JPS61184154A - Brake device for vehicle - Google Patents

Abstract

PURPOSE:To obtain a stable braking condition at all times by controlling an electric hydraulic control valve in accordance with deviation of actual car speed from an ideal car speed in which deceleration is carried out at a decelerating rate corresponding to an output signal of a brake operating force detecting device from the car speed at the start of braking. CONSTITUTION:An electric hydraulic control valve C which can shift the hydraulic pressure of a brake cylinder B to a pressure-rising allowable condition and a pressure- lowering allowable condition, is provided in a liquid passage connecting a hydraulic pressure source A to a brake cylinder B. An ideal car speed determining means G for obtaining an ideal car speed in which deceleration is carried out at a decelerating rate corresponding to a brake operating force, from the car speed at the start of braking which is indicated by an actual car speed from a car speed detecting device F at the start of braking operation which is detected by an operating force detecting device E attached to a brake operating member D, is provided. And, the ideal car speed is compared with an actual car speed by a comparing means H to output a signal for shifting said control valve C to a pressure-lowering allowable condition when the ideal car speed is greater, or a signal for shifting the valve C to a pressure- rising allowable condition when the actual car speed is greater.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a brake device for a vehicle, and in particular to an ideal brake device that responds to the operating force of a brake operating member regardless of changes in conditions such as the vehicle load and the friction coefficient of the brake friction material. The present invention relates to a brake device that can brake a vehicle according to a typical deceleration characteristic.

(Prior Art) A vehicle brake device generally brakes a vehicle by supplying hydraulic pressure to a brake cylinder of a brake that suppresses rotation of a wheel in response to the operation of a brake operating member. Conventionally, in such brake devices, hydraulic pressure is supplied to the brake cylinder at a level corresponding to the operating force of the brake operating member, regardless of changes in conditions such as the load and the coefficient of friction of the brake friction material. was.

(Problems to be Solved by the Invention) Therefore, with conventional brake devices, there are cases where the vehicle cannot be decelerated or stopped as expected by the driver. When braking a vehicle, the driver determines the necessary braking force based on experience from various information such as the traveling speed at the time of braking, the target speed at which to decelerate, or the target position at which to stop. It is normal to operate the brake operating member using the operating force that is expected to generate power, but this operation is performed based on certain judgment criteria that the driver has acquired under normal conditions. , when the load is large and the inertia of the vehicle is larger than normal, or when the friction coefficient of the brake friction material is usually smaller due to an increase in temperature, the necessary deceleration may be reduced. If a greater operating force than under normal conditions is required to achieve this, the braking force may be insufficient and the driver may feel uncomfortable. On the other hand, if the live load is particularly small or the friction coefficient of the brake friction material is larger than normal, the braking force may be applied more than expected, giving the driver a sense of discomfort.

(Means for Solving the Problems) In order to solve the above problems, the present applicant has developed a vehicle brake system as described above, which meets conditions such as the vehicle load and the friction coefficient of the brake friction material. We have developed a device that can stably brake a vehicle according to ideal deceleration characteristics corresponding to the operating force applied to the brake operating member even when the brake operating force changes, and filed an application as Japanese Patent Application No. 59-231153. This application is a related application, and the brake device according to the first invention is provided in a fluid passage connecting a FAL fluid pressure source and a brake cylinder, as shown in the claim correspondence diagram of FIG. An electric fluid that can be controlled to at least switch between a pressure increase permissible state in which the hydraulic pressure of the brake cylinder is allowed to be increased by the hydraulic pressure of a hydraulic pressure source and a pressure drop permissible state in which the brake cylinder hydraulic pressure is permitted to decrease. a pressure control valve, a vehicle speed detection device that outputs an actual vehicle speed signal corresponding to the actual vehicle speed of the BL vehicle, and an operating force detection device that outputs an operating force signal corresponding to the operating force applied to the Cl brake operating member. , (d) decelerate from the vehicle speed at the start of braking represented by the actual vehicle speed signal from the vehicle speed detecting device at the time of starting the operation of the brake operating member at a deceleration corresponding to the operating force represented by the operating force signal from the operating force detecting device. An ideal vehicle speed determination means for determining the ideal vehicle speed compares the ideal vehicle speed determined by the ideal vehicle speed determination means with the actual vehicle speed represented by the actual vehicle speed signal from the vehicle speed detection device, and if the ideal vehicle speed is large, the Comparing means outputs a pressure reduction signal to switch the electrohydraulic pressure control valve to the pressure drop permissible state, and outputs a pressure increase signal to switch the electrohydraulic pressure control valve to the pressure increase permissible state when the actual vehicle speed is high.

Note that the ideal vehicle speed determining means and the comparing means may be constructed by a computer or by a discrete circuit, but when they are constructed by a discrete circuit, the ideal vehicle speed determining means is A hold circuit that holds the actual vehicle speed signal from the device indicating the vehicle speed at the start of braking, and outputs an operating force-related signal that increases as time passes, and the increment increases as the operating force signal from the operating force detection device increases. and an ideal vehicle speed signal generation circuit that subtracts the operating force-related signal from the operating force-related signal generation circuit from the actual vehicle speed signal held by the hold circuit and outputs an ideal vehicle speed signal. At the same time, the comparison means compares the ideal vehicle speed signal from the ideal vehicle speed signal generation circuit and the actual vehicle speed signal from the vehicle speed detection device, outputs a decompression signal when the ideal vehicle speed signal is large, and outputs a decompression signal when the actual vehicle speed signal is large. It is preferable that the converter includes a comparison circuit that outputs a pressure-increasing signal.

In addition, as shown in the claim correspondence diagram of FIG. 2, the brake device according to the second invention eliminates (e) the comparison means of the first invention and newly incorporates (f) a feature corresponding to the hydraulic pressure of the brake cylinder. (g) a hydraulic pressure detection device that outputs a hydraulic pressure signal;
The ideal vehicle speed determined by the ideal vehicle speed determination means is compared with the actual vehicle speed represented by the actual vehicle speed signal from the vehicle speed detection device in the region where the vehicle speed is above a certain value, and if the ideal vehicle speed is high, the electro-hydraulic control valve is activated. (h
1. In a region where the vehicle speed is lower than the certain value, the ideal hydraulic pressure of the brake cylinder corresponding to the operating force signal from the operating force detecting device is determined, and the ideal hydraulic pressure and the hydraulic pressure signal from the hydraulic pressure detecting device are a second comparison means that compares the expressed actual hydraulic pressure and outputs the pressure reduction signal to the electrohydraulic control valve when the actual hydraulic pressure is high, and outputs the pressure increase signal when the ideal hydraulic pressure is high; It is said that the configuration includes the following.

(Operation and Effect) In the brake device according to the first invention, the hydraulic pressure in the brake cylinder of the brake decreases when a pressure reduction signal is output from the comparing means to the electrohydraulic pressure control valve, and a pressure increase signal is output. and rise. Then, the comparison means outputs a pressure reduction signal and a pressure increase signal so that the actual vehicle speed of the vehicle matches the ideal vehicle speed determined by the ideal vehicle speed determination means. Also,
The ideal vehicle speed determining means determines an ideal vehicle speed at which the vehicle speed at the start is decelerated at a deceleration corresponding to the operating force based on the vehicle speed at the start of braking and the operating force applied to the brake operating member when the operation of the brake operating member is started. .

In other words, according to the brake device according to the first invention, the operating force of the brake operating member is always equal to the vehicle speed at the time when the operation of the brake operating member is started, regardless of changes in conditions such as the load and the coefficient of friction of the brake friction material. The vehicle is decelerated at a deceleration rate corresponding to . Therefore, even if you operate the brake operating member in a normal manner, you will not be able to obtain the expected braking force due to unusual conditions, or you will not receive more braking force than expected. This makes it possible to brake the vehicle in a stable manner at all times.

Further, in the brake device according to the second invention, the electro-hydraulic control valve is switched and controlled by the signal output from the first comparing means similar to the comparing means of the first invention in a region where the vehicle speed is above a certain value. Therefore, as in the first invention, the vehicle can always be decelerated at a deceleration according to the operating force of the brake operating member regardless of changes in conditions. Since the control valve is controlled by the signal output from the second comparing means and the hydraulic pressure of the brake cylinder is controlled to a value corresponding to the operating force of the brake operating member, the vehicle is in a stopped state or In a state close to that, there is an advantage that the braking force of the vehicle can be stably maintained at the level desired by the driver.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 3, 10 is a brake pedal as a brake operating member. This brake pedal 10 has a detection rod 14 equipped with a load cell 12 which is an operating force detection device.
are connected to each other, and the load cell 12 is connected to the spring 1.
Supported by 5. Therefore, when a depressing force is applied to the brake pedal 10 as an operating force, the brake pedal 10 is allowed to rotate within a certain angle range, and the depressing force is detected by the load cell 12, and a depressing force signal SF corresponding to the magnitude is sent to the strain amplifier 16. The signal is amplified and supplied to the main controller 18. Further, a brake switch 20 is provided near the brake pedal 10 to detect whether or not the brake pedal 10 is depressed.
When the brake switch 20 is depressed, a brake operation signal SB is supplied from the brake switch 20 to the main control device 18. This brake operation signal SB is also supplied to the stop lamp 22, which lights up to indicate that the brake pedal 10 has been depressed.

Further, in FIG. 3, 38 is a front wheel, and 40 is a rear wheel. The front wheels 38.38 and the rear wheels 40.40 are provided with brakes having brake cylinders 42.42 and 44.44, respectively, and these brakes suppress the rotation of each wheel and brake the vehicle. There is. A fluid pressure sensor 48, which is a fluid pressure detection device, is provided in the fluid passage 46 connected to the brake cylinder 42, and the fluid pressure inside the brake cylinder 42 is detected by this fluid pressure sensor 48. After the hydraulic pressure signal SP representing the generated hydraulic pressure is amplified by the strain amplifier 50, the main controller 18
supplied to On the other hand, a proportioning valve 52 is provided in the fluid passage 51 connected to the brake cylinder 44, and after the fluid pressure supplied through the fluid passage 54 exceeds a set value, the fluid pressure is reduced at a fixed ratio. and is supplied to the brake cylinder 44.

The liquid passage 54 is a three-way switching valve 5 which is an electrohydraulic pressure control valve.
6. The three-way switching valve 56 is connected to a pump 6o, which is a hydraulic pressure source, through a liquid passage 58, and
The drain passage 62 is connected to the reservoir tank 64, and the liquid passage 5
4 is communicated with the liquid passage 58 to supply the hydraulic pressure pressurized by the pump 6o to the brake cylinder 42.44. It is possible to switch between a pressure drop permitting state in which the brake fluid is discharged into the reservoir tank 64 and a hydraulic pressure holding state in which communication between the fluid passages is cut off and the hydraulic pressure in the brake cylinders 42, 44 is maintained. Further, the pump 60 is driven by a motor 68 to supply the brake fluid pumped up from the reservoir tank 64 to the accumulator 70 through the fluid passage 58, and accumulates it at a constant fluid pressure. Note that the motor 68 drives the pump 60 while the relay 72 is being driven by the relay drive signal SR from the main controller 18.

Further, each of the front wheels 38 and 38 is provided with a rotation sensor 74 which is a vehicle speed detection device, and the rotation signal of a frequency corresponding to the rotation speed of each wheel outputted from each rotation sensor 74 is converted into a frequency/voltage. (hereinafter simply referred to as F/V)
The signal is converted into an actual vehicle speed signal SV having a voltage corresponding to the actual vehicle speed by a converter (referred to as a converter) 75, and is supplied to the main controller 18. Note that the actual vehicle speed signal S■ corresponds to the average value of the rotation signals from each rotation sensor 74.

The main controller 18 has a configuration as shown in FIG. In FIG. 4, 76 is a differential amplifier, and the pedal force signal SF from the strain amplifier 16 is amplified by the differential amplifier 76 and then supplied to the staircase wave generation circuit 80 via an analog switch 78. It is directly supplied to the hydraulic pressure conversion amplifier 82. A pulse control signal from the oscillation circuit 90 whose frequency has been divided by the frequency dividers 84 and 86 and amplified by the buffer amplifier 88 is input to the control terminal of the analog switch 78 .
0 is supplied with the output signal of the differential amplifier 76 at regular intervals.

The staircase wave generation circuit 80 includes a relay 92, and operates only while the relay 92 is driven. Then, from the time when the relay 92 starts to be driven, as shown in FIG. 5, the level is stepped up at the cycle of the signal supplied via the analog switch 78 and according to the magnitude of the signal. A staircase wave signal is output, and the staircase wave signal is supplied to a subtraction circuit 94. Further, the relay 92 is driven only while the relay drive signal is output from the control signal generator 96, and the control signal generator 96 receives the brake operation signal S.
While B is being input, a relay drive signal is output. In other words, the staircase wave generation circuit 80 generates a waveform when the brake pedal 10 is depressed.
A staircase wave signal that increases at a steeper slope as the pedal force applied to the pedal increases is output to the subtraction circuit 94.

On the other hand, the subtraction circuit 94 is supplied with an actual vehicle speed signal corresponding to the actual vehicle speed at the time when the brake pedal 10 is started to be depressed (hereinafter, this vehicle speed will be referred to as the vehicle speed at the start of braking). That is, the actual vehicle speed signal SV from the F/V converter 75 is amplified by the vehicle speed amplifier 98 and supplied to the sample and hold circuit 100.
0, the signal is held by a sampling signal output from the control signal generator 96 at the same time as the start of depression of the brake pedal 10, and the vehicle speed signal at the start of braking held by this sample hold circuit 100 is held by the amplifier. The signal is amplified by step 102 and supplied to subtraction circuit 94. And subtraction circuit 9
4, the staircase wave signal is subtracted from the vehicle speed signal at the start of braking from the amplifier 102, as shown in FIG.
A staircase wave signal that reaches a maximum level corresponding to the vehicle speed at the start of braking when the brake pedal 10 is depressed, and the level steps down at a gradient corresponding to the magnitude of the pedal force applied to the brake pedal 10 as time passes. is output, and this staircase wave signal is supplied to comparison circuits 106 and 108 via analog switch 104. The staircase wave signal outputted from the subtraction circuit 94 is associated in advance with the amplification factors of the strain amplifier 6 and the differential amplifier 76, as well as the period of the pulse control signal supplied to the control terminal of the analog switch 78. By setting the gradient to correspond to the ideal deceleration of the vehicle depending on the magnitude of the pedal force, the level of the staircase wave signal is set to correspond to the ideal vehicle speed of the vehicle at each point in time. It is designed to correspond to

That is, in this embodiment, the subtraction circuit 94 constitutes an ideal vehicle speed signal generation circuit, and as is clear from the above description, the staircase wave generation circuit 80 constitutes an operating force related signal generation circuit. There is.

, furthermore, the subtraction circuit 941 and the staircase wave generation circuit 80,
The sample and hold circuit 100 and the like constitute ideal vehicle speed determining means.

The comparison circuits 106 and 108 also include the vehicle speed amplifier 98.
The actual vehicle speed signal SV representing the actual vehicle speed is supplied from the analog switch 110 through the analog switch 110, and the actual vehicle speed signal SV is compared with the staircase wave signal from the subtraction circuit 94, that is, the ideal vehicle speed signal in the comparison circuits 106 and 108. It has become. Then, in the comparison circuit 106, the actual vehicle speed signal SV
When the ideal vehicle speed is greater, a pressure increase permission signal representing this is output, and when the ideal vehicle speed is larger, a pressure reduction permission signal is outputted from the comparison circuit 108, and these signals are supplied to the timing controller 112. It has become.

The timing controller 112 includes the oscillation circuit 90
and is frequency-divided by frequency divider circuits 84 and 114,
A timing signal with a duty ratio set is supplied to the integrating circuit 116 and the comparison circuit 118, and when a pressure increase permission signal is supplied from the comparison circuit 106, a pressure increase-holding signal corresponding to the timing signal is supplied. However, when the pressure reduction permission signal is supplied from the comparator circuit 108, pressure reduction-holding signals are outputted and supplied to the constant current controller 120, respectively. That is, the timing controller 112 outputs the pressure increase signal while the timing signal is at a high level when the pressure increase permission signal is input, and outputs the pressure reduction signal by the amount at which the timing signal is at the high level when the pressure decrease permission signal is input. At other times, hydraulic pressure holding signals are output and these signals are supplied to the constant current controller 120.

Although not shown, the comparison circuit 118 is capable of adjusting the comparison value, thereby making it possible to set the duty ratio of the timing signal to a desired value.

The constant current controller 120 maintains the excitation signal SC, that is, the drive current of the power transistor 122 that excites the solenoid 66 of the three-way switching valve 56, at a constant value according to the hexagonal signal from the timing controller 112. When a pressure increase signal is input, no drive current is applied to the solenoid 66 and the three-way switching valve 56 is kept in a pressure increase permissible state, but when a hydraulic pressure maintenance signal is input, a drive current of, for example, 2.5 A is applied. Flow three-way valve 5
6 is switched to a hydraulic pressure holding signal, and when a pressure reduction signal is input, a drive current of 5 A is applied to switch the three-way switching valve 56 to a pressure reduction permissible state. By switching control of the three-way switching valve 56, the brake cylinder 42.
44 is controlled so that the actual vehicle speed of the vehicle matches the ideal vehicle speed represented by the ideal vehicle speed signal from the subtraction circuit 94, that is, the vehicle speed that decelerates at an ideal deceleration according to the depression force of the brake pedal 10. As a result, the vehicle is always braked with ideal deceleration characteristics corresponding to the pedal force applied to the brake pedal 10, regardless of changes in conditions such as the load and the coefficient of friction of the brake friction material. This makes it possible. As is clear from the above description, in this embodiment, the comparison circuit 106. A comparison circuit corresponding to the comparison means of the first invention is composed of the LO 8, the timing controller 112, and the like. In addition, 124 in the figure
is the feedbank resistance.

Incidentally, a signal output from the comparison circuit 126 is input to the control terminals of the analog switches 104 and 110. This comparison circuit 126 compares the actual vehicle speed signal SV from the vehicle speed amplifier 98 with a preset threshold value corresponding to a constant low speed, and outputs the actual vehicle speed signal S
is larger than the threshold value, a high level signal is output, and this high level signal is directly supplied to analog switches 104 and 110. When the signal from the comparator circuit 126 is at a high level, the analog switches 104 and 110 prevent passage of the ideal vehicle speed signal output from the subtraction circuit 94 and the actual vehicle speed signal SV output from the vehicle speed amplifier 98, as described above. It is now allowed. That is, in this embodiment, the vehicle is decelerated at an ideal deceleration corresponding to the ideal vehicle speed in a region where the vehicle speed is equal to or higher than the certain low speed. The first comparison means of the second invention is also constituted by a comparison circuit similar to the comparison means of the first invention.

On the other hand, when the pedal force signal SF supplied to the hydraulic pressure conversion amplifier 82 is supplied to the comparison circuits 106 and 108 via the analog switch 128, the differential amplifier 13
The hydraulic pressure signal S from the strain amplifier 50 amplified by 0
P is supplied via an analog switch 132. The hydraulic pressure conversion amplifier 82 is configured to amplify the pedal force signal SF to an ideal hydraulic pressure signal having the same magnitude as the hydraulic pressure signal output from the differential amplifier 130. Further, the output signal of the comparison circuit 126 is inverted by an inverter 134 and supplied to the control terminals of the analog switches 128 and 132, so that the actual speed of the vehicle is lower than the constant low speed. Only when the ideal hydraulic pressure signal which is the output signal of the hydraulic pressure conversion amplifier 82 and the differential amplifier 130
The actual hydraulic pressure signal which is the output signal of the comparator circuits 106 and 10
8. And comparison circuit 1
From 06 onwards, as in the case of comparing the ideal vehicle speed signal and the actual vehicle speed signal, a pressure increase permission signal is output when the ideal hydraulic pressure signal is larger, and the comparison circuit 108 outputs a pressure increase permission signal when the ideal hydraulic pressure signal is larger. When the pressure increase permission signal and the pressure reduction permission signal are large, a pressure reduction permission signal is outputted and supplied to the timing controller 112, respectively, and the three-way switching valve 56 is controlled to switch in accordance with the pressure increase permission signal and the pressure reduction permission signal, as described above. ing. That is, when the vehicle speed is below the predetermined low speed, the hydraulic pressure in the brake cylinders 42, 44 is lower than the brake pedal 10.
Therefore, when the vehicle is at or near a standstill, the braking force of the vehicle can be stably maintained at the level desired by the driver. As is clear from the above description, in this embodiment, the second comparing means of the second invention is constituted by the same comparing circuit as the first comparing means, although the comparison target is different.

Further, when the depression operation of the brake pedal 10 is released, the timing controller 112 is supplied with a pressure reduction instruction signal from the control signal generator 96 for a certain period of time, and the timing controller 112 receives this pressure reduction instruction signal. constant current controller 120 supplied with
A pressure reduction signal is continuously supplied to the three-way switching valve 56 to maintain the pressure reduction permission state, and the hydraulic pressure in the brake cylinders 42 and 44 is released. In addition, the timing controller 11
2 supplies a hydraulic pressure holding signal to the constant current controller 120 after the supply of this pressure reduction instruction signal is stopped, and maintains the three-way switching valve 56 in the hydraulic pressure holding state until the next pedal force is applied to the brake pedal 10. It has become.

Further, a relay drive signal SR supplied to the motor drive relay 72 is output from a control signal generator 96. This relay drive signal SR is issued at the same time as the brake pedal 10 is depressed, and is stopped after a certain period of time, for example, 3 seconds, has elapsed after the output of the pressure reduction instruction signal is stopped. As a result, the fluid pressure in the fluid passage 58 is maintained at a high pressure while the brake pedal IO is being depressed, and the accumulator trough is 0 after the brake pedal 10 is released.
High hydraulic pressure is accumulated in the brake cylinders 42 and 44 so that hydraulic pressure can be immediately supplied to the brake cylinders 42 and 44 at the time of the next brake operation.

In such a brake device, when the brake pedal 10 is depressed while the vehicle is running, the brake pedal 20
is closed, and the brake operation signal SB is turned on to stop lamp 2.
2 to turn on the light, and is also supplied to the control signal generator 96. As a result, the control signal generator 96
A sampling signal is supplied to the sample hold circuit 100, and an actual vehicle speed signal SV corresponding to the vehicle speed at that time is obtained.
is held, and the brake start vehicle speed signal, which is the held actual vehicle speed signal SV, is supplied to the subtraction circuit 94. On the other hand, at the same time as the sampling signal is generated, a relay drive signal is supplied from the control signal generator 96 to the relay 92 of the staircase wave generation circuit 80, and as a result, the gradient increases from the staircase wave generation circuit 80 at a gradient corresponding to the depression force of the brake pedal 10. A staircase signal is generated and supplied to subtraction circuit 94. Then, in the subtraction circuit 94, based on the vehicle speed signal at the start of braking and the staircase wave signal, an ideal vehicle speed signal representing the ideal vehicle speed at which the vehicle speed at the start of braking is decelerated at a deceleration according to the depression force of the brake pedal 10 is obtained, Comparison circuit 106
, 108. Further, at the same time as the brake pedal 10 is depressed, a relay drive signal S is sent from the control signal generator 96.
R is output, and driving of the pump 60 is started.

The comparison circuits 106 and 108 compare the ideal vehicle speed signal from the subtraction circuit 94 with the actual vehicle speed signal SV representing the actual vehicle speed detected by the rotation sensor 74, and send a pressure increase permission signal to the timing controller 112 according to the comparison result. and a depressurization permission signal is provided. Then, the three-way switching valve 56 is controlled to switch according to the pressure increase signal, pressure decrease signal, and hydraulic pressure holding signal outputted from the timing controller 112 in accordance with the pressure increase permission signal and pressure decrease permission signal, and the three-way switching valve 56 is controlled to switch. Hydraulic pressure is increased. As a result, the vehicle changes from the vehicle speed at the start of braking to the brake pedal 1.
The vehicle is decelerated at an ideal deceleration corresponding to the applied pedal force.

When the actual vehicle speed becomes smaller than a preset constant low speed, the output of the comparison circuit 126 is inverted. As a result, the comparison circuits 106 and 108 receive an actual hydraulic pressure signal representing the hydraulic pressure in the brake cylinders 42 and 44 detected by the hydraulic pressure sensor 46, and an ideal hydraulic pressure signal which is the output signal of the hydraulic pressure amplifier 82. After that, based on a comparison between the actual hydraulic pressure signal and the ideal hydraulic pressure signal, the hydraulic pressure in the brake cylinders 42 and 44 becomes a hydraulic pressure corresponding to the magnitude of the pedal force applied to the brake pedal 10. Thus, the three-way switching valve 56 is controlled to switch.

The pressing force applied to the brake pedal 10 is eliminated,
When the brake is released, a pressure reduction instruction signal is output from the control signal generator 96 to the timing controller 112.
Based on the pressure reduction instruction signal, the three-way switching valve 56 is maintained in a pressure reduction permissible state for a certain period of time, and the brake cylinder 42.4
The hydraulic pressure inside 4 is eliminated. Then, after the hydraulic pressure is eliminated, the three-way switching valve 56 is switched to a hydraulic pressure holding state, and after a certain period of time has elapsed, the drive of the pump 60 is stopped.

In the embodiment described in detail above, the pump 60, which is the hydraulic pressure source, is directly connected to the brake cylinder 42, 44 through the hydraulic passages 58, 54, 46, and 51. Although a three-way switching valve 56 is provided as a control valve, it is also possible to connect the pump 60 indirectly to the brake cylinder 42, 44 via a mask cylinder 140 as shown in FIG. below,
Regarding this embodiment, only the points different from the previous embodiment will be explained.

The mask cylinder 140 has pistons 144 and 146 arranged in series within a housing 142 to form three hydraulic chambers 14.
8.150 and 152 are formed, and the liquid passage 54 from the three-way switching valve 56 is connected to the liquid pressure chamber 148, while the liquid pressure chambers 150 and 152 are connected to the liquid passage 51 and 46, respectively. brake cylinder 44
and 42.

Pistons 144 and 146 each have a spring 15
4 and 156 in the backward direction (to the right in FIG. 7), and the liquid passage 58. When hydraulic pressure is supplied to the hydraulic chamber 148 via the three-way switching valve 56 and the hydraulic passage 54 (see FIG. 3), the pistons 144 and 146 move forward, and the hydraulic chamber 1 is supplied to the hydraulic chambers 150 and 152.
48, which is supplied to the brake cylinders 44 and 42. In addition, 1
Reservoir chambers 58 and 160 communicate with a reservoir (not shown) through reservoir ports 162 and 164, respectively.

A spring 15 that applies an appropriate reaction force to the brake pedal 1o is disposed in a housing 170 that is integrally formed with the housing 142 of the mask cylinder 140. However, in this embodiment, the spring 15 does not act directly on the load cell 12 as in the previous embodiment, but instead acts on the two pistons 172 and 17.
4 and the brake fluid in the hydraulic pressure chamber 176 interposed between both pistons.

That is, although the piston 172 is urged in the backward direction by the spring 178 and the hydraulic pressure chamber 176 is filled with brake fluid, this hydraulic pressure chamber 176 and the reservoir chamber 1
58 is always connected to the cut valve 182.
Therefore, the brake fluid in the hydraulic pressure chamber 176 functions as if it were solid, and transmits the elastic force of the spring 15 to the load cell 12.

The cut valve 182 includes a valve element 186 that is slidably fitted into a housing 184 that is integral with the housing 142 of the mask cylinder 140 .

Valve 186 is normally maintained in the operative position shown in FIG. 7 by spring 188, in which it cooperates with cup seal 190 to block liquid passage 180. The hydraulic pressure of the hydraulic pressure chamber 176 acts on the valve element 186 to try to move it back from the operating position, but the hydraulic pressure chamber 192 formed behind the valve element 186 has a liquid passage 19.
Since the hydraulic pressure in the hydraulic pressure chamber 148 is guided through 4,
Pump 60. When the three-way switching valve 56 and the like are operating normally, the valve element 186 is not moved back from the operating position.

However, pump 60. If a failure occurs in the three-way switching valve 56 or its control device and hydraulic pressure no longer acts on the hydraulic pressure chamber 148, the valve element 186 will move into its annular groove 195.
is retracted to a position corresponding to the cup seal 190, the sealing function of the cup seal 190 is lost, and the liquid passage 1
80 is in a non-blocking state. Therefore, the brake fluid in the hydraulic pressure chamber 176 is transferred to the fluid passage 180. It can flow out to a reservoir (not shown) through the reservoir chamber 158 and the reservoir port 162, and the piston 172 is in a state where it can freely move relative to the piston 174.

That is, the brake pedal 10 is not subjected to the elastic force of the spring 15, but the brake pedal 10 has a bushing rod 1 in addition to the detection rod 14.
96 are connected to each other so that the depression force applied to the brake pedal 10 is transmitted to the mask cylinder 140 via this bushing rod 196. The bushing rod 196 is connected to the piston 14 of the mask cylinder 140.
4 does not act on the piston 144 when it is operated by the hydraulic pressure in the hydraulic chamber 148;
If the bushing rod 196 is moved forward by a certain distance or more with no hydraulic pressure being applied to the bushing rod 8 and the piston 144 is kept in the retreated position, the large diameter portion 198 provided on the bushing rod 196 comes into contact with the piston 144 and brakes. The force applied to the pedal 10 is transmitted to the piston 144.

As is clear from the above description, in this embodiment, the hydraulic pressure generated in the pump 60 and controlled by the three-way switching valve 56 is supplied to the mask cylinder 140,
Here, the hydraulic pressure is divided into two independent systems and supplied to the brake cylinders 42 and 44, respectively. Therefore, even if either system of brake cylinders 42, 44 is damaged, the other system's brakes will operate normally and the vehicle can be stopped.

Also, the pump 60. If a failure occurs in the three-way switching valve 56 and its control system, the pedal force applied to the brake pedal 10 is mechanically transmitted to the mask cylinder 140 via the bushing rod 196, causing fluid to flow into the hydraulic chambers 150 and 152. Since pressure is generated, the vehicle can be stopped without any problem even in the event of a failure in the control system.

Further, in the state where the mask cylinder 140 is directly actuated by the depression force of the brake pedal 10 as described above, the brake fluid in the hydraulic pressure chamber 176 can freely flow out to the reservoir, so that the spring 15 No elastic force acts on the brake pedal 10, and the pedal force applied to the brake pedal 10 is effectively used to operate the brake.

Although two embodiments of the present invention have been described above, these are literally illustrative, and the present invention should not be interpreted as being limited to the above specific examples.

For example, although the brake devices of the above two embodiments are not provided with an anti-skid function, the front wheels 38 and the rear wheels 4
A means for detecting a slip ratio of 0 is provided, and the main controller 18
If the three-way switching valve 56 is provided with a function of switching the three-way switching valve 56 so that the slip ratio is within an appropriate range, it becomes possible to prevent the occurrence of skids. In this case, if the three-way switching valve 56 is provided between the mask cylinder 140 and the brake cylinders 142 and 144 in FIG.
It becomes possible to independently prevent skids between the rear wheels 40 and the rear wheels 40.

Further, in the embodiment, the comparison between the ideal vehicle speed signal and the actual vehicle speed signal and the comparison between the ideal hydraulic pressure signal and the actual hydraulic pressure signal are simultaneously performed in the two comparison circuits 106 and 108, respectively, and depending on the comparison results, In this case, one comparison circuit 106 outputs a pressure increase permission signal, and the other comparison circuit 108 outputs a pressure reduction permission signal.
- It is also possible to perform K using only one comparison circuit and output a pressure increase permission signal and a pressure reduction permission signal according to the comparison result. Further, the comparison circuits 106 and 108 may directly output a pressure increase signal and a pressure decrease signal instead of the pressure increase permission signal and the pressure decrease permission signal.

Furthermore, hysteresis is added to the comparison values in the comparison circuits 106 and 108 so that the ideal vehicle speed and ideal hydraulic pressure have a certain width, and the values in the brake cylinders 42 and 44 are adjusted according to the ideal vehicle speed and fluid pressure having the certain width. The hydraulic pressure may also be controlled.

Further, in the above embodiment, the operating force related signal generation circuit is the staircase wave generation circuit 80, and the staircase wave signal is generated as the operating force related signal. It is also possible to make the operating force related signal into a ramp signal that linearly increases over time. In this case, the ideal vehicle speed signal output from the subtraction circuit 94 also becomes a signal that decreases linearly with the passage of time.

In addition, in the above embodiment, the load cell 1 is included in the operating force detection device.
2 was adopted, but it is possible to adopt various operating force detection devices depending on the situation and purpose, such as a device that detects the amount of rotation of the brake pedal 10 to detect the magnitude of the pedal force. . It is also possible to detect the depression state of the brake pedal 10 from the output of the operating force detection device and supply this to the control signal generator 96 as a brake operating signal.

Further, in the embodiment described above, the main control device 18 was entirely constructed of discrete circuits, but it is also possible to construct part or all of the portion surrounded by dotted lines in FIG. 4 by a computer.

Although not listed here, it goes without saying that the present invention can be practiced with various modifications and improvements without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are claim correspondence diagrams showing the first invention and the second invention, respectively. FIG. 3 is a system diagram showing an entire embodiment common to the first invention and the second invention,
FIG. 4 is a block diagram showing the main control device of FIG. 3. 5 and 6 are waveform diagrams for explaining output signals of the staircase wave generation circuit and subtraction circuit of FIG. 4. FIG. FIG. 7 is a front sectional view showing a mask cylinder and its surroundings in another embodiment of the present invention. 10 Brake pedal (brake operating member) 12: Load cell (operating force detection device) 18: Main control device 20 Brake switch 38: Front wheel 40: Rear wheel 42.44 Brake cylinder 46.51, 54, 58: Liquid passage 48: Hydraulic pressure sensor (hydraulic pressure detection device) 60: Pump (hydraulic pressure source) 64: Reservoir tank 74: Rotation sensor (vehicle speed detection device) 78.104, 110, 128, 132: Analog switch 80: Staircase wave generation circuit (Operation force related signal generation circuit) 94: Subtraction circuit (ideal vehicle speed signal generation circuit) 96 2. Control signal generator 100; Sample hold circuit

Claims (3)

[Claims] (1) A vehicle brake device that brakes a vehicle by supplying hydraulic pressure from a hydraulic pressure source to a brake cylinder of a brake that suppresses rotation of a wheel in response to operation of a brake operating member, the hydraulic pressure source and the brake cylinder, and is provided in a fluid passage that connects the brake cylinder to a pressure increase permissible state in which at least the fluid pressure of the brake cylinder is allowed to be increased by the fluid pressure of the fluid pressure source and the fluid pressure of the brake cylinder is decreased by electrical control. an electro-hydraulic pressure control valve that can be switched to a pressure drop permissible state that allows the vehicle to brake; a vehicle speed detection device that outputs an actual vehicle speed signal corresponding to the actual vehicle speed of the vehicle; and an operating force that is applied to the brake operating member. an operating force detection device that outputs an operating force signal corresponding to the operation force detection device; and an operating force signal from the operating force detection device based on the vehicle speed at the time of starting braking, which is represented by the actual vehicle speed signal from the vehicle speed detection device at the time of starting operation of the brake operating member. an ideal vehicle speed determination means for determining an ideal vehicle speed that decelerates at a deceleration corresponding to the operating force expressed by the vehicle; and a comparison between the ideal vehicle speed determined by the ideal vehicle speed determination means and the actual vehicle speed represented by the actual vehicle speed signal from the vehicle speed detection device. If the ideal vehicle speed is high, outputting a pressure reduction signal to the electrohydraulic pressure control valve to switch it to the pressure reduction permissible state;
A vehicular brake device comprising: comparison means for outputting a pressure increase signal for switching to the pressure increase permissible state when the actual vehicle speed is high. (2) The ideal vehicle speed determining means includes a hold circuit that holds an actual vehicle speed signal representing the vehicle speed at the time of braking from the vehicle speed detecting device, and increases with the passage of time, and the increment is set to the operating force detecting device. an operating force-related signal generating circuit that outputs a larger operating force-related signal as the operating force signal from the operating force-related signal is larger, and subtracting the operating force-related signal from the operating force-related signal generating circuit from the actual vehicle speed signal held by the hold circuit. an ideal vehicle speed signal generation circuit that outputs an ideal vehicle speed signal, and the comparison means compares the ideal vehicle speed signal from the ideal vehicle speed signal generation circuit with the actual vehicle speed signal from the vehicle speed detection device, 2. The brake device according to claim 1, further comprising a comparison circuit that outputs the pressure reduction signal when the ideal vehicle speed signal is large and outputs the pressure increase signal when the actual vehicle speed signal is large. (3) A vehicle brake device that brakes a vehicle by supplying hydraulic pressure from a hydraulic pressure source to a brake cylinder of a brake that suppresses rotation of a wheel in response to the operation of a brake operating member, the hydraulic pressure source and the brake cylinder, and is provided in a fluid passage that connects the brake cylinder to a pressure increase permissible state in which at least the fluid pressure of the brake cylinder is allowed to be increased by the fluid pressure of the fluid pressure source and the fluid pressure of the brake cylinder is decreased by electrical control. an electro-hydraulic pressure control valve that can be switched to a pressure drop permissible state that allows the vehicle to brake; a vehicle speed detection device that outputs an actual vehicle speed signal corresponding to the actual vehicle speed of the vehicle; and an operating force that is applied to the brake operating member. an operating force detection device that outputs an operating force signal corresponding to the hydraulic pressure of the brake cylinder, a hydraulic pressure detection device that outputs a hydraulic pressure signal corresponding to the hydraulic pressure of the brake cylinder, and the vehicle speed detection device at the time of starting operation of the brake operating member. an ideal vehicle speed determination means for determining an ideal vehicle speed that decelerates from the vehicle speed at the start of braking indicated by the actual vehicle speed signal from the operating force detection device at a deceleration corresponding to the operating force indicated by the operating force signal from the operating force detection device; The ideal vehicle speed determined by the ideal vehicle speed determination means is compared with the actual vehicle speed represented by the actual vehicle speed signal from the vehicle speed detection device, and if the ideal vehicle speed is large, it is applied to the electro-hydraulic control valve to allow the voltage drop. a first comparison means that outputs a pressure reduction signal for switching to the state, and outputs a pressure increase signal for switching to the pressure increase permissible state when the actual vehicle speed is high; and the operating force detection device in a region where the vehicle speed is lower than the constant value. The ideal hydraulic pressure of the brake cylinder corresponding to the operating force signal from the hydraulic pressure detection device is determined, and the ideal hydraulic pressure is compared with the actual hydraulic pressure indicated by the hydraulic pressure signal from the hydraulic pressure detection device, and if the actual hydraulic pressure is high, and second comparison means that outputs the pressure reduction signal to the electrohydraulic pressure control valve and outputs the pressure increase signal when the ideal hydraulic pressure is high.