JP2017171203A - Vehicular brake fluid pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a timing of estimating a road surface μ earlier.SOLUTION: A vehicular brake fluid pressure control device includes a wheel deceleration degree calculation means 110 for calculating a wheel deceleration degree of each wheel, a wheel cylinder pressure acquiring means (wheel cylinder pressure estimating means 120) for acquiring a wheel cylinder pressure of a front wheel, and a high μ path determination means 130 which determines whether or not a road surface is a high μ path based on the front wheel cylinder pressure acquired by the wheel cylinder pressure acquiring means and the wheel deceleration degree of each wheel that is calculated by the wheel deceleration degree calculation means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle brake hydraulic pressure control device.

  2. Description of the Related Art Conventionally, as a vehicle brake fluid pressure control device, vehicle deceleration is estimated based on wheel speeds during vehicle braking, and a road surface friction coefficient (hereinafter also referred to as “road surface μ”) is estimated based on the estimated vehicle deceleration. Is known (see Patent Document 1). Specifically, in this technique, the road surface μ is estimated by acquiring the wheel speed at the start of the pressure increase control in the antilock brake control (hereinafter also referred to as “ABS control”) at least twice.

JP 2013-71657 A

  However, since the road surface μ is estimated after the pressure increase control is performed twice in the related art, there is a problem that the timing for estimating the road surface μ is delayed.

  Accordingly, an object of the present invention is to speed up the timing for estimating the road surface μ.

  In order to solve the above-described problem, a vehicle brake hydraulic pressure control device according to the present invention includes a wheel deceleration calculating unit that calculates a wheel deceleration of each wheel, and a wheel cylinder pressure acquiring unit that acquires a wheel cylinder pressure of a front wheel. Based on the wheel cylinder pressure of the front wheel acquired by the wheel cylinder pressure acquisition means and the wheel deceleration of each wheel calculated by the wheel deceleration calculation means, it is determined whether or not the road surface is a high μ road. High μ road determination means.

  According to this configuration, since it is determined whether or not the road is a high μ road based on the wheel cylinder pressure of the front wheels and the wheel deceleration of each wheel, the road surface μ is determined at the start of the ABS control pressure reduction control. Can do.

  In the above-described configuration, the high μ road determination means is such that the wheel cylinder pressures of the left and right front wheels are not less than the first threshold value, and the absolute values of the wheel deceleration of each wheel are all not less than the second threshold value. In some cases, it may be configured to determine that the road is a high μ road.

  According to this, the road surface μ can be accurately determined. The fact that the wheel cylinder pressures of the left and right front wheels are equal to or higher than the first threshold indicates that the wheel cylinder pressures are not reduced by the intervention of ABS control, that is, the road surface is not a low μ road. This means that the road surface μ is a high value to some extent. Further, the fact that the absolute values of the wheel deceleration of each wheel are all equal to or greater than the second threshold means that the ground contact surface of each wheel is the same high μ road.

  Further, in the above-described configuration, when the high μ road determination unit determines that the road is a high μ road, the intervention threshold of the pressure reduction control in the antilock brake control is larger than the case where it is determined that the road is not a high μ road. You may provide the threshold value setting means set to a value.

  According to this, when it is determined that the road is a high μ road, the intervention threshold of the pressure reduction control in the antilock brake control becomes a large value (that is, a value that is difficult to intervene in the pressure reduction control). The timing at which the lock brake control is started can be delayed.

  Further, in the above-described configuration, when the high μ road determination unit determines that the road is a high μ road, the pressure reduction amount of the pressure reduction control in the antilock brake control is smaller than that when it is determined that the road is not a high μ road. It may be set to a value.

  According to this, when it is determined that the road is a high μ road, the pressure reduction amount of the pressure reduction control in the antilock brake control becomes a small value, so that excessive pressure reduction on the high μ road can be suppressed. .

  According to the present invention, the timing for estimating the road surface μ can be advanced.

1 is a configuration diagram of a vehicle including a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. It is a block diagram which shows the structure of a hydraulic unit. It is a block diagram which shows the structure of a control part. It is a flowchart which shows operation | movement of a control part. It is time chart (a)-(c) which shows an example of operation | movement of a control part.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the vehicle brake fluid pressure control device 1 is a device that appropriately controls the braking force applied to each wheel 3 of the vehicle 2. The vehicular brake hydraulic pressure control device 1 mainly includes a hydraulic unit 10 provided with an oil passage and various components, and a control unit 100 for appropriately controlling various components in the hydraulic unit 10.

  Each wheel 3 is provided with a wheel brake FL, RR, RL, FR, and each wheel brake FL, RR, RL, FR is braked by a hydraulic pressure supplied from a master cylinder 5 as a hydraulic pressure source. A wheel cylinder 4 is provided. The master cylinder 5 and the wheel cylinder 4 are each connected to a hydraulic unit 10. Then, the brake hydraulic pressure generated in the master cylinder 5 in accordance with the depression force of the brake pedal 6 (the driver's braking operation) is supplied to the wheel cylinder 4 after being controlled by the control unit 100 and the hydraulic pressure unit 10.

  A wheel speed sensor 91 that detects the wheel speed of each wheel 3 is connected to the control unit 100. The control unit 100 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an input / output circuit. The control is executed by performing various arithmetic processes based on the programs and data stored in. Details of the control unit 100 will be described later.

  As shown in FIG. 2, the hydraulic pressure unit 10 is disposed between the master cylinder 5 that generates brake hydraulic pressure corresponding to the pedaling force applied by the driver to the brake pedal 6 and the wheel brakes FR, FL, RR, RL. Has been.

  The hydraulic unit 10 is configured by arranging an oil passage and various electromagnetic valves in a pump body 11 which is a base body having an oil passage (hydraulic passage) through which brake fluid flows. The output ports 5a, 5b of the master cylinder 5 are connected to the input port 11a of the pump body 11, and the output port 11b of the pump body 11 is connected to each wheel brake FL, RR, RL, FR. In the normal state, the oil passage is communicated from the input port 11a to the output port 11b in the pump body 11, so that the depression force of the brake pedal 6 is transmitted to each wheel brake FL, RR, RL, FR. It is like that. The hydraulic system connected to the output port 5a of the master cylinder 5 is connected to the wheel brakes FL and RR, and the hydraulic system connected to the output port 5b of the master cylinder 5 is connected to the wheel brakes RL and FR. Each of these systems has substantially the same configuration.

  In each hydraulic pressure system, a pressure regulating valve 12 that is a normally open proportional solenoid valve capable of adjusting a difference in hydraulic pressure upstream and downstream in accordance with a supplied current on a hydraulic pressure path connecting the input port 11a and the output port 11b. Is provided. The pressure regulating valve 12 is provided with a check valve 12a that allows the flow only to the output port 11b side in parallel.

  The hydraulic pressure paths on the side of the wheel brakes FL, RR, RL, FR from the pressure regulating valve 12 are branched in the middle, and each is connected to the output port 11b. An inlet valve 13 that is a normally open proportional solenoid valve is disposed on each hydraulic pressure path corresponding to each output port 11b. Each inlet valve 13 is provided in parallel with a check valve 13a that allows a flow only to the pressure regulating valve 12 side.

  From the hydraulic pressure path between each output port 11b and the corresponding inlet valve 13, a reflux liquid connected between the pressure regulating valve 12 and the inlet valve 13 via an outlet valve 14 made of a normally closed electromagnetic valve, respectively. A pressure path 19B is provided.

  A reservoir 16, a check valve 16a, a pump 17, and an orifice 17a that temporarily absorb excess brake fluid are arranged on the reflux fluid pressure passage 19B in order from the outlet valve 14 side. The check valve 16 a is arranged so as to allow only the flow toward the space between the pressure regulating valve 12 and the inlet valve 13. The pump 17 is driven by a motor 21 and is provided so as to generate pressure between the pressure regulating valve 12 and the inlet valve 13. The orifice 17a attenuates the pulsation of the pressure of the brake fluid discharged from the pump 17 and the pulsation generated when the pressure regulating valve 12 operates.

  The inlet hydraulic pressure passage 19A connecting the input port 11a and the pressure regulating valve 12 and the portion between the check valve 16a and the pump 17 in the reflux hydraulic pressure passage 19B are connected by a suction hydraulic pressure passage 19C. A suction valve 15 that is a normally closed electromagnetic valve is disposed in the suction fluid pressure path 19C. Further, a pressure sensor 92 that detects the hydraulic pressure in the master cylinder 5 is provided in the introduction hydraulic pressure passage 19A.

  In the hydraulic pressure unit 10 configured as described above, the solenoid valves are not energized at normal times, and the brake hydraulic pressure introduced from the input port 11a passes through the pressure regulating valve 12 and the inlet valve 13 to the output port 11b. It is output and applied to each wheel cylinder 4 as it is. When the excessive brake fluid pressure in the wheel cylinder 4 is reduced, for example, when antilock brake control is performed, the corresponding inlet valve 13 is closed and the outlet valve 14 is opened to open the brake fluid through the reflux hydraulic pressure passage 19B. To the reservoir 16 and the brake fluid in the wheel cylinder 4 can be drained. Further, when the wheel cylinder 4 is pressurized when the driver does not operate the brake pedal 6, the intake valve 15 is opened and the motor 21 is driven, so that the wheel is positively driven by the pressure applied by the pump 17. Brake fluid can be supplied to the cylinder 4. Furthermore, when it is desired to adjust the degree of pressurization of the wheel cylinder 4, it can be adjusted by adjusting the current flowing through the pressure regulating valve 12.

Next, details of the control unit 100 will be described.
As shown in FIG. 3, the control unit 100 includes a wheel deceleration calculation unit 110, a wheel cylinder pressure estimation unit 120 as an example of a wheel cylinder pressure acquisition unit, a high μ road determination unit 130, and an antilock brake control unit. 140, a control execution unit 150, and a storage unit 160.

  The wheel deceleration calculation means 110 has a function of calculating the wheel deceleration Aw of each wheel 3 based on the wheel speed Vw of each wheel 3 acquired from the wheel speed sensor 91. When the wheel deceleration calculating unit 110 calculates the wheel deceleration Aw of each wheel 3, the wheel deceleration calculating unit 110 outputs the calculated wheel deceleration Aw to the antilock brake control unit 140 and the high μ road determination unit 130.

  The wheel cylinder pressure estimating means 120 is based on the master cylinder pressure Pm acquired from the pressure sensor 92 and the control history of the inlet valve 13 and the outlet valve 14 and the like output from the antilock brake control means 140. The hydraulic pressure in each wheel cylinder 4 (hereinafter also referred to as “wheel cylinder pressure Pw”) is estimated. When the wheel cylinder pressure estimation means 120 estimates each wheel cylinder pressure Pw, the wheel cylinder pressure estimation means 120 outputs each estimated wheel cylinder pressure Pw to the high μ road determination means 130.

  The high μ road determination means 130 is based on the front wheel cylinder pressure Pw output from the wheel cylinder pressure estimation means 120 and the wheel deceleration Aw of each wheel 3 output from the wheel deceleration calculation means 110. Thus, it has a function of determining whether or not the road surface is a high μ road. Specifically, the high μ road determination means 130 determines that the wheel cylinder pressures Pw of the left and right front wheels are greater than or equal to the first threshold TH1, and the absolute values of the wheel decelerations Aw of the wheels 3 are all greater than or equal to the second threshold TH2. In some cases, it is determined that the road is a high μ road.

  The fact that each wheel cylinder pressure Pw of the left and right front wheels is equal to or higher than the first threshold value TH1 indicates that each wheel cylinder pressure Pw is not reduced by the intervention of ABS control, that is, the road surface is not a low μ road. This means that the road surface μ is a certain high value. Further, the fact that the absolute values of the wheel deceleration Aw of each wheel 3 are all equal to or greater than the second threshold value TH2 means that the ground road surface of each wheel 3 is the same high μ road.

  When the high μ road determination means 130 determines that the road is a high μ road, it outputs a high μ signal indicating that fact to the anti-lock brake control means 140. A non-high μ signal indicating this is output to the antilock brake control means 140.

  Whether or not the anti-lock brake control unit 140 executes ABS control based on the wheel speed Vw of each wheel 3 acquired from the wheel speed sensor 91 and each wheel deceleration Aw acquired from the wheel deceleration calculation unit 110. Is determined for each wheel 3, and if it is determined to be executed, an instruction for hydraulic pressure control during ABS control (an instruction to select one of pressure reduction control, holding control, and pressure increase control) is determined for each wheel 3. It has a function. Specifically, the anti-lock brake control means 140 determines the speed of each wheel 3 based on the wheel speed Vw of each wheel 3 detected by the wheel speed sensor 91 and the vehicle speed Vc estimated based on each wheel speed Vw. A slip amount SL is calculated.

  In the present embodiment, a value obtained by subtracting the wheel speed Vw from the vehicle speed Vc is used as the slip amount SL. However, the present invention is not limited to this, and is represented by (Vc−Vw) / Vc. The slip ratio may be used as the slip amount SL.

  The anti-lock brake control means 140 determines that the wheel 3 is about to be locked when the slip amount SL is equal to or greater than a predetermined pressure-reduction threshold SLth and the wheel deceleration Aw is 0 or less. Is determined to be decompression control. Here, the wheel deceleration Aw has the same meaning as the wheel acceleration. When the wheel deceleration Aw is a negative value, the wheel 3 is decelerating. When the wheel deceleration Aw is a positive value, the wheel 3 is accelerated. Indicates that

  Further, when the wheel deceleration Aw is larger than 0, the antilock brake control means 140 determines the hydraulic pressure control instruction to be the holding control. Furthermore, the antilock brake control means 140 determines the hydraulic pressure control instruction to be the pressure increase control when the slip amount SL is less than the pressure reduction threshold SLth and the wheel deceleration Aw is 0 or less.

  Then, when the anti-lock brake control unit 140 determines the hydraulic pressure control instruction, the anti-lock brake control unit 140 outputs the determined hydraulic pressure control instruction (reduced pressure, hold, or increased pressure instruction) to the control execution unit 150.

  The antilock brake control unit 140 includes a threshold setting unit 141 for setting the above-described threshold and a basic pressure reduction amount setting unit 142 for setting the basic pressure reduction amount Pb in the pressure reduction control. Here, the pressure reduction control in the present embodiment is configured by basic pressure reduction control and gradual pressure reduction control. In the basic pressure reduction control, the hydraulic pressure is continuously reduced by the basic pressure reduction amount Pb, and in the gradual pressure reduction control, the pressure reduction control is minute. The liquid pressure is gradually reduced by repeatedly performing pressure reduction and minute holding.

  The threshold value setting means 141 is a function for setting the above-described pressure reduction threshold value SLth (intervention threshold value for pressure reduction control in ABS control) based on the signal output from the high μ road determination means 130 before the ABS control is started. have. Specifically, when the signal output from the high μ road determination unit 130 is a non-high μ signal, the threshold setting unit 141 sets the decompression threshold SLth to the first decompression threshold SLth1. Here, the first pressure reduction threshold value SLth1 is a threshold value set in a situation where the road surface μ is not known, and is set to a value that is small to some extent in consideration of the low μ road by experiments, simulations, and the like.

  Further, when the signal output from the high μ road determination unit 130 is a high μ signal, the threshold setting unit 141 sets the decompression threshold SLth to a second decompression threshold SLth2 that is larger than the first decompression threshold SLth1. . The pressure reduction threshold SLth set before the start of the ABS control only needs to be held until at least the second pressure increase control is started. For example, after the second pressure increase control is started, the conventional method ( It may be reset based on the road surface μ estimated by the method using the wheel speed at the start of pressure increase.

  The basic pressure reduction amount setting unit 142 sets the above-described basic pressure reduction amount Pb (the pressure reduction amount of the pressure reduction control in the ABS control) based on the signal output from the high μ road determination unit 130 before the ABS control is started. It has a function to set. Specifically, the basic pressure reduction amount setting unit 142 sets the basic pressure reduction amount Pb to the first pressure reduction amount Pb1 when the signal output from the high μ road determination unit 130 is a non-high μ signal. Here, the first depressurization amount Pb1 is a threshold value set in a situation where the road surface μ is not known, and is set to a certain large value in consideration of the low μ road by experiments and simulations.

  In addition, when the signal output from the high μ road determination unit 130 is a high μ signal, the basic decompression amount setting unit 142 sets the basic decompression amount Pb to a second decompression amount Pb2 that is smaller than the first decompression amount Pb1. Set to. Note that the basic pressure reduction amount Pb set before the start of the ABS control only needs to be held at least until the second pressure increase control is started. For example, after the start of the second pressure increase control, the conventional method It may be reset based on the road surface μ estimated by.

  The control execution means 150 has a function of controlling the wheel cylinder pressure Pw by controlling the inlet valve 13 and the outlet valve 14 based on the hydraulic pressure control instruction output from the antilock brake control means 140. doing. Specifically, when the instruction of the hydraulic pressure control is the pressure reduction control, the control execution unit 150 closes the inlet valve 13 and opens the outlet valve 14 by causing a current to flow through the inlet valve 13 and the outlet valve 14. To control. In addition, when the hydraulic pressure control instruction is holding control, the control execution unit 150 causes both the inlet valve 13 and the outlet valve 14 to flow by supplying current to the inlet valve 13 and not flowing current to the outlet valve 14. Both are controlled to close.

  The control execution means 150 closes the outlet valve 14 by not flowing current to the outlet valve 14 and does not flow current to the inlet valve 13 when the instruction of hydraulic pressure control is pressure increase control, or By flowing a drive current corresponding to the indicated hydraulic pressure, the pressure difference between the upstream and downstream of the inlet valve 13 is controlled, and the wheel cylinder pressure Pw is increased at the intended pressure increase rate.

  The storage means 160 stores the above-described threshold values TH1, TH2, SLth1, SLth2, and the reduced pressure amounts Pb1, Pb2.

Next, a method for setting the decompression threshold SLth and the basic decompression amount Pb for the ABS control by the control unit 100 will be described with reference to FIG.
As shown in FIG. 4, when the brake pedal 6 is depressed by the driver (START), the control unit 100 first determines whether or not ABS control is being performed (S1). If it is determined in step S1 that the ABS control is being performed (Yes), the control unit 100 ends this control.

  If it is determined in step S1 that the ABS control is not being performed (No), the control unit 100 acquires the wheel speed Vw and the master cylinder pressure Pm of each wheel 3 from the sensors 91 and 92 (S2). After step S2, the control unit 100 calculates the wheel deceleration Aw of each wheel 3 from the wheel speed Vw of each wheel 3 (S3).

  After step S3, the control unit 100 estimates each wheel cylinder pressure Pw of the left and right front wheels from the master cylinder pressure Pm and the control history of the ABS control (S4). Since there is no control history before starting the ABS control, the control unit 100 estimates the value of the master cylinder pressure Pm as it is as the wheel cylinder pressure Pw of the left and right front wheels.

  After step S4, the control unit 100 determines whether or not each wheel cylinder pressure Pw is greater than or equal to the first threshold value TH1 (S5). If it is determined in step S5 that the wheel cylinder pressures Pw are both equal to or greater than the first threshold value TH1 (Yes), the control unit 100 determines that the absolute values of the wheel decelerations Aw of the wheels 3 are all equal to or greater than the second threshold value TH2. It is determined whether or not (S6).

  When it is determined in step S5 that at least one of the left and right wheel cylinder pressures Pw is less than the first threshold TH1 (No), or in step S6, the wheel deceleration Aw of at least one of the wheels 3 is determined. When it is determined that the absolute value is less than the second threshold value TH2 (No), the control unit 100 determines that the road is not a high μ road, and proceeds to the process of step S7.

  In step S7, the control unit 100 sets the first depressurization threshold SLth1 as the depressurization threshold SLth (S7). After step S7, the control unit 100 sets the first pressure reduction amount Pb1 as the basic pressure reduction amount Pb (S8), and ends this control.

  If it is determined in step S6 that the absolute values of the wheel deceleration Aw of each wheel 3 are all equal to or greater than the second threshold value TH2 (Yes), the control unit 100 determines that the road is a high μ road, and the decompression threshold value SLth. As a result, a second decompression threshold SLth2 larger than the first decompression threshold SLth1 is set (S9). After step S9, the control unit 100 sets the second pressure reduction amount Pb2 smaller than the first pressure reduction amount Pb1 as the basic pressure reduction amount Pb (S10), and ends this control.

  Next, an example of control by the control unit 100 will be described with reference to FIG. In addition, the waveform of the wheel deceleration Aw shown in FIG.5 (b) has shown the value which added this time value to the last value of wheel deceleration Aw.

  As shown in FIGS. 5A and 5C, when the driver steps on the brake pedal 6 (time t1), the master cylinder pressure Pm and the wheel cylinder pressures Pw of the front wheels (only one is shown) increase. As the vehicle speed increases, the vehicle speed Vc and the wheel speed Vw decrease. In the initial stage of the brake control, the pressure reduction threshold SLth is set to the first pressure reduction threshold SLth1, and the basic pressure reduction amount Pb is set to the first pressure reduction amount Pb1.

  Thereafter, as shown in FIGS. 5B and 5C, the absolute value of the wheel deceleration Aw (only one is shown) of each wheel 3 becomes equal to or greater than the second threshold value TH2 (time t2), and each wheel cylinder When both the pressures Pw are equal to or higher than the first threshold value TH1 (time t3), the control unit 100 determines that the road is a high μ road. Here, in FIG. 5B, for convenience, the second threshold value TH2 is also shown as a negative value in accordance with the negative wheel deceleration Aw, but this is the absolute value of the wheel deceleration Aw and the positive second value. This is synonymous with the comparison with the threshold value TH2.

  When determining that the road is a high μ road, the control unit 100 resets the decompression threshold SLth from the first decompression threshold SLth1 to the second decompression threshold SLth2 that is larger than the first decompression threshold SLth1, and sets the basic decompression amount Pb to the first decompression threshold Pth. The first pressure reduction amount Pb1 is reset to the second pressure reduction amount Pb2 smaller than the first pressure reduction amount Pb1. Accordingly, the start timing of the pressure reduction control on the high μ road is changed from time t4 (time when the slip amount SL becomes equal to or higher than the first pressure reduction threshold SLth1) to time t5 (time when the slip amount SL becomes equal to or higher than the second pressure reduction threshold SLth2). The wheel cylinder pressure Pw can be suppressed from being excessively reduced.

  Here, in the graphs indicated by broken lines in FIGS. 5A and 5C, the high-μ road determination is not performed, and the depressurization threshold SLth and the basic depressurization amount Pb are set to the first depressurization threshold SLth1 and the first depressurization threshold SLth1. A mode in which the reduced pressure Pb1 is set as it is is shown. In this embodiment, since the pressure reduction threshold SLth is the first pressure reduction threshold SLth1 smaller than the second pressure reduction threshold SLth2, the pressure reduction control is started at an earlier timing (time t4) than in the present embodiment. Further, in this embodiment, since the basic pressure reduction amount Pb is the first pressure reduction amount Pb1 larger than the second pressure reduction amount Pb2, the wheel cylinder pressure Pw is reduced more greatly than in the present embodiment.

According to the above, the following effects can be obtained in the present embodiment.
Since it is determined whether or not the road is a high μ road based on each wheel cylinder pressure Pw of the front wheel and the wheel deceleration Aw of each wheel 3, the road surface μ can be determined at the start of the ABS control pressure reduction control. .

  When each wheel cylinder pressure Pw of the left and right front wheels is greater than or equal to the first threshold TH1 and the absolute values of the wheel deceleration Aw of each wheel 3 are all greater than or equal to the second threshold TH2, it is determined that the road is a high μ road. Therefore, the road surface μ can be determined with high accuracy.

  If it is determined that the road is a high μ road, the pressure reduction threshold SLth of the pressure reduction control in the ABS control is set to a large second pressure reduction threshold SLth2, and therefore the timing at which the ABS control is started on the high μ road may be delayed. it can.

  When it is determined that the road is a high μ road, the basic pressure reduction amount Pb of the pressure reduction control in the ABS control is set to a small second pressure reduction amount Pb2, so that excessive pressure reduction on the high μ road can be suppressed. it can.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, the wheel cylinder pressure estimation unit 120 that estimates the wheel cylinder pressure Pw from the master cylinder pressure Pm and the control history is exemplified as the wheel cylinder pressure acquisition unit, but the present invention is not limited to this. For example, a means for acquiring the wheel cylinder pressure from a sensor that detects the wheel cylinder pressure may be used.

  In the above embodiment, the wheel cylinder pressures Pw of the left and right front wheels are compared with the first threshold value TH1, but the present invention is not limited to this, and only the wheel cylinder pressures of the left and right front wheels are compared with the first threshold value. May be. However, when the wheel cylinder pressures Pw of the left and right front wheels are compared with the first threshold value TH1 as in the above-described embodiment, it is difficult to determine a high μ road on a split road where the left and right road surfaces μ are greatly different. Good braking control can be performed at

DESCRIPTION OF SYMBOLS 1 Brake hydraulic pressure control apparatus for vehicles 3 Wheel 100 Control part 110 Wheel deceleration calculation means 120 Wheel cylinder pressure estimation means 130 High micro road determination means

Claims (4)

Wheel deceleration calculating means for calculating the wheel deceleration of each wheel;
Wheel cylinder pressure acquisition means for acquiring the wheel cylinder pressure of the front wheel;
Based on the wheel cylinder pressure of the front wheel acquired by the wheel cylinder pressure acquisition means and the wheel deceleration of each wheel calculated by the wheel deceleration calculation means, it is determined whether or not the road surface is a high μ road. A vehicle brake fluid pressure control device comprising: a high μ road determination unit.   The high μ road determination means is a high μ road when the wheel cylinder pressures of the left and right front wheels are equal to or higher than the first threshold value and the wheel deceleration absolute values of the wheels are all equal to or higher than the second threshold value. The vehicular brake hydraulic pressure control device according to claim 1, wherein the vehicular brake hydraulic pressure control device is determined to be present.   Threshold setting means for setting an intervention threshold value for pressure reduction control in anti-lock brake control to a larger value than when it is determined not to be a high μ road when the high μ road determination means determines that the road is a high μ road The vehicular brake hydraulic pressure control device according to claim 1 or 2, further comprising:   When it is determined by the high μ road determination means that the road is a high μ road, the pressure reduction amount of the pressure reduction control in the antilock brake control is set to a value smaller than that when it is determined that the road is not a high μ road. The vehicular brake hydraulic pressure control device according to any one of claims 1 to 3.

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