JP3921030B2 - Brake device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic brake device for a vehicle, and more particularly to a brake device having a structure in which a brake circuit for connecting an operation hydraulic pressure source such as a master cylinder and four wheel cylinders is divided into two systems.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there have been proposed devices that execute various automatic brake controls that automatically generate a braking force in a brake device. As this automatic brake control, for example, in an apparatus that automatically controls the inter-vehicle distance to the preceding vehicle to an optimum distance according to the speed, an automatic brake control that automatically generates a braking force when the inter-vehicle distance is reduced, Vehicle motion control that gives a braking force that generates a yaw moment in a direction that stabilizes the vehicle posture when the vehicle posture becomes unstable, such as excessive oversteer during turning, and acceleration slip occurs on the drive wheels Control executed when the driver is not performing braking operation, such as torque slip control that generates braking force to suppress this acceleration slip when the vehicle posture becomes unstable, or driving When a person performs a braking operation, such as by-wire control that generates a braking force according to the braking operation or a boost control that applies a braking force according to the braking operation. There is.
[0003]
By the way, the brake device generally connects the hydraulic pressure source and the wheel cylinder by a brake circuit divided into two systems so that one system can be secured and braked even if one system fails. Thus, in the brake device having a structure in which the brake circuit is divided into two systems, when the above-described automatic brake control is executed, when brake fluid is supplied from a pump as a hydraulic pressure source to each system, the brake circuit The fluid pressure fluctuation at In particular, when a plunger pump that discharges brake fluid when the plunger strokes is used as a pump, a pulse pressure is generated and the fluid pressure fluctuation increases. In addition, even if the same control signal is output to each of the two systems due to an error in assembly accuracy such as a valve that controls the hydraulic pressure in each of the two systems, the pressure that is output toward the wheel cylinder When the brake systems are divided on the left and right sides, there is a problem that yaw moment is generated in the vehicle due to the differential pressure between these systems, and the vehicle posture may become unstable.
[0004]
Therefore, as a conventional technique capable of solving such a problem, for example, a technique described in JP-A-10-203330 is known.
In this prior art, two brake circuits are communicated with each other through a communication path, and an electromagnetic switching valve is provided in the middle of the communication path. Therefore, if the electromagnetic switching valve is opened during braking, the brake circuits of both systems are communicated, and when the pump discharges the hydraulic pressure at a different phase to each system, both systems are communicated. It is possible to absorb the pressures and suppress the fluctuations in the hydraulic pressure, and to equalize the hydraulic pressures in the brake circuits of both systems and to stabilize the vehicle posture during braking.
[0005]
[Problems to be solved by the invention]
In the prior art as described above, the hydraulic pressure adjustment side is also in a state where the pump continues to supply brake fluid due to occurrence of a malfunction such as runaway control during execution of automatic brake control. If the pressure is reduced or held and no hydraulic pressure is supplied to the wheel cylinder, the brake circuit discharge part from the pump may become very high in the brake circuit and exceed the pressure resistance design value of the device. In such a case, there is a possibility that problems such as liquid leakage and breakage may occur.
Therefore, in order to prevent the occurrence of liquid leakage or breakage due to such abnormal high pressure, a high pressure relief valve is provided in parallel with the gate valve for opening and closing the brake circuit.
[0006]
However, this high-pressure relief valve is configured to always open when the pressure exceeds a predetermined pressure, and has a large number of parts and is expensive. Therefore, there is a problem that the size of the device increases and the cost of the device itself increases. .
[0007]
Therefore, an electromagnetic valve that can eliminate such a high-pressure relief valve has been proposed. As such an electromagnetic valve, for example, what is described in JP-A-8-93995 is known.
This prior art is characterized in that, in an electromagnetic valve having a structure in which a coil is energized to generate an attractive force and closed, a groove for narrowing the lines of magnetic force is formed in a part of a case that forms a magnetic path when energized.
Therefore, at the time of energization, the attractive force is saturated in the operating current range, and the maximum attractive force is limited to a predetermined value. Therefore, when this solenoid valve is used as a gate valve, if the pressure downstream of the gate valve in the brake circuit becomes high, the gate valve opens even in a maximum output state with a duty of 100% with respect to this gate valve, and the pressure Can escape. Therefore, the gate valve also serves as the high pressure relief valve, and the high pressure relief valve can be eliminated.
[0008]
However, when the inventors of the present application have studied the characteristics of the electromagnetic valve so that the above-described electromagnetic valve having a groove in the case is used as a gate valve, it has been found that there are the following problems to be solved.
In other words, when applied to a gate valve, the valve does not open in the control pressure range of the wheel cylinder, that is, the pressure range necessary to obtain a desired braking force, and the abnormal high pressure that greatly exceeds this pressure range ensures It is necessary to set the characteristics to open.
[0009]
FIG. 5 is a diagram showing the characteristics required as a gate valve of such a brake device, where Pn is the control region of the wheel cylinder WC, and the gate valve is absolutely not at the pressure in the control region Pn. It is necessary not to open the valve. Therefore, the pressure that never opens is shown as the target lower limit pressure PL in FIG. On the other hand, the solenoid valve must be opened at a predetermined relief pressure lower than the pressure resistance design value to release the hydraulic pressure. Therefore, this predetermined relief pressure is indicated by a target upper limit pressure PH in FIG. Therefore, the solenoid valve is set to open at the target upper limit pressure PH even when the maximum current IH is flowing.
In view of the value of the current to be energized in the control by the gate valve, when the maximum current Ih is set from the target upper limit pressure PH, the normal control region In, which is a current region that forms a pressure lower than the target lower limit pressure PL, is determined.
Here, when controllability is considered, in the normal control region In, the width of the control region Pn is wide, that is, the target lower limit pressure PL is secured as high as possible and the variable width is secured wide, while the target upper limit pressure PH is I want to set it as low as possible to ensure a large margin for the withstand voltage design value.
[0010]
However, when tuning is performed with the throttle amount in the case of the gate valve as in the above-described prior art, when the throttle amount is reduced, as indicated by NG in FIG. 5, the target lower limit pressure PL in the normal control region In is shown. However, the target upper limit pressure PH is also increased and a margin for the withstand voltage design value cannot be obtained. On the other hand, when the throttle amount is increased, as shown by OK in the figure, the target upper limit pressure PH can be lowered to obtain a margin for the withstand pressure design value, but the target lower limit pressure PL is also lowered, The variable range of the hydraulic pressure in the control region In becomes narrow, which is not preferable for control.
As described above, in the configuration in which the magnetic path is provided in the case as in the prior art, it is difficult to obtain desired characteristics.
[0011]
The invention of the present application has been made by paying attention to the above-mentioned conventional problems, and has a brake circuit divided into two systems, and performs automatic brake control upon receiving hydraulic pressure supplied from a hydraulic pressure source. In the brake device to be executed, it is possible to make the hydraulic pressures of the two brake circuits uniform when executing the automatic brake control, and the relief valve for relief of the high pressure is eliminated to reduce the cost and the size of the device. In addition, the objective is to achieve a balance between ensuring a relief function by ensuring a margin for the withstand voltage design value and obtaining high control performance by ensuring a wide pressure variable range in the control area. It is said.
[0012]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention connects an operation hydraulic pressure source that generates hydraulic pressure in response to a driver's braking operation and a wheel cylinder, and a first brake circuit and a second brake divided into two systems. The circuit is provided in the middle of each brake circuit and can be switched between a state where the brake circuit is communicated and a state where the brake circuit is disconnected. Open An out side gate valve, a control hydraulic pressure source capable of supplying brake fluid to the wheel cylinder side from the out side gate valve of the brake circuit, and a wheel cylinder side from the out side gate valve of the first brake circuit A communication path that communicates the wheel cylinder side with respect to the out-side gate valve of the second brake circuit, and a switching valve that is provided in the middle of the communication path and switches the communication path between a communication state and a cutoff state. In the brake device configured to generate a braking force by supplying brake fluid from a control hydraulic pressure source in a state where the out-side gate valve is closed, one of the two out-side gate valves Is a pressure-reducing out-side gate valve, and this pressure-reducing out-side gate valve is set to a characteristic corresponding to duty control during pressure-reducing control, and the other of the two out-side gate valves And relief for out-side gate valve, this relief for out-side gate valve But Energize maximum current value Been Valve closing This relief outgate valve when Set the valve opening pressure, which is the pressure to be opened, to a characteristic that is a predetermined relief pressure. And a brake control means for controlling the operation of the both out-side gate valves, the control hydraulic pressure source and the switching valve. The braking control means opens the switching valve and supplies the control hydraulic pressure source. The wheel cylinder pressure is adjusted by adjusting the pressure increase amount of the wheel cylinder based on the operating state of the control hydraulic pressure source and by adjusting the pressure reduction amount of the wheel cylinder based on the open state of both the out-side gate valves. When the automatic brake control is executed and when the automatic brake control is not executed, the switching valve is closed and the both out-side gate valves are opened. The normal pressure reduction control that duty-controls the valve opening amount of the pressure reducing out-side gate valve with the out-side gate valve fully closed, and the pressure reducing pressure with the relief out-side gate valve fully open. The valve opening amount of the up side gate valve to perform a rapid decompression control for duty control It is characterized by that.
[0014]
Claims 2 The invention described in claim 1 In the brake device described above, the control hydraulic pressure source includes a pump that sucks brake fluid from the operation hydraulic pressure source through the suction circuit, and an in-side that is provided in the middle of the suction circuit and communicates and blocks the suction circuit. And a gate valve.
[0015]
Operation and effect of the invention
When the driver performs a braking operation with both the out-side gate valves opened, hydraulic pressure is supplied from the operating hydraulic pressure source to the wheel cylinders via the first and second brake circuits, and braking force is generated. .
At this time, the switching valve is kept closed. Therefore, even if the communication path is blocked and there is an abnormality in one of the brake circuits, the other can function normally and a braking force can be obtained.
[0016]
Next, in the brake device, control for automatically generating a braking force by supplying brake fluid from a control hydraulic pressure source, for example, claim 1 When executing the automatic brake control described in 1), in both the first and second brake circuits, the out-side gate valve is closed and the switching valve is opened. Therefore, the brake fluid can be supplied from the control hydraulic pressure source in a state where the communication path is in a communication state and the first brake circuit and the second brake circuit are in communication, thereby generating a braking force. Therefore, a plunger pump is used as a control hydraulic pressure source, and hydraulic pressure is supplied to each brake circuit with pressure fluctuation, or there is an assembly error of each configuration in both the first and second brake circuits. Even if it exists, since both brake circuits are connected, pressure fluctuation can be suppressed and the pressure of both brake circuits can be equalized.
[0017]
Furthermore, in the present invention, the decompression out-side gate valve and the relief out-side gate valve are set to have different characteristics. Therefore, when the braking force is generated by the above control and the pressure between the two out-side gate valves and the wheel cylinder is higher than the relief pressure due to some abnormality, the two out-side gate valves Even when the maximum current value is supplied, the valve opening force due to the pressure of the brake circuit exceeds the valve closing force due to the electromagnetic force in the relief out-side gate valve.
Further, the pressure reducing out-side gate valve can release the pressure of both brake circuits and reduce the wheel cylinder pressure by opening the valve during the above-described control. In executing this pressure reduction control, it is possible to set a predetermined control characteristic, that is, the valve opening pressure with respect to the output duty ratio, without being restricted by the valve opening pressure when the maximum current value is passed. Can be improved.
[0018]
As described above, according to the present invention, it is possible to make the hydraulic pressures of the two brake circuits uniform when executing control for automatically generating braking force, and to relieve high pressure. Valves can be abolished to reduce costs and reduce the size of the device. In addition, a relief function is ensured by ensuring a margin for the pressure resistance design value, and a wide pressure variable range in the control area is secured. It is possible to achieve an effect that it is possible to achieve both high control performance.
[0019]
Also The braking control means executes automatic brake control. When this automatic braking control is executed, the control hydraulic pressure source is opened with both the first and second brake circuits communicating with each other. The amount of pressure increase is adjusted based on the supply operation state of the control hydraulic pressure source, and the pressure reduction amount is based on the open state of both out-side gate valves, that is, the amount of brake fluid released from the brake circuit. Thus, the wheel cylinder pressure is arbitrarily controlled. Since the pressure increase amount is determined by the supply operation of the control hydraulic pressure source in this way, the pressure increase amounts in the four wheel cylinders can be made uniform, and the pressure decrease amounts can be reduced by the two out side gate valves. Since it can be determined by the valve open state, the amount of pressure reduction can be made uniform as compared to controlling each wheel cylinder pressure independently.
[0020]
Also During pressure reduction in automatic brake control, depending on the required pressure reduction state, if the required pressure reduction amount is small, the relief out-side gate valve is maintained in a fully closed state and is opened by duty control of only the pressure-reducing out-side gate valve. The amount of pressure reduction is adjusted by controlling the valve amount. In this case, since the brake fluid escapes only through the pressure-reducing out-side gate valve from the first and second brake circuits closed by the both out-side gate valves, the pressure-reducing gradient becomes gentle. On the other hand, when the required pressure reduction amount is large, the relief out-side gate valve is fully opened, and the valve opening amount is controlled by duty control of only the pressure-reducing out-side gate valve to adjust the pressure reduction amount. In this case, a large amount of brake fluid escapes from the first and second brake circuits closed by both out side gate valves through the relief out side gate valve and escapes while being throttled through the decompression out side gate valve. Therefore, the decompression gradient becomes steep.
[0021]
Thus, the claim 1 In the description described in the above, the duty control is performed only for the pressure reducing gate valve, but by switching the relief out side gate valve between the fully closed state and the fully opened state, the duty control is switched between the slow pressure reducing and the sudden pressure reducing. Therefore, the resolution is higher than the controllable decompression gradient, and the control performance can be improved.
[0022]
Claim 2 In the invention described in, when supplying the brake fluid from the control hydraulic pressure source toward the brake circuit, the pump is operated by opening the in-side gate valve. As a result, the brake fluid from the operating fluid pressure source is sucked into the pump and discharged toward the brake circuit.
[0023]
[Embodiment]
Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment)
FIG. 1 is a brake circuit diagram showing a brake device according to an embodiment.
In the figure, MC is a master cylinder as an operating fluid pressure source. When the brake pedal BP is depressed, a brake circuit (first brake circuit) 1 and a brake circuit (second brake circuit) 2 are divided into two systems. It is a well-known thing which supplies toward wheel cylinder WC via. In the present embodiment, the brake circuits 1 and 2 have a so-called X piping structure, and the brake circuit 1 connects the wheel cylinder WC for the left front wheel and the wheel cylinder WC for the right rear wheel, 2 is configured to connect the wheel cylinder WC of the left front wheel and the wheel cylinder WC of the right rear wheel, but may be divided into a front wheel and a rear wheel.
[0024]
A decompression out-side gate valve 31 and a relief out-side gate valve 32 are provided in the middle of each of the brake circuits 1 and 2. Each of the out-side gate valves 31 and 32 is a normally-open solenoid valve that switches between connection and disconnection of the brake circuits 1 and 2, and functions differently as shown in the name, which will be described later. Each of the out-side gate valves 31 and 32 is a one-way valve that allows only the flow of brake fluid from the master cylinder MC side (hereinafter referred to as upstream) to the wheel cylinder WC side (hereinafter referred to as downstream). 30 are provided in parallel.
[0025]
In the brake circuits 1 and 2, a booster valve 5 including a solenoid-driven ON / OFF valve is provided downstream of each of the out-side gate valves 31 and 32. A pressure reducing valve 6 comprising a solenoid-driven ON / OFF valve is provided in the middle of the return passage 10 connecting the two. In parallel with the pressure increasing valve 5, a one-way valve 5a that allows only the flow returning upstream from the wheel cylinder WC is provided, and the brake fluid is smoothly returned from the wheel cylinder WC. .
[0026]
Further, a pump 4 as a control hydraulic pressure source is connected to the brake circuits 1 and 2. In other words, the pump 4 serves as a brake fluid pressure source during automatic brake control, and also serves as a return pump when the ABS control is executed. The pump 4 is a plunger pump that is operated by a motor M, and performs a pump function by a reciprocating stroke of a plunger (not shown). Each pump function part is connected via branched intake circuits 4a and 4b. The brake circuits 1 and 2 are connected to positions upstream of the out-side gate valves 31 and 32 and to the reservoir 7. On the other hand, the discharge circuit 4 c is connected to a position between the out-side gate valves 31 and 32 and the pressure increasing valve 5 in the brake circuits 1 and 2. The suction circuits 4a and 4b are provided with check valves 4d and 4e, respectively, for preventing the brake fluid from flowing backward.
[0027]
Further, the suction circuit 4a is provided with an in-side gate valve 9 as a switching valve for switching communication / blocking of the suction circuit 4a. The in-side gate valve 9 is constituted by a normally closed solenoid valve, and is opened when the pressure is increased in automatic brake control described later.
[0028]
Furthermore, in the present embodiment, in the brake circuits 1 and 2, the positions between the out-side gate valves 31 and 32 and the pressure increasing valve 5 are a part of the discharge circuits 4c and 4c and the communication passages 21a and 21b. The switching valve 22 including a normally closed solenoid valve that switches between communication and blocking of the communication paths 21a and 21b is provided in the middle of the communication paths 21a and 21b.
[0029]
In the brake device of the embodiment described above, when the driver performs a braking operation, the brake fluid of the master cylinder MC is supplied to each wheel cylinder WC via the brake circuits 1 and 2, and the braking force Will occur.
[0030]
In the present embodiment, ABS control and automatic brake control can be executed.
The ABS control is a control for preventing the wheel from locking when the driver performs a braking operation. When the wheel is about to be locked by performing the braking operation, the ABS control is connected to the wheel cylinder WC of the wheel. The pressure reducing valve 6 is opened and the pressure increasing valve 5 is closed to return the brake fluid of the wheel cylinder WC to the reservoir 7. Further, when the wheel recovers from the locking tendency, the pressure increasing valve 5 is opened and the pressure reducing valve 6 is closed to improve the braking force again. At this time, the pump 4 operates to return the brake fluid released to the reservoir 7 to the circuits 1 and 2.
[0031]
On the other hand, in the present embodiment, automatic braking control and boost control for automatically controlling the four wheel cylinders WC to the same pressure are executed as the automatic brake control.
Automatic braking control is a control that generates braking force as necessary in accordance with the execution of automatic travel control that keeps the distance between the vehicle and the front vehicle at a predetermined distance, and determines the target deceleration based on the vehicle speed and the distance between vehicles. Then, the wheel cylinder pressure is increased / held / reduced while the actual deceleration is fed back so that the determined target deceleration can be obtained. In the case of this automatic braking control, each of the out-side gate valves 31 and 32 is closed, while the in-side gate valve 9 is opened, and the pump 4 is operated to brake from the master cylinder MC via the suction circuit 4a. Liquid is sucked and discharged from the discharge circuit 4 c toward the circuits 1 and 2, and hydraulic pressure is generated in the brake circuits 1 and 2. The amount of pressure increase at this time can be adjusted by, for example, PWM control of the operation amount of the pump 4, that is, driving of the motor M, or by controlling the valve opening time of the pressure increase valve 5. On the other hand, in this embodiment, the decompression amount is controlled by controlling the valve opening amount of the decompression out-side gate valve 31 by PWM control, and, if necessary, the valve opening amount of the relief out-side gate valve 32 by PWM control. It can be adjusted by controlling.
[0032]
Further, the boost control determines the target wheel cylinder pressure based on the input from the means for detecting the braking operation performed by the driver, and the actual wheel cylinder pressure is obtained so that the determined target wheel cylinder pressure is obtained. The wheel cylinder pressure is increased, held and reduced while being fed back. Even in this boost control, each of the out-side gate valves 31 and 32 is closed while the in-side gate valve 9 is opened and the pump 4 is operated as in the above-described automatic braking control. The hydraulic pressure is supplied toward the wheel cylinder WC, and pressure increase / hold / pressure reduction is executed by the same means as in the automatic braking control described above.
[0033]
Here, each of the out-side gate valves 31 and 32 will be described.
FIG. 2 is a cross-sectional view showing the out-side gate valves 31 and 32. A seat plug 3b is fixed to a cylindrical valve body 3a, and a plunger 3c is brought into contact with and separated from a seat surface formed on the seat plug 3b. Is slidably inserted. An armature 3d is provided integrally with or in contact with the base end of the plunger 3c.
A coil 3f is wound around the outside of a cylinder 3e that is fitted to the upper end of the valve body 3a and accommodates the armature 3d. Reference numeral 3g denotes a case covering the coil 3f.
The lower end surface of the armature 3d is an adsorption surface that attracts the upper end surface of the valve body 3a when the coil 3f is energized, and there is an air gap 3h between the adsorption surface and the upper end surface of the valve body 3a. Is provided.
[0034]
The configuration described above is common to the decompression out-side gate valve 31 and the relief out-side gate valve 32.
Next, the difference between the two will be described. The relief out-side gate valve 32 sets the size of the air gap 3h smaller than the decompression out-side gate valve 31, and the number of turns of the coil 3f. The resistance of the coil 3f is increased. As a result of such setting, the characteristics of both the out-side gate valves 31 and 32 are such that the characteristic of the relief out-side gate valve 32 indicated by T32 in FIG. The valve closing pressure when the maximum current value flows is set higher than the characteristic of 31.
In the figure, I31 is a current control range of the pressure reducing out-side gate valve 31, and duty control is executed in this current control range I31. Further, when 100% duty is output to the decompression out-side gate valve 31, it is assumed that a current of Imax is energized.
On the other hand, in the figure, I32 indicates a current control range output to the relief out-side gate valve 32. This current control range I32 includes a minimum current IL at a high temperature (low viscosity) and a low voltage, and a low temperature. (High viscosity) ・ Two currents are output, the maximum current IH at high voltage.
[0035]
Next, the operation of the embodiment will be described.
B) When the driver performs a braking operation
Normally, the valves 5, 6, 9, 31, 32 and the motor M are not energized. Therefore, the pressure increasing valve 5 is fully open, the pressure reducing valve 6 is fully closed, the in-side gate valve 9 is fully closed, both the out-side gate valves 31 and 32 are fully open, and the motor M stops. ing.
[0036]
In this state, when the driver performs a braking operation and a master cylinder pressure is generated, brake fluid is supplied from the master cylinder MC to the wheel cylinder WC via the brake circuits 1 and 2 to generate a braking force. At this time, the switching valve 22 is maintained in a closed state and is disconnected from the communication passages 21a and 21b that allow the brake circuits 1 and 2 to communicate with each other. However, a detailed description is omitted for the master cylinder MC. However, the function of making the hydraulic pressure supplied toward the two brake circuits 1 and 2 uniform is provided, and the braking force does not differ between the two systems.
Further, when an abnormality such as liquid leakage occurs in one of the brake circuits 1 and 2, liquid leakage in the other can be prevented by blocking by the switching valve 22, and a braking force can be reliably generated.
Note that, during the ABS control, since the driver is performing a braking operation, the switching valve 22 is kept in a closed state and independently controls the hydraulic pressure of each wheel cylinder WC.
B) Automatic brake control
When the automatic braking control and the boost control described above are executed, the switching valve 22 is opened and the communication path 21a and the communication path 21b are communicated with each other by executing the brake circuit 1, 2 is connected to supply brake fluid from the pump 4 to the brake circuits 1 and 2.
[0037]
In this state, as described above, when the pressure increase is determined, the in-side gate valve 9 is opened, while the out-side gate valves 31 and 32 are closed, and in this state, the motor M is duty controlled. Thus, the wheel cylinder pressure increase is controlled. Thus, since the pressure increase amount of the four wheel cylinders WC is controlled by the duty control of the motor M, the four wheel cylinder pressures can be easily made uniform.
[0038]
Further, at the time of holding, both the out-side gate valves 31 and 32 are closed, the in-side gate valve 9 is closed, and the motor M is stopped, or the discharge speed is not actually generated. Rotate (idling rotation). When idling is rotated in this way, the responsiveness when shifting to pressure increase control is excellent.
[0039]
At the time of pressure reduction judgment, if the pressure reduction pressure gradient is gentle and normal pressure reduction, the relief out-side gate valve 32 and the in-side gate valve 9 are closed and the motor M is stopped or idling rotated. The amount of opening of the pressure reducing out-side gate valve 31 is duty-controlled within the current control range I31 shown in FIG. 3 in accordance with the target deceleration or the target wheel cylinder pressure. The decompression pressure gradient in this case is the gradient indicated by G1 in FIG.
[0040]
On the other hand, when executing a sudden pressure reduction with a steep pressure reduction pressure gradient, the in-side gate valve 9 is closed, the motor M is stopped or idling is rotated, and the relief out-side gate valve 32 is fully opened in this state. Above, the valve opening amount of the pressure reducing out-side gate valve 31 is duty-controlled. The decompression pressure gradient in this case is the gradient indicated by G2 in FIG.
[0041]
Therefore, in the present embodiment, when the decompression out-side gate valve 31 is controlled in the current control range I31, the relief out-side gate valve 32 is closed, and when the relief out-side gate valve 32 is fully opened. It is possible to obtain two kinds of pressure-reducing pressure gradients, and the resolution can be substantially improved and control performance can be improved.
In addition, since the pressure reduction amounts of the four wheel cylinders WC are determined by duty-controlling one pressure-reducing out-side gate valve 31, the four wheel cylinder pressures can be easily made uniform.
C) When abnormally high pressure occurs
While the pressure increase control is being executed with both the out-side gate valves 31 and 32 fully closed, an abnormality occurs between the out-side gate valves 31 and 32 and the wheel cylinder WC in the brake circuits 1 and 2. When a high pressure occurs, at this time, it is assumed that a current Imax of 100% duty ratio is supplied to the pressure reducing out-side gate valve 31 and a maximum current IH is supplied to the relief out-side gate valve 32. When the abnormal high pressure exceeds the relief pressure P0, the relief out-side gate valve 32 is opened to release the high pressure to the master cylinder side.
[0042]
As described above, since the decompression out-side gate valve 31 and the relief out-side gate valve 32 are provided as the out-side gate valves, the decompression out-side gate valve 31 has a maximum current as a setting corresponding to the decompression control. Even when the pressure when a certain 100% duty ratio is given increases, the relief out-side gate valve 32 is opened at a pressure that secures a margin for the withstand voltage design value when the maximum current is given. By setting, the relief function can be surely obtained.
[0043]
As described above, in the present embodiment, the communication passages 21a and 21b and the switching valve 22 are provided. Therefore, even if there is an assembly error, the two brake circuits 1 and 2 are executed when the automatic brake control is performed. Can be made uniform in the hydraulic pressure, and when the automatic brake control is performed, the out side gate valve that closes the connection between the master cylinder MC and the wheel cylinder WC is relieved as the decompression out side gate valve 31 and the relief. Therefore, the relief out-gate valve 32 is provided with a high-pressure relief function to eliminate the relief valve that relieves high pressure, thereby reducing costs and downsizing the device. In addition, it is possible to ensure a relief function by ensuring a margin for the withstand voltage design value, and variable pressure in the control area. There is an advantage that it is possible to achieve both to obtain a wide secured to high control performance.
[0044]
Moreover, in the present embodiment, during pressure reduction in automatic brake control, during normal pressure reduction, the pressure-reducing out-side gate valve 31 is duty-controlled with the relief out-side gate valve 32 closed, and during sudden pressure reduction, a relief out Since the pressure-reducing out-side gate valve 31 is configured to be duty-controlled with the side gate valve 32 fully opened, it is possible to obtain two kinds of pressure-reducing gradients, improve control resolution, and improve control performance. The effect that improvement can be aimed at is acquired.
[0045]
Although the embodiment has been described with reference to the drawings, the present invention is not limited to this embodiment.
For example, in the embodiment, the master cylinder is shown as the operating fluid pressure source. However, the pump that detects the operation amount of the driver and mechanically forms the fluid pressure, or the accumulator that stores the fluid pressure supplied from the pump. Etc. can be used.
[Brief description of the drawings]
FIG. 1 is a brake circuit diagram illustrating a brake device according to an embodiment.
FIG. 2 is a cross-sectional view showing an out-side gate valve in the brake device of the embodiment.
FIG. 3 is a characteristic diagram of a pressure reducing out-side gate valve and a relief out-side gate valve according to a second embodiment.
FIG. 4 is a pressure reduction characteristic diagram of the embodiment.
FIG. 5 is a characteristic explanatory diagram of a conventional technique.
[Explanation of symbols]
1 Brake circuit
2 Brake circuit
3a Valve body
3b Seat plug
3c Plunger
3d amateur
3e cylinder
3f coil
3h Air gap
4 Pump
4a Inhalation circuit
4b Inhalation circuit
4c Discharge circuit
4d, 4e check valve
5 Booster regulator
5a One-way valve
6 Pressure reducing valve
7 Reservoir
9 Inn side gate valve
10 Return passage
21a Communication passage
21b Communication path
22 Switching valve
30 One-way valve
31 Out gate valve for pressure reduction
32 Out side gate valve for relief
M motor
MC master cylinder
WC wheel cylinder

Claims (2)

A first brake circuit and a second brake circuit divided into two systems by connecting an operating hydraulic pressure source that generates hydraulic pressure in response to a driver's braking operation and a wheel cylinder;
A normally- open out-side gate valve that is provided in the middle of each brake circuit and can be switched between a state in which the brake circuit is communicated and a state in which the brake circuit is disconnected;
A control hydraulic pressure source capable of supplying brake fluid to the wheel cylinder side from the out side gate valve of the brake circuit;
A communication path for communicating the wheel cylinder side with respect to the out-side gate valve of the first brake circuit and the wheel cylinder side with respect to the out-side gate valve of the second brake circuit;
A switching valve provided in the middle of the communication path to switch the communication path between a communication state and a cutoff state, and supplying brake fluid from a control hydraulic pressure source with the out-side gate valve closed In the brake device configured to be able to generate a braking force,
One of the two out-side gate valves is used as a decompression out-side gate valve, and the decompression out-side gate valve is set to a characteristic according to duty control during decompression control,
The other of the two outside gate valve and relief outside gate valve, when the relief outside gate valve is closed is energized the maximum current value, the relief outside gate valve opens Set the valve opening pressure that is the valve pressure to the specified relief pressure ,
Braking control means for controlling the operation of both the out-side gate valve, the control hydraulic pressure source and the switching valve is provided,
The braking control means opens the switching valve, supplies and operates the control hydraulic pressure source, adjusts the pressure increase amount of the wheel cylinder based on the operating state of the control hydraulic pressure source, and The automatic brake control for controlling the wheel cylinder pressure is performed by adjusting the pressure reduction amount of the wheel cylinder based on the open state of the gate valve, and when the automatic brake control is not executed, the switching valve is closed. It is the structure which opens both out side gate valves,
During pressure reduction during automatic brake control, the relief out-side gate valve is fully closed and the decompression out-side gate valve is controlled in duty, and the relief out-side gate valve is fully open and the relief out-side gate valve is fully open. A brake device characterized by executing sudden pressure reduction control for duty-controlling the valve opening amount of the side gate valve . The control hydraulic pressure source includes a pump that sucks brake fluid from an operation hydraulic pressure source via an intake circuit, and an in-side gate valve that is provided in the middle of the intake circuit and communicates and blocks the intake circuit. The brake device according to claim 1, wherein:

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