JPH1035471A - Brake booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake booster by which control such as anti-skid control can be carried out by means of simple constitution. SOLUTION: In a brake booster 1, a pressure varying chamber 8 and a negative pressure chamber 9 are arranged, while a first mechanical valve 11, a second mechanical valve 12, a first control valve 13, and a second control valve 14 are arranged for regulating pressures in both of the chambers 8, 9. The first control valve 13, which is arranged in a second communication path 21 extending from a branch point B1 to the pressure varying chamber 8, is a solenoid valve which is driven toward two positions for connection (off) and disconnection (on) on the basis of a signal from an ECU when anti-skid control or hill-hold control is carried out. On the other hand, the second control valve 14, which is arranged in a third communication path 23 connecting the pressure varying chamber 8 and the negative pressure chamber 9 together, is a solenoid valve driven toward two positions for connection (on) and disconnection (off) on the basis of a signal from the ECU when anti-skid control is carried out.

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 increasing braking force and improving braking performance.

[0002]

2. Description of the Related Art Conventionally, a so-called brake booster for increasing the depressing force of a brake pedal has been attached to a vehicle in order to reliably perform a brake operation by a driver.
This brake booster increases the depressing force of a brake pedal and applies a large force to the master cylinder by utilizing, for example, a difference between a negative pressure on the intake side of the engine and the atmospheric pressure.

In recent years, a technique for performing anti-skid control using this brake booster has been proposed (see Japanese Patent Application Laid-Open No. Hei 2-20461). This technology adjusts the pressure in the negative pressure chamber and the variable pressure chamber by switching the connection destination of the negative pressure chamber and the variable pressure chamber of the brake booster to the negative pressure source and the atmosphere according to the slip state of the wheels, thereby This is a technique for controlling the pressure of the master cylinder to optimize the slip state of the wheels to improve the braking force.

[0004]

However, in this technique, at least four solenoid valves are required to switch the connection destination of the negative pressure chamber or the variable pressure chamber to the negative pressure source or the atmosphere.
There has been a problem that the structure of the solenoid valve, the pipe and the like becomes complicated.

Further, in the above-mentioned technique, four electromagnetic valves are required even if only the anti-skid control is performed at the time of braking, so that, for example, traction control at the time of acceleration, etc.
In order to perform other control other than the above, there is a problem that a more complicated configuration must be added.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a brake booster capable of performing control such as anti-skid control with a simple configuration.

[0007]

In the brake booster according to the present invention, as shown in FIG. 1A, in addition to the first and second mechanical valves, (from the first communication passage to the transformer chamber). The first control valve is provided in the second communication passage, and the second control valve is provided in the third communication passage (communicating between the variable pressure chamber and the negative pressure chamber).

A negative pressure is introduced into the negative pressure chamber from, for example, a negative pressure source such as an intake side of an engine, and a variable pressure chamber is supplied with a pressure higher than the negative pressure from a pressure source such as atmospheric pressure. Is introduced. Also, when the driver depresses the brake pedal, the first mechanical valve is mechanically switched from the communicating state to the shut-off state by a member that moves in conjunction with the depressing operation, and is switched from the variable pressure chamber and the pressure source to the negative pressure chamber. To prevent the pressure in the negative pressure chamber from increasing. On the other hand, when the brake pedal is depressed, the second mechanical valve mechanically switches from the shut-off state to the communicating state, and atmospheric pressure or the like is introduced into the variable pressure chamber via the first and second communication passages. FIG. 3 shows a state where the brake pedal is not depressed.

Therefore, in the brake booster provided with the first and second mechanical valves, when the driver performs the brake operation, the operation of the two mechanical valves causes the pressure difference between the variable pressure chamber and the negative pressure chamber. Is generated, and the boosting action of the brake booster is exerted by this pressure difference. In particular, in the present invention, the second communication path is provided with a first control valve for controlling the opening and closing of the second communication path, and the third communication path connecting the negative pressure chamber side and the variable pressure chamber side is provided with a third control valve. A second control valve for controlling the opening and closing of the communication passage is provided.

Therefore, by controlling the open / close state of the first and second control valves in accordance with a command signal at the time of vehicle control, the pressure in the negative pressure chamber and the variable pressure chamber is adjusted, and the pressure difference between the two chambers is adjusted. The onset or dissolution can be controlled, thereby controlling the onset or deactivation of the boosting action. Therefore, by controlling the boosting action, anti-skid control and hillhold control can be suitably performed as described later in detail.

That is, according to the present invention, with the simple configuration of the first and second control valves, there is an effect that not only anti-skid control but also hill hold control can be performed. If attention is paid only to the hillhold control, the control can be performed only with the first control valve.

Anti-skid control For example, when the slip condition of the wheels becomes higher than a predetermined value due to the driver's braking operation, a negative pressure chamber which exerts a normal boosting action (when the brake pedal is depressed) is provided. The pressure difference is made smaller than the pressure difference with the variable pressure chamber, and control is performed to weaken the boosting action of the brake booster.

More specifically, for example, the first control valve is shut off to prohibit the introduction of the atmosphere or the like into the transformer chamber.
The second control valve is set in a communication state, and control is performed so that the pressures of the variable pressure chamber and the negative pressure chamber become equal. Thereby, the pressure difference between the variable pressure chamber and the negative pressure chamber is reduced, so that the boosting action is reduced. Therefore, by reducing the master cylinder pressure and, consequently, the wheel cylinder pressure, the same control as the well-known pressure reduction control at the time of anti-skid control, that is, the force for suppressing the rotation of the wheels is reduced, and the excessive slip is suppressed to suppress the braking force Can be controlled.

Hill hold control Hill hold control means that when a driver stops on an uphill or downhill at a traffic light or the like, the brake force is maintained until the vehicle starts moving even if the driver depresses the brake pedal. Refers to control.

Therefore, in the present invention, for example, when the vehicle speed is reduced to 0 by depressing the brake pedal, the first control valve is shut off while the second control valve is shut off, so that the inside of the variable pressure chamber is changed. Pressure can be maintained. Therefore,
Even if the brake pedal is released, the pressure difference is maintained, so that a large master cylinder pressure due to the boosting action and a large wheel cylinder pressure are maintained, and the vehicle can be kept stationary. Accordingly, there is an effect that the vehicle does not move backward on the slope at the next start, and the operation during and after the stop is greatly facilitated.

In the brake booster according to the second aspect, FIG.
As illustrated in (b), in addition to the first and second mechanical valves, a first control valve is provided in the second communication path, and a fourth control path (communicating between the pressure source and the variable pressure chamber) is provided in the fourth communication path. Three control valves are provided. Further, the negative pressure chamber, the variable pressure chamber, the first and the second
The function of the mechanical valve is the same as that of the first aspect.

In particular, in the present invention, the second communication passage is provided with a first control valve for controlling the opening and closing of the second communication passage.
A fourth communication passage connecting the pressure source side and the transformation chamber side has a fourth communication passage.
A third control valve that controls opening and closing of the communication passage is provided. Therefore, by controlling the open / close state of the first and third control valves according to the command signal at the time of vehicle control, the pressure in the negative pressure chamber and the pressure in the variable pressure chamber are adjusted to generate or eliminate the pressure difference between the two chambers. , Whereby the onset or the stop of the boosting action can be controlled. Therefore, by controlling the boosting action, as described later in detail, traction control and other automatic brake control for suppressing wheel rotation and the hillhold control can be suitably performed.

That is, according to the present invention, the simple configuration of the first and third control valves has an effect that not only the automatic brake control but also the hillhold control can be performed. Automatic brake control For example, when the driving force of the wheel is large at the time of starting and the slip state of the wheel becomes more than a predetermined value, it exerts a boosting effect as if a normal brake pedal is depressed. Thus, the pressure difference between the negative pressure chamber and the variable pressure chamber is increased.

Specifically, for example, the first control valve is shut off to cut off the communication between the variable pressure chamber and the negative pressure chamber (via the first mechanical valve), and the third control valve is turned on. hand,
Introduce the atmosphere etc. into the transformer room. Thereby, the pressure difference between the variable pressure chamber and the negative pressure chamber increases, so that a boosting action can be exerted. Therefore, by increasing the master cylinder pressure and, consequently, the wheel cylinder pressure, for example, the same control as the well-known pressure increase control at the time of traction control, that is, suppressing the rotation of the wheels to suppress excessive slip and perform suitable acceleration. Can be.

If the wheel slip is greatly reduced by this control, the operations of the first and second control valves are reversed, and control is performed to reduce the boosting action, thereby maximizing the wheel slip rate. It can be adjusted to a suitable range suitable for. Hill Hold Control In the present invention, hill hold control can be performed in the same manner as in the first aspect.

For example, when the brake pedal is depressed and the vehicle speed becomes zero, the first control valve is shut off and the first control valve is turned off.
By setting the control valve to the shut-off state, it is possible to maintain the pressure in the variable pressure chamber, whereby a state in which a large boosting action can be similarly exerted. Therefore, even if the brake pedal is released, the stopped state of the vehicle can be maintained. Also, by setting the third control valve to the communication state,
It is also possible to exert a larger boosting action.

In the brake booster according to the third aspect, FIG.
As illustrated in (c), in addition to the first and second mechanical valves, a first control valve is provided in the second communication path, a second control valve is provided in the third communication path, and a fourth control valve is provided. A third control valve is provided in the communication passage. The functions of the negative pressure chamber, the variable pressure chamber, and the first and second mechanical valves are the same as those of the first and second aspects.

In particular, in the present invention, since the first to third control valves are provided in the second to fourth communication passages, respectively, the open / close state of each valve is controlled by a command signal, which will be described later in detail. As described above, automatic brake control such as anti-skid control and traction control, and hillhold control can be performed.

That is, according to the present invention, the simple configuration of the first to third control valves has an effect that not only anti-skid control and automatic brake control but also hill hold control can be performed. Anti-skid control For example, when the slip state of the wheel becomes a predetermined level or more due to a brake operation by the driver, the first control valve is shut off while the third control valve is shut off, and the air pressure to the transformer chamber is reduced. And the like are prohibited, and the second control valve is brought into a communicating state. Thereby, as described above, the pressure difference between the variable pressure chamber and the negative pressure chamber is reduced, and the boosting action is reduced, so that the pressure reduction control of the anti-skid control can be performed.

Further, the second control valve can be closed and the first or third control valve can be connected to restore the boosting action, thereby precisely adjusting the slip ratio of the wheels. Automatic brake control For example, when the driving force of the wheels is large at the time of starting or the like and the slip state of the wheels becomes a predetermined level or more, the first control valve is shut off while the second control valve is shut off. Then, the communication between the variable pressure chamber and the negative pressure chamber is cut off, and the third control valve is set in the communication state, so that the atmosphere or the like is introduced into the variable pressure chamber. As a result, a boosting action can be exerted, so that automatic brake control such as traction control can be performed.

Further, the third control valve is set to the shut-off state, and the first or second control valve is set to the communication state, so that the boosting action can be reduced, and the slip ratio of the wheel can be precisely adjusted. Hill Hold Control In the present invention, hill hold control can be performed in the same manner as in the first and second aspects.

For example, when the brake pedal is depressed and the vehicle speed becomes zero, the pressure in the variable pressure chamber is maintained by closing the first control valve while the second and third control valves are shut off. As a result, a state in which a similarly large boosting action can be exerted is achieved. Therefore, even if the brake pedal is released, the stopped state of the vehicle can be maintained.

In the brake booster according to the fourth aspect, a first control valve is provided in the second communication passage in addition to the first and second mechanical valves. The functions of the negative pressure chamber, the variable pressure chamber, and the first and second mechanical valves are the same as those of the first to third embodiments. In particular, in the present invention, since the first control valve is provided in the second communication passage, when the stop time detecting means detects the stop time of the vehicle, the first control valve is closed by the holding means and the brake is set. By maintaining the boosting function of the booster, hillhold control can be performed.

That is, according to the present invention, there is an effect that the hillhold control can be performed by the simple configuration of the first control valve. For example, when the vehicle speed becomes zero when the brake pedal is depressed, the pressure in the variable pressure chamber can be maintained by closing the first control valve, thereby also exerting a large boosting action. You can do it. Therefore, even if the brake pedal is released, the stopped state of the vehicle can be maintained.

(1) The anti-skid control and the automatic brake control using the brake booster described above are basically controls in which the master cylinder pressure is controlled and indirectly affects the wheel cylinder pressure. Therefore, when performing control using this brake booster, a device configuration for performing normal anti-skid control or automatic brake control, for example, a pressure increasing control valve that opens and closes a passage from a master cylinder to a wheel cylinder It is preferable to simultaneously control a pressure-reducing control valve that opens and closes a passage from the wheel cylinder to the reservoir.

(2) As means for releasing the hill hold, for example, when the start of the vehicle is detected based on the throttle opening or the depressed state of the accelerator pedal, the first control valve is brought into the communicating state to set the brake booster. Means to reduce the boosting action of (3) The content of the reduction of the boosting action not only means that the boosting action is reduced to some extent, but also includes a case where the boosting action is reduced and the boosting action is lost.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a brake booster according to the present invention will be described below in detail with reference to the drawings using examples (embodiments). First Embodiment a) First, a schematic configuration of a brake booster for an automobile (FF vehicle) that performs anti-skid control and hillhold control and a peripheral configuration thereof according to the present embodiment will be described with reference to FIG.

As shown in FIG. 2, a tandem-type master cylinder 2 is connected to the brake booster 1 of this embodiment, and the master cylinder 2 has a hydraulic pressure of X pipe (diagonal pipe). A hydraulic control circuit 3 for anti-skid control constituted by a system is connected.

The brake booster 1 utilizes the pressure difference between the negative pressure of the intake manifold (intake negative pressure) generated in the engine 4 and the atmospheric pressure, and adjusts the pressure difference as the brake pedal 6 is depressed. And master cylinder 2
A so-called boosting effect of increasing the force applied to the piston (not shown).

The brake booster 1 is provided with a variable pressure chamber 8 and a negative pressure chamber 9 partitioned by a diaphragm 7, and a first mechanical valve for adjusting the pressure in both chambers 8, 9. 11 and a second mechanical valve 12, and a first control valve 13 and a second control valve 14 are provided.

The first and second mechanical valves 11 and 12
Is a first communication path 16 communicating with the negative pressure chamber 9 from the external environment introducing the atmosphere via a branch point B1 (branching to the transformation chamber 8).
Are located in That is, the first mechanical valve 11 is disposed between the negative pressure chamber 9 and the branch point B1, and the second mechanical valve 12 is
It is arranged between the branch point B1 and the introduction section 17 for atmospheric pressure. The first and second mechanical valves 11 and 12 open and close mechanically with the operation of the push rod 19 of the brake pedal 6, and when the brake pedal 6 is not depressed, as shown in the figure. The first mechanical valve 11 is in a communicating state,
Although the second mechanical valve 12 is in a shut-off state, the brake pedal 6
Is depressed, the first mechanical valve 11 is shut off, the second mechanical valve 12 is in communication, and the first control valve 13 is disposed in the second communication passage 21 from the branch point B1 to the transformer chamber 8. An electromagnetic valve driven to a communication (OFF) or cut-off (ON) position by a signal from an electronic control unit (ECU; see FIG. 3) 22 at the time of anti-skid control or hill hold control described later. is there.

On the other hand, the second control valve 14 is disposed in a third communication passage 23 which communicates the variable pressure chamber 8 and the negative pressure chamber 9, and communicates in response to a signal from the ECU 22 during anti-skid control described later. This is an electromagnetic valve driven to two positions (on) or shut off (off). A check valve 24 is provided in the third communication passage 23 in parallel with the second control valve 14, and a pipe 26 that communicates the engine 4 with the negative pressure chamber 9 is also provided in the third communication passage 23.
A check valve 27 is provided.

The master cylinder 2 has a first hydraulic port 28 and a second hydraulic port 29, of which the first hydraulic port 28 is connected to the right front (FR) wheel via a first hydraulic pipe 31. The wheel cylinder (W / C) 36 of the left side and the wheel cylinder 37 of the rear left (RL) wheel are communicated. On the other hand, the second hydraulic port 29 is
2, the wheel cylinder 38 of the right rear (RR) wheel and the wheel cylinder 39 of the left front (FL) wheel are communicated.

The first hydraulic piping 31 has an FR-side pressure increasing control valve 41 and an FR-side pressure reducing control valve 46 for controlling the oil pressure of the wheel cylinder 36 of the FR wheel, and the oil pressure of the wheel cylinder 37 of the RL wheel. An RL side pressure increase control valve 42 and an RL side pressure reduction control valve 47 for controlling are provided.
The first hydraulic pipe 31 has a wheel cylinder 3
First reservoir 51 for releasing brake fluid from 6, 37
And a check valve 53 for releasing the brake fluid to the master cylinder 2 side when the pressure on the master cylinder 2 side decreases.

On the other hand, the second hydraulic pipe 32 has an RR-side pressure increasing control valve 43 and an RR-side pressure reducing control valve 48 for controlling the oil pressure of the RR wheel cylinder 38, and an FL wheel wheel cylinder 39. An FL-side pressure increasing control valve 44 and an FL-side pressure reducing control valve 49 for controlling hydraulic pressure are provided. Further, similarly to the first hydraulic pipe 31, the second reservoir 52 and the check valve 54 are provided in the second hydraulic pipe 32.
Is provided.

B) Next, the electrical configuration of this embodiment will be described with reference to FIG. As shown in FIG. 3, the ECU 22 that controls the brake booster 1 and the like includes a well-known CPU.
22a, ROM 22b, RAM 22c, input / output unit 22d
And a microcomputer having a bus line 22e and the like.

The input / output unit 22d includes a brake switch 56 for indicating that the brake pedal 6 has been depressed, a wheel speed sensor 57 for detecting the wheel speed of each wheel, and a throttle for detecting the opening of a switch lot valve (not shown). While the opening degree sensor 58 is connected, the first and second control valves 13 and 14, the pressure increasing control valves 41 to 44, and the pressure reducing control valve 4
6 to 49 are connected.

C) Next, the control processing of this embodiment executed by the ECU 22 will be described. First, the anti-skid control process will be described with reference to the flowchart of FIG. 4 and the explanatory diagram of FIG.

At step 100 in FIG. 4, it is determined whether or not the brake pedal 6 is depressed, based on whether or not the brake switch 56 is on. If the determination is affirmative, the process proceeds to step 110, whereas if the determination is negative, the process ends once. When the brake pedal 6 is depressed,
In conjunction with the movement of the push rod 19, mechanically, the first mechanical valve 11 enters the shut-off state, and the second mechanical valve 12 enters the communicating state. Accordingly, at this stage, while the negative pressure is being introduced into the negative pressure chamber 9, the atmospheric pressure is introduced into the variable pressure chamber 8 and the communication between the variable pressure chamber 8 and the negative pressure chamber 9 is interrupted. A pressure difference occurs between the chamber 8 and the negative pressure chamber 9, whereby
Normal boosting action is exerted.

In step 110, it is determined whether a condition for starting the anti-skid control is satisfied. For example, when the wheel slip ratio is equal to or more than a predetermined value, it is determined that the condition for starting the anti-skid control is satisfied. If the determination is affirmative, the process proceeds to step 120, whereas if the determination is negative, the process ends once.

Accordingly, in the following steps 120 and 130, anti-skid control using the brake booster 1 of the present embodiment is performed, that is, the wheel cylinders 36 to 130 are used.
In order to reduce the hydraulic pressure applied to 39, control is performed to reduce the boosting action. First, in step 120, the first control valve 13 is turned on to set it in the cutoff state, and the second communication path 21 is closed. As a result, the (first mechanical valve 12)
The introduction of the atmosphere is stopped.

In the following step 130, the second control valve 14
Is turned on to set the communication state, the third communication passage 23 is opened,
This processing is temporarily ended. As a result, air escapes from the high-pressure transformer chamber 8 to the low-pressure negative pressure chamber 9, so that the pressure difference between the two chambers 8, 9 is reduced, and the boosting action is reduced.

As described above, in this embodiment, when the condition for starting the anti-skid control is satisfied when the brake pedal 6 is depressed, as shown in FIG. 5, the first mechanical valve 11 is turned off, and the second mechanical valve 11 is turned off. The mechanical valve 12 is in communication with the first control valve 1
Since 3 is set to the shut-off state and the second control valve 14 is set to the communicating state, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is reduced, and the boosting action is reduced.

Therefore, since the master cylinder pressure and thus the wheel cylinder pressure are reduced, the conventional pressure reduction control valves 46 to
Similarly to the pressure reduction control of the anti-skid control by 49, the wheel cylinder pressure can be reduced. for that reason,
Since the slip ratio decreases, braking performance can be improved.

That is, in the present embodiment, the anti-skid control can be performed only by controlling the first and second control valves 13 and 14, so that the configuration and control are simplified. In this embodiment, the pressure reduction control of the wheel cylinder pressure is performed by setting the first control valve 13 to the shut-off state and the second control valve 14 to the communication state.
When the slip ratio is excessively reduced due to excessive pressure reduction, the wheel cylinder pressure is increased by returning the first control valve 13 to the communicating state and the second control valve 14 to the shutoff state, thereby increasing the wheel cylinder pressure. It is possible to control the slip ratio in a suitable range.

In this embodiment, the brake booster 1
Of the anti-skid control described above, but in addition to the control of the present embodiment, the open / close control of the pressure-increasing control valves 41 to 44 and the pressure-reducing control valves 46 to 49 is performed in a conventional manner to reduce and maintain the wheel cylinder pressure. Alternatively, a known anti-skid control for increasing the pressure may be performed. Incidentally, the timing of the anti-skid control by the pressure increase control valves 41 to 44 and the pressure reduction control valves 46 to 49 may be performed after the control for reducing the boosting action or may be performed simultaneously.

Next, the hillhold control will be described with reference to the flowchart of FIG. 6 and the explanatory diagram of FIG.
In step 200 of FIG. 6, whether or not the hill hold control is currently performed is determined by, for example, a flag (set at the start of the hill hold control). If the determination is affirmative, the process proceeds to step 240, and if the determination is negative, the process proceeds to step 210.

In step 210, it is determined whether or not the brake pedal 6 is depressed, based on whether or not the brake switch 56 is on. If a positive determination is made here, step 2
The process proceeds to step 20, and if a negative determination is made, the present process is temporarily terminated. As described above, the state in which the brake pedal 6 is depressed means that the atmosphere is introduced into the variable pressure chamber 8 via the second mechanical valve 12 and the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 increases the pressure. This is the state where the action is exhibited.

In step 220, it is determined whether the vehicle speed is 0 or not.
The determination is made based on the signal from the wheel speed sensor 57. If the determination is affirmative, the process proceeds to step 230, whereas if the determination is negative, the process is temporarily terminated. Step 230
Now, assuming that the condition for performing the hillhold control is satisfied, the first control valve 1
3 is turned on to be in the cutoff state, and the hillhold control is started.
This processing is temporarily ended.

As a result, the pressure in the variable pressure chamber 8 is maintained at a high pressure, so that the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is also maintained, and the boosting action is also maintained. Therefore, a high master cylinder pressure and thus a wheel cylinder pressure are maintained,
Even if the brake pedal 6 is returned on a slope, the vehicle does not move because the brake is applied.

On the other hand, in step 240, in which it is determined that the hill hold control is currently being performed in step 200, the process proceeds to step 240, in which it is determined whether or not the vehicle is ready to start. For example, it is determined whether or not the throttle opening is equal to or more than a predetermined value, based on a signal from the throttle opening sensor 58. If the determination is affirmative, the process proceeds to step 250. If the determination is negative, the hillhold control is directly performed. Then, the process is temporarily terminated.

In step 250, assuming that the condition for stopping the hill hold control is satisfied, the first control valve 13 is turned off and the communication state is established in the shut-off state of the second control valve 14, and the hill hold control is terminated. The process ends. As a result, the transformer chamber 8 is communicated with the outside world, so that when the brake pedal 6 is depressed, a large braking force can be exerted by utilizing the boosting action, similarly to the normal brake operation.
Conversely, when the brake pedal 6 is returned, the braking force is reduced.

As described above, in this embodiment, when the brake pedal 6 is depressed and the conditions for starting the hillhold control are satisfied, the first mechanical valve 11 is turned off as shown in FIG. , The second mechanical valve 12 is in the communicating state, and the second control valve 13
Is in the shut-off state, and the first control valve 13 is set in the shut-off state. Therefore, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained, and the hillhold control is started. On the other hand, when the brake pedal 6 is returned, the first mechanical valve 11 is in the communicating state and the second mechanical valve 12 is in the shut-off state as shown in FIG.
Since the second control valve 14 is in the shut-off state and the first control valve 13 is in the shut-off state, the pressure in the variable pressure chamber 8 is maintained, and the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained to boost the pressure. The action is exerted and the brake applied state is maintained.

Therefore, when waiting for a traffic light on a slope or the like, the brake is still applied even if the brake pedal 6 is returned, so that the vehicle does not move and the operation of the vehicle is simplified. That is, in the present embodiment, the first
Hillhold control can be performed only by controlling the control valve 13, and the configuration and control thereof are simplified. (Embodiment 2) Next, Embodiment 2 will be described. The brake booster of this embodiment differs from Embodiment 1 in that the second control valve is omitted and a third control valve is provided. Are different. The description of the same parts as in the first embodiment is omitted or simplified, and the same components are denoted by the same reference numerals.

A) As shown in FIG. 8, the brake booster 1 according to the present embodiment includes the first communication passage 16 similar to the first embodiment.
In addition to the first and second mechanical valves 11 and 12, the second communication passage 21 is provided with a first control valve 13. Particularly, in the present embodiment, a third control valve 62 is provided in the fourth communication passage 61 for introducing the atmosphere into the transformation chamber 8.

The third control valve 62 is switched to a cut-off (off) or communication (on) state by a control signal from the ECU 22. b) Next, the control processing of this embodiment executed by the ECU 22 will be described.

First, traction control processing, for example, acceleration slip control in the automatic brake control will be described with reference to the flowchart of FIG. 9 and the explanatory diagram of FIG. In step 300 of FIG. 9, it is determined whether or not the vehicle is accelerating, based on whether or not the throttle opening is equal to or greater than a predetermined value. If a positive determination is made here, step 3
The process proceeds to 10, and if a negative determination is made, the process is temporarily terminated.

At this time, since the brake pedal 6 is not depressed, the first mechanical valve 11 is in a communicating state and the second mechanical valve 12
Remain in the blocking state. Therefore, at this stage, the boosting action is not exerted. In step 310, it is determined whether a condition for starting the traction control is satisfied.
For example, when the slip ratio of the drive wheels becomes equal to or more than a predetermined value, it is determined that the traction control start condition is satisfied. If the determination is affirmative, the process proceeds to step 320, whereas if the determination is negative, the process is temporarily terminated.

Therefore, in the following steps 320 and 330, in order to perform traction control using the brake booster 1 of this embodiment, that is, the wheel cylinders 36 to 3
In order to increase the hydraulic pressure applied to 9, control for exerting a boosting action is performed. First, in step 320, the first control valve 13 is turned on to set the cutoff state, and the second communication path 21 is closed. As a result, the (second mechanical valve 11)
) The outflow of air is stopped.

In the following step 330, the third control valve 62
Is turned on to set the communication state, the fourth communication passage 61 is opened, and the present process is temporarily ended. Thereby, the fourth communication passage 6
Since the atmosphere is introduced into the transformation chamber 8 via the
The pressure difference at 9 increases, and thus a boosting action is exerted.

As described above, in this embodiment, when the condition for starting the traction control is satisfied at the time of the acceleration slip,
As shown in FIG. 10, the first mechanical valve 11 is in a communicating state, the second mechanical valve 12 is in a shut-off state, the first control valve 13 is in a shut-off state,
Since the third control valve 62 is set in the communication state, the variable pressure chamber 8
The pressure difference between the pressure and the negative pressure chamber 9 increases, and a boosting action is exerted. Therefore, since the master cylinder pressure and, consequently, the wheel cylinder pressure increase, it is possible to exert a force for suppressing the rotation of the wheels.

That is, in this embodiment, the wheel cylinder pressure required for traction control can be increased only by controlling the first and third control valves 13 and 62, and the configuration and control are simplified. This has the effect of being performed. still,
Since the traction control controls the acceleration slip, when the above-described control is performed by driving the brake booster 1, the pressure increase control valves 42 and 43 of the RL wheels and the RR wheels as the rolling wheels are set. Keep shut off.

Further, in this embodiment, the first control valve 13 is set to the shut-off state and the third control valve 62 is set to the communication state.
When the wheel cylinder pressure was increased, the pressure was excessively increased and the slip ratio was excessively reduced. Conversely, the first control valve 13 was returned to the open state, and the third control valve 14 was returned to the closed state. Thus, the wheel cylinder pressure can be reduced, and the slip ratio of the wheel can be controlled in a suitable range.

Further, in this embodiment, the brake booster 1
Traction control has been described, but in addition to the control of the present embodiment, a pump (not shown) and pressure increasing control valves 41 and 44 and pressure reducing control valves 46 and 49 may be controlled to perform well-known traction control for adjusting the wheel cylinder pressure.

Next, a description will be given of the hillhold control, which is basically the same as that of the first embodiment.
This will be briefly described with reference to FIG. In step 200 of FIG. 6, it is determined whether or not the hillhold control is currently being performed. Here, in step 210, which proceeds with a positive determination,
It is determined whether or not the brake pedal 6 has been depressed. If the determination is affirmative, the process proceeds to step 220.

In step 220, it is determined whether or not the vehicle speed is 0. In the advancing step 230 where the third control valve 62 is shut off, the first control valve 13 is turned on to shut off, the hillhold control is started, and the present process is ended once. On the other hand, in step 240, it is determined whether or not the vehicle is in a state of starting. In step 250, where the determination is affirmative, the first control valve 13 is turned off and the communication state is established in the shut-off state of the third control valve 62, the hillhold control is terminated, and the present process is temporarily terminated.

As described above, in the present embodiment, as shown in FIG. 11A, when the condition for starting the hillhold control is satisfied, the first mechanical valve 11 is in the shut-off state, and the second mechanical valve 12 is in the closed state. In the communication state, the third control valve 62 is shut off, and the first control valve 1
Since 3 is set to the cutoff state, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained. On the other hand, as shown in FIG. 11B, when the brake pedal 6 is returned, the first mechanical valve 11 is in a communicating state and the second mechanical valve 12 is in a shut-off state.
Since the third control valve 62 is in the cutoff state and the first control valve 13 is in the cutoff state, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained, and the braked state is maintained.

That is, in this embodiment, the hillhold control can be performed only by controlling the first control valve 13 as in the first embodiment. (Embodiment 3) Next, Embodiment 3 will be described. However, the brake booster of this embodiment is different from Embodiments 1 and 2 in that it has first to third control valves. The description of the same parts as those in the first and second embodiments is omitted or simplified, and the same components are denoted by the same reference numerals.

A) As shown in FIG. 12, the brake booster 1 of this embodiment has the first and second mechanical valves 11 and 12 in the first communication passage 16 as in the first and second embodiments. In addition, the first control valve 13 is provided in the second communication passage 21. In particular, in the present embodiment, the third communication between the variable pressure chamber 8 and the negative pressure chamber 9 is performed.
A second control valve 14 is provided in the communication passage 23, and a third control valve 62 is provided in the fourth communication passage 61 for introducing air into the variable pressure chamber 8.

That is, in this embodiment, the first and second embodiments are used.
Are provided with all of the first to third control valves 13, 14, and 62. b) Next, the control processing of this embodiment executed by the ECU 22 will be described.

First, the anti-skid control process will be described. Since the process is basically the same as that of the first embodiment,
A brief description will be given with reference to FIGS. In step 100 of FIG. 4, it is determined whether or not the brake pedal 6 has been depressed. Here, the affirmatively determined step 110
Then, it is determined whether or not a condition for starting the anti-skid control is satisfied. If a positive determination is made here, step 1
Go to 20.

In step 120, the first control valve 13 is turned on to set it to the shut-off state, and the second communication passage 21 is closed. In the following step 130, the second control valve 14 is turned on to set it to the communication state. Then, the third communication path 23 is opened, and the present process is temporarily ended. Note that, at this time, the third control valve 62 remains off and shut off.

As described above, in this embodiment, when the condition for starting the anti-skid control is satisfied when the brake pedal 6 is depressed, the first mechanical valve 11 is turned off, the second mechanical valve 11 is turned off, as shown in FIG. The mechanical valve 12 is in the communicating state, and the third control valve 62
Is set to the shut-off state, the first control valve 13 is set to the cut-off state, and the second control valve 14 is set to the communication state, so that the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is reduced, and the boosting action is reduced. I do.

Therefore, since the master cylinder pressure and hence the wheel cylinder pressure are reduced, anti-skid control can be executed. Next, a traction control process will be described. Since the traction control process is basically the same as that of the second embodiment, the traction control process will be briefly described with reference to FIGS.

At step 300 in FIG. 9, it is determined whether or not the vehicle is in an acceleration state. Here, in step 310, which proceeds with an affirmative determination, it is determined whether a condition for starting the traction control is satisfied. If the determination is affirmative, the process proceeds to step 320. In step 320, the first control valve 1
3 is set to a cut-off state, the second communication passage 21 is closed, and in a subsequent step 330, the third control valve 62 is set to a communication state by turning on, and the fourth communication passage 61 is opened to temporarily This processing ends. At this time, the second control valve 14 is kept in the shut-off state, and the pressure increase control valves 42 and 43 of the RL wheels and the RR wheels, which are the rolling wheels, are shut off to connect the pipes to the rolling wheels. Road is blocked.

As described above, in this embodiment, when the condition for starting the traction control is satisfied during the acceleration slip,
As shown in FIG. 14, the first mechanical valve 11 is in the communicating state, the second mechanical valve 12 is in the shut-off state, and the second control valve 14 is in the shut-off state.
Since the first control valve 13 is set to the shut-off state and the third control valve 62 is set to the communication state, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 increases, and the boosting action is exerted.

Therefore, since the master cylinder pressure and, consequently, the wheel cylinder pressure increase, traction control on the drive wheels can be executed. Next, the hillhold control will be described. Since the hillhold control is basically the same as that of the first embodiment, it will be briefly described with reference to FIGS. In step 200 of FIG.
It is determined whether the hill hold control is currently being performed. Here, in step 210, where a negative determination is made, the process determines whether or not the brake pedal 6 has been depressed. On the other hand, in step 220 where the determination is affirmative, the process determines whether the vehicle speed is zero. If the determination is affirmative, the process proceeds to step 230.

In step 230, when the second control valve 14 and the third control valve 62 are shut off, the first control valve 13 is turned on to shut off, the hillhold control is started, and the present process is ended once. On the other hand, in step 240, it is determined whether or not the vehicle is in a state of starting. In step 250 where the determination is affirmative, the first control valve 13 is turned off and the communication state is established when the second control valve 14 and the third control valve 62 are shut off, and the hillhold control is terminated. finish.

As described above, in this embodiment, as shown in FIG. 15A, when the condition for starting the hillhold control is satisfied, the first mechanical valve 11 is in the shut-off state, and the second mechanical valve 12 is in the closed state. Since the communication state is set, the second control valve 14 and the third control valve 62 are set in the cutoff state, and the first control valve 13 is set in the cutoff state, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained. . On the other hand, FIG.
As shown in FIG. 5B, when the brake pedal 6 is returned, the first mechanical valve 11 is in the communicating state and the second mechanical valve 12 is in the shutoff state, but the second control valve 14, the third control Since the valve 62 and the first control valve 13 are shut off, the pressure difference between the variable pressure chamber 8 and the negative pressure chamber 9 is maintained, and the braked state is maintained.

That is, in this embodiment, the first and second embodiments are used.
Similarly, the hillhold control can be performed only by controlling the first control valve 13. It is needless to say that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the technical scope of the present invention.

(1) For example, in the second and third embodiments, the traction control has been described as the control of the automatic brake. However, the present invention can be applied to the following control. For example, if there is a sensor that detects an obstacle, a brake booster can be used to apply a brake to all the wheels to avoid a collision or reduce the impact of a collision.

Further, if there is a steering wheel angle sensor, a yaw rate sensor, or the like, when a vehicle is about to spin or understeer, an appropriate moment is generated in a direction to cancel the behavior so that a corresponding wheel is automatically generated. By applying the brake, it is possible to prevent contact with an oncoming vehicle or the like caused by swelling at a corner or the like of the vehicle.

(2) In addition to the hydraulic control circuits of the first to third embodiments, for example, a hydraulic control circuit as shown in FIG. 16 can be employed. For example, the hydraulic control circuit of FIG. 16A has one hydraulic control valve disposed for each wheel cylinder. The hydraulic control circuit of FIG. And a pump for sucking brake fluid from the reservoir to the master cylinder side.

(3) The degree of effectiveness of the brake booster is adjusted by adjusting the open / closed state or the degree of opening of the first to third control valves, for example, by changing the duty ratio. be able to. (4) Further, in the first to third embodiments, the brake booster using the engine negative pressure and the atmospheric pressure has been described as an example. However, as the brake booster, another brake booster such as an accumulator may be used. The one using a pressure source can be adopted.

[Brief description of the drawings]

FIG. 1 is a view for explaining a brake booster and an operation thereof according to the present invention, wherein (a) is an explanatory view of the invention of claim 1;
(B) is an explanatory view of the invention of claim 2, and (c) is an explanatory view of the invention of claim 3.

FIG. 2 is a schematic configuration diagram illustrating a brake booster and a peripheral configuration thereof according to the first embodiment.

FIG. 3 is a block diagram illustrating an electrical configuration of the first embodiment.

FIG. 4 is a flowchart illustrating anti-skid control according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating an operation at the time of anti-skid control of the brake booster of the first embodiment.

FIG. 6 is a flowchart illustrating hillhold control according to the first embodiment.

FIG. 7 is an explanatory diagram showing an operation at the time of hillhold control of the brake booster of the first embodiment.

FIG. 8 is a schematic configuration diagram illustrating a brake booster according to a second embodiment and a peripheral configuration thereof.

FIG. 9 is a flowchart illustrating traction control according to the second embodiment.

FIG. 10 is an explanatory diagram showing an operation at the time of traction control of the brake booster of the second embodiment.

FIG. 11 is an explanatory diagram showing an operation at the time of hillhold control of the brake booster of the second embodiment.

FIG. 12 is a schematic configuration diagram illustrating a brake booster and a peripheral configuration thereof according to a third embodiment.

FIG. 13 is an explanatory diagram showing an operation during anti-skid control of the brake booster of the third embodiment.

FIG. 14 is an explanatory diagram illustrating an operation during traction control of the brake booster of the third embodiment.

FIG. 15 is an explanatory diagram showing an operation at the time of hillhold control of the brake booster of the third embodiment.

FIG. 16 is a circuit diagram showing another hydraulic control circuit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 brake booster 2 master cylinder 3 hydraulic control circuit 4 engine 6 brake pedal 11 first mechanical valve 12 second mechanical valve 13 first control valve 14 second control valve 16 first Communication passage 21 Second communication passage 23 Third communication passage 36, 37, 38, 49 Wheel cylinder 61 Fourth communication passage 62 Third control valve

Claims (4)

[Claims] A negative pressure chamber into which a negative pressure is introduced from a negative pressure source; a variable pressure chamber through which ventilation is performed from a pressure source higher than the negative pressure source; a pressure source side and the negative pressure chamber side; And a first mechanical valve and a second mechanical valve that are provided in the first communication passage and that are mechanically driven in response to a brake operation by a driver to open and close the first communication passage. A first communication passage between the first mechanical valve and the second mechanical valve and a second communication passage communicating with the variable pressure chamber side, wherein an operating force applied to a brake pedal by the brake operation is reduced. A brake booster for boosting and adding to a brake fluid on a master cylinder side, wherein a first control is provided in the second communication passage and controls opening and closing of the second communication passage in response to a command signal at the time of vehicle control. A valve provided in a third communication passage communicating between the negative pressure chamber and the variable pressure chamber; Depending on your time of command signal, a second control valve for opening and closing control of the third communication passage, the brake booster, characterized in that it comprises a. 2. A negative pressure chamber into which a negative pressure is introduced from a negative pressure source, a variable pressure chamber through which ventilation is performed from a pressure source higher than the negative pressure source, and a pressure source side and the negative pressure chamber side. A first communication valve which is provided in the first communication passage, is mechanically driven in response to a driver or a brake operation of an automatic brake, and opens and closes the first communication passage; and A two-mechanical valve; and a second communication passage communicating between the first mechanical valve and the second mechanical valve and the side of the variable pressure chamber. A brake booster for boosting and adding to a brake fluid on a master cylinder side, wherein a first control is provided in the second communication passage and controls opening and closing of the second communication passage in response to a command signal at the time of vehicle control. A valve provided in a fourth communication passage communicating between the pressure source side and the variable pressure chamber side; Depending on your time of command signal, a third control valve for opening and closing control of the fourth communication passage, the brake booster, characterized in that it comprises a. 3. A negative pressure chamber into which a negative pressure is introduced from a negative pressure source, a variable pressure chamber through which ventilation is performed from a pressure source higher than the negative pressure source, a pressure source side and the negative pressure chamber side, A first communication valve which is provided in the first communication passage, is mechanically driven in response to a driver or a brake operation of an automatic brake, and opens and closes the first communication passage; and A two-mechanical valve; and a second communication passage communicating between the first mechanical valve and the second mechanical valve and the side of the variable pressure chamber. A brake booster for boosting and adding to a brake fluid on a master cylinder side, wherein a first control is provided in the second communication passage and controls opening and closing of the second communication passage in response to a command signal at the time of vehicle control. A valve provided in a third communication passage communicating between the negative pressure chamber and the variable pressure chamber; A second control valve for controlling the opening and closing of the third communication passage in response to a command signal at the time of control; and a fourth communication passage provided in the fourth communication passage for communicating between the pressure source side and the variable pressure chamber side. A third control valve for controlling the opening and closing of the fourth communication passage in response to a command signal. 4. A negative pressure chamber into which a negative pressure is introduced from a negative pressure source, a variable pressure chamber through which ventilation is performed from a pressure source higher than the negative pressure source, and a pressure source side and the negative pressure chamber side. And a first mechanical valve and a second mechanical valve that are provided in the first communication passage and that are mechanically driven in response to a brake operation by a driver to open and close the first communication passage. A first communication passage between the first mechanical valve and the second mechanical valve and a second communication passage communicating with the variable pressure chamber side, wherein an operating force applied to a brake pedal by the brake operation is reduced. A brake booster for boosting and adding to a brake fluid on a master cylinder side, wherein a first control is provided in the second communication passage and controls opening and closing of the second communication passage in response to a command signal at the time of vehicle control. A valve, a stop time detecting means for detecting when the vehicle is stopped, and a stop time detecting means. Holding means for holding the function of boosting the brake booster by setting the first control valve to a shut-off state when both stop times are detected; .