JP2008100644A - Vehicular braking control device, and vehicular braking control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular braking control device, and a vehicular braking control method capable of suppressing generation of abnormal noise from a wheel side to which the braking power is given when the braking power is given to the wheel while a vehicle travels. <P>SOLUTION: An ECU of a vehicular braking control device sets a rear wheel (for example, a right rear wheel) on the inner side of the turning direction of a vehicle to be a wheel for braking when the absolute value of the steering angle A of a steering wheel is not less than the steering angle threshold KA, and executes the braking control during the turn for giving the braking power to the wheel for braking. The ECU controls a braking power giving mechanism so that the magnitude of the braking power BP to the wheel for braking (for example, the right rear wheel) is fluctuated with a predetermined amplitude when the vehicular speed of the vehicle is not higher than the vehicular speed threshold KVS2 for starting the fluctuation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle braking control device and a vehicle braking control method for applying a braking force to each wheel of the vehicle.

  Conventionally, as a vehicle braking control device for applying a braking force to at least one of the wheels during traveling of the vehicle, for example, a vehicle braking control device described in Patent Document 1 (hereinafter referred to as “conventional braking control device”). ") Has been proposed. This conventional braking control device is a device for reducing the turning radius of a turning vehicle, and determines that the steering wheel has been steered to the maximum when the steering angle of the steering wheel is greater than or equal to a preset steering angle threshold. I am doing so. “Maximum steering” refers to a state in which the steering wheel is steered to the maximum in a certain direction (right or left in the rotational direction).

When the conventional braking control device determines that the steering wheel has been steered to the maximum, the rear wheel inside the turning direction of the vehicle (the right rear wheel when turning right) is set as the braking wheel, A braking control during turning for applying a braking force of a certain magnitude to the braking wheel is executed. For this reason, when the vehicle is turning, the turning radius control can be performed, so that the turning radius can be reduced as compared with a vehicle that does not execute the turning time braking control.
JP-A-8-207823 (Claim 1)

  By the way, when a braking force of a certain magnitude is continuously applied to a braking wheel (a rear wheel inside the turning direction of the vehicle) when the vehicle is running, such as when the above-described turning braking control is performed, the wheel cylinder When the friction material attached to the brake member applies a frictional force to the friction material attached to the braking wheel, the friction materials sometimes resonate with each other. And when this state was continued, there was a possibility that abnormal noise (so-called resonance noise) generated from the braking wheel side would gradually increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an abnormal noise from the wheel side to which the braking force is applied when the braking force is applied to the wheel while the vehicle is running. It is an object of the present invention to provide a vehicle brake control device and a vehicle brake control method that can suppress the occurrence of the vehicle.

  In order to achieve the above object, the invention according to claim 1 relating to a braking control device for a vehicle includes wheels (FR, FL, RR, RL) disposed on the left and right sides with respect to the traveling direction of the vehicle, and the wheels. (FR, FL, RR, RL) A vehicle braking control device (11) mounted on a vehicle including a braking force applying mechanism (15) that is driven when applying a braking force to each wheel ( Control means (16) for controlling the braking force applying mechanism (15) when applying a braking force (BP) to at least one wheel (RR) of FR, FL, RR, RL), the control means (16) is the braking force (BP) when a braking force (BP) is applied to at least one of the wheels (FR, FL, RR, RL) during travel of the vehicle. For braking the wheel (RR) to which And the braking force applying mechanism (15) is controlled so as to vary the magnitude of the braking force (BP) with respect to the braking wheel (RR) with a preset predetermined amplitude (KBP). .

  Generally, when a braking force is applied to a braking wheel while the vehicle is traveling, there is a possibility that an abnormal noise (resonance noise) may be generated from the braking wheel side depending on the magnitude of the braking force. Therefore, in the present invention, the range of the magnitude of the braking force at which abnormal noise can be generated from the braking wheel side is examined in advance through experiments or the like, and the braking force applied to the braking wheel with an amplitude greater than the range of the magnitude of the braking force. A predetermined amplitude is set so as to vary the magnitude. By setting the predetermined amplitude in this way, compared to the case where the magnitude of the braking force on the braking wheel is not changed, the member (friction material) that applies the braking force to the braking wheel and the braking wheel are attached. It is possible to shorten the time during which the formed member (friction material) resonates. Therefore, when a braking force is applied to the wheel while the vehicle is running, it is possible to suppress the generation of abnormal noise from the wheel side to which the braking force is applied.

  According to a second aspect of the present invention, in the vehicle braking control apparatus according to the first aspect, the control means (16) is configured to increase a braking force (BP) applied to the braking wheel (RR) when the vehicle is traveling. The gist of the present invention is to control the braking force applying mechanism (15) so that the fluctuation cycle becomes a predetermined cycle (KC) set in advance.

  In the above configuration, when the predetermined period is set corresponding to the response speed of the braking force application mechanism, a member (friction material) for applying braking force to the braking wheel and a member (friction material) attached to the braking wheel. ) Can be shortened as much as possible. Therefore, the generation of abnormal noise from the braking wheel side is satisfactorily suppressed while sufficiently securing the braking force on the braking wheel.

  According to a third aspect of the present invention, in the vehicle braking control device according to the first or second aspect, the vehicle control apparatus further comprises a vehicle body speed calculating means (S12) for calculating a vehicle body speed (VS) of the vehicle. (16) is the braking wheel when the vehicle speed (VS) calculated by the vehicle speed calculation means (S12) is less than a preset vehicle speed threshold (KVS2) when the vehicle is running. The gist is to control the braking force applying mechanism (15) so as to vary the magnitude of the braking force (BP) with respect to (RR) with the predetermined amplitude (KBP).

  In the above configuration, when the vehicle is traveling at a vehicle body speed equal to or higher than the vehicle body speed threshold, even if a braking force is applied to the braking wheel of the vehicle, abnormal noise is hardly generated from the braking wheel side. Absent. Even if abnormal noise is generated from the braking wheel side, noise (road noise, etc.) during driving of the vehicle is large, so abnormal noise from the braking wheel side is I don't care much compared to the noise at the time. Therefore, in such a case, the braking force for the braking wheel is not changed. Therefore, it is possible to vary the braking force applied to the braking wheel only when the vehicle is traveling at a low speed (body speed less than the vehicle speed) at which abnormal noise from the braking wheel side is relatively large. Become.

  According to a fourth aspect of the present invention, in the vehicle braking control apparatus according to any one of the first to third aspects, a steering angle calculation for calculating a steering angle (A) of the steering (24) of the vehicle. Means (S14), wherein the control means (16) has an absolute value of the steering angle (A) calculated by the steering angle calculation means (S14) equal to or greater than a preset steering angle threshold (KA). In some cases, the wheel (RR) on the inner side in the turning direction of the vehicle is set as the braking wheel, and the magnitude of the braking force (BP) applied to the braking wheel (RR) is changed with the predetermined amplitude (KBP). The gist is to control the braking force applying mechanism (15).

  In the above-described configuration, the magnitude of the braking force applied to the wheels on the inner side in the turning direction of the vehicle is varied during execution of so-called turning braking control for applying a braking force to the wheels on the inner side in the turning direction of the turning vehicle. That is, when executing a control that applies a braking force to the braking wheel for a relatively long time, such as when executing a braking control during turning, the magnitude of the braking force applied to the wheel inside the turning direction of the vehicle varies. Is effective. Therefore, the occurrence of abnormal noise from the braking wheel (wheel inside the turning direction of the vehicle) during the turning of the vehicle is well suppressed.

  On the other hand, the invention according to claim 5 according to the vehicle braking control method is a vehicle that controls the braking force applied to the wheels (FR, FL, RR, RL) disposed on the left and right sides of the traveling direction of the vehicle. In the braking control method, when a braking force (BP) is applied to at least one wheel (RR) among the wheels (FR, FL, RR, RL) during travel of the vehicle, the braking force (BP) The wheel (RR) to which BP) is applied is set as a braking wheel, and the magnitude of the braking force (BP) with respect to the braking wheel (RR) is varied with a predetermined amplitude (KBP) set in advance. The summary is as follows.

  With the above configuration, the same effect as that of the first aspect of the invention can be achieved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a vehicle braking control device and a vehicle braking control method according to the invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle). Unless otherwise specified, the left-right direction in the following description is the same as the left-right direction in the vehicle traveling direction.

  As shown in FIG. 1, the vehicle braking control device 11 according to the present embodiment includes a plurality of (four in the present embodiment) wheels (right front wheel FR, left front wheel FL, right rear wheel RR, and left rear wheel RL). Of these, the front wheels FR and FL are mounted on a vehicle (so-called front wheel drive vehicle) that functions as drive wheels. This vehicle includes a driving force transmission mechanism 13 that transmits driving force generated by an engine 12 serving as a driving source to front wheels FR and FL, and front wheel steering for turning the front wheels FR and FL as steered wheels (steering wheels). A mechanism 14 and a braking force application mechanism 15 for applying a braking force to each wheel FL, FR, RL, RR are provided. The vehicle also includes an electronic control unit (hereinafter referred to as “ECU”) 16 as a control means for appropriately controlling each of the mechanisms 13, 14, and 15 according to the traveling state of the vehicle. Constitutes the braking control device 11. The engine 12 generates a driving force corresponding to the depression operation of the accelerator pedal 17 by the driver of the vehicle.

  The driving force transmission mechanism 13 is provided with a transmission 18 connected to the output shaft of the engine 12 and a front wheel differential gear 19 for appropriately distributing the driving force transmitted from the transmission 18 and transmitting it to the front wheels FL and FR. It has been. An intake passage 20a in the intake pipe 20 extending outward from the engine 12 is provided with a throttle valve 21 for varying the opening cross-sectional area, and outside the intake pipe 20, a throttle valve 21 is provided. A throttle valve actuator (for example, a DC motor) 22 for controlling the opening is provided. A fuel injection device 23 having an injector for injecting fuel is provided in the vicinity of an intake port (not shown) of the engine 12. In the vicinity of the accelerator pedal 17, an accelerator opening sensor SE1 is provided for detecting the amount of depression (opening) of the accelerator pedal 17 by the driver.

  The front wheel steering mechanism 14 is provided with a steering wheel 24, a steering shaft 25 to which the steering wheel 24 is fixed, and a steering actuator 26 connected to the steering shaft 25. Further, the front wheel steering mechanism 14 is provided with a link mechanism portion 27 including a tie rod that can be moved in the left-right direction of the vehicle by a steering actuator 26 and a link that steers the front wheels FL and FR by the movement of the tie rod. It has been. Further, the front wheel steering mechanism 14 is provided with a steering angle sensor SE2 for detecting the steering angle of the steering wheel 24 and a steering torque sensor SE3 for detecting the steering torque applied to the steering wheel 24.

Next, the braking force application mechanism 15 will be described with reference to FIG.
As shown in FIG. 2, the braking force applying mechanism 15 of the present embodiment includes a hydraulic pressure generating device 32 having a master cylinder 30 and a booster 31, and a hydraulic pressure control device having two hydraulic pressure circuits 33 and 34 (FIG. 2). Is shown by a two-dot chain line). The hydraulic circuits 33 and 34 are connected to the hydraulic pressure generator 32 and are connected to wheel cylinders 36a, 36b, 36c, and 36d provided corresponding to the wheels FR, FL, RR, and RL. . That is, the wheel cylinder 36a corresponds to the right front wheel FR, and the wheel cylinder 36b corresponds to the left front wheel FL. Further, the wheel cylinder 36c corresponds to the right rear wheel RR, and the wheel cylinder 36d corresponds to the left rear wheel RL.

  The hydraulic pressure generating device 32 is provided with a brake pedal 37, and the master cylinder 30 and the booster 31 of the hydraulic pressure generating device 32 are driven based on the brake pedal 37 being depressed by the driver of the vehicle. It has become. The master cylinder 30 is provided with two output ports 30a and 30b. The first hydraulic circuit 33 is connected to the output port 30a, and the second hydraulic circuit 34 is connected to the output port 30b. Further, the hydraulic pressure generating device 32 is provided with a brake switch SW1 electrically connected to the ECU 16, and a signal corresponding to the operation state of the brake pedal 37 is output from the brake switch SW1 to the ECU 16.

  The hydraulic pressure control device 35 includes a pump 38 for increasing the brake hydraulic pressure in the first hydraulic pressure circuit 33, a pump 39 for increasing the brake hydraulic pressure in the second hydraulic pressure circuit 34, and each pump. A motor M for driving the motors 38 and 39 at the same time is provided. In addition, reservoirs 40 and 41 for storing brake fluid are provided on the hydraulic circuits 33 and 34, and the brake fluid in the reservoirs 40 and 41 is driven by the pumps 38 and 39. , 34 are supplied.

  The first hydraulic circuit 33 includes a left front wheel path 33a for the wheel cylinder 36b (for the left front wheel FL) connected to the wheel cylinder 36b corresponding to the left front wheel FL, and a wheel cylinder 36c corresponding to the right rear wheel RR. And a right rear wheel path 33b for the wheel cylinder 36c (for the right rear wheel RR) connected to the. On each of the paths 33a and 33b, normally open proportional solenoid valves 42 and 43 and normally closed solenoid valves 46 and 47 are provided, respectively.

  Similarly, the second hydraulic circuit 34 corresponds to the right front wheel path 34a for the wheel cylinder 36a (for the right front wheel FR) connected to the wheel cylinder 36a corresponding to the right front wheel FR, and the left rear wheel RL. A left rear wheel path 34b for the wheel cylinder 36d (for the left rear wheel RL) connected to the wheel cylinder 36d is formed. On each of the paths 34a and 34b, normally open proportional solenoid valves 44 and 45 and normally closed solenoid valves 48 and 49 are respectively provided.

  In addition, a normally open proportional solenoid valve 50 is connected to the master cylinder 30 side of the first hydraulic circuit 33 with respect to the portions branched into the paths 33a and 33b, and in parallel with the proportional solenoid valve 50. A relief valve 51 is connected. The proportional solenoid valve 50 and the relief valve 51 constitute a proportional differential pressure valve 52. The proportional differential pressure valve 52 can generate a hydraulic pressure difference (brake hydraulic pressure difference) on the master cylinder 30 side and the wheel cylinders 36b and 36c side from the proportional differential pressure valve 52 based on control by the ECU 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 51 a constituting the relief valve 51. Further, the first hydraulic circuit 33 is formed with a branch hydraulic pressure path 33c branched from the reservoir 40 and the pump 38 toward the master cylinder 30 side, and on the branch hydraulic pressure path 33c, A normally closed electromagnetic valve 53 is connected.

  Similarly, a normally open proportional solenoid valve 54 is connected to the master cylinder 30 side of the second hydraulic circuit 34 that is branched to the paths 34 a and 34 b, and in parallel with the proportional solenoid valve 54. A relief valve 55 is connected. The proportional solenoid valve 54 and the relief valve 55 constitute a proportional differential pressure valve 56. The proportional differential pressure valve 56 can generate a hydraulic pressure difference (brake hydraulic pressure difference) between the master cylinder 30 side and the wheel cylinders 36a and 36d side with respect to the proportional differential pressure valve 56 based on control by the ECU 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 55a constituting the relief valve 55. Further, the second hydraulic pressure circuit 34 is formed with a branch hydraulic pressure path 34c branched from the reservoir 41 and the pump 39 toward the master cylinder 30 side, and on the branch hydraulic pressure path 34c. A normally closed electromagnetic valve 57 is connected.

  Here, changes in the brake fluid pressure in the wheel cylinders 36a to 36d when the solenoid coils of the solenoid valves 42 to 49 are in an energized state and in a non-energized state will be described. In the following description, it is assumed that the proportional solenoid valves 50 and 54 are closed and the solenoid valves 53 and 57 on the branch hydraulic pressure paths 33c and 34c are open.

  First, when all the solenoid coils of the solenoid valves 42 to 49 are in a non-energized state, the normally open type proportional solenoid valves 42 to 45 remain open and the normally closed type solenoid valves 46 to 49. Remains closed. Therefore, when the pumps 38 and 39 are driven, the brake fluid in the reservoirs 40 and 41 flows into the wheel cylinders 36a to 36d via the paths 33a, 33b, 34a and 34b, and the wheels The brake fluid pressure in the cylinders 36a to 36d will increase.

  On the other hand, when only the solenoid coils of the normally open proportional solenoid valves 42 to 45 among the solenoid valves 42 to 49 are energized, all the solenoid valves 42 to 49 are closed. Therefore, the flow of brake fluid through each path 33a, 33b, 34a, 34b is restricted, so that the brake fluid pressure in each wheel cylinder 36a-36d is maintained at its fluid pressure level.

  When all the solenoid coils of the solenoid valves 42 to 49 are energized, the normally open proportional solenoid valves 42 to 45 are closed and the normally closed solenoid valves 46 to 49 are opened. It becomes. Therefore, the brake fluid flows out from the wheel cylinders 36a to 36d to the reservoirs 40 and 41 through the paths 33a, 33b, 34a and 34b, and the brake fluid pressure in the wheel cylinders 36a to 36d drops. Become.

  As shown in FIG. 1, the ECU 16 mainly includes a digital computer including a CPU 60, a ROM 61, a RAM 62, and the like, and a drive circuit (not shown) for driving each device. The ROM 61 stores various control programs for controlling the driving force transmission mechanism 13, the front wheel steering mechanism 14, and the braking force application mechanism 15 (hydraulic pressure control device 35), and various threshold values (a vehicle speed threshold value for starting control described later). , A vehicle start speed threshold value for variation, a steering angle threshold value, and the like) are stored. The RAM 62 stores various information that can be appropriately rewritten while the vehicle is being driven.

  Further, the input side interface (not shown) of the ECU 16 detects the wheel speeds of the brake switch SW1, the accelerator opening sensor SE1, the steering angle sensor SE2, the steering torque sensor SE3, and the wheels FR, FL, RR, and RL. Wheel speed sensors SE4, SE5, SE6, and SE7 are connected. Further, the input side interface is “ON” when the vehicle body acceleration sensor (also referred to as “front / rear G sensor”) SE8 for detecting the vehicle body acceleration in the front-rear direction of the vehicle, and when turning braking control described later is executed. The operation switch SW2 set to is connected.

  The steering angle sensor SE2 outputs a signal indicating that the ECU 16 indicates a positive value when the steering wheel 24 is steered to the right in the rotational direction, while the ECU 16 is negative when the steering wheel 24 is steered to the left in the rotational direction. It is set to output a signal indicating the value of. The vehicle body acceleration sensor SE8 outputs a signal such that the ECU 16 indicates a positive value when the vehicle accelerates, and outputs a signal such that the ECU 16 indicates a negative value when the vehicle decelerates. Is set to

  On the other hand, an output side interface (not shown) of the ECU 16 is connected to a motor M for driving the pumps 38 and 39 and the electromagnetic valves 42 to 50, 53, 54 and 57. The ECU 16 individually controls the operation of the motor M and the electromagnetic valves 42 to 50, 53, 54, and 57 based on the input signals from the brake switch SW1 and the various sensors SE1 to SE8. .

  Next, the turning-time braking control execution determination processing routine executed by the ECU 16 of the present embodiment will be described below based on the flowchart shown in FIG. 3 and the timing charts shown in FIGS. 4 and 5.

  The ECU 16 executes a turning braking control execution determination processing routine at predetermined intervals (for example, every “0.01” seconds). In this turning braking control execution determination processing routine, the ECU 16 determines whether or not the input signal from the brake switch SW1 is “OFF” (step S10). That is, the ECU 16 determines whether or not the brake pedal 37 is not depressed. If the determination result of step S10 is negative (SW1 = “ON”), the ECU 16 proceeds to step S21 to be described later.

  On the other hand, if the determination result in step S10 is affirmative (SW1 = “OFF”), the ECU 16 determines each wheel based on the input signals from the wheel speed sensors SE4 to SE7 of the wheels FR, FL, RR, RL. The wheel speeds VW of FR, FL, RR, RL are detected by calculation (step S11). Subsequently, the ECU 16 detects the vehicle body speed VS by calculation based on the wheel speed VW of each wheel FR, FL, RR, RL detected in step S11 (step S12). That is, the ECU 16 sets the vehicle body speed VS on the basis of the larger value of the wheel speeds VW of the front wheels FR and FL that are drive wheels. Therefore, in this point, in this embodiment, the ECU 16 also functions as a vehicle body speed calculation unit.

  Then, the ECU 16 determines whether or not the absolute value of the vehicle body speed VS detected in step S12 is equal to or less than a preset vehicle start speed threshold value KVS1 (for example, “10” km per hour) (step S13). ). The control start vehicle body speed threshold value KVS1 is an upper limit value of the vehicle body speed at which the effect of the braking control during turning described later can be satisfactorily achieved, and is set in advance by experiments or simulations.

  If the determination result in step S13 is negative (VS absolute value> KVS1), the ECU 16 proceeds to step S21 described later. On the other hand, if the determination result in step S13 is affirmative (VS absolute value ≦ KVS1), the ECU 16 detects the steering angle A of the steering wheel 24 by calculation based on the input signal from the steering angle sensor SE2 (step S13). S14). In this regard, in the present embodiment, the ECU 16 also functions as a steering angle calculation unit.

  Subsequently, the ECU 16 determines whether or not the absolute value of the steering angle A detected in step S14 is equal to or greater than a preset steering angle threshold KA (step S15). This steering angle threshold KA is set to the absolute value of the maximum steering angle of the steering wheel 24 of the present embodiment. The maximum steering angle means a state in which the steering wheel 24 is steered to the maximum in a certain direction (right side or left side in the rotation direction).

  If the determination result in step S15 is negative (A absolute value <KA), the ECU 16 proceeds to step S21 to be described later. On the other hand, if the determination result in step S15 is affirmative (A absolute value ≧ KA), the ECU 16 determines whether or not the operation switch SW2 is set to “ON” (step S16). If this determination result is a negative determination (SW2 = “OFF”), the ECU 16 proceeds to step S21 to be described later.

  On the other hand, when the determination result of step S16 is affirmative (SW2 = “ON”), the ECU 16 performs a braking control during turning to reduce the turning determination of the vehicle (that is, to turn the vehicle slightly) (step S16). S17). In the execution of the braking control during turning, first, the ECU 16 specifies the rear wheel inside the turning direction of the vehicle based on the steering angle A of the steering wheel 24 detected in step S14. That is, when the steering angle A detected in step S14 is a positive value, the ECU 16 identifies the right rear wheel RR as the rear wheel inside the turning direction of the vehicle, while the steering angle A is a negative value. If there is, the left rear wheel RL is identified as the rear wheel inside the turning direction of the vehicle. Subsequently, the ECU 16 sets the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the specified vehicle as a braking wheel, and applies a braking force having a predetermined magnitude to the braking wheel (see FIG. In order to apply the normal braking force BP1) indicated by 4, the driving of the braking force applying mechanism 15 is controlled.

  Specifically, the ECU 16 supplies current to the solenoids of the proportional solenoid valves 42, 44, 45, 50, and 54 in order to close the proportional solenoid valves 42, 44, 45, 50, and 54, respectively. Further, the ECU 16 supplies a current to the solenoid of the electromagnetic valve 53 so as to open the electromagnetic valve 53. Then, the ECU 16 drives the motor M to drive the pump 38. Then, as shown in FIG. 4, the braking force BP (= BP1) is applied to the wheel inside the turning direction of the vehicle (for example, the right rear wheel RR), and the vehicle is controlled by the wheel inside the turning direction of the vehicle. It turns (runs) in a state where the power BP is applied.

  Subsequently, the ECU 16 determines whether or not the vehicle body speed VS detected in step S12 is equal to or lower than a preset vehicle start speed threshold value KVS2 (for example, “8” km / hour) (step S18). This fluctuation start vehicle body speed threshold value KVS2 determines whether or not the magnitude of the braking force BP applied to the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle is changed during execution of the braking control during turning. This value is set in advance through experiments or simulations. When braking control is executed for a vehicle that is turning at a vehicle body speed VS that is equal to or less than the vehicle body speed threshold value KVS2 for variation start, from the rear wheel (for example, the right rear wheel RR) side inside the vehicle turning direction, When the normal braking force BP1 is applied to the rear wheel (for example, the right rear wheel RR), there is a possibility that an abnormal noise (resonance noise) is generated.

  If the determination result in step S18 is negative (VS absolute value> KVS2), the ECU 16 changes the braking force BP of the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle as will be described later. Without executing the control, the turning braking control execution determination processing routine is terminated. On the other hand, when the determination result in step S18 is affirmative (VS absolute value ≦ KVS2), the ECU 16 applies the braking force applied to the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle, which is a braking wheel. The fluctuation condition of BP is read from the ROM 61 (step S19). That is, the ROM 61 stores a predetermined amplitude KBP (“0.5” nPa (nanopascal) to “3” μPa (micropascal), which is a fluctuation amount of the magnitude of the braking force BP (that is, the brake fluid pressure in the wheel cylinder). ) And a predetermined cycle KC (an arbitrary value between “5” Hz and “5” kHz), which is a fluctuation cycle of the braking force BP, is stored in advance (see FIG. 4). .

  Here, when applying braking force to the wheels FR, FL, RR, RL, the friction material (not shown) attached to the wheel cylinders 36a to 36d is attached to the wheels FR, FL, RR, RL. The friction material (not shown) is brought into pressure contact. For example, in the case of a drum type brake, a brake shoe with a friction material (also referred to as “lining”) is pressed against the inside of the drum rotating with the wheels FR, FL, RR, and RL (wheels). The braking force is applied to the wheels FR, FL, RR, and RL by the frictional force generated at that time.

  As described above, when the braking force is applied to the wheels FR, FL, RR, and RL, the brake fluid pressure in the wheel cylinders 36a to 36d (that is, the braking force applied to the wheels FR, FL, RR, and RL). Depending on the magnitude of the power BP), there is a possibility that the friction materials pressed against each other may resonate. As a result, an abnormal sound (resonance sound) accompanying resonance is generated from the wheel (braking wheel) side to which the braking force BP is applied. Therefore, in the present embodiment, the lower limit value and the upper limit value of the magnitude of the braking force BP that can resonate between the friction materials that are in pressure contact with each other are examined in advance by experiments, simulations, and the like, and the difference between the lower limit value and the upper limit value is greater than or equal to. The predetermined amplitude KBP is set so that the braking force BP varies.

  Further, in this embodiment, in order to periodically execute the fluctuation of the braking force BP for the braking wheel (for example, the right rear wheel RR) during the turning braking control, the proportional electromagnetic that is driven when such control is performed. The response speeds of the valves 50 and 54 are examined in advance through experiments, simulations, and the like. Then, the predetermined period KC is set so that the braking force BP varies most finely within the range in which the proportional solenoid valves 50 and 54 can respond. Note that the predetermined period KC includes noise generated due to the drive of the proportional solenoid valve (for example, the proportional solenoid valve 50) when the magnitude of the braking force BP for the braking wheel (for example, the right rear wheel RR) is varied. More preferably, it is set so as to be avoided.

  Then, the ECU 16 causes the braking force applying mechanism 15 to execute variation start control so as to vary the braking force BP for the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle (step S20). The braking control execution determination processing routine is terminated. In other words, the ECU 16 performs the proportional solenoid valve (for example, the proportional solenoid valve 50) of the braking force applying mechanism 15 in a state where the braking force BP for the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle becomes the normal braking force BP1. ).

  Here, the ECU 16 maintains the proportional solenoid valve (for example, the proportional solenoid valve 50) in the closed state, whereby the brake fluid in the wheel cylinder (for example, the wheel cylinder 36c) corresponding to the braking wheel (for example, the right rear wheel RR). The pressure is increased. As a result, the braking force BP for the braking wheel (for example, the right rear wheel RR) increases. On the other hand, the ECU 16 gradually decreases the current supplied to the solenoid of the proportional solenoid valve (for example, the proportional solenoid valve 50) in the closed state, so that the proportional solenoid valve (for example, the proportional solenoid valve 50) gradually increases from the closed state. Migrate and open. Then, the brake fluid in the wheel cylinder (for example, the wheel cylinder 36c) flows backward in the right rear wheel path 33b toward the master cylinder 30, and the brake fluid pressure in the wheel cylinder (for example, the wheel cylinder 36c) gradually decreases. That is, the braking force BP for the braking wheel (for example, the right rear wheel RR) gradually decreases.

  Therefore, in this embodiment, the magnitude of the braking force BP for the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle varies with a predetermined amplitude KBP (“0.5” nPa to “3” μPa). At the same time, the drive speed of the proportional solenoid valve (for example, the proportional solenoid valve 50) is set in advance so as to vary at a predetermined cycle KC ("5" Hz to "5" kPa). Then, the ECU 16 sets a proportional solenoid valve (for example, a proportional solenoid valve) at a preset driving speed in a state where the braking force BP for the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle becomes the normal braking force BP1. 50) is driven. Then, the magnitude of the braking force BP for the rear wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle varies as shown in FIG.

  If the braking force BP for the braking wheel (for example, the right rear wheel RR) is not changed as in the conventional case (that is, when the braking force BP is maintained at the normal braking force BP1), FIG. As shown in a), the abnormal noise (resonance noise) generated from the braking wheel side gradually increases. However, when the braking force BP for the braking wheel (for example, the right rear wheel RR) is changed as in this embodiment, the magnitude of the braking force BP for the braking wheel is as shown in FIG. The time in a region where noise can be generated (specifically, a region having a width of about “0.2” MPa (megapascal)) is much shorter than in the conventional case. Therefore, before the abnormal noise (resonance noise) generated from the braking wheel side becomes large enough to be heard by the vehicle occupant, the generation of the abnormal noise generated from the braking wheel side is avoided. Therefore, it is possible to avoid discomfort to the vehicle occupant due to abnormal noise generated from the braking wheel side when the vehicle turns.

  Further, a region where each friction material resonates (braking force BP) due to wear of the friction material attached to the wheel cylinders 36a to 36d or the friction material attached to the wheels FR, FL, RR, RL due to use over time. May be changed. However, since the magnitude of the braking force BP for the braking wheel (for example, the right rear wheel RR) fluctuates more than the predetermined amplitude KBP, even if the region where the friction materials resonate has changed, the braking wheel side The generation of abnormal noise (resonance sound) from is suppressed satisfactorily.

  In step S21, the ECU 16 ends the braking control during turning when a negative determination is made in any one of the determination processes in steps S10, S13, S15, and S16. Specifically, the ECU 16 stops the supply of current to the solenoids of the electromagnetic valves 42, 44, 45, 50, 53, and 54 and stops the driving of the motor M. Then, the application of the braking force BP to the wheel inside the turning direction of the vehicle (for example, the right rear wheel RR) is stopped (see FIG. 4). Thereafter, the ECU 16 ends the braking control execution determination processing routine during turning.

Therefore, in this embodiment, the following effects can be obtained.
(1) Generally, when a braking force BP is applied to a braking wheel (for example, the right rear wheel RR) when the vehicle is traveling, abnormal noise (resonance sound) may be generated from the braking wheel side depending on the magnitude of the braking force BP. May occur. Therefore, a region in which the friction material attached to the wheel cylinders 36a to 36d and the friction material attached to the wheels FR, FL, RR, RL resonate with each other (region of the magnitude of the braking force BP) is tested in advance. The predetermined amplitude KBP is set so as to be equal to or greater than the width of the region. By changing the magnitude of the braking force BP for the braking wheel (for example, the right rear wheel RR) with the predetermined amplitude KBP, the member (friction part) for applying the braking force BP to the braking wheel and the braking wheel are applied. The time during which the attached member (friction material) resonates can be shortened. Therefore, when the braking force BP is applied to the braking wheel (for example, the right rear wheel RR) while the vehicle is running, it is possible to suppress the generation of abnormal noise from the braking wheel side to which the braking force BP is applied.

  (2) When the predetermined period KC is set corresponding to the response speed of the proportional solenoid valves 50 and 54 provided in the braking force application mechanism 15, the braking force BP is applied to the braking wheel (for example, the right rear wheel RR). The time during which the member (friction material) to be resonated with the member (friction material) attached to the braking wheel can be minimized. Therefore, a sufficient braking force BP for the braking wheel (for example, the right rear wheel RR) can be secured, and the generation of abnormal noise (resonance noise) from the braking wheel side can be satisfactorily suppressed.

  (3) Even when a braking force BP is applied to a braking wheel (for example, the right rear wheel RR) of the vehicle when the vehicle is traveling at a vehicle body speed VS equal to or greater than the vehicle body speed threshold value KVS2 for variation start, There is almost no noise (resonance) from the wheel side. Even if an abnormal noise is generated from the braking wheel (for example, the right rear wheel RR) side, the noise from the traveling wheel side is large for the vehicle occupant because the noise is high when the vehicle travels. Compared to the noise during driving, I don't care much. Therefore, in such a case, the braking force BP for the braking wheel (for example, the right rear wheel RR) is not changed. Therefore, braking is performed only when the vehicle is turning at a low speed (body speed VS less than the fluctuation starting body speed KVS2) at which abnormal noise from the braking wheel (for example, the right rear wheel RR) is relatively large. It is possible to vary the braking force applied to the industrial wheels.

  (4) A braking force BP applied to a wheel on the inner side in the turning direction of the vehicle during execution of so-called turning braking control that applies braking force to a wheel (for example, the right rear wheel RR) on the inner side in the turning direction of the vehicle when the vehicle turns Vary the size of. That is, when the control is performed such that the braking force BP is applied to the braking wheel (for example, the right rear wheel RR) for a relatively long time (for example, about “20” seconds), such as during turning of the vehicle, It is effective to vary the magnitude of the braking force BP with respect to the wheel on the inner side in the turning direction of the vehicle as the wheel. Therefore, it is possible to satisfactorily suppress the generation of abnormal noise from the braking wheels (wheels inside the turning direction of the vehicle) when the vehicle turns.

  (5) In the present embodiment, if the operation switch SW2 is not set to “ON” (that is, step S16 is not affirmative determination), even if steps S10, S13, and S15 are all determined affirmative, The turning braking control is not executed. That is, when the operation switch SW2 is set to “ON” with the intention of causing the vehicle driver to execute the turning braking control, the turning braking control is executed when all of steps S10, S13, and S15 are affirmative. Is done. Therefore, it is possible to prevent the turning-time braking control from being executed even though the driver does not intend to execute the turning-time braking control.

  (6) When the vehicle body speed VS of the vehicle is equal to or higher than the control start vehicle body speed threshold value KVS1, the braking control during turning is executed even if all of steps S10, S15, and S16 are affirmative. There is no. That is, when the vehicle body speed VS of the vehicle is equal to or greater than the control start vehicle body speed threshold value KVS1, the wheels FR, FL are operated by depressing the brake pedal 37 by the driver of the vehicle, rather than executing the braking control during turning. The turning radius of the vehicle can be shortened by applying braking force to each of, RR and FL. Therefore, when the effect based on the execution of the braking control during turning is small, the execution of the braking control during turning can be avoided.

  (7) Similarly, when the brake pedal 37 is depressed, braking force is applied to the wheels FR, FL, RR, FL by applying braking force to the wheels FR, FL, RR, FL, respectively. The turning radius of the vehicle is shorter than when turning without being applied. Therefore, inadvertent execution of the braking control during turning when the brake pedal 37 is depressed can be avoided.

The embodiment may be changed to another embodiment as described below.
In the embodiment, the case where the vehicle turns rightward is described, but the case where the vehicle turns leftward may be embodied. In this case, the control wheel is the left rear wheel RL.

  -In embodiment, you may perform the fluctuation | variation of the braking force BP with respect to the rear wheel (for example, right rear wheel RR) inside a turning direction of a vehicle as shown below. That is, when the braking force BP for the rear wheel (for example, the right rear wheel RR) inside the turning direction of the vehicle is increased, the proportional solenoid valves 42, 44, 45, 50, 54 are closed and the solenoid valve 53 is closed. Is opened, and the pump 38 is driven. On the other hand, when the braking force BP for the rear wheel (for example, the right rear wheel RR) inside the turning direction of the vehicle is reduced, the solenoid valve 47 is closed and the drive of the pump 38 is stopped. By repeatedly executing such control, the braking force BP for the rear wheel (for example, the right rear wheel RR) inside the turning direction of the vehicle may be changed.

In the embodiment, the steering angle threshold KA may be a value smaller than the maximum steering angle.
-In embodiment, when performing braking control at the time of turning, you may make it give braking force BP to the front wheel inside the turning direction of a vehicle.

  In the embodiment, step S18 may not be executed. That is, when the turning braking control is executed, the magnitude of the braking force BP for the rear wheel (for example, the right rear wheel RR) inside the turning direction of the vehicle may be necessarily changed.

  -In embodiment, if the magnitude | size of the braking force BP with respect to the rear wheel (for example, right rear wheel RR) inside a turning direction of a vehicle fluctuates by predetermined amplitude KBP, it is not necessary to give periodicity to the fluctuation. .

  -In embodiment, it is not necessary to perform the determination process of step S13 of the braking control execution determination process routine at the time of turning. That is, the braking control during turning may be executed when all the determination processes in steps S10, S15, and S16 are affirmative regardless of the vehicle body speed VS.

  -Moreover, it is not necessary to perform the determination process of step S10 of the braking control execution determination process routine at the time of turning. That is, regardless of whether or not the driver depresses the brake pedal 37, the turning braking control may be executed when all the determination processes in steps S13, S15, and S16 are affirmative.

  Furthermore, the determination process in step S16 of the turning braking control execution determination process routine may not be executed. In other words, regardless of the operation mode of the operation switch SW2 (whether it is “ON” or “OFF”), when all the determination processes in steps S10, S13, and S15 are positive determinations, the braking control during turning is performed. You may make it perform.

  In the embodiment, the vehicle may not include the operation switch SW2. In this case, in step S16, the steering torque applied to the steering wheel 24 is detected by calculation based on the input signal from the steering torque sensor SE3, and when the steering torque is equal to or greater than a preset steering torque threshold, It is preferable to execute step S17. That is, unless the steering torque greater than or equal to the steering torque threshold is applied to the steering wheel 24 by steering of the driver's steering wheel 24 who intends to execute the braking control during turning, the determination processes in steps S10, S13, and S15 are performed. Even if all the determinations are affirmative, the braking control during turning is not executed. That is, when the vehicle driver does not intend to execute the turning braking control, the turning braking control can be prevented from malfunctioning.

  In the embodiment, the vehicle body speed VS is the largest wheel speed of the wheels FR, FL, RR, RL, the second largest wheel speed, and the third largest wheel. You may make it detect on the basis of any one among a speed and the average value of each wheel speed.

  -The vehicle body speed VS of the vehicle is not detected from the wheel speeds of the wheels FR, FL, RR, RL, but from the information acquired from the vehicle speed sensor or GPS (Global Positioning System). Also good.

  In the above embodiment, when executing the braking control during turning, the rear wheel (for example, the right rear wheel RR) inside the turning direction of the vehicle is set as a braking wheel, and the magnitude of the braking force BP with respect to the braking wheel is changed. However, the execution of the fluctuation control of the magnitude of the braking force BP for the braking wheel may be performed at a time other than the execution of the turning braking control. For example, when the vehicle body travels at a predetermined vehicle body speed toward the lower side of the slope, the variation control of the magnitude of the braking force BP with respect to the braking wheel may be performed. That is, when the vehicle travels at a predetermined vehicle speed toward the lower side of the slope, the braking force BP is applied to each wheel FR, FL, RR, FL of the vehicle, so each wheel FR, FL, RR, All FL are set to braking wheels. Then, the magnitude of the braking force BP for each braking wheel is varied. Therefore, when the vehicle body travels at a predetermined vehicle body speed toward the lower side of the slope, it is possible to satisfactorily suppress the generation of abnormal noise (resonance noise) from each wheel.

  In the embodiment, instead of the brake control device 11 mounted on the front wheel drive vehicle, the embodiment may be embodied in a brake control device mounted on the rear wheel drive vehicle, or may be applied to a brake control device mounted on the four wheel drive vehicle. It may be embodied.

  In the embodiment, the first hydraulic circuit 33 is connected to the wheel cylinder 36a for the right front wheel FR and the wheel cylinder 36b for the left front wheel FL, and the second hydraulic circuit 34 is for the right rear wheel RR. The wheel cylinder 36c and the wheel cylinder 36d for the left rear wheel RL may be connected to each other.

  In the embodiment, the braking force applying mechanism 15 converts the operation amount of the brake pedal 37 by the driver of the vehicle into an electric signal, and applies the braking force based on the electric signal to each wheel FR, FL, RR, RL. The so-called brake-by-wire method may be used.

The block diagram of the vehicle carrying the braking control apparatus in this embodiment. The block diagram of the braking force provision mechanism in this embodiment. The flowchart which shows the braking control execution determination processing routine at the time of turning in this embodiment. The timing chart which shows the fluctuation | variation of the braking force with respect to the rear wheel inside the turning direction of this vehicle in the vehicle carrying the braking control apparatus of this embodiment. (A) is a timing chart for explaining how abnormal noise is generated from the rear wheel side inside the turning direction of a vehicle equipped with a conventional braking control device, and (b) is equipped with the braking control device of this embodiment. 6 is a timing chart for explaining how the generation of abnormal noise from the rear wheel side on the inner side in the turning direction of the vehicle is suppressed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Braking control apparatus, 15 ... Braking force provision mechanism, 16 ... ECU (control means, vehicle body speed calculating means, steering angle calculating means), 24 ... Steering wheel, A ... Steering angle, BP ... Braking force, BP1 ... Normal control Power, FR, FL, RR, RL ... wheel, KA ... steering angle threshold, KBP ... predetermined cycle, KC ... predetermined cycle, KVS2 ... vehicle speed threshold for starting fluctuation, VS ... vehicle speed.

Claims (5)

A braking control device for a vehicle mounted on a vehicle having a braking force applying mechanism (15) that is driven when a braking force is applied to wheels (FR, FL, RR, RL) disposed on both the left and right sides of the traveling direction of the vehicle. (11)
Control means (16) for controlling the braking force applying mechanism (15) when applying a braking force (BP) to at least one of the wheels (FR, FL, RR, RL) is provided. ,
The control means (16) is configured to apply the braking force when a braking force (BP) is applied to at least one of the wheels (FR, FL, RR, RL) during travel of the vehicle. The wheel (RR) to which (BP) is applied is set as a braking wheel, and the magnitude of the braking force (BP) applied to the braking wheel (RR) is varied with a predetermined amplitude (KBP) set in advance. A braking control device for a vehicle for controlling the braking force applying mechanism (15). The control means (16) sets the magnitude of the braking force (BP) to the braking wheel (RR) during traveling of the vehicle so that the fluctuation period becomes a predetermined period (KC) set in advance. The vehicle braking control device according to claim 1, wherein the braking force applying mechanism (15) is controlled. A vehicle body speed calculating means (S12) for calculating the vehicle body speed (VS) of the vehicle;
When the vehicle speed (VS) calculated by the vehicle speed calculation means (S12) is less than a preset vehicle speed threshold (KVS2) when the vehicle is running, the control means (16) The braking of the vehicle according to claim 1 or 2, wherein the braking force applying mechanism (15) is controlled so as to vary the magnitude of the braking force (BP) with respect to the braking wheel (RR) with the predetermined amplitude (KBP). Control device. Steering angle calculation means (S14) for calculating the steering angle (A) of the steering (24) of the vehicle,
The control means (16) determines the turning direction of the vehicle when the absolute value of the steering angle (A) calculated by the steering angle calculation means (S14) is not less than a preset steering angle threshold value (KA). An inner wheel (RR) is set as the braking wheel, and the braking force applying mechanism (15) is used to vary the magnitude of the braking force (BP) with respect to the braking wheel (RR) with the predetermined amplitude (KBP). The vehicle braking control device according to any one of claims 1 to 3, which controls the vehicle. A vehicle braking control method for controlling braking force applied to wheels (FR, FL, RR, RL) disposed on both right and left sides of a traveling direction of a vehicle,
When a braking force (BP) is applied to at least one of the wheels (FR, FL, RR, RL) during traveling of the vehicle, the braking force (BP) is applied. A vehicle braking control method in which a wheel (RR) is set as a braking wheel, and a magnitude of a braking force (BP) with respect to the braking wheel (RR) is changed with a predetermined amplitude (KBP) set in advance.

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