JP6582617B2 - Brake device for vehicle - Google Patents

Description

  The present invention relates to a brake device for a vehicle.

  When braking force is applied to a running vehicle and the vehicle is decelerating, the ground load on the front wheels tends to increase due to the moment generated by the inertial force, while the ground load on the rear wheels tends to decrease It becomes like this. If the deceleration of the vehicle immediately before the vehicle stops is large, the vehicle stops in a forward leaning posture due to the above moment, and a swing occurs. As a result, vehicle pitching is likely to occur. That is, if the deceleration of the vehicle immediately before the vehicle stops is large, it can be said that the vehicle is likely to pitch.

  Patent Document 1 describes an example of a vehicle brake device that can suppress the occurrence of pitching of the vehicle when the vehicle is stopped. In this brake device, the braking force applied to the vehicle when the vehicle is decelerated from the decelerating state in a situation where the vehicle is decelerating due to the braking force being applied to the vehicle. Pitching suppression control is performed to reduce the. By performing such control, the deceleration of the vehicle immediately before the vehicle stops is reduced, so that the vehicle is unlikely to lean forward, and as a result, the pitching of the vehicle when the vehicle is stopped can be suppressed. That is, by reducing the deceleration of the vehicle just before the vehicle stops, it becomes possible to suppress the pitching of the vehicle.

JP-A-5-270376

  By the way, while the braking force to be applied to the vehicle is being reduced by performing the above-described pitching suppression control, it may be necessary to perform so-called sudden braking in which the braking force to be applied to the vehicle is suddenly increased. When sudden braking is necessary, for example, an obstacle such as a person suddenly appears in front of the vehicle, a preceding vehicle traveling in front of the own vehicle performs sudden braking, and the preceding vehicle It can be mentioned that the distance up to is abruptly shortened.

  The object of the present invention is to reduce the braking force applied to the vehicle when sudden braking is required even when the braking force applied to the vehicle is reduced in order to suppress pitching when the vehicle is stopped. An object of the present invention is to provide a vehicle brake device capable of assisting rapid increase.

  A vehicle brake device for solving the above-described problem is a vehicle in which a braking force applied to a vehicle is increased when a brake operation amount, which is an operation amount of a brake operation member, is increased, and a vehicle is operated when the brake operation amount is decreased. Is a device that reduces the braking force applied to the. The vehicle brake device includes a reaction force generation device that adjusts a reaction force applied to a brake operation member, and a state in which the vehicle decelerates to a state in which the vehicle stops under a situation in which a brake force is applied to the vehicle. And a control device that performs pitching suppression auxiliary control that increases the reaction force applied from the reaction force generator to the brake operation member in the transition period. The control device ends the execution of the pitching suppression assist control when the sudden braking execution condition is satisfied during the execution of the pitching suppression assist control.

  When the reaction force applied to the brake operation member from the reaction force generator is increased under the situation where the brake operation member is operated by the driver, the amount of brake operation is likely to decrease. On the other hand, if the reaction force is reduced under a situation where the driver is operating the brake operation member, the amount of brake operation is likely to increase.

  According to the above configuration, when the pitching suppression assist control is performed in a situation where the driver is operating the brake operation member, the reaction force applied from the reaction force generator to the brake operation member is increased. When the amount of brake operation is reduced due to such an increase in reaction force, the braking force applied to the vehicle is reduced. As a result, the deceleration of the vehicle immediately before the vehicle stops is reduced, and the pitching of the vehicle when the vehicle is stopped can be suppressed.

  However, when the sudden braking execution condition is satisfied during the execution of the pitching suppression assist control, the pitching suppression assist control is terminated, and the reaction force applied from the reaction force generator to the brake operation member is not increased. For this reason, even when sudden braking is required, the amount of brake operation is easily increased as compared with the case where the increase in reaction force is continued. That is, by not increasing the reaction force, it is possible to favorably assist the increase in the brake operation amount. Then, the brake operation amount is increased early by such assist, so that the braking force applied to the vehicle is increased early. Therefore, even when the braking force applied to the vehicle is reduced to suppress pitching when the vehicle is stopped, the brake force applied to the vehicle is quickly increased when sudden braking is required. You will be able to assist.

  Note that as the reaction force applied from the reaction force generator to the brake operation member is smaller, the increase speed of the brake operation amount is likely to increase. Therefore, in the above-described vehicle brake device, the control device terminates the execution of the pitching suppression assist control when the sudden braking execution condition is satisfied while the pitching suppression assist control is being performed, and the reaction force generation device starts the brake operation member. It is preferable to implement sudden brake assist control that reduces the reaction force applied to the vehicle. According to this configuration, by reducing the reaction force applied to the brake operation member from the reaction force generator by performing the sudden brake assist control, it is possible to further enhance the assist effect of the early increase in the brake operation amount. Therefore, when sudden braking becomes necessary, it is possible to assist more effectively in the early increase of the braking force applied to the vehicle.

  Here, during the execution of the pitching suppression assist control, the reaction force applied from the reaction force generator to the brake operation member may be increased stepwise. In this case, the brake operation member is operated. The feeling felt by the driver is changed in stages, and the driver is likely to feel uncomfortable. Therefore, it is preferable that the control device gradually increases the reaction force applied from the reaction force generator to the brake operation member in the pitching suppression assist control. According to this configuration, since the reaction force gradually increases, the feeling felt by the driver who operates the brake operation member gradually changes. For this reason, it is possible to suppress the deterioration of the feeling given to the driver who operates the brake operation member.

The block diagram which shows the outline of a vehicle provided with the brake device of the vehicle of one Embodiment. The flowchart explaining the process routine performed in order to control the brake force given to a vehicle, which is a process routine performed by the control apparatus with which the brake device of the vehicle is provided. The flowchart explaining the process routine performed in order to adjust the reaction force given to a brake pedal from the reaction force generator, which is a process routine performed by the control device. FIG. 6 is a timing chart when the vehicle stops due to a brake operation by a driver, where (a) shows a change in the vehicle body speed of the vehicle, (b) shows a change in the brake operation amount, and (c) shows a reaction force generation. The transition of the reaction force applied to the brake pedal from the device is shown, and (d) shows the transition of the braking force applied to the vehicle. The timing chart for demonstrating an example of the method of determining whether the execution conditions of sudden braking were satisfied based on the change of the amount of brake operation.

Hereinafter, an embodiment of a vehicle brake device will be described with reference to FIGS.
FIG. 1 illustrates an example of a vehicle including the vehicle brake device 11 of the present embodiment. As shown in FIG. 1, the vehicle is provided with a brake mechanism 100 for a plurality of wheels FL, FR, RL, and RR. The brake mechanism 100 includes a wheel cylinder 101, and applies a larger braking force to the wheels FL, FR, RL, and RR as the WC pressure, which is the hydraulic pressure in the wheel cylinder 101, increases.

  The vehicle brake device 11 includes a stroke simulator 21 that operates in response to an operation of a brake pedal 12 that is an example of a brake operation member. A brake pedal 12 is drivingly connected to the stroke simulator 21, and a piston 22 that moves forward and backward in the horizontal direction in the figure and a reaction force spring 23 that applies a biasing force in the right direction in the figure to the piston 22. Is provided. In addition, brake fluid is stored in the stroke simulator 21, and the brake operation amount, which is the operation amount of the brake pedal 12 by the driver, increases, and the stroke simulator 21 moves as the piston 22 moves to the left in the figure. The hydraulic pressure inside is increased. Therefore, when the brake pedal 12 is operated by the driver, a reaction force corresponding to the sum of the urging force from the reaction force spring 23 and the hydraulic pressure in the stroke simulator 21 is applied to the brake pedal 12.

  The brake device 11 of the vehicle according to the present embodiment includes a reservoir tank 13 in which brake fluid is stored, a supply pump 24 that supplies the brake fluid in the reservoir tank 13 into the stroke simulator 21, and an interior of the stroke simulator 21. And a discharge valve 25 that operates when the brake fluid is discharged into the reservoir tank 13. That is, as the amount of brake fluid supplied into the stroke simulator 21 by the operation of the supply pump 24 increases, the hydraulic pressure in the stroke simulator 21 increases, and as a result, the reaction force applied to the brake pedal 12 increases.

  On the other hand, when the discharge valve 25 is operated, the brake fluid is discharged from the stroke simulator 21 into the reservoir tank 13. As the amount of brake fluid discharged from the stroke simulator 21 increases, the hydraulic pressure in the stroke simulator 21 decreases, and as a result, the reaction force applied to the brake pedal 12 decreases. That is, by controlling the supply pump 24 and the discharge valve 25, the reaction force applied to the brake pedal 12 is adjusted. Therefore, in the vehicle brake device 11 of the present embodiment, the “reaction force generator 20” includes the stroke simulator 21, the supply pump 24, and the discharge valve 25.

  Further, the brake device 11 of the vehicle is provided with a hydraulic pressure generating device 30 whose operation is controlled by the control device 50 and a brake actuator 40. The hydraulic pressure generator 30 includes a motor 31 that can rotate the output shaft 311 in both forward and reverse directions, a conversion mechanism 32 that converts the rotational motion of the motor 31 into linear motion, and power from the motor 31 through the conversion mechanism 32. Is input to the slave cylinder 33. The slave pressure, which is the hydraulic pressure generated in the hydraulic chamber 331 in the slave cylinder 33, can be adjusted by the rotation of the motor 31. That is, the slave pressure is high when the output shaft 311 of the motor 31 is rotating in the forward direction, and is low when the output shaft 311 is rotating in the reverse direction, which is the opposite direction of the forward direction.

  A brake actuator 40 is connected to the slave cylinder 33 through the connection flow path 14. From the slave cylinder 33, an amount of brake fluid corresponding to the slave pressure is supplied to the brake actuator 40 through the connection flow path 14.

  Each wheel cylinder 101 is connected to the brake actuator 40. When the brake actuator 40 is not operated, an amount of brake fluid corresponding to the amount of brake fluid supplied from the slave cylinder 33 is supplied into the wheel cylinder 101. In this case, the WC pressure in the wheel cylinder 101 is substantially equal to the slave pressure in the slave cylinder 33. That is, as the output shaft 311 of the motor 31 rotates in the positive direction and the slave pressure increases, the WC pressure increases and the brake force BP applied to the vehicle increases. On the other hand, as the output shaft 311 of the motor 31 rotates in the reverse direction and the slave pressure decreases, the WC pressure decreases and the braking force BP applied to the vehicle decreases.

  The brake actuator 40 is provided with various valves. By controlling the driving of these valves, the WC pressure in the wheel cylinder 101 is adjusted individually.

Next, the control device 50 that controls the vehicle brake device 11 will be described.
As shown in FIG. 1, a wheel speed sensor 501, a stroke sensor 502, and a brake switch 503 are electrically connected to the control device 50. The wheel speed sensor 501 is provided for each of the wheels FL, FR, RL, and RR, and detects the wheel speed VW of the corresponding wheel. The stroke sensor 502 detects a brake operation amount BIN that is an operation amount of the brake pedal 12. The brake switch 503 detects whether or not the brake pedal 12 is operated.

  Further, the reaction device 20, the fluid pressure generator 30, and the brake actuator 40 are electrically connected to the control device 50. And the control apparatus 50 controls the reaction force generator 20, the hydraulic pressure generator 30, and the brake actuator 40 based on the information detected by various detection systems, such as a sensor.

  Next, a processing routine executed when controlling the hydraulic pressure generating device 30 according to the driver's brake operation will be described with reference to the flowchart shown in FIG. This processing routine is a processing routine that is executed for each preset control cycle.

  As shown in FIG. 2, the control device 50 determines whether or not the brake is being operated (step 11). For example, the control device 50 can determine whether or not the brake is being operated based on a signal input from the brake switch 503. Further, the control device 50 may determine that the brake is being operated when the brake operation amount BIN detected by the stroke sensor 502 is equal to or greater than a predetermined determination value.

  If the brake is not being operated (step 11: NO), the control device 50 ends the present processing routine once without driving the motor 31. On the other hand, when the brake is being operated (step 11: YES), the control device 50 calculates the required brake force BPR based on the brake operation amount BIN detected by the stroke sensor 502 (step 12). At this time, the required brake force BPR is set to a larger value as the brake operation amount BIN is larger. And the control apparatus 50 controls the motor 31 according to the calculated request | requirement brake force BPR (step 13). Specifically, the control device 50 controls the motor 31 so that the output shaft 311 rotates in the positive direction when the required brake force BPR is increasing, and the output shaft 311 when the required brake force BPR is decreasing. Controls the motor 31 to rotate in the opposite direction. That is, the brake force BP applied to the vehicle is increased when the brake operation amount BIN is increased, and the brake force BP applied to the vehicle is decreased when the brake operation amount BIN is decreased. Thereafter, the control device 50 once ends this processing routine.

  By the way, in the vehicle brake device 11 of the present embodiment, the pitching suppression assisting control for assisting the suppression of the pitching of the vehicle when the vehicle is stopped is performed. In this pitching suppression auxiliary control, the reaction force applied to the brake pedal 12 operated by the driver is increased to prompt the driver to reduce the brake operation amount BIN. When the brake operation amount BIN is decreased, the WC pressure in the wheel cylinder 101 is decreased in accordance with the decrease in the brake operation amount BIN.

However, sudden braking may be required while the WC pressure is being reduced due to the execution of the pitching suppression auxiliary control. As a case where sudden braking is required, for example, the following cases can be cited.
-When the preceding vehicle, which is a vehicle traveling ahead of the host vehicle, suddenly brakes, the distance from the host vehicle to the preceding vehicle suddenly decreases.
・ When an obstacle such as a person or vehicle suddenly appears in front of the vehicle.

  And when sudden braking becomes necessary for the reasons as described above, the vehicle brake device 11 of the present embodiment finishes the pitching suppression assist control, and then performs the sudden brake assist control. I have to. In this sudden brake assist control, the reaction force applied to the brake pedal 12 operated by the driver is reduced to assist early increase of the brake operation amount BIN. When the brake operation amount BIN is increased, the WC pressure in the wheel cylinder 101 is increased in accordance with the increase in the brake operation amount BIN.

  Next, a processing routine executed by the control device 50 to adjust the reaction force X applied from the reaction force generator 20 to the brake pedal 12 will be described with reference to the flowchart shown in FIG. This processing routine is a processing routine executed when the brake pedal 12 is operated.

  As shown in FIG. 3, the control device 50 determines whether or not it is a transition period from a deceleration state in which the vehicle decelerates to a stop state in which the vehicle stops (step S21). For example, the control device 50 can determine that the vehicle body speed VS is higher than the transition determination speed VSTH1, and is not yet in the transition period, and when the vehicle body speed VS is equal to or lower than the transition determination speed VSTH1, it is in the transition period. Judgment can be made. Also, it can be determined that it is not a transition period when the vehicle has already stopped. The vehicle body speed VS is a value calculated based on at least one of the wheel speeds VW of the wheels FL, FR, RL, RR.

  And when it is not a transition period (step S21: NO), the control apparatus 50 once complete | finishes this process routine. On the other hand, when it is a transition period (step S21: YES), the control apparatus 50 performs pitching suppression auxiliary control (step S22). That is, the control device 50 operates the supply pump 24 of the reaction force generator 20 to increase the hydraulic pressure in the stroke simulator 21. At this time, the increasing speed of the hydraulic pressure in the stroke simulator 21 is relatively increased so that the driver can recognize the increase in the reaction force X applied from the reaction force generator 20 to the brake pedal 12. Subsequently, the control device 50 determines whether or not a sudden braking execution condition is satisfied (step S23). For example, the control device 50 can determine that the sudden braking execution condition is satisfied when the brake operation amount BIN by the driver is suddenly increased.

  Here, with reference to FIG. 5, an example of a method for determining whether or not the sudden braking execution condition is satisfied based on the change in the brake operation amount BIN will be described. That is, as shown in FIG. 5, the pitching suppression assist control is started at the first timing t21 while the vehicle is decelerating by the brake operation by the driver. As a result, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 increases. If the operation force of the brake pedal 12 by the driver does not change even when such auxiliary control is performed, the brake operation amount BIN is decreased as the reaction force X increases.

  Further, at the first timing t21 when the pitching suppression assist control is started, the sudden brake determination operation amount BINTH is set. For example, the sudden brake determination operation amount BINTH can be set to a value equal to the difference obtained by subtracting the predetermined offset value α from the brake operation amount BIN at the start of the pitching suppression assist control.

  In the example shown in FIG. 5, the brake operation amount BIN is smaller than the sudden brake determination operation amount BINTH at the second timing t22 when the predetermined time TTH has elapsed from the first timing t21. However, from the third timing t23 thereafter, the brake operation amount BIN starts to increase despite the reaction force X being increased by the execution of the pitching suppression assist control. Since the brake operation amount BIN reaches the sudden brake determination operation amount BINTH at the fourth timing t24, it can be determined that the driver is requesting sudden braking.

  That is, when the brake operation amount BIN becomes equal to or greater than the sudden brake determination operation amount BINTH after the predetermined time TTH has elapsed since the start of the pitching suppression assist control, the operating force of the brake pedal 12 by the driver is increased. Can be considered. Therefore, at such a time, it can be determined that the sudden braking execution condition is satisfied.

  Returning to FIG. 3, when the sudden braking execution condition is satisfied (step S <b> 23: YES), the control device 50 ends the pitching suppression auxiliary control and stops the operation of the supply pump 24 of the reaction force generator 20. (Step S24). Then, the control device 50 performs a sudden brake assist process (step S25). That is, the control device 50 opens the discharge valve 25 of the reaction force generating device 20 and discharges the brake fluid from the stroke simulator 21 into the reservoir tank 13, thereby reducing the hydraulic pressure in the stroke simulator 21.

  Subsequently, the control device 50 determines whether or not the vehicle is stopped (step S26). For example, the control device 50 can determine that the vehicle has stopped when the duration of the state where the vehicle body speed VS of the vehicle is equal to or lower than the stop determination speed VSTH2 is equal to or longer than a specified time. And when the vehicle has not stopped (step S26: NO), the control apparatus 50 transfers the process to step S25 mentioned above, and continues implementation of the sudden brake assistance process. On the other hand, when the vehicle is stopped (step S26: YES), the control device 50 ends the execution of the sudden brake assist processing, closes the discharge valve 25 of the reaction force generation device 20, and then performs this processing routine. Is temporarily terminated.

  On the other hand, in step S23, when the conditions for sudden braking are not satisfied (NO), the control device 50 determines whether or not the vehicle is just before stopping (step S27). For example, the control device 50 can determine that the vehicle is about to stop when the vehicle body speed VS is equal to or less than the determination speed VSTH3 immediately before stop. The determination speed VSTH3 immediately before stop is set to a value that is smaller than the transition determination speed VSTH1 and is equal to or higher than the stop determination speed VSTH2.

  When the vehicle is not yet immediately before stopping (step S27: NO), the control device 50 shifts the process to step S22 described above, and continues the pitching suppression assist control. On the other hand, when the vehicle is just before stopping (step S27: YES), the control device 50 ends the pitching suppression auxiliary control and stops the operation of the supply pump 24 of the reaction force generating device 20 (step S28). Subsequently, the control device 50 carries out vehicle stop control (step S29). That is, the control device 50 opens the discharge valve 25 of the reaction force generating device 20 and discharges the brake fluid from the stroke simulator 21 into the reservoir tank 13, thereby reducing the hydraulic pressure in the stroke simulator 21. In this case, the control device 50 controls the discharge valve 25 so that the decreasing speed of the hydraulic pressure in the stroke simulator 21 is smaller than the decreasing speed of the hydraulic pressure when the sudden brake assist process is performed.

  And the control apparatus 50 determines whether the vehicle has stopped (step S30). When the vehicle is not stopped (step S30: NO), the control device 50 shifts the process to the above-described step S29, and continues the execution of the vehicle stop process. On the other hand, when the vehicle is stopped (step S30: YES), the control device 50 ends the execution of the vehicle stop processing, closes the discharge valve 25 of the reaction force generation device 20, and then performs this processing routine. Is temporarily terminated.

Next, with reference to the timing chart shown in FIG. 4, the operation and effect of the vehicle brake device 11 of this embodiment will be described.
(1) As shown in FIGS. 4A, 4B, 4C, and 4D, when the driver operates the brake pedal 12 while the vehicle is running, a braking force BP is applied to the vehicle and the vehicle is Slow down. The vehicle deceleration at this time is a deceleration according to the brake operation amount BIN. During vehicle deceleration, the ground load on the front wheels FL and FR increases while the ground load on the rear wheels RL and RR decreases.

  Then, at the first timing t11 during such vehicle deceleration, the vehicle body speed VS of the vehicle becomes equal to the transition determination speed VSTH1. Then, since it can be determined that the transition period from the state where the vehicle decelerates to the state where the vehicle stops is reached (step S21: YES), the pitching suppression auxiliary control is started (step S22). When the pitching suppression assist control is thus started, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 gradually increases.

  At this time, when the operating force of the brake pedal 12 by the driver does not change, the brake operation amount BIN decreases as the reaction force X increases. That is, increasing the reaction force X applied to the brake pedal 12 from the reaction force generator 20 assists the reduction of the brake operation amount BIN. When the brake operation amount BIN is thus reduced, the required brake force BPR is also reduced (step S12). As a result, the WC pressure in the wheel cylinder 101 is reduced (step S13), and the braking force BP applied to the vehicle is reduced. Thereby, the deceleration of the vehicle is also reduced.

  When the reaction force X applied from the reaction force generator 20 to the brake pedal 12 changes, the feeling of the driver who operates the brake pedal 12 changes. Therefore, when the reaction force X is increased stepwise during the execution of the pitching suppression assist control, the operation feeling of the brake pedal 12 changes stepwise, and the driver may feel uncomfortable. In this respect, since the reaction force X is gradually increased in the vehicle brake device 11 of the present embodiment, the operation feeling of the brake pedal 12 changes little by little, and the driver is less likely to feel uncomfortable.

  (2) Incidentally, if the brake operation amount BIN does not change even when the reaction force X applied from the reaction force generator 20 to the brake pedal 12 is increased by performing the pitching suppression assist control, the brake applied to the vehicle The force BP does not change. That is, priority can be given to the driver's will to operate the brake pedal 12 even during the execution of the pitching suppression assist control.

  (3) At the second timing t12 during the execution of such pitching suppression assist control, when the sudden braking execution condition is satisfied (step S23: YES), the pitching suppression assist control is terminated (step S24). . That is, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 is not increased after the second timing t12. Therefore, the brake operation amount BIN is likely to be larger than before the second timing t12. That is, by preventing the reaction force X from increasing, an increase in the brake operation amount BIN is assisted.

  Then, as the brake operation amount BIN increases, the required brake force BPR is increased (step S12), and the WC pressure in the wheel cylinder 101 is increased (step S13). Then, the braking force BP applied to the vehicle is increased, and the deceleration of the vehicle is increased. Therefore, even when the braking force BP to be applied to the vehicle is reduced in order to suppress the pitching when the vehicle is stopped, the brake force BP to be applied to the vehicle is quickly increased when sudden braking is required. Can assist.

  (4) Moreover, in the vehicle brake device 11 of the present embodiment, when the pitching suppression assist control is terminated at the second timing t12 (step S24), the sudden brake assist control is started (step S25). Then, contrary to the time before the second timing t12, the reaction force X applied to the brake pedal 12 from the reaction force generator 20 is reduced. The decreasing speed of the reaction force X at this time is larger than the increasing speed of the reaction force X during the execution of the pitching suppression auxiliary control. As the reaction force X is thus reduced, the assist effect of increasing the brake operation amount BIN can be further enhanced. Therefore, the brake operation amount BIN can be increased early. As a result, the increasing speed of the WC pressure in the wheel cylinder 101 can be increased, and as a result, the braking force BP applied to the vehicle is increased early. Therefore, it is possible to favorably assist the sudden braking of the vehicle.

  If it is determined at the subsequent fourth timing t14 that the vehicle has stopped (step S26: YES), the sudden brake assist control is terminated. Then, the reduction of the reaction force X applied from the reaction force generator 20 to the brake pedal 12 is stopped.

  (5) Note that the sudden braking execution condition may not be satisfied during the execution of the pitching suppression assist control (step S23: NO). In this case, as indicated by a broken line in FIG. 4C, the pitching suppression assist control is continued until the third timing t13 when the vehicle body speed VS of the vehicle becomes equal to the determination speed VSTH3 immediately before stop. Since it is determined at the third timing t13 that the vehicle is about to stop (step S27: YES), the pitching suppression auxiliary control is ended (step S28), and the vehicle stop time control is started (step S29). .

  Then, as indicated by a broken line in FIG. 4C, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 is reduced after the third timing t13. The decreasing speed of the reaction force X at this time is smaller than the decreasing speed of the reaction force X when the sudden brake assist control is performed. Therefore, as indicated by a broken line in FIG. 4B, the brake operation amount BIN is slowly increased as the reaction force X decreases. As a result, the braking force BP applied to the vehicle is also gradually increased. Therefore, when the vehicle is stopped, the vehicle can be surely stopped while suppressing the pitching of the vehicle.

  (6) Here, the advanced driver who is a good driver of the vehicle decreases the brake operation amount BIN during the transition period by his / her own intention in order to suppress the pitching when the vehicle is stopped. Reduce the deceleration of. Then, the advanced driver who has decreased the brake operation amount BIN during the transition period increases the brake operation amount BIN immediately before stopping the vehicle at his / her will and reliably stops the vehicle.

  In the vehicle brake device 11 according to the present embodiment, the driver performs the pitching suppression assist control and the sudden brake assist control by increasing the change speed of the reaction force X applied from the reaction force generator 20 to the brake pedal 12. Can be recognized. As a result, the driver can experience a brake operation as performed by an advanced driver. And it becomes possible to improve a driver | operator's brake operation skill through such experience.

The above embodiment may be changed to another embodiment as described below.
When changing the pitching suppression assist control or the sudden brake assist control, the changing speed of the reaction force X applied from the reaction force generator 20 to the brake pedal 12 may be reduced. By reducing the change speed of the reaction force X in this way, the operation feeling of the brake pedal 12 accompanying the execution of the pitching suppression assist control and the sudden brake assist control is less likely to change. Thereby, it is possible to make it difficult for the driver to feel uncomfortable due to the change in the operation feeling of the brake pedal 12.

  In addition, when decreasing the increase speed of the reaction force X at the time of execution of the pitching suppression auxiliary control, the pitching suppression auxiliary control is performed earlier than in the case where the increase speed of the reaction force X is large as in the above embodiment. It is preferable to start.

  Even when the pitching suppression assist control is being performed, if the brake operation amount BIN is increased by the driver, the brake force BP applied to the vehicle is increased. For this reason, when the vehicle is about to stop while the pitching suppression assist control is being performed, the vehicle stop control need not be performed. When the vehicle stop control is not performed as described above, when it is determined that the vehicle is immediately before the stop, the implementation of the pitching suppression assist control may be terminated or the pitching suppression assist control may be continued. . Further, the pitching suppression assist control may be continued until the vehicle stops, and the pitching suppression assist control may be terminated when the vehicle stops.

  When the sudden brake assist control is performed, the rate of decrease in the reaction force X applied from the reaction force generator 20 to the brake pedal 12 may be variable depending on the situation. For example, the decreasing speed of the reaction force X may be increased as the vehicle body speed VS of the vehicle at the time when the sudden braking execution condition is satisfied. Further, the rate of decrease in the reaction force X may be increased as the relative vehicle body speed of the host vehicle relative to the vehicle speed of the preceding vehicle at the time when the sudden braking execution condition is satisfied.

  The ratio of the increase amount of the WC pressure to the increase amount of the brake operation amount BIN may be changed between a normal brake operation and a sudden brake. For example, the above ratio when the sudden brake assist control is performed may be larger than the above ratio during normal brake operation. In this case, when the brake operation amount BIN is increased when the sudden brake assist control is performed, the increasing speed of the braking force BP applied to the vehicle can be further increased.

  In the above embodiment, when the sudden braking execution condition is satisfied during the execution of the pitching suppression assist control, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 is reduced by the sudden brake assist control. However, even if the execution condition is satisfied, the sudden brake assist control may not be performed. According to this configuration, the increase in the reaction force X is stopped by terminating the pitching suppression assist control when the execution condition is satisfied. That is, the reaction force X is held at the magnitude when the execution condition is satisfied. Therefore, the increase in the brake operation amount BIN can be assisted as compared with the case where the increase in the reaction force X is continued even when a sudden brake is required. Therefore, even when the braking force BP to be applied to the vehicle is reduced so as to suppress the pitching when the vehicle is stopped, the brake force BP to be applied to the vehicle is quickly increased when sudden braking is required. Increase can be assisted.

  As a method for determining whether or not the sudden braking execution condition is satisfied based on the change in the brake operation amount BIN, a determination method other than the determination method described in the above embodiment may be employed. For example, when the increase speed of the brake operation amount BIN during execution of the pitching suppression assist control is large, it is determined that the operating force of the brake pedal 12 by the driver is increased, and the driver is requesting sudden braking. Can do. Therefore, when the increasing speed of the brake operation amount BIN during the execution of the pitching suppression assist control is equal to or higher than the specified speed, it may be determined that the sudden braking execution condition is satisfied.

  -If the vehicle is equipped with a monitoring device such as a camera or sensor that can monitor the front of the vehicle, the distance from the host vehicle to the preceding vehicle is determined by the camera or sensor provided on the vehicle. You may make it judge that the implementation condition of sudden braking was satisfied when it is detected that it is extremely short, or the obstacle suddenly appeared in front of the own vehicle. In this case, when the execution condition of the sudden braking is satisfied based on the monitoring result of the camera, the sensor, etc. during the execution of the pitching suppression auxiliary control, the execution of the pitching suppression auxiliary control is terminated and the sudden brake auxiliary control is started. It becomes.

  When the pitching suppression assist control is performed, the increasing speed of the reaction force X applied from the reaction force generator 20 to the brake pedal 12 may be variable depending on the situation. For example, as the vehicle body speed VS at the start of the brake operation increases, the ground load on the front wheels of the vehicle tends to increase and pitching tends to occur. Therefore, the increasing speed of the reaction force X may be increased as the vehicle body speed VS of the vehicle at the start of the brake operation increases. In addition, pitching is more likely to occur when the vehicle stops as the deceleration of the vehicle at the time when the starting condition for the pitching suppression assist control is satisfied is larger. Therefore, the increasing speed of the reaction force X may be increased as the deceleration of the vehicle at the time when the starting condition for the pitching suppression assist control is satisfied. Further, the increasing speed of the reaction force X may be changed depending on the slope of the road surface on which the vehicle travels, the friction coefficient, or the like.

When executing the pitching suppression assist control, the reaction force X applied from the reaction force generator 20 to the brake pedal 12 may be increased stepwise.
The ratio of the increase amount of the WC pressure to the increase amount of the brake operation amount BIN may be changed between the normal brake operation and the pitching suppression assist control. For example, the above ratio when the pitching suppression assist control is performed may be larger or smaller than the above ratio during normal brake operation.

  The transition determination speed VSTH1, which is a determination value for determining whether or not the transition period has been reached, may be a fixed value or a variable value. When the transition determination speed VSTH1 is a variable value, for example, the transition determination speed VSTH1 may be changed according to the gradient of the road surface on which the vehicle travels and the friction coefficient.

  In the above embodiment, the reaction force X applied to the brake pedal 12 is adjusted by adjusting the hydraulic pressure in the stroke simulator 21, but the reaction force X may be adjusted by other methods. For example, the reaction force generator may be an apparatus that adjusts the reaction force X by providing an actuator such as a motor that applies an axial force to the piston 22 and controlling the drive of the actuator.

  The vehicle brake device may be a device other than the device described in the above embodiment as long as it includes a reaction force generator.

  DESCRIPTION OF SYMBOLS 11 ... Brake device of vehicle, 12 ... Brake pedal which is an example of brake operation member, 20 ... Reaction force generator, 50 ... Control device, BIN ... Brake operation amount, BP ... Brake force, X ... Reaction force

Claims (5)

When the brake operation amount is the operation amount the brake operating member is increased to increase the braking force applied to the vehicle, the brake system of a vehicle to reduce the braking force applied to the vehicle when the brake operation quantity is decreased Because
A reaction force generator for adjusting a reaction force applied to the brake operation member;
Pitching that increases the reaction force applied from the reaction force generator to the brake operation member during the transition from a state where the vehicle decelerates to a state where the vehicle stops in a situation where a braking force is applied to the vehicle A control device that performs the suppression assist control,
The control device increases the braking force applied to the vehicle when the brake operation amount is increased, and applies the vehicle to the vehicle when the brake operation amount is decreased when the pitching suppression auxiliary control is being performed. The brake force applied to the vehicle is not changed when the brake operation amount is not changed.
The control device terminates the execution of the pitching suppression auxiliary control when a sudden brake execution condition is satisfied during the execution of the pitching suppression auxiliary control. The control device changes the ratio of the increase amount of the brake force to the increase amount of the brake operation amount between when the pitching suppression auxiliary control is performed and when the pitching suppression auxiliary control is not performed.
The brake device for a vehicle according to claim 1. When the sudden braking execution condition is satisfied during the execution of the pitching suppression assist control, the control device ends the execution of the pitching suppression assist control and the reaction force applied from the reaction force generator to the brake operation member. The brake device for a vehicle according to claim 1 or 2 , wherein sudden brake auxiliary control for reducing force is performed. The control device increases the ratio of the increase amount of the brake force to the increase amount of the brake operation amount when the sudden brake assist control is performed than when the sudden brake assist control is not performed.
The vehicle brake device according to claim 3. 5. The vehicle according to claim 1 , wherein, in the pitching suppression assist control, the control device gradually increases a reaction force applied from the reaction force generation device to the brake operation member. Brake device.