JP2016055739A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake control device which can avoid a phenomenon in which a pedal stroke cannot be secured, and can provide excellent pedal feeling.SOLUTION: A target wheel cylinder fluid pressure is calculated on the basis of a stroke corresponding target wheel cylinder fluid pressure which is set according to an operation stroke of a brake pedal by a driver, and a master cylinder fluid pressure corresponding target wheel cylinder fluid pressure which is set according to a master cylinder fluid pressure. A brake fluid is suctioned by a pump from a master cylinder. A wheel cylinder fluid pressure is increased to reach the target wheel cylinder fluid pressure.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a brake control device.

  Patent Document 1 discloses a brake control device that increases the wheel cylinder hydraulic pressure by sucking brake fluid in a master cylinder or a reservoir with a hydraulic pressure source and discharging the brake fluid to the wheel cylinder.

Japanese Patent Laid-Open No. 10-329678

However, if the degree of increase in the wheel cylinder fluid pressure relative to the amount of brake fluid supplied to the wheel cylinder (hereinafter referred to as brake rigidity) is high, the amount of brake fluid pumped from the master cylinder decreases and the brake pedal stroke There is a risk that a boarding phenomenon will occur.
An object of the present invention is to provide a brake control device that can avoid a stepping phenomenon and achieve a good pedal feeling.

  In the present invention, based on the stroke-corresponding target wheel cylinder hydraulic pressure set according to the operation stroke of the brake pedal of the driver and the master cylinder hydraulic pressure-corresponding target wheel cylinder hydraulic pressure set according to the master cylinder hydraulic pressure. The target wheel cylinder hydraulic pressure was calculated, the brake fluid was sucked from the master cylinder by the pump, and the wheel cylinder hydraulic pressure was increased so as to be the target foil cylinder hydraulic pressure.

  Therefore, a good pedal feeling can be obtained.

It is a block diagram of the brake control apparatus of Example 1. It is a control block diagram showing the concept of the target wheel cylinder hydraulic pressure setting of this invention. FIG. 3 is a control block diagram illustrating a control configuration of brake assist control according to the first embodiment. It is a block diagram of the brake control apparatus of Example 2. It is a block diagram of the brake control apparatus of Example 3. FIG. 10 is a control block diagram illustrating a control configuration of brake assist control according to a fourth embodiment.

[Example 1]
FIG. 1 is a configuration diagram of the brake control device according to the first embodiment. The hydraulic control unit HU adjusts the braking force applied to each wheel of the vehicle. Based on commands from the brake control unit BCU, the wheel cylinder W / C (RL) for the left rear wheel and the wheel cylinder for the right front wheel Increase / decrease or maintain the hydraulic pressures of W / C (FR), left front wheel wheel cylinder W / C (FL), and right rear wheel wheel cylinder W / C (RR).
The hydraulic control unit HU has a piping structure called X piping, which is composed of two systems, a P system and an S system. By adopting X piping, even if one piping system fails, the other piping system can be used to generate half of the braking force during normal operation. In addition, P attached to the end of the code | symbol of each site | part described in FIG. 1 shows P system, S shows S system, and RL, FR, FL, RR is a left rear wheel, a right front wheel, a left front wheel, and a right rear. Indicates that it corresponds to a ring. In the following description, the description of P, S or RL, FR, FL, RR is omitted when the P, S system or each wheel is not distinguished.

The hydraulic control unit HU according to the first embodiment uses a closed hydraulic circuit. Here, the “closed hydraulic circuit” refers to a hydraulic circuit that returns the brake fluid supplied to the wheel cylinder W / C to the reservoir tank RSV via the master cylinder M / C. By the way, the hydraulic circuit that can return the brake fluid supplied to the wheel cylinder W / C directly to the reservoir tank RSV without passing through the master cylinder M / C is called “Open hydraulic circuit”. That's it.
The brake pedal BP is connected to the master cylinder M / C via the input rod IR. The pedal depression force input to the brake pedal BP is boosted by the brake booster BB. The brake booster BB has a negative pressure sensor 18 for detecting the booster negative pressure. The master cylinder M / C generates the brake fluid pressure boosted by the brake booster BB. The input rod IR has a stroke sensor 17 that detects the stroke amount of the brake pedal BP.
The wheel cylinder W / C (RL) for the left rear wheel RL and the wheel cylinder W / C (FR) for the right front wheel FR are connected to the S system, and the wheel cylinder W / C (for the left front wheel FL is connected to the P system. FL) and the wheel cylinder W / C (RR) of the right rear wheel RR are connected. The P system and S system are provided with pumps PP and PS (hereinafter sometimes collectively referred to as pumps P). The pumps PP and PS are driven by one motor M. The motor M controls the motor rotation speed according to a desired drive amount. The pumps PP and PS are plunger pumps. In addition, it may replace with a plunger pump and may employ | adopt a gear pump and is not specifically limited.

Master cylinder M / C and wheel cylinder W / C are connected by pipe line 1 and pipe line 2. The pipeline 2S is branched into pipelines 2RL and 2FR, the pipeline 2RL is connected to the wheel cylinder W / C (RL), and the pipeline 2FR is connected to the wheel cylinder W / C (FR). The pipe line 2P branches into pipe lines 2FL and 2RR, the pipe line 2FL is connected to the wheel cylinder W / C (FL), and the pipe line 2RR is connected to the wheel cylinder W / C (RR).
On the pipeline 1, a gate-out valve 3 which is a normally open type proportional control valve is provided. A master cylinder hydraulic pressure sensor 40 for detecting the master cylinder hydraulic pressure is provided at a position closer to the master cylinder than the gate-out valve 3P of the pipe line 1P of the P system. On the pipeline 1, a pipeline 4 is provided in parallel with the gate-out valve 3. A check valve 5 is provided on the pipeline 4. The check valve 5 allows the flow of brake fluid from the master cylinder M / C to the wheel cylinder W / C and prohibits the flow in the opposite direction.
A solenoid-in valve 6 which is a normally open proportional control valve corresponding to each wheel cylinder W / C is provided on the pipe line 2. On the pipe 2, a pipe 7 is provided in parallel with the solenoid-in valve 6. A check valve 8 is provided on the pipeline 7. The check valve 8 allows the brake fluid to flow in the direction from the wheel cylinder W / C toward the master cylinder M / C, and prohibits the flow in the opposite direction.

The discharge side of the pump P and the pipe line 2 are connected by a pipe line 9. A discharge valve 10 is provided on the pipeline 9. The discharge valve 10 allows the flow of brake fluid in the direction from the pump P toward the pipe 2 and prohibits the flow in the opposite direction.
A position on the master cylinder side with respect to the gate-out valve 3 of the pipe line 1 and the suction side of the pump P are connected by a pipe line 11 and a pipe line 12. A pressure regulating reservoir 13 is provided between the pipe line 11 and the pipe line 12.
A position on the wheel cylinder side of the solenoid valve 6 in the pipeline 2 and the pressure adjusting reservoir 13 are connected by a pipeline 14. The pipeline 14S branches to pipelines 14RL and 14FR, and the pipeline 14P branches to pipelines 14FL and 14RR and is connected to the corresponding wheel cylinder W / C.
A solenoid-out valve 15 that is a normally closed solenoid valve is provided on the pipeline 14.
The pressure adjustment reservoir 13 includes a pressure-sensitive check valve 16. The check valve 16 applies a high pressure to the suction side of the pump P by prohibiting the flow of brake fluid into the pressure regulating reservoir 13 when the pressure in the pipe line 11 exceeds a predetermined pressure. To prevent. The check valve 16 opens regardless of the pressure in the pipe line 11 when the pump P is activated and the pressure in the pipe line 12 becomes low. Allow inflow.

[Brake control]
The brake control unit BCU performs anti-lock brake (ABS) control as brake control. When ABS control detects that a wheel has become locked during brake operation by the driver, the wheel cylinder hydraulic pressure is reduced, held, and increased in order to generate the maximum braking force while preventing the wheel from locking. It is a control that repeats the pressure. At the time of ABS pressure reduction control, the solenoid cylinder valve 6 is closed and the solenoid valve 15 is opened from the state shown in FIG. 1 to release the brake fluid of the wheel cylinder W / C to the pressure regulating reservoir 13 to reduce the wheel cylinder fluid pressure. In the ABS holding control, the wheel cylinder hydraulic pressure is held by closing both the solenoid-in valve 6 and the solenoid-out valve 15. In ABS pressure increase control, the solenoid in valve 6 is controlled in the opening direction and the solenoid out valve 15 is closed, and the brake fluid is supplied from the master cylinder M / C to the wheel cylinder W / C to increase the wheel cylinder hydraulic pressure. .
Further, when the hydraulic pressure control unit HU of the first embodiment detects that an oversteer tendency or an understeer tendency has become strong during vehicle turning by operating each valve and the pump P as brake control, Vehicle behavior stabilization control that controls the wheel cylinder hydraulic pressure to stabilize the vehicle behavior, and the wheel cylinder W / C generates pressure higher than the pressure that is actually generated in the master cylinder M / C when the driver brakes Automatic brake control such as control for automatically generating braking force according to the relative relationship with the preceding vehicle can be performed by brake assist control and auto cruise control.

  In each brake control, the brake control unit BCU receives signals from other in-vehicle sensors (wheel speed sensor, steering angle sensor, yaw rate sensor, lateral acceleration sensor, etc.) in addition to the master cylinder hydraulic pressure sensor 40 and the stroke sensor 17. Based on this, the target hydraulic pressure of the wheel cylinder W / C is generated. Then, each valve and the motor M of the hydraulic pressure control unit HU are driven so that the wheel cylinder hydraulic pressure matches the target hydraulic pressure. The motor M, the gate-out valve 3 and the solenoid-in valve 6 are PWM controlled at a constant control cycle. The solenoid out valve 15 is ON / OFF controlled. The brake control unit BCU includes a motor drive unit 20 that drives the motor M.

(About brake assist control)
Next, the brake assist control of the first embodiment will be described. In recent years, the negative pressure of the engine has been decreasing from the viewpoint of improving fuel efficiency. Therefore, it is assumed that the boost function by the brake booster BB cannot be sufficiently secured. Therefore, a brake assist control that drives the pump P in accordance with the driver's brake pedal operation state and compensates for a decrease in the boosting function by the brake booster BB is expected. In the brake assist control, the gate-out valve 3 is closed (or closed by electromagnetic force that generates the required differential pressure by balance control, and controlled to overcome the electromagnetic force and open when the required differential pressure is exceeded. The brake fluid in the master cylinder M / C is pumped up by the pump P and supplied to the wheel cylinder W / C. This ensures a stroke when the driver depresses the brake pedal and assists the brake pedal operating force. When the pump P is activated, the pressure in the pipe 12 decreases, so that the check valve 16 automatically opens regardless of the pressure in the pipe 11, and the master cylinder M passes through the pressure regulating reservoir 13. Brake fluid flows from / C to the suction side of pump P. As a result, during brake assist control, the brake fluid moves from the master cylinder M / C side to the wheel cylinder W / C side.

  Here, it is assumed that the target wheel cylinder hydraulic pressure is calculated according to the stroke amount of the brake pedal and the pump P is operated. When a target wheel cylinder corresponding to a certain stroke amount is set and the pump P is driven, it is possible to generate a wheel cylinder pressure corresponding to the stroke amount. However, the brake rigidity between the hydraulic control unit HU and the wheel cylinder W / C is not constant due to manufacturing variations and aging. For example, when the brake rigidity is low, it is necessary to pump a lot of brake fluid from the master cylinder M / C in order to achieve the target wheel cylinder fluid pressure. In this case, the brake pedal BP is sucked in and an excessive stroke may occur, and the driver's intention to brake cannot be accurately reflected, and there is a concern that the pedal feeling may deteriorate. On the other hand, when the brake rigidity is high, less brake fluid is pumped from the master cylinder M / C to achieve the target wheel cylinder hydraulic pressure. In this case, the brake fluid in the master cylinder M / C does not decrease, and there is a risk of a plate stepping phenomenon in which the stroke of the brake pedal BP cannot be secured, and the driver's braking intention cannot be accurately reflected. There is concern about deterioration.

  Therefore, in the first embodiment, in setting the target wheel cylinder hydraulic pressure, in addition to the stroke corresponding target wheel cylinder hydraulic pressure P1 * based on the stroke amount STR of the brake pedal, the master cylinder hydraulic pressure corresponding to the master cylinder hydraulic pressure Pmc is supported. The target wheel cylinder hydraulic pressure P2 * is calculated, and the final target wheel cylinder hydraulic pressure P * is calculated based on the stroke corresponding target wheel cylinder hydraulic pressure P1 * and the master cylinder compatible target wheel cylinder hydraulic pressure P2 *. did.

  FIG. 2 is a control block diagram showing the concept of target wheel cylinder hydraulic pressure setting according to the present invention. The stroke-corresponding target wheel cylinder hydraulic pressure calculation unit 101 calculates a stroke-corresponding target wheel cylinder hydraulic pressure P1 * corresponding to the stroke amount STR detected by the stroke sensor 17. The master cylinder hydraulic pressure target wheel cylinder hydraulic pressure calculation unit 102 multiplies the master cylinder hydraulic pressure Pmc detected by the master cylinder hydraulic pressure sensor 40 by the conversion coefficient K to obtain a master cylinder hydraulic pressure target foil cylinder hydraulic pressure P2 *. Is calculated. The target wheel cylinder hydraulic pressure calculation unit 103 adds the stroke corresponding target wheel cylinder hydraulic pressure P1 * and the master cylinder hydraulic pressure compatible target wheel cylinder P2 * to calculate the final target wheel cylinder hydraulic pressure P *. When the target wheel cylinder hydraulic pressure P * is output to the motor control unit in the brake control unit BCU, the pump P is driven by the motor M. The motor control is not particularly limited as long as an existing motor control logic is appropriately used.

  Here, the operation obtained by the above configuration will be described. When the brake rigidity is low, the stroke amount STR increases, so the stroke-corresponding target wheel cylinder hydraulic pressure P1 * increases. At this time, since the master cylinder hydraulic pressure Pmc is difficult to increase, the master cylinder hydraulic pressure corresponding target wheel cylinder P2 * becomes small. As a result, when the stroke amount STR is excessive, the master cylinder M / C does not rise, so that excessive brake fluid is not pumped up, and an excessive stroke can be avoided. On the other hand, when the brake rigidity is high, the stroke amount STR is difficult to increase, and the stroke corresponding target wheel cylinder hydraulic pressure P1 * does not increase so much. At this time, since the master cylinder hydraulic pressure Pmc is likely to rise, the master cylinder hydraulic pressure corresponding target wheel cylinder P2 * becomes large. As a result, when the stroke amount STR is insufficient, the brake fluid is pumped up as the master cylinder hydraulic pressure increases, so that the plate stepping phenomenon can be avoided and an appropriate stroke amount STR can be secured. In this way, by overriding the excessive stroke and the stepping phenomenon that occur when control is performed using only the stroke amount using the master cylinder hydraulic pressure, the driver's braking intention is accurately reflected regardless of the brake rigidity. On the other hand, a brake control device with good pedal feeling can be provided.

  FIG. 3 is a control block diagram illustrating a control configuration of the brake assist control according to the first embodiment. The configuration shown in FIG. 3 takes the negative pressure of the brake booster BB into consideration when applying the concept shown in FIG. 2 to an actual brake control device. The stroke corresponding target wheel cylinder hydraulic pressure calculation unit 201 calculates a stroke corresponding target wheel cylinder hydraulic pressure P1 * corresponding to the stroke amount STR detected by the stroke sensor 17. The target master cylinder hydraulic pressure calculation unit 202 increases the target master cylinder hydraulic pressure Pmc * as the stroke amount STR detected by the stroke sensor 17 and the negative pressure of the brake booster BB detected by the negative pressure sensor 18 increase. Set. The deviation calculating unit 203 calculates a deviation ΔPmc between the target master cylinder hydraulic pressure Pmc * and the master cylinder hydraulic pressure Pmc detected by the master cylinder hydraulic pressure sensor 40. Master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure calculation unit 204 multiplies deviation ΔPmc by conversion coefficient K1 to calculate master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure P2 *. The target wheel cylinder hydraulic pressure calculation unit 205 calculates the final target wheel cylinder hydraulic pressure P * by adding the master cylinder hydraulic pressure compatible target wheel cylinder hydraulic pressure P2 * to the stroke corresponding target foil cylinder hydraulic pressure P1 *. .

  Here, the small master cylinder hydraulic pressure target foil cylinder hydraulic pressure P2 * means that the deviation ΔPmc between the target master cylinder hydraulic pressure Pmc * and the master cylinder hydraulic pressure Pmc becomes negative. That is, the master cylinder hydraulic pressure Pmc needs to be increased. In order to increase the master cylinder hydraulic pressure Pmc, it is necessary to weaken the action of pumping the brake fluid from the master cylinder M / C to the wheel cylinder W / C by the pump P (or stop the pump P). Therefore, the smaller the master cylinder hydraulic pressure target foil cylinder hydraulic pressure P2 * is, the larger the subtraction amount from the stroke corresponding target wheel cylinder hydraulic pressure P1 * is (the addition amount is negative). This is because the final target wheel cylinder hydraulic pressure P * is reduced, and the pressure increasing action by the pump P is weakened. Therefore, the phenomenon that the brake pedal BP is sucked in can be suppressed, and a good pedal feeling can be obtained.

  On the other hand, the master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure P2 * being large means that the deviation ΔPmc between the target master cylinder hydraulic pressure Pmc * and the master cylinder hydraulic pressure Pmc becomes positive. That is, there is no need to increase the master cylinder hydraulic pressure Pmc so much. In order to suppress the increase in the master cylinder hydraulic pressure Pmc, it is necessary to pump up brake fluid from the master cylinder M / C to the wheel cylinder W / C side by the pump P. Therefore, the larger the master cylinder hydraulic pressure target foil cylinder hydraulic pressure P2 *, the larger the amount added to the stroke corresponding target wheel cylinder hydraulic pressure P1 *. As a result, the final target wheel cylinder hydraulic pressure P * increases, and the pressure increasing action by the pump P is strengthened. Thereby, the brake assist control which ensured the pedal feeling according to negative pressure is realizable. Therefore, it is possible to suppress the pedaling phenomenon of the brake pedal BP and obtain a good pedal feeling.

As described above, the effects listed below are obtained in the first embodiment.
(1-1) Stroke sensor 17 (stroke calculation unit) that calculates the brake pedal operation stroke of the driver and master cylinder hydraulic pressure sensor 40 (master cylinder hydraulic pressure calculation) that calculates the hydraulic pressure Pmc of the master cylinder M / C ), Stroke corresponding target wheel cylinder hydraulic pressure P1 * set according to the calculated operation stroke, and master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure set according to the calculated master cylinder hydraulic pressure Pmc P2 * and a pump P that sucks in brake fluid from the master cylinder M / C and increases the wheel cylinder hydraulic pressure so that it becomes the target wheel cylinder hydraulic pressure, and the target wheel cylinder hydraulic pressure P * is stroke compatible A brake control device that calculates based on a target wheel cylinder hydraulic pressure P1 * and a master cylinder hydraulic pressure compatible target wheel cylinder hydraulic pressure P2 *.
Therefore, a good pedal feeling can be obtained.

(2-2) In the brake control device described in (1-1) above, the target wheel cylinder hydraulic pressure Pmc * is the stroke corresponding target wheel cylinder hydraulic pressure P1 * and master cylinder hydraulic pressure compatible target foil cylinder hydraulic pressure P2 *. A brake control device (see FIG. 2) that is calculated by addition.
Therefore, a good pedal feeling can be obtained.

(3-3) In the brake control device according to (1-1) above,
It has a brake booster BB (boost) that amplifies the driver's brake pedal operation force, and the target wheel cylinder hydraulic pressure P * is the negative pressure (amplification characteristic) of the brake booster BB and the calculated stroke amount STR (operation stroke) A brake control device calculated based on the calculated hydraulic pressure Pmc of the master cylinder (see FIG. 3).
By considering the negative pressure that is the amplification characteristic of the brake booster BB, a better pedal feeling can be obtained. The brake booster BB may be the negative pressure booster of the first embodiment or an electromagnetic booster that assists the operating force of the brake pedal BP by electrical control.

(4-4) In the brake control device according to (3-3), the brake booster BB is a negative pressure booster that amplifies the brake pedal operating force using negative pressure generated by the engine. Brake control device.
Therefore, the present invention can be applied to a vehicle equipped with a negative pressure booster that is often installed in existing vehicles. Moreover, even if the negative pressure is unstable, a good pedal feeling can be obtained.

(5-7) Pump P that draws in brake fluid from the master cylinder M / C and increases the wheel cylinder fluid pressure, and stroke sensor 17 that calculates the stroke amount STR (operation stroke) of the driver's brake pedal BP And the stroke-corresponding target wheel cylinder hydraulic pressure P1 * for assisting the increase of the wheel cylinder hydraulic pressure by the pump P so that the target wheel cylinder hydraulic pressure P * is set according to the calculated stroke amount STR. (Basic assist amount), target wheel cylinder hydraulic pressure calculation unit 103 (assist amount correction unit) that corrects the stroke-related target wheel cylinder hydraulic pressure P1 *, which is the basic assist amount, and the hydraulic pressure of the master cylinder M / C A master cylinder hydraulic pressure sensor 40 (master cylinder hydraulic pressure calculation unit), and the target wheel cylinder hydraulic pressure calculation unit 103 calculates the calculated stroke amount STR. Corrects the stroke corresponding target wheel cylinder pressure P1 * on the basis of the hydraulic pressure Pmc of static cylinder, brake control device being characterized in that the set of corrected target wheel cylinder pressure target wheel cylinder pressure P *.
Therefore, a good pedal feeling can be obtained when assisting the increase in the wheel cylinder hydraulic pressure.

(6-8) The brake control device described in (5-7) above includes a brake booster BB (booster) that amplifies the driver's brake pedal operation force, and the target wheel cylinder hydraulic pressure calculation unit 103 includes a brake booster. A brake control device that corrects a stroke-corresponding target wheel cylinder hydraulic pressure P1 * based on a negative pressure (amplification characteristic) of BB, a calculated stroke amount STR, and a calculated hydraulic pressure Pmc of a master cylinder.
By considering the negative pressure that is the amplification characteristic of the brake booster BB, a better pedal feeling can be obtained. The brake booster BB may be the negative pressure booster of the first embodiment or an electromagnetic booster that assists the operating force of the brake pedal BP by electrical control. In addition, when an electromagnetic booster is employ | adopted, a favorable pedal feeling can be obtained by correct | amending by an electromagnetic force instead of a negative pressure.

(7-9) In the brake control device described in (6-8) above, the brake booster BB is a negative pressure booster that amplifies the brake pedal operating force using the negative pressure generated by the engine. Brake control device.
Therefore, the present invention can be applied to a vehicle equipped with a negative pressure booster that is often installed in existing vehicles. Moreover, even if the negative pressure is unstable, a good pedal feeling can be obtained.

(8-10) In the brake control device described in (7-9) above, the target wheel cylinder hydraulic pressure calculation unit 205 (assist amount correction unit) calculates the target master cylinder hydraulic pressure Pmc * with respect to the calculated stroke amount STR. Calculate (target master cylinder hydraulic pressure calculation unit 202), and correct the target wheel cylinder hydraulic pressure based on the difference between the calculated target master cylinder hydraulic pressure Pmc * and the calculated master cylinder hydraulic pressure Pmc (target corresponding to master cylinder hydraulic pressure) A brake cylinder hydraulic pressure calculation unit 204).
Therefore, the target wheel cylinder hydraulic pressure can be achieved while securing an appropriate master cylinder hydraulic pressure, and a good pedal feeling can be obtained.

(9-13) The stroke amount STR (operation stroke) of the driver's brake pedal BP is calculated, and the target wheel cylinder hydraulic pressure P * set according to the calculated stroke amount STR and the master cylinder M / C Pump P that increases the brake cylinder fluid pressure so that the brake fluid is sucked and reaches the target wheel cylinder fluid pressure P *, and master cylinder fluid pressure sensor 40 that calculates the fluid pressure of the master cylinder M / C (master cylinder fluid pressure calculation) The target master cylinder hydraulic pressure Pmc * calculated based on the calculated stroke amount STR, and the target master cylinder hydraulic pressure Pmc * during the pressure increase by the pump P. A brake control device that reduces the master cylinder hydraulic pressure when the calculated master cylinder hydraulic pressure Pmc increases (hereinafter referred to as a master cylinder hydraulic pressure control unit).
Therefore, when the master cylinder hydraulic pressure Pmc is high, the master cylinder hydraulic pressure is reduced, so that a good pedal feeling can be obtained by avoiding the plate stepping phenomenon.

(10-14) In the brake control device according to (9-13) above, the master cylinder hydraulic pressure control unit calculates the calculated stroke amount STR and the calculated master cylinder pressure in the target wheel cylinder hydraulic pressure calculation unit 205. The target wheel cylinder hydraulic pressure P * is corrected based on the hydraulic pressure Pmc (target foil cylinder hydraulic pressure correction unit), the pump drive amount is determined so as to be the corrected target wheel cylinder hydraulic pressure P *, and the master cylinder is determined by the pump P. A brake control device that reduces the master cylinder hydraulic pressure Pmc by sucking out the brake fluid inside.
Therefore, by increasing the pressure increasing action by the pump P, the master cylinder hydraulic pressure Pmc can be reduced, and a good pedal feeling can be obtained by avoiding the plate stepping phenomenon.

(11-15) In the brake control device according to (9-14), the master cylinder hydraulic pressure control unit is configured to set a target wheel cylinder hydraulic pressure based on the calculated stroke amount STR and the calculated master cylinder hydraulic pressure Pmc. P * is corrected (equivalent to the target wheel cylinder hydraulic pressure calculation unit 205), and the corrected target wheel cylinder hydraulic pressure P * is set to the set target wheel cylinder hydraulic pressure, and the brake fluid in the master cylinder is sucked out by the pump P. A brake control device that reduces the hydraulic pressure Pmc.
Therefore, since the target wheel cylinder hydraulic pressure P * is corrected based on the master cylinder hydraulic pressure Pmc, it is possible to avoid the stepping phenomenon and obtain a good pedal feeling.

(Example 2)
Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. FIG. 4 is a configuration diagram of the brake control device according to the second embodiment. In the first embodiment, the pressure regulating reservoir 13 including the check valve 16 is provided. In contrast, the second embodiment includes reservoirs 130S and 130P (hereinafter collectively referred to as a reservoir 130) that do not include the check valve 16 instead of the pressure regulating reservoir 13, and includes a master cylinder M / C. The difference is that gate-in valves 50S and 50P (hereinafter collectively referred to as the gate-in valve 50) are provided on the pipeline 11 connecting the suction side of the pump P. The gate-in valve 50 is a normally closed type that closes when no power is supplied. In addition, a first check valve 30S that allows the flow of brake fluid from the reservoir 130 to the suction side of the pump P and prohibits the flow of brake fluid from the suction side of the pump P to the reservoir 130 side on the conduit 12 30P (hereinafter collectively referred to as the first check valve 30) and a second check valve arranged in series with the first check valve 30 between the first check valve 30 and the suction side of the pump P 31S, 31P (hereinafter collectively referred to as the second check valve 31). The pipeline 11 is connected between the first check valve 30 and the second check valve 31, and even if the gate-in valve 50 is opened, the brake fluid does not flow into the reservoir 130 from the master cylinder M / C side. It is configured.

  At the time of brake assist control, the gate-in valve 50 is opened, and the driving state of the pump P is controlled based on the target wheel cylinder hydraulic pressure P * and the target master cylinder hydraulic pressure Pmc * as in the first embodiment. Supply brake fluid from the / C side to the wheel cylinder W / C side. Here, in the second embodiment, when the actual master cylinder hydraulic pressure Pmc exceeds the master cylinder hydraulic pressure Pmc * by a predetermined value or more, the solenoid-out valve 15 is opened and the wheel cylinder W / C is supplied to the reservoir 130. Allow the brake fluid to drain. As a result, the brake fluid pumped from the master cylinder M / C by the pump P is increased, and the master cylinder hydraulic pressure Pmc is decreased to achieve the target master cylinder hydraulic pressure Pmc *. Thereby, in Example 2, in addition to the effect similar to Example 1, the following effect is obtained.

(12-16) In the brake control device described in (9-113) above, a conduit 14 (reduced pressure oil passage) connecting the wheel cylinder W / C and the reservoir 130, and a solenoid-out valve provided in the conduit 14 15 (pressure reducing valve), the master cylinder hydraulic pressure controller opens the solenoid out valve 15 to reduce the wheel cylinder hydraulic pressure, and brake fluid to the wheel cylinder W / C reduced from the master cylinder M / C. And a master cylinder hydraulic pressure Pmc is reduced.
In other words, by operating the solenoid out valve 15, it is possible to avoid the stepping phenomenon and obtain a good pedal feeling.

(Example 3)
Next, Example 3 will be described. Since the basic configuration is the same as that of the second embodiment, different points will be described. FIG. 5 is a configuration diagram of the brake control device according to the third embodiment. In the second embodiment, the first check valve 30 is provided so that the brake fluid of the master cylinder M / C does not flow into the reservoir 130. In contrast, the third embodiment is different in that the first check valve 30 is eliminated. The pipeline 11 is connected to the pipeline 12 on the reservoir 130 side with respect to the second check valve 31. The pipes on the pump P side from this connection point are the intake oil passages 12S1, 12P1, and the pipes on the reservoir 130 side from the connection point are the decompression oil passages 12S2, 12P2.

  In the third embodiment, the brake fluid can be directly supplied from the master cylinder M / C to the reservoir 130. Therefore, it is not necessary to open the solenoid-out valve 15 as in the second embodiment. When the drive amount of the pump P is less than the drive amount according to the driver's brake pedal operation and the master cylinder hydraulic pressure Pmc increases, the hydraulic pressures in the suction oil passage portions 12S1, 12P1 increase. Then, the brake fluid automatically flows into the reservoir 130 through the decompression oil passage portions 12S2 and 12P2, and a pedal stroke can be secured. Therefore, the board step phenomenon can be suppressed.

(13-17) In the brake control device according to (9-13) above, the pipeline 1 (first oil passage) connecting the master cylinder M / C and the wheel cylinder W / C, and the pipeline 1 branch off. The pipe 11 (second oil path), the pipe 11 includes suction oil passages 12S1 and 12P1 connected to the pump P, and decompression oil passages 12S2 and 12P2 connected to the reservoir 130, and is provided in the master cylinder M / C. Brake control device characterized in that the brake fluid is supplied to the pump P and the reservoir 130 by a pipe 11.
When the master cylinder fluid pressure Pmc rises, the brake fluid in the master cylinder M / C automatically flows into the reservoir 130, so that the plate stepping phenomenon can be prevented.

Example 4
Next, Example 4 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. FIG. 6 is a control block diagram illustrating a control configuration of brake assist control according to the fourth embodiment. The brake assist control configuration of the fourth embodiment includes a storage device 301 including a nonvolatile memory that can hold information even when the power is turned off. The storage device 301 stores a signal from the ignition switch IGN, a stroke amount STR output from the stroke sensor 17, and a target wheel cylinder hydraulic pressure P * with respect to the stroke amount STR. In other words, the stroke-corresponding target wheel cylinder hydraulic pressure P1 * is corrected according to the negative pressure of the brake booster BB and the master cylinder hydraulic pressure Pmc, and the corrected final target wheel cylinder hydraulic pressure P * is the stroke amount STR. And store it in correspondence.

  Normally, when the ignition switch IGN is turned OFF, the values in each control configuration are initialized. Therefore, when the ignition switch IGN is turned on next time, it is necessary to read the negative pressure and the master cylinder pressure Pmc again and calculate the final target wheel cylinder hydraulic pressure P * corrected thereafter. For this reason, there is a possibility that a delay may occur before the appropriate target wheel cylinder hydraulic pressure P * is output. Therefore, the storage device 301 stores a correspondence relationship between the stroke amount STR stored in the previous control and the target wheel cylinder hydraulic pressure P *. When the ignition switch IGN is switched from OFF to ON, the stored target wheel cylinder hydraulic pressure P * corresponding to the stroke amount STR output from the stroke sensor 17 is output as an initial value. Thereby, appropriate control can be performed immediately after the ignition switch IGN is turned ON. After a predetermined period has elapsed since the ignition switch IGN was turned ON, the control is switched to normal control processing.

As described above, the following operational effects are obtained in the fourth embodiment.
(14-5) In the brake control device according to (1-1), the brake control device includes a storage device 301 (target wheel cylinder hydraulic pressure storage unit) that stores the calculated target wheel cylinder hydraulic pressure P *, and the pump P A brake control device, wherein the wheel cylinder hydraulic pressure is increased to a stored target wheel cylinder hydraulic pressure.
Therefore, by using the stored target wheel cylinder hydraulic pressure, control can be executed without waiting for the calculation process, and a decrease in control responsiveness can be suppressed. In the fourth embodiment, the stored value is used only when the ignition switch IGN is changed from OFF to ON. However, after the correction control is performed once, a predetermined change that does not cause a large change such as secular change occurs. You may control using the value of the memory | storage device 301 continuously for a period (between a predetermined number of days and predetermined distance).
(15-6) The brake control device according to (14-5), wherein the storage device 301 is a nonvolatile memory.
Therefore, the brake assist control can be started without waiting for the calculation process based on the master cylinder pressure when the ignition switch IGN is turned from OFF to ON next time.

(16-11) The brake control device according to (5-7) above, further comprising a storage device 301 (target wheel cylinder hydraulic pressure storage unit) for storing the calculated target wheel cylinder hydraulic pressure P *, and the target wheel cylinder The hydraulic pressure calculation unit 103 (assist amount correction unit) determines the driving amount of the pump P so that the target wheel cylinder hydraulic pressure stored after correction is obtained.
Therefore, by using the stored target wheel cylinder hydraulic pressure, control can be executed without waiting for the correction process, and a decrease in control responsiveness can be suppressed.
(17-12) The brake control device according to (16-11), wherein the storage device 301 is a nonvolatile memory.
Therefore, the next time the ignition switch IGN is turned from OFF to ON, the brake assist control can be started without waiting for correction based on the master cylinder pressure.

1 pipeline
3 Gate-out valve
5 Check valve
6 Solenoid in valve
11 pipeline
12 pipelines
12S1, 12P1 Suction oil passage
12S2, 12P2 Depressurized oil passage
13 Pressure regulating reservoir
14 pipelines
15 Solenoid out valve
16 Check valve
17 Stroke sensor
18 Negative pressure sensor
20 Motor drive
30 First check valve
31 Second check valve
40 Master cylinder fluid pressure sensor
50 Gate-in valve
101 Stroke target wheel cylinder hydraulic pressure calculator
102 Master cylinder hydraulic pressure target wheel cylinder hydraulic pressure calculator
103 Target wheel cylinder hydraulic pressure calculator
130 Reservoir
201 Stroke target wheel cylinder hydraulic pressure calculator
202 Target master cylinder hydraulic pressure calculator
203 Deviation calculator
204 Master cylinder hydraulic pressure target wheel cylinder hydraulic pressure calculator
205 Target wheel cylinder hydraulic pressure calculator
301 storage device
BB brake booster
BCU Brake control unit
BP brake pedal
HU hydraulic control unit
IGN ignition switch
M motor
M / C master cylinder
P pump
W / C wheel cylinder
RSV reservoir tank

Claims (15)

A stroke calculation unit that calculates an operation stroke of the brake pedal of the driver;
A master cylinder hydraulic pressure calculator for calculating the hydraulic pressure of the master cylinder;
Stroke corresponding target wheel cylinder hydraulic pressure set according to the calculated operation stroke;
Master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure set according to the calculated master cylinder hydraulic pressure,
A pump that draws in brake fluid from the master cylinder and increases the wheel cylinder hydraulic pressure so as to reach the target wheel cylinder hydraulic pressure;
The target wheel cylinder hydraulic pressure is calculated based on the stroke corresponding target wheel cylinder hydraulic pressure and the master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure. The brake control device according to claim 1, wherein
The target wheel cylinder hydraulic pressure is calculated by adding the stroke corresponding target wheel cylinder hydraulic pressure and the master cylinder hydraulic pressure corresponding target wheel cylinder hydraulic pressure. The brake control device according to claim 1, wherein
A booster for amplifying the driver's brake pedal operating force;
The target wheel cylinder hydraulic pressure is calculated based on an amplification characteristic of the booster, the calculated operation stroke, and the calculated master cylinder hydraulic pressure. The brake control device according to claim 3,
The brake control device according to claim 1, wherein the booster is a negative pressure booster that amplifies the brake pedal operation force using a negative pressure generated by an engine. The brake control device according to claim 1, wherein
A target foil cylinder hydraulic pressure storage unit for storing the calculated target foil cylinder hydraulic pressure;
The brake control device according to claim 1, wherein the pump increases the wheel cylinder hydraulic pressure so as to be the stored target wheel cylinder hydraulic pressure. The brake control device according to claim 5,
The target wheel cylinder hydraulic pressure storage unit is a non-volatile memory. A pump that draws in brake fluid from the master cylinder and increases the hydraulic pressure in the wheel cylinder;
A stroke calculation unit that calculates an operation stroke of the brake pedal of the driver;
A basic assist amount for assisting the pump to increase the wheel cylinder hydraulic pressure so as to achieve a target wheel cylinder hydraulic pressure set according to the calculated operation stroke;
An assist amount correction unit for correcting the basic assist amount;
A master cylinder hydraulic pressure calculating section for calculating the hydraulic pressure of the master cylinder;
The assist amount correcting unit corrects the target wheel cylinder hydraulic pressure based on the calculated operation stroke and the calculated hydraulic pressure of the master cylinder, and sets the corrected target wheel cylinder hydraulic pressure to the set target wheel cylinder. Brake control device characterized by hydraulic pressure. The brake control device according to claim 7,
A booster for amplifying the driver's brake pedal operating force;
The assist control unit corrects the target wheel cylinder hydraulic pressure based on the amplification characteristic of the booster, the calculated operation stroke, and the calculated hydraulic pressure of the master cylinder. The brake control device according to claim 8,
The brake control device according to claim 1, wherein the booster is a negative pressure booster that amplifies the brake pedal operation force using a negative pressure generated by an engine. The brake control device according to claim 7,
The assist amount correction unit calculates a target master cylinder hydraulic pressure for the calculated operation stroke, and calculates a target wheel cylinder hydraulic pressure based on a difference between the calculated target master cylinder hydraulic pressure and the calculated master cylinder hydraulic pressure. Brake control device characterized by correcting. The brake control device according to claim 7,
A target foil cylinder hydraulic pressure storage unit for storing the corrected target foil cylinder hydraulic pressure;
The brake drive device according to claim 1, wherein the pump drive amount setting unit determines the pump drive amount so as to be the stored target wheel cylinder hydraulic pressure after correction. The brake control device according to claim 11,
The target wheel cylinder hydraulic pressure storage unit is a non-volatile memory. The driver's brake pedal operation stroke is calculated, and the target wheel cylinder hydraulic pressure is set according to the calculated operation stroke;
A pump that draws in brake fluid from the master cylinder and increases the wheel cylinder hydraulic pressure so as to be the target wheel cylinder hydraulic pressure;
A master cylinder hydraulic pressure calculating section for calculating the hydraulic pressure of the master cylinder;
A target master cylinder hydraulic pressure calculation unit for calculating a target master cylinder hydraulic pressure calculated based on the calculated operation stroke;
A master cylinder hydraulic pressure control unit that reduces the master cylinder hydraulic pressure when the calculated master cylinder hydraulic pressure becomes higher than the target master cylinder hydraulic pressure during pressure increase by the pump;
A brake control device comprising: The brake control device according to claim 13,
The master cylinder hydraulic pressure control unit includes a target wheel cylinder hydraulic pressure correction unit that corrects the target wheel cylinder hydraulic pressure based on the calculated operation stroke and the calculated hydraulic pressure of the master cylinder,
A brake control device that determines the pump drive amount so as to be the corrected target wheel cylinder hydraulic pressure, and reduces the master cylinder hydraulic pressure by sucking out brake fluid in the master cylinder by the pump. . The brake control device according to claim 13,
The master cylinder hydraulic pressure control unit corrects the target wheel cylinder hydraulic pressure based on the calculated operation stroke and the calculated hydraulic pressure of the master cylinder, and sets the corrected target wheel cylinder hydraulic pressure to the set target target. A brake control device characterized by reducing the master cylinder hydraulic pressure by sucking brake fluid in the master cylinder by the pump as wheel cylinder hydraulic pressure.

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