JP2009006832A - Anti-lock brake controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-lock brake controller for a vehicle reducing the braking distance by rapidly determining, by a simple computation content, that the friction coefficient of a traveling road surface is abruptly changed from a low value to a high value. <P>SOLUTION: A friction coefficient abrupt change determination means 61 determines that the friction coefficient is abruptly changed from a low value to a high value when: a slowly increasing mode is selected by all wheels based on the low friction coefficient; the elapsed time of the slowly increasing mode of at least one wheel is equal to or longer than the predetermined time; the deceleration of a vehicle exceeds the threshold for determination to the deceleration side; and the difference between the maximum value and the minimum value of the wheel corresponding vehicle body speed respectively estimated by wheel corresponding vehicle body speed estimation means 55A-55D is below the reference value. Control mode setting means 62A-62D change the control mode from the slowly increasing mode to the rapidly increasing mode when the slowly increasing mode is selected because the friction coefficient abrupt change determination means 61 determines that the friction coefficient of the traveling road surface is abruptly changed from a low value to a high value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes an actuator capable of individually adjusting a braking force exerted by a wheel brake mounted on each of a plurality of wheels; a wheel speed detecting unit that individually detects a wheel speed of each wheel; and a vehicle body speed. Vehicle body speed detection means; deceleration detection means for detecting vehicle deceleration; friction coefficient determination means for determining the level of the friction coefficient of the road surface based on the deceleration detected by the deceleration detection means; A lock tendency determining means for determining a lock tendency for each wheel based on the wheel speed detected by the wheel speed detecting means and the vehicle body speed detected by the vehicle body speed detecting means; Accordingly, a control mode for increasing or decreasing the braking force is determined for each wheel brake, and when the control mode is the increase mode, the friction coefficient determination Control mode setting means for switching between a sudden increase mode when it is determined that the coefficient of friction is high and a slow increase mode when it is determined that the coefficient of friction is low according to the determination result; and set by the control mode setting means And an actuator control means for controlling the operation of the actuator according to a control mode.

An antilock brake control device for a vehicle that can switch between a sudden increase mode and a slow increase mode in a control mode for increasing the braking force of a wheel brake during the antilock brake control is already known, for example, in Patent Document 1 .
JP 2004-196235 A

  By the way, in such an anti-lock brake control device, the slow increase mode is selected when the friction coefficient of the traveling road surface is low, and the rapid increase mode is selected when the friction coefficient is high, but the friction coefficient of the traveling road surface is increased from a low friction coefficient to a high friction coefficient. When the friction coefficient changes abruptly, the braking distance becomes long unless it quickly changes to the sudden increase mode. In detecting such a sudden change in the friction coefficient, it is possible to judge that the vehicle has changed from a low friction coefficient to a high friction coefficient when the deceleration of the vehicle suddenly changes to the negative side. In order to prevent misjudgment, it is necessary to set the amount of change in the vehicle deceleration, which is the criterion, to be relatively large, so that the change from the low coefficient of friction to the high coefficient of friction can be avoided. Detection tends to be delayed, causing a problem in responsiveness.

  The present invention has been made in view of such circumstances, and it is possible to quickly determine with a simple calculation content that the friction coefficient of the traveling road surface has suddenly changed from a low friction coefficient to a high friction coefficient, and an excellent response. An object of the present invention is to provide an anti-lock brake control device for a vehicle in which the performance is obtained.

  In order to achieve the above object, the present invention provides an actuator capable of individually adjusting a braking force exerted by a wheel brake mounted on each of a plurality of wheels; and wheel speed detection for individually detecting the wheel speed of each wheel. A vehicle speed detecting means for detecting the vehicle speed; a deceleration detecting means for detecting the deceleration of the vehicle; and determining the level of the friction coefficient of the traveling road surface based on the deceleration detected by the deceleration detecting means. A friction coefficient determining means for determining the locking tendency for each wheel based on the wheel speed detected by the wheel speed detecting means and the vehicle body speed detected by the vehicle body speed detecting means; A control mode for increasing or decreasing the braking force is determined for each wheel brake according to the determination result by the lock tendency determination means, and the control mode is an increase mode. Control mode setting means for switching between a rapid increase mode when it is determined to be a high friction coefficient and a slow increase mode when it is determined to be a low friction coefficient according to the determination result of the friction coefficient determination means; And an actuator control means for controlling the operation of the actuator according to a control mode set by the control mode setting means. In the anti-lock brake control device for a vehicle, each of the above-mentioned values based on the wheel speed detected by the wheel speed detection means. A wheel-corresponding vehicle speed estimating means for estimating a wheel-corresponding vehicle speed for each wheel; in a state where the slow increase mode is selected for all the wheels based on the fact that the friction coefficient determining means determines that the coefficient of friction is low. The deceleration of the vehicle is detected by the deceleration detection means when the elapsed time of the slow increase mode of at least one wheel is equal to or longer than a predetermined time. The friction coefficient is low when the threshold value for judgment exceeds the deceleration side, and the difference between the maximum and minimum wheel speeds estimated by the wheel speed estimation means is less than the reference value. A friction coefficient sudden change judging means for judging that the coefficient has suddenly changed from a coefficient to a high friction coefficient; and the control mode setting means has said that the friction coefficient of the road surface has suddenly changed from a low friction coefficient to a high friction coefficient. The control mode for all the wheels is switched from the slowly increasing mode to the rapidly increasing mode in accordance with the determination by the friction coefficient rapid change determining means.

  According to the above configuration of the present invention, it is determined that the pressure increase is insufficient because the elapsed time of the slow increase mode of at least one wheel is equal to or longer than the predetermined time, and the maximum value and the minimum value of the vehicle speed corresponding to the wheel are When the difference is less than the reference value, it is determined that the wheel speeds of the plurality of wheels are changing almost synchronously, and in such a state, the vehicle's deceleration exceeds the threshold value for judgment and travels Since it is judged that the friction coefficient of the road surface has suddenly changed from a low friction coefficient to a high friction coefficient, it is possible to set a threshold value for judgment strictly, and the friction coefficient of the running road surface suddenly changes from a low friction coefficient to a high friction coefficient. Thus, it is possible to quickly determine that the change has been made with simple calculation contents, thereby ensuring excellent responsiveness and shortening the braking distance.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 6 show an embodiment of the present invention, FIG. 1 is a diagram showing a drive system and a brake system of a front-wheel drive vehicle, and FIG. 2 is a hydraulic system diagram showing a configuration of a brake hydraulic pressure control device. FIG. 3 is a longitudinal sectional view of a normally open type electromagnetic valve, FIG. 4 is a diagram showing a change in attraction force with respect to a change in stroke of the valve shaft, FIG. 5 is a block diagram showing the configuration of a controller, and FIG. It is a figure which shows the relationship of speed.

  First, in FIG. 1, power is transmitted from the power unit P to the left front wheel WA and the right front wheel WC which are driving wheels. The power unit P shifts the output of the engine E and the engine E to the left front wheel. It is comprised with the transmission T for transmitting to WA and the right front wheel WC. The left front wheel WA and the right front wheel WC are equipped with a left front wheel wheel brake BA and a right front wheel brake BC, which are drive wheel brakes. The driven wheel, the right rear wheel WB and the left rear wheel WD, A right rear wheel brake BB and a left rear wheel brake BD are mounted.

  Each of the wheel brakes BA to BD is a disc brake that operates by the action of hydraulic pressure, and the hydraulic pressure from the actuator 1 acts on each of the wheel brakes BA to BD. The actuator 1 can adjust the output hydraulic pressure of the tandem master cylinder M that outputs the hydraulic pressure by the brake operation of the brake pedal 2 to be applied to the wheel brakes BA to BD.

  The operation of the actuator 1 is controlled by a controller C. The controller C includes wheel speed detecting means 6A, 6C for driving wheels for detecting the driving wheel speeds of the left front wheel WA and the right front wheel WC as driving wheels. Detection value, detection values of driven wheel speed detection means 6B and 6D for detecting the driven wheel speeds of the right rear wheel WB and the left rear wheel WD, which are driven wheels, and the brake fluid pressure of each wheel brake BA to BD. Detection values of the brake pressure detection means 7A to 7D to be input are input.

  In FIG. 2, the actuator 1 corresponds to the first hydraulic passage 10A corresponding to the left front wheel brake BA and the right rear wheel brake BB, and to the right front wheel brake BC and the left rear wheel brake BD. The first hydraulic pressure passage 10B, the first and second reservoirs 11A and 11B different from the reservoir R provided in the master cylinder M, and the first and second reservoirs 11A are driven by a common single electric motor 13. , 11B can pump up the brake fluid and discharge it to the first and second hydraulic pressure passages 10A, 10B, and the first output port 3A and the first hydraulic pressure passage 10A of the master cylinder M. A normally open solenoid valve 15A interposed therebetween, a normally open solenoid valve 15B interposed between the second output port 3B of the master cylinder M and the second hydraulic pressure passage 10B, and a first Between the suction side of the pump 14A and the first output port 3A of the master cylinder M, and between the suction side of the second pump 14B and the second output port 3B of the master cylinder M. The normally closed solenoid valve 16B, the left front wheel brake pressure adjusting means 17A provided between the first hydraulic pressure path 10A and the left front wheel wheel brake BA, the first hydraulic pressure path 10A and the right rear wheel wheel brake BB. The right rear wheel brake pressure adjusting means 17B provided between the second hydraulic pressure path 10B and the right front wheel brake pressure adjusting means 17C provided between the right front wheel wheel brake BC, the second hydraulic pressure path 10B and the left rear wheel. Left rear wheel brake pressure adjusting means 17D provided between the vehicle wheel brakes BD.

  The left front wheel brake pressure adjusting means 17A is a normally open solenoid valve 18A provided between the first hydraulic pressure passage 10A and the left front wheel wheel brake BA, and a normal opening type solenoid valve 18A provided between the first reservoir 11A and the left front wheel wheel brake BA. A closed solenoid valve 19A and a check valve 20A connected in parallel to the normally open solenoid valve 18A to allow the brake fluid to flow from the left front wheel brake BA side to the first hydraulic pressure passage 10A side. Is done.

  According to such a left front wheel brake pressure adjusting means 17A, when the brake pedal 3 is depressed, the normally open solenoid valve 18A is opened when the normally closed solenoid valve 19A is closed. The brake force of the front left wheel brake BA can be increased by applying the hydraulic pressure of the output port 3A to the front left wheel brake BA, and both the normally open solenoid valve 18A and the normally closed solenoid valve 19A are provided. When closed, the brake fluid pressure of the left front wheel brake BA can be maintained to maintain the braking force of the left front wheel brake BA, and the normally open solenoid valve 18A is closed and the normally closed solenoid valve 19A is closed. By opening the valve, the brake fluid pressure of the left front wheel brake BA can be reduced to reduce the brake force of the left front wheel brake BA.

  The right rear wheel brake pressure adjusting means 17B includes a normally-open electromagnetic valve 18B provided between the first hydraulic pressure path 10A and the right rear wheel wheel brake BB, and between the first reservoir 11A and the right rear wheel wheel brake BB. A normally closed solenoid valve 19B provided and a check valve connected in parallel to the normally open solenoid valve 18B while allowing the brake fluid to flow from the right rear wheel brake BB side to the first hydraulic pressure passage 10A side. 20B, and by controlling the opening and closing of the normally open solenoid valve 18B and the normally closed solenoid valve 19B, the right rear wheel wheel brake BB is controlled in the same manner as the left front wheel brake pressure adjusting means 17A. The brake force can be controlled to increase, hold and decrease.

  The right front wheel brake pressure adjusting means 17C is a normally-open solenoid valve 18C provided between the second hydraulic pressure passage 10B and the right front wheel wheel brake BC, and a normal opening solenoid valve 18C provided between the second reservoir 11B and the right front wheel wheel brake BC. A closed solenoid valve 19C and a check valve 20C connected in parallel to the normally open solenoid valve 18C while allowing the brake fluid to flow from the right front wheel brake BC side to the second hydraulic pressure passage 10B side. In the same manner as the left front wheel brake pressure adjusting means 17A and the right rear wheel brake pressure adjusting means 17B, the right front wheel is controlled by controlling the opening and closing of the normally open type electromagnetic valve 18C and the normally closed type electromagnetic valve 19C. It is possible to switch and control the increase, retention and decrease of the brake force of the industrial wheel brake BC.

  The left rear wheel brake pressure adjusting means 17D is provided between a normally open solenoid valve 18D provided between the second hydraulic pressure path 10B and the left rear wheel wheel brake BD, and between the second reservoir 11B and the left rear wheel wheel brake BD. A normally closed solenoid valve 19D provided and a check valve connected in parallel to the normally open solenoid valve 18D while allowing the brake fluid to flow from the left rear wheel brake BD side to the second hydraulic pressure passage 10B side. 20D, and by controlling the opening and closing of the normally open solenoid valve 18D and the normally closed solenoid valve 19D, the left front wheel brake pressure regulating means 17A, the right rear wheel brake pressure regulating means 17B and the right As with the front wheel brake pressure adjusting means 17C, the braking force of the left rear wheel wheel brake BD can be controlled to be increased, held and decreased.

  Further, the first output port 3A of the master cylinder M and the first hydraulic pressure passage 10A are shut off by closing the normally open solenoid valve 15A, and the normally closed solenoid valve 16A is opened to open the first output of the master cylinder M. The first pump 14A is operated in a state where the port 3A is in communication with the suction side of the first pump 14A, and the normally open solenoid valves 18A, 18B in the left front wheel brake pressure adjusting means 17A and the right rear wheel brake pressure adjusting means 17B By controlling the opening and closing of the normally closed solenoid valves 19A and 19B, it is possible to control the increase, retention and decrease of the braking force of the left front wheel brake BA and the right rear wheel brake BB during non-braking operation. is there.

  Further, the second output port 3B of the master cylinder M and the second hydraulic pressure passage 10B are shut off by closing the normally open solenoid valve 15B, and the normally closed solenoid valve 16B is opened to open the second output of the master cylinder M. The second pump 14B is operated with the port 3B communicating with the suction side of the second pump 14B, and the normally open solenoid valves 18C, 18D in the right front wheel brake pressure adjusting means 17C and the left rear wheel brake pressure adjusting means 17D By controlling the opening and closing of the normally closed solenoid valves 19C and 19D, it is possible to control the increase, retention, and decrease of the braking force of the right front wheel brake BC and the left rear wheel brake BD during non-brake operation. is there.

  By the way, the braking force of the wheel brakes of the wheels WA to WD that are about to fall into the locked state during the braking operation in which the hydraulic pressure is applied to the wheel brakes BA to BD has the above increase, decrease, and holding modes. The anti-lock brake control is performed so that the normally closed electromagnetic valves 16A to 16D of the wheel brake pressure adjusting means 17A to 17D are turned on / off during the anti-lock brake control. On the other hand, the normally open solenoid valves 15A to 15D are on / off controlled and duty controlled in the middle between on and off, and each wheel brake BA according to the applied current of such an intermediate value. FIG. 3 shows the configuration of the normally open solenoid valve 15A among the normally open solenoid valves 15A to 15D configured to linearly change the fluid pressure on the BD side. It will now be described with ether.

  In FIG. 3, the normally open electromagnetic valve 15 </ b> A includes a solenoid portion 24 that exhibits electromagnetic force, and a valve portion 25 that is driven by the solenoid portion 24, and one surface 26 a of a fixed support block 26. The valve portion 25 is accommodated in a mounting hole 27 provided in the support block 26 so that the solenoid block 24 protrudes from one surface 26 a of the support block 26.

  The valve portion 25 includes a valve housing 28 that is formed of a magnetic metal into a stepped cylindrical shape. The valve housing 28 is fitted into the mounting hole 27 of the support block 26. A retaining ring 29 that engages with the valve housing 28 and prevents the valve housing 28 from being detached from the mounting hole 27 is fitted to the inner surface near the opening end of the mounting hole 27. In addition, annular seal members 30 and 31 are mounted at two positions spaced apart in the axial direction on the outer surface of the valve housing 28, and between the seal members 30 and 31, there is a gap between the support block 26 and the valve housing 28. An annular chamber 32 is formed.

  A cylindrical valve seat member 33 is press-fitted and fixed to the valve housing 28. In addition, a valve shaft 34 made of a nonmagnetic material is slidably fitted in the valve housing 28, and an output chamber 35 is formed between one end of the valve shaft 34 and the valve seat member 33, and faces the output chamber 35. A spherical valve element 36 that can be seated on a valve seat 33 a formed on the valve seat member 33 is fixed to one end of the valve shaft 34. Moreover, a return spring 37 is provided between one end of the valve shaft 34 and the valve seat member 33 to urge the valve shaft 34, that is, the valve body 36 in a direction away from the valve seat member 33.

  A filter 39 is attached to the valve housing 28 so as to be interposed between the hydraulic pressure path 38 provided in the support block 36 and the valve seat member 33 so as to be connected to the first hydraulic pressure path 10A. A filter 40 is mounted on the outer periphery of the valve housing 28 at a portion facing the annular chamber 32, and a passage 41 for allowing the output chamber 35 to communicate with the annular chamber 32 through the filter 40 is provided in the valve housing 28. . The annular chamber 32 communicates with the left front wheel wheel brake BA, and the support block 36 is provided with a hydraulic path 42 for communicating the annular chamber 32 with the left front wheel wheel brake BA. Further, the valve housing 28 is opened between the valve seat member 33 and the filter 39 when the pressure in the hydraulic pressure path 38 is lower than that in the annular chamber 32, and the brake fluid in the annular chamber 32 is returned to the hydraulic pressure path 38 side. A check valve 20A is provided.

  The solenoid part 34 guides the approaching / separating movement of the armature 46 with respect to the fixed core 45, the armature 46 that is coaxially connected to the other end of the valve shaft 34 in the valve part 35 and faces the fixed core 45. Guide cylinder 47, a bobbin 48 surrounding the guide cylinder 47, a coil 49 wound around the bobbin 48, a magnetic path frame 50 surrounding the coil 49, and the magnetic path frame 50 and the bobbin 48. The coiled spring 51 is provided.

  The fixed core 45 is formed in a cylindrical shape, and is coaxially and integrally connected to the center of one end of the valve housing 28. The guide tube 47 is formed in a thin bottomed cylindrical shape with a hemispherical closed end at one end made of a non-magnetic material such as stainless steel, and the tip of the fixed core 45 is connected to the other end of the guide tube 47. And the other end of the guide tube 47 is fixed to the fixed core 45 by welding, for example. In addition, the guide cylinder 47 protrudes from the one surface 36 a of the support block 36 in a mounted state in the mounting hole 37 of the valve housing 28.

  The bobbin 48 has a central hole 48 a through which the guide tube 47 is inserted and is formed of synthetic resin. A coil 49 is wound around the bobbin 48.

  The magnetic path frame 50 includes a magnetic path cylinder 52 that surrounds the bobbin 48 and the coil 49. At one end of the magnetic path cylinder 52, the closed end portion of the guide cylinder 47 protrudes from the center portion to the bobbin 48. The ring plate-like magnetic path plate 53 that abuts is caulked and engaged.

  On the other hand, the other end of the magnetic path cylinder 52 is integrally provided with a ring plate-like contact plate portion 52a that contacts the one end of the valve housing 28 around the fixed core 45, and this contact plate portion 52a. The base portion of the fixed core 45 is fitted to the inner periphery of the core. In addition, the other end of the coiled spring 51 whose one end is in contact with the contact plate portion 52 a is in contact with the bobbin 48.

  An armature 46 that can move toward and away from the fixed core 45 is housed in the guide tube 47, and one end of the valve shaft 34 that passes through the fixed core 45 movably is coaxial with the armature 46. Abutted. By the way, the valve shaft 34 is urged in a direction away from the valve seat member 33 by the spring force of the return spring 37, and the other end of the valve shaft 34 is always in contact with the armature 46. In response to the axial movement of the armature 46, the valve shaft 34, that is, the valve body 36 also moves in the axial direction.

  That is, in a state where the magnetic attractive force toward the fixed core 45 is not acting on the armature 46, the armature 46 is in a retracted position by the spring force of the return spring 37 until it is received at one end closed portion of the guide cylinder 47. At this time, the valve body 36 is separated from the valve seat member 33, and the normally open solenoid valve 15A is in the valve open state. When the armature 46 is magnetically attracted toward the fixed core 45 until the valve element 36 is seated on the valve seat member 33, the normally open solenoid valve 15A is closed.

  By the way, the resultant force of the hydraulic pressure of the output chamber 35 and the spring force of the return spring 37 acts on one end of the valve shaft 34, while the armature 46 is fixed to the other end of the valve shaft 34. The magnetic attraction force attracted to the core 45 side acts, and the valve shaft 34 is stroke-operated so that the resultant force of the fluid pressure and the spring force is balanced with the magnetic attraction force. Therefore, by controlling the energization amount to the coil 49 to be an intermediate value between on and off by, for example, duty control, the magnetic attraction force that attracts the armature 46 to the fixed core 45 side can be changed.

  On the other hand, the opposed surfaces 45 a and 46 a of the fixed core 45 and the armature 46 are formed as tapered surfaces that increase in diameter as they move away from the output chamber 35.

  When the opposing surfaces 45a and 46a of the fixed core 45 and the armature 46 are formed in a tapered surface in this way, the opposing distance between the fixed core 45 and the armature 46 (in a direction perpendicular to the tapered surface) compared to the axial stroke amount of the armature 46. The change in the suction force generated between the opposed surfaces 45a and 46a is smaller than the change in the axial stroke. Moreover, the suction force that actually acts in the axial direction is a sine component of the suction force generated between the opposing surfaces 45a and 46a, and with respect to the change in the suction force between the opposing surfaces 45a and 46a as the taper surface angle becomes acute. The change in the suction force in the axial direction is reduced.

  As a result, as shown by the solid line in FIG. 4, the suction force between the fixed core 45 and the armature 46 can be made substantially flat in the practical range between the fully closed and fully opened states of the valve portion 35. On the other hand, when the opposing surfaces of the fixed core 45 and the armature 46 are flat surfaces perpendicular to the axial direction, the opposing distance between the fixed core 45 and the armature 46 changes proportionally according to the axial stroke of the valve shaft 34. Therefore, as shown by the chain line in FIG. 4, the suction force between the fixed core 45 and the armature 46 changes greatly even in the practical range.

  In this way, the normally open solenoid valve 15A is on / off controlled and duty controlled to give an intermediate current between on and off so as to linearly change the hydraulic pressure on the left front wheel brake BA side. The other normally open solenoid valves 15B to 15D are configured similarly to the normally open solenoid valve 15A. On the other hand, the normally closed solenoid valves 16A to 16D are only on / off controlled. Thus, in the increase mode of the anti-lock brake control, the brake force of each of the wheel brakes BA to BD can be increased rapidly by turning on the normally open solenoid valves 15A to 15D, and the normally open type is also normally open. It is possible to moderately increase the brake force of each wheel brake BA to BD by duty-controlling the type solenoid valves 15A to 15D.

  In FIG. 5, the controller C uses the wheel speeds of the left front wheel WA, the right front wheel WC, the right rear wheel WB, and the left rear wheel WD, which are individually detected by the wheel speed detection means 6A, 6C, 6B, 6D. Wheel-corresponding vehicle speed estimating means 55A, 55C, 55B, 55D for estimating the wheel-corresponding vehicle speed for each of WA to WD, vehicle speed detecting means 56 for detecting the vehicle speed, and deceleration detecting means for detecting the deceleration of the vehicle 57, a friction coefficient determining means 58 for determining the level of the friction coefficient of the traveling road surface based on the deceleration detected by the deceleration detecting means 57, the wheel speed detected by the wheel speed detecting means 6A and the vehicle body speed. The left front wheel locking tendency determination means 59A for determining the locking tendency of the left front wheel WA based on the vehicle body speed detected by the detection means 56, and the wheel speed detected by the wheel speed detection means 6C. In addition, the right front wheel lock tendency determination means 59C for determining the lock tendency of the right front wheel WC based on the vehicle body speed detected by the vehicle body speed detection means 56, the wheel speed detected by the wheel speed detection means 6B, and the vehicle body speed. A right rear wheel locking tendency determination means 59B for determining the locking tendency of the right rear wheel WB based on the vehicle body speed detected by the detection means 56, the wheel speed detected by the wheel speed detection means 6D, and the vehicle body speed detection means. The left rear wheel lock tendency determining means 59D for determining the lock tendency of the left rear wheel WD based on the vehicle body speed detected at 56, and the wheel corresponding vehicle body speed estimated by the wheel corresponding vehicle body speed estimating means 55A to 55D, respectively. The maximum deviation calculating means 60 for calculating the difference between the maximum value and the minimum value of the vehicle, and the friction coefficient of the road surface has changed suddenly from a low friction coefficient to a high friction coefficient. The friction coefficient sudden change determination means 61 that can be disconnected, and basically the wheel brake for the front left wheel according to the determination result by the left front wheel lock tendency determination means 59A and the determination result of the friction coefficient determination means 58. The left front wheel control mode setting means 62A for determining the control mode for increasing / decreasing the braking force of the BA, basically the determination result by the right front wheel lock tendency determination means 59C and the determination result of the friction coefficient determination means 58. Accordingly, the determination result by the right front wheel control mode setting means 62C for determining the control mode for increasing / decreasing the braking force of the right front wheel brake BC, basically the determination result by the right rear wheel lock tendency determination means 59B and the friction. The right rear determines the control mode for increasing or decreasing the braking force of the right rear wheel brake BB according to the determination result of the coefficient determining means 58. The braking force of the wheel brake BD for the left rear wheel is basically determined according to the determination result by the wheel control mode setting means 62B and the determination result by the left rear wheel lock tendency determination means 59D and the determination result by the friction coefficient determination means 58. Control of the operation of the left front wheel brake pressure adjusting means 17A in the actuator 1 according to the control mode set by the left rear wheel control mode setting means 62D for determining a control mode for increasing and decreasing and the left front wheel control mode setting means 62A. Actuator control means 63A for the left front wheel, and actuator control means 63C for the right front wheel that controls the operation of the right front wheel brake pressure adjusting means 17C in the actuator 1 according to the control mode set by the control mode setting means 62C for the right front wheel. In accordance with the control mode set by the right rear wheel control mode setting means 62C. The left rear wheel actuator control means 63B for controlling the operation of the right rear wheel brake pressure adjusting means 17B in the actuator 1 and the left rear wheel control mode setting means 62D according to the control mode set by the left rear wheel control mode setting means 62D. Left rear wheel actuator control means 63D for controlling the operation of the rear wheel brake pressure adjusting means 17D.

  Based on the wheel speed of the left front wheel WA detected by the wheel speed detecting means 6A, the wheel-corresponding vehicle body speed estimating means 55A uses the wheel deceleration so that the vehicle speed does not exceed the set deceleration in the deceleration process. The vehicle speed is estimated by using the wheel acceleration so that the acceleration does not exceed the set acceleration in the acceleration process, and the wheel speed changes as shown in FIG. The vehicle body speed is estimated by the wheel corresponding vehicle body speed estimating means 55A.

  The wheel corresponding vehicle body speed estimating means 55C, 55B, 55D is also the same as the wheel corresponding vehicle body speed estimating means 55A, and the right front wheel WC, the right rear wheel WB and the left detected by the wheel speed detecting means 6C, 6B, 6D. Based on the wheel speed of the rear wheel WD, the wheel corresponding vehicle body speed for each of the right front wheel WC, the right rear wheel WB, and the left rear wheel WD is estimated.

  The vehicle body speed detecting means 56 selects the highest value of the wheel corresponding vehicle body speeds estimated by the wheel corresponding vehicle body speed estimating means 55A to 55D as the vehicle body speed, and the deceleration detecting means 57 is the vehicle body speed detecting means 56. A vehicle deceleration is obtained by differentiating the vehicle body speed obtained in (1). Further, the friction coefficient discriminating means 58 discriminates the level of the friction coefficient of the traveling road surface based on the vehicle deceleration obtained by the deceleration detecting means 57.

  In consideration of the turning state of the vehicle, the vehicle body speed obtained by the vehicle body speed detecting means 56 may be corrected for turning based on the wheel speeds of the right rear wheel WB and the left rear wheel WD as driven wheels.

  The left front wheel lock tendency determining means 59A, the right front wheel lock tendency determining means 59C, the right rear wheel lock tendency determining means 59B and the left rear wheel lock tendency determining means 59D are detected by the respective wheel speed detecting means 6A to 6D. The locking tendency of the left front wheel WA, the right front wheel WC, the right rear wheel WB and the left rear wheel WD is determined based on the wheel speed and the vehicle body speed detected by the vehicle body speed detection means 56, respectively.

  The left front wheel control mode setting means 62A, the right front wheel control mode setting means 62C, the right rear wheel control mode setting means 62B, and the left rear wheel control mode setting means 62D are the left front wheel lock tendency determination means 59A, the right front wheel, The left front wheel brake BA, the right front wheel brake BC, the right rear wheel according to the determination results by the lock tendency determination means 59C, the right rear wheel lock tendency determination means 59B, and the left rear wheel lock tendency determination means 59D The control mode is set by switching the brake force increasing mode, holding mode and decreasing mode of the wheel brake BB for the left rear wheel and the wheel brake BD for the left rear wheel. The rapid increase mode when it is determined that the coefficient of friction is high according to the determination result of the means 58 and the slow speed when it is determined that the coefficient of friction is low. Switch the pressure mode.

  Further, the friction coefficient sudden change judging means 61 applies to all wheels, that is, the left front wheel WA, the right front wheel WC, the right rear wheel WB, and the left rear wheel WD based on the fact that the friction coefficient judging means 58 judges that the coefficient of friction is low. In a state where the corresponding left front wheel control mode setting means 62A, right front wheel control mode setting means 62C, right rear wheel control mode setting means 62B and left rear wheel control mode setting means 62D are selecting the slowly increasing mode. The elapsed time of the slow increase mode of at least one wheel is a predetermined time, for example, 400 msec or more, and the vehicle deceleration detected by the deceleration detection means 57 is reduced to a threshold value for determination (eg, −0.3 G). In addition, the calculated value of the maximum deviation calculating means 60, that is, the maximum value of the wheel-corresponding vehicle speed estimated by the wheel-corresponding vehicle speed estimating means 55A to 55D, respectively. Friction coefficient is determined to have changed drastically to the high friction coefficient of a low friction coefficient when the difference between the minimum value is less than the reference value, for example 5km / h.

  Further, the left front wheel control mode setting means 62A, the right front wheel control mode setting means 62C, the right rear wheel control mode setting means 62B, and the left rear wheel control mode setting means 62D have the friction coefficient determining means 58 having a low friction coefficient. The friction coefficient sudden change determination means 61 determines that the friction coefficient of the running road surface has suddenly changed from the low friction coefficient to the high friction coefficient in the state where the slow increase mode is selected based on the determination that there is. In response, the control mode is switched from the slow increase mode to the rapid increase mode.

  Next, the operation of this embodiment will be described. The left front wheel brake BA, the right front wheel brake BC, the right rear wheel brake BB, and the left rear wheel brake BD are controlled by the anti-lock brake control. The left front wheel control mode setting means 59A, the right front wheel control mode setting means 59C, the right rear wheel control mode setting means 59B, and the left rear wheel control mode setting means 59D for determining the control mode are in the increase mode. Depending on the determination result of the friction coefficient determination means 58, there are sometimes switching between a sudden increase mode when it is determined to be a high friction coefficient and a slow increase mode when it is determined that it is a low friction coefficient. In a state where the mode of moderate increase is selected by the means 59A to 59D, the friction coefficient sudden change determination means 61 is provided with at least one vehicle. The elapsed time of the slow increase mode is equal to or longer than a predetermined time, the vehicle deceleration detected by the deceleration detection means 57 exceeds the threshold for determination toward the deceleration side, and the vehicle body speed estimation means 55A to 55D corresponding to each wheel. When the difference between the estimated maximum and minimum wheel-corresponding vehicle speeds is less than the reference value, it is determined that the friction coefficient has suddenly changed from a low friction coefficient to a high friction coefficient.

  That is, the friction coefficient sudden change determination means 61 determines that the pressure increase is insufficient because the elapsed time of the slow increase mode of at least one wheel is equal to or longer than the predetermined time, and the maximum value and minimum value of the vehicle speed corresponding to the wheel. It is determined that the wheel speeds of the plurality of wheels are changing almost synchronously because the difference between the two is less than the reference value, and in such a state, the vehicle deceleration exceeds the threshold for determination toward the deceleration side. It is judged that the friction coefficient of the road surface has changed abruptly from the low friction coefficient to the high friction coefficient, and it is possible to set a threshold for judgment strictly, and the friction coefficient of the road surface is changed from the low friction coefficient to the high friction coefficient. It is possible to quickly determine with a simple calculation content that the coefficient has rapidly changed.

  Thus, when the friction coefficient sudden change judging means 61 judges that the friction coefficient of the running road surface has suddenly changed from the low friction coefficient to the high friction coefficient, the left front wheel control mode setting means 62A, the right front wheel use The control mode setting means 62C, the right rear wheel control mode setting means 62B, and the left rear wheel control mode setting means 62D switch the control mode from the slow increase mode to the rapid increase mode. An increase in the braking distance can be avoided, and excellent braking performance can be ensured to shorten the braking distance.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, when the vehicle turns, a difference in wheel speed occurs between the turning inner wheel and the turning outer wheel based on the difference in turning radius. Therefore, the friction coefficient sudden change determination means 61 uses the reference value for the difference between the maximum and minimum wheel-corresponding vehicle speeds. May be corrected so as to increase as the turning radius becomes smaller (the steering angle becomes larger) in accordance with the turning amount. Further, the reference value may be a constant value, and the wheel-corresponding vehicle body speed of each wheel may be corrected according to the turning amount so as to compensate for the influence of the difference in turning radius.

It is a figure which shows the drive system and brake system of a front-wheel drive vehicle. It is a hydraulic system diagram which shows the composition of a brake fluid pressure control device. It is a longitudinal cross-sectional view of a normally open type solenoid valve. It is a figure which shows the suction force change with respect to the stroke change of a valve shaft. It is a block diagram which shows the structure of a controller. It is a figure which shows the relationship between the vehicle body speed corresponding to a wheel, and a wheel speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Actuator 6A, 6B, 6C, 6D ... Wheel speed detection means 55A, 55B, 55C, 55D ... Wheel corresponding vehicle body speed estimation means 56 ... Body speed detection means 57 ... Deceleration detection Means 58... Friction coefficient discrimination means 59A, 59B, 59C, 59D... Lock tendency judgment means 61... Friction coefficient sudden change judgment means 62A, 62B, 62C, 62D... Control mode setting means 63A, 63B , 63C, 63D ... Actuator control means BA, BB, BC, BD ... Wheel brake WA ... Left front wheel WB as a wheel ... Right rear wheel WC as a wheel ... Right front wheel as a wheel WD: Left rear wheel as a wheel

Claims (1)

  An actuator (1) capable of individually adjusting a braking force exerted by a wheel brake (BA, BB, BC, BD) mounted on each of a plurality of wheels (WA, WB, WC, WD); Wheel speed detecting means (6A, 6B, 6C, 6D) for individually detecting the wheel speed of WD); body speed detecting means (56) for detecting the body speed; and deceleration detection for detecting the deceleration of the vehicle Means (57); friction coefficient determination means (58) for determining the level of the friction coefficient of the road surface based on the deceleration detected by the deceleration detection means (57); and the wheel speed detection means (6A to 6A). 6D) and a lock tendency determination means (59A, 59B) for determining a lock tendency for each wheel (WA to WD) based on the wheel speed detected by the vehicle speed and the vehicle body speed detection means (56). 5 C, 59D); and a control mode for increasing or decreasing the braking force is determined for each wheel brake (BA to BD) according to the determination result by the lock tendency determination means (59A to 59D) and the control mode is increased. Control mode setting for switching between a rapid increase mode when it is determined to be a high friction coefficient and a slow increase mode when it is determined to be a low friction coefficient according to the determination result of the friction coefficient determination means (58). Means (62A, 62B, 62C, 62D); actuator control means (63A, 63B, 63C, 63D) for controlling the operation of the actuator (1) according to the control mode set by the control mode setting means (62A to 62D) And an anti-lock brake control device for a vehicle comprising the wheel speed detecting means (6A to 6D). Wheel corresponding vehicle body speed estimating means (55A, 55B, 55C, 55D) for estimating the wheel corresponding vehicle speed for each of the wheels (WA to WD) based on the detected wheel speed; and the friction coefficient determining means (58). In the state where the slow increase mode is selected for all the wheels (WA to WD) based on determining that is a low friction coefficient, the elapsed time of the slow increase mode of at least one wheel is a predetermined time or more. The vehicle speed detected by the deceleration detection means (57) exceeds the threshold value for determination toward the deceleration side, and the vehicle body speed corresponding to each wheel estimated by the vehicle speed estimation means (55A to 55D) corresponding to each wheel. Friction coefficient sudden change judging means (61) for judging that the friction coefficient has suddenly changed from the low friction coefficient to the high friction coefficient when the difference between the maximum value and the minimum value of the speed is less than the reference value; control The mode setting means (62A to 62D) is in a state in which the slow increase mode is selected for all the wheels (WA to WD) based on the fact that the friction coefficient determination means (58) determines that the friction coefficient is low. The control mode of all the wheels (WA to WD) is gradually increased according to the fact that the friction coefficient sudden change judging means (61) judges that the friction coefficient of the road surface has suddenly changed from the low friction coefficient to the high friction coefficient. An antilock brake control device for a vehicle, wherein the mode is switched from a mode to a sudden increase mode.

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