inlet and the atmosphere by a drive signal of a mounted control device,
Further, a first switching means capable of switching between introducing and shutting off the atmosphere into the second inlet is provided, and a second switching means capable of switching between shutting off and introducing the negative pressure to the third inlet is provided. A brake booster device for a vehicle, which is provided. 3. Interlocking with operation of a brake pedal of the vehicle,
It generates a braking force corresponding to the driver's operation force.The transformer chamber of the booster section consisting of a negative pressure chamber and a variable pressure chamber sandwiching the diaphragm constitutes a servo mechanism of negative pressure, atmosphere and brake pedal depression force. Therefore, in a brake booster device having a negative pressure passage and an atmospheric passage, a third inlet connected to the negative pressure passage, a second inlet connected to the atmospheric passage, and a third communicating with the variable pressure chamber.
An inlet, and a fourth inlet communicating with the negative pressure chamber,
The drive signal of the mounted control device allows switching between the introduction of the negative pressure to the first inlet and the introduction of the atmosphere and the second inlet.
A first switching means capable of switching between introducing and shutting off the atmosphere to the inlet; and a second switching means capable of switching between shutting off and introducing the negative pressure to the third inlet; A brake booster device for a vehicle, further comprising a third switching unit capable of switching between introduction of the negative pressure to the fourth inlet and the atmosphere. 4. A first switching means, wherein a first step is a step of switching from a negative pressure to the atmosphere to the first inlet, and a step of switching to the shutoff of the atmosphere to the second inlet. Pressure introduction,
A second step for switching to atmospheric introduction at the second inlet;
A third step of switching to negative pressure introduction by the switching means, a fourth step of switching to negative pressure cut-off, a fifth step of switching from negative pressure to atmospheric introduction by the third switching means, and a negative A control method for a vehicle brake booster device, comprising: a sixth step of switching to pressure introduction; and a control selecting step of selecting the first to sixth steps according to a running state of the vehicle.