JPH08295231A - Brake booster system - Google Patents

Abstract

PURPOSE: To enable brake pressure to be increased even when a pressure source has failed and to ensure that an automobile is stopped with a smaller pedal force during sudden braking. CONSTITUTION: Should a negative pressure source 4 fail, a negative-pressure failure detection signal from a pressure switch 15 is input to an ECU 16. When a hydraulic pressure of a master cylinder 5 is generated by the operation of a brake pedal 2, a brake operation detection signal from a pressure pickup 9 is input to the ECU 16. The ECU 16 switches a shutoff valve 10 to a shutoff position II according to the two signals and drives a pump 12. Since a passage 8 is shut off and the pump 12 supplies a brake fluid in a reservoir 6 to a brake cylinder 7, the brake cylinder 7 generates a great brake force. In this case, a current supplied to the pump 12 is controlled in accordance with the hydraulic pressure of the master cylinder 5, thus ensuring that the brake force boosted to match the pedal force is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake booster system for generating a large braking force by a fluid pressure, and in particular, it can generate a sufficiently large braking force even when the fluid pressure of a pressure source is lost. It is related to the brake booster system.

[0002]

2. Description of the Related Art For example, in an automobile, when a large braking force that cannot be obtained only by the driver's brake pedal force is required, or when the driver's brake pedal force is reduced, vacuum, compressed air or A brake booster system is used in which a large braking force can be obtained by using a pressure such as a hydraulic pressure.

Further, in such a brake booster system, if the fluid pressure of the pressure source fails, there is a possibility that a sufficient braking force cannot be obtained. For this reason, when the pressure source fails, the operating force of the brake operating member must be made much larger than in the normal case. Therefore, Japanese Patent Publication No. 6-29011 proposes a brake boosting system capable of obtaining a relatively large braking force even with a normal brake operating force when the pressure source fails.

FIG. 10 is a diagram showing the brake booster system disclosed in this publication. In the figure, 131 is a brake booster system, 132 is a brake pedal, 133 is a hydraulic booster, 134 is a master cylinder, 135 is a wheel cylinder, 136 is a pump, 137 is an accumulator, 138 is a pressure booster, 139 is a pressure boosting piston, 140 is an on-off valve.

As shown in FIG. 10, a pressure boosting piston 139.
Is a stepped piston, and the master cylinder pressure acts on the pressure receiving surface on the left side of the large diameter portion, and the pressure booster 133 has a hydraulic pressure chamber (not shown) on the pressure receiving surface on the right side. Hydraulic pressure is applied.

When the brake is not operated, the booster piston 13
9 is at the position shown, and the open / close valve 140 is open. When the brake pedal 132 is depressed when the pressure source is normal, the control valve of the hydraulic booster 133 is switched, the hydraulic fluid flows into the hydraulic pressure chamber, and the power piston (not shown)
Moves forward. As a result, the master cylinder 134 generates a brake fluid pressure, which is supplied to the pressure booster 138 and further supplied to the wheel cylinder 135 through the open / close valve 140 which is opened to operate the wheel cylinder 135. The brake works. At this time, the booster 138
The brake hydraulic pressure of the master cylinder 134 acts on the left large diameter portion pressure receiving surface and the right small diameter portion pressure receiving surface of the pressure boosting piston 139, and the hydraulic booster 13 is applied to the right side step portion pressure receiving surface.
Since the hydraulic pressure in the hydraulic pressure chamber 3 acts, the booster piston 1
39 does not move. Therefore, the on-off valve 140 is kept open, and the brake fluid pressure of the master cylinder 134 is supplied to the wheel cylinder 135 as it is without being boosted by the booster 138.

When the pressure source fails, the brake pedal 13
Even if you depress 2, the hydraulic fluid does not flow into the hydraulic chamber,
The power piston does not advance depending on the hydraulic fluid. By further depressing the brake pedal 132, the power piston moves forward by the pedal effort. As a result, the master cylinder 134 generates brake fluid pressure, and this brake fluid pressure is supplied to the pressure booster 138, and the open / close valve 14 that is further opened.
It is supplied to the wheel cylinder 135 through 0. At this time, the master cylinder 134 is provided on the left large diameter portion pressure receiving surface and the right small diameter portion pressure receiving surface of the pressure boosting piston 139 of the pressure booster 138.
However, since the hydraulic pressure of the hydraulic pressure chamber of the hydraulic booster 133 does not act on the pressure receiving surface on the right side step,
The boost piston 139 moves to the right, and the on-off valve 140 closes. Therefore, the master cylinder 134 and the wheel cylinder 135 are cut off. After the on-off valve 140 is closed, the brake fluid pressure in the master cylinder 134 is increased by the pressure increaser 138 by the pressure increase ratio {(large diameter portion pressure receiving area) / (small diameter portion pressure receiving area)}, and this pressure increased brake is applied. Hydraulic pressure is supplied to the wheel cylinder 135. As a result, when the pressure source fails, a relatively large brake fluid pressure can be generated even with a relatively small pedal effort, in other words, the pedal effort can be reduced.

[0008]

By the way, in such a brake booster system 131, since the brake fluid pressure of the master cylinder 134 is increased by the pressure increasing piston 139, in order to obtain a large pressure increase ratio, It is necessary to increase the diameter of the large diameter portion of the pressure piston 139. However, if the diameter of the large diameter portion of the booster piston 139 is increased, the amount of brake fluid sent from the master cylinder 134 must also be increased. For this reason, the pedal stroke of the brake pedal 132 becomes large and the pedal feel becomes poor. Therefore, the diameter of the large diameter portion of the pressure boosting piston 139 cannot be increased so much, and the pressure boosting ratio of the pressure booster 138 is limited. For this reason, in the brake booster system 131, when the pressure source fails, the brake fluid pressure cannot be greatly increased to the same level as the brake fluid pressure when the pressure source is normal.

In addition, since the brake fluid pressure cannot be greatly increased when the pressure source fails, the pressure source is used especially when a heavy vehicle is stopped or when the vehicle is stopped by sudden braking. There is a problem that not only a large pedal effort is required in the event of a failure, but it is difficult to stop the vehicle for a short braking distance.

The present invention has been made in view of the above circumstances, and an object thereof is to greatly increase the brake pressure even when the pressure source fails, almost in the same manner as when the pressure source is normal. It is possible to provide a brake booster system capable of reliably stopping a heavy vehicle or stopping at a sudden brake with a smaller pedal effort and a short braking distance.

[0011]

In order to solve the above-mentioned problems, the invention of claim 1 is a brake pedal, a pressure source for generating fluid pressure, and the pressure source operated by depression of the brake pedal. The fluid pressure booster that boosts and outputs the pedal effort of the brake pedal by the fluid pressure, the master cylinder that is actuated by the output of the fluid pressure booster to generate brake fluid pressure, and the master cylinder In a brake booster system that includes a reservoir that stores the brake fluid that is supplied and discharged, and a brake cylinder that is supplied with the brake fluid pressure to generate a braking force, and that generates a braking force that boosts the pedaling force of the brake pedal. A pressure detecting means for detecting that the fluid pressure of the pressure source has dropped below a predetermined pressure and outputting a pressure source failure detection signal; The brake operation detecting means for detecting a brake operation due to the depression of the lever and outputting a brake operation detection signal, and the first passage communicating the master cylinder and the brake cylinder are provided with a communication position and a cutoff position. Normally open shut-off valve consisting of a solenoid valve,
A second passage that connects the reservoir to the first passage between the shutoff valve and the brake cylinder; and a second passage that is provided in the second passage and serves to store the brake fluid in the reservoir between the shutoff valve and the brake cylinder. Of the brake fluid that is provided in the second passage on the discharge side of the pump and that is directed from the reservoir to the first passage between the shutoff valve and the brake cylinder. When the check valve that allows only the flow, the pressure source failure detection signal from the pressure detection means, and the brake operation detection signal from the brake operation detection means are input, the shutoff valve is set to the shutoff position. When the brake operation is performed in a pressure source failure state, the brake operation is performed by the discharge pressure from the pump. It is characterized in that.

According to a second aspect of the present invention, the brake operation detection signal from the brake operation detection means is a signal corresponding to the pedal effort of the brake pedal, and the electronic control unit is configured to operate in accordance with the pedal effort of the brake pedal. It is characterized by controlling the supply current to the pump.

Further, in the invention of claim 3, the first passage between the second passage and the shutoff valve and the brake cylinder is provided.
A third passage connecting between the passages bypassing the pump and the check valve, and a normally-closed on-off valve formed of a solenoid valve provided in the third passage and provided with a shutoff position and a communication position. A second pressure detecting means for detecting a fluid pressure in the first passage between the shutoff valve and the brake cylinder and outputting a pressure signal, wherein the electronic control unit outputs the pressure signal from the brake operation detecting means. By controlling the supply current to the pump and the opening / closing of the on-off valve based on the brake operation detection signal and the pressure signal from the second pressure detection means, respectively, a brake for brake operation by the discharge pressure from the pump The force is controlled according to the depression force of the brake pedal.

Further, the invention according to claim 4 is a normally-closed on-off valve comprising an electromagnetic valve disposed in the second passage between the reservoir and the pump, the solenoid valve having a shut-off position and a communication position. A proportional control valve for controlling and outputting the discharge pressure from the pump, wherein the electronic control unit has the pressure source failure detection signal from the pressure detection means and the brake operation detection signal from the brake operation detection means. The opening and closing valve is set to the communication position based on the above, and the brake current is supplied to the pump and the proportional control valve is controlled based on the brake operation detection signal. The braking force is controlled according to the depression force of the brake pedal.

Further, the invention according to claim 5 is a normally-closed on-off valve comprising an electromagnetic valve disposed in the second passage between the reservoir and the pump, the solenoid valve having a shut-off position and a communication position. The third passage branched from the second passage between the on-off valve and the pump, and the brake cylinder from the confluence of the first passage and the second passage between the shutoff valve and the brake cylinder. And a second position that is disposed in the first passage on the side and connects the brake cylinder to the first passage between the shut-off valve and the brake cylinder, and a second position that connects the brake cylinder to the third passage. And a switching valve that is normally set to the first position, and a first passage between the merging position and the switching valve that is provided with a communication position and a shut-off position, and the brake cylinder. A normally open second cutoff valve which is set to the cutoff position when the brake fluid pressure is higher than the pressure at the confluence position by a predetermined pressure, and the electronic control unit detects the pressure source failure from the pressure detection means. The on-off valve is set to a communication position based on the signal and the brake operation detection signal from the brake operation detection means, and the supply current to the pump and the switching valve are respectively set based on the brake operation detection signal. It is characterized in that the braking force of the brake operation by the discharge pressure from the pump is controlled according to the depression force of the brake pedal by controlling and opening / closing the second cutoff valve by the brake fluid pressure of the brake cylinder. There is.

Further, the invention of claim 6 is operated by a brake pedal, a pressure source for generating a fluid pressure, and the depression of the brake pedal. The fluid pressure of the pressure source boosts the depression force of the brake pedal. Fluid pressure booster that outputs the pressure, a master cylinder that is activated by the output of this fluid pressure booster to generate brake fluid pressure, a reservoir that stores brake fluid that is supplied to and discharged from this master cylinder, and this brake. In a brake booster system that includes a brake cylinder that is supplied with hydraulic pressure and that generates a braking force, and that generates a braking force that boosts the pedaling force of the brake pedal, the fluid pressure of the pressure source is below a predetermined pressure. A pressure detecting means for detecting that a pressure source failure detection signal is output, and a first for connecting the master cylinder and the brake cylinder. Disposed in the passage, a normally open shutoff valve communicating position and a blocking position an electromagnetic valve provided,
A second passage that connects the reservoir to the first passage between the shutoff valve and the brake cylinder; and a second passage that is provided in the second passage and serves to store the brake fluid in the reservoir between the shutoff valve and the brake cylinder. Of the brake fluid that is provided in the second passage on the discharge side of the pump and that is directed from the reservoir to the first passage between the shutoff valve and the brake cylinder. A check valve that allows only a flow, and a brake fluid pressure of the master cylinder, which is provided at least in the second passage on the discharge side of the pump, is introduced as pilot pressure, and the pump pressure of the pump is changed according to the magnitude of the pilot pressure. When the pressure adjusting valve for adjusting the discharge pressure and the pressure source failure detection signal from the pressure detecting means are input, the shutoff valve is set to the shutoff position and the shutoff valve is set to the shutoff position. An electronic control unit for driving and controlling the pump, and when the brake operation is performed in a pressure source failure state, the discharge pressure from the pump is adjusted according to the magnitude of the brake hydraulic pressure of the master cylinder. The feature is that the brake is operated by adjusting the discharge pressure.

Further, the invention according to claim 7 is a normally-closed on-off valve comprising an electromagnetic valve disposed in the second passage between the reservoir and the pump, the solenoid valve having a shut-off position and a communication position. The third passage branched from the second passage between the on-off valve and the pump, and the brake cylinder from the confluence of the first passage and the second passage between the shutoff valve and the brake cylinder. And a second position that is disposed in the first passage on the side and connects the brake cylinder to the first passage between the shut-off valve and the brake cylinder, and a second position that connects the brake cylinder to the third passage. Is provided in the first passage between the merging position and the switching valve, and a communication position and a shut-off position are provided. With said bu A normally open second shutoff valve which is set to the shutoff position when the brake fluid pressure of the brake cylinder is higher than the pressure at the confluence position by a predetermined pressure; and the electronic control unit detects the pressure source failure from the pressure sensing means. Based on the signal, the on-off valve is set to the communication position and the switching valve is set to the second position, and the pump is drive-controlled. The discharge pressure of the pump is adjusted according to the magnitude of the brake fluid pressure of the master cylinder to perform the brake operation.

Further, the invention of claim 8 is characterized in that the fluid pressure booster is a negative pressure booster. Further, the invention of claim 9 is characterized in that the fluid pressure booster is a hydraulic booster.

Further, the invention of claim 10 stores a hydraulic fluid supplied to and discharged from the hydraulic booster and a first reservoir tank and a second reservoir tank connected to each other, and the hydraulic booster. Spaced apart from the first
A normal brake booster pump for supplying hydraulic fluid from a reservoir tank to the hydraulic booster, and the first reservoir tank is arranged in the vicinity of the normal brake booster pump, The second reservoir tank is arranged in the vicinity of the hydraulic booster.

[0020]

In the brake booster system according to the present invention having the above-described structure, the pressure source failure detection signal output by the pressure detecting means when the fluid pressure of the pressure source is equal to or lower than the predetermined pressure, and the brake. The electronic control unit sets the shutoff valve to the shutoff position and drives the pump based on the brake manipulation detection signal output from the brake manipulation detection means when the pedal is depressed. By driving this pump, the brake fluid in the reservoir of the master cylinder is supplied to the brake cylinder through the second passage. When the loss stroke of the brake cylinder disappears, the pump generates the discharge pressure, and the discharge pressure causes the brake cylinder to generate a large braking force. At this time, since the shutoff valve is in the shutoff position and shuts off the first passage, the discharge pressure of the pump does not leak toward the master cylinder and the pressure is not lost. Therefore, a braking force that greatly boosts the pedal effort can be reliably obtained.

According to the second aspect of the invention, the pump is controlled by the electronic control unit in accordance with the depression force of the brake pedal. As a result, the pump discharge pressure is controlled according to the depression force of the brake pedal, so that the braking force generated by the brake cylinder corresponds to the depression force of the brake pedal.

Further, in the third aspect of the invention, the electronic control unit causes the current supplied to the pump and the opening / closing of the opening / closing valve based on the brake operation detection signal from the brake operation detection means and the pressure signal from the second pressure detection means. Respectively, the braking force is more surely responded to by the depression force of the brake pedal.

Further, in the invention of claim 4, the electronic control unit controls the supply current to the pump and the proportional control valve based on the brake operation detection signal from the brake operation detection means and the pressure signal from the second pressure detection means. Since they are controlled respectively, the braking force can be more surely responded to by the depression force of the brake pedal.

Further, in the fifth aspect of the invention, the electronic control unit controls the supply current to the pump and the switching valve based on the brake operation detection signal to control the brake fluid pressure of the brake cylinder and the brake cylinder. Since the brake fluid pressure is controlled by itself, the braking force more reliably corresponds to the pedaling force of the brake pedal.

Further, in the sixth aspect of the invention, the electronic control unit sets the shutoff valve to the shutoff position based on the pressure source failure detection signal output by the pressure detection means when the fluid pressure of the pressure source is equal to or lower than the predetermined pressure. At the same time, the pump is driven. By driving this pump, the brake fluid in the reservoir of the master cylinder is supplied to the brake cylinder through the second passage. When the loss stroke of the brake cylinder disappears, the pump generates the discharge pressure. This discharge pressure is adjusted by the pressure adjusting valve according to the brake fluid pressure of the master cylinder, and the adjusted discharge pressure causes the brake cylinder to generate a large braking force. At this time, since the shutoff valve is in the shutoff position and shuts off the first passage, the discharge pressure of the pump does not leak toward the master cylinder and the pressure is not lost. Therefore, the braking force greatly boosted according to the pedal effort can be reliably obtained.

Further, in the invention of claim 7, the electronic control device controls the supply current to the pump based on the brake operation detection signal to control the pump discharge pressure, and the pump discharge pressure is controlled by the pressure control valve. The adjusted discharge pressure is supplied to the brake cylinder, which is adjusted according to the brake fluid pressure in the cylinder. Then, the electronic control unit further controls the switching valve to control the brake fluid pressure in the brake cylinder, and also controls the brake fluid pressure in the brake cylinder based on itself, so that the braking force depends on the depression force of the brake pedal. It will be more reliable.

Furthermore, in the present invention of claim 8, the present invention is applied to a brake booster system using a negative pressure booster. Further, in the invention of claim 9, the present invention is applied to a brake booster system using a hydraulic booster.

Further, in the invention of claim 10, the normal brake booster pump is disposed far away from the hydraulic booster, and the first reservoir tank is disposed at a position lower than the hydraulic booster. However, the second reservoir tank can be arranged at a higher position in the vicinity of the hydraulic booster. Therefore, the low pressure chamber of the hydraulic booster can be reliably filled with the hydraulic fluid from the second reservoir tank, and the rusting of parts in the hydraulic booster can be reliably prevented. .

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a first embodiment of a brake booster system according to the present invention.

As shown in FIG. 1, the brake booster system 1 of the first embodiment has a brake pedal 2 and a negative pressure booster which is controlled by the brake pedal 2 and constitutes a fluid pressure booster of the present invention. Device 3, negative pressure source 4 that generates a negative pressure that is a fluid pressure supplied to the negative pressure booster 3 and constitutes a pressure source of the present invention, and two brake systems operated by the negative pressure booster 3. Tandem master cylinder 5, a reservoir 6 for storing brake fluid supplied to the tandem master cylinder 5, a brake cylinder 7 to which brake fluid from the master cylinder 5 is supplied, and one of the master cylinder 5 and the brake cylinder 7. Of the brake system of the present invention, which is arranged in the passage 8 of the brake system and detects a brake fluid pressure equal to or higher than a predetermined pressure in the passage 8 and outputs a brake operation detection signal. (Corresponding to a brake operation detecting means), a normally open shut-off valve 10 including a solenoid valve provided in a passage 8 between the pressure pickup 9 and the brake cylinder 7 and provided with a communication position I and a shut-off position II. A passage 11 connected to the reservoir 6 and a passage 8 between the shutoff valve 10 and the brake cylinder 7, and a pump 12 provided in the passage 11.
And a pair of check valves 13 and 14 provided on the suction side and the discharge side of this pump respectively, which allow only the flow of the brake fluid in the direction from the reservoir 6 to the passage 8, and the negative pressure of the negative pressure source 4. Pressure switch 15 (corresponding to the pressure detecting means of the present invention) which is activated when the value becomes equal to or less than a predetermined value and outputs a negative pressure failure detecting signal (corresponding to the pressure source failure detecting signal of the present invention).
, A pressure pickup 9, a shutoff valve 10, a pump 12 and a pressure switch 15 are respectively connected, and the shutoff valve 10 and the pump are pumped based on a brake operation detection signal from the pressure pickup 9 and a negative pressure failure detection signal from the pressure switch 15. An electronic control device (hereinafter, EC
16) and the ECU 16 connected to the ECU 16
It is provided with an alarm device 17 such as an alarm lamp and an alarm buzzer for issuing an alarm by an alarm signal from.

The brake pedal 2, the negative pressure booster 3, the negative pressure source 4, the master cylinder 5, the reservoir 6, the brake cylinder 7 and the passage 8 constitute a conventionally known negative pressure booster system.

The drive current of the pump 12 is controlled in accordance with the magnitude of the brake operation detection signal from the pressure pickup 9, that is, the magnitude of the brake fluid pressure from the master cylinder 5, whereby the pump discharge pressure is controlled by the master. The control is performed according to the brake fluid pressure of the cylinder 5, in other words, according to the pedal effort. Further, the input / output characteristics of the pump 12 are determined so that the output of the pump 12 is equal to or less than the output of the master cylinder 5 when the negative pressure source 4 of the negative pressure booster 3 is normal and the negative pressure booster 3 is fully loaded. ing. As a method of determining the input / output characteristics in this way, there is a method of limiting the maximum current of the pump 12.

In the brake booster system 1 of the first embodiment constructed as described above, when the negative pressure source 4 is normal and a negative pressure exceeding a predetermined value is ensured, the pressure switch 5 operates to make the negative pressure. Since the pressure drop detection signal is not output, the ECU 16 holds the shutoff valve 10 at the communication position I and does not drive the pump 12.

When the brake pedal 2 is depressed in this state, the control valve (not shown) of the negative pressure booster 3 is switched, and the atmosphere flows into the variable pressure chamber (not shown) of the negative pressure booster 3. The power piston (not shown) moves forward, and the negative pressure booster 3 produces an output that boosts the pedal effort. As a result, the master cylinder 5 generates a brake fluid pressure, and the brake fluid pressure of one brake system is supplied to the brake cylinder 7 of the one brake system through the passage 8 and the open shutoff valve 10, and one brake system is braked. The normal brake of the system is operated by the output of the negative pressure booster 3. In that case, since the brake fluid pressure in the passage 8 does not leak to the reservoir 6 by the check valve 14, the brake fluid pressure is not lost, and the normal brake is reliably operated with a predetermined braking force. become. Further, the brake fluid of the other brake system of the master cylinder 5 is supplied to the brake cylinder 7 of the other brake system, and the normal brake of the other brake system is similarly operated by the negative pressure booster 3.

When the negative pressure source 4 fails and the negative pressure thereof drops below a very low predetermined value, the pressure switch 15 is turned on to issue a negative pressure failure detection signal. It is input to the ECU 16. The ECU 16 outputs an alarm signal to the alarm device 17 based on this negative pressure failure detection signal, and the alarm device 17 issues an alarm by lighting an alarm lamp, blowing an alarm buzzer, or the like. With this alarm, the driver knows that the negative pressure source 4 has failed.

By the way, it is assumed that the driver does not notice this warning and depresses the brake pedal 2 to perform the brake operation. In that case, in this state, both the negative pressure in the constant pressure chamber and the variable pressure chamber of the negative pressure booster 3 are reduced to a predetermined value or less and become substantially atmospheric pressure. Therefore, even if the brake pedal 2 is depressed to switch the control valve of the negative pressure booster 3, the negative pressure booster 3 does not operate by negative pressure. When the brake pedal 2 is further depressed, the power piston of the negative pressure booster 3 advances only by the pedal effort. As a result, the master cylinder 5 generates a brake fluid pressure only by the pedaling force, and this brake fluid pressure is supplied to the brake cylinder 7 of one brake system through the passage 8 and the brake cylinder 7 of the other brake system. Is supplied to. The brake fluid pressure generated only by such pedaling force is relatively small, and therefore the brake force generated by the brake cylinder 7 is also small.

However, in this case, when the brake fluid pressure in the passage 8 exceeds a predetermined pressure, this brake fluid pressure is detected by the pressure pickup 9, and this pressure pickup 9 supplies a brake operation detection signal to the ECU 16, so that the ECU
A pump 16 switches the shutoff valve 10 to the shutoff position II by a negative pressure failure detection signal from the pressure switch 15 and a brake operation detection signal from the pressure pickup 9 and the pump 1
Drive 2 As a result, the passage 8 is blocked, and the pump 12 sucks and discharges the brake fluid in the reservoir 6 to generate a discharge pressure, and this discharge pressure is supplied to the brake cylinder 7, so that the brake cylinder 7 is large. Braking force is generated. In that case, since the supply current of the pump 12 is controlled according to the magnitude of the brake operation detection signal of the pressure pickup 9, that is, the magnitude of the brake fluid pressure of the master cylinder 5, the discharge pressure of the pump 12 is the brake pressure of the master cylinder 5. The pressure controlled according to the hydraulic pressure, in other words, the pressure corresponding to the pedal effort, and therefore the braking force also has the magnitude corresponding to the pedal effort. Moreover, since the shut-off valve 10 is at the shut-off position II and shuts off the passage 8, the discharge pressure of the pump 12 does not leak to the master cylinder 5 and the pressure is not lost. The boosted braking force is surely obtained.

When the vehicle is stopped and the driver releases the brake pedal 2, the brake fluid pressure in the master cylinder 5, that is, the brake fluid pressure in the passage 8 on the master cylinder 5 side of the shutoff valve 10 disappears. 9 stops outputting the brake actuation signal. Therefore, the ECU 16
Switches the shut-off valve 10 to the communication position I to communicate the passage 8 and stops driving the pump 12. As a result, the brake fluid in the brake cylinder 7 is returned to the master cylinder 5, and the brake is released.

Brake boosting system 1 of the first embodiment
According to the above, the driver is notified by the alarm device 17 that the negative pressure source 4
You can know the failure of. If the driver does not notice this warning and depresses the brake pedal 2, the pump 12 is driven to generate a discharge pressure according to the pedal effort, and this discharge pressure is supplied to the brake cylinder 7 as a brake pressure. Therefore, an extremely large braking force can be obtained. Therefore, not only can the normal braking when the negative pressure source 4 fails, almost as reliably as the normal braking when the negative pressure source 4 is normal, but also the pedal effort can be reduced, and the vehicle is heavy. It becomes possible to reliably stop the vehicle with the normal brake and the vehicle with the sudden brake with a relatively small pedaling force and a short braking distance.

In this embodiment, when the negative pressure source fails, it is sufficient that the vehicle can be stopped without fail, and it is not necessary to control the brake fluid pressure of the brake cylinder 7 to be gradually reduced. However, when the vehicle is decelerated by the brake operation by the discharge pressure of the pump 12 when the negative pressure source fails, and the control is performed to reduce the brake fluid pressure of the brake cylinder 7, the ECU 16 controls the opening / closing of the shutoff valve 10. The supply current of the pump 12 may be controlled together.

Instead of the pressure pickup 9 for detecting the brake operation, the pedal operation force pickup for detecting the pedal operation force when the brake pedal 2 is depressed can be used for detecting the brake operation.

FIG. 2 is a diagram schematically showing a second embodiment of the present invention. The same components as those of the brake booster system of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The brake booster system 1 of the second embodiment is different from the brake booster system 1 of the first embodiment described above.
Is disposed in parallel with the pump 12 and the pair of check valves 13 and 14 in a passage 18 that bypasses the pump 12 and the pair of check valves 13 and 14, and is in communication with the cutoff position I.
A normally closed on-off valve 19 consisting of a solenoid valve provided with II and
Another pressure pickup 20 arranged in the passage 8 between the shut-off valve 10 and the brake cylinder 7 (second part of the present invention)
Corresponding to the pressure detection means). The opening / closing valve 19 and the pressure pickup 20 are both connected to the ECU 16, and the opening / closing valve 19 is controlled to be opened / closed by the ECU 16 and a detection signal of the brake fluid pressure detected by the pressure pickup 20 is input to the ECU 16. ing. Thus, in this second embodiment, the ECU 16 sets both pressure pickups so that the brake hydraulic pressure of the brake cylinder 7 to which the discharge pressure of the pump 12 is supplied becomes the hydraulic pressure corresponding to the brake hydraulic pressure of the master cylinder 5. 9,
The supply current of the pump 12 and the opening / closing of the on-off valve 19 are controlled based on both brake hydraulic pressure signals from 20.

In the brake booster system 1 of the second embodiment thus constructed, the pressure switch 15 does not operate when the negative pressure source 4 is normal, and does not output a negative pressure failure detection signal to the ECU 16. Therefore, the ECU 16 determines that the shutoff valve 1
0, the pump 12, the alarm device 17, and the opening / closing valve 19 are not operated. Therefore, at this time, the negative pressure booster 3 is depressed by depressing the brake pedal 2 as in the first embodiment.
The normal brake is activated by the output of.

When the negative pressure source 4 fails, the alarm device 17 issues an alarm, the shutoff valve 10 is switched to the shutoff position II, the passage 8 is shut off, the pump 12 is driven, and the discharge pressure of the pump 12 is reduced. A series of operations in which the brake is operated by being supplied to the brake cylinder 7 and the brake is released after the vehicle is stopped is performed in the same manner as in the first embodiment. However, in the second embodiment, the ECU 16 controls the supply current of the pump 12 and the opening / closing of the opening / closing valve 19 according to the brake fluid pressure of the master cylinder 5 and the brake fluid pressure of the brake cylinder 7. The brake fluid pressure of No. 7 is controlled to increase or decrease according to the brake fluid pressure of the master cylinder 5 and the brake fluid pressure of the brake cylinder 7. Therefore, according to the brake booster system 1 of the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above, but the brake fluid pressure in the brake cylinder 7 is set to the driver as compared with the first embodiment. It becomes possible to control more accurately according to the pedal effort of.

FIG. 3 is a diagram schematically showing a third embodiment of the present invention. The same components as those in the brake booster system 1 of the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted.

The brake booster system 1 of the third embodiment is different from the brake booster system 1 of the first embodiment described above.
The present invention relates to an anti-skid control system (hereinafter referred to as AB
S) is applied to the brake booster system. ABS is a system that adjusts the braking force of the braking wheels so that the locking tendency is eliminated when the braking wheels tend to lock during vehicle braking.

As shown in FIG. 3, the third embodiment further includes
A normally-closed on-off valve 21, which is an electromagnetic valve disposed in a passage 11 between the reservoir 6 of the master cylinder 5 and the check valve 13, and has a shut-off position I and a communication position II, and a shut-off valve 10. In the passage 8a between the brake cylinder 7 and the brake cylinder 7, the downstream side of the position where the passage from the check valve 14 joins (the brake cylinder 7
A proportional control valve 22 formed of a solenoid valve which is arranged in the passage 8a of the side) and which outputs in proportion to the input based on the supply current, and a low pressure accumulator connected to the discharge port of the proportional control valve 22 by the passage 23. A sump 24 and a passage 25 that connects the passage 11 of the port of the opening / closing valve 21 on the pump 12 side to the sump 24 are provided. In that case, pump 12, E
The CU 16, the proportional control valve 22, the passage 23, the sump 24, and the passage 25 are components of this ABS.

The proportional control valve 22 is, for example, Japanese Patent Laid-Open No. 3-27.
Since it is a conventionally known proportional control valve as disclosed in Japanese Patent No. 6853, the description of its specific structure will be omitted, but its input, that is, the liquid input from the passage 8a according to the control current from the ECU 16 is omitted. The pressure is linearly controlled (for example, in the one disclosed in JP-A-3-276853, the input is linearly reduced and controlled according to the control current) and is output to the brake cylinder 7. The pressure reduction control of the brake cylinder 7 in the proportional control valve 22 is performed by discharging the brake fluid in the brake cylinder 7 from the discharge port of the proportional control valve 22 to the sump 24.

These on-off valve 21 and proportional control valve 22
Are both connected to the ECU 16 and controlled by the ECU 16. And this makes this third
In the embodiment, the ECU 16 sends a brake operation detection signal from the pressure pickup 9 so that the brake hydraulic pressure of the brake cylinder 7 to which the discharge pressure of the pump 12 is supplied becomes a hydraulic pressure corresponding to the brake hydraulic pressure of the master cylinder 5. Based on this, the supply current of the pump 12 and the supply current of the proportional control valve 22 are controlled.

In the thus configured brake booster system 1 of the third embodiment, the shut-off valve 10 and the proportional control valve 22 do not operate when the negative pressure source 4 of the negative pressure booster 3 is normal. It operates similarly to the first embodiment described above. When the negative pressure source 4 fails, the ECU 16 operates the alarm device 17 to give an alarm and the shutoff valve 1 in response to a negative pressure failure detection signal from the pressure switch 15 as in the first embodiment.
0 to shut-off position II to shut off passage 8 and pump 12
Drive. At the same time, the ECU 16 causes the open / close valve 2
1 is set to the blocking position II and the passage 11 is opened. As a result, similarly to the case of the first embodiment, the pump 12 sucks in and discharges the brake fluid in the reservoir 6, the discharge pressure is supplied to the brake cylinder 7 through the proportional control valve 22, and the brake operates, A series of operations of releasing the brake after the vehicle is stopped is performed.

However, in the third embodiment, the ECU 16
Is supplied from pressure pickup 9 master cylinder 5
The supply current of the pump 12 and the supply current of the proportional control valve 22 are controlled in accordance with the brake hydraulic pressure. As a result, the output of the proportional control valve 22 is linearly controlled according to the supply current, so that the brake fluid pressure of the brake cylinder 7 is controlled according to the brake fluid pressure of the master cylinder 5, as shown in FIG. . In that case, the proportional control valve 22 is controlled so that the characteristic of the brake fluid pressure shown in FIG. 4 is matched with the input / output characteristic of the brake fluid pressure by the negative pressure booster 3 and the pair pedaling force of the brake pedal 2. As a result, even when the negative pressure source 4 fails, it is possible to obtain the same braking force as when the negative pressure source 4 is normal. According to the brake booster system 1 of the third embodiment, it is possible to obtain the same effects as the second embodiment.

The control of the ABS in the third embodiment is performed by the ECU 16 closing the shut-off valve 10 when the ECU 16 detects a wheel locking tendency during vehicle braking by a wheel speed signal from a wheel speed sensor (not shown). The pump 12 is driven and the proportional control valve 22 is further controlled so that the brake fluid in the brake cylinder 7 of the wheel is sump 24.
To reduce the brake fluid pressure of the brake cylinder 7, and when the wheel speed of the wheel recovers a predetermined amount, the discharge pressure of the pump 12 is supplied to the brake cylinder 7 to increase the brake fluid pressure of the brake cylinder 7 again. , Done.

Further, the two brake cylinders 7, 7 of one brake system are used as the brake cylinders of the left and right driving wheels of the vehicle, and the ECU 16 controls not only ABS but also traction control (hereinafter referred to as TRC). By also performing the above, it becomes possible to perform the TRC when the drive wheels tend to idle when starting or accelerating. That is, when the ECU 16 detects the idling tendency of the driving wheels based on the wheel speed signal from a wheel speed sensor (not shown) that detects the wheel speeds of the left and right driving wheels, E
The CU 16 controls the pump 12, the shutoff valve 10, the on-off valve 21, and the proportional control valve 22 to apply the braking force according to the idling tendency amount to the drive wheels, so that the idling tendency of the drive wheels is eliminated. , It becomes possible to adjust the driving force of the drive wheels.

FIG. 5 is a diagram schematically showing a fourth embodiment of the present invention. The same components as those of the brake booster system 1 of the first and third embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted.

The brake booster system 1 of the fourth embodiment is different from the brake booster system 1 of the first embodiment described above.
Is applied to a brake booster system equipped with an ABS as in the case of the third embodiment. As shown in FIG. 5, a normally closed on-off valve 21 provided in a passage 11 and a brake cylinder 7 are provided. A sump 24 connected by a selectively connectable passage 23, a passage 25 connecting the passage 11 of the pump 12 side port of the opening / closing valve 21 to the sump 24, and a passage between the shutoff valve 10 and the brake cylinder 7. Check valve 1 with 8a
The normally open shutoff valve 26, which is provided in the passage 8a on the downstream side (brake cylinder 7 side) from the position where the passage from 4 merges, and which is provided with the communication position I and the shutoff position II, and the check valve 14. An accumulator 27 provided at a downstream position and a switching valve 28 for selectively switching and connecting the brake cylinder 7 to the passage 8a or the passage 23 are provided. In the fourth embodiment, the check valve 13 is provided in the passage 25. Shutoff valve 10, pump 12, ECU 16, passage 23, sump 2
4, the passage 25, the shutoff valve 26, the accumulator 27 and the switching valve 28 are used as components of the ABS and TRC.

The on-off valve 21 is provided with a shut-off position I and a communication position II, which is normally set to the shut-off position I, and is controlled by the ECU 16 at the time of pressure source failure, ABS operation and TRC operation. The communication signal is set to the communication position II. Further, the shutoff valve 26 has a pilot pressure for controlling the switching of the shutoff valve 26.
The brake fluid pressure of the master cylinder 5 acts on the shut-off valve 26 in the communication position I, and the brake fluid pressure of the brake cylinder 7 acts on the shut-off valve 26 in the shut-off position II. The valve 26 is set to the communication position I during normal operation, pressure source failure, ABS pressure increasing control, and TRC operation, and the pressure of the brake cylinder 7 is the same as during the ABS pressure reducing control. 26
When the predetermined pressure is larger than the larger one of the pressures before and after, the cut-off position II is set. Further, the switching valve 28 is provided with a first position I that connects the passage 8 and disconnects the brake cylinder 7 and the passage 23, and a second position II that disconnects the passage 8 and connects the brake cylinder 7 and the passage 23. Has been. And during normal times, when pressure is lost, AB
It is set to the first position I during S pressure increase control and TRC operation, and is set to the second position II during ABS pressure reduction control and TRC operation release. In FIG. 5, 36
Is an aperture.

Also in the fourth embodiment, the ECU 16 controls the pressure pickup 9 so that the brake hydraulic pressure of the brake cylinder 7 to which the discharge pressure of the pump 12 is supplied becomes a hydraulic pressure corresponding to the brake hydraulic pressure of the master cylinder 5. The supply current of the pump 12 and the opening / closing of the switching valve 28 are controlled based on the brake operation detection signal from the.

In the brake booster system 1 of the fourth embodiment thus constructed, when the negative pressure source 4 of the negative pressure booster 3 is normal, it operates in the same manner as in the first embodiment.
When the negative pressure source 4 fails, the ECU 16 receives the negative pressure failure detection signal from the pressure switch 15 as in the first embodiment.
Activates the alarm device 17 to issue an alarm, turns on the shutoff valve 10 to the shutoff position II, and closes the shutoff valve 21.
Turn on to shut off position II and open. At the same time, EC
U16 also drives the pump 12. As a result, the discharge pressure of the pump 12 is supplied to the brake cylinder 7 through the cutoff valve 22 and the switching valve 28 to activate the brake, and the brake is released after the vehicle is stopped, similar to the case of the first embodiment. Is operated.

However, in the fourth embodiment, the ECU 16
Is supplied from pressure pickup 9 master cylinder 5
The supply current of the pump 12 and the supply current of the proportional control valve 22 are controlled in accordance with the brake hydraulic pressure. As a result, the brake fluid pressure of the brake cylinder 7 is controlled according to the brake fluid pressure of the master cylinder 5. In that case, the characteristics of the brake fluid pressure in the brake booster system 1 shown in FIG. 5 are matched with the input / output characteristics of the brake fluid pressure by the negative pressure booster 3 and the pedal effort of the brake pedal 2.
By controlling the pump 12, even when the negative pressure source 4 fails, the same braking force as that when the negative pressure source 4 is normal can be obtained.

Brake boosting system 1 of the fourth embodiment
According to the above, it is possible to obtain the same effect as that of each of the above-described embodiments. Since the ABS operation and the TRC operation in the fourth embodiment are almost the same as those in the third embodiment, the description thereof will be omitted.

FIG. 6 is a diagram schematically showing a fifth embodiment of the present invention. The same components as those of the brake booster system of the first embodiment described above are designated by the same reference numerals,
Detailed description thereof will be omitted.

The brake booster system 1 of the fifth embodiment is different from the brake booster system 1 of the first embodiment described above.
Eliminates the pressure pickup 9 of the first embodiment, and
A pressure adjusting valve 29 is provided in the passage 11 between the discharge side of the pump 12 and the check valve 14, and the pressure adjusting valve 29 is provided.
Is controlled by the hydraulic pressure of the master cylinder 8. That is, the pressure adjusting valve 29 adjusts the discharge pressure of the pump 12 to the master cylinder pressure, in other words, the magnitude corresponding to the pedaling force, and supplies it to the brake cylinder 7. Although a specific configuration of the pressure adjusting valve 29 will not be described, a conventionally known pressure adjusting valve can be used as the pressure adjusting valve 29.

In the fifth embodiment as well, the same effect as that of the first embodiment can be obtained, but the brake fluid pressure of the brake cylinder 7 depends on the pedaling force of the driver as compared with the first embodiment. It becomes possible to control more accurately.

FIG. 7 is a diagram schematically showing a sixth embodiment of the present invention. The same components as those of the brake booster system 1 of each of the above-described embodiments are designated by the same reference numerals,
Detailed description thereof will be omitted.

In contrast to the brake booster system 1 of the fourth embodiment shown in FIG. 5, the sixth embodiment eliminates the pressure pickup 9 of the first embodiment and further reverses the pump 12 discharge side. A pressure adjusting valve 29 is provided in the passage 11 downstream of the stop valve 14.
In addition, the pressure adjusting valve 29 is controlled by the hydraulic pressure of the master cylinder 8. That is, by the pressure adjusting valve 29 as in the fifth embodiment,
The discharge pressure of the pump 12 is adjusted to a magnitude corresponding to the pedal effort and supplied to the brake cylinder 7. Also in the sixth embodiment, the same effect as that of the fourth embodiment can be obtained.

FIG. 8 is a diagram schematically showing a seventh embodiment of the present invention. The same components as those of the brake booster system 1 of each of the above-described embodiments are designated by the same reference numerals,
Detailed description thereof will be omitted.

In the above-mentioned first to sixth embodiments,
Although the case where the present invention is applied to the brake booster system 1 using the negative pressure booster 3 has been described, this seventh embodiment uses the hydraulic booster 30 as shown in FIG. It is an example corresponding to the first embodiment when the present invention is applied to the brake booster system 1.

The brake booster system 1 using the hydraulic booster 30 includes a main reservoir tank 31, a sub-reservoir tank 32, and a pump 33 for generating an operating pressure for boosting a normal brake. An accumulator 34 for accumulating the operating pressure and a pressure switch 35 that operates when the pressure of the accumulator 34 drops below a predetermined pressure are provided. The pump 33 sucks the hydraulic fluid from the main reservoir tank 31, and the accumulator 34 and the pressure chamber 30 of the hydraulic booster 30.
The pressure is discharged to a and the pressure is accumulated in the accumulator 34 and the pressure chamber 30a. When the brake is operated, the control valve 30c of the hydraulic booster 30 is switched by depressing the brake pedal 2, and the pressure in the pressure chamber 30a is introduced into a power chamber (not shown) of the hydraulic booster 30. As a result, the power piston (not shown) of the hydraulic pressure booster 30 moves forward to move the piston (not shown) of the master cylinder 3 forward, and the master cylinder 5 generates brake hydraulic pressure. Further, when the brake is released, the control valve 30c is switched back to the original state by releasing the brake pedal 2, the hydraulic fluid in the power chamber is discharged to the sub-reservoir tank 32 through the low-pressure chamber 30b, and then to the main reservoir tank 31. It

Other constitutions such as a constitution for securing the braking force at the time of pressure failure are exactly the same as those of the first embodiment. Therefore, in the first embodiment, the negative pressure failure is detected by the pressure switch 15, whereas the seventh embodiment is different in that the hydraulic pressure failure is detected by the pressure switch 35. The effects of the seventh embodiment are the same as those of the first embodiment.

In the brake booster system 1 using the hydraulic booster 30, it is necessary to fill the low pressure chamber 30b with hydraulic fluid in order to prevent rusting of the components inside the hydraulic booster 30. There is. For this reason, the reservoir tank is generally placed at the highest position, then the hydraulic booster is placed at a position lower than the reservoir tank, and the pump is placed at a position lower than the hydraulic booster. They are arranged close to each other. In particular, it is essential that the pump and the reservoir tank are arranged close to each other in terms of pump performance. However, depending on the vehicle, the pump and the hydraulic booster may have to be arranged separately. In this case, the reservoir tank approaching the pump is arranged at a position lower than the hydraulic booster, and as a result, the low pressure chamber of the hydraulic booster may not always be filled with hydraulic fluid. is there.

Therefore, in the seventh embodiment, as shown in FIG.
When the pump 33 and the hydraulic booster 30 are arranged apart from each other as shown in FIG. 2, the main reservoir tank 31 is arranged close to the pump 3, and the sub-reservoir tank 32 having a smaller volume than the main reservoir tank 31 is arranged. Is arranged close to the low pressure chamber 30b of the hydraulic booster 30 so that the hydraulic fluid that overflows in the sub-reservoir tank 32 is supplied to the main reservoir tank 31.

By thus dividing the reservoir tank into two, even if the main reservoir tank 31 is arranged at a position lower than the hydraulic booster 30 when the main reservoir tank 31 is arranged close to the pump 33, Since the reservoir tank 32 can be arranged at a position higher than the hydraulic booster 30, the hydraulic fluid is transferred to the hydraulic booster 3
It is possible to reliably fill the low pressure chamber 30b of 0. As a result, it is possible to reliably prevent rusting of parts inside the hydraulic booster 30.

FIG. 9 is a diagram schematically showing an eighth embodiment of the present invention. The same components as those of the brake booster system 1 of each of the above-described embodiments are designated by the same reference numerals,
Detailed description thereof will be omitted.

In the seventh embodiment described above, the sub-reservoir tank 32 is independently provided in the brake booster system 1 using the hydraulic booster 30, whereas in the eighth embodiment, As shown in 9, the sub-reservoir tank 3
2 is provided integrally with the reservoir 6 of the master cylinder 5. The other structure of the eighth embodiment is exactly the same as that of the seventh embodiment. In the eighth embodiment, since the sub-reservoir tank 32 and the reservoir 6 are integrated, the number of parts is reduced and the number of assembling steps is reduced as compared with the seventh embodiment. Other operational effects of the eighth embodiment are exactly the same as those of the seventh embodiment.

[0076]

As is apparent from the above description, according to the brake boosting system of the present invention, when the brake operation is performed by depressing the brake pedal at the time of pressure failure, the discharge pressure generated by the pump is As a result, the brake can be applied with a large braking force.
It is possible to reliably obtain a braking force that is greatly boosted by the pedal effort. Particularly, according to the invention of claim 2, since the pump discharge pressure is controlled according to the pedal effort of the brake pedal, it is possible to obtain the braking force according to the pedal effort of the brake pedal. Therefore, not only can the normal braking when the pressure source fails, almost as securely as the normal braking when the pressure source is normal, but also the pedal effort can be reduced and the normal braking of a heavy vehicle can be performed. It becomes possible to reliably stop the vehicle or stop the vehicle by sudden braking with a relatively small pedaling force and a short braking distance.

Further, according to the third to seventh aspects, the braking force can be more surely responded to the pedaling force of the brake pedal, and the braking feeling is almost the same as the normal braking when the pressure source is normal. be able to.

Further, according to the invention of claim 10, since it becomes possible to surely fill the low pressure chamber of the hydraulic booster from the second reservoir tank, the components in the hydraulic booster It is possible to reliably prevent rusting.

[Brief description of drawings]

FIG. 1 is a first brake boosting system according to the present invention.
It is a figure which shows an Example typically.

FIG. 2 is a diagram schematically showing a second embodiment of the present invention.

FIG. 3 is a diagram schematically showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a brake characteristic of a third embodiment.

FIG. 5 is a diagram schematically showing a fourth embodiment of the present invention.

FIG. 6 is a diagram schematically showing a fifth embodiment of the present invention.

FIG. 7 is a diagram schematically showing a sixth embodiment of the present invention.

FIG. 8 is a diagram schematically showing a seventh embodiment of the present invention.

FIG. 9 is a diagram schematically showing an eighth embodiment of the present invention.

FIG. 10 is a diagram showing an example of a conventional brake booster system.

[Explanation of symbols]

1 ... Brake boost system, 2 ... Brake pedal, 3 ...
Negative pressure booster, 4 ... Negative pressure source, 5 ... Master cylinder, 6 ...
Reservoir, 7 ... Brake cylinder, 8, 11, 18, 23,
25 ... passage, 9, 20 ... pressure pickup, 10, 26 ...
Shut-off valve, 12, 33 ... Pump, 13, 14 ... Check valve, 1
5,35 ... Pressure switch, 16 ... Electronic control unit (EC
U), 17 ... Alarm device, 19, 21 ... Open / close valve, 22 ... Proportional control valve, 24 ... Sump, 27, 34 ... Accumulator, 28 ... Changeover valve, 29 ... Pressure adjusting valve, 30 ... Hydraulic booster, 30b ... Low-pressure chamber, 31 ... Main reservoir tank,
32 ... Sub reservoir tank,

Claims (10)

[Claims] 1. A brake pedal, a pressure source for generating a fluid pressure, and a fluid pressure multiplier which is operated by stepping on the brake pedal and boosts and outputs the pedaling force of the brake pedal by the fluid pressure of the pressure source. Force device, a master cylinder that is actuated by the output of this fluid pressure booster to generate brake fluid pressure, a reservoir that stores the brake fluid that is supplied to and discharged from this master cylinder, and this brake fluid pressure that is supplied. In a brake booster system that includes a brake cylinder that generates a braking force and that generates a braking force that boosts the pedaling force of the brake pedal, a pressure is detected when the fluid pressure of the pressure source is below a predetermined pressure. A pressure detection means for outputting a power failure detection signal and a brake operation detection signal for detecting a brake operation by depressing the brake pedal. And a normally open shut-off valve including a solenoid valve provided in a first passage communicating the master cylinder and the brake cylinder and having a communicating position and a shut-off position, and the reservoir. Is connected to the first passage between the shutoff valve and the brake cylinder, and the brake fluid in the reservoir is provided between the shutoff valve and the brake cylinder. A pump that supplies the fluid to the first passage and a flow of the brake fluid that is provided in the second passage on the discharge side of the pump and that flows from the reservoir toward the first passage between the shutoff valve and the brake cylinder. When a check valve allowing the above, a pressure source failure detection signal from the pressure detection means, and a brake operation detection signal from the brake operation detection means are input, the shutoff is performed. An electronic control unit for driving and controlling the pump while setting a valve shutoff position, and when the brake operation is performed in a pressure source failure state, the brake operation is performed by the discharge pressure from the pump. A characteristic brake booster system. 2. The brake operation detection signal from the brake operation detection means is a signal according to the pedal effort of the brake pedal, and the electronic control unit supplies a current supplied to the pump according to the pedal effort of the brake pedal. The brake booster system according to claim 1, wherein the brake booster system is controlled. 3. A third passage connecting the second passage and the first passage between the shutoff valve and the brake cylinder by bypassing the pump and the check valve, and the third passage. A normally-closed on-off valve composed of a solenoid valve provided with a shut-off position and a communication position, and a fluid pressure in the first passage between the shut-off valve and the brake cylinder is detected to output a pressure signal. And a second pressure detecting means for outputting, wherein the electronic control unit supplies the supply current to the pump based on the brake operation detecting signal from the brake operation detecting means and the pressure signal from the second pressure detecting means. 3. The brake force of the brake operation by the discharge pressure from the pump is controlled according to the depression force of the brake pedal by controlling the opening and closing of the open / close valve, respectively. Brake boost system. 4. A normally-closed on-off valve, which is an electromagnetic valve provided in the second passage between the reservoir and the pump, and has a shut-off position and a communication position, and a discharge pressure from the pump. And a proportional control valve for controlling and outputting, wherein the electronic control unit controls the opening / closing valve based on the pressure source failure detection signal from the pressure detection means and the brake operation detection signal from the brake operation detection means. Is set to a communication position and the supply current to the pump and the proportional control valve are respectively controlled based on the brake operation detection signal, so that the braking force of the brake operation by the discharge pressure from the pump is applied to the brake. The brake boosting system according to claim 2, wherein the brake boosting system is controlled according to the pedaling force of the pedal. 5. A normally-closed on-off valve, which is an electromagnetic valve disposed in the second passage between the reservoir and the pump, having a shut-off position and a communication position, the on-off valve and the pump. Between a third passage branched from the second passage between the shutoff valve and the brake cylinder, and a first passage on the brake cylinder side from a confluence position between the first passage and the second passage between the shutoff valve and the brake cylinder. The first cylinder disposed between the shut-off valve and the brake cylinder.
A switching valve that is provided with a first position that connects to the passage and a second position that connects the brake cylinder to the third passage, and is normally set to the first position; and the merging position and the switching valve. A normally open second passage which is disposed in the first passage between the two, is provided with a communication position and a cutoff position, and is set to the cutoff position when the brake fluid pressure of the brake cylinder is higher than the pressure at the confluence position by a predetermined pressure. A shutoff valve, and the electronic control unit sets the open / close valve to a communication position based on the pressure source failure detection signal from the pressure detection means and the brake operation detection signal from the brake operation detection means. Further controlling the supply current to the pump and the switching valve on the basis of the brake operation detection signal, and the brake fluid pressure of the brake cylinder to control the supply current. By opening and closing control of the second shutoff valve, the brake booster system of claim 2, wherein the control according to the braking force of the brake operation by the discharge pressure from the pump to the depression force of the brake pedal. 6. A brake pedal, a pressure source for generating a fluid pressure, and a fluid pressure multiplier that is operated by stepping on the brake pedal and boosts and outputs the stepping force of the brake pedal by the fluid pressure of the pressure source. Force device, a master cylinder that is actuated by the output of this fluid pressure booster to generate brake fluid pressure, a reservoir that stores the brake fluid that is supplied to and discharged from this master cylinder, and this brake fluid pressure that is supplied. In a brake booster system that includes a brake cylinder that generates a braking force and that generates a braking force that boosts the pedaling force of the brake pedal, a pressure is detected when the fluid pressure of the pressure source is below a predetermined pressure. A pressure detection unit that outputs a source failure detection signal and a first passage that connects the master cylinder and the brake cylinder are arranged to communicate with each other. Normally open shut-off valve consisting of a solenoid valve provided with a shut-off position and a shut-off position, a second passage connecting the reservoir to the first passage between the shut-off valve and the brake cylinder, and the second passage. A pump that is provided to supply the brake fluid in the reservoir to the first passage between the shutoff valve and the brake cylinder, and a second passage that is on the discharge side of the pump, and that shuts off the reservoir from the reservoir. The first between the valve and the brake cylinder
A check valve that allows only the flow of the brake fluid toward the passage, and at least the second passage on the discharge side of the pump, the brake fluid pressure of the master cylinder is introduced as pilot pressure, and the magnitude of this pilot pressure is increased. When a pressure adjusting valve for adjusting the discharge pressure of the pump according to the input pressure and the pressure source failure detection signal from the pressure detecting means are input, the shutoff valve is set to the shutoff position and the pump is driven. And an electronic control device for controlling, when the brake operation is performed in a pressure source failure state, the discharge pressure from the pump is adjusted to the discharge pressure of the pump according to the magnitude of the brake hydraulic pressure of the master cylinder. A brake booster system characterized by adjusting the brakes. 7. A normally-closed on-off valve, which is an electromagnetic valve provided in the second passage between the reservoir and the pump, and provided with a blocking position and a communication position, the on-off valve and the pump. Between a third passage branched from the second passage between the shutoff valve and the brake cylinder, and a first passage on the brake cylinder side from a confluence position between the first passage and the second passage between the shutoff valve and the brake cylinder. The first cylinder disposed between the shut-off valve and the brake cylinder.
A switching valve formed of a solenoid valve that is provided with a first position that connects to a passage and a second position that connects the brake cylinder to the third passage, and is normally set to the first position; Disposed in the first passage between the switching valve,
The communication position and the shutoff position are provided, and the normally open second shutoff valve which is set to the shutoff position when the brake fluid pressure of the brake cylinder is higher than the pressure at the merging position by a predetermined pressure; Based on the pressure source failure detection signal from the pressure detecting means, the on-off valve is set to the communicating position and the switching valve is set to the second position, and the pump is drive-controlled, and the brake is applied in the pressure source failure state. 7. When the operation is performed, the discharge pressure from the pump is adjusted according to the brake fluid pressure of the master cylinder to perform the brake operation. Brake boost system. 8. The brake booster system according to claim 1, wherein the fluid pressure booster is a negative pressure booster. 9. The brake booster system according to claim 1, wherein the hydraulic booster is a hydraulic booster. 10. A first reservoir tank and a second reservoir tank that store hydraulic fluid supplied to and discharged from the hydraulic booster and are connected to each other, and are arranged separately from the hydraulic booster. And a normal brake booster pump for feeding the hydraulic fluid from the first reservoir tank to the hydraulic booster, the first reservoir tank being disposed in the vicinity of the normal brake booster pump. Is being done,
The brake booster system according to claim 9, wherein the second reservoir tank is disposed in the vicinity of the hydraulic booster.