WO2012157050A1

WO2012157050A1 - Vehicle braking device

Info

Publication number: WO2012157050A1
Application number: PCT/JP2011/061107
Authority: WO
Inventors: 山田　芳久; 洋司溝口; 聡宇▲高▼
Original assignee: トヨタ自動車株式会社
Priority date: 2011-05-13
Filing date: 2011-05-13
Publication date: 2012-11-22

Abstract

The present invention is provided with: a hydraulic path for a first system; a hydraulic path for a second system; a first hydraulic pressure source that generates hydraulic pressure supplied to the wheel cylinder of a first wheel; a first valve that varies the wheel cylinder pressure of the first wheel; a second hydraulic pressure source that generates hydraulic pressure supplied to the wheel cylinder of a second wheel by means of the hydraulic path for the second system; a second valve that varies the wheel cylinder pressure of the second wheel; a third hydraulic pressure source that generates hydraulic pressure in accordance with the operation of a brake pedal by a driver; and a control device that executes emergency braking control wherein, when a predetermined emergency deceleration is called for, controls the first valve and the second valve via differing embodiments, and on the basis of the hydraulic pressure generated by the first hydraulic pressure source and the second hydraulic pressure source, increases the wheel cylinder pressure of the first wheel and the wheel cylinder pressure of the second wheel.

Description

Braking device for vehicle

The present invention relates to a braking device for a vehicle including a first system and a second system hydraulic circuit.

Conventionally, when manual braking (normal braking) and automatic braking are performed at the same time, it is generated in the wheel cylinder by adding an assist pressure corresponding to the collision danger level indicating the degree of danger of colliding with an obstacle to the master cylinder pressure. The technique to make is known (for example, refer patent document 1).

Japanese Patent No. 4415617

By the way, in collision avoidance control and the like, when emergency deceleration is necessary, automatic braking may be performed without performing normal braking. However, since the oil supply path is different between the normal brake and the automatic brake, there may be a difference in the pressure increase mode of the hydraulic pressure between the systems due to the difference in the pressure increase resistance of the orifice. Further, in the case of the automatic brake, in the case of the front and rear pipes, the pressure increase of the large capacity caliper is delayed and it is likely to become the rear preceding brake. For this reason, at the time of automatic braking, there is a problem that the rear wheel tends to be locked and vehicle stability may be deteriorated. Further, in the case of X piping, there is a problem in that the left and right brake distributions are different, and a sudden vehicle deflection may occur during automatic braking.

Therefore, an object of the present invention is to provide a vehicle braking device that can appropriately increase the hydraulic pressure for each system during automatic braking when emergency deceleration is required.

According to one aspect of the present invention, a first system hydraulic circuit that supplies hydraulic pressure to a wheel cylinder of a first wheel of a vehicle;
A second hydraulic circuit for supplying hydraulic pressure to the wheel cylinder of the second wheel of the vehicle;
A first hydraulic pressure generating source that is provided in the hydraulic circuit of the first system and generates hydraulic pressure supplied to the wheel cylinder of the first wheel by the hydraulic circuit of the first system;
A first valve provided in the hydraulic circuit of the first system and configured to vary a wheel cylinder pressure of the first wheel;
A second hydraulic pressure generating source that is provided in the second hydraulic circuit and generates hydraulic pressure supplied to the wheel cylinder of the second wheel by the second hydraulic circuit;
A second valve provided in the hydraulic circuit of the second system and configured to vary a wheel cylinder pressure of the second wheel;
A third hydraulic pressure generating source that is connected to the hydraulic circuit of the first system and the hydraulic circuit of the second system, and generates hydraulic pressure according to the operation of the brake pedal of the driver;
A control device that executes emergency braking control independent of the driver's operation of the brake pedal when a predetermined emergency deceleration is requested,
In the emergency braking control, the control device controls the first valve and the second valve in different modes, and based on the hydraulic pressure generated by the first hydraulic pressure generation source and the second hydraulic pressure generation source. The vehicle brake device is characterized in that the wheel cylinder pressure of the first wheel and the wheel cylinder pressure of the second wheel are respectively increased by the hydraulic circuit of the first system and the hydraulic circuit of the second system. Is done.

According to the present invention, it is possible to obtain a vehicular braking apparatus that can appropriately increase the hydraulic pressure for each system during automatic braking when emergency deceleration is required.

1 is a schematic configuration diagram showing a main configuration of a vehicle braking device 1 according to an embodiment of the present invention and a main part of a vehicle 102 on which the vehicle braking device 1 is mounted. It is a figure which shows an example of the hydraulic circuit 200 by front and rear piping. FIG. 3 is a diagram schematically showing the flow of oil when the

pumps

260F and 260R in the hydraulic circuit 200 shown in FIG. 2 are operated. It is explanatory drawing of operation | movement of the M / C cut valve 206F. 3 is a flowchart illustrating an example of hydraulic control executed by the control device 10 in a hydraulic circuit 200 using front and rear piping. It is a figure which shows typically an example of the pressure increase suppression method with respect to a rear-wheel system, and is a figure which shows an example of the time series of the target control value set with respect to each of a front-wheel system and a rear-wheel system. It is a figure which shows the simultaneous series by the comparative example which applies the same (common) target control value with respect to a front-wheel system and a rear-wheel system. It is a characteristic view which shows an example of the relationship between a wheel cylinder pressure and oil consumption. It is a characteristic view showing an example of the relationship of the discharge oil amount with respect to the time of the pump 260F in the front wheel system hydraulic circuit 201F. It is a figure which shows another example of the time series (target control value pattern) of the target control value set with respect to each of a front-wheel system and a rear-wheel system. 5 is a flowchart showing another example of hydraulic control executed by the control device 10. It is a figure which shows an example of each map 1, 2, 3 used by the process shown in FIG. It is a figure which shows an example of the hydraulic circuit 200 'by X piping. 4 is a flowchart illustrating an example of hydraulic control executed by the control device 10 in a hydraulic circuit 200 ′ using X piping. It is a figure which shows an example of the time series (target control value pattern) of the target control value set with respect to each of the 1st system hydraulic circuit 201A and the 2nd system hydraulic circuit 201B. It is a figure which shows the simultaneous series by the comparative example which applies the same (common) target control value with respect to 201 A of 1st system hydraulic circuits, and the 2nd system hydraulic circuit 201B. It is a figure which shows an example of the relationship between a vehicle body speed and a wheel speed. It is a figure which shows an example of the relationship between a slip ratio and braking force.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a main configuration of a vehicle braking device 1 according to an embodiment of the present invention and a main part of a vehicle 102 on which the vehicle braking device 1 is mounted.

1, 100FL and 100FR respectively indicate left and right front wheels of the vehicle 102, and 100RL and 100RR respectively indicate left and right rear wheels that are driving wheels of the vehicle. The left and right front wheels 100FL and 100FR may be steered via tie rods by a power steering device that is driven in response to steering of the steering wheel.

The vehicle braking device 1 includes a control device 10 and a hydraulic circuit 200. The braking force of each wheel 100FR, 100FL, 100RR, 100RL is generated by the hydraulic pressure supplied to the wheel cylinders 224FR, 224FL, 224RR, 224RL by the hydraulic circuit 200, respectively. The hydraulic circuit 200 is provided with a master cylinder 202. The master cylinder 202 generates hydraulic pressure to be supplied to the wheel cylinders 224FR, 224FL, 224RR, 224RL in response to the depression operation of the brake pedal 190 by the driver.

The control device 10 may be configured by an ECU (electronic control unit) including a microcomputer. The function of the control device 10 may be realized by any hardware, software, firmware, or a combination thereof. For example, any part or all of the functions of the control device 10 may be applied to an application-specific ASIC (application-specific).
integrated circuit), FPGA (Field Programmable Gate)
Array) or a DSP (digital signal processor). Further, the function of the control device 10 may be realized in cooperation with a plurality of ECUs.

The front radar sensor 134 is connected to the control device 10. The front radar sensor 134 detects the state of a front obstacle (typically, the front vehicle) in front of the vehicle using radio waves (for example, millimeter waves), light waves (for example, lasers), or ultrasonic waves as detection waves. The front radar sensor 134 detects information indicating a relationship between the front obstacle and the own vehicle, for example, a relative speed, a relative distance, and an azimuth (lateral position) of the front obstacle based on the own vehicle at a predetermined cycle. When the front radar sensor 134 is a millimeter wave radar sensor, the millimeter wave radar sensor may be, for example, an electronic scan type millimeter wave radar. In this case, the front obstacle is detected using the Doppler frequency (frequency shift) of the radio wave. The relative speed of the front obstacle is detected using the delay time of the reflected wave, and the direction of the front obstacle is detected based on the phase difference of the received wave among the plurality of receiving antennas. These detection data are transmitted to the control device 10 at a predetermined cycle.

The control device 10 is connected with wheel speed sensors 138FR, 138FL, 138RR, 138RL arranged on each wheel of the vehicle. The wheel speed sensors 138FR, 138FL, 138RR, 138RL may be active sensors or passive sensors. The control device 10 is connected to an acceleration sensor 136 that detects acceleration in the vehicle longitudinal direction generated in the vehicle. The acceleration sensor 136 is attached, for example, under the center console of the vehicle. The acceleration sensor 136 includes an acceleration sensor unit that outputs a signal corresponding to the acceleration in the vehicle longitudinal direction or the vehicle width direction that occurs in the mounted vehicle, and a yaw rate sensor unit that outputs a signal corresponding to the angular velocity generated around the center of gravity axis of the vehicle. May be realized by a semiconductor sensor.

The hydraulic circuit 200 is connected to the control device 10. The control device 10 controls the braking force of each wheel 100FL, 100FR, 100RL, 100RR by controlling various valves (described later) provided in the hydraulic circuit 200. The control method by the control device 10 will be described in detail later.

FIG. 2 is a diagram showing an example of a hydraulic circuit 200 using front and rear piping.

The hydraulic circuit 200 shown in FIG. 2 includes two systems of

hydraulic circuits

201F and 201R. In the illustrated example, the two

hydraulic circuits

201F and 201R are composed of front and rear pipes that are divided into systems of front wheels 100FL and 100FR and rear wheels 100RL and 100RR. Hereinafter, the hydraulic circuit 201F is referred to as a front wheel system hydraulic circuit 201F, and the hydraulic circuit 201R is referred to as a rear wheel system hydraulic circuit 201R. In FIG. 2, a portion 220 surrounded by a two-dot chain line may be embodied as a brake actuator.

The master cylinder 202 has a first master cylinder chamber 202F and a second master cylinder chamber 202R defined by free pistons (not shown) urged to predetermined positions by compression coil springs on both sides thereof. is doing.

First, the front wheel system hydraulic circuit 201F will be described. One end of a front wheel master passage 204F is connected to the first master cylinder chamber 202F. The other end of the front wheel master passage 204F is connected to a master cylinder cut solenoid valve 206F (hereinafter referred to as an M / C cut valve 206F). The M / C cut valve 206F is a normally open valve that is open when not controlled. The M / C cut valve 206F has a function of regulating the hydraulic pressure generated by the pump 260F by controlling the open / closed state of the M / C cut valve 206F by the control device 10. The opening degree of the M / C cut valve 206F can be controlled linearly, and a control hydraulic pressure corresponding to the opening degree is generated.

A flow path 205F is connected between the M / C cut valve 206F and the master cylinder 202 in the front wheel master passage 204F. The channel 205F communicates with the reservoir 250F. One end of a pump flow path 210F is connected to the reservoir 250F. The other end of the pump channel 210F is connected to the high-pressure channel 208F. A pump 260F and a check valve 262F are provided in the pump flow path 210F. The discharge side of the pump 260F is connected to the high pressure flow path 208F via a check valve 262F. The pump 260F is driven by, for example, a motor (not shown). The pump 260F is controlled by the control device 10. Pump 260F may be of any type including a piston type. For example, although not shown, the pump 260F may include a camshaft that is eccentric with respect to the rotation shaft of the motor, and a piston in a cylinder that is disposed along the outer periphery of the camshaft. In this configuration, the piston in the cylinder reciprocates when the camshaft rotates due to the rotation of the motor, sucks oil when moving to the center side, and pressurizes oil when moving to the outer periphery side. Is discharged. During operation, the pump 260F pumps oil from the reservoir 250F and pumps the oil to the high-pressure channel 208F by the pump channel 210F via the check valve 262F (see FIG. 3). The hydraulic circuit 200 does not include an accumulator that stores high-pressure oil discharged from the pump 260F.

The high pressure flow path 208F communicating with the wheel cylinders 224FL and 224FR is connected to the M / C cut valve 206F. The high-pressure channel 208F branches into two and communicates with the wheel cylinders 224FL and 224FR. In each flow path portion after branching, holding solenoid valves 212FL and 212FR are respectively provided, and pressure reducing solenoid valves 214FL and 214FR are respectively provided. Holding solenoid valves 212FL and 212FR are normally open valves that are open when not controlled. The open / close state of the holding solenoid valves 212FL and 212FR is controlled by the control device 10. The decompression solenoid valves 214FL and 214FR are normally closed valves that are closed when not controlled. The controller 10 controls the open / close state of the decompression solenoid valves 214FL and 214FR. The decompression solenoid valves 214FL and 214FR are connected to the reservoir 250F via the decompression passage 216F.

Next, the rear wheel system hydraulic circuit 201R will be described. One end of a rear wheel master passage 204R is connected to the second master cylinder chamber 202R. A master cylinder pressure sensor 265 is provided in the rear wheel master passage 204R. The master cylinder pressure sensor 265 outputs a signal corresponding to the master cylinder pressure generated in the master passage 204R. The output signal of the master cylinder pressure sensor 265 is supplied to the control device 10.

The other end of the rear wheel master passage 204R is connected to a master cylinder cut solenoid valve 206R (hereinafter referred to as an M / C cut valve 206R). The M / C cut valve 206R is a normally open valve that is open when not controlled. The M / C cut valve 206R has a function of regulating the hydraulic pressure generated by the pump 260R by controlling the open / close state of the M / C cut valve 206R by the control device 10. The opening degree of the M / C cut valve 206R can be controlled linearly, and a control hydraulic pressure corresponding to the opening degree is generated.

A flow path 205R is connected between the M / C cut valve 206R and the master cylinder 202 in the rear wheel master passage 204R. The flow path 205R communicates with the reservoir 250R. One end of a pump flow path 210R is connected to the reservoir 250R. The other end of the pump flow path 210R is connected to the high pressure flow path 208R. A pump 260R and a check valve 262R are provided in the pump flow path 210R. The discharge side of the pump 260R is connected to the high-pressure channel 208R via a check valve 262R. The pump 260R is driven by, for example, a motor (not shown). This motor may be the same as the motor that drives the pump 260F for the front wheels. The pump 260R is controlled by the control device 10. During operation, the pump 260R pumps oil from the reservoir 250R and pumps the oil to the high-pressure channel 208R through the pump channel 210R via the check valve 262R (see FIG. 3). The hydraulic circuit 200 does not include an accumulator that stores high-pressure oil discharged from the pump 260R.

The M / C cut valve 206R is connected to a high pressure flow path 208R communicating with the wheel cylinders 224RL and 224RR. The high-pressure channel 208R branches into two and communicates with the wheel cylinders 224RL and 224RR. In each flow path portion after branching, holding solenoid valves 212RL and 212RR are provided, and pressure reducing solenoid valves 214RL and 214RR are provided. Holding solenoid valves 212RL and 212RR are normally open valves that are open when not controlled. The open / close state of the holding solenoid valves 212RL and 212RR is controlled by the control device 10. The decompression solenoid valves 214RL and 214RR are normally closed valves that are closed when not controlled. The open / close state of the decompression solenoid valves 214RL and 214RR is controlled by the control device 10. The decompression solenoid valves 214RL and 214RR are connected to the reservoir 250R via the decompression passage 216R.

Here, in the state shown in FIG. 2, each valve (M /

C cut valves

206F, 206R, holding solenoid valves 212FL, 212FR, 212RL, 212RR, and pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR) is in the non-control position. The

pumps

260F and 260R are in a non-operating state. Thus, the pressure in the first master cylinder chamber 202F is supplied to the wheel cylinders 224FL and 224FR, and the pressure in the second master cylinder chamber 202R is supplied to the wheel cylinders 224RL and 224RR. Therefore, during normal braking, the pressure in the wheel cylinder of each wheel, that is, the braking force, is increased or decreased according to the operation amount (depression force) of the brake pedal 190.

Next, the flow of oil will be described when the

pumps

260F and 260R are operated.

FIG. 3 is a diagram schematically showing the oil flow when the

pumps

260F and 260R in the hydraulic circuit 200 shown in FIG. 2 are operated. Hereinafter, the flow of oil when the pump 260F is operated in the front wheel system hydraulic circuit 201F will be described. However, the operation of the pump 260R is substantially the same as the operation of the pump 260F.

When the pump 260F is operated, the oil in the reservoir 250F flowing in from the master cylinder 202 via the flow path 205F is pumped to the high pressure flow path 208F by the pump flow path 210F via the check valve 262F. When the holding solenoid valves 212FL and 212FR are in the open position, this oil is supplied to the wheel cylinders 224FL and 224FR from the high pressure passage 208F, and the pressure in the wheel cylinders 224FL and 224FR (wheel cylinder pressure) is increased. In the state shown in the figure, the pressure reducing solenoid valves 214FL and 214FR are in the closed position, and the wheel cylinder pressure is increased. When the pressure reducing solenoid valves 214FL and 214FR are opened from this state, oil flows into the reservoir 250F through the pressure reducing passage 216F, and the wheel cylinder pressures of the wheel cylinders 224FL and 224FR are reduced. On the other hand, when the holding solenoid valves 212FL and 212FR are closed in the illustrated state, the wheel cylinder pressures of the wheel cylinders 224FL and 224FR are held.

Also, the oil pumped to the high pressure channel 208F flows to the master passage 204F via the M / C cut valve 206F. The flow rate of this oil changes according to the open / closed state (opening degree) of the M / C cut valve 206F (see FIG. 4).

As described above, when the

pumps

260F and 260R are operated, the pressures pumped up by the pump 260F are supplied to the wheel cylinders 224FL and 224FR, and the pressures pumped up by the pump 260R are supplied to the wheel cylinders 224RL and 224RR. As a result, the braking pressure of each wheel is independent of the amount of operation of the brake pedal 190 (the M /

C cut valves

206F and 206R, the holding solenoid valves 212FL, 212FR, 212RL, 212RR, and the pressure reducing solenoid). The valve 214FL, 214FR, 214RL, 214RR) can be controlled according to the operating state.

Next, the operation of the M /

C cut valves

206F and 206R will be described.

4A and 4B are explanatory diagrams of the operation of the M / C cut valve 206F. FIG. 4A shows a state in which the opening degree of the M / C cut valve 206F is relatively small, and FIG. 4B shows the M / C cut valve 206F. The state where the opening degree of 206F is smaller is shown. The operation of the M / C cut valve 206R may be the same.

In the illustrated example, the M / C cut valve 206F has a valve element 274 disposed in the valve chamber 270 so as to be able to reciprocate. The valve chamber 270 is connected to a front wheel master passage 204F from the master cylinder 202 and a high pressure passage 208F communicating with the wheel cylinders 224FR and 224FL via an internal passage 278 and a port 280. A solenoid 282 is disposed around the valve element 274, and the valve element 274 is urged to a valve opening position by a compression coil spring 284. When a drive voltage is applied to the solenoid 282, the valve element 274 is biased against the port 280 against the spring force of the compression coil spring 284.

As shown in FIG. 4, when the opening degree of the M / C cut valve 206F decreases, the oil pumped from the pump 260F to the high pressure flow path 208F flows to the master passage 204F via the M / C cut valve 206F. Less oil. Thereby, a large wheel cylinder pressure can be generated in the wheel cylinders 224FL and 224FR. In this way, the control device 10 controls the magnitude of the applied current (differential pressure instruction value) to the solenoid 282 of the M / C cut valve 206F, so that the hydraulic pressure in the high-pressure flow path 208F (in the master passage 204F) is controlled. The differential pressure between the hydraulic pressure and the hydraulic pressure in the high-pressure channel 208F can be controlled. In the illustrated example, the M / C cut valve 206F incorporates a check valve 286 that allows only the flow of oil from the valve chamber 270 toward the high-pressure channel 208F.

Next, the hydraulic control executed by the control device 10 when a predetermined emergency deceleration is requested, and the hydraulic control in the hydraulic circuit 200 using the front and rear piping will be described.

FIG. 5 is a flowchart showing an example of hydraulic control executed by the control device 10. The processing routine shown in FIG. 5 may be repeatedly executed at predetermined intervals while the vehicle is traveling.

In step 500, the control device 10 determines a sudden braking command start condition. The sudden braking command start condition may be satisfied when a predetermined emergency deceleration is requested. For example, in the collision avoidance control with the front obstacle, the time until the collision with the front obstacle: TTC (Time
to Collation), and may be satisfied when the calculated TTC falls below a predetermined value (for example, 1 second). In this case, the control device 10 calculates a TTC for a front obstacle in a predetermined direction (lateral position) based on the detection result from the front radar sensor 134, and the calculated TTC calculates a predetermined value (for example, 1 second). If so, go to Step 502. Note that the TTC may be derived by dividing the relative distance to the front obstacle by the relative speed with respect to the front obstacle. In the automatic driving control, for example, it may be satisfied when the magnitude of the deceleration required to maintain a predetermined lower distance between the vehicle ahead and the vehicle ahead exceeds a predetermined value. Note that the sudden braking command start condition may not be satisfied in the automatic driving control but may be satisfied only in the collision avoidance control. If the sudden braking command start condition is satisfied, the process proceeds to step 502. Otherwise, the process ends.

In step 502, the control device 10 executes a four-wheel automatic brake in which the pressure increase by the rear wheel system hydraulic circuit 201R is suppressed based on the target control value. Specifically, the control device 10 operates the

pumps

260F and 260R and controls the M /

C cut valves

206F and 206R to increase the wheel cylinder pressures of the wheel cylinders 224FL, 224FR, 224RL and 224RR. At this time, the control device 10 controls the M /

C cut valves

206F and 206R so that the wheel cylinder pressures of the rear wheel cylinders 224RL and 224RR do not exceed the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR. To control. The pressure increase suppression for the rear wheel system can be realized in a wide variety of modes, and may be realized in any mode. For example, with respect to the pressure increase start timing toward the hydraulic target value, the pressure increase start timing by the rear wheel system hydraulic circuit 201R may be delayed by a predetermined delay time ΔT with respect to the pressure increase start timing by the front wheel system hydraulic circuit 201F. Other specific examples of the method for suppressing pressure increase with respect to the rear wheel system will be described later.

The target control value may be set for any physical quantity related to the wheel cylinder pressure of the wheel. For example, the target control value may be a target deceleration, a hydraulic target value for the wheel cylinder pressure, a target value of a pressure increase gradient for the wheel cylinder pressure, or M / It may be a target value of a differential pressure instruction value (applied current value) for the

C cut valves

206F and 206R. The target control value may be a fixed value or a variable value set according to a relative relationship (such as TTC) with the front obstacle. In the case of a fixed value, the target control value may be, for example, a target deceleration of 6.0 m / s ² or a hydraulic target value for each wheel cylinder pressure of 5 Mpa.

In step 504, the control device 10 determines a sudden braking command end condition. The sudden braking command end condition is, for example, when a collision is detected based on the acceleration sensor 136 or the like, when the vehicle body speed becomes 0 km / h, or when the TTC exceeds 1.5 [seconds], May be satisfied when it continues for a predetermined time (for example, 3 seconds) or longer. If the sudden braking command termination condition is satisfied, the routine ends. Otherwise, the process returns to step 502.

It should be noted that the four-wheel automatic braking in step 502 is typically executed in a situation where the driver does not operate the brake pedal 190. That is, the target control value used in step 502 is a value (including a fixed value) determined based on factors other than the operation amount of the brake pedal 190. If the driver operates the brake pedal 190 (for example, detected based on the pedaling force switch 192) after starting the four-wheel automatic braking, the operation of the brake pedal 190 is ignored and the four-wheel automatic braking is performed. May be continued. Alternatively, when the driver operates the brake pedal 190 after starting the four-wheel automatic braking, for example, when the master cylinder pressure becomes equal to or higher than a predetermined pressure, the normal braking may be performed. Alternatively, although not possible with the configuration of the hydraulic circuit 200 shown in FIG. 2, when other hydraulic circuit configurations are possible, the wheel cylinders 224FL, 224FR are added by adding both hydraulic pressures (or selecting the larger one). It is good also as applying to 224RL and 224RR.

However, the four-wheel automatic braking in step 502 may be executed under a situation where the driver is operating the brake pedal 190. In this case, the sudden braking command start condition may be varied depending on whether the driver operates the brake pedal 190 or not. For example, when there is an operation of the brake pedal 190 by the driver, the TTC as a threshold value that satisfies the sudden braking command start condition may be changed to a long time (for example, 1.5 seconds). In any case, when the four-wheel automatic brake is started, the operation of the brake pedal 190 may be ignored thereafter. That is, the target control value used in step 502 may be determined based on factors other than the operation amount of the brake pedal 190. Alternatively, as described above, when the driver still operates the brake pedal 190 after starting the four-wheel automatic braking, for example, when the master cylinder pressure becomes a predetermined pressure or more, the process shifts to the normal brake. However, if the hydraulic circuit 200 shown in FIG. 2 is not possible, other hydraulic circuit configurations can be used. ) It may be applied to the wheel cylinders 224FL, 224FR, 224RL, 224RR.

In the four-wheel automatic brake in step 502, the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR are all maintained in the normal state. That is, the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR are VSC (Vehicle
In the vehicle stabilization control such as Stability Control), each wheel is individually controlled. However, the four-wheel automatic brake in step 502 is control for each system, and different control is not executed in the same system. However, after the start of the four-wheel automatic braking in step 502, the ABS (anti-lock)
vehicle stabilization control such as a brake system) or VSC may be activated. In this case, the four-wheel automatic brake may be stopped, or such other control may be executed while continuing the four-wheel automatic brake. In the latter case, the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR are controlled while performing the same control as the M /

C cut valves

206F, 206R during the four-wheel automatic braking. It is good also as performing control according to the control law of ABS or vehicle stabilization control.

Next, a specific example of the pressure increase suppression method for the rear wheel system that may be employed in step 502 shown in FIG. 5 will be described.

FIG. 6 is a diagram showing an example of a time series (target control value pattern) of target control values set for each of the front wheel system and the rear wheel system. Here, as an example, the target control value is a hydraulic target value for the wheel cylinder pressure. In FIG. 6, the time series of the hydraulic target value (front hydraulic target value) with respect to the wheel cylinder pressure of the front wheel cylinders 224FL, 224FR, and the hydraulic target value (rear hydraulic target) with respect to the wheel cylinder pressure of the rear wheel wheel cylinders 224RL, 224RR. Value) is indicated by a dotted line, and the time series of the actual wheel cylinder pressures (front actual hydraulic pressure) of the front wheel cylinders 224FL and 224FR when controlled by these hydraulic target value patterns and the actual The time series of the wheel cylinder pressures (rear actual hydraulic pressure) of the rear wheel wheel cylinders 224RL and 224RR are shown by solid lines.

In the example shown in FIG. 6, the rise timing of the rear hydraulic target value is delayed by a predetermined delay time ΔT from the rise timing of the front hydraulic target value. Specifically, the front hydraulic pressure target value increases toward the final front hydraulic pressure target value (5 Mpa in this example) at the start of the sudden braking command. On the other hand, the rear hydraulic pressure target value increases toward the final rear hydraulic pressure target value (5 Mpa in this example) after a predetermined delay time ΔT from the start of the sudden braking command. The final target value (the final front hydraulic pressure target value and the final rear hydraulic pressure target value) may correspond to a target control value that should be finally realized by the four-wheel automatic brake.

FIG. 7 is a diagram showing a simultaneous sequence according to a comparative example in which the same (common) target control value is applied to the front wheel system and the rear wheel system. In this comparative example, both the front hydraulic pressure target value and the rear hydraulic pressure target value increase toward the final hydraulic pressure target value (5 Mpa in this example) at the start of the sudden braking command. In such a configuration, due to the characteristic difference between the rear wheel system hydraulic circuit 201R and the front wheel system hydraulic circuit 201F, as shown by the solid lines attached to the front actual hydraulic pressure and the rear actual hydraulic pressure in FIG. The wheel cylinder pressures of the wheel cylinders 224RL and 224RR exceed the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR. More specifically, the front wheel system hydraulic circuit 201F has a significantly larger capacity of the front caliper than the rear caliper, so that the consumed oil required to generate the same oil pressure as the rear wheel system hydraulic circuit 201R. The amount increases (see FIG. 8). Therefore, in this comparative example, during four-wheel automatic braking, the wheel cylinder pressures of the rear wheel cylinders 224RL and 224RR increase before the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR, and the rear wheel lock tendency Become.

On the other hand, in the example shown in FIG. 6, the rising timing of the rear hydraulic target value is delayed by a predetermined delay time ΔT from the rising timing of the front hydraulic target value, so as shown in FIG. It is possible to prevent the wheel cylinder pressures of 224RL and 224RR from exceeding the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR. As a result, the tendency to lock the rear wheel during four-wheel automatic braking when emergency deceleration is required can be prevented, and vehicle stability can be improved. From this point of view, the predetermined delay time ΔT is preferably a difference in characteristics between the rear wheel system hydraulic circuit 201R and the front wheel system hydraulic circuit 201F, in particular, the oil consumption necessary for generating the same wheel cylinder pressure. It is set in consideration of the amount difference. The predetermined delay time ΔT may be a fixed value such as 200 msec.

In the example shown in FIG. 6, the front hydraulic pressure target value and the rear hydraulic pressure target value rise steeply and rise toward the final front hydraulic pressure target value and the final rear hydraulic pressure target value, respectively. It may be increased in steps.

Next, a preferred example of the method for setting the predetermined delay time ΔT described above with reference to the example shown in FIG. 6 will be described with reference to FIGS.

FIG. 8 is a characteristic diagram showing an example of the relationship between wheel cylinder pressure and oil consumption. FIG. 8 shows the same relationship in the front wheel system hydraulic circuit 201F and the same relationship in the rear wheel system hydraulic circuit 201R. As shown in FIG. 8, the amount of oil consumed to generate the same wheel cylinder pressure differs between the front wheel system hydraulic circuit 201F and the rear wheel system hydraulic circuit 201R. This is mainly based on the structural difference (for example, the difference between the capacity of the front caliper and the capacity of the rear caliper). Such a characteristic diagram may be obtained based on a test or calculation, or a design value may be used.

FIG. 9 is a characteristic diagram showing an example of the discharge capacity (discharge oil amount with respect to time) of the pump 260F in the front wheel system hydraulic circuit 201F. Similarly, such a characteristic diagram may be obtained based on a test or calculation, or a design value may be used.

Here, it is assumed that the final hydraulic target value for the wheel cylinder pressure is Pt. In this case, consumption of the wheel system hydraulic circuit 201R after required for implementing the final and oil consumption Q _F in the front line hydraulic circuit 201F necessary for realizing the hydraulic target value Pt of the final hydraulic target value Pt and an oil amount Q _R, as shown in FIG. 8 is obtained from the characteristic diagram. These oil consumption difference Q _diff is Q _F −Q _R. At this time, the operation time T _t of the pump 260F required until oil consumption Q _F is obtained, as shown in FIG. 9 is obtained from the characteristic diagram. The predetermined delay time ΔT may be calculated by the following equation.
ΔT = T _t × (Q _diff / Q _F ) Formula (1)
When this calculation method is adopted, the control device 10 determines the predetermined delay time based on the final hydraulic target value Pt and the characteristic diagrams shown in FIGS. 8 and 9 in the process of step 502 shown in FIG. ΔT may be calculated. Alternatively, the relationship between the final hydraulic pressure target value Pt and the predetermined delay time ΔT may be created in advance as a map and stored in the memory. For example, a predetermined delay time ΔT may be calculated for each of a plurality of final hydraulic target values Pt (for example, 1 Mpa, 3 Mpa, 5 Mpa, and 7 Mpa) using Equation (1) to create a map. In this case, the control device 10 may read the predetermined delay time ΔT corresponding to the final hydraulic pressure target value Pt. For the final hydraulic pressure target value not specified in the map, the final hydraulic pressure target value not specified in the map is obtained by interpolating a predetermined delay time ΔT corresponding to the two final hydraulic pressure target values close thereto. A predetermined delay time ΔT corresponding to the above may be calculated.

As another method for calculating the predetermined delay time ΔT,
The predetermined delay time ΔT may be calculated by the following equation.
ΔT = T _t −T _tR equation (2)
_{Here, T tR} is consumed oil amount _{Q R} is the operating time of the pump 260R required until obtained. T _tR is a characteristic diagram as shown in FIG. 9 and may be similarly calculated based on a characteristic diagram of the discharge oil amount with respect to time of the pump 260R in the rear wheel system hydraulic circuit 201R. Similarly, in this case, a predetermined delay time ΔT may be calculated for each of a plurality of final hydraulic target values Pt (for example, 1 Mpa, 3 Mpa, 5 Mpa, and 7 Mpa) according to the equation (2), and a map may be created. .

FIG. 10 is a diagram showing another example of a time series (target control value pattern) of target control values set for each of the front wheel system and the rear wheel system. Here, as an example, the target control value is a hydraulic target value for the wheel cylinder pressure. In FIG. 10, as in FIG. 6, the time series of the hydraulic target value (front hydraulic target value) with respect to the wheel cylinder pressure of the front wheel cylinders 224FL and 224FR, and the hydraulic target with respect to the wheel cylinder pressure of the rear wheel wheel cylinders 224RL and 224RR. The time series of the values (rear hydraulic target values) are indicated by dotted lines, and the actual wheel cylinder pressures (front actual hydraulic pressure) of the front wheel cylinders 224FL and 224FR when controlled by these hydraulic target value patterns are shown. The time series and the time series of the actual wheel cylinder pressures (rear actual hydraulic pressure) of the wheel cylinders 224RL and 224RR of the rear wheels are indicated by solid lines.

In the example shown in FIG. 10, the rise timing of the rear hydraulic target value is the same as the rise timing of the front hydraulic target value, but the increase gradient of the rear hydraulic target value is set lower than the increase gradient of the front hydraulic target value. The Specifically, the front hydraulic pressure target value increases at a relatively steep slope toward the final front hydraulic pressure target value (5 Mpa in this example) at the start of the sudden braking command. On the other hand, the rear hydraulic pressure target value increases with a relatively gentle gradient toward the final front hydraulic pressure target value (5 Mpa in this example) at the start of the sudden braking command. In this manner, an upper limit value lower than the increase gradient of the front hydraulic pressure target value may be set for the increase gradient of the rear hydraulic pressure target value. The upper limit value (or the difference between the increase gradient of the rear hydraulic pressure target value and the increase gradient of the front hydraulic pressure target value) with respect to the increase gradient of the rear hydraulic pressure target value is determined by the wheel cylinder pressure of the rear wheel cylinders 224RL and 224RR. The wheel cylinder pressure is set so as not to exceed the wheel cylinder pressure of the wheel cylinders 224FL and 224FR.

Here, when the front hydraulic pressure target value and the rear hydraulic pressure target value increase at the same gradient with respect to time, as indicated by the solid lines attached to the front actual hydraulic pressure and the rear actual hydraulic pressure in FIGS. Due to the difference in oil consumption between the front wheel system hydraulic circuit 201F and the rear wheel system hydraulic circuit 201R as shown in FIG. 8, the rear actual hydraulic pressure increases with a steeper slope than the front actual hydraulic pressure. . In this regard, in the example shown in FIG. 10, as described above, the increase gradient of the rear hydraulic target value is smaller than the increase gradient of the front hydraulic target value, and thus the difference between the increase gradient of the rear actual hydraulic pressure and the increase gradient of the front actual hydraulic pressure. Can be reduced. This prevents the wheel cylinder pressures of the rear wheel cylinders 224RL and 224RR from exceeding the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR at the time of four-wheel automatic braking when emergency deceleration is required. It becomes possible to prevent the tendency to lock, and the vehicle stability can be improved.

Note that the method shown in FIG. 10 can be combined with the method shown in FIG. That is, it is possible to delay the rise timing of the rear hydraulic pressure target value from the rise timing of the front hydraulic pressure target value and set the increase gradient of the rear hydraulic pressure target value lower than the increase gradient of the front hydraulic pressure target value. Further, in the example shown in FIG. 10, the front hydraulic pressure target value rises steeply and rises toward the final front hydraulic pressure target value, but it may increase in two or more steps. The rear hydraulic pressure target value rises gently and rises toward the final rear hydraulic pressure target value, but may increase in two or more steps.

Next, another example of hydraulic control executed by the control device 10 when a predetermined emergency deceleration is requested will be described.

FIG. 11 is a flowchart showing another example of hydraulic control executed by the control device 10. The processing routine shown in FIG. 11 may be repeatedly executed at predetermined intervals while the vehicle is traveling. FIG. 12 is a diagram showing an example of each map 1, 2, 3 used in the processing shown in FIG.

In step 1100, the control device 10 determines a sudden braking command start condition. The sudden braking command start condition may be satisfied when a predetermined emergency deceleration is requested. In this example, the sudden braking command start condition is satisfied when there is a request from a pre-crash system that performs collision avoidance control with a forward obstacle. For example, in a pre-crash system, emergency deceleration is required when TTC falls below a predetermined value (for example, 1 second). The control device 10 may constitute a pre-crash system control device. In this example, the sudden braking command start condition is also satisfied when there is a request from a system other than the pre-crash system (a system that performs preceding vehicle tracking control, auto cruise control, or similar automatic driving control). . For example, in a system that performs automatic driving control such as preceding vehicle following control and auto cruise control, emergency deceleration is required when the target deceleration exceeds a predetermined value. The control device 10 may constitute a control device for a system that performs automatic driving control such as preceding vehicle following control and auto cruise control. If the sudden braking command start condition is satisfied, the process proceeds to step 1102; otherwise, the process ends.

In step 1102, the control device 10 determines whether or not the request is an emergency deceleration request from the pre-crash system. If it is a request for emergency deceleration from the pre-crash system, the process proceeds to step 1104. If it is a request for emergency deceleration from other systems, the process proceeds to step 1108.

In step 1104, the control device 10 executes a four-wheel automatic brake in which pressure increase by the rear wheel system hydraulic circuit 201R is suppressed based on the map 1 (see FIG. 12). Specifically, the control device 10 operates the

pumps

260F and 260R, and calculates the pressure increase gradient instruction amount in common for the front wheel system hydraulic circuit 201F and the rear wheel system hydraulic circuit 201R. That is, a common pressure increase gradient command amount is calculated for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F and the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R. The pressure increase gradient instruction amount may be calculated in a manner that gradually increases with time toward the final pressure increase gradient instruction amount. The final pressure increase gradient instruction amount may be a fixed value or a variable value set according to a relative relationship (such as TTC) with the front obstacle. Then, the control device 10 calculates a differential pressure command value corresponding to the calculated pressure increase gradient command amount based on the map 1, and calculates the differential pressure command value (current) as the M /

C cut valves

206F and 206R, respectively. Apply to. Here, in the map 1, the differential pressure command value with respect to the pressure increase gradient command amount is respectively determined for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F and the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R. Different. Specifically, for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F, when the pressure increase gradient command amount exceeds the first predetermined value ΔP _A1 , the differential pressure command value becomes the predetermined gradient G1 and the predetermined value S1 ( (The value close to the upper limit value or a value close to the upper limit value), while the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R has a pressure increase gradient instruction amount of the second predetermined value ΔP _A2. The differential pressure indication value does not increase until it exceeds (> ΔP _A1 ). Incidentally, with respect to the M / C cut valve 206R for the rear wheels system hydraulic circuit 201R, increasing the gradient indicated amount exceeds a second predetermined value [Delta] P _A2, in the same predetermined value S1 differential pressure instruction value is the same gradient G1 Increase towards. Therefore, when the common pressure increase gradient command amount is calculated over time for the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R and the M / C cut valve 206F of the front wheel system hydraulic circuit 201F, The manner in which the differential pressure command value for the M / C cut valve 206R increases is delayed in time from the mode in which the differential pressure command value for the M / C cut valve 206F increases. Thereby, the same effect as the case where the predetermined delay time ΔT as described with reference to FIG. 6 is set can be obtained. Note that the difference between the first predetermined value ΔP _A1 and the second predetermined value ΔP _A2 may be set in the same way as when the predetermined delay time ΔT is set.

In step 1106, the control device 10 determines the sudden braking command end condition. For example, when the collision is detected, the vehicle speed becomes 0 km / h, or when the TTC exceeds 1.5 [seconds], the sudden braking command is terminated for a predetermined time (for example, 3 seconds). ) It may be satisfied if it continues for the above. If the sudden braking command end condition is satisfied, the process ends as it is. Otherwise, the process returns to step 1104.

In step 1108, the control unit 10 calculates in common to the rear wheel system hydraulic circuit 201R and the front wheel system hydraulic circuit 201F the pressure increase gradient indicated amounts, or pressure-increase gradient instruction amount is larger than the predetermined value [Delta] P _A not Determine whether. If the pressure increase gradient instruction amount is larger than the predetermined value [Delta] P _A, the process proceeds to step 1110, if the pressure increase gradient instructed amount is smaller than the predetermined value [Delta] P _A, the process proceeds to step 1114. The determination increasing gradient indicated amounts of whether greater than a predetermined value [Delta] P _A may be performed only for the pressure increase gradient instruction amount calculated for the first time. In this case, after the next cycle, the process may proceed to step 1110 or 1114 according to the determination result for the pressure increase gradient instruction amount calculated for the first time.

In step 1110, the control device 10 executes a four-wheel automatic brake in which pressure increase by the rear wheel system hydraulic circuit 201R is suppressed based on the map 2 (see FIG. 12). Specifically, the control device 10 operates the

pumps

260F and 260R. Then, the control device 10 calculates a differential pressure command value corresponding to the calculated pressure increase gradient command amount based on the map 2, and uses the differential pressure command value (current) as the M /

C cut valves

206F and 206R, respectively. Apply to. Here, in the map 2, the differential pressure command value with respect to the pressure increase gradient command amount is respectively determined for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F and the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R. Different. Specifically, with respect to the M / C cut valve 206F of the front wheel system hydraulic circuit 201F, the pressure-increase gradient instruction amount exceeds a predetermined value [Delta] P _A, differential pressure instruction value toward a predetermined value S1 at a predetermined gradient G1 whereas increasing Te, for M / C cut valve 206R for the rear wheels system hydraulic circuit 201R, the pressure-increase gradient instruction amount exceeds a predetermined value [Delta] P _a, differential pressure instruction value is a predetermined gradient G2 (< G1) increases toward a predetermined value S2 (<S1). That is, when the pressure increase gradient command amount increases, the differential pressure command value for the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R is compared with the differential pressure command value for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F. Thus, it increases toward a small predetermined value S2 with a gentle slope. Therefore, when the common pressure increase gradient command amount is calculated over time for the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R and the M / C cut valve 206F of the front wheel system hydraulic circuit 201F, The increasing aspect of the differential pressure instruction value for the M / C cut valve 206R has a smaller increase gradient than the increasing aspect of the differential pressure instruction value for the M / C cut valve 206F. Thereby, the same effect as the case described with reference to FIG. 10 described above can be obtained.

Here, when an emergency deceleration request is issued from a system that performs automatic driving control such as preceding vehicle tracking control or auto cruise control, the pressure increase gradient command amount (target decrease) is lower than when emergency deceleration is requested from the pre-crash system. (Speed) tends to be small. That is, at the time of emergency deceleration by a system that performs automatic driving control such as preceding vehicle tracking control or auto cruise control, the wheel cylinder pressures of the rear wheel cylinders 224RL and 224RR are set in contrast to emergency deceleration by the pre-crash system. The need for increasing pressure to near the upper limit can be reduced. Considering this point, in Map 2, the predetermined value S2 of the differential pressure instruction value for the M / C cut valve 206R is smaller than the predetermined value S1 of the differential pressure instruction value for the M / C cut valve 206F. The vehicle wheel stability can be improved by preventing the wheel cylinder pressure on the side from being increased to the same level as the wheel cylinder pressure on the front wheel side.

In step 1112, the control device 10 determines a sudden braking command end condition. The sudden braking command end condition may be satisfied, for example, when a necessary inter-vehicle distance from the preceding vehicle is maintained, or when the sudden braking command continues for a predetermined time (for example, 3 seconds) or longer. If the sudden braking command end condition is satisfied, the process ends as it is. Otherwise, the process returns to step 1108.

In step 1114, the control device 10 executes the four-wheel automatic braking that does not suppress the pressure increase by the rear wheel system hydraulic circuit 201R based on the map 3 (see FIG. 12). Specifically, the control device 10 operates the

pumps

260F and 260R. The control device 10 calculates a differential pressure command value corresponding to the calculated pressure increase gradient command amount based on the map 2, and applies the differential pressure command value (current) to the M /

C cut valves

206F and 206R. To do. Here, in Map 3, the differential pressure command value for the pressure increase gradient command amount is the same for the M / C cut valve 206F of the front wheel system hydraulic circuit 201F and the M / C cut valve 206R of the rear wheel system hydraulic circuit 201R. . Specifically, for the front wheel system hydraulic circuit 201F of the M / C cut valve 206F and a rear wheel system hydraulic circuit 201R of M / C cut valve 206R, until the pressure-increase gradient indicated amount reaches a predetermined value [Delta] P _A, The differential pressure instruction value increases toward a predetermined value S3 (<S2) with a gentle predetermined gradient G3 (<G2).

In step 1116, the control device 10 determines the sudden braking command end condition. The sudden braking command end condition may be satisfied, for example, when the necessary inter-vehicle distance from the preceding vehicle is maintained, or when the sudden braking command continues for a predetermined time (for example, 2 seconds). If the sudden braking command end condition is satisfied, the process ends as it is. Otherwise, the process returns to step 1108.

As described above, according to the control method shown in FIG. 11, even when a sudden braking command for increasing the pressure increase gradient command amount is generated, the wheel cylinder pressures of the rear wheel cylinders 224RL and 224RR are changed to the front wheel wheel cylinders 224FL, It is possible to prevent the wheel cylinder pressure of 224FR from being exceeded, and to prevent a tendency to lock the rear wheel, thereby improving vehicle stability. Also, by using different maps (Fig. 12) for emergency deceleration from the pre-crash system and emergency deceleration from other systems, rapid braking according to the characteristics of each system can be achieved. It can be realized while maintaining.

Next, the case of the hydraulic circuit 200 'using X piping will be described.

FIG. 13 is a diagram illustrating an example of a hydraulic circuit 200 ′ using X piping. The hydraulic circuit 200 'shown in FIG. 13 includes two systems of

hydraulic circuits

201A and 201B. In the illustrated example, the two systems of

hydraulic circuits

201A and 201B are composed of X pipes that are divided into systems of a right front wheel 100FR and a left rear wheel 100RL, and a left front wheel 100FL and a right rear wheel 100RR. Hereinafter, the hydraulic circuit 201A related to the right front wheel 100FR and the left rear wheel 100RL is referred to as a first system hydraulic circuit 201A, and the hydraulic circuit 201B related to the left front wheel 100FL and the right rear wheel 100RR is referred to as a second system hydraulic circuit 201B. Called. In FIG. 13, a portion 220 surrounded by a two-dot chain line may be embodied as a brake actuator.

As shown in FIG. 13, the hydraulic circuit 200 ′ with X piping has a front wheel cylinders 224 FL and 224 FR and rear wheel cylinders 224 RL and 224 RR arranged with respect to the hydraulic circuit 200 with front and rear piping shown in FIG. Except for differences, they may be substantially the same. Therefore, in FIG. 13, the components that may be the same as those of the hydraulic circuit 200 with the front and rear pipes shown in FIG. “R” is changed to “A” and “B”, respectively, and the description is omitted.

Next, the hydraulic control executed by the control device 10 when a predetermined emergency deceleration is requested, that is, the hydraulic control in the hydraulic circuit 200 'using X piping will be described.

FIG. 14 is a flowchart illustrating an example of hydraulic control executed by the control device 10. The processing routine shown in FIG. 14 may be repeatedly executed at predetermined intervals while the vehicle is traveling.

Steps 1400 and 1404 may be the same as steps 500 and 504 in the flowchart described with reference to FIG.

In step 1402, the control unit 10 based on the target control value, the four-wheel automatic braking in a manner to keep the pressure difference between the systems in the first system hydraulic circuit 201A and the second system hydraulic circuit 201B within a predetermined value D _Th Execute. Specifically, the control device 10 operates the

pumps

260A and 260B and controls the M /

C cut valves

206A and 206B to increase the wheel cylinder pressures of the wheel cylinders 224FL, 224FR, 224RL and 224RR. At this time, the control device 10 determines the pressure difference between the wheel cylinder pressures of the wheel cylinders 224FL and 224RR related to the first system hydraulic circuit 201A and the wheel cylinder pressures of the wheel cylinders 224FL and 224RR related to the second system hydraulic circuit 201B. in a fit such embodiments within a predetermined value _{D Th,} controls the M / C cut

valve

206A, 206B.

Similarly, the target control value may be set for any physical quantity related to the wheel cylinder pressure of the wheel. For example, the target control value may be a target deceleration, a hydraulic pressure target value for the wheel cylinder pressure, a pressure increase gradient target value for the wheel cylinder pressure, or M / C. It may be a differential pressure target value (applied current value) for the

cut valves

206A and 206B. The target control value may be a fixed value or a variable value set according to a relative relationship (such as TTC) with the front obstacle.

The method for reducing the pressure difference between the systems in Step 1402 can be realized in a wide variety of modes, and may be realized in any mode. For example, based on the difference in the amount of oil consumed between the systems in the first system hydraulic circuit 201A and the second system hydraulic circuit 201B (difference caused by the difference in piping length, etc.), the system with the larger amount of oil consumption On the other hand, the target control value may be raised. For example, the consumed oil amount necessary to achieve the oil consumption Q _A required to achieve the final target control value in the first system hydraulic circuit 201A, the final target control value in the second system hydraulic circuit 201B Q _B is obtained based on the characteristic diagram as shown in FIG. 8, and a difference between these systems (difference in oil consumption Q _diff = | Q _A −Q _B |) is obtained, and the following index value N May be calculated.
N = Q _diff / Q _min
Here, Q _min is the smaller of the consumed oil amount Q _A and the consumed oil amount Q _B. The relationship between the index value N and the target control value raising amount ΔP may be created in advance as a map. When the target control value is a hydraulic pressure target value for the wheel cylinder pressure and the final target control value is a fixed value (for example, 5 Mpa), the target control value raising amount ΔP is also a fixed value (for example, , 0.2 Mpa) may be determined in advance. At this time, the constant value _DTh is set so that the pressure difference between the systems in the first system hydraulic circuit 201A and the second system hydraulic circuit 201B does not affect the vehicle behavior. For example, the constant value _DTh may be determined based on a minimum pressure difference that can affect the vehicle behavior. Such a minimum pressure difference depends on the performance of the vehicle (a wide variety of factors) and may be adapted by testing or the like.

As another method of reducing the pressure difference between the systems, the wheel speed of the right front wheel 100FR related to the first system hydraulic circuit 201A and the second system hydraulic circuit based on the output signals of the wheel speed sensors 138FR, 138FL, 138RR, 138RL. Based on the difference from the wheel speed of the left front wheel 100FL according to 201B, the target control value for the system with the smaller wheel speed decrease (sag) of the right front wheel 100FR and the left front wheel 100FL is set to the other system. It may be set higher (raised) than the target control value. Alternatively, based on the output signals of the wheel speed sensors 138FR, 138FL, 138RR, 138RL, the wheel speed of the left rear wheel 100RL related to the first system hydraulic circuit 201A and the wheel of the right rear wheel 100RR related to the second system hydraulic circuit 201B Based on the difference from the speed, the target control value for the system with the smaller wheel speed reduction (sag) of the left rear wheel 100RL and the right rear wheel 100RR is set to be higher than the target control value for the other system. It is good also as setting high (raising). Similarly, for example, when the target control value is a hydraulic target value for the wheel cylinder pressure and the final target control value is a fixed value (for example, 5 Mpa), the target control value raising amount ΔP is also fixed. A value (for example, 0.2 Mpa) may be determined in advance. Alternatively, the target control value raising amount ΔP may be varied in accordance with the magnitude of the difference in the reduction speed of the wheel speed. In this case, the relationship between the difference between the wheel speed reduction speeds and the raised amount ΔP may be created in advance as a map.

Note that the four-wheel automatic braking in step 1402 is typically executed under a situation where the driver does not operate the brake pedal 190. That is, the target control value used in step 1402 is a value (including a fixed value) determined based on factors other than the operation amount of the brake pedal 190. When the driver operates the brake pedal 190 after starting the four-wheel automatic braking, for example, the operation of the brake pedal 190 may be ignored and the four-wheel automatic braking may be continued. Alternatively, when the driver operates the brake pedal 190 after starting the four-wheel automatic braking, for example, when the master cylinder pressure becomes equal to or higher than a predetermined pressure, the normal braking may be performed. Alternatively, if the configuration of the hydraulic circuit 200 ′ shown in FIG. 13 is not possible, but other hydraulic circuit configurations are possible, the wheel cylinders 224FL, It is good also as applying to 224FR, 224RL, 224RR.

However, the four-wheel automatic braking in step 1402 may be executed under a situation where the driver is operating the brake pedal 190. In this case, the sudden braking command start condition may be varied depending on whether the driver operates the brake pedal 190 or not. For example, when there is an operation of the brake pedal 190 by the driver, the TTC as a threshold value that satisfies the sudden braking command start condition may be changed to a long time (for example, 1.5 seconds). In any case, when the four-wheel automatic brake is started, the operation of the brake pedal 190 may be ignored thereafter. That is, the target control value used in step 1402 may be determined based on factors other than the operation amount of the brake pedal 190. Alternatively, as described above, when the driver still operates the brake pedal 190 after starting the four-wheel automatic braking, for example, when the master cylinder pressure becomes a predetermined pressure or more, the process shifts to the normal brake. Alternatively, it is not possible with the configuration of the hydraulic circuit 200 ′ shown in FIG. 13, but when other hydraulic circuit configurations are possible, add both hydraulic pressures (or select the larger one). And may be applied to the wheel cylinders 224FL, 224FR, 224RL, 224RR.

Further, in the four-wheel automatic brake in step 1402, the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR are all maintained in the normal state. That is, the holding solenoid valves 212FL, 212FR, 212RL, and 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, and 214RR are individually controlled for each wheel in the vehicle stabilization control such as VSC. The four-wheel automatic brake is control for each system, and different control is not executed in the same system. However, vehicle stabilization control such as ABS or VSC may be activated after the start of the four-wheel automatic braking in step 1402. In this case, the four-wheel automatic brake may be stopped, or such other control may be executed while continuing the four-wheel automatic brake. In the latter case, the M /

C cut valves

206A and 206B are controlled in the same manner as in the four-wheel automatic braking, while the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR are used. It is good also as performing control according to the control law of ABS or vehicle stabilization control.

FIG. 15 is a diagram illustrating an example of a time series (target control value pattern) of target control values set for each of the first system hydraulic circuit 201A and the second system hydraulic circuit 201B. Here, as an example, the target control value is a hydraulic target value for the wheel cylinder pressure. In FIG. 15, a time series of hydraulic target values (first system hydraulic target values) with respect to the wheel cylinder pressures of the first system wheel cylinders 224RL and 224FR, and a hydraulic target with respect to the wheel cylinder pressures of the second system wheel cylinders 224FL and 224RR. The time series of the values (second system hydraulic target value) are indicated by dotted lines, and the actual wheel cylinder pressure (first system) of the wheel cylinder 224FR of the first system when controlled by these hydraulic target value patterns. The time series of the actual hydraulic pressure) and the time series of the actual wheel cylinder pressure (second system actual hydraulic pressure) of the wheel cylinder 224FL of the second system are indicated by solid lines.

In the example shown in FIG. 15, the final second system hydraulic pressure target value is set to a value higher than the original final hydraulic target value (= final first system hydraulic target value) by the raising amount ΔP. Specifically, the first system hydraulic pressure target value increases toward the final first system hydraulic pressure target value (5 Mpa in this example) at the start of the sudden braking command. On the other hand, the second system hydraulic pressure target value is the final second system hydraulic target value (5.2 Mpa in this example) that is raised by the raising amount ΔP from the final first system hydraulic target value at the start of the sudden braking command. Increase towards

FIG. 16 is a diagram illustrating a simultaneous sequence according to a comparative example in which the same (common) target control value is applied to the first system hydraulic circuit 201A and the second system hydraulic circuit 201B. In this comparative example, both the first system hydraulic target value and the second system hydraulic target value increase toward the final hydraulic target value (5 Mpa in this example) at the start of the sudden braking command. In such a configuration, due to the characteristic difference between the second system hydraulic circuit 201B and the first system hydraulic circuit 201A (difference in the amount of oil consumed due to the difference in piping length, design variation of various valves, etc.), FIG. The difference between the wheel cylinder pressure of the wheel cylinder 224FL of the second system and the wheel cylinder pressure of the wheel cylinder 224FR of the first system is constant, as shown by the solid lines attached to the first system actual hydraulic pressure and the second system actual hydraulic pressure. It becomes larger than the value _DTh .

On the other hand, in the example shown in FIG. 15, the final second system hydraulic pressure target value is set to a value higher than the original final hydraulic pressure target value by the raised amount ΔP. The wheel cylinder pressure of the first system wheel cylinder 224FR and the wheel cylinder pressure of the second system wheel cylinder 224FL can be increased in substantially the same manner. Thus, sudden vehicle deflection is prevented during four-wheel automatic braking when emergency deceleration is necessary, and vehicle stability can be improved.

Next, a preferred example of the method for setting the target control value raising amount ΔP described above with reference to the example shown in FIG. 14 will be described with reference to FIGS. 17 and 18. Here, as an example, it is assumed that the target control value is a hydraulic pressure target value with respect to the wheel cylinder pressure, and therefore the raising amount ΔP is a dimension of the hydraulic pressure. Further, here, the front wheel will be described, but the same may be applied to the rear wheel.

FIG. 17 is a diagram showing an example of the relationship between the vehicle speed and the wheel speed. FIG. 17 shows an example of a change mode of the vehicle body speed Vx during actual emergency deceleration, an example of a change mode of the wheel speed VwFL of the left front wheel 100FL, and an example of a change mode of the wheel speed VwFR of the right front wheel 100FR. Has been. The vehicle body speed Vx, the wheel speed VwFL of the left front wheel 100FL, and the wheel speed VwFR of the right front wheel 100FR shown in FIG. 17 may be calculated based on output signals of the wheel speed sensors 138FR, 138FL, 138RR, 138RL.

FIG. 18 is a diagram showing an example of the relationship between the slip ratio and the braking force. In FIG. 18, 0.08 is shown as an example of the slip ratio that exhibits the maximum braking force, and 8000 [N] is shown as an example of the maximum braking force. Such a characteristic diagram may be obtained based on a test or calculation, or a design value may be used.

Here, first, the slip ratio SFR of the right front wheel 100FR and the slip ratio SFL of the left front wheel 100FL are obtained from the following equations.
SFR = (Vx−VwFR) / Vx
SFL = (Vx−VwFL) / Vx
Next, based on the characteristic diagram as shown in FIG. 18, the braking rate BFR of the right front wheel 100FR and the braking force BFL of the left front wheel 100FL corresponding to the obtained slip rate SFR of the right front wheel 100FR, the slip rate SFL of the left front wheel 100FL, and For each. At this time, in a region smaller than the slip ratio that exhibits the maximum braking force (0.08 in this example), the braking force BFR and the braking force BFL are calculated by linear approximation as shown by the dotted line P in FIG. Also good. At this time, the difference between the calculated braking force BFR and the braking force BFL is the left-right braking force difference B _diff (= BFR−BFL). This braking force difference B _diff may be converted into a dimension of the hydraulic pressure P _diff . As the conversion method, for example, a relationship (characteristic) between a hydraulic pressure (for example, 7 Mpa) and a braking force necessary to realize a deceleration of 1 G (9.8 m / s ² ) may be used. In this case, the raising amount ΔP related to the left front wheel 100FL may be a hydraulic pressure P _diff obtained by converting the braking force difference B _diff .

When this calculation method is adopted, the control device 10 is based on the output signals of the wheel speed sensors 138FR, 138FL, 138RR, 138RL and the characteristic diagram shown in FIG. 18, for example, in the process of step 1402 shown in FIG. Then, the raising amount ΔP may be calculated. Alternatively, the relationship between the difference between the slip ratio SFR of the right front wheel 100FR and the slip ratio SFL of the left front wheel 100FL (or the braking force difference B _diff or the difference between the wheel speed VwFL and the wheel speed VwFR) and the raising amount ΔP is determined in advance. It may be created as a map and stored in memory. For example, the map may be created by calculating the raising amount ΔP for a plurality of slip ratio differences. In this case, the control device 10 may calculate the slip ratio difference based on the output signals of the wheel speed sensors 138FR, 138FL, 138RR, 138RL, and read the raised amount ΔP corresponding to the calculated slip ratio difference. For slip rate differences that are not defined in the map, an increase amount ΔP corresponding to a slip ratio difference that is not defined in the map is obtained by interpolating an increase amount ΔP corresponding to two slip ratio differences that are close to the difference. It may be calculated.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

For example, in the above-described embodiment, a configuration in which the wheel cylinder pressure sensor is not provided in the wheel cylinders 224FR, 224FL, 224RR, and 224RL is assumed. Even with such an inexpensive configuration, the vehicle stability during four-wheel automatic braking is improved by the feedforward control as described above, not by the feedback control based on the detection value of the wheel cylinder pressure sensor as described above. Is possible. However, the target control value may be fed back and set based on the output signals of the wheel speed sensors 138FR, 138FL, 138RR, and 138RL. In addition, this invention is applicable also to the structure provided with a wheel cylinder pressure sensor. In this case, the detected value of the wheel cylinder pressure sensor may be used as feedback control during four-wheel automatic braking, or the detected value of the wheel cylinder pressure sensor may not be used as feedback control during four-wheel automatic braking.

In the above-described embodiment, a configuration is assumed in which an accumulator that stores high-pressure oil discharged from the

pumps

260F and 260R (

pumps

260A and 260B) is not provided. In such a low-cost configuration, a large amount of high-pressure oil cannot be supplied from the accumulator in a short time, and thus a pressure difference between systems is particularly problematic. Therefore, the embodiment described above is particularly effective when the

pumps

260F and 260R (

pumps

260A and 260B) do not include an accumulator. However, the present invention is also applicable to a configuration provided with an accumulator.

In the above-described embodiment, the

pumps

260F and 260R (

pumps

260A and 260B) are provided for each system, but one common pump may be provided for the two systems. For example, in the hydraulic circuit 200, the

reservoirs

250F and 250R are integrated into one, the

pumps

260F and 260R are replaced with one common pump, and the discharge side of the common one pump is branched so that the

pump flow path

210F, 210R may be formed. The same applies to the hydraulic circuit 200 '. In this case, the “first hydraulic pressure generation source” and the “second hydraulic pressure generation source” in the claims are realized by the one common pump. In this case as well, one common pump may be provided with an accumulator.

The above-described embodiment relates to the hydraulic circuit 200 using the front and rear pipes and the hydraulic circuit 200 ′ using the X pipe, but the same idea as the hydraulic circuit 200 ′ using the X pipe is applied to the hydraulic circuit using the left and right pipes. be able to.

The illustrated hydraulic circuit 200 using the front and rear piping and the hydraulic circuit 200 ′ using the X piping are merely examples, and may be changed in various ways. For example, the hydraulic circuit 200 may be configured to turn on / off the flow of hydraulic pressure from the master cylinder 202 to the

pumps

260F, 260R by providing suction solenoid valves in the

flow paths

205F, 205R. In addition, two check valves may be provided on the suction sides of the

pumps

260F and 260R in the

pump channels

210F and 210R from the

reservoirs

250F and 250R, respectively, and the

channels

205F and 205R may be connected between the two check valves, respectively. . In this case, the

pumps

260F and 260R suck and discharge the oil from the master cylinder 202 without passing through the

reservoirs

250F and 250R. Further, the holding solenoid valves 212FL, 212FR, 212RL, 212RR and the pressure reducing solenoid valves 214FL, 214FR, 214RL, 214RR may be linear valves. Moreover, the structure which uses a common reservoir by the master cylinder 202 and the

pumps

260F and 260R may be sufficient. These changes can be similarly made in the hydraulic circuit 200 '.

In the above-described embodiment, the M /

C cut valves

206F and 206R are controlled in different modes during four-wheel automatic braking to control the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR and the rear wheel wheel cylinders 224RL and 224RR. Although the wheel cylinder pressure is increased, it is also possible to realize a similar pressure increasing mode by controlling the

pumps

260F and 260R in different modes during four-wheel automatic braking. In this case, the

pumps

260F and 260R may be driven by separate motors, and the M /

C cut valves

206F and 206R may be on / off valves. More specifically, at the time of four-wheel automatic braking, the M /

C cut valves

206F and 206R are closed, and the pump 260F and the pump 260R are controlled in different modes, that is, the rotational speed of the pump 260F (the discharge amount associated therewith). ) And the number of revolutions of pump 260R (and thus the discharge amount) are controlled in different modes, so that boosting of wheel cylinders 224FL, 224FR, 224RL, 224RR can be realized in the same manner as in the above-described embodiment. Good. These changes can be similarly made in the hydraulic circuit 200 '.

In the above-described embodiment, the M /

C cut valves

206F and 206R are controlled in different modes during four-wheel automatic braking to control the wheel cylinder pressures of the front wheel cylinders 224FL and 224FR and the rear wheel wheel cylinders 224RL and 224RR. Although the wheel cylinder pressure is increased, the holding solenoid valves 212FL and 212FR and the pressure reducing solenoid valves 214FL and 214FR related to the front wheel system hydraulic circuit 201F and the holding solenoid valve 212RL related to the rear wheel system hydraulic circuit 201R during four-wheel automatic braking. 212RR and pressure-reducing solenoid valves 214RL and 214RR can be controlled in different modes to achieve the same boosting mode. In this case, the M /

C cut valves

206F and 206R may be on / off valves. More specifically, during four-wheel automatic braking, the M /

C cut valves

206F and 206R are closed, the holding solenoid valves 212FL and 212FR and the pressure reducing solenoid valves 214FL and 214FR related to the front wheel system hydraulic circuit 201F, and the rear wheel system hydraulic pressure. By controlling the holding solenoid valves 212RL and 212RR and the pressure reducing solenoid valves 214RL and 214RR related to the circuit 201R in different modes, the boosting of the wheel cylinders 224FL, 224FR, 224RL and 224RR is realized in the same manner as in the above-described embodiment. It is good to do. However, in this case, the holding solenoid valves 212FL and 212FR related to the front wheel system hydraulic circuit 201F are controlled in the same manner, and the pressure reducing solenoid valves 214FL and 214FR related to the front wheel system hydraulic circuit 201F are controlled in the same manner. Similarly, holding solenoid valves 212RL and 212RR related to rear wheel system hydraulic circuit 201R are controlled in the same manner, and pressure reducing solenoid valves 214RL and 214RR related to rear wheel system hydraulic circuit 201R are controlled in the same manner. These changes can be similarly made in the hydraulic circuit 200 '.

Also, a circuit configuration typically used in a brake-by-wire system represented by ECB (Electric Control Braking System) may be employed. For example, a circuit configuration as disclosed in Japanese Patent Application Laid-Open No. 2006-103547 (however, the pressure reducing cut valve 90 can be omitted) may be employed. Also in this case, the “first hydraulic pressure generation source” and the “second hydraulic pressure generation source” in the claims are realized by the common one pump. In this case, the M / C cut valve may be an on / off valve. When such a circuit configuration is adopted, similarly, during the four-wheel automatic braking, the M / C cut valve is closed, and the holding solenoid valve and the pressure reducing solenoid valve are controlled in different modes for each system, thereby implementing the above-described implementation. The pressure increase of each wheel cylinder may be realized in the same manner as in the example. However, in this case as well, the holding solenoid valve and the pressure reducing solenoid valve are controlled in the same manner in each system.

In the above-described embodiment, the front radar sensor 134 is used for detecting a front obstacle, but a camera may be used instead of or in addition to the front radar sensor 134. For example, the front obstacle may be detected in cooperation with the front radar sensor 134 and the camera.

DESCRIPTION OF SYMBOLS 1 Vehicle braking device 10 Control apparatus 100FL Left front wheel 100FR Right front wheel 100RL Left rear wheel 100RR Right rear wheel 134 Front radar sensor 136 Acceleration sensor 138FL, FR, RL, RR Wheel speed sensor 190 Brake pedal 200, 200 'Hydraulic circuit 201A 1st 1 system hydraulic circuit 201B 2nd system hydraulic circuit 201F front wheel system hydraulic circuit 201R rear wheel system hydraulic circuit 202 master cylinder 204F, R master passage 205F, R flow path 206F, R, A, B M / C cut valve 208F, R high pressure Flow path 210F, R Pump flow path 212F, R Holding solenoid valve 214F, R Pressure reducing solenoid valve 216F, R Pressure reducing passage 224FL, FR, RL, RR Wheel cylinder 250F, R reservoir 260F, R, A, B Pump 262F, R Check valve 265 Master cylinder pressure sensor

Claims

A first system hydraulic circuit for supplying hydraulic pressure to a wheel cylinder of a first wheel of the vehicle;
A second hydraulic circuit for supplying hydraulic pressure to the wheel cylinder of the second wheel of the vehicle;
A first hydraulic pressure generating source that is provided in the hydraulic circuit of the first system and generates hydraulic pressure supplied to the wheel cylinder of the first wheel by the hydraulic circuit of the first system;
A first valve provided in the hydraulic circuit of the first system and configured to vary a wheel cylinder pressure of the first wheel;
A second hydraulic pressure generating source that is provided in the second hydraulic circuit and generates hydraulic pressure supplied to the wheel cylinder of the second wheel by the second hydraulic circuit;
A second valve provided in the hydraulic circuit of the second system and configured to vary a wheel cylinder pressure of the second wheel;
A third hydraulic pressure generating source that is connected to the hydraulic circuit of the first system and the hydraulic circuit of the second system, and generates hydraulic pressure according to the operation of the brake pedal of the driver;
A control device that executes emergency braking control independent of the driver's operation of the brake pedal when a predetermined emergency deceleration is requested,
In the emergency braking control, the control device controls the first valve and the second valve in different modes, or controls the first hydraulic pressure generation source and the second hydraulic pressure generation source in different modes. Then, based on the hydraulic pressure generated by the first hydraulic pressure generation source and the second hydraulic pressure generation source, the wheel cylinder pressure of the first wheel by the hydraulic circuit of the first system and the hydraulic circuit of the second system, and A vehicle braking device, wherein the wheel cylinder pressure of each of the second wheels is increased.
In the emergency braking control, the control device determines a target value related to the wheel cylinder pressure of the first wheel and a target value related to the wheel cylinder pressure of the second wheel based on factors other than the operation amount of the brake pedal of the driver. The vehicle braking device according to claim 1, wherein the braking device is set.
The vehicle control device according to claim 2, wherein the control device sets the target value based on a difference between an oil consumption amount in the hydraulic circuit of the first system and an oil consumption amount in the hydraulic circuit of the second system. Braking device.
The hydraulic circuit of the first system and the second system is configured by front and rear piping, the first wheel is a front wheel, and the second wheel is a rear wheel. The vehicle brake device described in 1.
5. The vehicle braking device according to claim 4, wherein the control device delays the pressure increase start timing of the wheel cylinder pressure of the rear wheel from the pressure increase start timing of the wheel cylinder pressure of the front wheel in the emergency braking control.
In the emergency braking control, the control device is configured so that the wheel cylinder pressure of the rear wheel does not become higher than the wheel cylinder pressure of the front wheel, and the first valve and the second valve or the first hydraulic pressure generation source. The vehicle braking device according to claim 4, wherein the second hydraulic pressure generating source is controlled.
5. The control device according to claim 4, wherein in the emergency braking control, an upper limit value that is lower than a pressure increase gradient of a wheel cylinder pressure of a front wheel is applied to a pressure increase gradient of a wheel cylinder pressure of a front wheel. Brake device for vehicles.
2. The hydraulic circuit of the first system and the second system is configured by X piping, the first wheel is a front left wheel and a rear right wheel, and the second wheel is a front right wheel and a rear left wheel. 4. The vehicle braking device according to any one of 1 to 3.
In the emergency braking control, the control device determines a wheel speed of the first wheel and the second wheel based on a difference between a wheel speed of the first wheel and a wheel speed of the second wheel. The vehicle braking device according to claim 8, wherein the target value related to the wheel cylinder pressure of the wheel with the smaller decrease is set higher than the target value related to the wheel cylinder pressure of the other wheel.
10. The vehicle braking device according to claim 1, wherein each of the first hydraulic pressure generation source and the second hydraulic pressure generation source includes a pump that does not include an accumulator.
The vehicle brake device according to any one of claims 1 to 10, wherein a wheel cylinder pressure sensor is not provided in the wheel cylinder of the first wheel and the wheel cylinder of the second wheel.
The first valve and the second valve each include a master cylinder cut valve, a holding solenoid valve, and a pressure reducing solenoid valve,
In the emergency braking control, the control device includes a master cylinder cut valve or a holding solenoid valve and a pressure reducing solenoid valve according to the first valve, and a master cylinder cut valve or a holding solenoid valve according to the second valve. The vehicle braking device according to any one of claims 1 to 11, wherein the pressure-reducing solenoid valve is controlled in a different manner.
Each of the first hydraulic pressure generation source and the second hydraulic pressure generation source includes a pump having a variable rotation speed,
The said control apparatus controls the rotation speed of the pump which concerns on a said 1st oil pressure generation source, and the rotation speed of the pump which concerns on a said 2nd oil pressure generation source in the said emergency braking control in a mutually different aspect. 12. The vehicle braking device according to any one of .about.11.
The first wheel includes two wheels,
The second wheel includes two wheels;
The control device performs, in the emergency braking control, the same mode of control for each wheel of the first wheel and the same mode of control for each wheel of the second wheel. The vehicle braking device according to any one of 13.
In the emergency braking control, the control device controls two sets of holding solenoid valves and pressure reducing solenoid valves related to each wheel of the first wheel in the same manner, and two sets of related wheels related to each wheel of the second wheel. The vehicle braking device according to claim 14, wherein the holding solenoid valve and the pressure reducing solenoid valve are controlled in the same manner.