JP6473647B2 - Brake hydraulic pressure control device for vehicles - Google Patents

Description

  The present invention relates to a vehicular brake hydraulic pressure control device that controls a brake hydraulic pressure of a wheel brake that applies a braking force to a wheel, and relates to a vehicle brake hydraulic pressure control device that is suitable for application to a vehicle such as a two-wheeled vehicle or a four-wheeled vehicle. .

  For example, Patent Document 1 discloses a vehicle brake fluid pressure control apparatus capable of controlling brake fluid pressure, such as anti-lock brake control (ABS control) that suppresses wheel lock, in order to accurately control the brake fluid pressure. In addition, there is disclosed a configuration in which a normally open proportional solenoid valve capable of freely changing the valve opening amount is employed as an inlet valve communicating with the master cylinder.

  In the vehicle brake hydraulic pressure control device disclosed in Patent Document 1, the difference in brake hydraulic pressure between the upstream side and the downstream side of the inlet valve is determined according to the magnitude of the drive current that flows through the electromagnetic coil of the inlet valve. Is adjusted.

  Patent Document 2 discloses a vehicle brake hydraulic pressure control device having a configuration in which a regulator is provided between the master cylinder and the inlet valve.

JP 2009-23468 A JP 2007-76528 A

  By the way, in the technique disclosed in Patent Document 1, the valve opening amount of the normally open proportional solenoid valve is set, and the difference between the brake fluid pressure in the upstream fluid passage and the brake fluid pressure in the downstream fluid passage of the inlet valve is set. When adjusting the pressure, the difference between the brake fluid pressure in the upstream fluid passage (master cylinder pressure) detected by the pressure sensor and the estimated brake fluid pressure in the downstream fluid passage (brake fluid pressure in the wheel brake) is detected. The pressure is calculated ([0033] of Patent Document 1).

  However, since the pressure sensor is a relatively expensive and large component as a circuit component, there is a problem that this is an obstacle to downsizing and cost reduction of the entire vehicle brake hydraulic pressure control device.

  The present invention has been made in consideration of such a problem, and it is possible to accurately estimate the brake fluid pressure in the upstream fluid passage of the control valve unit without using a pressure sensor. An object is to provide a pressure control device.

  A brake fluid pressure control device for a vehicle according to the present invention is provided in a brake fluid fluid path from a fluid pressure source that generates brake fluid pressure by operation of an operator to a wheel brake, and acts on the wheel brake. A control valve unit that switches to a state of reducing, increasing, or holding the pressure, a reservoir that stores the brake fluid released from the wheel brake through the control valve unit during the pressure reduction, a motor, and a motor driven by the motor A brake fluid pressure control device for a vehicle, comprising a pump that sucks the brake fluid from the reservoir side and discharges the brake fluid to an upstream fluid passage of the control valve unit, from the start of the fluid pressure control Rotating the motor, obtaining an increase amount of the motor load at the time of pressure reduction immediately after the start of the hydraulic pressure control, based on the obtained increase amount of the motor load, Estimating the brake fluid pressure of the fluid side fluid passage.

  The higher the brake fluid pressure (upstream brake fluid pressure) in the upstream fluid passage of the control valve unit, which is the pump brake fluid discharge side, the greater the load on the motor when the pump is switched from the stopped state to the activated state. The motor load increases. According to this invention, even if no pressure sensor is provided, the brake of the upstream side fluid passage of the control valve unit is based on the increase amount of the motor load (motor load) rotated before the start of the fluid pressure control. The hydraulic pressure can be estimated with high accuracy. As a result, it is possible to reduce costs such as pressure sensor component costs, management costs, and assembly costs. Moreover, since the estimation is based on the motor load immediately after the start of the hydraulic pressure control, the brake hydraulic pressure in the upstream side fluid passage of the control valve unit can be estimated early immediately after the start of the hydraulic pressure control. Based on the brake fluid pressure in the upstream fluid passage, fluid pressure control can be performed with high accuracy.

  In addition, when estimating the brake fluid pressure of the upstream fluid passage, the upstream fluid passage is preliminarily associated with the characteristic of the brake fluid pressure of the upstream fluid passage with respect to the increase amount of the motor load. The brake fluid pressure may be estimated.

  The increase in the motor load is estimated by estimating the brake fluid pressure in the upstream fluid passage using the characteristic of the brake fluid pressure in the upstream fluid passage with respect to the increase amount of the motor load that is associated in advance. The upstream brake fluid pressure can be easily estimated from the amount. The characteristics can be obtained in advance by experiments, simulations, or the like.

  More specifically, the increase amount of the motor load at the time of depressurization immediately after the start of the hydraulic pressure control, the amount of decrease in the rotation speed of the motor at the time of depressurization immediately after the start of the hydraulic pressure control, or the motor voltage You may make it obtain | require from the amount of depressions.

  In this case, using the characteristic of the brake fluid pressure of the upstream fluid passage with respect to the amount of temporary drop in the rotation speed of the motor at the time of pressure reduction immediately after the start of the fluid pressure control, which is associated in advance, Estimating the brake fluid pressure in the upstream fluid passage, or using the characteristics of the brake fluid pressure in the upstream fluid passage with respect to the amount of decrease in the motor voltage during pressure reduction immediately after the start of the fluid pressure control, By estimating the brake fluid pressure in the fluid passage, the brake fluid pressure in the upstream fluid passage of the control valve unit communicating with the fluid pressure source can be easily estimated. Also in this case, the characteristics can be obtained in advance by experiments, simulations, or the like.

  According to the present invention, the higher the brake fluid pressure (upstream brake fluid pressure) in the upstream fluid passage that is the discharge side of the brake fluid of the pump, the higher the load on the motor when the pump is switched from the stopped state to the activated state. By considering that the motor load increases, even if no pressure sensor is provided, the control is based on the increase amount of the motor load (motor load) rotated before the start of hydraulic pressure control. The effect is achieved that the brake fluid pressure in the upstream fluid passage of the valve unit can be accurately estimated.

1 is a schematic configuration diagram of a vehicle brake hydraulic pressure control device according to an embodiment. It is a flowchart with which the estimation process of a master cylinder pressure is performed by the brake fluid pressure control apparatus for vehicles. It is a characteristic view which shows the correspondence of the master cylinder pressure with respect to the rotation amount fall amount or the increase amount of a back electromotive force. It is a time chart used for operation | movement description of the estimation process of a master cylinder pressure. 5 is a time chart schematically showing, on the time axis, a change in the motor rotation speed from before the ABS operation is started to immediately after the start of the operation in the time chart of FIG. 4.

  Hereinafter, preferred embodiments of a vehicle brake hydraulic pressure control device according to the present invention will be described in detail with reference to the accompanying drawings.

  A vehicle brake fluid pressure control device is mounted on a vehicle and suppresses wheel slip while changing the distribution of brake fluid pressure to each wheel in accordance with the behavior of the vehicle, road surface conditions, brake operation conditions, and the like. It executes ABS control with EBD (Electronic Break Force Distribution) control, skid control for stabilizing the behavior of the vehicle, traction control (hereinafter referred to as behavior stabilization control), and the like.

  FIG. 1 shows a schematic configuration of a vehicle brake hydraulic pressure control device 10 according to this embodiment.

  In FIG. 1, four wheel brakes (wheel brake FR on the right side of the front wheel, wheel brake RL on the left side of the rear wheel, wheel brake FL on the left side of the front wheel, and right side of the rear wheel are shown for convenience of understanding and for convenience. The brake system K1 for applying braking force to the two wheel brakes FR and RL is shown. The brake system K2 that applies braking force to the remaining two wheel brakes FL and RR (not shown) is substantially the same in configuration and is not shown. Hereinafter, the brake system K1 will be mainly described. K2 will be described as appropriate.

  As shown in FIG. 1, the vehicular brake hydraulic pressure control device 10 basically has a master cylinder 12 as a hydraulic pressure source, brake systems K1, K2, and a control unit that controls the brake systems K1, K2. ECU (Electronic Control Unit) 16.

  The master cylinder 12 has a pedaling force applied to the brake pedal 20 (operator) in each upstream liquid passage 104, 103 communicating with each output port 24a, 24b provided corresponding to the two brake systems K1, K2. A brake fluid pressure (referred to as a master cylinder pressure) Pmc corresponding to In practice, the pedaling force applied to the brake pedal 20 is increased in pressure via the booster 22 and is applied to the master cylinder 12. The output ports 24a and 24b of the master cylinder 12 are connected to the actuator 14 via piping.

  The brake system K1 includes an actuator 14 and wheel brakes FR and RL. Each wheel brake FR, RL is connected to the actuator 14 via a pipe.

  The actuator 14 basically includes an upstream fluid passage 104 communicated with the master cylinder 12, wheel brake fluid passages (also referred to as wheel cylinder fluid passages) 106a and 106b communicated with the wheel brakes FR and RL, and brake fluid passages. The control valve unit 30 provided between the escape liquid passage 108, the reservoir 34 communicating with the escape liquid passage 108, the pump 70 provided between the suction liquid passage 110 and the discharge liquid passage 118 of the pump 70, And a motor 72 for driving the pump 70. The discharge liquid path 118 of the pump 70 communicates with the upstream liquid path 104 of the control valve unit 30.

  Wheel brake fluid passages 106a and 106b, which are downstream fluid passages of the control valve unit 30, communicate with wheel cylinders 18a and 18b constituting the wheel brakes FR and RL, respectively. The wheel brake FR is composed of a wheel cylinder 18a and a brake member such as a brake disk, and the wheel brake RL is composed of a wheel cylinder 18b and a brake member such as a brake disk.

  A relief fluid passage 108 for allowing the brake fluid to escape from the wheel brake fluid passages 106 a and 106 b through the control valve unit 30 communicates with the reservoir 34 via the suction fluid passage 110.

  The control valve unit 30 includes inlet valves 51 and 61 that are normally open proportional solenoid valves, outlet valves 52 and 62 that are normally closed solenoid valves, and check valves 53 and 63. In the inlet valves 51 and 61, the valve opening amount can be freely adjusted by the energization amount to the electromagnetic coil from the ECU 16. As known, the inlet valve 51, the outlet valve 52, and the check valve 53, and the inlet valve 61, the outlet valve 62, and the check valve 63 may be replaced with one three-position solenoid valve. .

  The control valve unit 30 is provided at the intersection of the upstream fluid passage 104, the wheel brake fluid passages 106a and 106b, and the escape fluid passage 108, and the upstream fluid passage 104 and the wheel brake fluid passages 106a and 106b. Pressure increase state in which the relief fluid passage 108 is shut off by communicating (opening), the decompression state in which the upstream fluid passage 104 and the wheel brake fluid passages 106a and 106b are shut off and the escape fluid passage 108 is communicated (opened), and the wheel The brake fluid passages 106 a and 106 b have a function of switching a holding state in which the brake fluid passages 106 a and 106 b are blocked from the upstream fluid passage 104 and the escape fluid passage 108. In other words, the control valve unit 30 increases the brake fluid pressure of the wheel brake fluid passages 106a and 106b acting on the wheel cylinders 18a and 18b, in other words, the state in which the wheel cylinder pressures Pwca and Pwcb are increased, the state in which the pressure is reduced, and the state in which the pressure is maintained. Switch. In the following description, the wheel cylinder pressures Pwca and Pwcb are representatively referred to as wheel cylinder pressures Pwc, unless they need to be described separately.

  The check valves 53 and 63 are provided in parallel to the inlet valves 51 and 61, respectively, and allow only the inflow of the brake fluid from the wheel brake fluid passages 106a and 106b to the upstream fluid passage 104.

  The inlet valves 51 and 61 are provided between the upstream side fluid passage 104 and the wheel brake fluid passages 106a and 106b, respectively. When the inlet valves 51 and 61 are open at the normal time when the fluid pressure control is not performed (normally open), The brake fluid pressure is allowed to be transmitted from the cylinder 12 to the wheel brakes FR and RL.

  On the other hand, the inlet valves 51 and 61 are closed when the wheel is about to be locked during the hydraulic pressure control, thereby blocking the brake hydraulic pressure transmitted from the brake pedal 20 to the wheel brakes FR and RL. To do. Further, during the hydraulic pressure control, the inlet valves 51 and 61 are controlled by the ECU 16 so as to have a predetermined valve opening amount, thereby increasing the brake hydraulic pressure in each wheel brake FR and RL with a predetermined inclination. Let

  The outlet valves 52 and 62 are provided between the wheel brake fluid passages 106a and 106b and the escape fluid passage 108, respectively. When the valve is in a closed state, the outlet valves 52 and 62 supply brake fluid from the wheel cylinders 18a and 18b to the reservoir 34. Block inflow and allow when valve is open.

  The reservoir 34 is provided in the suction fluid passage 110 and passes through the escape fluid passage 108 and the suction fluid passage 110 from the wheel cylinders 18 a and 18 b and the wheel brake fluid passages 106 a and 106 b through the outlet valves 52 and 62 of the control valve unit 30. It has a function of temporarily storing the released brake fluid.

  The pump 70 is provided between the suction liquid path 110 and the discharge liquid path 118, is driven by the rotational force of the motor 72, and sucks the brake fluid temporarily stored in the reservoir 34 through the suction liquid path 110 to generate a pressure. Is discharged to the discharge liquid passage 118. Thus, the brake fluid stored in the reservoir 34 is returned to the discharge fluid passage 118 communicated with the upstream fluid passage 104, whereby the brake fluid is returned to the master cylinder 12 side.

  The ECU 16 is a CPU (central processing unit), a ROM (including EEPROM) as a memory, a RAM (random access memory), and other input / output devices such as an A / D converter, a D / A converter, and a drive circuit. And a timer or the like as a time measuring unit, and the CPU reads and executes a program recorded in the ROM based on an input signal or the like, so that various function realizing units (function realizing means), for example, a control unit, an arithmetic unit, etc. And function as a processing unit or the like. These functions can also be realized by hardware. In that case, the term “˜unit” in the “function realization unit” is replaced with “˜circuit”, “˜device”, or “˜device”.

  More specifically, the ECU 16 according to this embodiment sets the current value related to the energization amount that excites the electromagnetic coils that drive the valve bodies of the inlet valves 51 and 61 that are normally open proportional solenoid valves from 0 to the maximum value. Or, it is adjusted to near the maximum value, adjusted to a predetermined amount of valve opening (predetermined opening amount) between the fully opened state of the valve with the maximum valve opening amount and the valve closed state, and opened by demagnetizing. Set the valve to the fully open state. Further, the solenoid coil that drives the valve bodies of the outlet valves 52 and 62 that are normally closed solenoid valves is energized to be opened, and demagnetized to be closed.

  The motor 72 is a common power source for the pumps 70 in the brake systems K1 and K2, and operates based on a motor drive signal Sd from the ECU 16. In this case, the ECU 16 takes in the terminal voltage (motor voltage) Vm of the motor 72 generated according to the drive signal Sd as a voltage signal.

  The ECU 16 also rotates a wheel rotation speed (wheel speed) Nw from a wheel speed sensor 19 provided on each of four wheels (not shown), and a rotation speed (motor rotation) from a rotation speed sensor (not shown) of the motor 72. Number) Each detection signal such as Nm, a motor current Im from a current sensor (not shown) of the motor 72, and the motor voltage Vm from a voltage sensor (not shown) of the motor 72 is fetched.

  Further, the ECU 16 takes in each detection signal from a brake pedal operation amount (brake pedal stroke amount) detected by a stroke sensor 21 provided at a fulcrum of the brake pedal 20 and a pedal operation switch (not shown).

  The ECU 16 estimates the master cylinder pressure Pmc based on each captured detection signal, and controls the control valve unit 30 (electromagnetic valves including the inlet valves 51 and 61 and the outlet valves 52 and 62), the motor 72, and the like. To do.

  In FIG. 1, in order to avoid complication, wiring between the ECU 16 and each electromagnetic valve, between the ECU 16 and the motor 72, and between the ECU 16 and various sensors is omitted.

  The operation of the vehicular brake hydraulic pressure control apparatus 10 according to this embodiment basically configured as described above will be described next in the order of [basic operation] and [master cylinder pressure estimation processing]. .

[Basic operation]
The basic operation of the vehicular brake hydraulic pressure control device 10 is the same as that of this kind of well-known and well-known brake control device.

  For example, when the brake pedal 20 is operated to apply a brake, a detection signal corresponding to the operation is input to the ECU 16 by a pedal operation switch (not shown).

  At this time, brake fluid having a hydraulic pressure corresponding to the operation of the brake pedal 20 is supplied from the master cylinder 12 to the wheel cylinders 18a and 18b through the control valve unit 30, and braking force is applied to the wheel brakes FR and RL. In this case, the master cylinder pressure Pmc and the wheel cylinder pressure Pwc are the same pressure because the upstream side fluid passage 104 and the fluid passage of the wheel brake fluid passage 106a (106b) communicate with each other.

  When the ECU 16 determines that the hydraulic pressure control such as the ABS control is necessary, for example, if the ECU 16 determines that the brake hydraulic pressure should be reduced, the outlet valves 52 and 62 are excited by the ECU 16 to be in the open state. Fluid pressure control is started by exciting the inlet valves 51 and 61 and closing them instantaneously. As a result, the brake fluid in the wheel cylinders 18a, 18b is discharged to the reservoir 34 through the relief fluid passage 108 and the suction fluid passage 110 through the outlet valves 52, 62, and the brake fluid pressure in the wheel brake fluid passages 106a, 106b, that is, the wheel cylinder. The pressure Pwc is reduced.

  The ECU 16 excites the outlet valves 52, 62 and simultaneously drives the motor 72, whereby the brake fluid stored in the reservoir 34 is sucked in through the suction liquid passage 110 by the pump 70, and upstream through the discharge liquid passage 118. The liquid is recirculated to the side liquid passage 104, in other words, to the master cylinder 12 side.

  When the ECU 16 determines that the brake fluid pressure should be maintained, the outlet valves 52 and 62 are demagnetized and closed. As a result, the wheel brake fluid passages 106a and 106b are disconnected from the upstream fluid passage 104 and the escape fluid passage 108, and the wheel cylinder pressure Pwc is kept constant.

  When the ECU 16 determines that the brake fluid pressure should be increased, the outlet valves 52 and 62 are demagnetized and closed, and the inlet valves 51 and 61 are gradually lowered from a higher current value to be lower. As a result, the wheel cylinder pressure Pwc is gradually increased.

  Hereinafter, until it is determined that fluid pressure control such as ABS control is unnecessary, such fluid pressure control of pressure reduction, holding, and pressure increase is appropriately selected and executed.

[Master cylinder pressure estimation processing]
During hydraulic pressure control by the ECU 16 such as ABS control, the master cylinder pressure Pmc is used as a control parameter for the ECU 16.

  Then, next, the estimation process of the master cylinder pressure Pmc which is the brake fluid pressure (upstream brake fluid pressure) of the upstream fluid passage 104 of the control valve unit 30 by the vehicle brake fluid pressure control device 10 is shown in FIG. This will be described with reference to a flowchart. The execution subject of the program according to the flowchart described below is the ECU 16 (or its CPU).

  In step S1, the ECU 16 determines whether or not there is an operation sign of hydraulic pressure control such as ABS control. This determination is affirmative (step S1: YES) when, for example, a predetermined control parameter (such as the slip ratio of the vehicle in the case of ABS control) becomes a value approaching the start threshold value of the hydraulic pressure control. Is done. In addition, it is good also as affirmation at the time of the start of EBD control.

  When an operation sign of hydraulic pressure control such as ABS control is not detected (step S1: NO), the process is terminated.

  If it is determined that there is a hydraulic pressure control indication (step S1: YES), the ECU 16 outputs to the motor 72 a motor drive signal Sd for rotating the motor 72 at the target rotational speed Nmtar in step S2. .

  In this embodiment, the motor drive signal Sd is a repetitive square wave that is switched between a low level (off) and a high level (on), and is a PWM signal having a constant voltage and a constant period {PWM (pulse width modulation) period}. ing. Therefore, in practice, in this step S2, the ECU 16 starts supplying the motor drive signal Sd set to the motor 72 with the duty ratio D (D = on period / PWM cycle) corresponding to the target rotational speed Nmtar.

  In this embodiment, the motor 72 is a DC motor that increases the motor rotation speed Nm by increasing the duty ratio D of the motor drive signal Sd.

  In step S2, the target rotational speed Nmtar or the target bottom voltage Vtar of the motor voltage Vm corresponding to the target rotational speed Nmtar is stored in the storage unit.

  Next, the ECU 16 determines whether or not hydraulic pressure control is started in step S3.

  For example, the start of ABS control is affirmed when the slip ratio of the vehicle exceeds a predetermined value and a sudden deceleration of the wheel speed Nw from the wheel speed sensor 19 (possibility of locking of the wheel brakes FR and RL) is detected. (Step S3: YES).

  When it is determined that the hydraulic pressure control is started, the ECU 16 calculates a motor load (an increase amount of the motor load) in step S4.

  When the hydraulic pressure control is started and the brake fluid is released from the wheel brake fluid passages 106a and 106b to the reservoir 34 through the outlet valve 52 and the escape fluid passage 108, the brake fluid is sucked into the pump 70 from the reservoir 34 side through the suction fluid passage 110. The pump 70 is suddenly loaded. Therefore, the motor 72 that drives the pump 70 changes from the idling state to a state in which a load is applied, and the rotational speed Nm of the motor 72 temporarily falls from the target rotational speed Nmtar.

  Since the temporary drop amount (motor rotation speed drop amount) ΔNm of the motor rotation speed Nm from the target rotation speed Nmtar is correlated with the motor load, the motor rotation speed drop amount ΔNm is detected and the motor rotation speed drop is detected. The amount ΔNm can be calculated as a motor load (amount of increase in motor load). In step S4, the motor rotational speed drop amount ΔNm calculated by the ECU 16 is stored in the storage unit.

  Instead of calculating and storing the motor rotation speed drop amount ΔNm as a motor load (a motor load increase amount), the target bottom voltage Vtar of the motor voltage Vm is temporarily correlated with the motor rotation speed drop amount ΔNm. It is also possible to detect a small drop amount (bottom voltage drop amount) ΔVi, calculate the bottom voltage drop amount ΔVi as a motor load (an increase amount of the motor load), and store it in the storage unit.

  Next, in step S5, the ECU 16 performs a process of estimating the master cylinder pressure Pmc based on the motor rotation speed drop amount ΔNm or the bottom voltage drop amount ΔVi detected and stored in step S6.

  FIG. 3 shows a characteristic 202 indicating a correspondence relationship between the motor rotational speed drop amount ΔNm [rpm] and the master cylinder pressure Pmc [MPa] acquired in advance through experiments or simulations. The master cylinder pressure Pmc changes substantially linearly with respect to the motor rotational speed drop amount ΔNm detected by the ECU 16.

  Therefore, the master cylinder pressure Pmc can be estimated (step S5) by referring to the characteristic 202 by detecting and taking in the motor rotational speed drop amount ΔNm (step S4). Note that the characteristic 202 may be stored in the storage unit as an arithmetic expression for use.

  The characteristic 202 in FIG. 3 shows the correspondence between the motor rotational speed drop amount ΔNm and the master cylinder pressure Pmc. Instead of this, the drop amount ΔVi [ V] and the master cylinder pressure Pmc [MPa] indicating the correspondence relationship (referred to as bottom voltage drop amount / master cylinder pressure characteristic) are stored in the storage unit, whereby the bottom voltage drop amount is determined in step S4. By detecting and taking in ΔVi, the master cylinder pressure Pmc can be estimated in step S5 with reference to the bottom voltage drop amount / master cylinder pressure characteristics. The bottom voltage drop amount / master cylinder pressure characteristic may also be stored in the storage unit as an arithmetic expression for use.

  Thus, the master cylinder pressure Pmc can be estimated by detecting the motor rotational speed drop amount ΔNm or the bottom voltage drop amount ΔVi (step S5).

  Next, in step S6, the master cylinder pressure Pmc estimated in step S5 is applied to hydraulic pressure control (described later).

[Specific operation example of master cylinder pressure estimation processing]
Here, a specific operation example of the process of estimating the master cylinder pressure Pmc that is the brake fluid pressure (referred to as upstream brake fluid pressure) in the upstream fluid passage 104 of the control valve unit 30 by the vehicle brake fluid pressure control device 10. Will be described with reference to the time chart of FIG.

  As shown in the time chart of FIG. 4, for example, at time t-1, the brake pedal 20 is operated and the master cylinder pressure Pmc gradually increases, and at time t0, the rear wheel brake RL is applied to the front wheel. If the EBD control that the wheel cylinder pressure Pwcb should be held prior to the wheel brake FR is activated, it is determined that there is an ABS operation activation sign (corresponding to step S1: YES).

  In this case, at time t0, the ECU 16 excites the inlet valve 61 communicating with the wheel brake RL of the rear wheel to close the valve instantaneously, and is maintained at the target wheel cylinder pressure Pwcb.

  At the same time, before the hydraulic pressure control such as ABS control is started at time t0, the duty ratio D (D = on) corresponding to the target rotational speed Nmtar is set so that the motor 72 starts to rotate and reaches the target rotational speed Nmtar. The supply of the motor drive signal Sd set to (period / PWM cycle) from the ECU 16 to the motor 72 is started and continued (corresponding to step S2).

  The time chart of FIG. 5 shows changes in the motor drive signal Sd, the motor voltage Vm, the bottom voltage Vi of the motor voltage Vm, and the motor rotation speed Nm between the time t0 and the time t4 in the time chart of FIG. Is a time chart schematically enlarged on the time axis.

  In FIG. 5, when the bottom voltage Vi is Vi = Va, the bottom voltage Vi is a low voltage on the way to the target bottom voltage Vtar corresponding to the target rotational speed Nmtar.

  The target rotational speed Nmtar or the target bottom voltage Vtar (see FIG. 5) of the motor voltage Vm corresponding to the target rotational speed Nmtar is stored in the storage unit.

  Brake fluid is not stored in the reservoir 34 between the start time t0 of the EBD control and the time t1 until the time t1 at which the ABS control operation is started. For this reason, the motor 72 that drives the pump 70 is in the idling state from the time point t0 to the time point t1.

  As shown in FIGS. 4 and 5, ABS control is started for the front wheels at time t1.

  At this time t1, at the same time, in order to start the pressure reduction of the wheel cylinder pressure Pwca of the front wheel brake FR, the inlet valve 51 is excited to close the valve, and the outlet valve 52 is excited to a predetermined time (time t1). From time t3 to time t3), the valve is opened and the brake fluid is released from the front wheel brake fluid passage 106a to the reservoir 34 side through the outlet valve 52 and the escape fluid passage 108. Further, at time t3, the outlet valve 52 is demagnetized to be in a closed state so that the wheel cylinder pressure Pwca of the front wheel brake FR becomes a predetermined pressure between time t3 and time t5 when the valve is closed. Set and retained.

  Further, in order to increase the pressure of the rear wheel brake RL between the time point t1 and the time point t6, the inlet valve 61 is opened by a predetermined amount.

  In this case, the pump 70 sucks the brake fluid released to the reservoir 34 side from the suction liquid passage 110 and discharges it to the discharge liquid passage 118 with the start of the ABS pressure reduction control of the front wheels after the time point t1, so that the pump 70 is loaded. Therefore, the rotational speed Nm of the motor 72 that drives the pump 70 starts to drop from the time point t1.

After the time point t1, the ECU 16 detects the drop amount ΔNm at the time point t2 that is the bottom peak of the motor rotation speed Nm {see equation (1)} and the drop amount ΔVi {at the time point t2 that is the bottom peak of the bottom voltage Vi. (See formula (2)) is performed (corresponding to step S4).
ΔNm = Nmtar−Nmb (1)
ΔVi = Vtar−Vb (2)

  In the detection process of the rotational speed drop amount ΔNm, the drop amount ΔNm of the motor rotational speed Nm is the maximum from the time t1 when the motor rotational speed Nm starts to decrease (the peak value in the negative direction is on the waveform of the motor rotational speed Nm in FIG. 5). Since the process is to detect a point at which the maximum motor speed Nmb), the time t2 + α (before time t3) including that point and the period until the motor speed Nm rises again from the motor speed Nmb. Time point: When the differential value of the motor rotation speed Nm changes from negative to positive, since α is actually a minute time, it is continued until a period of t2 + α≈t2).

  The detection process of the bottom voltage drop amount ΔVi is a process of detecting a point where the drop amount ΔVi of the bottom voltage Vi is maximum (the bottom voltage Vb at which the peak value in the negative direction is maximum on the waveform of the motor voltage Vm in FIG. 5). Therefore, including that point, in FIG. 5, it continues until time t2 + α (time when the differential value of the bottom voltage Vi changes from negative to positive, α is a minute time, t2 + α≈t2) when time t2 has slightly passed. .

  At the time t2, the drop amount ΔNm of the motor rotation speed Nm or the drop amount ΔVi of the bottom voltage Vi is stored in the storage unit.

  The subsequent time point t4 indicates a time point when the motor rotation speed Nm has recovered to the target rotation speed Nmtar.

  Based on the drop amount ΔNm of the motor rotational speed Nm or the drop amount ΔVi of the bottom voltage Vi detected and stored at the time t2, refer to the characteristic 202 of FIG. 3 described in the processing of step S5 at the time t2. The estimated process of the master cylinder pressure Pmc is performed.

  The estimated master cylinder pressure Pmc can be immediately applied to the hydraulic pressure control after the estimated time t2.

  That is, when the estimated master cylinder pressure Pmc is used and the master cylinder pressure Pmc is used as a control parameter for the ABS control with EBD that the ECU 16 uses, for example, in FIG. Wheel brake FR pressure increase control (wheel cylinder pressure Pwca pressure increase control), rear wheel brake RL pressure increase control from time t8 to time t10 (wheel cylinder pressure Pwcb pressure increase control), and time The pressure increase control of the front wheel brake FR from t9 can be performed with high accuracy.

[Summary of Embodiment and Modifications]
As described above, the vehicular brake hydraulic pressure control device 10 according to the above-described embodiment is upstream of communicating with the master cylinder 12 as a hydraulic pressure source that generates brake hydraulic pressure by operating an operator such as the brake pedal 20. Provided between the side fluid passage 104 and the wheel brake fluid passages 106a, 106b communicating with the wheel cylinders 18a, 18b of the wheel brakes FR, RL and the relief fluid passage 108, and is applied to the wheel brakes FR, RL at the time of fluid pressure control. A control valve unit 30 for switching the brake fluid pressure to be reduced, increased or maintained, and a relief fluid passage 108 from the wheel cylinders 18a and 18b through the wheel brake fluid passages 106a and 106b and the control valve unit 30 during the pressure reduction. The reservoir 34 that stores the released brake fluid, the motor 72, and the motor 72 is used for driving. It is in the brake fluid from the reservoir 34 side by suction through the suction fluid passage 110 includes a pump 70 to the upstream side fluid passage 104 for discharging the discharge liquid passage 118 that communicates the control valve unit 30.

  The vehicle brake hydraulic pressure control device 10 further includes an ECU 16 as a control unit (hydraulic pressure control unit) that controls the control valve unit 30 and the motor 72 to perform the hydraulic pressure control.

  In this case, the ECU 16 rotates the motor 72 from before the start of the fluid pressure control (time t1) (time t0), and increases the motor load at the time of pressure reduction (from time t1 to time t3) immediately after the start of the fluid pressure control. An amount is obtained, and the brake fluid pressure (upstream brake fluid pressure) of the upstream fluid passage 104, in other words, the master cylinder pressure Pmc is estimated based on the obtained increase amount of the motor load.

  The higher the brake fluid pressure in the upstream fluid passage 104 that is the brake fluid discharge side of the pump 70, that is, the master cylinder pressure Pmc, the greater the load on the motor 72 when the pump 70 is changed from the stopped state to the operating state. Motor load increases. Therefore, even if the pressure sensor 82 is not provided, the hydraulic pressure control, in this embodiment, is rotated (idled) at a low load and the target rotational speed (constant rotational speed) Nmtar from the start of the pressure reduction control of the ABS control. Based on the increase in the load of the motor 72, the brake fluid pressure (master cylinder pressure Pmc) of the upstream fluid passage 104 of the control valve unit 30, in other words, the upstream fluid passage 104 of the inlet valves 51 and 61 is accurately estimated. can do. Since the pressure sensor 82 is not necessary, costs such as component cost, management cost, and assembly cost of the pressure sensor 82 can be reduced. In addition, since it is estimated from the increase in the load of the motor 72 immediately after the start time t1 of the hydraulic pressure control, the brake hydraulic pressure in the upstream side fluid passage 104 of the control valve unit 30 is increased immediately after the start of the hydraulic pressure control. Based on the estimated brake fluid pressure in the upstream fluid passage 104 of the control valve unit 30, that is, the master cylinder pressure Pmc, the fluid pressure control can be performed with high accuracy.

  In this case, the ECU 16 uses the characteristic 202 (see FIG. 3) of the upstream brake fluid pressure (master cylinder pressure Pmc) with respect to the increase amount of the motor load, which is associated in advance, as the upstream brake fluid pressure. By estimating the master cylinder pressure Pmc, the master cylinder pressure Pmc that is the upstream brake fluid pressure can be easily estimated from the increased amount of the motor load. The characteristic 202 can be obtained in advance by experiments, simulations, or the like.

  More specifically, the ECU 16 determines the increase amount of the motor load at the time of depressurization immediately after the start of the hydraulic pressure control (from the time t1 to the time t3) to the increase amount of the motor load immediately after the start of the hydraulic pressure control (from the time t1 to the time t3 ) May be obtained from a temporary drop amount ΔNm (ΔNm = Nmtar−Nmb) of the rotational speed Nm of the motor 72 or a drop amount ΔVi (ΔVi = Vtar−Vb) of the bottom voltage Vi of the motor 72. In this case, as the upstream brake fluid pressure, which is associated in advance with respect to the temporary drop amount ΔNm of the rotational speed Nm of the motor 72 at the time of pressure reduction immediately after the start of the fluid pressure control (from time t1 to time t3). The master cylinder pressure Pmc as the upstream brake fluid pressure is estimated using the master cylinder pressure Pmc characteristic 202 (FIG. 3), or at the time of pressure reduction immediately after the start of the fluid pressure control (from time t1 to time t3). ) To estimate the master cylinder pressure Pmc as the upstream brake fluid pressure with respect to the drop amount ΔVi of the bottom voltage Vi of the motor 72, so that the control valve unit 30 communicating with the master cylinder 12 has the upstream brake fluid pressure as the upstream brake fluid pressure. The master cylinder pressure Pmc can be easily estimated with high accuracy. The characteristic 202 can be obtained in advance by experiments, simulations, or the like.

  Further, the present invention is not limited to the above-described embodiment, and various configurations ([modifications]) can be adopted based on the description of this specification.

[Modification]
For example, in the above-described embodiment, the master cylinder 12 and the control valve unit 30 are configured to communicate with each other via the upstream liquid passage 104, but not limited thereto, as shown in FIG. Provided between the master cylinder 12 and the control valve unit 30 is a regulator composed of a normally open cut valve (switching valve) provided with a relief valve in parallel, and further, an upstream liquid passage 104 and a pump communicating with the control valve unit 30 70 is applied to a brake fluid pressure control device for a vehicle having a configuration in which a normally closed suction valve is provided between the suction fluid passages 110 of 70 and the upstream brake fluid pressure of the control valve unit 30 is estimated. You can also. In the vehicular brake hydraulic pressure control apparatus configured as described above, as is well known, a brake hydraulic pressure larger than the brake hydraulic pressure generated by the operation of the operator such as the brake pedal 20 of the driver is generated. Brake assist control (BA control) becomes possible.

10 ... Vehicle brake hydraulic pressure control device 12 ... Master cylinder (hydraulic pressure source)
DESCRIPTION OF SYMBOLS 16 ... ECU (control part) 30 ... Control valve unit 34 ... Reservoir 70 ... Pump 103, 104 ... Upstream side fluid passage 106a, 106b ... Wheel brake fluid passage 108 ... Escape fluid passage 110 ... Intake fluid passage 118 ... Discharge fluid passage FR , FL ... wheel brake Pmc ... master cylinder pressure Pwc (Pwca, Pwcb) ... wheel cylinder pressure

Claims (3)

Control that switches the brake fluid pressure acting on the wheel brake to a reduced, increased, or maintained state provided in the fluid path of the brake fluid from the fluid pressure source that generates the brake fluid pressure by the operation of the operator to the wheel brake A valve unit;
A reservoir for storing the brake fluid released from the wheel brake through the control valve unit during the decompression;
A motor,
A pump that is driven by the motor and sucks the brake fluid from the reservoir side, and discharges the brake fluid to an upstream fluid passage of the control valve unit;
A brake fluid pressure control device for a vehicle comprising:
Rotate the motor before the start of the hydraulic pressure control, determine the amount of increase in the motor load during pressure reduction immediately after the start of the hydraulic pressure control,
A brake fluid pressure control device for a vehicle, wherein the brake fluid pressure in the upstream fluid passage is estimated based on the obtained increase amount of the motor load. The vehicle brake hydraulic pressure control device according to claim 1,
When estimating the brake fluid pressure of the upstream fluid passage, the brake of the upstream fluid passage is preliminarily associated with the brake fluid pressure characteristic of the upstream fluid passage with respect to the increase amount of the motor load. A brake fluid pressure control device for a vehicle characterized by estimating a fluid pressure. The vehicle brake hydraulic pressure control device according to claim 1 or 2,
The increase amount of the motor load at the time of depressurization immediately after the start of the hydraulic pressure control is obtained from the amount of decrease in the rotation speed of the motor or the amount of decrease in the voltage of the motor at the time of depressurization immediately after the start of the hydraulic pressure control. A brake fluid pressure control device for a vehicle.

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