JP5720066B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device, and more particularly to a technique for improving a change in braking performance caused by a clearance between a brake drum and a brake shoe in a vehicle including a drum-type brake device.

  As a technique for improving the change in the braking performance as described above, Patent Document 1 discloses that a brake is applied to a brake drum (in the literature, a friction target member) by applying a brake pressure when the driver does not perform a brake operation in a stopped state. A control mode in which a shoe (a friction member in the literature) is controlled to be pressed, pressure is gradually increased during the pressing control, and a pressure instruction signal is stored when the vehicle deceleration reaches a predetermined threshold. Is described. In this patent document 1, precharging is performed to close the gap between the brake drum and the brake shoe based on the pressure instruction signal stored when there is no driver's brake operation thereafter, and braking force is applied in the driver's braking operation. The point which prevents the delay of effect of is described.

JP 2009-184379 A

  As described in Patent Document 1, in the case where control is performed such that the brake pressure is applied and the brake drum and the brake shoe are brought into contact with each other when the vehicle is stopped, the operation noise is generated, so that the driver only feels uncomfortable or uncomfortable. Rather, since the frequency of operation of the pressure source and the control valve that generate the brake pressure increases, there is room for improvement in terms of causing a decrease in durability.

  For example, in a vehicle equipped with drum brakes on the left and right wheels, if the difference in clearance between the brake drums on the left and right wheels and the brake shoe is different, the braking force applied to the left and right wheels when the brake operation is performed to stop the vehicle Since there is a difference in the timing at which the motor acts and the magnitude of the braking force, the yaw moment acts on the vehicle.

  In addition, when the brake operation is performed in a case where the clearance difference between the left and right brake drums and the brake shoes is different, the stability of the vehicle may be impaired due to the yaw moment acting on the vehicle, and there is room for improvement.

  As a countermeasure against such an inconvenience, although the control for performing the precharge described in Patent Document 1 is considered to be effective, the control for operating the brake is required to obtain the pressure instruction signal as described above. This makes the driver uncomfortable and uncomfortable, and makes it difficult to employ in terms of causing a decrease in durability.

  An object of the present invention is to rationally configure a brake control device that can maintain the stability of a vehicle when a brake is operated even if the brake drums and brake shoes of the left and right wheel brake devices have different clearances. .

A feature of the present invention is that a straight travel detection means for detecting a straight travel of the vehicle and a brake drum and a brake shoe included in a brake device for the left and right wheels based on a brake operation by the driver when the straight travel of the vehicle is detected. a clearance laterality obtaining means for obtaining a value corresponding to the difference between the left and right of clearance to be formed, a storage means for storing a value corresponding to the left-right difference of the acquired clearance, corresponding to the left-right difference of the stored clearance And changing means for changing the start mode of the brake operation of the brake device for the left and right wheels based on the value. Further, the feature of the present invention is based on the straight travel detection means for detecting the straight travel of the vehicle, the stroke amount of the brake operation by the driver when the straight travel of the vehicle is detected, and the value corresponding to the deceleration of each of the left and right wheels. Determining whether or not a clearance formed between a brake drum and a brake shoe included in each brake device of the left and right wheels has occurred, and determining a clearance value of the left and right wheels determined to have generated a clearance. The clearance left / right difference acquisition means to be acquired, the storage means for storing the acquired clearance value, and the start of the brake operation of the brake device for the left and right wheels determined that the clearance has occurred based on the stored clearance value And changing means for changing the aspect.

According to this configuration, when the driver performs a brake operation at the time of the straight travel detection by the straight travel detection means, the clearance left / right difference acquisition means is configured such that the clearance between the brake drum and the brake shoe of the brake device of the left and right wheels, or Then, a value corresponding to the clearance left-right difference is acquired, and this value is stored in the storage means. In this way, when the brake operation is performed in a state where the clearance or the value corresponding to the clearance left-right difference is stored, the changing means performs the brake operation of the brake device for the left and right wheels based on the stored value. Change the starting mode.
That is, when the brake is operated in the straight traveling state, the clearance between the brake drum and the brake shoe of the left and right wheels or the value corresponding to the difference between the left and right clearances is acquired and stored. Need not be activated in advance. Also, by changing the start mode of the brake operation, for example, the braking force can be applied at the required timing even when the braking timings of the left and right wheel braking devices are matched or when only one of the left and right wheel braking devices is operated. It can also be obtained. In addition, the effect of the clearance can be reduced by advancing the braking timing.

  The present invention includes a yaw rate acquisition means for acquiring a yaw rate of a vehicle, wherein the clearance left-right difference acquisition means is based on an acquisition result of the yaw rate acquisition means during a brake operation by a driver when the straight traveling is detected. A value corresponding to the difference may be acquired.

  When there is a clearance difference between the left and right wheel brake devices, a yaw moment acts on the vehicle when the vehicle is stopped by a brake operation in a straight traveling state. For this reason, the clearance left-right difference acquisition means acquires the yaw rate of the vehicle by the yaw rate acquisition means during the braking operation in the straight traveling state, and from this acquisition result, a value corresponding to the left-right difference of the clearance in the brake device for the left and right wheels is obtained. You can get it. This yaw rate may be acquired from a yaw rate sensor, or an estimated yaw rate based on an output value of a lateral acceleration sensor, a wheel speed sensor, or a steering angle sensor may be acquired, and the acquisition method is not particularly limited.

The present invention includes wheel cylinder pressure acquisition means for acquiring an internal pressure of a wheel cylinder that operates a brake shoe included in the brake device for the left and right wheels, and the clearance right / left difference acquisition means is a brake applied by a driver when the straight traveling is detected. A value corresponding to the left-right difference of the clearance may be acquired based on the acquisition result of the wheel cylinder pressure acquisition means at the time of operation.

When there is a clearance difference between the left and right wheel brake devices, when the vehicle is stopped by a brake operation in a straight traveling state, a difference occurs in the internal pressures of the left and right wheel cylinders at the start of the brake operation. For this reason, the clearance left-right difference acquisition means can acquire a value corresponding to the clearance left-right difference in the brake device for the left and right wheels from the acquisition result of the wheel cylinder pressure acquisition means during a brake operation in a straight traveling state.

In the present invention, the changing means is configured to be able to change the operation start condition at the time of brake operation of the brake device, and is equivalent to a value corresponding to the left-right difference of the clearance stored in the storage means , or The operation start condition for brake operation may be changed based on the clearance value .

  According to this, the operation start conditions of the brake devices for the left and right wheels can be set separately, and the operation start conditions for brake operation can be changed based on the clearance or a value corresponding to the difference between the left and right clearances. Assuming threshold values that determine the operation start timings of the brake devices for the left and right wheels as the operation start conditions, the brake operation can be started at the timing when the information for starting the brake operation reaches the threshold among the brake devices for the left and right wheels. It becomes.

The present invention comprises a posture control means to stabilize the vehicle posture by automatic braking, the changing means, a value corresponding to the left-right difference of the clearance, or, based on the clearance value, the posture control The operation start condition of the brake operation in the means may be changed.

  According to this, for example, a lateral acceleration detected by a lateral acceleration sensor is assumed, a threshold is assumed as an operation start condition, and a braking mode of the attitude control means can be assumed so as to brake the brake device outside the turning during turning. . In such a control mode, a threshold lower than that of the other brake device is set for the left and right brake devices that can be judged to have a large clearance based on the clearance or a value corresponding to the difference between the left and right clearances as the operation start condition. To do. As a result, even when the brake device with the larger clearance is outside the turn, the brake operation related to the control is performed before the value of the detected lateral acceleration reaches the appropriate value (the initial value that requires the start of braking) when turning. Can be started, and braking delay can be suppressed.

The present invention includes brake assisting means for assisting the brake operation by automatic brake operation in addition to the driver's brake operation, and the changing means is a value corresponding to the left-right difference of the clearance or the clearance value On the basis of the above, the auxiliary amount of the brake operation in the brake auxiliary means may be changed.

  According to this, when performing the brake operation automatically, the automatic brake auxiliary means changes the auxiliary amount of the brake operation, and it becomes possible to suppress the braking delay.

  In the present invention, the changing means may change a brake operation start mode for at least one of the left and right wheel brake devices.

  According to this, a change means changes the start aspect of the brake operation of the brake device of one of a left-right wheel or both right-and-left wheels based on the memorize | stored value.

It is the schematic which shows the control system with which a vehicle is equipped. It is a block diagram which shows the structure of a control system. It is a figure which shows the outline of the control system containing a brake control unit. It is a flowchart which shows the outline | summary of control. It is a block diagram which shows the outline | summary of a process in a control system. It is a block diagram which shows the clearance left-right difference acquisition means of another embodiment (a). It is a block diagram which shows the clearance left-right difference acquisition means of another embodiment (b). It is a block diagram which shows the clearance left-right difference acquisition means of another embodiment (d).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕

  FIG. 1 shows a control system provided in a vehicle 10 such as a truck. The vehicle 10 is provided with left and right front wheels 11L and 11R and left and right rear wheels 12L and 12R. An engine E is provided at the front of the vehicle, and a speed change that transmits power from the engine E to the rear wheels 12 is transmitted. A device TM is provided. A steering wheel 13 is provided at a front position of a driver seat (not shown), and an accelerator pedal 14 for controlling the rotational speed of the engine E and front wheels 11 (left and right front wheels 11L, 11R) and the brake pedal 15 for artificially operating the brake device BK of the rear wheel 12 (generic name of the left and right rear wheels 12L and 12R), and the transmission TM is shifted near the driver seat. A shift lever 16 is provided.

  The steering wheel 13 transmits a rotational operation force to the front wheels 11 via the power steering unit 17 to perform driving steering (steering), and an operation system of the steering wheel 13 includes a steering sensor 13S that detects a steering amount. It has been. The vehicle 10 includes an accelerator pedal sensor 14S composed of a potentiometer so as to detect an artificial operation amount of the accelerator pedal 14, a brake pedal sensor 15S composed of a potentiometer so as to detect an artificial operation of the brake pedal 15, and an artificial A shift position sensor 16S for detecting the shift position of the shift lever 16 by operation is provided.

  A rotation sensor 24 for measuring the rotational speeds of the left and right front wheels 11 and the left and right rear wheels 12 is disposed in the vicinity of the brake device BK. Further, in the vicinity of the center of the vehicle 10, a yaw rate sensor 21 serving as a yaw rate acquisition unit that acquires a yaw moment value (yaw rate) acting on the vehicle 10, and a lateral acceleration sensor 22 that detects acceleration in the skid direction of the vehicle 10, And a control unit 25.

  The control unit 25 constitutes the brake control device of the present invention, and the control unit 25 performs a process of changing the start mode of the brake operation for at least one of the left and right wheel brake devices BK, for example. This process will be described later.

  As shown in FIG. 3, the brake device BK includes a pair of brake shoes BKS having an arc shape along the inner peripheral surface of the brake drum BKD with respect to the inside of the brake drum BKD. The drum brake type includes a wheel cylinder BKC that presses against the inner surface of the brake drum BKD. In this drum type brake, a braking force is obtained by bringing the pair of brake shoes BKS into contact with the inner surface of the brake drum BKD by the pressure of the brake fluid acting on the wheel cylinder BKK when the brake pedal 15 is depressed.

  The control unit 25 functions as an ECU having a microprocessor. Signals from sensors provided in each part of the vehicle 10 are input to the control unit 25, and the brake controller 26 and the throttle controller 28 are controlled. A signal is output. The brake controller 26 has a signal system that feeds back detection signals of the four rotation sensors 24, and an output control system that controls an electromagnetic valve and the like of the brake control unit 27.

  The brake controller 26 and the brake control unit 27 constitute the brake auxiliary means of the present invention. This brake auxiliary means assists the four brake devices BK by automatic operation in addition to the driver's brake operation. In order to realize such control, the brake control unit 27 supplies / discharges brake fluid supplied to the brake devices BK of the left and right front wheels 11 and brake devices BK of the left and right rear wheels and supplies brake fluid supplied to the brake devices BK. Control the pressure. This brake assisting means is conventionally called an ABS (Anti-lock Brake System), a TCS (Traction Control System), etc., and the stable running of the vehicle 10 is revealed by this control.

[Control configuration]
As shown in FIG. 2, the control unit 25 includes the steering sensor 13S (an example of a straight traveling detection unit), an accelerator pedal sensor 14S, a brake pedal sensor 15S, a shift position sensor 16S, and a yaw rate sensor 21 (an example of a yaw rate acquisition unit). In addition, detection signals from the lateral acceleration sensor 22 and the rotation sensor 24 are input, and control signals are output to the brake controller 26 and the throttle controller 28. The control unit 25 includes a turning stabilization control unit 31 (an example of a posture control unit), an emergency brake stabilization control unit 32 (an example of a posture control unit), a skid prevention control unit 33, a clearance left / right difference acquisition unit 34, and a storage. Means 35, threshold setting means 36 (an example of changing means), a brake control output unit 37, and an engine control output unit 38 are provided.

  The turning stabilization control unit 31 controls the brake device BK outside the turning based on a signal from the steering sensor 13S, a signal from the lateral acceleration sensor 22 and a clearance value CLE to be described later in order to stabilize the vehicle 10 during turning. Realizes turning stabilization control by brake operation.

  When an emergency brake operation is performed, the emergency brake stabilization control unit 32 operates the vehicle 10 by independently braking the left and right brake devices BK based on a signal from the brake pedal sensor 15S and a clearance value CLE described later. The emergency brake stabilization control is achieved to suppress the yaw moment acting on the vehicle 10 and stabilize the posture of the vehicle 10.

  The side slip prevention control unit 33 controls the rotation speed of the engine E based on signals from the yaw rate sensor 21, the side acceleration sensor 22, the steering sensor 13 and the like in order to suppress the side slip of the vehicle 10 when the side slip of the vehicle 10 occurs. Side slip prevention control is realized by one or both of the control of the brake device BK.

  The turning stabilization control unit 31, the emergency brake stabilization control unit 32, and the skid prevention control unit 33 are configured by software, but may be configured by hardware. You may comprise by a combination.

  The clearance left / right difference acquisition unit 34 acquires a signal from the yaw rate sensor 21 when the driver performs a brake operation in a state where the vehicle 10 is in a straight traveling state based on a signal from the steering sensor 13S. . When it is detected from the yaw rate acquired from the yaw rate sensor 21 that a yaw moment is acting on the vehicle 10 (when the behavior of the vehicle 10 is detected), the value of this yaw moment is set to the left and right brake devices BK. The clearance value CLE is acquired as a value corresponding to the left-right difference in clearance between the inner peripheral surface of the brake drum BKD and the brake shoe BKS (strictly, the lining provided in the brake shoe BKS).

  That is, the phenomenon in which the yaw moment acts on the vehicle 10 when a manual braking operation is performed while the vehicle 10 is traveling straight can be attributed to the difference in response between the left and right brake devices BK. In addition, the clearance left / right difference acquisition means 34 can be regarded as a relative response delay detection means. Therefore, the above-described turning stabilization control and emergency brake stabilization are performed by acquiring the yaw rate value by the clearance left-right difference acquisition unit 34 during the brake operation and performing control (control mode to be described later) using the acquired yaw rate value as the clearance value CLE. The vehicle 10 can be satisfactorily stabilized by reflecting the clearance value CLE in the brake operation in the control and suppressing the response delay of the brake device BK.

  Considering the brake performance (effectiveness) of the brake device BK, at the initial stage of braking operation, the brake device BK with high brake performance (good effect) of the left and right wheels exerts strong braking force at the initial stage of brake operation. Therefore, it is conceivable that the yaw moment is also generated due to the difference in the braking force. For this reason, setting the yaw rate value acquired by the clearance left / right difference acquisition means 34 as the clearance value CLE does not necessarily reflect the clearance difference between the inner peripheral surface of the brake drum BKD and the brake shoe BKS. In the present invention, the expression of the clearance value CLE is used as the name of the factor that causes the yaw moment.

  In the present embodiment, the stabilization control is realized based on a value (clearance value CLE) corresponding to the difference between the left and right clearances formed between the brake drum BKD and the brake shoe BKS of the brake device for the left and right wheels. However, instead of this, stabilization control is realized from the clearance value (the value that reflects the actual clearance value) formed between the brake drum and brake shoe of the brake device BK of the left and right wheels. The processing for detecting the clearance value is described in other embodiments (a), (b), and (d) described later.

  The storage means 35 performs a process of storing the clearance value CLE information in a nonvolatile memory such as an EEPROM provided in the control unit 25. Note that the storage means 35 may include a nonvolatile memory. The threshold value setting means 36 sets the threshold value as an operation start condition (start mode) of the brake operation for at least one of the left and right brake devices BK in the left and right brake devices BK in the aforementioned turning stabilization control and emergency brake stabilization control. Perform processing to set each separately.

  The brake control output unit 37 outputs a control signal to the brake control unit 27 when the intervention of the brake device BK is required, and the engine control output unit 38 outputs the control signal to the throttle controller 28 when the engine speed needs to be controlled. Output a control signal.

[Brake control unit]
As shown in FIG. 3, the brake control unit 27 transmits the stepping force of the brake pedal 15 to the master cylinder 42 by the booster 41, and controls the brake fluid supplied from the front fluid passage 42 </ b> F of the master cylinder 42 to the left and right. The brake fluid supplied from the rear fluid passage 42R of the master cylinder 42 to the wheel cylinder BKC of the brake device BK of the left and right rear wheels 12L, 12R is supplied to the wheel cylinder BKC of the brake device BK of the front wheels 11L, 11R. It has the composition to do.

  The brake control unit 27 includes a main fluid passage 43 through which brake fluid is sent from the front fluid passage 42F and a main fluid passage 43 through which brake fluid is sent from the rear fluid passage 42R. These two main fluids The hydraulic circuit formed on the downstream side of the passage 43 is configured equally.

  The brake fluid from the main fluid passage 43 is supplied to the proportional differential pressure valve 44, and is branched to the downstream side of the proportional differential pressure valve 44 to both the two branch fluid passages 45 leading to the wheel cylinder BKC. A normally closed outlet valve 48 is interposed in a drainage passage 47 that further branches from the inlet valve 46 on the wheel cylinder BKC side.

  The proportional differential pressure valve 44 is configured to be able to adjust the pressure of the brake fluid by energization. The inlet valve 46 is configured as an electromagnetically operated two-position switching valve that is in a communication state when not energized and is in a cutoff state when energized. The outlet 47 valve is configured as an electromagnetically operated two-position switching valve that is cut off when not energized and communicates when energized.

  A drain passage 47 from the two outlet valves 48 is provided with a reservoir 49 for temporarily storing brake fluid, and a return fluid passage 50 for returning the brake fluid from the reservoir 49 to the main fluid passage 43. Further, a pump P driven by an electric motor M so as to suck the brake fluid from a drainage passage 47 to which the brake fluid is joined and sent from the two outlet valves 48 and return it to the main fluid passage 43, and a supply fluid passage 51. It has.

  A feedback signal system is formed in which the detection signal of the rotation sensor 24 disposed in the vicinity of each brake device BK is input to the brake controller 26, and the proportional differential pressure valve 44, the branch liquid passage 45, the inlet valve 46, An output signal system for controlling the electric motor M is formed.

  During control, the brake controller 26 operates the inlet valve 46 in the shut-off state and operates the outlet valve 48 in the communication state to release the pressure of the brake fluid in the branch liquid passage 45 to the drainage passage 47, and the brake device BK. It becomes possible to reduce the braking force. On the contrary, the brake controller 26 operates the inlet valve 46 in the communication state and operates the outlet valve 48 in the shut-off state in a state where the pump P is operated, so that the brake fluid of the pump P is branched. The braking force can be increased by supplying the brake device BK from 45. In the ABS described above, the inlet valve 46, the outlet valve 48, etc. are operated in a state where the signal of the rotation sensor 24 is fed back to the brake controller 26 in order to suppress the phenomenon that the wheel is locked when the driver performs a braking operation. By doing so, control is performed to supply and discharge the brake fluid to and from the brake device BK in a short time.

  When one of the above-described turning stabilization control, emergency brake stabilization control, and skid prevention control is executed by using such a configuration, the brake controller 26 controls the brake control unit 27. Thus, the brake device BK is automatically operated.

[Control form]
As described above, since the brake device BK is configured as a drum brake type, there may be a difference in the clearance between the inner peripheral surface of the brake drum BKD and the brake shoe BKS in the left and right brake devices BK. When the turning stabilization control or the emergency brake stabilization control is executed in the situation where the clearance difference is generated as described above, the braking force is applied when the brake operation of the brake device BK having the larger clearance is started. As a result, the time lag until the time is increased and an appropriate braking force cannot be obtained. In order to prevent such inconvenience, when operating the brake device BK having a larger clearance, the braking force is applied at a necessary timing by setting the above-described threshold value so as to advance the start timing of the brake operation. The control to act is realized.

  The outline of the control flow is shown in the flowchart of FIG. 4, and the information flow at the time of this control is shown in the block diagram of FIG. In the control shown in the flowchart, the clearance value CLE is first acquired and stored (step # 01).

  In this control, when a yaw moment is applied to the vehicle 10 when the vehicle 10 is stopped by a brake operation by the driver in a state where it is detected that the vehicle 10 is traveling straight, the clearance left-right difference acquisition unit 34 performs the yaw rate. The detection signal Yr of the sensor 21 is acquired and set as a clearance value CLE.

  That is, when it is determined that the vehicle is traveling straight from the detection signal SSW of the steering sensor 13S and it is determined that the brake operation is performed by the operation signal SBP of the brake pedal sensor 15S, the rotation signal RS of the rotation sensor 24 is determined. Based on this, the traveling speed at the initial stage of the brake operation is obtained, and the detection signal Yr (yaw rate) of the yaw rate sensor 21 is obtained. And the clearance value CLE is calculated | required from the calculation of the peak value of the acquired detection signal Yr (yaw rate) and traveling speed, and the process passed to the memory | storage means 35 is performed.

  In this process, the peak value of the detection signal Yr (yaw rate) when an artificial braking operation is performed when the vehicle 10 travels straight at a predetermined speed is used as the clearance value CLE. Contains information indicating the direction of action of the yaw moment. In the above-described processing, the clearance value CLE is corrected from the calculation based on the peak value of the detection signal Yr and the traveling speed in order to eliminate the variation in the detection signal Yr (yaw rate) due to the traveling speed. Note that, instead of the process of correcting by calculation in this way, the processing mode may be set so that the clearance value CLE is corrected from the peak value and the traveling speed based on preset table data.

  In the block of the clearance left / right difference acquisition means 34 shown in FIG. 5, the change in the hydraulic pressure in the master cylinder 42 is shown as a graph Pm. From this graph Pm, the detection signal Yr of the yaw rate sensor 21 is generated at the beginning of the brake operation. I understand that. In the figure, a graph that protrudes upward and a graph that protrudes downward are shown as detection signals Yr when the yawing directions are different.

  The storage means 35 performs processing for storing a predetermined number of clearance values CLE, discards the oldest clearance value CLE every time the clearance value CLE is acquired (every brake operation), and sets the number including the latest clearance value CLE. The average value (arithmetic mean) of the clearance value CLE is calculated, and the average value of the clearance value CLE already stored in a nonvolatile memory such as an EEPROM is updated and stored. When calculating the average value in this way, if the acquired clearance value CLE is abnormal, it is also possible that the wheel slipped due to freezing of the road surface, etc. Processing that is not reflected in the value is performed.

[Another Embodiment of Processing in Detection Result Storage Unit]
In this process, a process of calculating an average value of the clearance value CLE is performed. Instead of this process, for example, the latest value among the clearance values CLE acquired during the brake operation is already stored. The processing mode may be set so that the clearance value CLE is updated and stored.

  In the drum type brake device BK, when the clearance between the inner peripheral surface of the brake drum BKD and the brake shoe BKS (lining) increases due to wear of the lining provided in the brake shoe BKS, the clearance is automatically reduced. The adjustment mechanism is provided. Since this adjustment mechanism performs a ratchet type operation, the clearance is allowed to expand to a predetermined value. Therefore, it is normal to produce a clearance difference between the left and right brake devices BK, and the control of the present invention is required.

  Next, the threshold setting means 36 sets the threshold TC of the left and right brake devices BK (# 02 step).

  The threshold value TC is an example of information for determining the operation start condition of the left and right brake devices BK, and is a superordinate concept of the left threshold value LTC and the right threshold value RTC. The threshold TC is a value that determines the operation start timing of the brake device BK based on the detection signal Gy (lateral acceleration) of the lateral acceleration sensor 22 in the turning stabilization control, and the operation signal SBP of the brake pedal sensor 15S in the emergency brake stabilization control. It is a value that determines the operation start timing of the brake device BK based on the above. In particular, in this control, the brake device BK for the left front wheel 11L and the brake device BK for the left rear wheel 12L are the left brake device BK, the brake device BK for the right front wheel 11R, and the right rear wheel. The brake device BK of the wheel 12R is the right brake device BK. Accordingly, an equal left threshold value LTC is set for the front and rear brake devices BK on the left side of the vehicle 10, and an equal right threshold value RTC is set for the right and rear brake devices BK.

  When the clearance value CLE stored in the storage means 35 indicates a counterclockwise yaw moment, the threshold setting means 36 determines the right threshold from the clearance value CLE as shown in the block of the threshold setting means 36 shown in FIG. RTC is required. In other words, when the counterclockwise yaw moment is shown during the brake operation, the clearance of the right brake device BK is large, and therefore the value of the right threshold value RTC is decreased in order to accelerate the operation of the right brake device BK. When the clearance is small (CLE1 or less), the right threshold value is set to the initial value GyTH.

  In the drawing, only the processing for obtaining the right threshold value RTC for the right brake device BK is described, but when the right threshold value RTC is set in this way, the initial value GyTH is used as the left threshold value LTC for the left brake device BK. Is set. That is, since the clearance value CLE is a relative value, when setting one threshold value, the initial value GyTH is set as the other threshold value.

  Next, when the steering wheel 13 is operated and the vehicle 10 starts to turn, the process proceeds to turning stabilization control (steps # 03 and # 04).

  In the turning stabilization control, the turning stabilization control unit 31 acquires the detection signal SSW from the steering sensor 13S and the detection signal Gy (lateral acceleration) of the lateral acceleration sensor 22, and outputs a control signal to the brake controller 26. The brake control unit 27 implements the brake operation on the outside of the left and right brake devices BK.

  Specifically, as shown in the block of the turning stabilization control unit 31 in FIG. 5, when the right turn is performed, the detection signal Gy of the lateral acceleration sensor 22 reaches the left threshold LTC (X3). Brake operation for stabilizing the turning performance of the left brake device BK is started. On the contrary, when the left turn is performed, the brake operation for stabilizing the turning performance of the right brake device BK is performed at the timing (X1) when the detection signal Gy of the lateral acceleration sensor 22 reaches the right threshold value RTC. Be started. The brake device BK on the side without the clearance (CLE1, CLE2 or less) starts the brake operation for turning stabilization control at the timing (X2, X4) when the detection signal Gy reaches the initial value GyTH.

  In this way, even when the vehicle 10 turns in either the left or right direction, the braking force is applied to the wheels on the outer side of the turn so that the vehicle 10 is stabilized. In this turning stabilization control, when the lateral acceleration during turning and right turning is small and does not reach the threshold values (GyTH, RTC, LTC), neither the left or right brake device BK is operated.

  Next, when the brake pedal 15 is operated in an emergency and so-called sudden braking is applied, the process shifts to emergency brake stabilization control (steps # 05 and # 06).

  In the emergency brake stabilization control, the emergency brake stabilization control unit 32 acquires an emergency brake state based on the operation signal SBP from the brake pedal sensor 15S, outputs a control signal to the brake controller 26, and the brake control unit 27 This is realized by operating the brake device BK. The acquisition of the emergency brake state is not particularly limited as long as a known technique is applied.

  Specifically, as shown in the block of the emergency brake stabilization control unit 32 in FIG. 5, the emergency brake operation is determined from the pedal speed calculated from the operation signal SBP of the brake pedal sensor 15S, and the brake operation of the emergency brake is performed. Is started. When there is a clearance in the right brake device BK, the right threshold value RTC is set to be smaller than the left threshold value TH (initial value), so the right brake device in the situation where the pedal speed of the brake pedal 15 is low (X6). The emergency brake operation of BK starts, and the auxiliary amount of brake operation is a large value. Further, when the pedal speed is further increased, the emergency brake operation of the left brake device BK is started at X9. As a result, when the brake pedal 15 is urgently operated, the brake device BK having the larger clearance is activated at an early stage to simultaneously apply the same braking force from the left and right brake devices BK to stabilize the vehicle 10. It is possible to stop the vehicle in a standing state.

  In particular, the emergency brake stabilization control is intended to stabilize the vehicle 10 at the initial stage of the brake operation. When the brake pedal 15 is continuously operated and a side slip occurs in the vehicle 10, a side slip prevention control unit is provided. 33 outputs a control signal from the brake control unit 27 and the throttle controller 28 based on detection signals from the yaw rate sensor 21, the lateral acceleration sensor 22, etc., thereby releasing the wheel lock and adjusting the traveling speed. By means of this, skidding is suppressed.

  This control continues until reset (step # 07). By continuing control in this way, the clearance value CLE is acquired every time the vehicle 10 stops, and the threshold value TC that reflects the latest clearance value CLE is set.

[Effect of the embodiment]
In this control, the brake device including the front wheel 11 and the rear wheel 12 is obtained by regarding the detection signal Yr (yaw rate) of the yaw rate sensor 21 during the brake operation in the straight traveling as the clearance value CLE of the left and right brake devices BK. In BK, it is possible to determine which side of the left and right side is large. Based on such determination, a threshold value TC for determining the intervention timing of the brake operation by the brake device BK is set, and the brake operation of the brake device BK is performed based on the threshold value TC. Even when the vehicle 10 turns in the direction, the vehicle 10 can be stabilized without causing a braking delay.

  Similarly, even when the vehicle is stopped by the emergency brake, the emergency brake stabilization control starts the control of the left and right brake devices BK separately based on the threshold value. As a result, the equal braking force is simultaneously applied from the left and right brake devices BK. To stabilize the posture of the vehicle 10.

  When the vehicle 10 travels straight ahead and stops due to manual operation of the brake pedal 15, the latest clearance value CLE is stored by updating the stored clearance value CLE each time the vehicle is stopped. Become. As a result, the left threshold value LTC and the right threshold value RTC take the most preferable values, and the vehicle 10 is well stabilized by any stabilization control.

[Another embodiment]
The present invention may be configured as follows in addition to the embodiment described above.

(A) As shown in FIG. 6, the clearance left-right difference acquisition means 34 is comprised. That is, a wheel cylinder sensor 55 (an example of a wheel cylinder pressure acquisition unit) that measures the internal pressure (Pcp) of the wheel cylinder BKC of the four brake devices BK is provided, and the detected value LCP of the left wheel cylinder sensor 55 and the right wheel A signal system for obtaining the detection value RCP of the cylinder sensor 55 is formed, and a signal system for obtaining the detection signal SSW of the steering sensor 13S and the operation signal SBP of the brake pedal sensor 15S is formed.

  When it is determined that the vehicle is traveling straight from the detection signal SSW of the steering sensor 13S and it is determined that the brake operation is performed by the operation signal SBP of the brake pedal sensor 15S, the left wheel cylinder sensor 55 The clearance value CLE is defined by setting a difference in timing (difference in detection signal rising timing) between the detection value LCP and the detection value RCP of the right wheel cylinder sensor 55 to a value corresponding to the clearance (a value reflecting an actual clearance value). Get as. Also in this control, the clearance value CLE is corrected by the traveling speed as described in the embodiment.

  That is, when a braking force is applied by the brake device BK, the internal pressure (Pcp) of the wheel cylinder BKC increases. When there is a difference in the clearance between the left and right brake devices BK, the right and left wheel cylinders BKC A time lag occurs in the increase of the internal pressure (Pcp). Since this time lag corresponds to the clearance value CLE, this is regarded as the clearance value CLE. In particular, in this other embodiment (a), the clearance value CLE between the brake device BK of the front wheel 11 and the brake device BK of the rear wheel 12 can be acquired independently, and the clearance values of the two types of brake devices BK are obtained. Accurate control is realized based on CLE.

(B) As shown in FIG. 7, the clearance left-right difference acquisition means 34 is comprised. That is, a signal system for obtaining detection values LSR and RSR of the rotation sensor 24 that detects rotations of the left and right front wheels 11L and 11R and the left and right rear wheels 12L and 12R is formed, and the detection signal SSW of the steering sensor 13S A signal system for obtaining the operation signal SBP of the brake pedal sensor 15S is formed.

  When it is determined that the vehicle is traveling straight from the detection signal SSW of the steering sensor 13S and it is determined that the brake operation is performed by the operation signal SBP of the brake pedal sensor 15S, the detection of the left rotation sensor 24 is performed. A difference in deceleration start timing between the value LSR and the detection value RSR of the right rotation sensor 24 is acquired as a clearance value CLE as a value corresponding to the clearance (a value reflecting an actual clearance value). Also in this other embodiment, as described in the embodiment, the clearance value CLE is corrected by the traveling speed.

  That is, when a braking force is applied by the brake device BK, the rotational speed (rpm) of the wheels is reduced. Therefore, when there is a difference in the clearance between the left and right brake devices BK, the rotational speeds of the left and right wheels ( rpm) causes a time lag at the start of deceleration. Since this time lag corresponds to the clearance value CLE, this is regarded as the clearance value CLE. Also in this other embodiment (b), the clearance value CLE between the brake device BK of the front wheel 11 and the brake device BK of the rear wheel 12 can be acquired independently, and the clearance value CLE of the two types of brake devices BK can be obtained. Based on this, accurate control is realized.

(C) One of the brake device BK of the left and right front wheels 11L and 11R of the vehicle 10 and the brake device BK of the left and right rear wheels 12L and 12R is a disc brake type, and the other is a drum brake type. Applies to Even in such a configuration, the clearance value CLE is obtained, and the threshold value is set based on the clearance value CLE, whereby the stabilization control of the vehicle 10 is realized.

(D) As shown in FIG. 8, the clearance left / right difference acquisition means 60 determines whether any brake device BK has a clearance. This determination is made based on the stroke amount Td of the brake operation by the driver obtained from the output signal of the brake pedal sensor 15S and the value Jd corresponding to the deceleration obtained from the output signal of the master cylinder pressure sensor. Of course, the value Jd corresponding to the deceleration may be obtained directly from the deceleration sensor.
At this time, if there is no clearance in any brake device BK, a value Jd corresponding to the deceleration is generated in response to the generation of the stroke amount Td. However, if any brake device BK has a clearance, a value Jd corresponding to deceleration is generated with a time lag from the generation of the stroke amount Td. The stroke amount Td when the value Jd corresponding to this deceleration occurs corresponds to the clearance value CLE in any brake device BK, and corresponds to the clearance value CLE based on the map stored in the threshold setting means 61. A turning control intervention threshold value TC is set and stored. In this case, when the clearance value CLE is smaller than the predetermined value CLE3, the control intervention threshold value of the turning stabilization control is set and stored as the initial value GyTH. When the clearance value CLE is larger than the value CLE3, the control intervention threshold value Gyf is set based on the map. Set and remember.
Then, the turning stabilization control unit 62 executes turning stabilization control when the lateral acceleration Gy acquired from the lateral acceleration sensor 22 is equal to or greater than the control intervention threshold GyTH or Gyf.

  INDUSTRIAL APPLICABILITY The present invention can be applied to any vehicle equipped with a disc brake type brake device and equipped with a control system that operates the left and right brake devices separately.

10 Vehicle 11 Wheel (front wheel)
12 wheels (rear wheels)
13S Straight running detection means (steering sensor)
21 Yaw rate acquisition means (yaw rate sensor)
31 Attitude control means (turning stabilization controller)
32 Attitude control means / brake auxiliary means (emergency brake stabilization controller)
34 Clearance left / right difference acquisition means 36 Change means (threshold setting means)
35 storage means 55 wheel cylinder pressure acquisition means (foil cylinder sensor)
BK Brake device BKC Wheel cylinder BKD Brake drum BKS Brake shoe CLE value (clearance value)

Claims (7)

Straight travel detection means for detecting straight travel of the vehicle;
Clearance left / right difference acquisition means for acquiring a value corresponding to the left / right difference of the clearance formed between the brake drum and the brake shoe of the brake device of the left and right wheels based on the brake operation by the driver when detecting the straight traveling of the vehicle When,
Storage means for storing a value corresponding to the left-right difference of the acquired clearance;
Brake control apparatus characterized by comprising a changing means for changing the start mode of the brake operation of the brake device of the left and right wheels based on a value corresponding to the left-right difference of the stored clearance. A yaw rate acquisition means for acquiring the yaw rate of the vehicle;
2. The clearance left-right difference acquisition unit acquires a value corresponding to the left-right difference of the clearance based on an acquisition result of a yaw rate acquisition unit during a brake operation by a driver when the straight traveling is detected. The brake control device described in 1. Straight travel detection means for detecting straight travel of the vehicle;
Formed between the brake drum and the brake shoe of the brake device of each of the left and right wheels based on the stroke amount of the brake operation by the driver when detecting the straight traveling of the vehicle and the value corresponding to the deceleration of each of the left and right wheels Clearance left / right difference acquisition means for determining whether or not clearance is generated, and acquiring clearance values of the left and right wheels determined to have clearance;
Storage means for storing the acquired clearance value;
A brake control device comprising: changing means for changing a start mode of a brake operation of the brake device for the left and right wheels determined that the clearance is generated based on the stored clearance value. The changing means is configured to be able to change the operation start conditions at the time of brake operation of the brake device,
Value corresponding to the left-right difference of the clearance, which is stored in the storage means, or based on the clearance value, both of claims 1 to 3, characterized in that changing the operation start condition of the brake actuation A brake control device according to claim 1. Equipped with posture control means for stabilizing the vehicle posture by automatic braking operation,
The said change means changes the operation start conditions of the brake operation in the said attitude | position control means based on the value equivalent to the right-and-left difference of the said clearance, or the said clearance value. The brake control device according to any one of the above. In addition to the driver's brake operation, equipped with a brake auxiliary means for assisting the brake operation by automatic brake operation,
The change means a value corresponding to the left-right difference of the clearance, or, based on the clearance value of claims 1 to 5, characterized in that to change the auxiliary amount of braking in the brake assist means The brake control apparatus as described in any one.   The brake control device according to any one of claims 1 to 6, wherein the changing unit changes a brake operation start mode for at least one of the brake devices for the left and right wheels.

Images