JP4437889B2 - Brake control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brake control device, and more particularly to a brake control device that can actively generate a brake fluid pressure.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a brake control device that can generate a braking force even when a driver does not operate a brake pedal.
Specifically, according to the running state of the vehicle, the pump is driven to generate a hydraulic pressure, and this hydraulic pressure is supplied to the wheel cylinder, so that the braking force can be actively applied even in the absence of the driver's braking operation. Is generated. The control for actively generating the braking force in this way is hereinafter referred to as active braking control.
[0003]
As a device for executing such active braking control, for example, a traction control device, a vehicle attitude control device, an automatic braking device, a brake assist device, and the like described in Patent Document 1 are known.
[0004]
Further, in a brake control device that performs such active braking control, an out-side gate valve that opens and closes a brake circuit that connects the master cylinder and the wheel cylinder, and a suction circuit that connects the master cylinder and the suction side of the pump. An in-side gate valve that opens and closes is provided.
During active braking control, the in-side gate valve is opened so that the brake fluid of the master cylinder can be sucked into the pump, and the out-side gate valve is closed, so that the hydraulic pressure supplied from the pump to the wheel cylinder side is It is configured not to escape.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-250544.
[0006]
[Problems to be solved by the invention]
As described above, in the prior art, at the time of active braking control, the out side gate valve is closed while the in side gate valve is opened, and the pump is driven to supply the brake fluid of the master cylinder to the wheel cylinder side.
In this state, when the driver performs a braking operation, the master cylinder pressure acts on the pump through the in-side gate valve, which may reduce the durability of the pump components (such as seal members). There was a problem that there was.
[0007]
The present invention is made by paying attention to the above-mentioned conventional problems, and when the driver performs a braking operation during the active braking control, the active braking control is performed while protecting the pump components from high pressure. It aims at providing the brake control device which enables.
[0008]
[Means for Solving the Problems]
  In the brake control device of the present invention according to claim 1,When the driver's braking operation is not detected during active braking control, the control unit performs transmission prevention standby control that opens and closes the in-side gate valve at a predetermined interval, and when the driver's braking operation is detected. Is configured to close the in-side gate valve.
Operation and effect of the invention
  In the brake control device according to the first aspect of the present invention, when it is determined that the braking force is necessary according to the traveling state regardless of the driver's braking operation according to the traveling state of the vehicle, The braking control is executed to automatically generate a braking force.
  During this active braking control, the control unit opens the in-side gate valve and operates the pump, whereby the brake fluid of the master cylinder is supplied toward the brake circuit.
  Further, the control unit operates the pressure adjusting means to adjust the pressure of the brake fluid supplied from the pump and supplies the brake fluid to the wheel cylinder. Therefore, a necessary braking force can be obtained at a desired wheel.
[0009]
  Execution of this active braking controlWhen the driver's braking operation is not detected,Inn side gate valveWaiting for transmission to open and closeExecute controlWhen the driver's braking operation is detected, the in-side gate valve is closed so that when the driver starts the braking operation during active braking control, active braking is performed while protecting the pump components from high pressure. Control can continue.
  In the invention according to claim 2,During the execution of active braking control, the driver performs braking operation.StartIn this case, the control unit executes high-pressure transmission prevention control that outputs drive vibration having a predetermined opening / closing duty ratio to the in-side gate valve. The in-side gate valve that has received this drive signal repeatedly opens and closes according to the duty ratio, thereby limiting the flow rate of the brake fluid in the suction circuit.
  Therefore, the high pressure generated in the master cylinder by the driver's braking operation is throttled by the in-side gate valve in the suction circuit, and the high pressure is not transmitted to the pump as it is, thus protecting the pump components from the high pressure. Can do. Further, since the in-side gate valve is not completely closed, the pump sucks and discharges the brake fluid, and the active braking control is continued.
  Therefore, in the present invention, the driver performs a braking operation during the active braking control.StartThe active braking control can be continued while protecting the pump components from high pressure.
[0010]
  Next, the claim3In the above-described invention, when executing the above-described high-pressure transmission prevention control, when a driving signal having an opening / closing duty ratio is output to the in-side gate valve, the in-side gate valve opens and closes as follows.
  In this in-side gate valve, in the closed state, in the valve body and the small diameter plug, a differential pressure between the high pressure on the upstream master cylinder side and the low pressure on the pump side downstream acts. Yes.
  In the valve closed state, naturally, the high pressure of the master cylinder is not transmitted to the pump side and does not adversely affect the pump components.
[0011]
  When opening the valve from this state, first, the valve body moves to open the small diameter port. At this time, since the cross-sectional area of the small-diameter port closed by the valve body is relatively small compared to the large-diameter port, the force acting in the valve closing direction due to the differential pressure is also relatively small, and the valve body is opened with a small force. The valve can be operated.
  When the small-diameter port is open, a small flow rate of brake fluid can be circulated. Therefore, even in this state, the master cylinder pressure is difficult to be transmitted to the pump.
  Thereafter, the differential pressure between the upstream and downstream of the small-diameter plug is reduced by the flow through the small-diameter port, the small-diameter plug is moved by the urging force of the urging means, and the large-diameter port is opened.
  In the open state of the large-diameter port, a large flow of brake fluid is circulated, and the brake fluid is supplied from the pump toward the brake circuit.
  By supplying the brake fluid, the active braking control can be continued. Further, by restricting the valve opening time of the large-diameter opening within a predetermined time, a necessary flow rate can be secured for the pump, but high pressure can be prevented from being transmitted.
[0012]
  Next, when the valve is closed, the valve body is moved in the valve closing direction, the valve body is brought into contact with the small diameter plug to close the small diameter port, and from this state, the valve body is further moved in the valve closing direction. As a result, the small-diameter plug contacts the large-diameter plug and closes the large-diameter opening. As a result, a differential pressure is generated between the upstream side and the downstream side in the in-side gate valve.
  In the above opening and closing, the valve body is urged in the valve closing direction, while the small-diameter plug is urged in the valve opening direction with an urging force smaller than the urging force against the valve body, and the valve body is driven by the solenoid. The valve body may be moved in the valve opening direction, or the valve body and the small diameter plug may be biased in the valve opening direction, and the valve body may be moved in the valve closing direction by the driving force of the solenoid.
[0013]
  As described above, the claims3In the invention described in 2, a valve having a two-stage valve structure is used as the in-side gate valve.TatterTherefore, even when a high pressure is generated in the master cylinder, the force acting on the valve body can be suppressed to be small and the valve can be opened with a small suction force or urging force. The size of the side gate valve can be reduced.
[0014]
  Claim4In the invention described in the above, when outputting the drive signal in the high pressure transmission prevention control, the control unit closes the opening / closing duty ratio of the drive signal as the master cylinder pressure increases in accordance with the detected master cylinder pressure. Control is performed so that the duty ratio is high.
  Therefore, according to the master cylinder pressure, it is possible to achieve a high level balance between prevention of transmission of high pressure in the in-side gate valve and securing of a necessary flow rate.
[0015]
  Claims5In the invention described in, since the master cylinder pressure is detected based on the longitudinal acceleration of the vehicle and the wheel speed, the existing sensor necessary for active braking control is used for detecting the master cylinder pressure. Therefore, the cost can be reduced and the apparatus can be made compact.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below with reference to the drawings.
  FIG. 1 is an overall view showing a brake control device according to an embodiment of the present invention..
In the figure, MC is a master cylinder, which is a well-known cylinder that supplies brake fluid to the wheel cylinder WC via the brake pipes 1 and 2 when the brake pedal BP is depressed. The master cylinder MC is provided with a reservoir RES that stores brake fluid.
[0020]
The brake pipes 1 and 2 have a connection structure called a so-called X pipe. That is, the brake pipe 1 connects the left front wheel cylinder WC (FL) and the right rear wheel cylinder WC (RR), and the brake pipe 2 connects the right front wheel cylinder WC (FR) and the left rear wheel. The wheel cylinder WC (RL) is connected. In the following description, when a specific wheel cylinder is not pointed out, the display in () is omitted and simply displayed as WC.
[0021]
An out-side gate valve 3 is provided in the middle of the brake pipes 1 and 2. The out-side gate valve 3 is a normally-open solenoid valve that switches between connection and disconnection of the brake pipes 1 and 2, and variably controls the opening degree by PWM control during active braking control. A one-way valve 3 a is provided in parallel with the out-side gate valve 3. The one-way valve 3a 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).
[0022]
Further, in the brake pipes 1 and 2, an inflow valve 5 composed of a solenoid-driven normally open ON / OFF valve is provided downstream of the out-side gate valve 3.
Furthermore, an outflow valve 6 comprising a solenoid-driven normally closed ON / OFF valve is provided in the middle of a return passage 10 connecting the downstream position with respect to the inflow valve 5 and the reservoir 7.
Therefore, if the inflow valve 5 is opened and the outflow valve 6 is closed, the brake circuits 1 and 2 are in a pressure increasing state allowing flow between the upstream and the downstream, and the valves 5 and 6 can be closed. For example, when the brake fluid pressure is held in the wheel cylinder WC, the inflow valve 5 is closed and the outflow valve 6 is opened, so that the brake pressure in the wheel cylinder WC is released to the reservoir 7. .
In addition, a bypass circuit 51 is provided in parallel with the inflow valve 5, and the bypass circuit 51 is provided with a one-way valve 52 that allows only fluid return from the wheel cylinder WC toward the master cylinder MC.
[0023]
Further, a pump 4 is connected to the brake pipes 1 and 2. The pump 4 serves as a brake fluid pressure source during active braking control, and also serves as a return pump when ABS control is executed.
The pump 4 is a plunger pump that is operated by a motor 8 and includes two plungers 4p and 4p, and a pump chamber 4r that performs suction and discharge by the plungers 4p and 4p.
The pump chamber 4r is connected to a position upstream of the out-side gate valve 3 in the brake pipes 1 and 2 and the reservoir 7 via branched intake circuits 4a and 4b, while the discharge circuit 4c. The brake pipes 1 and 2 are connected to a position between the out-side gate valve 3 and the inflow valve 5.
The suction circuit 4b is provided with a check valve 4d for preventing the brake fluid from flowing in the direction of the reservoir 7.
[0024]
Here, FIG. 2 shows an example of the plunger portion of the pump.
As shown in the figure, the plunger 4p is supported so as to be slidable in the vertical direction in the figure with respect to the pump chamber 4r. The plunger 4p is formed with a through hole 41 connected to the suction circuits 4a and 4b, and in the middle of the through hole 41, a suction valve that opens in a suction stroke for expanding the volume of the pump chamber 4r. A valve 42 is provided. Further, a plug 43 that closes the lower end of the pump chamber 4r in the drawing is provided with a discharge valve 44 that opens in a compression stroke that reduces the volume of the pump chamber 4r. Further, a seal member 45 for preventing the brake fluid of the suction circuits 4a and 4b from leaking to the cam side is provided on the outer periphery of the upper end of the pump chamber 4r. A sealing material 46 is provided to prevent the brake fluid from leaking to the suction circuit side.
[0025]
  The suction circuit 4a is provided with an in-side gate valve 9 for switching communication / blocking of the suction circuit 4a. The in-side gate valve 9 is a normally closed solenoid valve.
Here, the configuration of the in-side gate valve 9 will be described with reference to the cross-sectional view of FIG. In FIG. 3, although (a) will be described later, it is in the small-diameter opening state, and (b) shows the large-diameter opening state.
This in-side gate valve 9 has a two-stage valve structure.The
That is, the in-side gate valve 9 includes a large diameter plug 91, a small diameter plug 92, and a valve body 93. The large-diameter plug 91 is fixed to one end of the cylinder 90, a large-diameter communication hole 91a is penetrated in the axial direction, and a large-diameter port 91b is opened at one end of the large-diameter communication hole 91a.
The suction circuits 4a and 4b have a pump side connected to the other end of the large diameter communication hole 91a and a master cylinder side connected between the large diameter plug 91 and the small diameter plug 92.
[0026]
The small-diameter plug 92 is accommodated in the cylinder 90 so as to be movable in the axial direction, and one end thereof is formed so as to be seated in the large-diameter opening 91b. Then, it can be switched between a state of being seated on the large diameter port 91b by moving in the axial direction and a state of being separated from the large diameter port 91b, and a plug spring 92a interposed between the large diameter plug 91 and It is biased in a direction away from the large diameter port 91b.
A small-diameter communication hole 92b having a diameter smaller than that of the large-diameter communication hole 91a passes through the shaft center portion of the small-diameter plug 92, and a small-diameter opening 92c is opened at the other end of the small-diameter communication hole 92b.
Further, on the outer periphery of the small-diameter plug 92, a flow path 92d through which brake fluid can flow is formed between the small-diameter plug 92 and the inner periphery of the cylinder 90.
[0027]
The valve body 93 is accommodated in a cylindrical cylindrical member 90a fixed to the cylinder 90 so as to be movable in the axial direction, and is interposed between a plug 94 fixed to one end of the cylindrical member 90a. The body spring 93a is biased in a direction to close the small diameter opening 92c. The valve body spring 93a is set to a biasing force larger than that of the plug spring 92a. Normally, the valve body spring 93a presses the valve body against the small diameter port 92c, and the small diameter plug 92 is pressed by this pressing force. When pressed against the large-diameter port 91b, both the small-diameter port 92c and the large-diameter port 91b are closed and the valve is closed.
The valve body 93 is configured to open the small-diameter opening 92c against the urging force of the valve body spring 93a by a suction force of a solenoid (not shown).
A groove 93 b for turning the hydraulic pressure to the back surface of the valve body 93 is formed on the outer periphery of the valve body 93.
[0028]
Accordingly, in the in-side gate valve 9, when a solenoid (not shown) is energized, the valve body 93 is separated from the small diameter plug 92, and first, the small diameter port 92c is opened as shown in FIG. At this time, when hydraulic pressure is generated on the master cylinder side of the suction circuit, the valve body 93 is caused by the difference in pressure receiving area between the high pressure side (master cylinder side) and the low pressure side (pump side) of the valve body 93. However, since the pressure receiving area difference is a small area difference due to the small-diameter port 92c, the pressure in the valve closing direction is small, and the valve can be opened even if the suction force of the solenoid is small.
[0029]
By opening the small-diameter port 92c, a small amount of brake fluid is circulated in the suction circuit via the small-diameter through hole 92b. In this case, although the flow rate is small, if this flow is made and the hydraulic pressure difference between the upstream and downstream of the small-diameter plug 92 becomes small, then the small-diameter plug 92 moves upward in the figure by the urging force of the plug spring 92a. Then, the large diameter port 91b is opened as shown in FIG. In this state, a large amount of brake fluid is circulated in the suction circuit.
[0030]
When the energization to the solenoid is cut, the valve body 93 moves downward in the figure by the urging force of the valve body spring 93a to close the small diameter port 92c of the small diameter plug 92, and further, the small diameter plug 92 is moved downward in the figure. Press. As a result, the small diameter plug 92 moves together with the valve body downward in the figure until it contacts the large diameter plug 91 and closes the large diameter port 91b.
As a result, the small-diameter port 92c and the large-diameter port 91b are closed.
[0031]
The configuration enclosed by the square frame in FIG. 1 described above is incorporated in one housing as the brake unit H / U.
The operation of the two gate valves 3, 9, the inflow valve 5, the outflow valve 6 and the motor 8 in the brake unit H / U is controlled by the control unit CU shown in FIG.
This control unit CU is closed when the driver steps on the brake pedal, the wheel speed sensor 12 that detects the wheel speed, which is the rotational speed of each wheel, the front / rear G sensor 14 that detects the longitudinal acceleration of the vehicle. Based on the input from the brake switch 13, ABS control and active braking control are executed.
[0032]
The ABS control is a well-known control. In brief, in this embodiment, the wheel lock during braking is determined based on the input from the wheel speed sensor 12, and the wheel is likely to lock. Once the wheel cylinder pressure is reduced to avoid wheel lock, the wheel speed of the target wheel is reduced and maintained as appropriate so that the wheel speed becomes the most effective speed for braking, which is lower than the vehicle speed by a predetermined value.・ To increase pressure. In the pressure reduction / holding / pressure increase in the ABS control, in the case of pressure reduction, the inflow valve 5 is closed and the outflow valve 6 is opened, and in the case of holding, both valves 5 and 6 are closed, In the case of pressure increase, the inflow valve 5 is opened and the outflow valve 6 is closed. During decompression, the brake fluid in the wheel cylinder WC is released to the reservoir 7. The brake fluid accumulated in the reservoir 7 is returned to the brake pipes 1 and 2 as needed based on the operation of the pump 4.
[0033]
Next, active braking control will be described. As this active braking control, for example, automatic braking control, vehicle motion control, traction control control, and the like are known.
The automatic braking control is a control that automatically performs braking when the driver is not performing a braking operation. For example, the preceding vehicle is maintained while keeping the inter-vehicle distance from the preceding vehicle at a preset ideal inter-vehicle distance. This is executed when the inter-vehicle distance is shorter than the ideal inter-vehicle distance in executing automatic follow-up control for following the vehicle. In this automatic braking control, a target deceleration is set according to the running state, and a braking force is automatically generated so that this target deceleration can be obtained.
Vehicle motion control also automatically applies braking force to the desired wheels when the vehicle is in an overoversteering state or overundersteering state and the vehicle posture becomes unstable. In this control, yaw moment is generated in the direction of stabilization.
The traction control control is a control for eliminating the torque slip by applying a braking force to the driving wheel when a torque slip is generated due to an excessive driving force applied to the driving wheel.
[0034]
In executing the above-described active braking control, in the present embodiment, the inflow valve 5 and the outflow valve 6 are in a non-energized state and the inflow valve 5 is opened and the outflow valve 6 is closed to increase the pressure. In this case, the out-side gate valve 3 is closed and the in-side gate valve 9 is opened and the pump 4 is operated, whereby the brake fluid is supplied to the wheel cylinder WC. The amount of pressure increase is arbitrarily controlled by driving the motor 8 with PWM. In this case, the pressure increase amount may be controlled by further PWM controlling the opening degree of the inflow valve 5.
On the other hand, when the pressure is reduced, the in-side gate valve 9 is closed, the motor 8 of the pump 4 is idlingly rotated so as not to generate a discharge amount, and the out-side gate valve 3 is opened to open the wheel cylinder WC. The brake fluid is discharged toward the master cylinder MC, and the amount of pressure reduction is arbitrarily controlled by PWM controlling the valve opening amount of the out-side gate valve 3.
[0035]
In the present embodiment, when executing the above-described active braking control, the high pressure transmission prevention is performed so that the high pressure is not transmitted to the pump when the driver performs a braking operation using the in-side gate valve. Execute control.
FIG. 4 is a flowchart showing the flow of the high-pressure transmission prevention control, and this control is started together with the execution of the active braking control.
First, in step 401, it is determined whether or not the brake switch is ON, that is, whether or not the driver has performed a braking operation. When the brake switch is ON, the process proceeds to step 402, and when the brake switch is OFF, the process returns to the start.
[0036]
  In step 402, longitudinal acceleration is read from the longitudinal G sensor.
In the next step 403, the wheel speed of each wheel is read from the wheel speed sensor.
Next, in step 404, the master cylinder pressure is estimated based on the front and rear G and the wheel speed.
In estimating the master cylinder pressure, first, the road surface friction coefficient is estimated based on the read differential value (rate of change) of the wheel speed. Then, based on the relationship between the vehicle speed at the time of braking (this vehicle speed is obtained from the wheel speed, and the highest speed among the wheel speeds is the vehicle speed) and the front-rear G, it is made for each road friction coefficient. Estimate the master cylinder pressure based on the mapThe
[0037]
In the next step 405, a duty ratio corresponding to the estimated master cylinder pressure is selected from a preset duty characteristic map, and in the next step 406, a drive signal composed of an ON / OFF signal of this duty ratio is set to the in side. Processing to output to the gate valve 9 is executed.
[0038]
The operation of the in-side gate valve 9 receiving this drive signal will be described with reference to the time chart of FIG.
In FIG. 6A, active braking control is started at time t1, and as shown in the control pattern, active pressure increase (active pressure increase) is started at time t1, and the wheel cylinder pressure increases. ing. Further, in the current active braking control, active pressure reduction is executed at time t3, and thereafter, hydraulic pressure is maintained from time t4.
[0039]
At time t2 during the active pressure increase by the active braking control, the driver starts the braking operation, and accordingly, the master cylinder pressure starts to increase. At the time of pressure increase during this active braking control, the out-side gate valve 3 is closed when an ON signal is input, as shown in FIG. The in-side gate valve 9 is opened when an ON signal is input. Further, when the pump 4 is driven, the brake fluid in the master cylinder MC is sucked into the pump 4 through the suction circuit and then discharged to the brake circuit.
In this state, when the driver performs a braking operation and the master cylinder pressure increases, this high pressure is transmitted to the pump 4 through the suction circuit, and the durability of the seal portions 45 and 46 in the pump 4 is deteriorated. Become.
[0040]
  On the other hand, in the present embodiment, as described above, when the brake switch is turned on by the driver's braking operation, the high pressure transmission prevention control is executed, so that at t2 in FIG. At that time, a drive signal with a duty ratio corresponding to the master cylinder pressure is output to the in-side gate valve 9.The
[0041]
When the solenoid of the in-side gate valve 9 is energized by this drive signal, the in-side gate valve 9 shown in FIG. 3 repeats closing and opening from the previous opened state.
Here, when the in-side gate valve 9 is switched from the closed state to the open state, as described above, first, the valve body 93 opens the small-diameter port 92c, and the small-diameter through hole 92b in the small-diameter plug 92 is used. When a small amount of brake fluid can be circulated and then the hydraulic pressure difference between the upstream and downstream of the small-diameter plug 92 becomes small, the small-diameter plug 92 is displaced in the valve opening direction, and the large-diameter communication in the large-diameter plug 91 occurs. A large amount of brake fluid can be distributed through the holes 91a.
[0042]
Thus, in the present embodiment, in the in-side gate valve 9, the closed state, the state in which the small-diameter port 92c is opened, and the state in which the large-diameter port 91b are opened are sequentially repeated. Is limited.
Therefore, the high pressure of the master cylinder MC is not directly transmitted to the pump 4, and the deterioration of the durability of the seal members 45, 46, etc. of the pump 4 is prevented, and the flow rate of the pump 4 is secured and active braking is performed. Control can continue and does not adversely affect active braking control.
Incidentally, when the master cylinder pressure generated by the driver's braking operation becomes higher than the pressure formed by the active braking control, the one valve 3a provided in parallel with the out-side gate valve 3 opens, and the wheel Brake fluid is supplied to the cylinder. As a result, when the wheel cylinder pressure is higher than the control target, active pressure reduction is performed as shown in FIG. 6A (at time t3). Thus, the master cylinder pressure generated by the driver's braking operation is transmitted to the wheel cylinder. Therefore, even if the suction amount in the pump 4 is reduced by the high pressure transmission prevention control, the active braking control is performed. There is no adverse effect.
[0043]
In addition, since the valve body 93 that is operated by driving the solenoid uses only a two-stage valve as the in-side gate valve 9 so as to open the small-diameter opening 92c, the driver performs a braking operation. Even if a high-pressure master cylinder is generated, the force that this high pressure acts on the valve body in the valve closing direction is small, so that the valve can be opened by a low-power solenoid, and the device can be downsized. Can be planned.
[0044]
Furthermore, in the first embodiment, when the high pressure transmission prevention control is executed, the duty ratio of the drive signal output to the in-side gate valve 9 is changed according to the estimated master cylinder pressure.
That is, the higher the estimated master cylinder pressure, the higher the duty ratio.
Therefore, according to the master cylinder pressure, it is possible to achieve a high level of balance between prevention of transmission of high pressure in the in-side gate valve 9 and securing of a necessary flow rate.
[0045]
(Embodiment 2)
[0046]
  next, RealEmbodiment 2 will be described. In the second embodiment, in addition to the high-pressure transmission prevention control described in the first embodiment, a transmission prevention standby control is executed. When the ON signal of the brake switch is detected, the above-described high voltage transmission prevention control is executed. However, only the transmission prevention standby control may be executed without performing this high voltage transmission prevention control.
Since the difference between the second embodiment and the first embodiment is only the part that executes the transmission prevention standby control, only the transmission prevention standby control will be described below.
[0047]
FIG. 7 is a flowchart showing a flow of transmission prevention standby control executed by the control unit.
This transmission prevention standby control is started by executing active braking control.
[0048]
In step 501, it is determined whether or not active braking control is being performed. If active braking control is being performed, the process proceeds to step 502. Otherwise, transmission prevention standby control is terminated.
[0049]
In step 502, the first counter τ₁Count up.
[0050]
In step 503, the first counter τ₁Is the predetermined time t₀If it has passed, the process proceeds to step 503, otherwise the first counter τ₁Continue counting up.
[0051]
In step 504, a drive signal having a preset duty ratio is output toward the in-side gate valve 9. The duty ratio of the drive signal is set to such a degree that the opening / closing operation can be performed even if the master cylinder pressure is very high.
[0052]
In step 505, the second counter τ₂Start counting up.
[0053]
In step 506, the second counter τ₂Is the predetermined time t₁The process proceeds to step 507 if it has elapsed, otherwise the second counter τ₂Continue counting up.
[0054]
In step 507, the drive signal is stopped.
[0055]
In step 508, the first counter τ₁And the second counter τ₂To reset.
[0056]
In the brake control device according to the second embodiment, when the control unit executes the active braking control, the control unit executes the transmission prevention standby control in parallel with the active braking control so that the in-side gate valve 9 has a predetermined duty ratio. A drive signal is output.
[0057]
FIG. 8 is a time chart showing the operating state at this time. Originally, the in-side gate valve 9 is opened at the time of active braking control. In the second embodiment, as shown in FIG. A valve closing signal is periodically output to the in-side gate valve 9. That is, active braking control is started at t1, and the driver does not operate the brake pedal at this time, and the master cylinder pressure does not become high, so that the large-diameter port 91b is selected as the flow path of the in-side gate valve 9. Yes.
[0058]
At this time, the first counter τ₁Count up is started, and at time t2, a predetermined time t has elapsed since the start of active braking control.₀When elapses, a drive command to the in-side gate valve 9 is output regardless of the state of the master cylinder pressure. As a result, the in-side gate valve 9 is closed while the drive command is being output. At this time, the second counter τ₂When the predetermined time t1 has elapsed since the drive command to the in-side gate valve 9 is output at time t3, the drive command to the in-side gate valve 9 ends and the first counter τ₁And the second counter τ₂Is reset, and steps 501 to 508 are repeated again.
[0059]
When the master cylinder pressure starts to increase due to the driver's brake pedal operation at time t4, a high pressure is supplied to the in-side gate valve 9. At this time, at time t5, the in-side gate valve 9 is temporarily closed by a periodic drive signal to the in-side gate valve 9. At this time, since the high pressure is supplied to the in-side gate valve 9 from the master cylinder side, the high-pressure acts on the small-diameter plug 92 as described above, the large-diameter port 91b is closed, and again at time t6. When the drive command is canceled, the small-diameter opening 92c is in an open state. As a result, the supply pressure to the pump 4 does not increase with the increase in the master cylinder pressure and is switched to the small diameter port 92c, thereby preventing an excessive pressure supply.
[0060]
  In this way, even if the sensor that detects the master cylinder pressure is not provided, for example, by performing the transmission prevention standby control that performs the operation of opening and closing the in-side gate valve 9 instantaneously, When the master cylinder pressure is applied, the large diameter port 91b and the small diameter port 92c are automatically switched, and the flow rate of the suction circuit is reduced by a predetermined amount. Therefore, even if the driver suddenly and strongly performs the braking operation, it is possible to prevent the high pressure from being continuously transmitted to the pump 4.The
[0061]
  Furthermore, in addition to the transmission prevention standby control, the high pressure transmission prevention control described in the first embodiment is executed. Therefore, during active braking control, the in-side gate valve 9 is activated in advance by the transmission prevention standby control. As a result, the responsiveness of the in-side gate valve 9 is improved when the high-pressure transmission prevention control is executed in response to the driver performing a braking operation. In addition, even if there is a response delay in the execution of the high pressure transmission prevention control with respect to the driver's braking operation, the transmission prevention standby control can suppress a sudden transmission of the master cylinder pressure. Can reliably prevent high-pressure transmission toThe
[Brief description of the drawings]
FIG. 1 is a brake piping diagram illustrating a brake control device according to an embodiment.
FIG. 2 is an enlarged sectional view showing a pump according to the embodiment.
FIG. 3 is an enlarged cross-sectional view illustrating an in-side gate valve according to the embodiment.
FIG. 4 is a block diagram illustrating a control configuration of brake control according to the embodiment.
FIG. 5 is a flowchart showing high-pressure transmission prevention control during active braking control according to the embodiment.
FIG. 6 is a time chart showing high-pressure transmission prevention control of the embodiment.
FIG. 7 is a flowchart illustrating transmission prevention standby control during active braking control according to the embodiment.
FIG. 8 is a time chart showing transmission prevention standby control in the embodiment.
[Explanation of symbols]
1 Brake piping
2 Brake piping
3 Out side gate valve
3a One-way valve
4 Pump
4a, 4b Inhalation circuit
4c Discharge circuit
4d check valve
4p, 4p plunger
4r pump room
5 Inlet valve
6 Outflow valve
7 Reservoir
8 Motor
9 Inn side gate valve
10 Return passage
12 Wheel speed sensor
13 Brake switch
14 Front and rear G sensor
41 Through hole
42 Suction valve
43 plug
44 Discharge valve
45,46 Seal member
51 Bypass circuit
52 One-way valve
90 cylinders
90a Tube member
91 Large-diameter plug
91b Large-diameter mouth
91a Large-diameter communication hole
92a Plug spring
92 Small diameter plug
92c small diameter opening
92b Small-diameter communication hole
92d flow path
93 Disc
93a Valve spring
93b groove
94 plug
BP Brake pedal
H / U Brake unit
MC master cylinder
RES reservoir
WC Wheel cylinder

Claims (5)

A brake circuit for supplying pressure generated in the master cylinder to the wheel cylinder;
A pump that sucks the brake fluid of the master cylinder through a suction circuit provided in parallel with the brake circuit, and discharges the brake fluid to the brake circuit through a discharge circuit;
Pressure adjusting means provided in the brake circuit, for adjusting the discharge pressure of the pump and supplying the pressure to the wheel cylinder;
An in-side gate valve provided in the middle of the suction circuit to open and close the suction circuit;
A control unit for controlling the operation of the in-side gate valve, the pressure adjusting means and the pump, based on an input of a detecting means for detecting a running state;
With
The control unit opens the in-side gate valve and operates the pump to release the brake fluid from the master cylinder when the control unit determines that the braking force is necessary according to the driving state regardless of the driver's braking operation. In a brake control device configured to execute active braking control that supplies a brake circuit, adjusts pressure by a pressure adjusting means, and supplies the wheel cylinder to actively generate a braking force.
If the driver's braking operation is not detected during the active braking control, the control unit executes transmission prevention standby control for opening and closing the in-side gate valve at a predetermined interval, and the driver's braking operation is detected. And a brake control device that closes the in-side gate valve . The brake control device according to claim 1, wherein
When the driver starts a braking operation during execution of active braking control, the control unit outputs a drive signal having a predetermined opening / closing duty ratio to the in-side gate valve to limit the flow rate in the suction circuit. A brake control device characterized in that high pressure transmission prevention control is executed. The brake control device according to claim 2 ,
The in-side gate valve is arranged in the middle of the suction circuit and has a large-diameter plug having a large-diameter port that can obtain the required maximum flow rate of the pump, and is provided in series with the large-diameter plug to open and close the large-diameter port. And a small-diameter plug having a small-diameter port smaller in diameter than the large-diameter port in series with the large-diameter port, a valve body that opens and closes the small-diameter port, and a biasing means for plug that biases the small-diameter plug in the valve opening direction. A valve body urging means for urging the valve body in either the valve closing direction or the valve opening direction; and a valve for applying a suction force against the urging force of the valve body urging means. A brake control device having a two-stage valve structure having a solenoid for closing or opening a body . In the brake control device according to claim 2 or 3 ,
A master cylinder pressure detecting means for obtaining a master cylinder pressure is provided as an input means of the control unit,
In accordance with the detected master cylinder pressure, the control unit is configured to execute control so that the duty ratio of the drive signal in the high pressure transmission prevention control is such that the higher the master cylinder pressure, the higher the valve closing ratio. Brake control device. The brake control device according to claim 4 , wherein
A brake control device using a means for estimating a master cylinder pressure based on a longitudinal acceleration of a vehicle and a wheel speed as the master cylinder pressure detecting means .

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