JP2011093352A - Brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device which prevents inrush currents from overlapping when pumps for supplying brake fluid to wheel cylinders are started while reducing differences in braking forces applied to wheels. <P>SOLUTION: The brake control device 100 includes a plurality of pumps, which supply the brake fluid to wheel cylinders 6 according to driving via a pressure pump provided in fluid pressure circuits, and a control means, which controls the supply of the brake fluid to wheel cylinders 6 by driving the pumps and compares the responsiveness of supplying the brake fluid by a plurality of the pumps. The control means makes the timing of starting to drive motors different based on the responsiveness of the supply of the brake fluid by the pumps. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake control device that applies braking force to wheels.

  2. Description of the Related Art Conventionally, there is known a hydraulic brake device that controls the hydraulic pressure supplied to each wheel cylinder by electronically controlling the supply of brake fluid to a wheel cylinder via a hydraulic circuit by an actuator (for example, Patent Document 1). reference).

  In the brake control device described in Patent Document 1, if the accelerator pedal and the brake pedal are released and the vehicle is not turning, an early current is supplied to the motor of the electric drum brake. By supplying an early current to the motor of the electric drum brake prior to the depression of the pedal, the current supply is started earlier than the electric disc brake, and the current supply start timing is made different between the disc brake and the drum brake.

JP 2001-106055 A

  In Patent Document 1, the current supply start timing is varied depending on the types of brakes of the disc brake and the drum brake, and there remains a problem that the current supply start timing overlaps in the same type of brake.

  In a system in which brake fluid is supplied to each wheel cylinder using a plurality of motors as drive sources, inrush currents of the plurality of motors may overlap when brake fluid is supplied to each wheel cylinder simultaneously. In addition, when the timings of starting the plurality of motors are varied, there is a possibility that a difference occurs in the braking force applied to the wheels.

  The present invention has been made in view of such a situation, and an object of the present invention is to start a motor that drives a pump that supplies brake fluid to a wheel cylinder while reducing a difference in braking force applied to the wheel. It is an object of the present invention to provide a brake control device that prevents overlapping inrush currents.

  In order to solve the above problems, an aspect of the present invention provides a brake control device that applies braking force to a wheel by supplying brake fluid to a wheel cylinder via a hydraulic circuit, and is provided in the hydraulic circuit. A plurality of pumps for supplying brake fluid to the wheel cylinders according to driving through the hydraulic pressure source, and controlling the supply of brake fluid to the wheel cylinders by driving the pumps, and braking by the plurality of pumps And a control means for comparing the responsiveness of the liquid supply. This control means varies the timing of starting the drive of the pump based on the comparison result of the response of the brake fluid supply by the plurality of pumps.

  According to this aspect, it is possible to prevent the inrush currents of the motors that drive the pumps from overlapping as compared with the case where a plurality of pumps are driven simultaneously. Also, the pump drive timing is determined based on the responsiveness of the brake fluid supply by the pump, and the pump drive start timing is made different, so that the pump drive timing is made different. The difference in braking force can be reduced.

  The control means may drive the pump determined to be slow in response among the plurality of pumps in advance of the other pumps. As a result, by driving the pump with slow response in advance, the wheel cylinder pressure corresponding to the pump with fast response can quickly catch up with the wheel cylinder pressure corresponding to the pump with slow response. It is possible to reduce the difference in braking force applied to the wheels caused by changing the drive timing.

  The control means delays the start of driving of the pump that is determined to be fast in response among the plurality of pumps. By delaying the start of the drive of the pump with fast response, the wheel cylinder pressure corresponding to the pump with fast response can quickly catch up with the wheel cylinder pressure corresponding to the pump with slow response. The difference in braking force applied to the wheels caused by the difference can be reduced.

  The brake fluid may be supplied to each of the wheel cylinders corresponding to the wheels on the left and right of the vehicle by driving each of the plurality of motors that drive the pump. The wheels on the left and right of the vehicle refer to the left front wheel and the right front wheel, for example. The control means holds the responsiveness of the supply of brake fluid by a plurality of pumps, and the comparison may be performed by correcting the responsiveness based on the knockback correction value corresponding to the turning of the vehicle. Thereby, the response can be compared based on the more accurate response of the brake fluid supply according to the driving situation.

  The control means may detect the response of the brake fluid supply by the plurality of pumps held by driving the plurality of pumps simultaneously. By detecting the response of the brake fluid supplied by the pump under the same conditions, the difference in response can be accurately detected.

  Based on the difference between the wheel cylinder target hydraulic pressure and the wheel cylinder pressure, the control means relieves the target hydraulic pressure corresponding to the pump driven with a delay, and the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure. You may correct | amend as follows. Thereby, the differential pressure generated in the left and right wheel cylinder pressures can be reduced so as not to impair the vehicle braking response. The left and right wheel cylinder pressures refer to, for example, a wheel cylinder pressure corresponding to the left front wheel and a wheel cylinder pressure corresponding to the right front wheel.

  When the output of the pump driven late is maximum, the control means reduces the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure. You may correct to. If the output of the motor driven with a delay is maximum, the output of the motor driven with a delay cannot be increased any more. Therefore, when the output of the pump driven with a delay cannot be adjusted, the target hydraulic pressure corresponding to the pump driven in advance can be corrected to reduce the differential pressure generated in the left and right wheel cylinder pressures.

  When the difference between the target hydraulic pressure of the wheel cylinder corresponding to the pump driven late and the wheel cylinder pressure is within a predetermined range, the control means determines the target hydraulic pressure corresponding to the pump driven in advance You may correct | amend so that the differential pressure | pressure of the wheel cylinder pressure of this and target hydraulic pressure may be eased. As a result, when the wheel cylinder pressure corresponding to the pump driven late is appropriate, the target hydraulic pressure corresponding to the pump driven in advance is corrected, and the differential pressure generated in the left and right wheel cylinder pressures is reduced. can do.

  The brake fluid may be supplied to the wheel cylinders corresponding to the two wheels on the diagonal of the vehicle by driving one motor that drives the pump. The two wheels on the diagonal of the vehicle refer to, for example, a left front wheel and a right rear wheel, and a right front wheel and a left rear wheel. Thereby, even if it is a case where one system | strain is not used, braking force can be provided to a right-and-left wheel.

  When shifting the start timing of driving of a plurality of pumps, the control means controls a difference in braking force generated between two diagonal wheels to which brake fluid is supplied by a motor corresponding to a pump driven in advance. The target hydraulic pressure of the wheel cylinder may be corrected so as to be smaller than the power difference. As a result, it is possible to reduce a difference in braking force generated between the left and right wheels that is generated while shifting the timing of starting the driving of the pump.

  According to the present invention, in the brake control device, it is possible to prevent the inrush current from overlapping when the motor that drives the pump that supplies the brake fluid to the wheel cylinder is activated while reducing the difference in braking force applied to the wheel. .

It is a schematic structure figure of a brake control device concerning an embodiment. It is a figure showing functional composition of brake ECU concerning an embodiment. It is a figure which shows the function structure of the hydraulic-pressure control part which concerns on embodiment. It is a figure which shows the map of the control characteristic which concerns on embodiment. It is a flowchart which shows the brake control process which concerns on embodiment. It is a flowchart which shows the delay control which concerns on embodiment. It is a flowchart which shows the responsiveness detection process of the pump which concerns on embodiment. It is a flowchart which shows the correction process of the responsiveness of the pump which concerns on embodiment. It is a figure which shows the function for calculating the knockback correction value which concerns on embodiment. It is a figure which shows the function for calculating the knockback correction value which concerns on embodiment. It is a flowchart which shows the right-and-left differential pressure correction process which concerns on embodiment. It is a figure which shows the predetermined 2nd threshold value which concerns on embodiment. (A)-(c) is a schematic diagram explaining the braking force concerning each wheel. It is a flowchart which shows the distribution correction process which concerns on embodiment. It is a figure which shows distribution of the braking force in the distribution correction process which concerns on embodiment. (A) And (b) is a figure which shows the conventional brake control result. (A) And (b) is a figure which shows the brake control result which gave the delay to the 2nd motor which concerns on embodiment. (A) And (b) is a figure which shows the brake control result which gave the delay to the 1st motor which concerns on embodiment. (A) And (b) is a figure which shows the brake control result which gave the delay to the 1st motor which concerns on embodiment, and performed the right-and-left differential pressure correction process.

  FIG. 1 is a schematic configuration diagram of a brake control device 100 according to the embodiment. In this figure, an example in which the brake control device 100 according to the embodiment is applied to a vehicle constituting a hydraulic circuit of X piping provided with piping systems of right front wheel-left rear wheel and left front wheel-right rear wheel will be described. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  As shown in FIG. 1, the brake control apparatus 100 includes a brake pedal 1, a stroke sensor 2, a master cylinder 3, a stroke control valve 30, a stroke simulator 4, a brake fluid pressure control actuator 5, a wheel cylinder 6FL, 6FR, 6RL, 6RR (hereinafter collectively referred to as "wheel cylinder 6"). In addition, the brake control device 100 includes a brake ECU 200 as a control unit that controls the operation of each unit of the brake control device 100. The brake control device 100 supplies hydraulic pressure (referred to as “wheel cylinder pressure”) to the wheel cylinder 6 by supplying brake fluid to the wheel cylinder 6 via a hydraulic circuit, and applies braking force to the wheel by the hydraulic pressure. To do. Each wheel cylinder 6 may be built in a brake disc (not shown) and a brake caliper (not shown), and includes a wheel cylinder, a brake disc, and a brake caliper, and is called a disc brake unit.

  When the brake pedal 1 is depressed by the driver, a pedal stroke as an operation amount of the brake pedal 1 is input to the stroke sensor 2, and a detection signal corresponding to the pedal stroke is output from the stroke sensor 2. This detection signal is input to the brake ECU 200, and the brake ECU 200 detects the pedal stroke of the brake pedal 1. Here, the stroke sensor 2 is taken as an example of the operation amount sensor for detecting the operation amount of the brake operation member, but a pedal force sensor for detecting the pedal force applied to the brake pedal 1 may be used. An acceleration sensor 50 is connected to the brake ECU 200.

  The brake pedal 1 is connected to a push rod that transmits the pedal stroke to the master cylinder 3, and when the push rod is pushed, the master chamber 3a and the secondary chamber 3b provided in the master cylinder 3 are mastered. Cylinder pressure is generated.

  The master cylinder 3 is provided with a primary piston 3c and a secondary piston 3d that constitute a primary chamber 3a and a secondary chamber 3b. The primary piston 3c and the secondary piston 3d are configured to receive the elastic force of the spring 3e so that when the brake pedal 1 is not depressed, the pistons 3c and 3d are pressed to return the brake pedal 1 to the initial position side. ing.

  The primary chamber 3a and the secondary chamber 3b of the master cylinder 3 are connected to a pipeline B and a pipeline A that extend toward the brake fluid pressure control actuator 5, respectively.

  The master cylinder 3 is provided with a reservoir tank 3f. The reservoir tank 3f is connected to each of the primary chamber 3a and the secondary chamber 3b via a passage (not shown) when the brake pedal 1 is in the initial position, and supplies the brake fluid into the master cylinder 3 or the master tank 3f. Excess brake fluid in the cylinder 3 is stored. A pipeline C and a pipeline D extending toward the brake fluid pressure control actuator 5 are connected to the reservoir tank 3f.

  The stroke simulator 4 is connected to a pipeline E connected to the pipeline A, and plays a role of accommodating brake fluid in the secondary chamber 3b. The pipe E is provided with a stroke control valve 30 constituted by a normally-closed two-position valve capable of controlling the communication / blocking state of the pipe E. The stroke control valve 30 allows the brake fluid to be supplied to the stroke simulator 4. It is configured so that the flow can be controlled.

  The brake fluid pressure control actuator 5 is provided with a pipe line F connected to the pipe line A so as to connect the secondary chamber 3b of the master cylinder 3 and the wheel cylinder 6FR corresponding to the front wheel FR. The pipe F is provided with a shutoff valve 36. The shutoff valve 36 is a two-position valve that is open (communication state) when not energized, and is closed (shutoff state) when energized. The shutoff valve 36 controls the communication / shutoff state of the pipe F. Brake fluid supply to the wheel cylinder 6FR via the paths A and F is controlled.

  Further, the brake fluid pressure control actuator 5 is provided with a pipeline G connected to the pipeline B so as to connect the primary chamber 3a of the master cylinder 3 and the wheel cylinder 6FL corresponding to the front wheel FL. The pipe line G is provided with a shut-off valve 37. The shut-off valve 37 is a two-position valve that is opened when not energized and closed when energized. The shut-off valve 37 controls the communication / shut-off state of the pipeline G, whereby the wheel via the pipelines B and G is controlled. Brake fluid supply to the cylinder 6FL is controlled.

  Further, the brake fluid pressure control actuator 5 is provided with a pipeline H connected to the pipeline C extending from the reservoir tank 3f and a pipeline I connected to the pipeline D. The pipe H is branched into two pipes H1 and H2, and is connected to the wheel cylinders 6FR and 6RL, respectively. Further, the pipeline I branches into two pipelines I3 and I4 and is connected to the wheel cylinders 6FL and 6RR, respectively. The wheel cylinder 6RL and the wheel cylinder 6RR correspond to the rear wheel RL and the rear wheel RR, respectively.

  Each of the pipelines H1, H2, I3, and I4 is provided with one pump 7, 8, 9, and 10, respectively. Each pump 7-10 is comprised, for example by the trochoid pump excellent in silence. Of the pumps 7 to 10, the two pumps 7 and the pump 8 are driven by the first motor 11, and the two pumps 9 and the pump 10 are driven by the second motor 12. The 1st motor 11 and the 2nd motor 12 supply brake fluid to each wheel cylinder 6 according to a drive via each pump 7-10. In the embodiment, the four pumps 7 to 10 function as hydraulic pressure sources. Each pump 7-10 is provided in a hydraulic circuit, and supplies a brake fluid to a wheel cylinder according to the rotation speed of the 1st motor 11 or the 2nd motor 12 which was connected. That is, two pumps are operated by driving one motor, and one wheel cylinder is connected to each of the two pumps. The batteries that supply power to the first motor 11 and the second motor 12 may be common.

  Each of the pumps 7 to 10 is provided with pipelines J1, J2, J3, and J4 in parallel. A pipe J1 connected in parallel to the pump 7 is provided with a communication valve 38 and a hydraulic pressure adjusting valve 32 connected in series. The communication valve 38 and the hydraulic pressure adjustment valve 32 are arranged such that the communication valve 38 is on the suction port side of the pump 7 (downstream side in the brake fluid flow direction in the pipe J1), and the hydraulic pressure adjustment valve 32 is on the discharge port side (pipe). It arrange | positions so that it may each be located in the upstream of the brake fluid flow direction in the path | route J1. That is, the communication valve 38 can control the communication / blocking between the reservoir tank 3f and the hydraulic pressure adjustment valve 32. The communication valve 38 is a two-position valve that is closed when not energized and opened when energized, and the hydraulic pressure adjusting valve 32 is open when de-energized and closed when energized. It is a normally open linear valve that is adjusted.

  Here, the following force acts on the hydraulic pressure adjusting valve 32. The electromagnetic driving force according to the energization current to the linear solenoid of the hydraulic pressure adjusting valve 32 is F1, the spring biasing force is F2, and the differential pressure acting force according to the differential pressure between the inlet and outlet of the hydraulic pressure adjusting valve 32 is F3. Assuming that the frictional force F4 with respect to the sliding of the solenoid is satisfied, the relationship of F1 = F2 + F3 + F4 is established, and the opening of the hydraulic pressure adjusting valve 32 depends on the value of {(F2 + F3 + F4) −F1}. That is, as the electromagnetic driving force F1 increases, the valve opening decreases.

  Next, the hydraulic pressure adjusting valve 32 has the following valve closing current characteristics. The valve closing current refers to the value of the energization current to the valve when the valve is closed from the opened state. The valve closing current characteristic refers to a characteristic indicating the relationship between the valve closing current and the wheel cylinder pressure. The valve closing current characteristic is a linear function in which the valve closing current is linearly proportional to the wheel cylinder pressure. The hydraulic fluid of the hydraulic pressure adjustment valve 32 is discharged from the wheel cylinder 6FR toward the communication valve 38 on the downstream side. In a normally open type linear valve, the opening degree of the valve decreases as the energizing current of the hydraulic pressure adjusting valve 32 increases, and the flow rate of the hydraulic pressure adjusting valve 32 decreases. When the energization current reaches the valve closing current, the hydraulic pressure adjustment valve 32 is closed, and the flow rate of the hydraulic pressure adjustment valve 32 becomes zero. The flow rate of the hydraulic pressure adjustment valve 32 refers to the flow rate of brake fluid that passes through the hydraulic pressure adjustment valve 32.

  A hydraulic pressure adjustment valve 33 is provided in the pipe line J2 connected in parallel to the pump 8. The hydraulic pressure adjustment valve 33 is a linear valve, like the hydraulic pressure adjustment valve 32. The hydraulic pressure adjustment valves 33 to 35 that are normally open linear valves also function in the same manner as the hydraulic pressure adjustment valve 32. Hereinafter, the hydraulic pressure adjusting valves 32 to 35 may be collectively referred to simply as “hydraulic pressure adjusting valves”.

  A pipe J3 connected in parallel to the pump 9 is provided with a communication valve 39 and a hydraulic pressure adjusting valve 35 connected in series. As for the communication valve 39 and the hydraulic pressure adjusting valve 35, the communicating valve 39 is on the suction port side of the pump 9 (downstream side in the direction of the brake fluid flow in the pipe line J3), and the hydraulic pressure adjusting valve 35 is on the discharge port side of the pump 9 (pipe). It arrange | positions so that it may each be located in the brake fluid flow direction in the path | route J3. That is, the communication valve 39 can control the communication / blockage between the reservoir tank 3 f and the hydraulic pressure adjustment valve 35. The communication valve 39 is a two-position valve that is closed when not energized and opened when energized, and the hydraulic pressure adjusting valve 35 is open when de-energized and closed when energized. A linear valve to be adjusted. The opening of the hydraulic pressure adjusting valve 35 is adjusted by energization control to adjust the amount of brake fluid in the wheel cylinder 6FL.

  A hydraulic pressure adjusting valve 34 is provided in the pipe line J4 connected in parallel to the pump 10. The hydraulic pressure adjustment valve 34 is a linear valve, like the hydraulic pressure adjustment valve 35.

  And hydraulic pressure sensors 13, 14, 15, and 16 are arranged between each pump 7-10 in each of pipelines J1-J4 and each wheel cylinder 6FR, 6FL, 6RR, 6RL, and each wheel cylinder 6FR. , 6FL, 6RR, 6RL can be detected. Further, fluid pressure sensors 17 and 18 are also arranged upstream of the shutoff valves 36 and 37 (on the master cylinder 3 side) in the pipelines F and G, and are generated in the primary chamber 3a and the secondary chamber 3b of the master cylinder 3. The master cylinder pressure can be detected.

  Furthermore, check valves 20 and 21 are provided in the discharge port of the pump 7 for pressurizing the wheel cylinder 6FR and the discharge port of the pump 9 for pressurizing the wheel cylinder 6FL, respectively. The check valves 20 and 21 are provided to prohibit the flow of brake fluid from the wheel cylinders 6FR and 6FL to the pumps 7 and 9, respectively. With such a structure, the brake fluid pressure control actuator 5 is configured.

  In the brake control device 100 having the above-described configuration, a circuit that connects the reservoir tank 3f and the wheel cylinders 6FR and 6RL through the pipe C, the pipe H, the pipe H1, and the pipe H2 and the pumps 7 and 8 are connected in parallel. The hydraulic circuit including the connected pipelines J1 and J2 and the hydraulic circuit connecting the secondary chamber 3b and the wheel cylinder 6FR through the pipeline A and the pipeline F constitute the first piping system. .

  A circuit connecting the reservoir tank 3f and the wheel cylinders 6FL and 6RR through the pipe D, the pipe I, the pipe I3, and the pipe I4, and circuits of the pipes J3 and J4 connected in parallel to the pumps 9 and 10 And a hydraulic circuit that connects the primary chamber 3a and the wheel cylinder 6FL through the pipeline B and the pipeline G constitutes a second piping system.

  Then, the detection signals of the stroke sensor 2 and the hydraulic pressure sensors 13 to 18 are input to the brake ECU 200, and the stroke control valve 30 is based on the pedal stroke, the hydraulic pressure of the wheel cylinder, and the master cylinder pressure obtained from these detection signals. , Shut-off valves 36 and 37, communication valves 38 and 39, and hydraulic pressure adjusting valves 32 to 35 (hereinafter collectively referred to as “each hydraulic pressure adjusting valve”), the first motor 11 and the second motor 12 are driven. A control signal for this is output from the brake ECU 200.

  In normal times, when the brake pedal 1 is depressed and the detection signals of the stroke sensor 2 and the hydraulic pressure sensors 17 and 18 are input to the brake ECU 200, the brake ECU 200 sets the electromagnetic control valves 30, 32 to 39 and the first motor 11 to each other. Then, the second motor 12 is controlled to be in the following state. That is, energization of both the shutoff valve 36 and the shutoff valve 37 is turned on, and energization of the communication valve 38 and the communication valve 39 is both turned on. Thus, the shutoff valve 36 and the shutoff valve 37 are shut off, and the communication valve 38 and the communication valve 39 are put in a communication state.

  Moreover, the opening degree of the hydraulic pressure adjusting valves 32 to 35 is adjusted according to the energization current value. The stroke control valve 30 is energized. For this reason, even if each piston 3c, 3d moves, when the stroke simulator 4 will be in communication with the secondary chamber 3b through the pipe lines A and E and the brake pedal 1 is depressed, the brake fluid in the secondary chamber 3b Will move to the stroke simulator 4. Therefore, when the master cylinder pressure becomes high, the brake pedal 1 can be stepped on without causing a feeling of stepping on a hard plate against the brake pedal 1.

  Furthermore, energization of the first motor 11 and the second motor 12 is both turned on, and the brake fluid is discharged from the pumps 7 to 10 to the wheel cylinder 6 without passing through the electromagnetic control valve. That is, when the pump operation by the pumps 7 to 10 is performed, the brake fluid is supplied to each wheel cylinder 6.

  The brake ECU 200 controls the motor rotation speeds of the first motor 11 and the second motor 12, whereby the amount of brake fluid supplied to the wheel cylinder 6 is controlled. At this time, since the shut-off valve 36 and the shut-off valve 37 are in the shut-off state, the hydraulic pressure downstream of the pumps 7 to 10, that is, the amount of brake fluid supplied to each wheel cylinder 6 increases. Since the communication valve 38 and the communication valve 39 are in a communication state and the opening degrees of the hydraulic pressure adjustment valves 32 to 35 are controlled, the brake fluid is discharged according to the opening degrees, and each wheel cylinder 6 The hydraulic pressure is adjusted.

  The brake ECU 200 monitors the hydraulic pressure supplied to each wheel cylinder 6 based on the detection signals of the respective hydraulic pressure sensors 13 to 16 and controls the energization current value to the hydraulic pressure adjusting valves 32 to 35. The hydraulic pressure of each wheel cylinder 6 is set to a desired value. Thereby, the braking force according to the pedal stroke of the brake pedal 1 is generated. As described above, the brake control of the brake control device 100 of the embodiment is performed.

  FIG. 2 shows a functional configuration of the brake ECU 200 according to the embodiment. The brake ECU 200 includes a target hydraulic pressure calculation unit 42, a left / right differential pressure correction unit 43, a hydraulic pressure control unit 44, a responsiveness calculation unit 46, a delay control unit 48, a motor drive unit 52, and a hydraulic pressure adjustment valve. And a drive unit 54.

  The target hydraulic pressure calculation unit 42 calculates a target hydraulic pressure corresponding to the braking force to be applied to each wheel cylinder 6 based on the outputs of the stroke sensor 2 and the hydraulic pressure sensors 17 and 18. The target hydraulic pressure calculation unit 42 may calculate the target hydraulic pressure according to the output from a given driving support control unit.

  The left-right differential pressure correction unit 43 corrects the target hydraulic pressure so as to relieve the differential pressure between the left and right wheel cylinder pressures generated by the delay control and the target hydraulic pressure of the wheel cylinders. For example, if the output of the motor driven with a delay is not the maximum or the delay control is not being performed, the left / right differential pressure correction unit 43 determines the target hydraulic pressure corresponding to the motor driven with a delay as Correction is performed so as to reduce the differential pressure from the target hydraulic pressure of the wheel cylinder. In order to reduce the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure of the wheel cylinders while minimizing the vehicle braking response as much as possible, the left / right differential pressure correction unit 43 outputs the output of the motor driven with a delay. In the case where adjustment is possible, the hydraulic pressure of the wheel cylinder corresponding to the motor driven late is corrected to catch up with the wheel cylinder pressure corresponding to the motor driven in advance. Reducing the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure of the wheel cylinder is to reduce the differential pressure between the wheel cylinder pressure of the first motor 11 system and the wheel cylinder pressure of the second motor 12 system. That may be.

  The hydraulic pressure control unit 44 receives the target hydraulic pressure from the left / right differential pressure correction unit 43. The hydraulic pressure control unit 44 controls the wheel cylinder pressure according to the target hydraulic pressure. Specifically, the hydraulic pressure control unit 44 calculates the motor rotation speeds of the first motor 11 and the second motor 12 by a predetermined calculation formula based on the target hydraulic pressure. Here, for example, the motor rotation speed of the first motor 11 is calculated based on a higher target flow rate among the target flow rates to be applied to the wheel cylinder 6FR and the wheel cylinder 6RL. The hydraulic pressure control unit 44 supplies the calculated motor rotation number to the motor driving unit 52.

  The hydraulic pressure control unit 44 derives an energization current value to each hydraulic pressure adjustment valve from the control characteristics according to the motor rotation speed and the target hydraulic pressure. Here, the “control characteristic” refers to a control characteristic indicating the relationship among the rotation speed of the motor, the current value supplied to each hydraulic pressure adjustment valve, and the hydraulic pressure of the wheel cylinder 6. The control characteristic may be a three-dimensional map. The hydraulic pressure control unit 44 supplies the energization current value to each hydraulic pressure adjustment valve derived to the hydraulic pressure adjustment valve drive unit 54. The hydraulic pressure control unit 44 acquires the wheel cylinder pressure controlled from the hydraulic pressure sensors 13 to 16 based on the energization current value to each hydraulic pressure adjustment valve according to the control characteristics. When the wheel cylinder pressure controlled based on the control characteristics is different from the target hydraulic pressure, the hydraulic pressure control unit 44 calculates a feedback current value by feedback control, and sends the calculated feedback current value to each hydraulic pressure adjustment valve. In addition, the wheel cylinder pressure is adjusted to the target hydraulic pressure. That is, the hydraulic pressure control unit 44 adjusts the hydraulic pressures of the wheel cylinders 6 to the target hydraulic pressures of the respective wheel cylinders 6 by controlling the energization current values to the respective hydraulic pressure adjusting valves based on the control characteristics. When the hydraulic pressure of the wheel cylinder 6 adjusted by the energization current value to each hydraulic pressure adjustment valve based on the control characteristics is different from the target hydraulic pressure of the wheel cylinder 6, the control is made to each hydraulic pressure adjustment valve based on feedback control. Is controlled to adjust the hydraulic pressure of the wheel cylinder 6 to the target hydraulic pressure of the wheel cylinder 6.

  The motor drive unit 52 receives the calculated motor rotation number from the hydraulic pressure control unit 44, and drives the first motor 11 and the second motor 12 according to each motor rotation number.

  The hydraulic pressure adjustment valve drive unit 54 receives the derived energization current value and the calculated feedback current value from the hydraulic pressure control unit 44, drives each hydraulic pressure adjustment valve in accordance with these current values, and opens the valve. Adjust the degree.

  The responsiveness calculation unit 46 calculates the responsiveness (hereinafter sometimes referred to as “pump responsiveness”) of the brake fluid supplied from the pumps 7 to 10 driven by the first motor 11 and the second motor 12. The reference value of the pump responsiveness held in advance is stored in the detected value by simultaneously driving the first motor 11 and the second motor 12 to increase the wheel cylinder pressure to a predetermined predetermined pressure. . By driving the first motor 11 and the second motor 12 simultaneously, the pump 7 and the pump 9 are also driven simultaneously. The responsiveness calculation unit 46 receives the information detected by the acceleration sensor 50 and corrects the reference value of the pump responsiveness held in advance based on the knockback correction value based on the turning history of the vehicle. As a result, the response can be compared based on the response of the brake fluid supply according to the driving situation, and the difference in the braking force generated on the wheels can be reduced by changing the drive timing of the pump. it can. Knock back refers to a phenomenon in which the distance between the brake disk and the brake pad becomes larger than a prescribed distance due to the vibration of the brake disk during vehicle travel, the vibration of the vehicle, and the acceleration applied during turning.

  The delay control unit 48 determines whether to execute delay control. Further, the delay control unit 48 compares the responsiveness of the pump 7 and the pump 9 based on the responsiveness of the pump calculated by the responsiveness calculating unit 46, and provides a delay to the motor corresponding to the pump with fast responsiveness. To decide.

  The pumps 7 and 8 to which the brake fluid is supplied by driving the first motor 11, the wheel cylinders 6 FR and 6 RL, and the pipes connecting them are used as the first system, and the brake fluid is supplied by driving the second motor 12. The pumps 9 and 10, the wheel cylinders 6RR and 6FL, and the pipes connecting them are set as the second system.

  FIG. 3 shows a functional configuration of the hydraulic pressure control unit 44 according to the embodiment. The hydraulic pressure control unit 44 includes a steady motor rotation number calculation unit 91, a consumed liquid amount calculation unit 92, an additional motor rotation number calculation unit 93, an output motor rotation number calculation unit 94, and a feedforward current value derivation unit 95. , A deviation calculation unit 96, a feedback current value deriving unit 97, an output energization current value calculation unit 98, a selection unit 89, and a delay control unit 90.

  The steady motor rotational speed calculation unit 91 receives the target hydraulic pressure Pr for each wheel cylinder 6 from the target hydraulic pressure calculation unit 42, and calculates the steady motor rotational speed based on the target hydraulic pressure Pr. The steady motor rotation speed is a motor rotation speed necessary for maintaining the wheel cylinder pressure at the target hydraulic pressure Pr.

  The consumed fluid amount calculation unit 92 calculates the supply amount of brake fluid necessary for setting the wheel cylinder pressure Pw to the target fluid pressure Pr based on the target fluid pressure Pr. The consumed fluid amount calculation unit 92 calculates the amount of brake fluid that is necessary for the increase and decrease of the wheel cylinder 6 to reach the target fluid pressure Pr based on the supplied amount of brake fluid. The consumed fluid amount calculation unit 92 calculates the brake consumed fluid amount by differentiating the amount of brake fluid corresponding to the increase / decrease with time. The additional motor rotation number calculation unit 93 calculates an additional motor rotation number corresponding to the calculated brake fluid consumption. The output motor rotation speed calculation unit 94 calculates the output motor rotation speed Rout by adding the steady motor rotation speed and the additional motor rotation speed. The output motor rotation number Rout calculated by the output motor rotation number calculation unit 94 is calculated for each wheel cylinder 6 according to the target hydraulic pressure Pr for each wheel cylinder 6.

  Here, in the brake control device 100 of the embodiment, two pumps are operated by driving one motor, and one wheel cylinder is connected to each pump. Therefore, for example, it is necessary to select which output motor rotation speed Rout to drive the first motor 11 out of the output motor rotation speed Rout calculated based on the target hydraulic pressure Pr of the wheel cylinder 6FR and the wheel cylinder 6RL. There is. That is, the motor rotation speed of the first motor 11 is determined based on the target hydraulic pressure Pr of the wheel cylinder 6FR and the wheel cylinder 6RL.

  Therefore, the selection unit 89 selects a larger rotation speed as the output motor rotation speed Rout among the output motor rotation speeds Rout of the same system. The selection unit 89 outputs the selected output motor rotation speed Rout to the delay control unit 90.

  The delay control unit 90 receives the selected output motor rotational speed Rout, and performs control to give a delay to the motor of the same system as the wheel cylinder whose response of the brake is determined to be fast by the response calculation unit 46. The output motor rotation speed Rout of the motor of the same system as the wheel to which the delay is given during the delay control temporarily becomes zero. On the other hand, the delay control unit 90 outputs the selected output motor rotational speed Rout as it is to a motor of the same system as the wheel cylinder whose braking response is determined to be slow by the response calculation unit 46. The delay control unit 90 sends the output motor rotation number Rout to the motor driving unit 52 and the feedforward current value deriving unit 95.

  The feedforward current value deriving unit 95 derives a feedforward current value from the control characteristics based on the target hydraulic pressure Pr and the output motor rotation speed Rout. The feedforward current value is a current value supplied to each hydraulic pressure control valve based on the control characteristics.

  The deviation calculation unit 96 calculates a reference wheel cylinder pressure that is expected from a change over time in the target hydraulic pressure Pr using a predetermined calculation formula. The reference wheel cylinder pressure is a predicted value based on the target hydraulic pressure Pr. The deviation calculation unit 96 calculates the deviation between the wheel cylinder pressure Pw detected from the hydraulic pressure sensors 13 to 16 and the reference wheel cylinder pressure. For example, if the target hydraulic pressure Pr is constant, the reference wheel cylinder pressure also converges to the target hydraulic pressure Pr.

  The feedback current value deriving unit 97 calculates a proportional term, an integral term, and a derivative term of the feedback current based on this deviation. The feedback current value deriving unit 97 calculates the feedback current value by adding the proportional term, the integral term, and the derivative term of the feedback current. The output energization current value calculation unit 98 adds the feedforward current value and the feedback current value, and outputs the added output current value to the hydraulic pressure adjustment valve drive unit 54.

  Thus, in the brake control of the embodiment, first, the motor rotation speed is calculated according to the target hydraulic pressure Pr. Then, for example, the brake fluid is supplied to the wheel cylinder 6FR and the wheel cylinder 6RL according to the motor rotation speed of the first motor 11. The supplied brake fluid is discharged from the hydraulic pressure adjusting valves 32 and 33, respectively, so that the hydraulic pressures of the wheel cylinder 6FR and the wheel cylinder 6RL are maintained at the target hydraulic pressure Pr. That is, in the brake control of the embodiment, the energization current value for maintaining the hydraulic pressure to each hydraulic pressure adjustment valve is determined according to the determined motor rotation speed. Therefore, in the brake control of the brake control device 100, a control characteristic indicating the relationship between the energization current value to each hydraulic pressure adjusting valve and the wheel cylinder pressure at a predetermined motor speed is preferable.

  FIG. 4 shows a map of control characteristics according to the embodiment. The vertical axis represents the energization current of each hydraulic pressure adjustment valve, and the horizontal axis represents the wheel cylinder pressure. The control characteristic indicated by the solid line 65 indicates the control characteristic at the motor rotational speed R1 at which the motor rotational speed is the lowest. I (1, 4) shown in this figure indicates the energization current value at the motor rotation speed R1 and the wheel cylinder pressure P4. This control characteristic map shows the relationship between the energizing current value of each hydraulic pressure regulating valve and the wheel cylinder pressure at a predetermined motor speed R1 to R6. Based on this control characteristic, the hydraulic pressure control unit 44 determines the motor rotation speed and the energization current value of the hydraulic pressure adjustment valve according to the target hydraulic pressure Pr.

  FIG. 5 is a flowchart showing a brake control process according to the embodiment. The process shown in the figure is repeatedly executed at a predetermined control cycle. The target hydraulic pressure calculation unit 42 calculates the target hydraulic pressure Pr (S11). The responsiveness calculation unit 46 reads a reference value of the pump responsiveness held in advance, and performs a process of correcting the responsiveness of the pump according to the knockback correction value based on the turning of the vehicle (S12). The pump responsiveness detection process and the pump responsiveness correction process will be described later.

  The delay control unit 48 determines whether there is a braking request from the driver (S13). The driver's braking request is detected based on at least one of the output of the stroke sensor 2, the hydraulic pressure sensor 18 that can detect the pressure of the master cylinder 3, and the hydraulic pressure sensor 17.

  If there is no braking request from the driver (N in S13), the delay control unit 48 assumes that the delay control is not being performed, and clears the delay control flag (S19). As a result, the delay control is not executed in response to the braking request by the driving support control. Also, when there is a driver's braking request, the braking usually increases the wheel cylinder pressures simultaneously. Note that the delay control flag is lowered when the brake ECU 200 is activated.

  If there is a braking request by the driver (Y in S13), the delay control unit 48 determines whether there is a braking request by the driver in the previous control (S14). That is, it is determined whether or not the current control is when the driver starts a braking request.

  If there is no braking request by the driver in the previous control (N in S14), that is, if the current control is when the driver starts the braking request, the delay control unit 48 determines whether the braking request of the driver is a sudden braking. Whether or not is determined (S15). As a method for determining whether the braking is sudden, the delay control unit 48 may determine based on the brake pedal depression speed, the target deceleration, or the target braking force based on the output of the stroke sensor 2, and the driver's braking request may be determined. When a predetermined sudden braking upper limit is exceeded, it may be determined that the braking is sudden. By determining whether or not the braking is sudden, the magnitudes of the inrush currents of the first motor 11 and the second motor 12 can be estimated.

  If the driver's braking request is sudden braking (Y in S15), the delay control unit 48 determines that the delay control is being performed, and sets a delay control flag (S16). The delay control unit 48 stores the set delay control flag in the memory. Then, the delay control unit 48 sets the delay control time to zero (S17), and decides to give a delay to the motor with fast response (S18).

  Then, the left / right differential pressure correction unit 43 performs a left / right differential pressure correction process on the target hydraulic pressure (S24). Next, the hydraulic pressure control unit 44 calculates the output motor rotation speed and the output energization current value for controlling the brake hydraulic pressure control actuator 5 based on the target hydraulic pressure (S25). If the delay control is being performed, either one of the first motor 11 and the second motor 12 is delayed, and one of the output motor rotational speeds of the first motor 11 and the second motor 12 becomes zero. In other words, the hydraulic pressure control unit 44 starts driving one of the first motor 11 and the second motor 12 whose response is slow before the other motors. In yet another aspect, the hydraulic pressure control unit 44 delays the start of driving of one of the first motor 11 and the second motor 12 that is assumed to have fast response.

  The motor drive unit 52 drives the first motor 11 and the second motor 12 based on the output motor rotational speed, and the hydraulic pressure adjustment valve drive unit 54 drives each hydraulic pressure adjustment valve based on the output energization current value. (S26).

  If the driver's braking request is not sudden braking (N in S15), the processing of S24 to S26 described above is executed with the delay control flag unchanged. If a large braking force is not applied to the rise of the brake, even if the inrush currents of the first motor 11 and the second motor 12 overlap, the inrush current itself is small, so that it is not necessary to delay one of the motors.

  If there is a braking request from the driver in the previous control (Y in S14), that is, if the current braking request is in the middle of a continuous braking request, the delay control unit 48 is performing delay control based on the delay control flag. It is determined whether or not there is (S20). If the delay control is not in progress (N in S20), the processes in S24 to S26 described above are executed.

  If delay control is in progress (Y in S20), the delay control unit 48 adds the control cycle ΔT of this process to the delay control time (S21), and determines whether the delay control time has reached a predetermined delay end time (S21). S22). For example, the predetermined delay end time is set to a time required for the inrush current of the previously driven motor to decrease.

  If the delay control time has not reached the predetermined delay end time (N in S22), the processes of S24 to S26 described above are executed and repeated until the predetermined delay end time is reached. If the delay control time reaches a predetermined delay end time (Y in S22), the delay control unit 48 sets the delay control flag as not being under delay control (S23). Then, the delay control is finished, and the processes of S24 to S26 described above are executed. As described above, the start and end of the delay control are controlled, and a motor having a quick pump response is determined as a motor to which a delay is given.

  FIG. 6 is a flowchart illustrating the delay control according to the embodiment. The process shown in this figure is executed in the process shown in S25 of FIG. In this figure, control of the system corresponding to the first motor 11 is shown, and the control of the system corresponding to the second motor 12 is the same.

  The selection unit 89 selects a larger rotation speed as the output motor rotation speed Rout among the output motor rotation speeds Rout of the same system. Specifically, among the output motor rotation speed Routfr for the right front wheel and the output motor rotation speed Routrl for the left rear wheel, a larger rotation speed is selected as the output motor rotation speed Rout (S2). The selected rotational speed is supplied to the delay control unit 90.

  Next, the delay control unit 90 determines whether delay control is being performed based on the delay control flag (S4). If the delay control is not in progress (N in S4), the delay control unit 90 finishes the delay control and sends the output motor rotational speed Rout as it is.

  If the delay control is being performed (Y in S4), the delay control unit 90 determines whether or not the first motor 11 has been determined to be a motor that gives a delay (S6). If the first motor 11 is not determined to be a motor that gives a delay (N in S6), the delay control unit 90 finishes the delay control and sends the output motor rotational speed Rout as it is.

  If the first motor 11 is determined to be a motor that gives a delay (Y in S6), the delay control unit 90 sets the output motor rotation speed Rout to zero (S8) and outputs the output motor rotation speed Rout.

  As described above, the first timing when the brake fluid is supplied to the wheel cylinders 6 at the same time by making the pump drive start timing different based on the comparison result of the pump responsiveness. It is possible to prevent inrush currents from overlapping when the motor 11 and the second motor 12 are started. Note that if the timing for starting the motor is different, the timing for driving the pump corresponding to the motor also differs depending on the timing for starting the motor.

  FIG. 7 is a flowchart illustrating a pump responsiveness detection process according to the embodiment. This process is repeatedly executed. Further, this process is executed in a factory or the like before shipment of the vehicle. The brake ECU 200 may further include a responsiveness detection unit (not shown) that controls the pump responsiveness detection process.

  The responsiveness detector determines whether or not a pump responsiveness confirmation command has been issued (S29). The pump responsiveness confirmation command may be output from, for example, an external diagnostic machine. The responsiveness detection unit terminates the present process if the pump responsiveness confirmation command has not been issued (N in S29).

  If the pump responsiveness confirmation command has been issued (Y in S29), the hydraulic pressure control unit 44 drives the first motor 11 and the second motor 12 simultaneously with the maximum output in accordance with the command from the responsiveness detection unit ( S30). At this time, the shutoff valves 36 and 37 are closed (S31). That is, the brake fluid discharged from the pump is contained in the wheel cylinder corresponding to the front wheel. By simultaneously driving the first motor 11 and the second motor 12, the difference between the reference values of the responsiveness of the pump 7 and the pump 9 can be obtained with high accuracy. The responsiveness detection unit sets the learning time to zero and starts counting time (S32).

  The response detection unit determines whether the first motor 11 has been learned based on the learned flag (S33). The learned flag is lowered at the initial time. If the first motor 11 has not been learned (N in S33), the response detection unit determines whether the wheel cylinder pressure of the right front wheel is equal to or higher than a predetermined pressure (S34), that is, whether the predetermined pressure has been reached.

  If the wheel cylinder pressure of the right front wheel is smaller than the predetermined pressure (N in S34), the responsiveness detection unit determines whether the second motor 12 has been learned without learning that the first motor 11 has been learned. (S36).

  If the second motor 12 has not been learned (N in S36), the responsiveness detection unit determines whether or not the wheel cylinder pressure of the left front wheel is equal to or higher than a predetermined pressure (S37). If the wheel cylinder pressure of the left front wheel is smaller than the predetermined pressure (N in S37), the responsiveness detection unit adds the control cycle ΔT of the response detection unit to the learning time without assuming that the second motor 12 has already been learned ( S39).

  Next, the response detection unit determines whether or not the first motor 11 and the second motor 12 have been learned (S40). If the first motor 11 and the second motor 12 are not learned (N in S40), the process returns to the process of S33, the wheel cylinder pressure reaches a predetermined pressure, and the first motor 11 and the second motor 12 are learned. Repeat until.

  Returning to S33, if the first motor 11 has been learned (Y in S33), the response detection unit determines whether the second motor 12 has been learned (S36). If the first motor 11 has not been learned (N in S33) and the wheel cylinder pressure of the right front wheel is equal to or higher than the predetermined pressure (Y in S34), the response detection unit has a learning time at that time. Is stored as the responsiveness of the pump corresponding to the first motor 11, the first motor 11 is stopped, and a learned flag is set that the first motor 11 has been learned (S35). Thereby, the responsiveness of the pump 7 driven by the first motor 11 can be detected. Thus, the response of the pump corresponds to the time when the wheel cylinder pressure rises to a predetermined pressure when the motor is driven at the maximum output.

  Similarly, for the second motor 12, if the second motor 12 has already been learned (Y in S36), the response detection unit adds the control period ΔT of the response detection unit to the learning time (S39). If the second motor 12 has not been learned (N in S36) and the wheel cylinder pressure of the left front wheel is equal to or higher than the predetermined pressure (Y in S37), the response detection unit determines the learning time at that time. The responsiveness of the pump 9 driven by the second motor 12 is stored, the second motor 12 is stopped, and a learned flag is set that the second motor 12 has been learned (S38). Thereby, the reference value of the responsiveness of the pump 9 driven by the second motor 12 can be detected. The detected responsiveness reference value is stored in the memory.

  If the first motor 11 and the second motor 12 have already been learned (Y in S40), the responsiveness confirmation command is reset (S41), and this process ends. As described above, the reference value can be obtained with high accuracy by simultaneously driving the motor and obtaining the response of the pump. Note that the response of the pump to the rear wheel can also be acquired by executing the rear wheel. Further, the left / right differential pressure correction unit 43 may execute this process after turning off the ignition switch in order to cope with changes in the motor performance and the pump performance with time.

  FIG. 8 is a flowchart illustrating a correction process of the pump response according to the embodiment. The pump responsiveness correction process shown in the figure is repeatedly executed. Further, the pump responsiveness correction process shown in this figure is a process executed in S12 of FIG.

  When the vehicle is turning, an inertial force acts on the wheels outward in the turning radial direction, while a radially inward frictional force acts on the wheels against the inertial force (hereinafter referred to as the turning radial force). Called “horizontal weight”). For this reason, in a vehicle equipped with a disc brake, the wheel is tilted by the rotational moment due to the inertial force and frictional force, and the disc rotor is also tilted accordingly. As a result, a so-called knockback occurs in which the piston in the caliper is pushed into the cylinder due to the displacement of the disk rotor and the brake pad. When this knockback occurs, the braking force cannot be obtained unless the piston is stroked by the amount that the piston is pushed. In other words, the forward stroke of the piston at the time of the next braking is required more than when there is no knockback. Further, the wheel cylinder pressure is increased in response to the start of driving of the motor, and the initial hydraulic pressure responsiveness can be changed according to the influence of knockback.

  Therefore, the responsiveness calculating unit 46 reads a reference value of the pump responsiveness that is held in advance, and performs a process of correcting the responsiveness reference value according to the knockback correction value based on the turning of the vehicle.

  First, the responsiveness calculation unit 46 determines whether there is a braking request from the driver (S45). The driver's braking request is detected based on at least one of the output of the stroke sensor 2, the hydraulic pressure sensor 18 that can detect the pressure of the master cylinder 3, and the hydraulic pressure sensor 17. If there is a braking request from the driver (Y in S45), the responsiveness calculation unit 46 ends this process.

  If there is no driver braking request (N in S45), the responsiveness calculating unit 46 determines whether or not there is a driver braking request in the previous control cycle (S46). Thereby, the end point of the driver's braking request can be determined.

  If there is a braking request from the driver in the previous control cycle (Y in S46), the responsiveness calculating unit 46 returns the responsiveness of the pump to the reference value that is the initial value, and sets the maximum value of the left and right lateral weights Gy to be initially The value is reset (S52), and this process is terminated. This is because the timing when the braking request from the driver is no longer present is immediately after the end of braking and immediately after the gap between the brake pad and the disc rotor due to knockback is closed.

  If there is no driver braking request in the previous control cycle (N in S46), the responsiveness calculation unit 46 determines whether the lateral weight Gy indicates the right direction of the vehicle (S47). The lateral weight Gy is calculated based on the output of the acceleration sensor 50. Further, the lateral weight Gy has an initial value of zero, a positive value indicates a right lateral load, and a negative value indicates a left lateral weight.

  If the lateral weight Gy indicates the right direction of the vehicle (Y in S47), the responsiveness calculating unit 46 updates the maximum right lateral weight value GyRMAX (S48). Specifically, the responsiveness calculating unit 46 sets a larger value as the maximum right lateral weight value GyRMAX among the lateral weight Gy acquired from the acceleration sensor 50 and the currently held maximum right lateral weight value GyRMAX. Hold.

  On the other hand, if the lateral weight Gy indicates the left direction of the vehicle (N in S47), the responsiveness calculation unit 46 performs the update process of the left lateral weight maximum value GyLMAX (S49). Specifically, the responsiveness calculation unit 46 calculates a larger value among the value −Gy obtained by returning the lateral weight Gy acquired from the acceleration sensor 50 to a positive value and the maximum left lateral weight value GyLMAX held. Is held as the maximum value GyLMAX of the left lateral weight.

  Then, the responsiveness calculation unit 46 calculates the first knockback correction value and the second knockback correction value based on the maximum value GyRMAX of the right lateral weight, the maximum value GyLMAX of the left lateral weight, and the lateral weight Gy at the time of the current control. Calculate (S50). The first knockback correction value is a correction value for correcting the response of the pump 7, and the second knockback correction value is a correction value for correcting the response of the pump 9. When the vehicle returns to straight running after turning, the piston of the disc brake unit pushed in by turning also returns slightly. Therefore, the knockback correction value is calculated using not only the maximum lateral weight but also the lateral weight Gy at the time of the current control.

  Specifically, a method for calculating the first knockback correction value will be described. The responsiveness calculating unit 46 calculates the first knockback correction value from the right lateral weight maximum value GyRMAX, the left lateral weight maximum value GyLMAX, and the lateral weight Gy at the current control time using a predetermined function. . The predetermined function is illustrated below.

  FIG. 9 and FIG. 10 are diagrams illustrating functions for calculating the knockback correction value according to the embodiment. FIG. 9 shows a function (hereinafter referred to as “outer wheel function”) for a wheel (hereinafter referred to as “outer wheel”) positioned on the outside when the vehicle is turning, and FIG. (This function is called “inner ring function”). 9 and 10, the vertical axis indicates the knockback correction value, and the horizontal axis indicates the horizontal weight Gy.

  Also, the three functions 60, 61, and 62 shown in FIG. 9 indicate functions that change in accordance with the maximum value of the lateral weight. If the maximum value of the lateral weight is large, the function 60 is obtained. If the maximum value of the horizontal weight is small, the function 62 is obtained. That is, the functions 60 to 62 shown in FIG. 9 are functions in which the maximum value of the lateral weight is already determined, and the knockback correction value increases as the maximum value of the lateral weight increases. . FIG. 10 also shows three functions in which the maximum value of the lateral weight is determined as in FIG. Since the outer ring is more greatly affected by the knockback due to the inertial force, the knockback correction value for the outer ring is larger than the knockback correction value for the inner ring. Further, since the directions of the pistons to be pushed are opposite between the outer ring and the inner ring, the direction of the lateral load Gy in which the knockback correction value increases in the outer ring function in FIG. 9 and the inner ring function in FIG. 10 is different.

  The responsiveness calculating unit 46 calculates the outer wheel first knockback correction value by substituting the right lateral weight maximum value GyRMAX and the lateral weight Gy at the current control time into the outer wheel function. Then, the responsiveness calculating unit 46 calculates the inner ring first knockback correction value by substituting the maximum value GyLMAX of the left lateral weight and the lateral weight Gy at the time of the current control into the inner ring function. The responsiveness calculation unit 46 calculates a larger value as the first knockback correction value among the outer ring first knockback correction value and the inner ring first knockback correction value.

  The responsiveness calculating unit 46 multiplies the lateral weight Gy to a positive value, and uses the left lateral weight maximum value GyLMAX for the outer ring function and the right lateral weight maximum value GyRMAX for the inner ring function. The second knockback correction value is calculated in the same manner as the first knockback correction value.

  Then, the responsiveness calculating unit 46 adds the first knockback correction value to the responsiveness reference value of the pump 7 to calculate the responsiveness of the pump 7, and then adds the second knocking value to the responsiveness reference value of the pump 9. The back correction value is added to calculate the response of the pump 9 (S51). In this way, by correcting the pump responsiveness according to the influence of the knockback caused by the traveling history of the vehicle, it is possible to calculate the pump responsiveness according to the driving situation. Furthermore, the left-right difference of the braking force which generate | occur | produces on a wheel can be made small by starting from a pump with slow response based on the response of the pump according to the situation more.

  FIG. 11 is a flowchart illustrating the left-right differential pressure correction process according to the embodiment. The left / right differential pressure correction process shown in the figure is repeatedly executed. Further, the left-right differential pressure correction process shown in this drawing is a process executed in S24 of FIG. In this process, the left / right differential pressure correction unit 43 corrects the target hydraulic pressure so as to relieve the differential pressure between the left and right wheel cylinder pressures generated by the delay control and the target hydraulic pressure of the wheel cylinders. The left and right wheel cylinder pressures refer to, for example, the left front wheel wheel cylinder pressure and the right front wheel wheel cylinder pressure.

  First, the left / right differential pressure correction unit 43 calculates a differential pressure ΔP obtained by subtracting the wheel cylinder pressure from the target hydraulic pressure (S55). The left / right differential pressure correction unit 43 calculates a right front wheel differential pressure ΔPfr and a left front wheel differential pressure ΔPfl.

  Then, the left / right differential pressure correction unit 43 determines whether the product of the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is greater than or equal to zero (S56). If the product of the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is negative (N in S56), the left / right differential pressure correction unit 43 ends this process. This is because if the product of the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is a negative value, one is increased and the other is reduced, so there is no need for correction. Due to the delay control, the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl may both have the same sign.

  If the product of the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is greater than zero (Y in S56), the left / right differential pressure correction unit 43 determines that the right / left differential pressure correction unit 43 has a right front wheel differential pressure ΔPfr and a left front wheel differential. It is determined whether or not the absolute value of the difference from the pressure ΔPfl is greater than a predetermined first threshold value Th1 (S57). That is, the left / right differential pressure correction unit 43 determines whether or not a deviation that requires correction is generated in both differential pressures.

  If the absolute value of the difference between the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is less than or equal to the predetermined first threshold value (N in S57), the left / right differential pressure correction unit 43 ends this process. For example, immediately after the start of the delay control, if any wheel cylinder pressure is hardly increased, the absolute value of the difference can be equal to or less than a predetermined first threshold value.

  If the absolute value of the difference between the right front wheel differential pressure ΔPfr and the left front wheel differential pressure ΔPfl is greater than a predetermined first threshold (Y in S57), the left / right differential pressure correction unit 43 determines that the absolute value of the right front wheel differential pressure ΔPfr is left It is determined whether the front wheel differential pressure ΔPfl is greater than the absolute value (S58). When the delay control is performed, it can be estimated that the absolute value of the differential pressure ΔP of the system of the motor to which the delay is given is large.

  If the absolute value of the right front wheel differential pressure ΔPfr is greater than the absolute value of the left front wheel differential pressure ΔPfl (Y in S58), the left / right differential pressure correction unit 43 is performing delay control, and the motor to which the delay is applied is the first. It is determined whether or not the motor 11 (S59). Thereby, it is because the delay was given to the 1st motor 11 that the absolute value of right front wheel differential pressure (DELTA) Pfr became large, and it can confirm that the 1st motor 11 has stopped. The left / right differential pressure correction unit 43 determines whether or not the delay control is being performed based on the delay control flag.

  If the delay control is being performed and the motor to which the delay is applied is the first motor 11 (Y in S59), the left / right differential pressure correction unit 43 sets the left front wheel differential pressure ΔPfl multiplied by the correction coefficient α to the left Subtract from the target hydraulic pressure Prfl of the front wheels (S65). The correction coefficient α satisfies 0 <α <1. That is, the left / right differential pressure correction unit 43 corrects the target hydraulic pressure Prfl of the left front wheel so as to reduce the absolute value of the left front wheel differential pressure ΔPfl. Here, in order to relieve the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure of the wheel cylinders, for example, the wheel cylinder pressure previously increased by delay control is corrected so as to approach the delayed one. If the delay control is being performed, since the first motor 11 is stopped, the target hydraulic pressure of the left front wheel that can adjust the left-right differential pressure is corrected. As a result, the difference in braking force applied to the left and right wheels can be reduced.

  When the delay control is being performed and the motor to which the delay is applied is not the first motor 11 (N in S59), the left / right differential pressure correction unit 43 determines that the absolute value of the right front wheel differential pressure ΔPfr is a predetermined second threshold Th2. It is determined whether it is smaller (corresponding to “predetermined range”) (S60). As a result, it can be determined whether or not the delay of the pressure increase of the right front wheel that is delayed is within a normal range. Hereinafter, the predetermined second threshold value indicating the normal range will be described.

  FIG. 12 is a diagram illustrating a predetermined second threshold value according to the embodiment. The predetermined second threshold value is calculated by the function shown in the figure, and is determined based on the target hydraulic pressure gradient and the motor power supply voltage. The function shown in this figure defines the power supply voltage of the motor.

  If the power supply voltage of the motor is low, a function 66 that is a relatively high second threshold at the time of pressure increase is used, and the normal range is widened. On the other hand, if the power supply voltage of the motor is high, a function 67 that is a second threshold value that is relatively low when the pressure is increased is used, and the normal range is narrowed. This is because if the power supply voltage of the motor is low at the time of pressure increase, the amount of brake fluid that can be supplied to the wheel cylinder 6 is small even if the motor is driven at the maximum output, so that the normal range needs to be enlarged. If the differential pressure ΔP is not within the normal range, the left / right differential pressure correction unit 43 may assume that there is some malfunction in the control system. As described above, in S60, it is determined whether or not the wheel cylinder pressure is appropriate from the braking request of the driver and the output upper limit value of the motor.

  If the absolute value of the right front wheel differential pressure ΔPfr is smaller than a predetermined second threshold (Y in S60), the left / right differential pressure correction unit 43 determines whether the wheel cylinder pressure of the right front wheel is increased or decreased at the maximum output ( S61). In the case of sudden braking, a motor to which a delay is given during delay control may be driven at the maximum output. The wheel cylinder pressure being increased at the maximum output means a state in which the number of rotations of the motor is maximum and the hydraulic pressure adjustment valve is closed. Further, the wheel cylinder pressure being reduced at the maximum output means a state in which the number of rotations of the motor is zero and the energization current value to the hydraulic pressure adjustment valve is maximum.

  If the wheel cylinder pressure of the right front wheel is increased or decreased at the maximum output (Y in S61), the left / right differential pressure correction unit 43 multiplies the left front wheel differential pressure ΔPfl by the correction coefficient α to obtain the target hydraulic pressure of the left front wheel. Subtract from Prfl (S65). If the wheel cylinder pressure of the right front wheel is increased or reduced at the maximum output, it cannot be output any more, so the target hydraulic pressure Prfl of the left front wheel corresponding to the motor driven in advance is corrected.

  On the other hand, if the absolute value of the right front wheel differential pressure ΔPfr is equal to or greater than the predetermined second threshold (N in S60), the left / right differential pressure correction unit 43 sets a value obtained by multiplying the right front wheel differential pressure ΔPfr by the correction coefficient β to the right front wheel. Is added to the target hydraulic pressure Prfr (S66). That is, the left / right differential pressure correction unit 43 corrects the target hydraulic pressure Prfr of the right front wheel so as to reduce the absolute value of the right front wheel differential pressure ΔPfr. Here, in order to relieve the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure of the wheel cylinders, for example, the wheel cylinder pressure of the system with a delay is corrected so as to be closer to the one driven in advance. . The correction coefficient β satisfies β> 0. The correction coefficient β may be determined according to the magnitude of the differential pressure ΔP used for correction, and may be set to a relatively large value if the differential pressure ΔP is large.

  If the wheel cylinder pressure of the right front wheel is not increased or reduced at the maximum output (N in S61), the left / right differential pressure correction unit 43 multiplies the right front wheel differential pressure ΔPfr by the correction coefficient β to obtain the target value for the right front wheel. Add to the hydraulic pressure Prfr (S66). If the wheel cylinder pressure of the right front wheel is not increased or decreased at the maximum output, the output relative to the wheel cylinder pressure of the right front wheel can be adjusted. Therefore, the left / right differential pressure correction unit 43 determines the left and right wheel cylinder pressures and the target of the wheel cylinders based on the difference between the target hydraulic pressure of the wheel cylinders and the wheel cylinder pressure. Correct so as to reduce the differential pressure from the hydraulic pressure. By adjusting the target hydraulic pressure corresponding to the motor driven as late as possible, the differential pressure generated in the left and right wheel cylinder pressures can be reduced so as not to impair the vehicle braking response. As described above, the case where the absolute value of the right front wheel differential pressure ΔPfr is greater than the left front wheel differential pressure ΔPfl has been described.

  If the absolute value of the right front wheel differential pressure ΔPfr is not greater than the absolute value of the left front wheel differential pressure ΔPfl (N in S58), the left / right differential pressure correction unit 43 is performing delay control and the motor to which the delay is applied is the first. It is determined whether or not the motor 2 is used (S62).

  When the delay control is being performed and the motor to which the delay is applied is the second motor 12 (Y in S62), the left / right differential pressure correction unit 43 multiplies the right front wheel differential pressure ΔPfr by the correction coefficient α to the right. Subtract from the target hydraulic pressure Prfr of the front wheels (S67).

  When the delay control is being performed and the motor to which the delay is applied is not the second motor 12 (N in S62), the left / right differential pressure correction unit 43 determines that the absolute value of the left front wheel differential pressure ΔPfl is greater than a predetermined second threshold value. It is determined whether it is small (S63).

  If the absolute value of the left front wheel differential pressure ΔPfl is smaller than a predetermined second threshold (Y in S63), the left / right differential pressure correction unit 43 determines whether the wheel cylinder pressure of the left front wheel is increased or decreased at the maximum output ( S64).

  If the wheel cylinder pressure of the left front wheel is increased or decreased at the maximum output (Y in S64), the left / right differential pressure correction unit 43 multiplies the right front wheel differential pressure ΔPfr by the correction coefficient α to obtain the target hydraulic pressure of the right front wheel. Subtract from Prfr (S67).

  On the other hand, if the absolute value of the left front wheel differential pressure ΔPfl is greater than or equal to a predetermined second threshold value (N in S63), the left / right differential pressure correction unit 43 sets a value obtained by multiplying the left front wheel differential pressure ΔPfl by the correction coefficient β to the left front wheel. Is added to the target hydraulic pressure Prfl (S68).

  If the wheel cylinder pressure of the left front wheel is not increased or decreased at the maximum output (N in S64), the left / right differential pressure correction unit 43 multiplies the left front wheel differential pressure ΔPfl by the correction coefficient β to obtain the target value for the left front wheel. Add to the hydraulic pressure Prfl (S68). In addition to the correction method shown in S65 to S68, for example, a correction method described in Japanese Patent Application Laid-Open No. 2005-14883 or Japanese Patent Application Laid-Open No. 2006-117128 may be used.

  As described above, it is possible to alleviate the difference between the systems in which the difference between the target hydraulic pressure and the wheel cylinder pressure is large. In addition, the difference in braking force to the left and right wheels caused by delay control can be alleviated except when the motor is at maximum output or when the motor is stopped, and the response to braking requests is impaired as much as possible. It can be corrected so that there is no. If the delay control is executed when the driver suddenly depresses the brake pedal, the difference in braking force between the left and right wheels may increase. In such a case, the brake ECU 200 causes the wheel cylinder pressure of the system to which the delay is applied to increase. It can be adjusted to catch up with the wheel cylinder pressure of the previously driven system.

  By the way, since there is a difference in the braking force applied to the front and rear wheels, when the delay control is executed, a difference occurs in the braking force applied to the front and rear wheels as compared to the normal braking control. Therefore, the brake ECU 200 according to the embodiment, when shifting the drive start timing of the pump 7 and the pump 9, causes a difference in braking force generated between the two diagonal wheels to which the brake fluid is supplied by the pump driven in advance. A distribution correction process is performed to correct the target hydraulic pressure so as to be smaller than a predetermined braking force difference.

  FIG. 13 is a schematic diagram illustrating the braking force applied to each wheel. FIG. 13 (a) shows the braking force applied to each wheel during normal operation, FIG. 13 (b) shows the braking force applied to each wheel immediately after execution of the delay control, and FIG. 13 (c) shows the embodiment. The braking force applied to each wheel immediately after the execution of the delay control that has been subjected to the distribution correction process is shown. In each of the vehicles shown in FIGS. 13A to 13C, the upper side of the drawing is the front of the vehicle.

  During normal braking shown in FIG. 13A, an arrow 70 indicating the magnitude of the braking force applied to the wheel is equally applied to the right front wheel and the left front wheel. Although the braking force applied to the front wheels and the rear wheels is different, the braking force applied to the left and right wheels is equal. In this state, almost no force in the yaw direction is generated in the vehicle body.

  On the other hand, at the time of braking immediately after the delay control shown in FIG. 13B, almost no braking force is applied to the left front wheel and the right rear wheel of the same system as the second motor 12 to which the delay is given, and the first motor A braking force is applied to the right front wheel and the left rear wheel of the same system as that of No. 11. In the brake control device 100 according to the embodiment, two wheel cylinders to which brake fluid is supplied by one motor are located at the diagonal of the vehicle (hereinafter referred to as “diagonal two wheels”). Therefore, the braking force 72 applied to the right front wheel is greater than the braking force 73 applied to the left rear wheel, and the braking force applied to the left and right wheels is different. At this time, a force 71 in the yaw direction can be generated in the vehicle.

  Therefore, as shown in FIG. 13C, the brake ECU 200 distributes the braking force applied to the two diagonal wheels so as to be substantially equal during the delay control and during the braking immediately thereafter. That is, when the start timing of driving of the pump 7 and the pump 9 is shifted, the brake ECU 200 calculates the difference in braking force generated between the two diagonal wheels to which the brake fluid is supplied by the motor driven in advance. It is made smaller than a predetermined braking force difference. The braking force 76 applied to the right front wheel and the braking force 75 applied to the left rear wheel are substantially equal, and the braking force applied to the left and right wheels is also substantially equal. Therefore, the force 74 in the yaw direction generated in the vehicle is reduced so as to be hardly generated as compared with the state shown in FIG. This specific control will be described below.

  FIG. 14 is a flowchart illustrating distribution correction processing according to the embodiment. The distribution correction process shown in the figure is repeatedly executed. In addition, the case where it combines with the control shown in FIG. 5 is also demonstrated.

  The delay control unit 48 sets a distribution correction processing flag on the assumption that the distribution correction processing is being performed when delay control is started (S70). When combined with the control shown in FIG. 5, the process of S70 may be executed between S16 and S17 of FIG. The following series of processing from S71 to S76 may be executed after S18 and S23 in FIG. 5 and before S24.

  The hydraulic pressure control unit 44 determines whether delay control is being performed (S71). When delay control is being performed (Y in S71), the hydraulic pressure control unit 44 determines whether distribution correction processing is being performed (S75). If the delay control is not in progress (N in S71), the hydraulic pressure control unit 44 determines whether the absolute value of the difference between the target hydraulic pressure Prfr for the right front wheel and the target hydraulic pressure Prfl for the left front wheel is smaller than a predetermined third threshold Th3. Determine (S72). In this determination, it is determined whether or not there is a difference between the target hydraulic pressures of the left and right wheels, and it is determined whether or not the braking force distribution during the turning of the vehicle is being executed. If there is a difference between the target hydraulic pressures of the left and right wheels, the braking force distribution at the time of turning of the vehicle is executed, so that the distribution correction process does not hinder the braking force distribution at the time of turning.

  If the absolute value of the difference between the target hydraulic pressure Prfr for the right front wheel and the target hydraulic pressure Prfl for the left front wheel is greater than a predetermined third threshold value (Y in S72), the hydraulic pressure control unit 44 determines that the distribution correction process is not being performed and performs distribution correction. The processing flag is lowered (S73).

  If the absolute value of the difference between the target hydraulic pressure Prfr for the right front wheel and the target hydraulic pressure Prfl for the left front wheel is equal to or smaller than a predetermined third threshold value (N in S72), the hydraulic pressure control unit 44 determines the wheel cylinder pressure Pwfr for the right front wheel. It is determined whether the absolute value of the difference between the wheel cylinder pressure Pwr1 of the left front wheel and the left front wheel is smaller than a predetermined fourth threshold value Th4 (S74). In this determination, it is determined whether there is a difference between the wheel cylinder pressures of the two front wheels. The fourth threshold value corresponds to a predetermined pressure value.

  If the absolute value of the difference between the wheel cylinder pressure Pwfr for the right front wheel and the wheel cylinder pressure Pwfl for the left front wheel is smaller than the fourth threshold value (Y in S74), the hydraulic pressure control unit 44 determines that the distribution correction process is not being performed and performs the distribution correction process. The flag is lowered (S73). If the absolute value of the difference between the wheel cylinder pressure Pwfr for the right front wheel and the wheel cylinder pressure Pwfl for the left front wheel is equal to or greater than the fourth threshold value (N in S74), the hydraulic pressure control unit 44 leaves the distribution correction processing flag as it is. . The conditions of S72 and S74 are the end conditions of the distribution correction process. Then, after these processes, distribution correction is executed.

  The hydraulic pressure control unit 44 determines whether the distribution correction process is in progress (S75). If the distribution correction process is being performed (Y in S75), the hydraulic pressure control unit 44 corrects the distribution of the target hydraulic pressure of the two diagonal wheels (S76). In other words, if the delay control is being performed and immediately after the execution of the delay control, braking force distribution correction processing for the two diagonal wheels is executed. If the distribution correction process is not in progress (N in S75), the hydraulic pressure control unit 44 ends this process without performing distribution correction.

  The correction for allocating the target hydraulic pressure so that the braking forces of the two diagonal wheels are substantially equal will be specifically described. FIG. 15 is a diagram illustrating the distribution of the braking force in the distribution correction process according to the embodiment. The vertical axis of this figure shows the braking force distributed to the rear wheels, and the horizontal axis shows the braking force distributed to the front wheels.

  In this figure, the solid line 79 indicates the braking force distribution at the normal time, and the solid line 78 indicates the braking force distribution in the distribution correction process. The broken line indicates the distribution in which the rear wheel braking force and the front wheel braking force are equal. When the braking force increases to some extent, the delay control executed at the start of braking is completed, so the normal braking force distribution indicated by the solid line 79 and the braking force distribution in the distribution correction processing indicated by the solid line 78 are the same. On the other hand, when the braking force is relatively small, there is a possibility that the left and right braking force may be different due to the delay control, so the hydraulic pressure control unit 44 greatly corrects the braking force distribution compared to when the braking force is large. Then, the braking force applied to the two diagonal wheels is distributed so as to be substantially equal.

  For example, when the braking force distribution is point 80, the hydraulic pressure control unit 44 corrects the braking force distribution to be point 81 so that the distribution of the front wheels and the rear wheels approaches the equal distribution. The hydraulic pressure control unit 44 corrects the distribution so that the sum of the braking forces of the front wheels and the rear wheels is kept constant before and after the distribution correction. By correcting the braking force distribution as described above, the moment in the yaw direction that can be generated in the vehicle by the delay control can be reduced.

  Control results of the brake control device 100 according to the embodiment described above will be described with reference to FIGS. FIG. 16 is a diagram illustrating a conventional brake control result. FIG. 17 is a diagram illustrating a brake control result in which a delay is given to the second motor 12 according to the embodiment. FIG. 18 is a diagram illustrating a brake control result in which a delay is given to the first motor 11 according to the embodiment. FIG. 19 is a diagram illustrating a brake control result in which a delay is given to the first motor 11 according to the embodiment and a right / left differential pressure correction process is executed.

  16A to 19A show the hydraulic pressure control results, and FIGS. 16 to 19B show the motor control results. 16 to 19, the vertical axis indicates the hydraulic pressure, and the horizontal axis indicates time. 16 to 19B, the vertical axis indicates the current supplied to the motor, and the horizontal axis indicates time. 16 to 19, it is assumed that the pump 9 is slower in pump response than the pump 7.

  In FIG. 16A, the wheel cylinder pressure Pwfr for the right front wheel and the wheel cylinder pressure Pwfl for the left front wheel are generated with a slight delay from the target hydraulic pressure Pr for the right front wheel and the left front wheel. Here, the wheel cylinder pressure Pwfr of the right front wheel is more responsive than the wheel cylinder pressure Pwfl of the left front wheel.

  In FIG. 16B, the same amount of current is supplied to the first motor 11 and the second motor 12, and the total of the current is very large at the start of braking due to the inrush current overlap.

  In FIG. 17B, a delay is given to the second motor 12, and the drive start timings of the first motor 11 and the second motor 12 are shifted, so the total current is shown in FIG. It is reduced compared to the total current shown.

  However, in FIG. 17A, since the delay is given to the second motor 12 having a slow pump response, the wheel cylinder pressure Pwfl of the left front wheel does not catch up with the wheel cylinder pressure Pwfr of the right front wheel.

  In FIG. 18B, a delay is given to the first motor 11 and the drive start timings of the first motor 11 and the second motor 12 are shifted, so the total current is shown in FIG. It is reduced compared to the total current shown.

  In FIG. 18A, since the delay is given to the first motor 11, the wheel cylinder pressure Pwfl of the left front wheel, which is a system with slow pump responsiveness, is boosted ahead of the wheel cylinder pressure Pwfr of the right front wheel. is doing. However, after that, the wheel cylinder pressure Pwfr of the right front wheel quickly catches up with the wheel cylinder pressure Pwfl of the left front wheel. The control result shown in FIG. 18A can reduce the difference between the wheel cylinder pressure Pwfr for the right front wheel and the wheel cylinder pressure Pwfl for the left front wheel, compared to the control result shown in FIG.

  In FIG. 19B, as in FIG. 18B, a delay is given to the first motor 11 and the drive start timings of the first motor 11 and the second motor 12 are shifted. Is reduced as compared with the total current shown in FIG.

  In FIG. 19A, since the left-right differential pressure correction process is performed, the wheel cylinder pressure of the left front wheel is changed to the corrected target hydraulic pressure Prfl obtained by correcting the uncorrected target hydraulic pressure Pr. It is controlled on the basis. Since the corrected target hydraulic pressure Prfl is driven in advance, the corrected target hydraulic pressure Prfl is corrected to be smaller than the target hydraulic pressure Pr before correction immediately after the start of braking, and then overtaken by the wheel cylinder pressure Pwfr of the right front wheel. The correction is made to be larger than the target hydraulic pressure Pr before correction. By performing the left-right differential pressure correction process, the wheel cylinder pressure Pwfr for the right front wheel and the wheel cylinder pressure Pwfl for the left front wheel are quickly equalized.

  The present invention is not limited to the above-described embodiment, and an appropriate combination of the elements of the embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added can be included in the scope of the present invention. . The configuration shown in each figure is for explaining an example, and any configuration that can achieve the same function can be changed as appropriate, and the same effect can be obtained.

  DESCRIPTION OF SYMBOLS 1 Brake pedal, 2 Stroke sensor, 3 Master cylinder, 3a Primary chamber, 3b Secondary chamber, 3c Primary piston, 3d Secondary piston, 3e Spring, 3f Reservoir tank, 4 Stroke simulator, 5 Brake hydraulic pressure control actuator, 6FL, 6FR , 6RL, 6RR, wheel cylinder, 7, 8, 9, 10 pump, 11 first motor, 12 second motor, 13, 14, 15, 16, 17, 18 hydraulic pressure sensor, 20, 21 check valve, 30 Stroke control valve, 32, 33, 34, 35 Fluid pressure regulating valve, 36, 37 Shutoff valve, 38, 39 Communication valve, 42 Target fluid pressure calculation unit, 43 Left / right differential pressure correction unit, 44 Fluid pressure control unit, 46 Response Sex calculation unit, 48 delay control unit, 50 add Speed sensor, 52 motor drive unit, 54 hydraulic pressure control valve drive unit, 89 selection unit, 90 delay control unit, 91 steady motor rotation speed calculation unit, 92 consumption liquid volume calculation unit, 93 additional motor rotation speed calculation unit, 94 output Motor rotation number calculation unit, 95 feed forward current value deriving unit, 96 deviation calculation unit, 97 feedback current value deriving unit, 98 output energization current value calculation unit, 100 brake control device, 200 brake ECU.

Claims (11)

A brake control device that applies braking force to a wheel by supplying brake fluid to a wheel cylinder via a hydraulic circuit,
A plurality of pumps for supplying brake fluid to the wheel cylinders according to driving through a hydraulic pressure source provided in the hydraulic pressure circuit;
Controlling the supply of brake fluid to the wheel cylinder by driving the pump, and a control means for comparing the response of the supply of brake fluid by the plurality of pumps,
The said control means changes the timing of the drive start of the said pump based on the comparison result of the response of the supply of the brake fluid by the said several pump, The brake control apparatus characterized by the above-mentioned.   2. The brake control device according to claim 1, wherein the control unit drives the pump determined to be slow in response among the plurality of pumps based on the comparison in advance of the other pumps.   2. The brake control device according to claim 1, wherein the control unit delays the start of driving of the pump that is determined to be fast in response among the plurality of pumps based on the comparison.   The brake fluid is supplied to each of the wheel cylinders corresponding to the wheels on the left and right sides of the vehicle by driving each of the plurality of motors that drive the pump. Brake control device.   The control means retains responsiveness of supply of brake fluid by the plurality of pumps, and performs the comparison by correcting the responsiveness based on a knockback correction value according to turning of the vehicle. The brake control device according to any one of claims 1 to 4.   The brake control according to any one of claims 1 to 5, wherein the control means detects the responsiveness of the supply of brake fluid by the plurality of pumps to be held by simultaneously driving the plurality of pumps. apparatus.   The control means determines the target hydraulic pressure corresponding to the pump driven with a delay based on the difference between the target hydraulic pressure of the wheel cylinder and the wheel cylinder pressure, and the difference between the left and right wheel cylinder pressures and the target hydraulic pressure. The brake control device according to claim 1, wherein the pressure is corrected so as to relieve the pressure.   When the output of the pump driven with a delay is maximum, the control means determines the target hydraulic pressure corresponding to the pump driven in advance as the differential pressure between the left and right wheel cylinder pressures and the target hydraulic pressure. The brake control device according to any one of claims 1 to 7, wherein correction is performed so as to relax the vibration.   The control means, when the difference between the target hydraulic pressure of the wheel cylinder corresponding to the pump driven with a delay and the wheel cylinder pressure is within a predetermined range, the target liquid corresponding to the pump driven in advance The brake control device according to any one of claims 1 to 8, wherein the pressure is corrected so as to relieve a differential pressure between a left and right wheel cylinder pressure and the target hydraulic pressure.   The brake fluid is supplied to the wheel cylinder corresponding to the two wheels on the diagonal of the vehicle by driving one motor that drives the pump. Brake control device.   When the control means shifts the drive start timings of the plurality of pumps, a difference in braking force generated between two diagonal wheels supplied with brake fluid by the motor corresponding to the pump driven in advance. The brake control device according to claim 10, wherein the target hydraulic pressure of the wheel cylinder is corrected so as to be smaller than a predetermined braking force difference.

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