JPH06191394A - Brake booster device - Google Patents

Abstract

PURPOSE:To ensure higher responsibility and reliable fail safe in terms of a brake booster device for which suction negative pressure in an internal combus tion engine is used as driving source. CONSTITUTION:First and second control B/Bs 31, 32 is constituted by negative pressure rooms 31a, 32a where suction negative pressure is stored, transformer rooms 31b, 32b to hold preset inner pressure by introducing suction negative pressure and the atmospheric pressure from time to time, master cylinders 31c, 32c to transform thrust corresponding to differential pressure therebetween to oil pressure in brake mechanisms 6-9. When the first control B/B 31 is in normal operation, the third shutoff valve 36 is opened to function the second control B/B 32 as a vacuum tank for restraining the change of inner pressure in the negative pressure room 31a right after the atmospheric pressure is introduced. When the first control B/B 31 is in failure, the third shutoff valve 36 is closed to increase brake pressure with the second control B/B 32 since then.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake booster device, and more particularly to a brake booster device which increases a brake operating force by using a differential pressure between an intake negative pressure and an atmospheric pressure generated in an internal combustion engine as a drive source.

[0002]

2. Description of the Related Art Conventionally, there is known a brake booster device for increasing a brake operating force by using an intake negative pressure generated in an internal combustion engine as a drive source (Japanese Patent Laid-Open No. 61-175130).
Issue).

The device described in the above publication has a negative pressure chamber capable of accumulating the intake negative pressure of the internal combustion engine and holding it at an internal pressure equal to the intake negative pressure, and an intake negative pressure and the atmosphere as appropriate to set a predetermined internal pressure. A brake booster consisting of a variable pressure chamber that can be set to a negative pressure and a piston at a position separating the negative pressure chamber and the variable pressure chamber, and a master cylinder that converts the differential pressure generated between them into hydraulic pressure. There is.

The piston of this master cylinder is connected to a push rod that applies pressure to the brake fluid supplied to the brake mechanism arranged for each wheel. Therefore, for example, when the negative pressure chamber and the variable pressure chamber are held at equal pressure,
The brake mechanism does not operate because no force acts on the piston. On the other hand, if the pressure in the variable pressure chamber is kept at atmospheric pressure while the negative pressure chamber is maintained at negative pressure, a thrust force corresponding to the differential pressure acts on the piston, that is, the push rod, and each brake mechanism is boosted to a pressure corresponding to that thrust force. The brake pressure is supplied.

That is, according to the brake booster device described in the above publication, the hydraulic pressure corresponding to the differential pressure between the negative pressure chamber and the variable pressure chamber is supplied to each brake mechanism, and the variable pressure chamber is opened to the atmosphere. As a result, the hydraulic pressure can be reliably increased, and the pressure increase rate can be easily controlled by controlling the amount of air introduced into the variable pressure chamber.

[0006]

However, in the above-mentioned conventional apparatus, since the negative pressure capacity that can be stored in the negative pressure chamber is small, the atmosphere of the master cylinder is introduced into the variable pressure chamber so that the piston of the master cylinder is on the negative pressure chamber side. When it shifts to, the negative pressure in the negative pressure chamber temporarily decreases accordingly. Therefore, the differential pressure generated between the variable pressure chamber and the negative pressure chamber is reduced, and the generation of the brake pressure supplied to each brake mechanism is hindered.

Particularly in a region where the intake negative pressure of the internal combustion engine is small, it is difficult to obtain a differential pressure required to secure a desired braking force, and the inflow velocity of air when the variable pressure chamber is opened to the atmosphere is slow. That is, the unresponsiveness is more remarkably exposed. As described above, the conventional brake booster device has a problem in that the responsiveness of the brake pressure to the driver's operation cannot be sufficiently ensured.

Further, in the above-mentioned conventional brake booster device, the brake pressure supplied to the brake mechanism is all generated by the brake booster, and a sufficient braking force can be obtained when the only brake booster fails. It also had the problem of disappearing.

The present invention has been made in view of the above points, and a plurality of brake boosters are arranged in a state where the negative pressure chambers are communicated with each other to secure a sufficient negative pressure capacity and to cause some abnormalities. It is an object of the present invention to provide a brake booster device capable of improving responsiveness and ensuring secure fail-safe by continuing control with a normal brake booster in the case of occurrence of.

[0010]

FIG. 1 shows the principle of a brake booster device which achieves the above object.

In FIG. 1, reference numeral M1 indicates a first brake booster, and reference numeral M2 indicates a second brake booster.
The first and second brake boosters M1 and M2 store negative pressure chambers M1a and M2a that store negative pressure supplied from a negative pressure supply source.
And variable pressure chambers M1b and M2b capable of holding a predetermined internal pressure by appropriately introducing the negative pressure supplied from the negative pressure supply source and the atmosphere,
The master cylinders M1c and M2c are configured to convert the thrust force corresponding to the differential pressure generated between the negative pressure chambers M1a and M2a and the variable pressure chambers M1b and M2b into the hydraulic pressure of the brake mechanism M3.

A negative pressure chamber M1a of the first brake booster M1 and a negative pressure chamber M2a of the second brake booster M2.
And are connected by a communication passage M5 having a control valve M4. The abnormality detecting means M6 monitors the first and second brake boosters M1 and M2, and when one of the abnormality is detected, sends an abnormality detection signal to the abnormal time control means M7. When abnormality of one brake booster is detected, the abnormality control means M7 closes the control passage M5 by closing the control valve M4 and stops the supply of hydraulic pressure from the one brake booster to the brake mechanism M3. Let

[0013]

In the brake booster device according to the present invention,
When the first and second brake boosters M1 and M2 are functioning normally, the control valve M4 is open.
Therefore, when the negative pressure chambers M1a and M2a are in a conductive state and the variable pressure chambers M1b and M2b are not open to the atmosphere, negative pressure is accumulated in the negative pressure chambers M1a and M2a and the variable pressure chambers M1b and M2b. Become.

Therefore, when increasing the brake pressure, the variable pressure chamber M1b
If the configuration is such that the atmosphere is introduced into only the negative pressure chamber M1a of the first brake booster M1, the negative pressure chamber M2a and the variable pressure chamber M2b of the second brake booster M2 act as a vacuum tank, and Negative pressure fluctuation is suppressed. Therefore, even in a region where the intake negative pressure of the internal combustion engine is low, good responsiveness to the driver's operation is ensured.

When an abnormality occurs in the first or second brake booster M1, M2, the communication passage M5 is cut off, and the negative pressure chamber M1a of the first brake booster M1 and the second brake booster M2 are separated. The negative pressure chamber M2a is separated, and the supply of hydraulic pressure from the brake booster on the failed side to the brake mechanism M3 is stopped.

That is, when an abnormality occurs in the first or second brake boosters M1 and M2, the brake booster on the failed side thereafter is in a state of being disconnected from the brake booster device. Therefore, the brake booster on the failed side does not have any influence on the brake booster device. On the other hand, the function of the brake booster device is continuously maintained by the brake booster on the normally functioning side, and safety is secured even in the event of an abnormality.

[0017]

FIG. 2 is a block diagram of a brake system incorporating an embodiment of a brake booster device according to the present invention. It should be noted that this system includes the brake booster device according to the present invention for a physically handicapped person, and also has a general brake mechanism for exerting a braking force according to the depression force of the brake pedal for a healthy person.

In FIG. 2, reference numeral 1 indicates an electronic control unit (control ECU) including the internal pressure control means described above. Control EC
A mode changeover switch 2 for changing over the disabled mode / healthy person mode is connected to U1, and the output signal of this mode changeover switch 2 determines whether or not to activate the brake booster device of this embodiment.

Reference numerals 3 and 4 respectively represent a vehicle speed sensor which outputs a pulse signal corresponding to the vehicle speed and an engine speed sensor which outputs a pulse signal corresponding to the rotation speed of the internal combustion engine. Reference numeral 5 indicates an operation lever in the physically disabled mode. The operation lever 5 is used to instruct acceleration / deceleration of the vehicle, and supplies a predetermined acceleration / deceleration instruction amount signal to the control ECU 1 by a driver's operation.

In FIG. 1, FL, FR and RL, RR respectively indicate the left and right front wheels and the left and right rear wheels of the vehicle. Each of these wheels is independently provided with a brake mechanism 6 to 9 which operates by hydraulic pressure to brake each wheel. The brake mechanisms 6 to 9 are set to exert a braking force only when the supplied hydraulic pressure becomes high.

Further, the left and right front wheels FL, FR are provided with hydraulic pressure sensors 10, 11 for detecting the actual brake pressure actually supplied to the brake mechanisms 6-9. And
These hydraulic pressure sensors 10 and 11 supply an actual brake pressure signal corresponding to the detected hydraulic pressure to the control ECU 1.

By the way, in the present embodiment, the throttle valve 13 for controlling the amount of intake air supplied to the internal combustion engine.
The opening degree of is adjusted electronically. In the handicapped person mode, not only the braking force but also the driving force is operated.
This is because the configuration can be adjusted by.

Reference numeral 20 indicates an electronically controlled throttle used in this embodiment. The electronic control throttle 20 includes a DC motor 21 as a drive source, and adjusts the opening of the throttle valve 13 based on a throttle opening signal output from the control ECU 1 according to the acceleration / deceleration instruction amount supplied from the operation lever 5. I do.

That is, the throttle valve 13 in the apparatus of this embodiment has the control ECU 1 in addition to the accelerator pedal 12.
It is also driven by the DC motor 21 that is driven by. Here, the other end of the wire 14 connected to the throttle valve 13 is connected to a shaft 23 that rotates in conjunction with an electromagnetic clutch 22 that transmits the rotation of the DC motor 21.

Therefore, the electromagnetic clutch 22 is the DC motor 2
When connected to 1, the wire 14 opens and closes the throttle valve 13 as the DC motor 21 rotates, and the opening of the throttle valve fluctuates.
The electromagnetic clutch 22 operates according to a control signal supplied from the control ECU 1 to disconnect or connect the DC motor 21 and the throttle valve 13. When the electromagnetic clutch 22 is disengaged, the throttle valve will no longer open in accordance with the rotation of the DC motor 21.

Further, the electronically controlled throttle 20 has a structure shown in FIG.
As shown in FIG. 5, an opening sensor 24 for detecting the actual opening of the throttle valve based on the rotation angle of the shaft 23 is incorporated. Then, the opening sensor 24 sends the detected actual opening data of the throttle valve to the control ECU 1.

The configuration of the electronically controlled brake system, which is the main part of this embodiment, will be described below. As described above, the device of this embodiment is premised on being installed in the vehicle for the physically handicapped. Here, ensuring good operability is one of the important issues when designing a vehicle for a physically handicapped person. Among them, operability when braking the vehicle is the most important item from the viewpoint of ensuring safety.

Therefore, in this embodiment, in order to secure a reliable braking force with a slight operating force, the actual brake pressure supplied to the brake mechanisms 6 to 9 arranged on each wheel can be electrically controlled. Uses an electronically controlled braking system.

In FIG. 2, reference numerals 31 and 32 are the above-mentioned first numbers.
And a first control brake booster corresponding to the second brake booster (hereinafter abbreviated as the first control B / B. The same applies to the second control brake booster) and the second.
B / B for control is shown. B / B for these first and second controls
As shown in FIG. 1, reference numerals 31 and 32 respectively denote negative pressure chambers 31.
a, 32a, transformation chambers 31b, 32b, master cylinder 3
It is composed of 1c and 32c.

These negative pressure chambers 31a and 32a communicate with the downstream of the intake pipe throttle valve (not shown) of the internal combustion engine 35 via the first shutoff valve 33 and the second shutoff valve 34, respectively, and also the third shutoff valve. They communicate with each other via a valve 36.

On the other hand, the variable pressure chambers 31b and 32b are respectively provided with the first and second pressure increasing valves 37 and 38 and the air filters 39 and 40.
Through the first pressure reducing valve 41 and the second pressure reducing valve 42 and the negative pressure chambers 31a, 32a.

Therefore, the pressure in the variable pressure chambers 31b and 32b is set to the negative pressure chamber 31a by closing the first pressure increasing valve 37 and the second pressure increasing valve 38 and opening the first pressure reducing valve 41 and the second pressure reducing valve 42. Three
The pressure becomes equal to the internal pressure of 2a, and when the first pressure increasing valve 37 and the second pressure increasing valve 38 are opened and the first pressure reducing valve 41 and the second pressure reducing valve 42 are closed, the pressure becomes atmospheric pressure.

The shutoff valves 33, 34, 36, the pressure increasing valves 37, 38, and the pressure reducing valves 41, 42 are used as control ECUs.
Upon receiving the cutoff signal, the pressure increase signal, and the pressure decrease signal supplied from No. 1, the internal pressure of the negative pressure chambers 31a and 32a and the variable pressure chambers 31b and 32b is adjusted by appropriately opening or closing the valves.

Here, the negative pressure chambers 31a and 32a and the variable pressure chamber 3
A piston or a diaphragm that separates these spaces is arranged between the spaces 1b and 32b. These pistons and the like are connected to the push rods of the master cylinders 31c and 32c.

On the other hand, the internal combustion engine 3 is installed in the negative pressure chambers 31a and 32a.
The variable pressure chambers 31b and 32b in the state where the intake negative pressure of 5 is stored.
When the atmosphere is introduced into the negative pressure chambers 31a, 32a and the variable pressure chambers 31b, 32b, a differential pressure is generated between the negative pressure chambers 31b, 32b from the variable pressure chambers 31b, 32b side. A thrust force toward the side of 31a, 32a is generated.

Therefore, the variable pressure chambers 31b and 32b and the negative pressure chamber 3
When a pressure difference occurs between the master cylinders 31a and 32a, a thrust force corresponding to the pressure difference is generated in the push rods of the master cylinders 31c and 32c, and the hydraulic pressure in the master cylinders 31c and 32c is increased.

On the other hand, when the internal pressures of the variable pressure chambers 31b and 32b are kept equal to the internal pressures of the negative pressure chambers 31a and 32a,
No force acts on the piston or diaphragm that separates those spaces. Therefore, the transformer room 31b, 32
When a sufficient intake negative pressure is stored in b, the hydraulic pressure in the master cylinders 31a and 32a is not increased.

By the way, the master cylinders 31c, 32c
The hydraulic pressure generated in 1 is guided to the high pressure selection valves 43a and 43b that form the change valve 43. These high-pressure selection valves 43a and 43b are valve mechanisms that select the higher hydraulic pressure of the two hydraulic pressures supplied to the two inlets and send it to the outlets.

Further, the hydraulic pressures flowing out from the high pressure selection valves 43a and 43b are introduced to the inlets of the high pressure selection valves 44a and 44b, which form another change valve 44, respectively. The high pressure selection valves 44a and 44b also have two inflow ports like the high pressure selection valves 43a and 43b.
The outlet of the master cylinder 16 that generates hydraulic pressure in conjunction with the brake pedal 15 communicates with the inlet on the side not communicating with the high pressure selection valves 43a and 43b.

The hydraulic pressure flowing out from the change valve 44 is transmitted to the brake mechanisms 6-9 arranged on each wheel. A known anti-lock brake system (ABS) is incorporated in the brake system of this embodiment, and the hydraulic pressure transmitted from the change valve 44 is AB.
It is supplied to each brake mechanism 6-9 through the S mechanism 17.

Here, the brake pedal 15 and the master cylinder 16 are a brake mechanism provided corresponding to the mode for the physically handicapped person, but the mode selector switch 2 selects the mode for the physically handicapped person in order to ensure safety. Even if it is, it is maintained in an operable state. Therefore, when the physically disabled mode is selected in the device of the present embodiment, the highest pressure among the hydraulic pressures applied by the first and second control B / Bs 31, 32 or the brake pedal 15 is the brake mechanism. 6 to 9 will be supplied.

On the other hand, when the healthy person mode is selected by the mode selector switch 2, it is necessary to prevent the electronically controlled brake from operating due to an erroneous operation of the operation lever 5. Therefore, when the healthy person mode is selected in the device of the present embodiment, the first and second pressure reducing valves 41, 42 are opened, and the negative pressure chambers 31a, 32a and the variable pressure chambers 31b, 32b are opened.
And are held at equal pressure. Therefore, the brake pressure is not increased by the first and second control B / Bs 31 and 32, and even if the operating lever 5 is erroneously operated, the brake boost function does not operate.

In FIG. 2, reference numerals 18 and 19 denote a brake lamp and a mode display lamp, respectively, which are connected to the control ECU 1, and are lit according to the states of the brake mechanisms 6 to 9 and the mode changeover switch 2, respectively. To do.

FIG. 3 shows a flowchart of a main routine executed by the control ECU 1 of the brake booster device of this embodiment. The operation of the apparatus of this embodiment will be described below with reference to FIG.

When the main routine shown in FIG. 3 is started,
First, in step 100, an initial brake check is performed.
This brake initial check is performed to confirm whether or not the first and second control B / Bs 31, 32 are functioning normally in the initial state. FIG. 4 shows a flowchart of a subroutine of this brake initial check.
The brake initial check processing will be described below with reference to FIG.

When the brake initial check routine is started, step 300 is executed first and the first step in FIG.
And negative pressure chambers 31a, 32 of the second control B / Bs 31, 32
The third shutoff valve 36 is closed to separate a. Then, while maintaining this state, first, the first control B / B3
Perform the function check of 1.

In step 310, the first control B / B3
Preparations for the function check 1 are made. That is,
In order not to be affected by the second control B / B 32, the second pressure increasing valve 38 is closed and the second pressure reducing valve 42 is opened so that the thrust due to the differential pressure is not generated in the master cylinder 32c. At the same time, the second shutoff valve 34 is closed to close the second control B.
/ B32 is substantially separated from the apparatus of this embodiment. Then, since the intake negative pressure of the internal combustion engine 35 is supplied to the negative pressure chamber 31a of the first control B / B 31, the first shutoff valve 3
Open valve 3.

Next, at step 320, the first pressure increasing valve 3
7 is opened, and the first pressure reducing valve 41 is closed. Therefore, the internal pressure of the negative pressure chamber 31a approaches the intake negative pressure of the internal combustion engine 35, and the internal pressure of the variable pressure chamber 31b approaches the atmospheric pressure. If the first control B / B31 is normal, the master cylinder 31c Due to the action, the increased brake pressure is supplied to the brake mechanisms 6-9.

Therefore, at step 330, it is judged if the actual brake pressure BPR detected by the hydraulic pressure sensors 10 and 11 has reached a predetermined judgment value KFBP1.
If BPR ≧ KFBP1 is satisfied, it is determined that the hydraulic pressure increasing function of the first control B / B 31 is normal, and the process proceeds to step 340.

In steps 340 and 350,
The pressure reducing function of the first control B / B 31 is checked. That is, in step 340, the first pressure increasing valve 37 is closed and the first pressure reducing valve 41 is opened to create a condition that the internal pressure of the variable pressure chamber 31b and the internal pressure of the negative pressure chamber 31a are equal. .

Therefore, if the pressure reducing function of the first control B / B 31 is functioning normally, the brake pressure supplied to the brake mechanisms 6 to 9 will not be increased, and the pressure sensor 1
The actual brake pressure BPR detected at 0 and 11 should be 0. Therefore, in step 350, BPR = 0
It is determined whether or not.

When BPR = 0 holds, it is judged that the first control B / B 31 is functioning normally, and the routine proceeds to step 360, where the functional state of the first control B / B 31 is set. "0" is set to the flag XFB1 representing the flag, and the function check of the first control B / B 31 is completed.

On the other hand, in step 330, the BPR
<If it is determined that KFBP1 is satisfied, or if BPR ≠ 0 is determined at step 350,
In any case, it can be determined that an abnormality that seriously affects the brake mechanisms 6 to 9 has occurred in the first control B / B 31. For this reason, in the present embodiment, without distinguishing the two, if they are determined to be abnormal, it is equally determined to be a failure, and in step 370, the flag XFB1 is set to "1".

After the function check of the first control B / B 31 is completed in this way, the second control B / B 32 is then continued.
Check the function of.

Since it is necessary to keep the first control B / B 31 separated from the apparatus of this embodiment, the first pressure increasing valve 37 is closed and the first pressure reducing valve 41 is opened in step 380. Thus, the master cylinder 31c creates a state in which the hydraulic pressure is not increased, and further the first cutoff valve 33 is closed to stop the supply of the intake negative pressure to the negative pressure chamber 31a. And the second
The shutoff valve is opened to supply the intake negative pressure of the internal combustion engine 35 to the negative pressure chamber 32a.

Here, in the above step 310, the second
Since the pressure increasing valve 38 is closed and the second pressure reducing valve 42 is opened, when an intake negative pressure is supplied to the negative pressure chamber 32a, the negative pressure is not limited to the negative pressure chamber 32a. Transformer room 3
It will be stored in 2b.

Therefore, when the second pressure increasing valve 38 is opened and the second pressure reducing valve 42 is closed in step 390, the negative pressure chamber 31a stores the negative pressure of the internal combustion engine 35, and the inside of the variable pressure chamber 32b. Becomes atmospheric pressure. Therefore, if the second control B / B 32 is normal, the hydraulic pressure increased according to the differential pressure generated between the negative pressure chamber 32a and the variable pressure chamber 32b in the master cylinder 32c is the brake mechanism 6-9. Will be supplied to.

Therefore, in step 400, the oil pressure sensor 1
The actual brake pressure BPR detected at 0 and 11 is compared again with the predetermined determination value KFBP. If BPR ≧ KFBP is satisfied, the hydraulic pressure increasing function of the second control B / B 32 is normal. Deciding.

If it is determined that the hydraulic pressure increasing function of the second control B / B 32 is normal, then it is determined whether or not the pressure reducing function is normal. That is, the brake mechanism 6
9 to 9, the process proceeds from step S410 to step 410, where the second pressure increasing valve 38 is closed and the second pressure reducing valve 42 is opened so that the negative pressure chamber 32a and the variable pressure chamber 32b are closed. The generated differential pressure is extinguished. And step 42
The routine proceeds to 0 to check whether the actual brake pressure BPR has disappeared, that is, whether BPR = 0 holds.

If BPR = 0 holds, it can be determined that the hydraulic pressure reducing function of the second control B / B 32 is normal, and the second hydraulic pressure increasing function is checked together with the function check result.
The control B / B 32 can be judged to be completely normal. Therefore, when BPR = 0 is satisfied at step 420, the routine proceeds to step 430, where "0" is set to the flag XFB2 indicating the functional state of the second control B / B 32.

On the other hand, when it is determined in step 400 or step 420 that the hydraulic pressure increasing function or hydraulic pressure reducing function of the second control B / B 32 is abnormal,
In step 440, the flag XFB2 is set to "1" to indicate the failure of the second control B / B 32.

In the above steps 300 to 440, the brake initial check is completed. Thereafter, in step 450, the first to third shutoff valves 33, 34, 36 and the first pressure reducing valve 4
1 is opened and the first pressure increasing valve 37 is closed to set a state where intake negative pressure can be stored in the negative pressure chambers 31a and 32a and the variable pressure chambers 31b and 32b, and in the main routine shown in FIG.
Return to step 110.

For reference, a table showing the operation of each valve in the brake initial check routine is shown below.

[0064]

[Table 1]

In step 110 in FIG. 3, it is judged from the result of the brake initial check routine whether or not the brake is in failure, and if the brake is in failure, a failure processing loop described later is executed. move on. On the other hand, when it is determined that the brake is normal, the process proceeds to step 120, and it is determined whether the mode changeover switch 2 is in the physically disabled mode.

Here, when the mode changeover switch 2 does not represent the physically disabled mode, that is, when the driver is a healthy person, from the viewpoint of preventing sudden braking or the like due to an erroneous operation of the operating lever 5, as described above. The first and second control B / Bs 31, 32 need to be separated from the brake mechanisms 6-9. Therefore, if it is determined in step 120 that the person is not in the physically disabled mode, step 130
Then, the brake pressure reducing control is executed.

By the way, this brake pressure reducing control is performed by the first
The purpose is to create a situation in which the brake pressure is not increased depending on the second control B / Bs 31 and 32. Therefore,
In this embodiment, as shown in the flowchart of FIG. 5, the first and second pressure increasing valves 37 and 38 are closed, the first and second pressure reducing valves 41 and 42 are opened, and The first and second cutoff valves 33 and 34 are to be closed.

That is, in this case, the first control B / B3
In both No. 1 and the second control B / B 32, the negative pressure chambers 31a, 32a and the variable pressure chambers 31b, 32b are held in a conductive state, and the negative pressure chambers 31a, 32a are also maintained.
Also, the intake negative pressure is not supplied. Therefore, the hydraulic pressure is not increased in the master cylinders 31c and 32c, and the brake mechanisms 6 to 9 are always provided with the brake pedal 15
The brake pressure is supplied according to the pedaling force of.

On the other hand, if it is determined in step 120 that the mode changeover switch 2 is in the physically disabled mode, the process proceeds to step 140, and brake control is performed in accordance with the acceleration / deceleration instruction amount of the operating lever 5.

FIG. 6 is a flow chart of the brake control subroutine executed in step 140. Hereinafter, the operation of the brake booster device of the present embodiment will be described with reference to FIG. 6, but prior to that, the first and second control B / Bs 31, which are essential parts of the device of the present embodiment, will be described.
The role of each of the 32 will be described.

FIG. 7 shows how the internal pressure of the negative pressure chamber 31a changes when the hydraulic pressure is supplied to the brake mechanisms 6 to 9 using only the first control B / B 31, and the hydraulic pressure sensors 10 and 11 detect the internal pressure. The figure showing the mode of the change of the applied actual brake pressure is shown.

The curve indicated by the broken line in FIG. 7 is the third curve.
A state in which the shutoff valve 36 is closed, that is, a configuration similar to that of a conventional brake booster device having only one control B / B, and a curve indicated by a solid line in FIG. It shows a state in which the third cutoff valve 36 is opened and a negative pressure is also stored in the second control B / B 32.

As shown in FIG. 7, when the atmosphere is introduced into the variable pressure chamber 31b to start increasing the brake pressure at the time t ₁ , the negative pressure chamber 31c immediately after that regardless of opening / closing of the third shutoff valve 36. The internal pressure of the rises temporarily.

This is because the atmosphere flows into the transformation chamber 31b,
When the diaphragm separating the negative pressure chamber 31a and the variable pressure chamber 31b moves to the negative pressure chamber 31a side, the negative pressure chamber 31a
It is thought that this is due to the change in the volume of. That is, the negative pressure chamber 31 immediately after the atmosphere is introduced into the variable pressure chamber 31b.
This is because the negative pressure supply capability to the negative pressure chamber 31a is not secured to the extent that the volume change of a can be absorbed.

However, comparing the degrees of fluctuations in the internal pressure of the negative pressure chamber 31a, the rate of increase is obviously lower when the third shutoff valve 36 is opened. This is the third
In the state where the shutoff valve 36 is closed, it is necessary to absorb the volume change due to the transfer of the diaphragm or the like when the atmosphere is introduced, only by the volume of the negative pressure chamber 31a, while the third shutoff valve 36 is used.
Is open, the negative pressure chamber 31a, the second control B
This is because the total volume of the negative pressure chamber 32a and the variable pressure chamber 32b of / B can absorb the change.

By the way, such an increase in the internal pressure of the negative pressure chamber is caused by the pressure change chamber 31b and the negative pressure chamber 31a immediately after the introduction of the atmosphere.
Therefore, the differential pressure between and is reduced, and the responsiveness of the brake pressure to the driver's operation is deteriorated. Therefore, as shown in FIG. 7, when the third shutoff valve 36 is opened and when it is closed, the response is better when the valve is naturally open. .

That is, when the brake booster device having the above-mentioned structure is used to increase the brake pressure, the larger the volume in which the negative intake pressure of the internal combustion engine 35 can be stored in the brake booster device, the greater the driver's operation. The response of the brake pressure to the operation will be improved.

On the other hand, in a vehicle for a physically handicapped person, when the brake pressure supplied to the brake mechanisms 6 to 9 is increased by the brake booster device having the above-mentioned structure,
The brake booster device itself is required to have extremely high reliability, and a reliable fail-safe function in case of failure of the brake booster device is required. This is because, if an abnormality occurs in the brake booster device while the vehicle is traveling, it may be assumed that no braking force may work depending on the operation of the operation lever 5.

Therefore, in the apparatus of this embodiment, the second control B / B 32 is used as the first control B / B 3 instead of a simple vacuum tank as a means for expanding the space for storing the negative pressure.
1 is provided in parallel with the first control B / B 31, and when the first control B / B 31 fails, the second control B / B 32 can continue to control the brake pressure.

The operation of the electronically controlled brake system of this embodiment will be described in detail below with reference to the flow chart shown in FIG.

In the electronically controlled brake system of this embodiment, the brake pressure is increased by the first control B / B 31 or the second control B / B 32 as described above. Here, assuming that the first control B / B 31 is normal, the brake pressure is increased by the first control B / B 31, and the brake mechanisms 6 to 9 have the first negative pressure chamber 31b and the first negative pressure chamber 31b.
The hydraulic pressure corresponding to the differential pressure generated between the variable pressure chamber 31b is supplied.

In this case, in order to improve the responsiveness of the brake pressure, the second control B / B32 is replaced with the first control B / B3.
It is necessary to function as a vacuum tank that communicates with the first first negative pressure chamber 31b. Therefore, the second pressure increasing valve 38 is closed and the second and third shutoff valves 34, 36 and the pressure reducing valve 42 are opened to supply negative pressure to the negative pressure chamber 32a and the variable pressure chamber 32b while And the first negative pressure chamber 31b are communicated with each other.

By the way, the first and second pressure increasing valves 37 and 38 and the first and second pressure reducing valves 41 and 42 in the present embodiment open the conduction portions according to the pressure increasing signal or the pressure reducing signal supplied from the control ECU 1. This is a control valve that changes the area. That is, the device of the present embodiment opens the first pressure increasing valve 37 or the first pressure reducing valve 41 with an appropriate opening area, so that the amount of air flowing into the first pressure changing chamber 31b or the first pressure changing chamber 31b is increased.
By controlling the amount of air flowing out of the first variable pressure chamber 31b and the first negative pressure chamber 31b, an appropriate differential pressure is generated.

However, the amount of air flowing into the first variable pressure chamber 31b when the first pressure increasing valve 37 is opened and the amount of air flowing out of the first variable pressure chamber 31b when opening the first pressure reducing valve 41 are determined by It is not uniformly determined only by the opening area of the first pressure increasing valve 37 or the first pressure reducing valve 41. That is, even if the opening areas are the same, the first variable pressure chamber 31 when the first pressure increasing valve 37 is opened.
If the internal pressure of b is different, the amount of air flowing into the first variable pressure chamber 31b when the first pressure increasing valve 37 is opened changes depending on the internal pressure. Further, when the first pressure reducing valve 41 is opened in a state where the atmosphere is introduced into the first variable pressure chamber 31b, the first variable pressure chamber 31b is opened.
Similarly, the amount of air flowing out from is affected by the internal pressure of the first negative pressure chamber 31b when the valve is opened.

Therefore, in order to match the feeling instructed by the driver with the operation lever 5 and the braking force exerted by each of the brake mechanisms 6 to 9, regardless of the magnitude of the intake negative pressure of the internal combustion engine, When the first pressure increasing valve 37 is opened, the amount of air flowing into the first variable pressure chamber 31b is kept constant, and the first pressure reducing valve 4
1 is opened, the first variable pressure chamber 31b to the first negative pressure chamber 31
It is necessary to make the amount of air flowing out toward b constant.

Therefore, in this embodiment, the intake negative pressure generated in the intake pipe of the internal combustion engine is detected, and the first pressure increasing valve 37 and the first pressure reducing valve 41 are detected based on the detected intake negative pressure. The influence of the intake negative pressure is canceled by correcting the opening area when the valve is opened.

Therefore, when the brake control routine shown in FIG. 6 is started, first, at step 600, the engine speed NE is detected from the output signal of the speed sensor 4. Next, the routine proceeds to step 610, where the actual throttle opening THR is detected based on the output signal of the throttle opening sensor 24.

Here, it is known that the magnitude of the intake negative pressure E / GB has a larger value as the engine speed NE is larger and the throttle opening THR is smaller, as a function of NE and THR. You can ask. Therefore, in this embodiment, a map as shown in FIG.
It is stored in U1, and the intake negative pressure E / GB generated in the intake pipe of the internal combustion engine is obtained by referring to the map based on the detected NE and THR. (Step 620).

By the way, when braking the vehicle,
The lower the vehicle speed, the greater the shock caused by the braking. Further, generally, during low-speed traveling, delicate adjustment of the braking force is often required rather than the strong braking force. Therefore, in the system of the present embodiment, it is also necessary to make a correction according to the vehicle speed in order to make the driver's operation feeling correspond to the vehicle braking feeling.

Therefore, in this embodiment, when the intake negative pressure E / GB of the internal combustion engine is estimated in step 620, the process proceeds to step 630 and the vehicle speed V _W is calculated based on the output signal of the vehicle speed sensor 3.

In this way, the intake negative pressure E / GB and the vehicle speed V
After estimating the _W, then based on the E / GB and the vehicle speed V _W, we obtain the correction gain G _B and G _VW for introducing a predetermined amount of air into the first pressure changing chamber 31b.

As described above, the amount of air flowing into the first variable pressure chamber 31b depends on the opening area when the first pressure increasing valve 37 is opened and the pressure in the first variable pressure chamber 31b when the first pressure increasing valve 37 is opened, that is, the internal combustion engine. It is a function with the intake negative pressure E / GB of 35. Therefore, regardless of the magnitude of the intake negative pressure E / GB, the first variable pressure chamber 3
In order to introduce a certain amount of air into 1b, the intake negative pressure E /
The larger the GB, the smaller the opening area of the first pressure increasing valve 37 needs to be corrected.

Therefore, in this embodiment, the map shown in FIG. 9 is stored in the control ECU 1 in advance, and the correction gain G _{B is} obtained by referring to the map with the intake negative pressure E / GB estimated in step 620. Is calculated (step 640).

Regarding the relationship between the vehicle speed V _W and the braking force, as described above, the slower the vehicle speed V _W is, the first control B /
It is necessary to keep the hydraulic pressure increase rate by B31 low. That is, it is necessary to introduce a large amount of air into the first variable pressure chamber 31b during high speed traveling and to reduce a small amount of air to be introduced into the first variable pressure chamber 31b during low speed traveling.

Therefore, in this embodiment, for example, FIG.
0 and the vehicle speed V _W as shown in the correction gain G _VW relationship set in advance to the seeking correction gain G _VW by reference it in the vehicle speed V _W (step 650).

Next, at step 660, the required braking pressure TBPL corresponding to the braking force requested by the driver,
The difference ΔBP from the actual brake pressure detected by the hydraulic pressure sensors 10 and 11 is detected. Here, if ΔBP is a positive value, the driver is requesting a stronger braking force,
If ΔBP is not a positive value, the intention is to weaken the braking force.

By the way, the actual brake pressure BPR supplied to the brake mechanisms 6 to 9 is the pressure corresponding to the differential pressure generated between the first negative pressure chamber 31b and the first variable pressure chamber 31b as described above. Indicates. Therefore, the larger the actual brake pressure BPR, the larger the differential pressure between the first negative pressure chamber 31b and the first variable pressure chamber 31b, that is, the pressure in the first variable pressure chamber 31b should be close to the atmospheric pressure. On the other hand, when the first pressure increasing valve 37 is opened, the amount of air introduced into the first variable pressure chamber 31b per unit time becomes smaller as the pressure in the first variable pressure chamber 31b approaches atmospheric pressure. On the other hand, when the first pressure reducing valve 41 is opened, the amount of air flowing out from the first variable pressure chamber 31b toward the first negative pressure chamber 31b is such that the closer the pressure in the first variable pressure chamber 31b is to the atmospheric pressure, that is, The larger the actual brake pressure BPR, the larger the amount.

Therefore, it is necessary to correct the actual brake pressure BPR at each moment in order to correspond the actual change in the braking force to the operation feeling of the driver. That is,
When the driver is trying to increase the braking force, the larger the actual brake pressure BPR at that time is, the larger the opening area of the first pressure increasing valve 37 at the time of opening the valve is corrected, and the driver weakens the braking force. In this case, the larger the actual brake pressure BPR, the first pressure reducing valve 41 when the valve is opened.
It becomes necessary to correct the opening area of the.

Therefore, in the present embodiment, when ΔBP is detected in step 660, it is subsequently determined whether or not the value is a positive value (step 670). If ΔBP> 0, the correction gain G _BPU for increasing the actual brake pressure BPR is calculated (step 68).
0) and ΔBP ≦ 0, it is determined that the driver has the intention to weaken the braking force, and the correction gain G _BPD for reducing the actual brake pressure BPR is calculated (step 690).

In the present embodiment, the respective correction gains G _BPU and G _BPD are the actual brake pressure B as described above.
Paying attention to the value determined as a function of PR, the control ECU 1 stores in advance a map showing the relationship between G _BPU or G _BPD and BPR shown in FIGS. 11A and 11B,
Referring to this with the actual brake pressure BPR, G _BPU and G _{BP D}
Is to be asked.

After the correction gain G _B for the intake negative pressure of the internal combustion engine, the correction gain G _VW for the vehicle speed, and the correction gain G _BPU or G _BPD for the actual brake pressure BPR are calculated in this way, these correction gains are integrated. The total correction gain G _BRK is _calculated (step 700).

In this case, the above step 670 is executed.
If it is determined that ΔBP> 0, the total correction gain G _BRK = G _B * G _VW * G _BPU , and ΔBP ≦ 0.
If it is determined that the total correction gain G _BRK = G
It becomes _B * G _VW * G _BPD .

Then, in step 710, the total correction gain G _BRK is used to calculate the opening area TAF to be ensured in order to allow a desired amount of air to flow through the first pressure increasing valve 37 or the first pressure reducing valve 41. The opening area TAF of the first pressure-increasing valve 37 or the first pressure-reducing valve 41 has a difference between the braking pressure TBPR required by the driver and the actual braking pressure BPR in order to realize a braking force that matches the operation feeling of the driver. ,
That is, it is determined by integrating ΔBP calculated in step 660 and the total correction gain G _BRK .

By the way, the pressure increasing valve 37,
As shown in the characteristic diagram of FIG. 12, the pressure reducing valve 38 and the pressure reducing valves 41 and 42 have a characteristic of opening with an opening area TAF corresponding to the current I of the supplied pressure increasing or pressure reducing signal. Therefore,
When the opening area TAF is calculated in step 710, the process proceeds to step 720, and the current I to be supplied to realize the opening area TAF is calculated.

Then, for example, when the braking force is increased based on the operation of the operation lever 5 by the driver, the first pressure increasing valve 3
7 is supplied with the current I, and if it is desired to weaken the braking force, the current I is supplied with respect to the first pressure reducing valve 41 (step 730), and the current processing is ended.

As described above, in the apparatus of this embodiment, the first
When the control B / B is normal, the opening areas of the first pressure increasing valve 37 and the first pressure reducing valve 41 are appropriately adjusted, so that the braking force that always matches the driver's operation feeling can be secured. Also,
As described above, the second control B / B 32 is the first control B / B 32.
Since it functions as a / B31 vacuum tank, it has excellent responsiveness of brake pressure to operation,
As compared with the conventional brake booster device, it is possible to provide a braking force that better suits the driver's operation feeling.

When the brake control routine is completed, the process returns to the main routine again, and the brake failure is detected at step 150 in FIG. This is because even if it is normal in the initial check, it may break during traveling, and if the brake fails during traveling, some fail-safe must be performed to ensure safety.

The brake failure detection routine during traveling will be described below with reference to the flowchart shown in FIG. The apparatus of the present embodiment realizes the above-mentioned abnormality detecting means by executing this brake failure detection routine.

When this routine is activated, first, at step 800, the difference between the required brake pressure TBPR and the actual brake pressure BPR, that is, ΔBP, is calculated, and the calculated value is stored as the current brake pressure deviation BP _(t) . Next, the routine proceeds to step 810, where the brake pressure deviation B during the previous processing is B.
The difference between P _(t-1) and the current brake pressure deviation BP _(t) is calculated, and the value is stored as the brake pressure deviation differential value DBP _(t) .

Then, in step 820, the next processing is performed.
BP_(t-1)This time the brake pressure deviation BP_(t)Write on
After changing, proceed to step 830, and this time the brake pressure deviation
BP _(t)And a predetermined judgment value KFBP2 are compared. This
Here, the brake pressure deviation BP_{(t )}Is the judgment value KFBP2 or less
If (BP_(t)≤KFBP2) is the required brake
The actual brake pressure BPR follows the pressure TBPR.
That is, the first control B / B 31 is functioning normally.
You can determine that

On the other hand, the brake pressure deviation BP _(t) is equal to the judgment value K.
When it exceeds FBP2 (BP _{(t )} > KFBP2)
Means that the actual brake pressure BPR cannot follow the required brake pressure TBPR. Such a phenomenon is
This is a phenomenon that occurs when the first control B / B 31 fails and the brake pressure cannot be increased sufficiently, or when the driver requests sudden braking.

Therefore, in step 830, the BP is
If it is determined that _(t) > KFBP2 holds,
It is necessary to determine whether the cause is the failure of the first control B / B 31 or the sudden braking intended by the driver. Therefore, in step 840, the brake pressure deviation differential value DBP _(t) is compared with the predetermined determination value KFDBP1.

When DBP _(t) ≥ KFDBP1 is satisfied, the value of BP _(t) suddenly increases this time, that is, it is sudden that the brake pressure deviation BP _(t) exceeds the judgment value KFBP2. It can be determined that the first control B / B 31 is functioning normally by the braking request.

On the other hand, when DBP _(t) <KFDBP1 is satisfied, that is, when the actual brake pressure BPR cannot keep up with the required brake pressure TBPR since the previous processing, that state continues for a long time. It becomes necessary to confirm whether or not If the normal state is restored within a short period of time, the hydraulic system delay during sudden braking is the cause, and the first control B / B
If 31 can be determined to be normal, or if the state is maintained for a predetermined period, the first control B /
This is because it is necessary to determine that the failure is in B31.

Therefore, in step 840, the DB
When it is determined that P _(t) <KFBP1 is satisfied, the timer CFB is incremented in step 850, and it is determined in step 860 whether the timer CFB has reached a predetermined value KFBT. And C
When FB ≧ KFBT is established, B / B for the first control
When it is determined that No. 31 is out of order, in step 870, the flag XFB1 indicating the first control B / B 31 failure is set to "1", and the processing of this time is ended.

Also, in step 860, the CFB
If it is determined that the KFBT has not reached KFBT yet, the above steps 830 and 8 are repeated each time this processing is executed.
At 40, it is determined whether or not the abnormal state continues, and the above process is repeatedly executed as long as the abnormal state continues. Then, when CFB ≧ KFBT is satisfied, the routine proceeds to step 870, where “1” is set to the flag XFB1.

On the other hand, in step 830, the BP
_{If (t)} ≤ KFBP2 or DBP _(t) ≥ KFDBP1 in step 840, the first control B / B 31 can be determined to be normal as described above, and therefore the flag XFB1 is determined in step 880. Also, "0" is set to both the timer CFT and the processing of this time is ended.

When the brake failure is detected in this way, the process returns to the main routine and step 160 is executed. In this step 160, it is determined whether or not the brake is out of order by looking at the value of the flag XFB1 set in the above subroutine.

If it is determined that the brake is not in failure, the routine proceeds to step 170 to continue normal operation, and throttle control is performed this time. Hereinafter, the throttle control in the apparatus of this embodiment will be described with reference to the flowchart of the throttle control subroutine shown in FIG.

In the apparatus of this embodiment, the feedback system is constructed by using the opening sensor 24 for detecting the actual opening of the throttle valve 13, and the proportional-integral-derivative control (PID
The DC motor 21 is driven by the control.

When the throttle control routine is activated, first, at step 900, the throttle opening instruction amount TTH by the operating lever 5 is detected. Then step 910
Then, based on the actual throttle opening THR detected by the opening sensor 24, the throttle deviation ΔTTH = TTH
-THR (= TTH _(t) ) is calculated.

Subsequently, the routine proceeds to step 920, where the throttle deviation TTH _{(t) at} this time and the throttle deviation at the time of the previous processing are used as the basis for calculating the component constituted by the differential control in the opening instruction signal supplied to the DC motor 21. TT
The differential amount DTTH of the throttle deviation is calculated by taking the difference from H _(t-1) (step 920).

Further, in step 930, the throttle deviation TTH _(t) of this time is added to the integrated value of the throttle deviation up to the previous time, as a basis for calculating the component constituted by the integration control in the opening instruction signal, ΔTTH integration amount ∫
Calculate ΔTTH.

Then, the process proceeds to step 940 and preset.
Proportional gain G_P, Integral gain G _I, Differential gain G_D
The basic control amount TTHI is calculated using the following equation.

TTHI = G_P・ ΔTTH + G_I・ ∫ΔTTH + G_DWhen the DTTH basic control amount TTHI can be calculated, go to step 950.
Battery voltage V _BCorrection for fluctuations in. car
The voltage of the batteries installed on both sides depends on the operating conditions of the vehicle.
Although it fluctuates more greatly, the opening of the throttle valve 13
Is required to be controlled with extremely high accuracy.
It should be noted that the control ECU 1 of the apparatus of the present embodiment uses the battery voltage V_B
Correction factor K for_VBIs prepared in advance as a map
(See FIG. 15), the map shows the battery voltage V_BReferenced by
The correction coefficient K required by this_VBTo calculate.

Then, the actual control amount is calculated by multiplying the basic control amount TTHI calculated in step 940 by this correction coefficient K _VB, and the value is stored as TTHI (step 960).

After the control amount TTHI to be supplied to the DC motor 21 is calculated in this way, a duty ratio for realizing the control amount TTHI is calculated in step 970. Then, the signal of the duty ratio calculated in step 980 is output to the DC motor drive circuit, and the processing of this time is ended.

As described above, in the apparatus of this embodiment, the opening degree of the throttle valve 13 is executed by PID control. Therefore, the desired throttle opening degree can be secured with high accuracy and good response to the driver's instruction.

Thus, the processing of step 170 in the main routine shown in FIG. 3 is completed. After that, unless the disabled mode is released or an abnormality occurs in the first control B / B 31, step 12 in the main routine is performed.
0 to 170 are repeatedly executed, and the vehicle exerts the driving force and the braking force as the driver operates the operation lever 5.

By the way, if it is determined in step 110 in FIG. 3 that the brake has already failed in the initial stage, the process proceeds to step 180, and after the abnormality lamp is turned on to notify the driver of the occurrence of abnormality. In step 190, it is determined whether or not the mode selected by the mode changeover switch is the physically disabled mode.

Here, when the healthy person mode is selected, the routine proceeds to step 200, where the brake pressure reducing control shown in FIG. 5 is executed, and the first and second control B / B 31, 3 are performed.
2 is substantially disconnected from the brake system. The failure is due to the first control B / B31 or the second control B / B, which is based on the premise of the physically disabled mode.
This is because there is no obstacle to running if the normal person mode is selected in B32.

Then, unless it is determined in step 190 that the disabled mode is selected, steps 180 to 200 are repeatedly executed, and normal traveling is ensured although the abnormal lamp is lit.

On the other hand, when the physically disabled mode is selected in step 190, the process proceeds to step 210, and the failure process 1 is executed. The failure processing 1 routine will be described below with reference to the flowchart shown in FIG.

When the failure processing 1 routine is started, first, at step 1010, the first and second pressure increasing valves 37, 3 are made.
8 and the first and second cutoff valves 33, 34 are opened, and the first and second pressure reducing valves 41, 42 and the third cutoff valve 36 are closed. Therefore, the first control B / B 31 and the second control B / B 32 increase the brake pressure independently of each other. Therefore, even if one of the control B / Bs 31 and 32 is in a state where pressure cannot be increased, the increased brake pressure is supplied to the brake mechanism and the braking force acts on the vehicle. Becomes

Then, in step 1020, the electromagnetic clutch 22 that connects the throttle valve 13 and the DC motor 21 is disconnected. As a result, the throttle valve 13 does not operate depending on the operation of the operation lever 5, and the throttle valve 13 is substantially fixed at the fully closed position.

Therefore, when the failure processing 1 routine is executed, the vehicle is in the idling state and cannot move while stopped, and the failed control B / B 31, 32.
Does not run in a faulty state. Even in such a state, when the healthy person mode is selected, normal traveling is secured as described above, and it is possible to drive to a repair shop or the like by itself.

On the other hand, when a brake failure occurs while the vehicle is traveling, unlike the initial failure described above, processing is required that can safely stop the traveling vehicle.
In the device of the present embodiment, as described above, the brake failure while the vehicle is traveling is detected in step 160.

Step 16 which is the main part of this embodiment will be described below.
A process when a failure is detected at 0 will be described.

When a brake failure, that is, a failure of the first control B / B 31 is detected at step 160,
The abnormal lamp is turned on as shown in FIG. 3 (step 220).
After that, the routine proceeds to step 230, where the failure processing 2 for realizing the abnormal time control means in the apparatus of this embodiment is executed. The failure processing 2 routine will be described below with reference to the flowchart shown in FIG.

When the failure processing 2 routine is activated, first, at step 1110, the first pressure increasing valve 37 and the first shutoff valve 33 are closed, and the first pressure reducing valve 41 and the second shutoff valve 34 are opened. By this processing, the first control B / B3 is substantially
1 is in a state of being disconnected from the brake system of the present embodiment, and is in a state in which brake pressure control by the second control B / B 32 is possible.

In step 1120, the electromagnetic clutch 22 is disengaged and the throttle valve 1 is opened to ensure that the vehicle is not accelerated until it stops safely.
The operation of 3 is disabled. And step 11
At 30, the brake control shown in FIG. 6 is executed for the second control B / B 32.

Therefore, in the vehicle equipped with the brake booster device according to the present embodiment, the failed first control B / B is used.
It is possible to stop safely by the brake pressure boosted by the second control B / B 32 without sudden braking due to the abnormal operation of 31.

As shown in FIG. 3, when a failure is detected in step 160, the abnormal lamp lighting processing (step 220) and the failure processing 2 routine (step 2) are performed thereafter.
30) and are repeatedly executed, and this processing is continued unless the ignition switch of the internal combustion engine is turned off.

For reference, the first control B / B is as follows.
The table which shows operation | movement of each valve of 31 at the time of normal and abnormal.

[0145]

[Table 2]

As described above, according to the apparatus of this embodiment,
Second if the first control B / B 31 is functioning normally
When the control B / B 32 functions as a vacuum tank, good responsiveness of the brake pressure to the operation can be secured, and when the first control B / B 31 fails,
A reliable fail-safe process is realized by the second control B / B 32, and the braking force can be reliably ensured even in the event of an abnormality.

Therefore, there is no fear that the brake will not work at all while the vehicle is running, and it is possible to ensure sufficient safety as a vehicle for the physically handicapped.

In the above embodiment, the control B / B is used.
However, the present invention is not limited to this, and may be any configuration in which a plurality of control B / Bs are combined in parallel and used.

[0149]

As described above, according to the present invention, since the first brake booster and the second brake booster are provided so that their negative pressure chambers can communicate with each other, either brake booster is provided. When using to increase the brake pressure,
The other brake booster can be used as a vacuum tank. Therefore, the pressure fluctuation of the negative pressure chamber immediately after the start of increasing the brake pressure is suppressed, and the responsiveness of the brake pressure to the driver's operation can be improved as compared with the conventional brake booster device.

Further, since the two brake boosters are provided in parallel, if one brake booster fails, the other brake booster can increase the brake pressure, and while the vehicle is traveling. There is no worry that the braking force will not be obtained. As described above, the brake booster device according to the present embodiment has a feature that it is possible to ensure remarkably high reliability as compared with the conventional device.

[Brief description of drawings]

FIG. 1 is a principle view of a brake booster device according to the present invention.

FIG. 2 is an overall view showing a configuration of an embodiment of a brake booster device according to the present invention.

FIG. 3 is a flowchart of a main routine executed by a control ECU of the device of this embodiment.

FIG. 4 is a flowchart of a brake initial check subroutine executed by a control ECU of the present embodiment device.

FIG. 5 is a flowchart of a brake pressure-reducing control subroutine executed by a control ECU of the present embodiment device.

FIG. 6 is a flowchart of a brake control subroutine executed by a control ECU of the present embodiment device.

FIG. 7 is a diagram showing changes in the internal pressure of the negative pressure chamber of the control B / B and the brake pressure increased by the control B / B of the apparatus of this embodiment.

FIG. 8 is a characteristic diagram showing a relationship between a throttle opening THR and an engine speed NE and an intake negative pressure E / GB of an internal combustion engine equipped with the device of the present embodiment.

FIG. 9 is a map for obtaining a correction gain G _B for the intake negative pressure E / GB in the present embodiment device.

FIG. 10 is a map for _obtaining a correction gain G _VW with respect to the vehicle speed V _{W in the} apparatus of this embodiment.

FIG. 11 is a correction gain G _BPU during pressure increase and a correction gain G during pressure reduction with respect to the actual brake pressure BPR in the device of this embodiment.
_This is a map for _{obtaining BPD} .

FIG. 12 is an opening area TAF and a current I of a flow rate instruction signal when the atmosphere introduction valve and the negative pressure introduction valve of the device of this embodiment are opened.
It is a characteristic view showing the relationship with.

FIG. 13 is a flowchart of a brake failure detection subroutine executed by the control ECU of the present embodiment device.

FIG. 14 is a flowchart of a throttle control subroutine executed by a control ECU of the present embodiment device.

FIG. 15 is a map showing a relationship between a battery voltage used for throttle control and a correction value in the device of the present embodiment.

FIG. 16 is a flowchart of a failure processing 1 subroutine executed by the control ECU of the device of this embodiment.

FIG. 17 is a flowchart of a failure processing 2 subroutine executed by the control ECU of the present embodiment device.

[Explanation of symbols]

 M1 First brake booster M1a, M2a Negative pressure chamber M1b, M2b Transformation chamber M1c, M2c Master cylinder M2 Second master cylinder M3, 6-9 Brake mechanism M4 Control valve M5 Communication passage M6 Abnormality detection means M7 Abnormality control means 1 Control ECU 2 Mode Changeover Switch 5 Operating Lever 10, 11 Oil Pressure Sensor 31 First Control Brake Booster 31a, 32a Negative Pressure Chamber 31b, 32b Variable Pressure Chamber 31c, 32c Master Cylinder 32 Second Control Brake Booster 33 First Cutoff Valve 34 2nd cutoff valve 36 3rd cutoff valve 37 1st pressure increasing valve 38 2nd pressure increasing valve 41 1st pressure reducing valve 42 2nd pressure reducing valve

Claims (1)

[Claims] 1. A variable pressure chamber capable of storing a negative pressure supplied from a negative pressure supply source and setting an internal pressure to a predetermined negative pressure by introducing air, and a negative pressure supplied from the negative pressure supply source. A brake consisting of a negative pressure chamber that can store the internal pressure of a negative pressure chamber to store the negative pressure in the negative pressure chamber, and a master cylinder that converts the thrust corresponding to the pressure difference between the internal pressure of the variable pressure chamber and the negative pressure chamber into the hydraulic pressure of the brake mechanism A brake booster device for increasing a brake operating force by a driver using a booster, comprising: a first brake booster, a second brake booster, a negative pressure chamber of the first brake booster, and the second brake. A control valve that is provided in a communication passage that communicates with the negative pressure chamber of the booster and that controls conduction between the two, and an abnormality detection that detects an abnormality of one of the first brake booster and the second brake booster. And an abnormality of the one brake booster is detected by the abnormality detecting means, the control valve is closed to shut off the communication passage and supply hydraulic pressure from the one brake booster to the brake mechanism. A brake booster device comprising: an abnormal-time control means for stopping the brake.