JPH0986390A - Liquid pressure booster system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a pump capacity as well as to carry out a booster operation securely, even when a brake and a steering are operated simultaneously. SOLUTION: When a brake and a steering are operated simultaneously, in the condition the liquid pressure is accumulated in an accumulator 31 exceeding a specific value, and a flow rate limit valve 34 is set at a flow rate nonlimiting position I, the liquid pressure of the accumulator 31 is used to a brake boosting operation by a booster 28, and an operating liquid discharged from a pump 8, and not throttled by the flow rate limit valve 34 is used to a steering boosting operation by a power steering device 7. Consequently, since a sufficient operating liquid is fed to the power steering device 7 even in such a condition, two boosting operations are carried out securely at a time, the capacity of the pump 8 can be reduced, furthermore, both operations give no influence each other, and no shock is generated to a handle 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake system which increases the braking force by boosting the pedaling force of a brake pedal in an automobile, for example, with the power of hydraulic fluid.
The present invention relates to a hydraulic pressure boosting system for a vehicle in which hydraulic fluid is shared with a power steering system that boosts steering force by boosting steering wheel operating force with hydraulic fluid power.

[0002]

2. Description of the Related Art Some vehicles such as automobiles use a hydraulic boosting system for a vehicle that boosts an operating force of an operating member by hydraulic pressure of hydraulic fluid and outputs the boosted force. This hydraulic boosting system for a vehicle is, for example, a hydraulic brake booster that operates by hydraulic pressure of hydraulic fluid in order to obtain a large braking force that cannot be obtained only by the pedaling force of the brake pedal or to reduce the pedaling force. Operated by a hydraulic brake system that uses a force device to boost the pedaling force to operate the master cylinder, or to obtain a large steering force that cannot be obtained only with the steering wheel operating force or to reduce the steering wheel operating force. There is a power steering system or the like in which a steering wheel is steered by boosting a steering wheel operating force by using a power steering device which is operated by a hydraulic pressure of liquid.

Among such hydraulic boosting systems for vehicles are, for example, a hydraulic boosting system for vehicles in which hydraulic fluid is shared between a hydraulic brake system and a power steering system.

FIG. 4 is a view showing an example of a conventional hydraulic boosting system for a vehicle, and FIG. 5 is a sectional view showing a hydraulic brake booster used in this system. In the figure, 1 is a vehicle hydraulic pressure boosting system (hereinafter also simply referred to as hydraulic pressure boosting system), 2 is a brake pedal, and 3 is operated by the brake pedal 2 to boost and output a pedal effort. An open center type hydraulic brake booster (hereinafter also simply referred to as a booster) 4 which is the hydraulic brake booster described above is a tandem type master cylinder 5 which is operated by the output of the booster 3 to generate a brake hydraulic pressure. A brake cylinder that operates with brake fluid pressure from the master cylinder 4 to generate a braking force for each wheel, 6 is a steering wheel, and 7 is an open center type that is operated by the steering wheel 6 and boosts and outputs the steering wheel operating force. The power steering device 8 is driven by the engine 9 to transfer the hydraulic fluid to the booster 3 and the power steering device. A pump for supplying 7 to the reservoir 10, a reservoir for storing the hydraulic fluid, and 11 for storing a hydraulic fluid for operating the booster 3 when the hydraulic fluid is not delivered from the pump 8 due to a failure of the pump 8 or the like. Is an accumulator for.

In the open center type booster 3, the gap between the control valves is maximized when the brake is not operated, and the hydraulic fluid flows freely, and the flow of the hydraulic fluid is restricted by narrowing the gap between the control valves during the operation. A hydraulic pressure is generated and output by the hydraulic pressure, and various structures are conventionally known. An example of the booster 3 is shown in FIG. Since the booster 3 is conventionally known, a portion related to a problem to be solved by the present invention will be briefly described here.

In the brake non-operating state shown in FIG. 5, the gap between the first annular groove 12 and the second annular groove 13 is the maximum, and the second annular groove 13 and the third annular groove 14 are the same.
And the third annular groove 14 and the fourth annular groove 15 communicate with each other. Therefore, the pump 8
The hydraulic fluid discharged from the booster 3 of the open center type has a passage 16, a second annular groove 13, a first annular groove 12 and a second annular groove 12.
Gap between the annular groove 13, the first annular groove 12 and the passage 1
The fluid flows to the open center type power steering device 7 through 7, and then recirculates to the reservoir 10 again through the maximum clearance of the control valve (not shown) of the power steering device 7. In that case, the gap between the first annular groove 12 and the second annular groove 13 and the clearance of the control valve of the power steering device 7 are both maximum,
Almost no hydraulic pressure is generated in the circulating working fluid.

When a brake operation is performed by depressing the brake pedal 2 in this state, the input rod 18 moves forward, so that the spool 20 moves forward via the lever 19. Therefore, the gap between the first annular groove 12 and the second annular groove 13 is reduced, and the second annular groove 13 and the third annular groove 14 are formed.
And the third annular groove 14 and the fourth annular groove 15 are shut off. When the gap between the first and second annular grooves 12 and 13 is reduced, a hydraulic pressure is generated in the second annular groove 13. This hydraulic pressure is introduced into the power chamber 24 through the gap between the second annular groove 13 and the third annular groove 14, the radial passage 21, the longitudinal passage 22, and the radial passage 23, Acting on the power piston 25, the power piston 25
Generates a broom operation force that boosts the pedal effort, and this brake operation force is output from the output rod 26 to operate the master cylinder 4 and the brake is operated.

When the brake operation is released by releasing the brake pedal 2, the input rod 18 and the spool 2 are released.
0 retracts to the non-actuated position shown in FIG.
And the fourth annular groove 15 communicate with each other, the second annular groove 13 and the third annular groove 14 are blocked from each other, and the gap between the first annular groove 12 and the second annular groove 13 is maximized. For this reason,
The hydraulic fluid in the power chamber 24 passes through the passages 23, 22, 21, the third annular groove 14, the gap between the third annular groove 14 and the fourth annular groove 15, the fourth annular groove 15 and the passage 27, and then becomes a reservoir. 1
It is discharged to 0. As a result, the power piston 25 retracts to the non-actuated position, the brake operating force disappears, the master cylinder 4 returns to the non-actuated state, and the brake actuation is released. Further, since the gap between the first and second annular grooves 12 and 13 is maximized, the hydraulic pressure generated in the second annular groove 13 disappears.

On the other hand, the open center type power steering device 7 is a conventional general open center type power steering device, and when it is not operated, it is discharged from the pump 8 and flows into the power steering device 7 through the booster 3. The hydraulic fluid that comes in is returned to the reservoir 10 through the gap of the control valve provided inside. During this non-operation, no hydraulic pressure is generated on the upstream side of the control valve of the power steering device 7.

When the steering operation is performed by operating the steering wheel 6, the gap between the control valves is narrowed, so that hydraulic pressure is generated on the upstream side of the control valves. Since this hydraulic pressure acts on the power piston (not shown) of the power steering device 7,
The power piston operates to output a steering force that doubles the steering wheel operating force, and the steering force steers the wheels. Thus, the power steering operation is performed.

When the steering operation is released with the handle 6 position in the neutral position, the clearance between the control valves becomes maximum,
The hydraulic pressure generated on the upstream side of the control valve disappears and the power steering operation is released.

[0012]

By the way, in such a hydraulic boosting system 1, when the gap between the first annular groove 12 and the second annular groove 13 is narrowed by the brake operation, the pump 8 Most of the hydraulic fluid discharged from the pump is consumed for the operation of the booster 3, so that the amount of hydraulic fluid supplied to the power steering device 7 is reduced. Therefore, when the brake operation and the steering operation are performed at the same time, there is a possibility that the boosting action of the power steering device 7 may not be sufficiently performed.

Therefore, in order to ensure that both the simultaneous operation of the brake and the steering can be performed, a sufficient amount of hydraulic fluid is supplied to the power steering device 7 at the time of simultaneous operation. Although it is necessary, the pump 8 must be a large-capacity pump for that purpose, and there is a problem that the cost becomes high.

The present invention has been made in view of such circumstances, and its object is to provide a first operating member and a second operating member.
It is an object of the present invention to provide a hydraulic boosting system for a vehicle that can surely perform a boosting action even when the operating members are simultaneously operated and that can reduce the pump capacity as much as possible.

[0015]

In order to solve the above-mentioned problems, the invention of claim 1 provides a reservoir for storing a working fluid,
First for sucking and discharging the hydraulic fluid in the reservoir
A pump, an accumulator that stores the hydraulic pressure of the hydraulic fluid discharged from the first pump, a first operating member, and a first control valve that is normally closed are opened by the operation of the first operating member to open the first accumulator. A first closed center type which outputs an operating force of the first operating member by multiplying the operating force of the first operating member by the first hydraulic pressure from the accumulator when the first hydraulic pressure is introduced into the power chamber and acts on the first power piston. The hydraulic booster, the second operating member, and the working fluid normally discharged from the first pump freely flow through the gap of the second control valve provided inside and recirculate to the reservoir. , The second
By narrowing the gap of the second control valve when operating the operating member, the hydraulic fluid generates a second hydraulic pressure and
A second hydraulic booster of an open center type, which hydraulically acts on a second power piston provided inside to boost the operating force of the second operating member by the second hydraulic pressure and output the boosted force. And a supply passage for supplying the hydraulic fluid discharged from the first pump to the second hydraulic booster, and at a flow rate unlimited position that normally does not limit the flow rate of the hydraulic fluid flowing through the supply passage. A flow rate limiting valve that is set and switched when necessary to set a flow rate limiting position that limits the flow rate of the hydraulic fluid in the supply passage, and is turned on when the hydraulic pressure of the accumulator is below a predetermined value to detect a decrease in hydraulic pressure. A pressure detection unit that outputs a signal, a brake operation detection unit that is turned on when a brake operation is performed and outputs a brake operation signal, and a brake operation detection unit that is turned on when a steering operation is performed and outputs a steering operation signal. When the steering pressure detecting means that applies force and the hydraulic pressure decrease detection signal are not output from the pressure detecting means, the flow rate limiting valve is set to the flow rate unlimited position, and when the hydraulic pressure decrease detection signal is output, When the flow rate limiting valve is set to the flow rate limiting position and the flow rate limiting valve is set to the flow rate limiting position, no brake operation signal is output from the brake operation detecting means, and the steering operation is detected. Only when the steering operation signal is output from the means, the flow rate limiting valve is set to the flow rate unlimited position,
A control device for switching and controlling the flow rate limiting valve is provided.

According to a second aspect of the invention, a reservoir for storing the working fluid, a first pump for sucking and discharging the working fluid in the reservoir, and an accumulator for storing the hydraulic pressure of the working fluid discharged from the first pump. And the first operating member and the normally closed first control valve are opened by the operation of the first operating member, and the first hydraulic pressure of the accumulator is introduced to act on the first power piston. A closed center type first hydraulic pressure booster that boosts and outputs the operating force of the first operating member by the first hydraulic pressure from the accumulator, the second operating member, and the normal-time discharge from the first pump. The operated hydraulic fluid freely flows through the gap of the second control valve provided inside and recirculates to the reservoir, and the gap of the second control valve is narrowed when the second operation member is operated, Hydraulic fluid By generating the second hydraulic pressure and acting the second hydraulic pressure on the second power piston provided inside, the operating force of the second operating member is boosted by the second hydraulic pressure and output. An open center type second hydraulic booster and a supply passage for supplying the hydraulic fluid discharged from the first pump to the second hydraulic booster are provided, and normally flow through this supply passage. A flow rate limiting valve that is set to a flow rate unlimited position that does not limit the flow rate of the working fluid and is switched to a flow rate limiting position that is switched when necessary to limit the flow rate of the working fluid in the supply passage, the reservoir, and the first liquid. A pressure booster and a second pump provided in a bypass passage that bypasses the first pump and is connected to the second pump, and is turned on when the hydraulic pressure of the accumulator is equal to or less than a predetermined value to output a hydraulic pressure drop detection signal. Pressure detector A brake operation detecting means which is turned on when a brake operation is performed to output a brake operation signal, a steering operation detecting means which is turned on when a steering operation is performed and outputs a steering operation signal, and the pressure detecting means When the fluid pressure drop detection signal is not output from, the flow rate limiting valve is set to the flow rate unlimited position, and when the fluid pressure drop detection signal is output, the flow rate limiting valve is set to the flow rate limiting position, Further, when the flow rate limiting valve is set to the flow rate limiting position and the steering operation signal is output from the steering operation detecting means, the flow rate limiting valve is set to the flow rate unlimited position and When the restriction valve is set to the flow rate limiting position, the steering operation detecting means detects When the brake operation signal is output and the brake operation signal is output from the brake operation detecting means, the flow rate restricting valve and the flow rate restricting valve are set so as to set the flow rate restricting valve to the flow rate unlimited position and drive the second pump. And a control device for controlling the operation of the second pump.

According to a third aspect of the present invention, the first operating member is a brake operating member, the first hydraulic booster is a hydraulic brake booster, and the second operating member is a steering handle. The second hydraulic booster is a power steering device.

[0018]

According to the invention of claim 1 configured as described above, when the first hydraulic pressure of the accumulator becomes a predetermined value or less,
The pressure detecting means detects this and outputs a liquid pressure drop detection signal. The control device switches the flow rate limiting valve based on the liquid pressure drop detection signal to set the flow rate limiting position. Therefore, the amount of hydraulic fluid discharged from the pump and flowing through the flow rate limiting valve to the second hydraulic booster is limited, and hydraulic pressure is generated on the upstream side of the flow rate limiting valve, and this hydraulic pressure is stored in the accumulator. To be

When the first hydraulic pressure of the accumulator is stored to exceed the predetermined value, the pressure detecting means does not output the hydraulic pressure drop detection signal and the control device sets the flow rate limiting valve to the flow rate unlimited position. As a result, the hydraulic fluid flowing through the flow restriction valve is not restricted. In this state, when the first operating member is operated, the first control valve of the first hydraulic pressure booster opens, and the first hydraulic pressure of the accumulator is introduced into the first hydraulic pressure booster to cause the first hydraulic pressure booster to move to the first hydraulic pressure booster. Acts on the power piston. As a result, the first power piston boosts and outputs the operating force of the first operating member. Further, when the second operating member is operated in this state, the gap of the second control valve of the second hydraulic booster is narrowed and the flow rate of the hydraulic fluid from the pump is limited, so that the second hydraulic pressure is increased. The second hydraulic pressure is generated and acts on the second power piston of the second hydraulic booster.
As a result, the second power piston boosts and outputs the operating force of the second operating member.

Further, when both the first and second operating members are operated, the first hydraulic booster uses the first hydraulic pressure of the accumulator and the second hydraulic booster uses the pump. A hydraulic fluid is used to boost each of them. In that case, even if both the first and second operating members are operated, the working fluid from the pump supplied to the second hydraulic booster is sufficiently secured, so that the capacity of the pump can be reduced. . Moreover, since the first and second hydraulic boosters use independent hydraulic pressures, they do not affect each other. Therefore, a shock is not generated in the second operation member, and the operation feeling of the second operation member is improved.

According to the second aspect of the present invention, in addition to the above-mentioned function, even if the first pump fails, the first pump is operated by the first pump.
Since the pressure for the hydraulic booster is secured, the boosting action by the first hydraulic booster can be reliably performed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a vehicle hydraulic boosting system according to the present invention. The same components as those of the conventional system shown in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the conventional system shown in FIG. 4 described above, the open center type hydraulic brake booster 3 is used as the brake booster, but the hydraulic boosting system 1 of the first embodiment is an open center type hydraulic brake booster system. Instead of the rick brake booster 3, as shown in FIG. 1, a closed center type hydraulic brake booster 2 is provided.
8 is used. In the brake-side supply passage 29 connecting the pump 8 and the booster 28, a check valve 30 that allows only the flow of the hydraulic fluid from the pump 8 to the booster 28, an accumulator 31 that accumulates a predetermined hydraulic pressure, and an accumulator. A pressure switch 32 for detecting the hydraulic pressure of 31 is arranged in this order from the upstream side. The pressure switch 32 is turned on when the hydraulic pressure of the accumulator 31 becomes a predetermined value or less, and outputs a hydraulic pressure drop detection signal.

A power steering side supply passage (hereinafter also referred to as a PS supply passage) is branched from a brake side supply passage 29 between the pump 8 and the check valve 30 and connected to the open center type power steering device 7.
33 are provided. The PS supply passage 33 is provided with a flow rate limiting valve 34 which is an electromagnetic valve and which is set at two positions, a flow rate unlimited position I and a flow rate limiting position II by the orifice 34a. The flow rate limiting valve 34 is normally set to the flow rate unlimited position I, and the PS side supply passage 3
Although the flow rate of the hydraulic fluid flowing through No. 3 is not limited at all, when the flow rate limiting position II is set, the flow rate of the hydraulic fluid flowing through the PS side supply passage 33 is limited so that the hydraulic pressure is upstream. It is supposed to occur. And the flow control valve 3
4 is normally set to the flow rate unlimited position I shown in FIG.

Pressure switch 32 and flow rate limiting valve 34
Are both electronic control units (hereinafter, also referred to as ECU) 35
It is connected to the. The ECU 35 uses the brake operation signal from the brake switch 36 and the handlebar switch 37.
The flow rate limiting valve 34 is controlled in the following manner based on the steering operation signal from the pressure switch 32 and the hydraulic pressure decrease detection signal from the accumulator 31 from the pressure switch 32.

That is, the ECU 35 has the accumulator 3
When the fluid pressure of No. 1 exceeds a predetermined value and the fluid pressure drop detection signal is not input from the pressure switch 32, the flow rate limiting valve 34
Is set to the unrestricted flow rate position I without switching, and in this state, the unrestricted flow rate control valve 34 is left in the unrestricted flow rate restriction position even if a signal is input from at least one of the brake switch 36 and the handle switch 37. Hold on to I. Further, when the hydraulic pressure of the accumulator 31 becomes equal to or lower than a predetermined value and the hydraulic pressure decrease detection signal is input from the pressure switch 32, the ECU 35 determines that the flow rate limiting valve 3
Switch 4 and set to flow rate limiting position II. Further ECU
In this state, 35 is at least the brake switch 36.
When the signal from is input, the flow rate limiting valve 34 is maintained at the flow rate limiting position II as it is, and the brake switch 36
When only the steering operation signal from the handlebar switch 37 is input without inputting the brake operation signal from the flow control valve 34, the flow rate limiting valve 34 is switched to the flow rate unlimited position I.
Set to.

The closed center type booster 50 is a conventionally known one, and an example thereof is Japanese Patent Application No. 2-120.
FIG. 2 shows a booster 50 disclosed in the microfilm of No. 897 (Jitsukaihei 4-76576). Since the detailed structure and detailed operation of the booster 50 are described in the above-mentioned microfilm, the operation will be briefly described here.

When the brake operation is performed in the brake non-operating state shown in FIG. 2, the input shaft 38 is moved forward to switch the control valve 39, and the power chamber 40 is moved to the accumulator 31.
Connected to. Therefore, the hydraulic fluid of a predetermined pressure from the accumulator 31 is passed through the passages 41, 42, 43, the control valve 39,
And to the power chamber 40 through the passages 44, 45, 46. As a result, the power piston 47 operates to generate a brake operating force that doubles the depression force of the brake pedal 2, and this brake operating force is output from the output shaft 48 to operate the master cylinder 4 so that the brake operates. It has become.

When the brake is released, the input shaft 3
The power chamber 40 is connected to the reservoir 10 by retracting the control valve 39 to the non-actuated position shown in FIG. Therefore, the hydraulic fluid in the power chamber 40 is
It is discharged to the reservoir 10 through 45, 44, the control valve 39, the passages 49, 50, 51, 52 and the discharge passage 53. As a result, the power piston 47 retracts to the non-actuated position, the brake operating force disappears, the master cylinder 4 returns to the non-actuated state, and the brake actuation is released. The other structure of the first embodiment is the same as the structure of the conventional system shown in FIG.

The operation of the first embodiment thus constructed will be described. 1 and 2 when the brake is not operated, the power steering is not operated, and the hydraulic pressure exceeding a predetermined value is stored in the accumulator 31.
The state shown in FIG. While the engine 9 is operating in this state of the system 1, the pump 8 is being driven, so that the hydraulic fluid in the reservoir 10 is discharged from the pump 8,
A part of the brake side supply passage 29, the PS side supply passage 33,
It is recirculated to the reservoir 10 through the flow rate limiting valve 34 set to the unlimited position I and the power steering device 7. At this time, since the flow rate limiting valve 34 is set to the unlimited position I, the PS side supply passage 33 is not throttled at all and the flow rate of the hydraulic fluid flowing therethrough is not limited at all. Therefore, almost no hydraulic pressure is generated on the upstream side of the flow rate limiting valve 34.

In this state, when the hydraulic pressure of the accumulator 31 becomes equal to or lower than a predetermined value due to brake operation or the like, the pressure switch 32 is turned on and a hydraulic pressure decrease detection signal is input to the ECU 35. Since the ECU 35 switches and sets the flow rate limiting valve 34 to the flow rate limiting position II based on this detection signal, the PS side supply passage 33 is throttled and the flow rate of the hydraulic fluid flowing therethrough is limited. Liquid pressure is generated in the. This hydraulic pressure is stored in the accumulator 31. When the hydraulic pressure of the accumulator 31 exceeds a predetermined value, the pressure switch 32 is turned off, so that the ECU 35 switches the flow rate limiting valve 34 to the flow rate unlimited position I and enters the non-operation state.

When the brake operation is performed in a state where the hydraulic pressure is stored in the accumulator 31 in excess of a predetermined value and the flow rate limiting valve 34 is set to the flow rate unlimited position I, the brake by the booster 28 is applied. The boosting action is performed by the hydraulic pressure of the accumulator 31. As a result, the booster 28 reliably performs the brake boosting action. When the hydraulic pressure of the accumulator 31 and the flow rate limiting valve 34 are steered in this state, the steering boosting action of the power steering device 7 is discharged from the pump 8 and is not throttled by the flow rate limiting valve 34. It is performed by the liquid pressure generated by the power steering device 7 squeezing the liquid. As a result, the power steering device 7 surely performs the steering boosting action.

When the hydraulic pressure of the accumulator 31 is below a predetermined value and the flow rate limiting valve 34 is switched to the flow rate limiting position II, and the brake operation is performed, the boosting action of the brake booster 28 increases the flow rate. This is performed by the hydraulic pressure generated on the upstream side of the restriction valve 34. At this time, when the steering operation is further performed, the steering operation signal from the handlebar switch 37 is input to the ECU 35. The ECU 35 holds the flow rate restricting valve 34 at the flow rate restricting position II without switching, and the booster 28 increases the brake force. The force action is reliable. In this case, since the flow rate of the hydraulic fluid supplied to the power steering apparatus 7 is limited by the flow rate limiting valve 34, the steering boosting action by the power steering apparatus 7 is not always sufficiently performed.

When the steering operation is performed with the hydraulic pressure and flow rate limiting valve 34 of the accumulator 31 in this state, the steering wheel switch 37 is turned on and the steering operation signal is input to the ECU 35. In this steering operation state, when the brake operation is not performed, the brake switch 36 is turned off and the brake operation signal is the ECU.
35 is not entered. At this time, the ECU 35 switches the flow rate limiting valve 34 to the flow rate unlimited position I in response to the steering operation signal from the handlebar switch 37. As a result, the hydraulic fluid is supplied to the power steering device 7 without being limited by the flow rate limiting valve 34, and the power steering device 7 reliably performs the steering boosting action. In this case, a hydraulic pressure is generated on the upstream side of the power steering device 7, but when the hydraulic pressure is higher than the hydraulic pressure of the accumulator 31, the hydraulic pressure is stored in the accumulator 31. Further, when the brake operation is performed in the steering operation state, the brake switch 36 is turned on and the brake operation signal is EC.
Input to U35. At this time, the ECU 35 holds the flow rate limiting valve 34 in the flow rate limiting position II without switching the flow rate limiting valve 34 by the brake operation signal from the brake switch 36 and the steering operation signal from the handlebar switch 37, and the boosting action of the brake by the booster 28 is exerted. It is done surely and safety is improved. In this case as well, the flow rate of the hydraulic fluid supplied to the power steering device 7 is limited by the flow rate limiting valve 34 in the same manner as described above, so that the steering boosting action by the power steering device 7 is not always sufficiently performed. .

As described above, in the first embodiment, when both the brake operation and the steering operation are performed while the hydraulic pressure exceeding the predetermined value is stored in the accumulator 31, the brake boosting action of the booster 28 is performed. The hydraulic pressure of the accumulator 31 is used, and the steering boosting action of the power steering device 7 is performed by the hydraulic pressure generated by squeezing the hydraulic fluid supplied from the pump 8. In that case, since the flow rate of the hydraulic fluid supplied from the pump 8 to the power steering device 7 is not limited at all even when the brake operation is performed, the hydraulic fluid is sufficiently supplied from the pump 8 to the power steering device 7. Will be supplied.

Therefore, even if the pump 8 is used both for the hydraulic brake boosting system and the power steering system, the capacity of the pump 8 can be reduced. Moreover, even if the brake operation and the steering operation are performed at the same time, the independent hydraulic pressures are used, so that the brake operation and the steering operation do not affect each other. As a result, the steering wheel 6 is not shocked and the steering operation feeling is improved.

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

As shown in FIG. 3, in the second embodiment, the brake side supply passage 2 further downstream from the reservoir 10 and the check valve 30 in the first embodiment shown in FIG.
9, a bypass passage 54 that connects the pump 8 and the check valve 30 by bypass, a second pump 55 arranged in the bypass passage 54, and a motor 56 that drives the second pump 55. A check valve 57 arranged in the bypass passage 54 on the downstream side of the second pump 55.
And

The ECU 3 in the second embodiment
5 controls the operation of the flow rate limiting valve 34 as follows. That is, the ECU 35 controls the accumulator 3
When the hydraulic pressure of No. 1 exceeds a predetermined value and the hydraulic pressure drop detection signal is not input from the pressure switch 32, the accumulator 3
When the hydraulic pressure of No. 1 becomes a predetermined value or less and the hydraulic pressure decrease detection signal is input from the pressure switch 32, and when the hydraulic pressure decrease detection signal is input, the brake operation signal from the brake switch 36 and the handlebar switch 37. When only one of the steering operation signals from is input,
The flow control valve 34 is actuated and controlled in the same manner as in the first embodiment. In this case, the ECU 35 does not drive the motor 56,
Therefore, the second pump 55 is not driven. When only the brake operation signal is input from the brake switch 36 while the hydraulic pressure drop detection signal is input from the pressure switch 32, the flow rate limiting valve 34 is turned off to set the flow rate unlimited position I, and The motor 56 may be driven to drive the second pump 55.

Further, when the brake operation signal from the brake switch 36 and the steering operation signal from the steering wheel switch 37 are both input while the hydraulic pressure drop detection signal is input, the ECU 35 switches the flow rate limiting valve 34. While setting the flow rate unlimited position I, the motor 56 is driven to drive the pump 55. The other structure of the second embodiment is the same as that of the first embodiment and the conventional system.

Next, the operation of the second embodiment will be described.
When the hydraulic pressure of the accumulator 31 becomes a predetermined value or less and the hydraulic pressure drop detection signal is input to the ECU 35, at least the brake operation signal from the brake switch 36 is transmitted to the ECU.
When input to 35, the ECU 35 sets the flow rate limiting valve 34 to the flow rate unlimited position I and drives the pump 55. As a result, the hydraulic fluid discharged from the pump 8 driven by the engine 9 is supplied to the power steering device 7 without being throttled by the flow rate limiting valve 34, and the booster 28 is discharged from the second pump 55. Liquid is supplied.

Therefore, when the hydraulic pressure of the accumulator 31 is below a predetermined value and at least the brake operation is performed, sufficient hydraulic fluid is supplied to both the booster 28 and the power steering device 7. Thus, when at least one of the brake operation and the steering operation is performed, both the brake boosting action and the steering boosting action corresponding to the operation are surely performed. become.

Further, in this embodiment, when the pump 8 due to the driving of the engine 9 fails and the hydraulic pressure of the accumulator 31 becomes below a predetermined value, the ECU 35 causes the pressure switch 32 to operate.
The motor 56 is driven by the hydraulic pressure drop detection signal from the.
Therefore, even if the pump 8 breaks down, the booster 28 can be operated by the hydraulic fluid discharged from the second pump 55, which improves safety. Other operational effects of the second embodiment are the same as the operational effects of the above-mentioned respective embodiments and the conventional system.

[0044]

As is apparent from the above description, according to the hydraulic boosting system for a vehicle of the present invention, the second hydraulic boosting system is operated even when both the first and second operating members are operated. Since the working fluid from the pump supplied to the apparatus is sufficiently secured, the capacity of the pump can be reduced and the cost can be reduced.

Since the first and second hydraulic boosters use independent hydraulic pressures, it is possible to prevent the mutual influences. Therefore,
A shock does not occur in the second operation member, and the operation feeling of the second operation member can be improved.

According to the second aspect of the present invention, even if the first pump fails, the second pump ensures the pressure for the first hydraulic booster. The boosting action by the pressure booster can be surely performed, and the safety is improved.

[Brief description of drawings]

FIG. 1 is a first hydraulic boosting system for a vehicle according to the present invention.
It is a figure showing an example.

FIG. 2 is a sectional view showing an example of a conventional closed center type brake booster used in the present invention.

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

FIG. 4 is a diagram showing an example of a conventional vehicle hydraulic boosting system.

FIG. 5 is a cross-sectional view showing an example of a conventional open center type hydraulic brake booster.

[Explanation of symbols]

1 ... Hydraulic boosting system for vehicle, 2 ... Brake pedal, 3
… Open center type hydraulic brake booster,
4 ... Master cylinder, 5 ... Brake cylinder, 6 ... Handle, 7 ... Open center type power steering device, 8 ... Pump, 10 ... Reservoir, 28 ... Closed center type hydraulic brake booster, 29 ... Brake side supply passage, 30 ... check valve, 31 ... accumulator, 32 ... pressure switch, 33 ... power steering side supply passage (PS side supply passage), 34 ... flow rate limiting valve,
34a ... Orifice, 35 ... Electronic control unit (ECU),
36 ... Brake switch, 37 ... Handle switch, 3
8 ... Input shaft, 39 ... Control valve, 40 ... Power chamber, 41, 42,
43,44,45,46,49,50,51,52 ... Passage, 4
7 ... power piston, 48 ... output shaft, 53 ... discharge passage,
54 ... Bypass passage, 55 ... Second pump, 56 ... Motor, 57 ... Check valve

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[Procedure amendment]

[Submission date] October 3, 1995

[Procedure Amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

[Fig. 2]

[Figure 3]

FIG. 4

[Figure 5]

Claims (3)

[Claims] 1. A reservoir for storing a hydraulic fluid, a first pump for sucking and discharging the hydraulic fluid in the reservoir,
The accumulator which stores the hydraulic pressure of the hydraulic fluid discharged from the first pump, the first operating member, and the first control valve which is normally closed are opened by the operation of the first operating member to open the first hydraulic pressure of the accumulator. Is introduced into the power chamber and acts on the first power piston, so that the operating force of the first operating member is boosted by the first hydraulic pressure from the accumulator and is output. The force device, the second operating member, and the hydraulic fluid normally discharged from the first pump freely flow through the gap of the second control valve provided inside to recirculate to the reservoir, When the second operation valve is operated, the hydraulic fluid generates a second hydraulic pressure by narrowing the gap of the second control valve, and the second hydraulic pressure acts on the second power piston provided inside, The second operation unit A second hydraulic booster of the open center type for boosting and outputting the operating force of the second hydraulic pressure and the hydraulic fluid discharged from the first pump to the second hydraulic booster. A flow restricting position provided in a supply passage for restricting the flow rate of the hydraulic fluid flowing through the supply passage during normal operation and being switched to a non-limiting position where the flow rate of the hydraulic fluid flowing through the supply passage is not restricted during normal operation. A flow rate limiting valve, a pressure detecting means that is turned on when the hydraulic pressure of the accumulator is a predetermined value or less to output a hydraulic pressure drop detection signal, and a brake operating signal that is turned on when a brake operation is performed. Brake operation detecting means for outputting,
Steering operation detecting means that is turned on to output a steering operation signal when a steering operation is performed, and the flow rate limiting valve is set to the unlimited flow rate position when the hydraulic pressure decrease detection signal is not output from the pressure detecting means. When the fluid pressure drop detection signal is output together with the flow rate limiting valve is set to the flow rate limiting position, and when the flow rate limiting valve is set to the flow rate limiting position, the brake operation detection Control for switching the flow rate limiting valve so as to set the flow rate limiting valve to the flow rate unlimited position only when the steering operation signal is output from the steering operation detecting means without outputting the brake operation signal from the means. And a hydraulic boosting system for a vehicle. 2. A reservoir for storing the working fluid, and a first pump for sucking and discharging the working fluid in the reservoir,
The accumulator which stores the hydraulic pressure of the hydraulic fluid discharged from the first pump, the first operating member, and the first control valve which is normally closed are opened by the operation of the first operating member to open the first hydraulic pressure of the accumulator. And a closed center type first hydraulic booster that boosts the operating force of the first operating member by the first hydraulic pressure from the accumulator and outputs it by acting on the first power piston. The second operating member and the hydraulic fluid normally discharged from the first pump are allowed to freely flow through the gap between the second control valve provided inside and recirculate to the reservoir, and the second operating member When the second control valve is closed during the operation of, the hydraulic fluid generates a second hydraulic pressure and the second hydraulic pressure acts on a second power piston provided inside the second control valve. Operation of operation members And open center type second fluid pressure booster and outputs the boosted by the second fluid pressure, said first
It is provided in a supply passage for supplying the hydraulic fluid discharged from the pump to the second hydraulic booster, and is normally set at a flow rate unlimited position that does not limit the flow rate of the hydraulic fluid flowing through this supply passage. A flow rate limiting valve that is switched at a time to be set to a flow rate limiting position that limits the flow rate of the hydraulic fluid in the supply passage, the reservoir and the first hydraulic booster are connected by bypassing the first pump. A second pump provided in the bypass passage, a pressure detecting unit that is turned on when the hydraulic pressure of the accumulator is equal to or less than a predetermined value, and outputs a hydraulic pressure drop detection signal, and is turned on when a brake operation is performed to brake. A brake operation detecting means for outputting an operation signal, a steering operation detecting means for turning on when a steering operation is performed and outputting a steering operation signal,
When the hydraulic pressure drop detection signal is not output from the pressure detection means, the flow rate limiting valve is set to the flow rate unlimited position, and when the hydraulic pressure drop detection signal is output, the flow rate limiting valve is set to the flow rate limiting position. When the flow rate limiting valve is set to the flow rate limiting position and a steering operation signal is output from the steering operation detecting means, the flow rate limiting valve is set to the flow rate unlimited position. In addition, when the flow rate limiting valve is set to the flow rate limiting position, when the steering operation signal is output from the steering operation detecting means and the brake operation signal is output from the brake operation detecting means, the flow rate is The flow restricting valve and the front so as to set the restricting valve to the flow restricting position and drive the second pump. Vehicle hydraulic boosting system characterized by comprising a control device for operation control of the second pump. 3. The first operating member is a brake operating member, the first hydraulic pressure booster is a hydraulic brake booster, the second operating member is a steering wheel, and the second hydraulic pressure multiplier is used. The hydraulic boosting system for a vehicle according to claim 1 or 2, wherein the force device is a power steering device.