JP5098419B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake control device.

Patent Document 1 includes a first hydraulic pipe including first and second wheel cylinders, and a second hydraulic pipe including third and fourth wheel cylinders, depending on the vehicle running state. A vehicle brake device is described in which the brake hydraulic pressure distribution of the two hydraulic pipes is adjusted to adjust the brake hydraulic pressure distribution of the wheels.
Japanese Patent Laid-Open No. 9-290731

  More specifically, in this apparatus, a hydraulic pump that generates an auxiliary hydraulic pressure added to the master cylinder pressure is provided in one of the two hydraulic pipings. At the time of a braking operation in a straight vehicle state, the master cylinder pressure itself is supplied to the two hydraulic pipes. On the other hand, at the time of a braking operation in a state where the steering operation angle is large (vehicle turning state), the hydraulic pump is operated and a braking hydraulic pressure larger than the master cylinder pressure is supplied to the one hydraulic piping. Thus, it is described that a larger braking force can be obtained during a braking operation in a vehicle turning state than in a braking operation in a vehicle straight traveling state.

  However, this means that the vehicle deceleration increase characteristic (the relationship between the braking operation amount and the vehicle deceleration) differs between the vehicle turning state and the vehicle straight traveling state. In general, it is considered preferable that the increase characteristic of the vehicle deceleration with respect to the braking operation amount is kept constant even if the brake hydraulic pressure distribution of the wheels is changed.

  On the other hand, when braking is performed during turning (hereinafter referred to as “turning braking”) and when turning is performed during braking (hereinafter referred to as “braking turning”), the vehicle. The behavior is different. Hereinafter, this will be described with reference to FIG.

  A pneumatic tire (also simply referred to as a tire or a wheel) generates a force (friction force) due to friction with the road surface, specifically, slip between the tire and the road surface. The front / rear force of the tire is generated by a slip in the tire traveling direction (front / rear direction) (a front / rear slip, which is represented by a slip ratio). The lateral force of the tire (the cornering force with respect to the vehicle body) is also generated by a slip in the lateral direction of the tire (a lateral slip, expressed by a slip angle that is an angle between the tire traveling direction and the direction in which the tire faces).

  When the vehicle is making a steady circular turn at a constant speed, a slip angle occurs on the front and rear wheels, the front cornering force and the rear cornering force are balanced, and the sum of the cornering forces of each wheel acts on the vehicle. Balance with centrifugal force. Thus, the vehicle can travel along the turning circle.

  When the vehicle is decelerated by braking in this turning state (when turning braking), the ground load moves from the rear wheel to the front wheel. As a result, the cornering force of the front wheels increases and the cornering force of the rear wheels decreases. Due to this cornering force imbalance, a turning inward yawing moment is generated, and the vehicle is caught in the direction of the inside of the turning circle (an oversteer tendency occurs). In this case, in FIG. 20, it corresponds to the movement state of the vehicle shifting from the point Yo to the point A by a braking operation.

  Next, the case of braking turning will be described. For example, when a turning operation is performed during linear braking, in FIG. 20, this corresponds to the movement state of the vehicle shifting from the point Xo to the point A by the turning operation. When braking is performed and a tire slips back and forth, even if a slip angle is given to the tire, the magnitude of the lateral force of the tire is smaller than that during non-braking. For this reason, the cornering force generated when the steering wheel is given a slip angle by the steering operation is smaller than that during non-braking. Therefore, the turning ability of the vehicle (response characteristics that the vehicle changes its traveling direction) is not sufficient.

  As described above, the vehicle behavior caused by the braking operation during turning is different from the vehicle behavior caused by the turning operation during braking, and it is necessary to improve the stability of the vehicle at the time of turning braking. It is necessary to improve the turning ability of the vehicle.

  The present invention has been made on the basis of such knowledge, and an object of the present invention is to maintain a vehicle deceleration increasing characteristic with respect to a braking operation amount substantially constant in a vehicle braking control device including two hydraulic pipings. On the other hand, an object of the present invention is to provide a vehicle that can improve the stability of the vehicle during turning braking and can improve the turning ability of the vehicle during braking turning.

  The vehicle braking control device according to the present invention includes four wheel braking devices that respectively apply braking torque corresponding to the braking hydraulic pressure supplied to the wheel cylinders of the four front, rear, left, and right wheels of the vehicle to the corresponding wheels, A first hydraulic pressure generating device (master cylinder) having two hydraulic pressure generating chambers each generating a hydraulic pressure amount corresponding to a braking operation amount by a driver of the vehicle, and of the two hydraulic pressure generating chambers, A first hydraulic pipe that hydraulically connects one of the four wheel braking devices corresponding to the left and right front wheels or two corresponding to the left front wheel and the right rear wheel; and the two hydraulic pressures A second hydraulic piping that hydraulically connects the other of the generation chambers to two of the four wheel braking devices corresponding to the left and right rear wheels or two corresponding to the right front wheel and the left rear wheel; Is provided. In other words, the vehicle braking control device may include a so-called “front and rear pipe” or a so-called “diagonal pipe (also referred to as X pipe)”.

Vehicle brake control device according to the present invention generates the first, the assisting pressure to be added to the generated the liquid amount of pressure by the first hydraulic pressure generator in each of the second liquid pressure piping A power-driven second hydraulic pressure generator (hydraulic pump), a braking operation amount detection means for detecting the braking operation amount, and a turning state amount detection means for detecting a turning state amount representing a turning motion of the vehicle; , An assisting hydraulic pressure amount for determining a first assisting hydraulic pressure amount in the first hydraulic pressure pipe and a second assisting hydraulic pressure amount in the second hydraulic pressure pipe based on the detected braking operation amount. Determining means, stabilized basic hydraulic pressure amount determining means for determining a stabilized basic hydraulic pressure amount in the first and second hydraulic pipes based on the detected braking operation amount, and braking by the driver The braking opening detected as the turning state quantity at the start of the operation State determining means for detecting a first state when the turning state quantity is greater than or equal to a first predetermined value and detecting a second state when the braking start turning state quantity is less than the first predetermined value; When one state is detected, based on the detected turning state amount, the two wheel braking devices or the turning outer front wheel and the turning corresponding to the left and right front wheels of the first and second hydraulic pipes The first assist hydraulic pressure target amount in one hydraulic pipe connected to the two wheel braking devices corresponding to the inner rear wheel is the one of the determined first and second assist hydraulic pressure amounts. The first assist hydraulic pressure amount corresponding to the hydraulic pipe is determined to be greater than or equal to the first hydraulic pressure pipe, and the second assist hydraulic pressure target amount in the other hydraulic pipe among the first and second hydraulic pipes is determined. 1 and the second assisting hydraulic pressure amount is determined to be less than the other assisting hydraulic pressure amount, When the state is detected, the first assisting hydraulic pressure target amount is determined to be equal to or less than the one assisting hydraulic pressure amount based on the detected turning state amount, and the second assisting hydraulic pressure target is determined. Assistance hydraulic pressure target amount determination means for determining the amount to be equal to or greater than the other assisting hydraulic pressure amount, and the assisting hydraulic pressure in each of the one and other hydraulic pressure pipes, the determined first and second assisting forces. Pressure adjusting means for adjusting to match the respective hydraulic pressure target amounts.

  At the time of turning braking, the turning state amount (= the braking start turning state amount) at the start of the braking operation is large. At the time of braking turning, the braking start turning state amount is small. Therefore, according to the determination means, it is possible to determine when the vehicle is turning and braking (corresponding to the first state) and when it is braking and turning (corresponding to the second state).

  First, the case of front and rear piping will be described. According to the above configuration, when it is determined that the vehicle is in turning braking (first state), based on the detected amount of turning state, the braking hydraulic pressure of the front wheel hydraulic pipe (master cylinder pressure + front wheel assisting fluid) Pressure) is adjusted to a value equal to or higher than the front wheel reference hydraulic pressure (master cylinder pressure + front wheel assist hydraulic pressure reference amount), and the brake hydraulic pressure of the rear wheel hydraulic pipe (master cylinder pressure + rear wheel assist hydraulic pressure). ) Is adjusted to a value equal to or lower than the reference hydraulic pressure of the rear wheels (master cylinder pressure + rear wheel assist hydraulic pressure reference amount). In other words, the hydraulic pressure of the hydraulic piping of the front wheels (ie, the braking hydraulic pressure of the left and right front wheels) is increased and corrected relative to the corresponding reference hydraulic pressure, and the hydraulic pressure of the hydraulic piping of the rear wheels (ie, the left and right rear wheels). (Braking hydraulic pressure) is reduced and corrected with respect to the corresponding reference hydraulic pressure (hereinafter referred to as “turning braking control”).

  Accordingly, the cornering force of the left and right front wheels decreases to reduce the inward turning yawing moment, and the cornering force of the left and right rear wheels increases to increase the outward turning yawing moment. As a result, it is possible to improve the stability of the vehicle during turning braking while maintaining the increase characteristic of the vehicle deceleration with respect to the braking operation amount substantially constant.

  On the other hand, according to the above configuration, when it is determined that the vehicle is in a braking turn (second state), based on the detected turning state amount, the braking hydraulic pressure (master cylinder pressure + front wheel The assist hydraulic pressure is adjusted to a value equal to or less than the front wheel reference hydraulic pressure (master cylinder pressure + front wheel assist hydraulic pressure reference amount), and the brake hydraulic pressure of the rear wheel hydraulic piping (master cylinder pressure + rear wheel assist). (Hydraulic pressure) is adjusted to a value equal to or higher than the reference hydraulic pressure of the rear wheel (master cylinder pressure + rear wheel assist hydraulic pressure reference amount). In other words, the hydraulic pressure of the front-wheel hydraulic piping (ie, the braking hydraulic pressure of the left and right front wheels) is reduced and corrected relative to the corresponding reference hydraulic pressure, and the hydraulic pressure of the rear-wheel hydraulic piping (ie, the left and right rear wheels). (Braking hydraulic pressure) is increased and corrected with respect to the corresponding reference hydraulic pressure (hereinafter referred to as “braking turning control”).

  Accordingly, the cornering force of the left and right front wheels increases to increase the turning inward yawing moment, and the cornering force of the left and right rear wheels decreases to decrease the turning outward yawing moment. As a result, it is possible to improve the turning performance of the vehicle during the braking turn while maintaining the increase characteristic of the vehicle deceleration with respect to the braking operation amount substantially constant.

  Next, the case of diagonal piping will be described. According to the above configuration, when it is determined that the vehicle is in turning braking (first state), the hydraulic pipes corresponding to the turning outer front wheel and the turning inner rear wheel (one liquid) are determined based on the detected turning state amount. The hydraulic pressure of the pressure pipe (that is, the braking hydraulic pressure of the two wheels corresponding to one hydraulic pipe) is increased and corrected with respect to the corresponding reference hydraulic pressure, and the hydraulic pressure corresponding to the turning inner front wheel and the turning outer rear wheel. The hydraulic pressure of the pipe (the other hydraulic pipe) (that is, the brake hydraulic pressure of the two wheels corresponding to the other hydraulic pipe) is reduced and corrected with respect to the corresponding reference hydraulic pressure (turning braking control).

  Accordingly, a difference in braking force between the left and right front wheels is generated, and a turning outward yawing moment is generated. In addition, the cornering force of the turning outer front wheel is reduced and the turning inward yawing moment is reduced. As a result, it is possible to improve the stability of the vehicle during turning braking while maintaining the increase characteristic of the vehicle deceleration with respect to the braking operation amount substantially constant.

  On the other hand, according to the above configuration, when it is determined that the brake is turning (second state), the hydraulic pressure of the one hydraulic pipe (that is, one hydraulic pressure) is determined based on the detected turning state amount. The brake hydraulic pressure of the two wheels corresponding to the pipe is reduced and corrected with respect to the corresponding reference hydraulic pressure, and the hydraulic pressure of the other hydraulic pipe (that is, the brake hydraulic pressure of the two wheels corresponding to the other hydraulic pipe) ) Is corrected with respect to the corresponding reference hydraulic pressure (braking turning control).

  Accordingly, a difference in braking force between the left and right front wheels is generated, and a yawing moment inwardly turning is generated. In addition, the cornering force of the outer front wheel of the turning increases and the yawing moment inward of the turning increases. As a result, it is possible to improve the turning performance of the vehicle during the braking turn while maintaining the increase characteristic of the vehicle deceleration with respect to the braking operation amount substantially constant.

  As described above, according to the vehicle brake control device of the present invention, in the case of front and rear piping or diagonal piping, the increase characteristic of the vehicle deceleration with respect to the amount of braking operation is maintained substantially constant, and at the time of turning braking. The stability of the vehicle can be improved, and the turning ability of the vehicle can be improved during braking turning.

  As described above, in the vehicle brake control device according to the present invention, the “turning braking control” is executed when the braking start turning state quantity is equal to or greater than the first predetermined value, and the braking start turning state quantity is When it is less than the first predetermined value, “braking turning control” is executed.

  On the other hand, when the braking start turning state quantity is not less than the first predetermined value, “turning braking control” is executed, and the braking start turning state quantity is not less than the second predetermined value which is smaller than the first predetermined value. Thus, the brake control may not be executed when it is less than the first predetermined value, and “brake turn control” may be executed when the braking start turning state quantity is less than the second predetermined value.

  When braking is started in a state where the turning braking amount (lateral acceleration, etc.) is within a certain range, the vehicle is caught in the inside of the turning circle because the degree of cornering force imbalance between the front and rear wheels is small. There is little tendency to be. In this case, the turning ability of the vehicle is sufficiently ensured even if “braking turning control” is not performed, and the stability of the vehicle can be sufficiently maintained even if “turning braking control” is not performed. . Therefore, the necessity of performing “turning braking control” and “braking turning control” is low. The above configuration is based on such knowledge. According to this, it is possible to suppress unnecessary execution of the “turning braking control” or the “braking turning control” when the necessity of performing the “turning braking control” and the “braking turning control” is low. .

  Further, “turning braking control” is executed when the braking start turning state amount is equal to or greater than the first predetermined value, and braking control is not executed when the braking start turning state amount is less than the first predetermined value. It may be configured. This configuration is particularly effective when the turning characteristics of the vehicle are tuned so that the turning ability of the vehicle is sufficiently ensured during braking turning without performing “braking turning control”.

  Similarly, braking control is not executed when the braking start turning state quantity is greater than or equal to the first predetermined value, and “braking turning control” is executed when the braking start turning state quantity is less than the first predetermined value. You may be comprised so that. This configuration is particularly effective when the turning characteristics of the vehicle are tuned so that the stability of the vehicle is sufficiently ensured during turning braking without performing “turning braking control”.

In the vehicle brake control device according to the present invention, the assist hydraulic pressure target amount determination means includes:
Based on the detected braking operation amount, the stabilized basic hydraulic pressure amount in the first and second hydraulic pipes is determined to be zero when the detected braking operation amount is less than a predetermined operation amount greater than zero. In addition, when the braking operation amount is larger than the predetermined operation amount, the stabilization basic hydraulic pressure amount determining means that determines a value larger than zero, and the one or the other hydraulic piping according to the detected state The first and second stabilizing hydraulic pressure amounts in the are determined to values obtained by multiplying the determined stabilized basic hydraulic pressure amount by predetermined coefficients obtained based on the detected turning state amount, respectively. And the assisting hydraulic pressure target amount determining means sets the first assisting hydraulic pressure target amount to the one assisting hydraulic pressure reference amount as the first stabilizing hydraulic pressure amount. To obtain a value obtained by adding the second assist hydraulic pressure target amount , It is preferably configured to determine a value obtained by adding the second stabilizing solution pressure amount in the assisting pressure reference amount of the other.

  According to this, when the braking operation amount is equal to or less than the predetermined operation amount (> 0), the first and second stabilizing hydraulic pressure amounts are set to zero. That is, the first and second assist hydraulic pressure target amounts are respectively determined to be equal to the other assist hydraulic pressure reference amount. In other words, when the braking operation amount is equal to or less than the predetermined operation amount, neither “turning braking control” nor “braking turning control” is performed. Here, when the amount of braking operation is small, i.e., when the vehicle deceleration is small, the problems of a decrease in the stability of the vehicle and a decrease in the turning ability hardly occur. That is, according to the above configuration, when the necessity of performing “turning braking control” and “braking turning control” is low, it is possible to suppress unnecessary execution of “turning braking control” or “braking turning control”. be able to.

  Embodiments of a vehicle brake control device according to the present invention will be described below with reference to the drawings.

<Overall configuration of the device>
First, the overall configuration of the vehicle brake control device according to the embodiment will be described with reference to FIGS. 1 and 2. In FIG. 1 and FIG. 2, the case where the brake piping is “front and rear piping” is mainly shown, and the case of “diagonal piping (also referred to as X piping)” is shown in parentheses. The same applies to other figures.

  The first pressure generating means (corresponding to the “first hydraulic pressure generating device”) is the master cylinder MC. The master cylinder MC has two hydraulic pressure generation chambers (not shown), and generates a braking pressure (hydraulic pressure) in response to the driver's operation (braking operation) of the brake pedal BP. That is, the braking pressure is generated using the power generated by the driver as a power source. Furthermore, in order to reduce the brake pedal operating force, the master cylinder MC can be provided with a vacuum booster VB (also referred to as a negative pressure booster or a brake booster).

  The second pressure generating means (corresponding to the “second hydraulic pressure generating device”) is a fluid pump HP # (also referred to as a hydraulic pump, hereinafter simply referred to as a pump) driven by an electric motor M, and is operated. The braking pressure is generated by a power source (for example, a power source) that is separate from the person's power. The pump HP # sucks a part of the fluid discharged from the master cylinder MC and discharges it to the wheel cylinder WC **.

  Here, “#” is a subscript indicating each system in the two systems of braking piping (hydraulic piping). When the brake pipe is a front and rear pipe, “f” represents the front wheel system, “r” represents the rear wheel system, and when the brake pipe is a diagonal pipe, “1” represents the first system and “2” represents the second system. Represents. The subscript “#” is the same in the following. “**” is a subscript meaning each wheel, “fl” represents the left front wheel, “fr” represents the right front wheel, “rl” represents the left rear wheel, and “rr” represents the right rear wheel. The subscript “**” is the same in the following.

  In this way, the pump HP # sucks the fluid from the pipe part LM # and discharges it to the pipe part LW **. For this reason, the movement of the fluid occurs, and an auxiliary braking pressure is generated with respect to the braking pressure generated by the master cylinder MC.

  The detection means BS detects the braking operation amount Bs by the driver's braking operation member (for example, the brake pedal BP). Specifically, the braking pressure (master cylinder pressure Pm #) in the master cylinder MC or two braking pipes (first and second hydraulic pipes) connected to the two hydraulic pressure generation chambers of the master cylinder MC, respectively. Is detected. Therefore, the master cylinder pressure Pm # can be used as the braking operation amount Bs. Further, the displacement (stroke) and operating force of the brake pedal BP can be detected, and these detected values (brake pedal stroke or brake pedal operating force) can be used as the braking operation amount Bs.

  The pressure adjusting means (corresponding to the “pressure adjusting means”) is, for example, a linear pressure adjusting valve LV # (also referred to as a linear solenoid valve or a linear control valve), and is generated by a second pressure generating means (pump / electric motor). The pressure is adjusted based on an auxiliary pressure target value SP # t described later. Then, the braking pressure generated by the second pressure generating means (pump / electric motor) is added to the braking pressure generated by the first pressure generating means (master cylinder MC) and applied to the wheel cylinder WC **. The number of rotations of the electric motor M is controlled to generate a necessary pressure, and the final pressure adjustment is performed by the linear solenoid valve LV #.

  The pressure increase limiting means, which is a brake pressure increase limiting means, is used when the braking pressure Ph # in the pump discharge side pipe is higher than the braking pressure Pw ** in the wheel cylinder. Limit the slope of the increase towards #. For example, an inlet valve IV ** (also referred to as a pressure increasing solenoid valve) used for ABS control can be used.

  Further, the depressurization limiting means, which is a limiting means for reducing the brake pressure, limits the gradient of the decrease in the brake pressure Pw ** in the wheel cylinder. For example, an outlet valve OV ** (also referred to as a pressure reducing solenoid valve) used for ABS control can be used.

《Brake control configuration》
Next, the configuration of the braking control by the vehicle braking control apparatus according to the embodiment will be described with reference to FIG.

<Calculation of assistance pressure SP # o>
The reference value of the pressure (pressure added to the braking pressure) for assisting (assisting) the braking pressure generated by the first pressure generating means (master cylinder MC) is the operation amount of the braking member (brake pedal BP) of the driver. (Hereinafter referred to as braking operation amount Bs). The braking operation amount Bs is calculated based on the detection result of the braking operation amount detection means BS (using at least one of the brake pedal stroke sensor, the brake pedal operation force sensor, and the master cylinder pressure sensor PM #). The The braking pressure generated by the master cylinder MC is the same as the pressure in the piping part LM #.

  The purpose of the driver's braking operation is to decelerate the vehicle (vehicle body). The braking device presses the brake pad against the brake rotor by the braking pressure, and generates a braking force on the wheel by the frictional force at that time. For this reason, the target of braking control is pressure (pressure of fluid in the wheel cylinder). Therefore, it is desirable to use the master cylinder pressure Pm # that is the same physical quantity as the braking operation amount Bs.

  The method for determining the reference value of the assist pressure (corresponding to the above-mentioned “assistance hydraulic pressure reference amount”; hereinafter also simply referred to as assist pressure SP # o) is somewhat different depending on the type of the brake pipe. To do.

  Based on the vehicle reference specifications, the braking force distribution between the front and rear wheels (front / rear braking force distribution) is calculated based on the braking operation amount Bs of the driver. The standard specifications of the vehicle are values such as the vehicle weight Ms, the position of the center of gravity, the wheel base L, and the like, and are values that vary depending on the occupant and the loading state. It is the value.

  The assisting pressure SP # o (SPfo, SPro) is a so-called ideal braking force distribution (a distribution in which the braking force of the front and rear wheels becomes a braking force proportional to each load in consideration of load movement at the time of braking) or an approximation thereto. It is calculated from the braking force distribution characteristic.

  FIG. 4 is a table of the assisting pressures SPfo and SPro for the front wheels and the rear wheels with respect to the braking operation amount Bs. In this case, the assist pressure SP # o increases proportionally (linearly) from “0” in accordance with the increase in the braking operation amount Bs from “0”. The front wheel and rear wheel assist pressures SPfo and SPro may be the same value or different.

  Further, as shown in FIG. 5, the front wheel assist pressure SPfo can be set to increase from “0” with a “convex downward” characteristic in response to an increase in the braking operation amount Bs from “0” ( (See solid line). Alternatively, as indicated by a dashed line approximating the characteristic of “convex downward”, it is also set to increase from “0” by a plurality of straight lines whose inclination increases as the braking operation amount Bs increases from “0”. Can be done.

  On the other hand, the assist pressure SPro for the rear wheels can be set to increase from “0” with a “convex upward” characteristic in response to an increase in the braking operation amount Bs from “0” (see the solid line). Alternatively, as indicated by a broken line approximating the characteristic of “convex upward”, it is also set to increase from “0” by a plurality of straight lines whose inclination decreases as the braking operation amount Bs increases from “0”. Can be done. Thus, the braking force distribution between the front and rear wheels can be made closer to the ideal braking force distribution.

  On the other hand, when the brake pipe is a diagonal pipe, the assist pressures SP1o and SP2o are calculated with the same characteristics in the first and second systems as shown in FIG. In this case, as shown by the solid line, the assist pressure SP # o may be set so as to increase proportionally (linearly) from “0” in accordance with the increase in the braking operation amount Bs from “0”. However, as indicated by a broken line, it may be set to increase from “0” with the characteristic of “convex downward” in accordance with the increase in the braking operation amount Bs from “0”.

  In setting the assisting pressure, an arbitrary amount of braking operation can be set as the starting point (starting point) for applying the assisting pressure. Here, it is desirable that a minute braking operation amount including “0” (“0” or a minute value in the vicinity of “0”) be a starting point for applying the assisting pressure. Although the operation characteristic of the brake pedal BP is changed by the application of the assisting pressure, a sense of discomfort to the driver can be suppressed by using a small amount of braking operation including “0” as a starting point for the application of the assisting pressure.

  Further, when a negative pressure booster is provided as a booster (assisting device), as shown by a solid line in FIG. 7, the starting point (timing) of applying the assisting pressure is determined by the jump-in of the negative pressure booster (helper of the booster). It is desirable to make it coincide with the point (timing, corresponding to the point Bsp in FIG. 7) where the force increases from zero (step characteristic, also called jumping). When two types of boosting actions with different operating principles, ie, a boosting action (assisting action) due to negative pressure and a boosting action (assisting action) due to assisting pressure are combined, the boosting action (assisting action) starts to occur. By making the braking operation amount (starting point) the same, a sense of incongruity with respect to the braking operation can be suppressed. Further, as shown by a broken line in FIG. 7, the assist pressure characteristic has the same effect as the jump-in effect of the negative pressure booster, and the assist pressure is set to rapidly increase to the value J1 at the jump-in point Bsp. You can also. As described above, the means for determining the assist pressure SP # o (corresponding to the “first and second assist hydraulic pressure reference amounts”) corresponds to the “assistance hydraulic pressure reference amount determining means”.

<Calculation of stabilization pressure>
Next, the calculation of the stabilization pressure SP # s will be described with reference to FIG. The stabilization pressure SP # s is added to the assisting pressure SP # o to discriminate between turning braking and braking turning, and improving the stability and turning ability of the vehicle. A target value SP # t (= SP # o + SP # s) is calculated.

  As will be described later, the stabilization pressure SP # s is calculated by multiplying the stabilization base pressure SA # o by a coefficient (a turning braking coefficient Kt #, a braking turning coefficient Ks #, “0 (inhibition of braking control)”). The Therefore, the auxiliary pressure target value SP # t is calculated by increasing or decreasing the stabilization pressure SP # s with respect to the assisting pressure SP # o according to the coefficient. When braking control is prohibited (coefficient = 0), the auxiliary pressure target value SP # t coincides with the assisting pressure SP # o.

Calculation of Stabilization Base Pressure SA # o In order to calculate the stabilization pressure SP # s, as shown in FIG. 9, the stabilization base pressure SA # o is calculated based on the braking operation amount Bs. Here, the value Bsq is a braking operation amount that permits application of the stabilization pressure. When the vehicle deceleration is small, the problem of a decrease in vehicle stability and a decrease in turnability does not occur so much, so the value Bsq can be set to a value corresponding to a vehicle deceleration of about 0.1G. Thus, the means for determining the stabilization basic pressure SA # o (corresponding to the “stabilized basic hydraulic pressure amount”) corresponds to the “stabilized basic hydraulic pressure amount determining means”.

Calculation of turning braking coefficient Kt # The turning braking coefficient Kt # is a control coefficient for performing turning braking control. Specifically, the stabilization pressure SP # s during turning braking is calculated by multiplying the stabilization base pressure SA # o by the coefficient Kt #. The turning braking coefficient Kt # is calculated based on the turning state amount Tc using the characteristic (referred to as the first characteristic) shown in FIG.

  The turning state amount Tc is calculated based on the detection result of the turning state amount detection means TC. The turning state amount Tc is a state amount representing the turning motion of the vehicle, and is a value calculated based on at least one of a steering wheel operation angle, a steering wheel steering angle, a lateral acceleration, and a yaw rate. .

  It is desirable to use the actual lateral acceleration Gya as the turning state amount Tc. In the first characteristic, the turning braking coefficient Kt # of the front-wheel braking piping system for the front and rear piping and the braking piping system including the turning outer front wheel for the diagonal piping starts from the value Gyp based on the turning state amount Tc. Is set to a value greater than or equal to “0”. Thereby, the stabilization pressure SP # s is set to a value of “0” or more.

  Further, according to the first characteristic, the turning braking coefficient Kt # of the rear wheel braking piping system for the front and rear piping and the braking piping system including the turning inner front wheel for the diagonal piping is a value based on the turning state amount Tc. The value is set to “0” or less starting from Gyp. Thereby, the stabilization pressure SP # s is set to a value of “0” or less.

  This first characteristic can be made variable according to the vehicle speed Vx (or the vehicle speed Vxo at the start of braking). In this case, the absolute value | Kt # | of the turning braking coefficient can be set to increase as the vehicle body speed Vx (or Vxo) increases.

Calculation of braking / turning coefficient Ks # The braking / turning coefficient Ks # is a control coefficient for performing braking / turning control. Specifically, the stabilization pressure SP # s during braking turning is calculated by multiplying the stabilization base pressure SA # o by the coefficient Ks #. The braking turning coefficient Ks # is calculated based on the turning state amount Tc using the characteristic (referred to as the second characteristic) shown in FIG.

Here, it is desirable to use a value calculated based on the steering wheel operation angle θsw (or the steering wheel steering angle δf) as the turning state amount Tc. For example, based on the steering wheel operation angle θsw, the calculated lateral acceleration Gye = (Vx ² · θsw) / {L · N · (1 + Kh · Vx ² )} (where L is the wheel base, N is the steering gear ratio, Kh is a stability factor), which can be used as the turning state amount Tc.

  In the second characteristic, the braking turning coefficient Ks # of the rear braking brake system in the case of front and rear piping and the braking piping system including the turning inner front wheel in the case of diagonal piping has a value Gyq based on the turning state amount Tc. The starting point is set to a value of “0” or more. Thereby, the stabilization pressure SP # s is set to a value of “0” or more.

  Further, in the second characteristic, the braking turning coefficient Ks # of the front wheel braking piping system in the case of front and rear piping and the braking piping system including the turning outer front wheel in the case of diagonal piping is a value Gyq based on the turning state amount Tc. Is set to a value equal to or less than “0”. Thereby, the stabilization pressure SP # s is set to a value of “0” or less.

  This second characteristic can be made variable according to the steering wheel operation speed (angular speed) dθsw (or the steering wheel angular speed dδf). In this case, the absolute value | Ks # | of the braking / turning coefficient can be set to increase as dθsw (or δf) increases. The steering wheel operation angular velocity dθsw is obtained by differentiating the operation angle θsw.

・ Distinction between “turning braking” and “braking turning” The selection means determines whether to “turn braking (select turning braking coefficient Kt #)” and “brake turning (select braking turning coefficient Ks #)”. This is performed based on the turning state amount when the operation is started (corresponding to the “braking start turning state amount”). When the braking operation amount Bs becomes equal to or greater than the predetermined value Bs1, it is determined that braking is started, and the turning state amount at this time is stored as the braking start turning state amount Tco. When the braking start turning state amount Tco is equal to or greater than the predetermined value Tc1, it is determined that the vehicle is “turning braking (referred to as turning braking control)”. On the other hand, when the braking start turning state amount Tco is less than the predetermined value Tc1, it is determined as “braking turning (referred to as braking turning control)”.

  Vehicle stability is determined by the degree of balance (balance) of forces generated by wheels (tires). From such a viewpoint, it is desirable to use the actual lateral acceleration Gya detected by the lateral acceleration sensor GY, which appears as a result of the wheel generating force, as the turning state quantity. A value corresponding to the actual lateral acceleration Gya at the start of braking is stored as the braking start turning state quantity Tco. By comparing this value Tco with a predetermined value Tc1 (≈0.5G), “turning braking” and “braking turning” are determined, and “turning braking control” or “braking turning control” is determined. Selected.

  In the above, one of two types of “turning braking control” and “braking turning control” is selected, but “turning braking control (coefficient Kt #)”, “prohibition of braking control (coefficient = 0)”. And “braking turning control (coefficient Ks #)” can be discriminated and one of these three types can be selected. In this case, when the predetermined value Tc2 (for example, 0.5 G) or more, “turning braking control”, when less than the predetermined value Tc2 and more than the predetermined value Tc3 (for example, 0.3 G), “braking control prohibition”, predetermined When the value is less than the value Tc3, "braking turning control" can be executed. When only two types of “turning braking control” and “braking turning control” are determined, the “braking control prohibition” block is omitted in FIG.

  In addition, the master cylinder, the wheel cylinder, and the assisting pressure are provided so that any one of the turning performance (stability) and the turning performance (turning performance) of the vehicle can be sufficiently secured when the braking control is not executed. Etc. can be set. In this case, any one of the turning braking control and the braking turning control may be executed. That is, although the above determination is necessary, the control of any one of the turning braking control and the braking turning control is combined with the prohibition of the braking control.

  Multiplying the stabilization basic pressure SA # o by the coefficient (Kt #, Ks #, or “1 (may be omitted)”) selected by the selection means, the final stabilization pressure SP # s ( Target value) is calculated. The means for determining the stabilization pressure SP # s (corresponding to the “first and second stabilization fluid pressure amounts”) corresponds to the “stabilization fluid pressure amount determination means”.

  Then, the stabilization pressure SP # s is added to the assist pressure SP # o, and the final target value SP # t (= SP # s + SP # o) of the assist pressure is determined. Thus, the means for determining the auxiliary pressure target value SP # t (corresponding to the “first and second assisting hydraulic pressure target amounts”) corresponds to the “assisting hydraulic pressure target amount determining means”. The auxiliary pressure is formed by second pressure generating means (for example, an electric motor / pump), and is adjusted by pressure adjusting means (for example, a linear pressure regulating valve).

・ Calculation of pressure increase / decompression restriction The pressure of the brake piping on the pump discharge side increases / decreases (changes) due to the stabilization pressure SP # s, but the braking pressure on one side of the wheels connected to the brake piping changes In some cases, it is desired to limit the change in the braking pressure on the other side. In particular, when the braking pipe pressure is increased by the stabilization pressure SP # s, by restricting the increase in the braking pressure of the turning inner wheel, a braking force difference between the left and right wheels is effectively generated, and the turning inner wheel A cornering force can be secured.

  A wheel selection part selects the wheel which becomes an inner side in a turning direction. And the increase in the braking pressure of the selected wheel is limited.

  Specifically, based on the characteristics shown in FIG. 12, the braking pressure Ps ** for starting the pressure increase limitation is determined using the turning state amount Tc. When the turning state amount Tc is equal to or less than the predetermined value Tcv, the pressure increase limitation of the turning inner wheel is not performed. When the turning state amount Tc becomes larger than the predetermined value Tcv, the braking pressure (pressure increase limiting pressure) Ps ** for starting the pressure increase limitation of the turning inner wheel is determined according to the turning state amount Tc.

  The pressure increase restriction pressure (restriction start braking pressure) Ps ** can be set to a different value depending on whether the wheel (selected wheel) subject to pressure increase restriction is the front wheel or the rear wheel. When the selected wheel is a rear wheel, it is more desirable to secure a cornering force. Therefore, the pressure increase limiting pressure Ps ** can be set to a lower value than when the selected wheel is a front wheel. Further, when the vehicle body speed is high, more vehicle stability is desired. Therefore, the pressure increase limiting pressure Ps ** is set according to the vehicle body speed Vx. Specifically, as the vehicle body speed is higher, the pressure increase limiting pressure Ps ** can be set to a lower value.

  Since the braking pressure is a value that changes according to the braking operation amount Bs or the vehicle body deceleration Gx, instead of the pressure increase limiting pressure Ps **, the pressure increase limiting braking operation amount (limit starting braking operation amount) Sbs, Alternatively, the pressure increase limit deceleration (limit start deceleration) Sgx can be calculated.

  The upper limit value Zs ** of the pressure increase gradient (the amount of change in pressure increase) can be determined based on the characteristics shown in FIG. 13 using the turning state amount Tc. The characteristic can be set such that the pressure increase gradient upper limit value Zs ** decreases as the turning state amount Tc increases.

  When the vehicle body speed is high, more vehicle stability is desired. Therefore, the pressure increase gradient upper limit value Zs ** can be set according to the vehicle body speed Vx. For example, the higher the vehicle body speed, the lower the pressure increase gradient upper limit value can be set. Further, when the selected wheel is the rear wheel, it is more desirable to secure the cornering force. Therefore, the pressure increase gradient upper limit value can be set to a lower value than when the selected wheel is the front wheel.

  The pressure increase gradient upper limit value Zs ** is used when controlling the opening / closing time of the pressure increase limiting means (for example, the inlet valve IV **) (so-called pulse pressure increase). The pressure increase gradient upper limit value Zs ** can be set to “0 (maintenance of braking pressure)”. When the pressure increase restricting means is an ON / OFF solenoid valve, pressure fluctuation occurs as the solenoid valve opens and closes. Therefore, when the pressure increase is limited, the braking pressure is maintained by holding the solenoid valve (inlet valve) in the closed position so that kickback to the brake pedal does not occur.

  The pressure increase restriction pressure Ps ** (the pressure increase restriction braking operation amount Sbs or the pressure increase restriction deceleration Sgx) is a threshold value at which the pressure increase restriction is started. For this reason, the control for limiting pressure increase is executed in the upper region than the characteristic shown in FIG. 12 (characteristic indicated by a solid line or a broken line). On the other hand, the pressure increase gradient upper limit value Zs ** determines the amount of pressure increase after the start of pressure increase restriction.

  The pressure increase restriction is performed by a pressure increase restriction means (for example, an inlet valve IV **). When the inlet valve IV ** is an ON / OFF valve, the duty ratio Dt ** for driving the inlet valve is determined based on the pressure increase gradient upper limit value Zs ** based on the characteristics shown in FIG. Here, the duty ratio Dt ** = 1 corresponds to a state where power is always supplied. In this case, the inlet valve is in a closed position, and the braking pressure is maintained at that pressure. The duty ratio Dt ** = 0 corresponds to a non-energized state. In this case, the inlet valve is in the open position. The pressure increase gradient is limited by the duty ratio Dt **. That is, the duty ratio Dt ** is determined based on the pressure increase gradient upper limit value Zs **, and the pressure increase restriction is performed by pressure holding or so-called pulse pressure increase.

  Changes in the ground load due to turning and vehicle deceleration appear as slipperiness of the wheels. Therefore, instead of the turning state amount Tc, the pressure increase restriction can be executed based on a value representing the slipperiness of the turning inner wheel. The value representing the slipperiness of the wheel (hereinafter also referred to as the wheel state quantity Py **) is, for example, the wheel slip speed Sl ** obtained from the difference between the vehicle body speed and the wheel speed. The wheel slip ratio Sr ** divided by can also be used. Further, the degree of difference in wheel slip speed or wheel slip rate (for example, difference, ratio, etc.) between the wheels can be used as the wheel state quantity.

  In addition, the wheel state quantity Py ** using a known road surface μ gradient (for example, JP-A-2001-133390, US6522968) and wheel grip degree (for example, JP-A-2003-31465, US6895317). Can also be calculated. When the wheel state quantity Py ** of the selected wheel (turning inner ring) becomes larger than a predetermined value (when the turning inner wheel becomes slippery), the pressure increase limit of the wheel (start of pressure increase limit and the pressure increase gradient) Limiting or holding pressure) can be performed based on the wheel state quantity Py **.

<Drive means>
The driving means DRa (see FIG. 3) of the pressure adjusting means applies the auxiliary pressure to the pressure generated by the first pressure generating means (master cylinder) to control the wheel cylinder pressure of each wheel, so that the second pressure generating means (Electric motor / pump) and pressure adjusting means (linear pressure regulating valve) of each piping system are driven and controlled. That is, based on the auxiliary pressure target value SP # t calculated in the auxiliary pressure target value calculation, the rotation of the electric motor M and the opening / closing of the linear pressure regulating valve (linear solenoid valve) of each piping system are controlled.

  Based on the auxiliary pressure target value SP # t, the driving means DRa controls the electric motor M to be higher than the pump rotational speed that can supply it. Based on the detection result (for example, master cylinder pressure Pmc) of the detecting means BS and the auxiliary pressure target value SP # t, the pressure target value Ph # t (or the wheel pressure target value Pw ** t) of each piping system is obtained. The current value for driving the linear pressure regulating valve is determined and controlled based on these values. When the pressure sensor PH # (or the pressure sensor P ** of each wheel) is provided in each piping system, the actual pressure (Ph # a or Pw ** a) detected by the pressure sensor is the pressure target. Feedback control is performed so as to match the value. The pressure sensors PH # and P ** can be omitted. In this case, the pressure can be estimated based on the behavior (background) of the wheel speed, the operating state of the valves (linear pressure regulating valve, inlet valve, and outlet valve).

  The drive means DRb controls the inlet valve (normally open valve) IV ** based on the duty ratio Dt **. Specifically, as shown in FIG. 15, the energization time (ON time) in one control cycle is determined based on the duty ratio Dt **. Here, the duty ratio Dt ** = 0 corresponds to a normally non-energized state (OFF state), and the inlet valve is maintained in the open position. Further, the duty ratio Dt ** = 1 corresponds to a constantly energized state (ON state), and the inlet valve is maintained in the closed position state. The energization time (ON time) in one control cycle is controlled based on the duty ratio Dt **, and the increase in braking pressure is limited. This control is generally called pulse boosting.

  Further, the driving means DRb controls the outlet valve (normally closed valve) OV ** to limit the decrease in the braking pressure. When the braking control is finished or when the driver's braking operation is returned, it is necessary to make the braking pressure held by the inlet valve coincide with the pressure of the braking pipe. In this case, when the outlet valve is changed to the open position and the braking pressure is reduced, kickback to the brake pedal BP occurs, so that the state where the outlet valve is held at the closed position is maintained. The brake pressure in the wheel cylinder is matched with the pressure in the brake pipe via a check valve CV ** (see FIG. 2) provided in the inlet valve.

《Action ・ Effect》
Hereinafter, the operation and effect of the present invention will be described. FIG. 16 shows a change in braking pressure when the braking control is performed. The characteristic of the braking pressure Pw ** of the wheel cylinder when the stabilization control is not executed is the characteristic indicated by the broken line. The characteristic of the braking pressure of the wheel connected to the brake pipe whose pressure is increased by the stabilization control is a characteristic (characteristic (1)) increased from the characteristic indicated by the broken line. On the contrary, the characteristic of the braking pressure of the wheel connected to the braking pipe where the pressure is reduced by the stabilization control is a characteristic (characteristic (2)) that is reduced with respect to the characteristic indicated by the broken line.

  FIG. 17 shows a change in braking pressure when the pressure increase restriction and the pressure reduction restriction are performed. When the turning inner wheel or the rear wheel is selected and the braking operation amount reaches a value Sbs for starting the pressure increase restriction determined based on the turning state amount Tc or the like (point Q), the pressure increase restriction means (inlet valve) ) Limits the pressure increase of the selected wheel. At this time, the braking pressure Pw ** of the selected wheel is maintained (represented by the characteristic (3)) or increased with the pressure increase gradient limited (represented by the characteristic (4)). Further, by combining holding and pressure increasing gradient limitation, the braking pressure Pw ** of the selected wheel may be increased by alternately holding and increasing as represented by the characteristic (5). When the pressure increase gradient is limited by opening and closing the inlet valve while performing duty control, kickback to the brake pedal BP occurs. On the other hand, the kickback can be suppressed by maintaining the braking pressure Pw ** as shown in the characteristics (3) and (5).

  When the brake pedal is returned, the inlet valve and the outlet valve of the wheel (selected wheel) on which the pressure increase limitation is executed can be held in the closed position. The return of the brake pedal can be detected from the amount of braking operation. If the inlet valve is changed from the closed position to the open position or the outlet valve is changed from the closed position to the open position when the brake pedal is returned, kickback to the brake pedal BP occurs. Therefore, when the brake pedal is returned, the braking pressure of the selected wheel is matched with the pressure in the piping system via the check valve CV ** provided in the inlet valve.

  For example, when the return operation of the brake pedal BP is performed at the braking operation amount Bs = Bsc, the inlet valve and the outlet valve are held in the closed position, so that the braking pressure is maintained at a pressure corresponding to the point R. Then, after the state in the piping system corresponds to the point S and the pressure becomes the same as that in the braking piping via the check valve CV **, the inlet valve is changed to the open position. The same applies to the case where the pressure is held as the pressure increase limit. After the pressure increase limit is started, the inlet valve is held in the closed position, and at point Q, the pressure is the same as that in the brake pipe via the check valve CV **. After that, the inlet valve is changed to the open position (normal position).

  Based on a turning state amount Tco (for example, lateral acceleration Gyo) at the start of the braking operation, “turning braking” for starting braking during turning and “braking turning” for starting turning after starting braking are discriminated. The second pressure generating means (electric motor / pump) and the pressure adjusting means (linear pressure regulating valve) are controlled based on the respective control characteristics. As a result, the following effects can be obtained.

<Effect in front and rear piping>
(A) When turning braking control is executed The stabilization pressure of the piping system for the front wheels increases. The cornering force of the left and right front wheels is reduced, and the yawing moment inwardly turning is reduced. As a result, the stability of the vehicle is improved. In addition, the stabilization pressure of the rear wheel piping system decreases. The cornering force of the left and right rear wheels increases, and the yawing moment for turning outward increases. As a result, the stability of the vehicle is improved.

(B) When braking and turning control is executed (for example, turning from straight braking)
The stabilization pressure of the front wheel piping system is reduced. The cornering force of the left and right front wheels increases, and the yawing moment inwardly turning increases. As a result, the turning ability of the vehicle is improved. In addition, the stabilization pressure of the rear wheel piping system increases. The cornering force of the left and right rear wheels is reduced, and the generation of a yawing moment that turns outward is suppressed. As a result, the turning ability of the vehicle is improved.

<Effects in diagonal piping>
(C) When turning braking control is executed The stabilization pressure of the braking piping system including the turning outer front wheel increases. An outward yawing moment is generated due to the difference in braking force between the left and right front wheels. Further, the cornering force of the front outer wheel is reduced. As a result, the stability of the vehicle is improved. At this time, if the pressure increase of the rear inner wheel is limited (maintained or pulsed), the stability improvement effect is further improved. In addition, the stabilization pressure of the brake piping system including the turning inner front wheel is reduced. The cornering force of the left and right rear wheels increases, and the yawing moment for turning outward increases. As a result, the stability of the vehicle is improved.

(D) When braking / turning control is executed (for example, turning from straight braking)
The stabilization pressure of the brake piping system including the turning outer front wheel is reduced. An inward yawing moment is generated due to the difference in braking force between the left and right front wheels. Furthermore, the cornering force of the front outer wheel is increased. As a result, the turning ability of the vehicle is improved. In addition, the stabilization pressure of the brake piping system including the turning inner front wheel increases. The cornering force of the rear outer wheel of the turning is reduced, and the generation of the yawing moment outward of the turning is suppressed. As a result, the turning ability of the vehicle is improved.

  Next, the operation of the turning braking control will be described with reference to FIG. FIG. 18 is a time chart illustrating changes in the turning state amount, the braking operation amount, and the braking pressure when the braking operation is performed during the turning. A one-dot chain line indicates a change in braking pressure when the braking control is not executed.

  When the vehicle is making a turning motion, the braking operation is started at time t1, the braking operation is kept constant from time t3, and the return operation is started at time t6. The turning state amount at the start of braking is equal to or greater than a predetermined value, and the selection means selects turning braking control. At time t2, the turning brake control start condition is satisfied, and the stabilization pressure is output. For this reason, in the case of front and rear piping, the braking pressure of the system including the front wheels, and in the diagonal piping, the braking pressure of the system including the turning outer front wheels is increased. In addition, in the case of front and rear piping, the braking pressure of the system including the rear wheels is reduced, and in the case of diagonal piping, the braking pressure of the system including the front inner wheels is reduced. In this case, the stability of the vehicle is improved for the reason described above.

  Next, the operation of the brake turning control will be described with reference to FIG. FIG. 19 is a time chart showing changes in a turning state amount, a braking operation amount, and a braking pressure when a turning operation (steering operation) is performed during braking. A one-dot chain line indicates a change in braking pressure when the braking control is not executed.

  At time u1, the braking operation is started, and the vehicle starts to decelerate. At time u3, the turning operation is started. The turning state amount at the start of braking is less than a predetermined value, and the selection means selects braking turning control. At time u4, the start condition of the brake turning control is established, and the stabilization pressure is output. For this reason, in the case of front and rear piping, the braking pressure of the system including the rear wheels, and in the diagonal piping, the braking pressure of the system including the turning inner front wheels is increased. In addition, the braking pressure of the system including the front wheels is reduced in the case of front and rear piping, and the braking pressure of the system including the front outer wheels in the diagonal piping is reduced. In this case, the turning ability of the vehicle is improved for the reason described above.

  As shown by a broken line in FIG. 19, the braking / turning control can be ended based on a time change amount dTc (for example, a value related to the steering wheel operation angular velocity dθsw) of the turning state amount. The driver desires the turning ability of the vehicle when the steering wheel is moved, that is, when the steering wheel operating angular velocity is generated. Therefore, when the driver holds the steering wheel, the execution of the brake turning control can be terminated.

  For example, in FIG. 19, the braking and turning control ends at a time u6 when a predetermined time has elapsed from the time u5 when the time change amount dTc becomes “0”. As a result, the braking pressure returns to the non-controlling pressure. In this case, the braking pressure can be gradually restored toward the non-controlling pressure without rapidly changing.

<< Other Examples >>
As mentioned above, while the stabilization pressure with respect to one brake piping was increased and the stabilization pressure with respect to the other brake piping was reduced, either one can be abbreviate | omitted. Since the vehicle behavior is determined by the balance (balance) of the force generated by the tire, the vehicle behavior control may be achieved by increasing or decreasing the stabilization pressure of at least one of the brake pipes.

  In addition, the mode in which the adjustment of the stabilization pressure is achieved by multiplying the stabilization base pressure by the correction coefficient has been described. However, the adjustment of the stabilization pressure has a correction value having a pressure dimension in the stabilization base pressure. It is good also as an aspect achieved by adding.

  As described above, in order to perform the turning braking control and the braking turning control, the stabilization pressure SP is obtained by multiplying the stabilization basic pressure SA # o by the coefficient (Kt #, Ks #, or “0 (prohibition of braking control)”). The mode of calculating #s and adding the stabilization pressure SP # s to the assisting pressure SP # o to calculate the auxiliary pressure target value SP # t has been described. However, the assisting pressure SP # o is directly multiplied by a coefficient. Thus, a mode in which the auxiliary pressure target value SP # t is calculated may be employed.

  In this case, the stabilization pressure SP # s and the stabilization basic pressure SA # o are omitted. The coefficient Ku # of the turning braking control is set with a characteristic obtained by replacing “0” of the Y axis with “1” in the characteristic (first characteristic) shown in FIG. The coefficient Kv # of the brake turning control is set with a characteristic obtained by replacing “0” of the Y axis with “1” in the characteristic (second characteristic) shown in FIG. The final auxiliary pressure target value SP # t is calculated by multiplying the assisting pressure SP # o by a coefficient (Ku #, Kv #, or “1 (prohibition of braking control)”).

It is a figure showing the whole brake control device composition for vehicles concerning an embodiment of the present invention. It is the figure which showed the detail of the brake fluid pressure circuit in the whole structure shown in FIG. It is a functional block diagram when the apparatus shown in FIG. 1 performs braking control. It is the graph which showed the table which prescribes | regulates the relationship between the amount of braking operation, and assistance pressure which the apparatus shown in FIG. 1 refers in the case of front and back piping. FIG. 6 is a graph showing another table that defines the relationship between the braking operation amount and the assist pressure, which is referred to by the apparatus shown in FIG. 1 in the case of front and rear piping. It is the graph which showed the table which prescribes | regulates the relationship between the amount of braking operation, and assistance pressure which the apparatus shown in FIG. 1 refers in the case of diagonal piping. It is the graph which showed the table which prescribes | regulates the relationship between the amount of braking operation, and assistance pressure in the case of providing the vacuum booster which the apparatus shown in FIG. 1 refers. It is a functional block diagram of the stabilization pressure calculating part shown in FIG. It is the graph which showed the table which prescribes | regulates the relationship between the braking operation amount and the stabilization basic pressure which the apparatus shown in FIG. 1 refers. It is the graph which showed the table which prescribes | regulates the relationship between a turning state quantity and a turning braking coefficient which the apparatus shown in FIG. 1 refers. It is the graph which showed the table which prescribes | regulates the relationship between the turning state quantity and a braking turning coefficient which the apparatus shown in FIG. 1 refers. It is the graph which showed the table which prescribes | regulates the relationship between the turning state quantity and the pressure increase limitation pressure which the apparatus shown in FIG. 1 refers. It is the graph which showed the table which prescribes | regulates the relationship between the turning state quantity and the pressure increase gradient upper limit which the apparatus shown in FIG. 1 refers. It is the graph which showed the table which prescribes | regulates the relationship between the pressure increase gradient upper limit and the duty ratio of an inlet valve drive current which the apparatus shown in FIG. 1 refers. It is a figure for demonstrating the drive pattern of the inlet valve by which duty control is carried out. It is a figure for demonstrating the range of the braking pressure which can be adjusted with a stabilization pressure. It is the graph which showed the example of the change of the braking pressure of the selection wheel when pressure increase restriction is performed by the device shown in FIG. 3 is a time chart showing an example of a change pattern of each physical quantity when turning braking control is executed by the apparatus shown in FIG. 1. 3 is a time chart showing an example of a change pattern of each physical quantity when braking and turning control is executed by the apparatus shown in FIG. 1. It is a figure for demonstrating the difference in the vehicle behavior at the time of turning braking and braking.

Explanation of symbols

  MC ... Master cylinder, VB ... Vacuum booster, HP # ... Pump, M ... Motor, PM # ... Master cylinder pressure sensor, LV # ... Linear solenoid valve, WC ** ... Wheel cylinder, IV ** ... Inlet valve, OV * *… Outlet valve, CV **… Check valve

Claims (8)

Four wheel braking devices that respectively apply braking torque corresponding to the braking hydraulic pressure supplied to the wheel cylinders of the four front, rear, left, and right wheels of the vehicle to the corresponding wheels;
A first hydraulic pressure generating device having two hydraulic pressure generating chambers each generating a hydraulic pressure amount corresponding to a braking operation amount by a driver of the vehicle;
A first hydraulically connecting one of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right front wheels or two corresponding to the left front wheel and the right rear wheel. Hydraulic piping,
A second hydraulically connecting the other of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right rear wheels or two corresponding to the right front wheel and the left rear wheel. Hydraulic piping of
A power-driven second hydraulic pressure generator for generating an assisting hydraulic pressure to be added to the hydraulic pressure amount generated by the first hydraulic pressure generator in each of the first and second hydraulic pipes; ,
Braking operation amount detection means for detecting the braking operation amount;
A turning state amount detecting means for detecting a turning state amount representing the turning motion of the vehicle;
An assisting fluid that determines a first assisting hydraulic pressure reference amount in the first hydraulic piping and a second assisting hydraulic pressure reference amount in the second hydraulic piping based only on the detected braking operation amount. Pressure reference amount determining means;
A first state in which the braking start turning state amount detected as the turning state amount at the start of the braking operation by the driver is greater than or equal to a first predetermined value , and the braking start turning state amount is less than the first predetermined value. a state determination unit and the second state, the selectively detected is,
When the first state is detected, based on the detected turning state amount, the two wheel braking devices or turning outer front wheels corresponding to the left and right front wheels of the first and second hydraulic pipes. And the first assist hydraulic pressure target amount in one hydraulic pipe connected to the two wheel braking devices corresponding to the turning inner rear wheel, out of the determined first and second assist hydraulic pressure reference amounts At the same time, a value within the range of one assist hydraulic pressure reference amount corresponding to the one hydraulic pipe is determined, and at the same time , the second hydraulic pipe in the other hydraulic pipe of the first and second hydraulic pipes When the assisting fluid pressure target amount is determined to be a value within the range of the other assisting fluid pressure reference amount of the determined first and second assisting fluid pressure reference amounts, and the second state is detected The first assist hydraulic pressure target amount is determined based on the detected turning state amount. And determines the value of the assisting pressure reference amount within the range of, at the same time, assisting pressure target for determining said second assisting pressure target amount to a value in the range of more than assisting pressure reference amount of the other A quantity determining means;
Pressure adjusting means for adjusting the assist hydraulic pressure in each of the one and the other hydraulic pipes to match the determined first and second assist hydraulic pressure target amounts, respectively;
A vehicle braking control apparatus comprising: The vehicle brake control device according to claim 1,
The assist hydraulic pressure target amount determining means includes:
Based on the detected braking operation amount, the stabilized basic hydraulic pressure amount in the first and second hydraulic pipes is determined to be zero when the detected braking operation amount is less than a predetermined operation amount greater than zero. And a stabilizing basic hydraulic pressure amount determining means for determining a value larger than zero when the braking operation amount is larger than the predetermined operation amount,
When the first state is detected, the first stabilized hydraulic pressure amount in the one hydraulic pipe is obtained based on the detected turning state amount to the determined stabilized basic hydraulic pressure amount. A value obtained by multiplying a coefficient of zero or more is determined, and a second stabilized hydraulic pressure amount in the other hydraulic pipe is determined based on the detected turning state to the determined stabilized basic hydraulic pressure amount. When the second state is detected, the first stabilized hydraulic pressure amount is added to the determined stabilized basic hydraulic pressure amount when the second state is detected. A value obtained by multiplying a coefficient of zero or less obtained based on the detected turning state amount is determined, and the second stabilized hydraulic pressure amount is detected as the determined stabilized basic hydraulic pressure amount. Multiply by a coefficient of zero or more obtained based on the amount of turning state A stabilizing solution pressure amount determining means for determining the value to be,
With
The assist hydraulic pressure target amount determining means includes:
The first assist hydraulic pressure target amount is determined to be a value obtained by adding the first stabilizing hydraulic pressure amount to the one assist hydraulic pressure reference amount, and the second assist hydraulic pressure target amount is set as the second assist hydraulic pressure target amount. The vehicle braking control device is configured to determine a value obtained by adding the second stabilizing hydraulic pressure amount to the other assist hydraulic pressure reference amount. Four wheel braking devices that respectively apply braking torque corresponding to the braking hydraulic pressure supplied to the wheel cylinders of the four front, rear, left, and right wheels of the vehicle to the corresponding wheels;
A first hydraulic pressure generating device having two hydraulic pressure generating chambers each generating a hydraulic pressure amount corresponding to a braking operation amount by a driver of the vehicle;
A first hydraulically connecting one of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right front wheels or two corresponding to the left front wheel and the right rear wheel. Hydraulic piping,
A second hydraulically connecting the other of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right rear wheels or two corresponding to the right front wheel and the left rear wheel. Hydraulic piping of
A power-driven second hydraulic pressure generator for generating an assisting hydraulic pressure to be added to the hydraulic pressure amount generated by the first hydraulic pressure generator in each of the first and second hydraulic pipes; ,
Braking operation amount detection means for detecting the braking operation amount;
A turning state amount detecting means for detecting a turning state amount representing the turning motion of the vehicle;
An assisting fluid that determines a first assisting hydraulic pressure reference amount in the first hydraulic piping and a second assisting hydraulic pressure reference amount in the second hydraulic piping based only on the detected braking operation amount. Pressure reference amount determining means;
A first state in which the braking start turning state amount detected as the turning state amount at the start of the braking operation by the driver is greater than or equal to a first predetermined value , and the braking start turning state amount is greater than the first predetermined value. and a second state is smaller than the second predetermined value or more in a by the first predetermined value, and a third state wherein the brake start turning state quantity is less than the second predetermined value, to selectively detect State discrimination means;
When the first state is detected, based on the detected turning state amount, the two wheel braking devices or turning outer front wheels corresponding to the left and right front wheels of the first and second hydraulic pipes. And the first assist hydraulic pressure target amount in one hydraulic pipe connected to the two wheel braking devices corresponding to the turning inner rear wheel, out of the determined first and second assist hydraulic pressure reference amounts At the same time, a value within the range of one assist hydraulic pressure reference amount corresponding to the one hydraulic pipe is determined, and at the same time , the second hydraulic pipe in the other hydraulic pipe of the first and second hydraulic pipes When the assisting fluid pressure target amount is determined to be a value within the range of the other assisting fluid pressure reference amount of the determined first and second assisting fluid pressure reference amounts, and the second state is detected The first and second assist hydraulic pressure target amounts are equal to the other assist hydraulic pressure reference amount. Determining each value, when said third state is detected, based on the detected turning state quantity, the first assisting pressure target amount within the following ranges assisting pressure reference amount of the one And at the same time, an assisting hydraulic pressure target amount determining means for determining the second assisting hydraulic pressure target amount to a value within the range of the other assisting hydraulic pressure reference amount or more,
Pressure adjusting means for adjusting the assist hydraulic pressure in each of the one and the other hydraulic pipes to match the determined first and second assist hydraulic pressure target amounts, respectively;
A vehicle braking control apparatus comprising: The vehicle brake control device according to claim 3, wherein
The assist hydraulic pressure target amount determining means includes:
Based on the detected braking operation amount, the stabilized basic hydraulic pressure amount in the first and second hydraulic pipes is determined to be zero when the detected braking operation amount is less than a predetermined operation amount greater than zero. And a stabilizing basic hydraulic pressure amount determining means for determining a value larger than zero when the braking operation amount is larger than the predetermined operation amount,
When the first state is detected, the first stabilized hydraulic pressure amount in the one hydraulic pipe is obtained based on the detected turning state amount to the determined stabilized basic hydraulic pressure amount. A value obtained by multiplying a coefficient of zero or more is determined, and a second stabilized hydraulic pressure amount in the other hydraulic pipe is determined based on the detected turning state to the determined stabilized basic hydraulic pressure amount. When the second state is detected, the first and second stabilizing hydraulic pressure amounts are determined to be zero when the second state is detected. When a state is detected, a value obtained by multiplying the first stabilization hydraulic pressure amount by the coefficient of zero or less obtained on the basis of the detected turning state amount to the determined stabilization basic hydraulic pressure amount And determining the second stabilizing hydraulic pressure amount to the determined stabilization A stabilizing solution pressure amount determining means for determining a value obtained by multiplying the zero or more coefficients obtained on the basis of the detected turning state quantity cornerstone liquid pressure amount,
With
The assist hydraulic pressure target amount determining means includes:
The first assist hydraulic pressure target amount is determined to be a value obtained by adding the first stabilizing hydraulic pressure amount to the one assist hydraulic pressure reference amount, and the second assist hydraulic pressure target amount is set as the second assist hydraulic pressure target amount. The vehicle braking control device is configured to determine a value obtained by adding the second stabilizing hydraulic pressure amount to the other assist hydraulic pressure reference amount. Four wheel braking devices that respectively apply braking torque corresponding to the braking hydraulic pressure supplied to the wheel cylinders of the four front, rear, left, and right wheels of the vehicle to the corresponding wheels;
A first hydraulic pressure generating device having two hydraulic pressure generating chambers each generating a hydraulic pressure amount corresponding to a braking operation amount by a driver of the vehicle;
A first hydraulically connecting one of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right front wheels or two corresponding to the left front wheel and the right rear wheel. Hydraulic piping,
A second hydraulically connecting the other of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right rear wheels or two corresponding to the right front wheel and the left rear wheel. Hydraulic piping of
A power-driven second hydraulic pressure generator for generating an assisting hydraulic pressure to be added to the hydraulic pressure amount generated by the first hydraulic pressure generator in each of the first and second hydraulic pipes; ,
Braking operation amount detection means for detecting the braking operation amount;
A turning state amount detecting means for detecting a turning state amount representing the turning motion of the vehicle;
An assisting fluid that determines a first assisting hydraulic pressure reference amount in the first hydraulic piping and a second assisting hydraulic pressure reference amount in the second hydraulic piping based only on the detected braking operation amount. Pressure reference amount determining means;
A first state in which the braking start turning state amount detected as the turning state amount at the start of the braking operation by the driver is greater than or equal to a first predetermined value , and the braking start turning state amount is less than the first predetermined value. a state determination unit and the second state, the selectively detected is,
When the first state is detected, based on the detected turning state amount, the two wheel braking devices or turning outer front wheels corresponding to the left and right front wheels of the first and second hydraulic pipes. And the first assist hydraulic pressure target amount in one hydraulic pipe connected to the two wheel braking devices corresponding to the turning inner rear wheel, out of the determined first and second assist hydraulic pressure reference amounts At the same time, a value within the range of one assist hydraulic pressure reference amount corresponding to the one hydraulic pipe is determined, and at the same time , the second hydraulic pipe in the other hydraulic pipe of the first and second hydraulic pipes When the assisting fluid pressure target amount is determined to be a value within the range of the other assisting fluid pressure reference amount of the determined first and second assisting fluid pressure reference amounts, and the second state is detected The first and second assist hydraulic pressure target amounts are equal to the other assist hydraulic pressure reference amount. And assisting pressure target amount determining means for determining the respective values,
Pressure adjusting means for adjusting the assist hydraulic pressure in each of the one and the other hydraulic pipes to match the determined first and second assist hydraulic pressure target amounts, respectively;
A vehicle braking control apparatus comprising: The vehicle brake control device according to claim 5, wherein
The assist hydraulic pressure target amount determining means includes:
Based on the detected braking operation amount, the stabilized basic hydraulic pressure amount in the first and second hydraulic pipes is determined to be zero when the detected braking operation amount is less than a predetermined operation amount greater than zero. And a stabilizing basic hydraulic pressure amount determining means for determining a value larger than zero when the braking operation amount is larger than the predetermined operation amount,
When the first state is detected, the first stabilized hydraulic pressure amount in the one hydraulic pipe is obtained based on the detected turning state amount to the determined stabilized basic hydraulic pressure amount. A value obtained by multiplying a coefficient of zero or more is determined, and a second stabilized hydraulic pressure amount in the other hydraulic pipe is determined based on the detected turning state to the determined stabilized basic hydraulic pressure amount. A value obtained by multiplying a coefficient less than or equal to zero obtained in this manner, and when the second state is detected, the first and second stabilization fluid pressure amounts are determined to be zero. A determination means;
With
The assist hydraulic pressure target amount determining means includes:
The first assist hydraulic pressure target amount is determined to be a value obtained by adding the first stabilizing hydraulic pressure amount to the one assist hydraulic pressure reference amount, and the second assist hydraulic pressure target amount is set as the second assist hydraulic pressure target amount. The vehicle braking control device is configured to determine a value obtained by adding the second stabilizing hydraulic pressure amount to the other assist hydraulic pressure reference amount. Four wheel braking devices that respectively apply braking torque corresponding to the braking hydraulic pressure supplied to the wheel cylinders of the four front, rear, left, and right wheels of the vehicle to the corresponding wheels;
A first hydraulic pressure generating device having two hydraulic pressure generating chambers each generating a hydraulic pressure amount corresponding to a braking operation amount by a driver of the vehicle;
A first hydraulically connecting one of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right front wheels or two corresponding to the left front wheel and the right rear wheel. Hydraulic piping,
A second hydraulically connecting the other of the two hydraulic pressure generating chambers to two of the four wheel braking devices corresponding to the left and right rear wheels or two corresponding to the right front wheel and the left rear wheel. Hydraulic piping of
A power-driven second hydraulic pressure generator for generating an assisting hydraulic pressure to be added to the hydraulic pressure amount generated by the first hydraulic pressure generator in each of the first and second hydraulic pipes; ,
Braking operation amount detection means for detecting the braking operation amount;
A turning state amount detecting means for detecting a turning state amount representing the turning motion of the vehicle;
An assisting fluid that determines a first assisting hydraulic pressure reference amount in the first hydraulic piping and a second assisting hydraulic pressure reference amount in the second hydraulic piping based only on the detected braking operation amount. Pressure reference amount determining means;
A first state in which the braking start turning state amount detected as the turning state amount at the start of the braking operation by the driver is greater than or equal to a first predetermined value , and the braking start turning state amount is less than the first predetermined value. a state determination unit and the second state, the selectively detected is,
When the first state is detected, based on the detected turning state amount, the two wheel braking devices or turning outer front wheels corresponding to the left and right front wheels of the first and second hydraulic pipes. And the first assist hydraulic pressure target amount in one hydraulic pipe connected to the two wheel braking devices corresponding to the turning inner rear wheel, out of the determined first and second assist hydraulic pressure reference amounts At the same time, it is determined to be equal to one assist hydraulic pressure reference amount corresponding to the one hydraulic pipe, and at the same time, the second assist hydraulic pressure in the other hydraulic pipe among the first and second hydraulic pipes. When the target amount is determined to be equal to the other assist hydraulic pressure reference amount among the determined first and second assist hydraulic pressure reference amounts, and the second state is detected, the detected turning Based on the state quantity, the first assist hydraulic pressure target quantity is set to the one assist hydraulic pressure. And determines a value in the range below quasi amount, at the same time, the assisting pressure target amount determining means for determining the second assisting pressure target amount to a value in the range of more than assisting pressure reference amount of the other ,
Pressure adjusting means for adjusting the assist hydraulic pressure in each of the one and the other hydraulic pipes to match the determined first and second assist hydraulic pressure target amounts, respectively;
A vehicle braking control apparatus comprising: The vehicle brake control device according to claim 7,
The assist hydraulic pressure target amount determining means includes:
Based on the detected braking operation amount, the stabilized basic hydraulic pressure amount in the first and second hydraulic pipes is determined to be zero when the detected braking operation amount is less than a predetermined operation amount greater than zero. And a stabilizing basic hydraulic pressure amount determining means for determining a value larger than zero when the braking operation amount is larger than the predetermined operation amount,
When the first state is detected, the first stabilizing hydraulic pressure amount in the one hydraulic piping and the second stabilizing hydraulic pressure amount in the other hydraulic piping are determined to be zero, When the state of 2 is detected, the first stabilization hydraulic pressure amount is obtained by multiplying the determined stabilization basic hydraulic pressure amount by a coefficient of zero or less obtained based on the detected turning state amount. And a value obtained by multiplying the second stabilized hydraulic pressure amount by the coefficient of zero or more obtained based on the detected turning state to the second stabilized hydraulic pressure amount. A stabilizing hydraulic pressure determining means for determining;
With
The assist hydraulic pressure target amount determining means includes:
The first assist hydraulic pressure target amount is determined to be a value obtained by adding the first stabilizing hydraulic pressure amount to the one assist hydraulic pressure reference amount, and the second assist hydraulic pressure target amount is set as the second assist hydraulic pressure target amount. The vehicle braking control device is configured to determine a value obtained by adding the second stabilizing hydraulic pressure amount to the other assist hydraulic pressure reference amount.

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