JP2008120129A - Behavior control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a behavior control device of a vehicle capable of restraining deterioration of the ride comfort or steering stability of a vehicle even when a rim width of a wheel is changed for controlling the behavior of the vehicle. <P>SOLUTION: This behavior control device of a vehicle comprises radius set means for setting radii of right and left wheels, radius change means 7A, 7B for changing the radii of the wheels according to a rim width of the wheel, and suspension characteristic change means 8a, 8a for changing characteristics of the suspension. When the radii of the left wheel and/or the right wheel are changed by the radius change means 7A, 7B according to the radii set by the radius set means, the characteristics of the suspension are changed by the suspension characteristic change means 8a, 8a according to the change in rim width of the wheel with the radius change means 7A, 7B. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle behavior control device capable of turning a vehicle without turning wheels.

  In general, in a vehicle, a front wheel is steered according to an operation of a steering wheel by a driver, and the vehicle turns. When the front wheel is steered, the direction in which the front wheel is facing and the direction in which the vehicle is actually facing are shifted, and the tire rotates while slipping by the angle (slip angle). This slip angle generates resistance (cornering resistance) on the tire ground contact surface, and cornering force is generated in the direction perpendicular to the traveling direction due to the cornering resistance. This cornering force becomes a turning force, and the vehicle turns.

However, when the vehicle is turned by turning the wheels (tires), cornering resistance is generated every time the vehicle is turned, and thus the driving force is lost due to this resistance. In addition, the fender is cut out in a semicircular shape to prevent the tire from interfering with the fender during steering, so air enters the cut-out part, and the air that enters the air becomes turbulent and air resistance is reduced. appear. These factors make fuel consumption worse. Furthermore, in order to secure the space for turning the tire, the tire house has a structure that protrudes greatly into the engine room and the cabin, so that the space of the engine room and the cabin is limited. Further, when a wheel is steered and turned, a roll is generated in which the outer wheel side of the vehicle sinks due to centrifugal force. Therefore, various tunings of a suspension such as a stabilizer and an absorber are required to suppress the roll. Therefore, Patent Document 1 discloses a vehicle behavior control device that turns a vehicle by making the radii of wheels different between a right wheel and a left wheel. In this vehicle behavior control device, the rim width is changed by sliding at least one of the inner wheel and the outer wheel in the vehicle width direction by an actuator, and the radius of the wheel is changed.
Japanese Patent Application No. 2005-360667

  The vehicle behavior control apparatus described above changes the rim width of the wheel of at least one of the left and right wheels in order to turn the vehicle. Therefore, when the vehicle turns, the center position (vehicle width direction) of at least one wheel changes, and the tread of the vehicle changes. Accordingly, since one end of the suspension is attached to the vehicle body, the distance between the attachment position and the center position of the wheel changes during turning of the vehicle. As a result, the load input to the suspension changes. Also, in the suspension, characteristics such as the damping force of the absorber and the spring constant of the spring are usually set optimally according to the vehicle, assuming an input load and the like. For this reason, if the load input to the suspension changes while the vehicle is turning, the posture of the vehicle may change or the behavior (transient characteristics) may deteriorate, which may reduce the riding comfort and handling stability of the vehicle. .

  Therefore, an object of the present invention is to provide a vehicle behavior control device that suppresses a decrease in the riding comfort and steering stability of a vehicle even when the rim width of the wheel is changed in order to control the behavior of the vehicle.

  The vehicle behavior control apparatus according to the present invention includes a radius setting means for setting the radii of the left and right wheels, a radius changing means for changing the radius of the wheel according to the rim width of the wheels, and a suspension characteristic changing means for changing the characteristics of the suspension. When the radius of the left wheel or / and the right wheel is changed by the radius changing means according to the radius set by the radius setting means, the suspension is changed by the suspension characteristic changing means according to the change of the rim width of the wheel by the radius changing means. It is characterized by changing the characteristics of

  In this vehicle behavior control apparatus, the radius setting means sets the radii of the left and right wheels in accordance with the turning of the vehicle, the traveling state of the vehicle, the loading state of the vehicle, the road surface state, and the like. For example, when turning a vehicle, if the left and right wheels rotate at the same rotational speed by providing a difference in the wheel radius between the left and right wheels, the wheel with the smaller radius is the inner ring and the wheel with the larger side is the outer wheel. The vehicle turns. And in a behavior control apparatus, the rim width | variety of a wheel is changed according to the radius of each wheel set by the radius change means, and the radius of each wheel is changed. Changing the wheel rim width changes the tire width, so the tire height changes and the tire outer diameter (wheel radius) changes. Thus, in this behavior control device, the flatness of the tire is changed and the radius of the wheel is changed by changing the rim width of the wheel. By applying this to turning the vehicle, it is possible to turn the vehicle without turning the wheels. Further, in this behavior control device, when the rim width of the wheel is changed, the suspension characteristics change means changes the characteristics of the suspension (damping force characteristics, spring characteristics, etc.) according to the change of the rim width. When the rim width of the wheel changes, the center position (tread) of the wheel in the vehicle width direction changes. Due to this change, the distance between the attachment position of the suspension to the vehicle body and the center position of the wheel in the vehicle width direction changes, so the load input to the suspension changes. Therefore, the characteristics of the suspension are changed according to the change in the load. As described above, in this behavior control device, even when the rim width of the wheel is changed, the suspension characteristic changes to a characteristic corresponding to the change in the tread at that time, so that the ride comfort and steering stability of the vehicle are reduced. Can be suppressed.

  In the vehicle behavior control apparatus according to the present invention, the suspension characteristic changing means may be configured to change the damping force characteristic of the suspension.

  In this vehicle behavior control device, when the rim width of the wheel is changed, the suspension damping characteristic is changed by the suspension characteristic changing means in accordance with the change in the rim width. As described above, in this behavior control apparatus, the damping force is increased or decreased so as to correspond to the change in the load input to the suspension.

  In the vehicle behavior control apparatus of the present invention, the suspension characteristic changing means may be configured to change the spring characteristic of the suspension.

  In this vehicle behavior control apparatus, when the rim width of the wheel is changed, the spring characteristic of the suspension is changed according to the change of the rim width by the suspension characteristic changing means. As described above, in this behavior control device, the strength of the spring is adjusted so as to cope with a change in the load input to the suspension.

  The vehicle behavior control apparatus of the present invention includes a turning amount setting means for setting the turning amount of the vehicle, and the radius setting means increases the turning amount set by the turning amount setting means as the turning outer wheel with respect to the radius of the turning inner wheel. The radius may be increased.

  In this vehicle behavior control device, the turning amount of the vehicle is set by the turning amount setting means. Examples of the turning amount include a steering amount by a driver's steering operation, a steering amount by automatic steering, a steering amount by lane keeping, and a steering amount for stabilizing vehicle behavior. In the behavior control device, the radius setting means uses the turning direction side wheel as the turning inner wheel and the other side wheel as the turning outer wheel, and increases the radius of the turning outer wheel relative to the radius of the turning inner wheel as the turning amount increases. Sets the wheel radius. In this way, the behavior control device controls the relative radius ratio between the turning inner wheel and the turning outer wheel according to the set turning amount, thereby turning the vehicle by the target turning amount without turning the wheels. Can be made.

  In the vehicle behavior control apparatus according to the present invention, the radius changing means includes a wheel including an inner wheel arranged on the inner side in the vehicle width direction and an outer wheel arranged on the outer side, a rim of the inner wheel, and a rim of the outer wheel. It is good also as a structure provided with the pneumatic tire respectively couple | bonded and the actuator which slides at least one of an inner wheel and an outer wheel in a vehicle width direction.

  The radius changing means of the vehicle behavior control device has a structure in which a wheel includes an inner wheel and an outer wheel, and at least one of the inner wheel and the outer wheel can slide in the vehicle width direction. In the radius changing means, the pneumatic tire is coupled to the rim of the inner wheel and the rim of the outer wheel, respectively. Therefore, in the radius changing means, the rim width of the wheel is changed by sliding at least one of the inner wheel and / or the outer wheel by the actuator, and the width of the pneumatic tire is changed in accordance with the change of the rim width. When the width of the pneumatic tire changes, the height of the pneumatic tire changes, so the radius of the wheel changes. Thus, in this behavior control device, the radius of the wheel can be changed with a simple configuration in which the rim width of the wheel is changed by sliding between the inner wheel and the outer wheel.

  Even when the rim width of the wheel is changed to control the behavior of the vehicle, the present invention reduces the ride comfort and steering stability of the vehicle by changing the suspension characteristics according to the change of the rim width. Can be suppressed.

  Embodiments of a vehicle behavior control apparatus according to the present invention will be described below with reference to the drawings.

  In the present embodiment, the present invention is applied to a behavior control device mounted on a vehicle driven by a rear wheel by an engine. In the behavior control apparatus according to the present embodiment, the rim width of the wheel is changed by sliding the outer wheel with respect to the inner wheel in all the wheels, and the radius of the wheel is changed by changing the rim width. And in the behavior control apparatus which concerns on this Embodiment, a vehicle turning, vehicle attitude | position adjustment, aerodynamic resistance reduction, etc. are performed by changing the radius of each wheel. In addition, the behavior control apparatus according to the present embodiment includes an electromagnetic variable absorber in each suspension, and changes the damping force characteristics of the suspension by the electromagnetic variable absorber.

  With reference to FIGS. 1-5, the behavior control apparatus 1 which concerns on this Embodiment is demonstrated. FIG. 1 is a configuration diagram of a behavior control apparatus according to the present embodiment. FIG. 2 is a partially broken front view of the wheel (front wheel side) of the behavior control device according to the present embodiment. FIG. 3 is a front sectional view of the shaft delivery mechanism on the right wheel side according to the present embodiment. FIG. 4 is a principle diagram of turning by the difference between the left and right radii according to the present embodiment. FIG. 5 is a schematic diagram when the vehicle at the time of vehicle turning according to the present embodiment is viewed from the rear.

  The behavior control device 1 controls various vehicle behaviors such as vehicle turning by changing the radius of each wheel independently and changing the damping force of the suspension. Therefore, in the behavior control apparatus 1, the wheel is composed of an inner wheel and an outer wheel, and the outer wheel slides with respect to the inner wheel, thereby changing the rim width of the wheel and changing the flatness of the tire. In particular, the behavior control device 1 changes the damping force of the suspension according to the change in the tread in order to improve the steering stability and riding comfort of the vehicle when the rim width (and thus the tread) is changed. The behavior control device 1 includes a steering angle sensor 2, a vehicle speed sensor 3, a suspension stroke sensor 4, a seating sensor 5, a connecting shaft stroke sensor 6, a right front wheel 7A, a left front wheel 7B, a right rear wheel 7C, a left rear wheel 7D, A connection mechanism between the left and right wheels, a right front suspension 8A, a left front suspension 8B, a right rear suspension 8C, a left rear suspension 8D, and an ECU [Electronic Control Unit] 9 are provided. In the present embodiment, the right front wheel 7A, the left front wheel 7B, the right rear wheel 7C, and the left rear wheel 7D correspond to radius changing means described in the claims.

  The steering angle sensor 2 is a sensor that detects the steering angle of the steering wheel input by the driver. The steering angle sensor 2 transmits the detected steering angle to the ECU 9 as a steering angle signal. The steering angle indicated by the steering angle signal includes size information and steering direction information.

  The vehicle speed sensor 3 is a sensor that detects the speed of the vehicle. The vehicle speed sensor 3 transmits the detected vehicle speed to the ECU 9 as a vehicle speed signal.

  The suspension stroke sensor 4 is a sensor that detects the stroke of the suspension 8 in each wheel. The suspension stroke sensor 4 transmits the detected stroke to the ECU 9 as a suspension stroke signal. Although one suspension stroke sensor 4 is not depicted in FIG. 1, each suspension wheel is provided, and the ECU 9 receives a suspension stroke signal from the suspension stroke sensor 4 of each wheel. The

  The seating sensor 5 is a sensor that detects whether a person is sitting in each seat. The seating sensor 5 transmits the detected seating information to the ECU 9 as a seating signal. In FIG. 1, although one seating sensor 5 is not drawn, each seat is provided, and a seating signal from each seating sensor 5 is transmitted to the ECU 9.

  The connecting shaft stroke sensor 6 is a sensor that detects a stroke in the vehicle width direction of the connecting shaft 7m in each wheel described below. As shown in FIG. 3, the connecting shaft stroke sensor 6 is provided in the shaft sending mechanism portion 7 c and detects the stroke amount of the outer connecting shaft 7 i in the vehicle width direction. The connecting shaft stroke sensor 6 transmits the detected stroke amount to the ECU 9 as a connecting shaft stroke signal. Although one connecting shaft stroke sensor 6 is not illustrated in FIG. 1, each wheel is provided with a connecting shaft stroke signal from the connecting shaft stroke sensor 6 of each wheel. Each is sent.

  The right front wheel 7A, the left front wheel 7B, the right rear wheel 7C, and the left rear wheel 7D have the same configuration. The wheel 7 mainly includes a wheel 7a, a tire 7b, and a shaft delivery mechanism portion 7c. In each wheel 7, the outer wheel 7e is moved along the vehicle width direction by the shaft delivery mechanism 7c, and the rim width of the wheel 7a is changed. As a result, the cross-sectional width of the tire 7b changes, and the height of the tire 7b changes in accordance with the change in the cross-sectional width (therefore, the flatness ratio of the tire 7b (= tire height / tire cross-sectional width) changes). The outer diameter (wheel diameter) of the tire 7b changes. Here, the mechanism of the driven wheel (front wheel) will be described, but the drive wheel (rear wheel) has the same configuration as the driven wheel.

  The wheel 7a includes an inner wheel 7d disposed on the inner side in the vehicle width direction and an outer wheel 7e disposed on the outer side. The inner wheel 7d has a circular concave shape, a circular hole is formed at the center of the concave bottom, and a rim is provided on the inner side in the vehicle width direction. The outer wheel 7e is a circular concave shape having a slightly larger diameter than the inner wheel 7d, a circular hole is formed at the center of the bottom of the concave shape, and a rim is provided on the outer side in the vehicle width direction. The inner wheel 7d is fitted inside the outer wheel 7e, and the outer peripheral surface of the inner wheel 7d and the inner peripheral surface of the outer wheel 7e are coupled by a spline mechanism. Therefore, the outer wheel 7e can slide with respect to the inner wheel 7d by a predetermined length, and the wheel 7a can change the rim width (the distance between the rim of the inner wheel 7d and the rim of the outer wheel 7e). Further, the inner wheel 7d and the outer wheel 7e are rotated synchronously together by a spline mechanism.

  In the tire 7b, beads at both ends are coupled to the rim of the inner wheel 7d and the rim of the outer wheel 7e, respectively. Examples of the coupling method include fitting and adhesion. Inside the tire 7b, reinforcing materials 7f,... Are attached along the inner surface at a plurality of locations (for example, 8 locations, 16 locations). The reinforcing members 7f are shaped like a hair band having a predetermined width, and are arranged at regular intervals along the circumferential direction of the tire 7b. The reinforcing material 7f is formed of, for example, a resin or a wire. Further, the tire 7b is provided with an airtight tube 7g inside the reinforcing members 7f,. The tire 7b changes its cross-sectional width in accordance with the change in the rim width of the wheel 7a. The tire height decreases as the cross-sectional width increases, and the tire height increases as the cross-sectional width decreases. In accordance with the change in the shape of the tire 7b, the shapes of the reinforcing members 7f, ... and the tube 7g also change.

  Although a mechanism in the front wheel will be described as a coupling mechanism between the left and right wheels, the rear wheel has the same configuration as the front wheel. The right front wheel 7A and the left front wheel 7B are connected by a connecting shaft 7m and rotate at the same rotational speed. The front wheels 7A and 7B each have a connecting shaft 7m rotatably supported by a shaft delivery mechanism 7c.

  The connecting shaft 7m includes a central connecting shaft 7n, left and right outer connecting shafts 7i and 7i, and left and right constant velocity joints 7o and 7o. The central connecting shaft 7n, the outer connecting shafts 7i, 7i and the constant velocity joints 7o, 7o are arranged on the same axis between the front wheel 7A and the front wheel 7B. The central connecting shaft 7n is rotatably attached to the vehicle body BD, and each end thereof is coupled to one end of the left and right constant velocity joints 7o and 7o. One end of each outer connecting shaft 7i, 7i is coupled to the other end of the constant velocity joints 7o, 7o. Since the constant velocity joints 7o and 7o rotate the central connecting shaft 7n and the outer connecting shafts 7i and 7i at the same rotational speed (because the relative rotational freedom is restricted), the left and right outer connecting shafts are connected via the central connecting shaft 7n. 7i and 7i rotate at the same rotation speed. Therefore, the connecting shaft 7m rotates at the same rotational speed over the entire region.

  In the case of drive wheels in a vehicle driven by a single engine or motor, the connecting shaft 7m corresponds to a drive shaft, and the drive shaft includes a central drive shaft, left and right outer drive shafts, and left and right constant velocity joints. Then, the driving force by the engine is transmitted to the central drive shaft through the mission and final mechanism, and the central drive shaft rotates. As the central drive shaft rotates, the left and right outer drive shafts rotate at the same rotational speed via the left and right constant velocity joints. Therefore, the drive shaft rotates at the same rotational speed over the entire region in accordance with the driving force of the engine. In the case of the in-wheel motor type drive system, the left and right wheels can be controlled to the same rotational speed by the in-wheel motor of each wheel, so the mechanism for rotating the left and right wheels as described above at the same rotational speed. There is no need.

  The other end of the outer connecting shaft 7i has a bolt shape. A circular hole through which the outer connecting shaft 7i is fitted is formed at the center of the concave bottom of the outer wheel 7e. The other ends of the outer connecting shafts 7i and 7i are fitted into the holes of the outer wheels 7e and 7e, and are bolted and fixed to the outer wheels 7e and 7e by nuts 7j and 7j. Accordingly, the left and right outer wheels 7e, 7e are connected by the connecting shaft 7m and rotate at the same rotational speed. Further, the outer connecting shaft 7i is inserted through the inside of the shaft delivery mechanism portion 7c, and expands and contracts in the vehicle width direction according to the slide along the vehicle width direction of the outer wheel 7e.

  In the constant velocity joint 7o, the ball bearing in the joint slides in the expansion / contraction direction (vehicle width direction). As a result, the constant velocity joint 7o absorbs the expansion and contraction of the outer connecting shaft 7i and the change in the relative distance between the left and right wheels 7A and 7B (change due to the movement of the left and right wheels 7A and 7B due to road disturbance or body movement). .

  In the behavior control device 1, the right front wheel 7A and the left front wheel 7B on the driven wheel side, and the right rear wheel 7C and the left rear wheel 7D on the drive wheel side are configured to rotate at the same rotational speed. Therefore, by providing a difference between the diameters of the left and right wheels, the vehicle turns to the smaller diameter side.

  The shaft delivery mechanism portion 7c includes a bearing 7r, a rack 7s, a pinion 7t, and an actuator 7u (a motor 7v and a speed reduction mechanism 7w) in a cylindrical case 7q. The shaft delivery mechanism portion 7c is disposed inside the inner wheel 7d, and the outer connecting shaft 7i is inserted through the inside. In the shaft delivery mechanism portion 7c, the outer connecting shaft 7i is rotatably supported, and the outer connecting shaft 7i is expanded and contracted outward in the vehicle width direction by the motor torque (rotational driving force) of the motor 7v, so that the outer wheel 7e is extended. Slide and move with respect to the inner wheel 7d.

  The outer connecting shaft 7i is inserted into the inner race of the bearing 7r, and the outer connecting shaft 7i is attached. Therefore, the outer connecting shaft 7i is rotatable. One surface of the rack 7s (the surface opposite to the surface of the rack gear) is attached to a part of the outer race of the bearing 7r. Accordingly, the outer connecting shaft 7i is coupled to the rack 7s via the bearing 7r. The bearing 7r and the rack 7s are provided in the case 7q so as to be movable along the vehicle width direction.

  A pinion 7t is disposed on the other surface side of the rack 7s, and the pinion gear meshes with the rack gear. The rotational driving force of the motor 7v is transmitted to the pinion 7t via the speed reduction mechanism 7w. The pinion 7t, the motor 7v, and the speed reduction mechanism 7w are provided in a fixed position in the case 7q.

  The rotation of the motor 7v is transmitted to the pinion 7t via the speed reduction mechanism 7w, and rotates the pinion 7t. The rotation of the pinion 7t is transmitted to the rack 7s, and moves the rack 7s along the vehicle width direction. As the rack 7s moves, the bearing 7r moves, and the outer connecting shaft 7i expands and contracts outward in the vehicle width direction.

  Further, the outer peripheral portion 7k of the case 7q of the shaft delivery mechanism portion 7c protrudes outward in the vehicle width direction. The outer peripheral portion 7k extends to a central hole of the inner wheel 7d, and is attached to the inner wheel 7d via a bearing 7l. Therefore, the position of the inner wheel 7d does not move with respect to the shaft delivery mechanism portion 7c, but is rotatable with respect to the shaft delivery mechanism portion 7c.

  One end portion of the electromagnetic variable absorber 8a of the suspension 8 and one end portion of the lower arm 8c are attached to the inner end portion of the shaft sending mechanism portion 7c in the vehicle width direction. The other end of the electromagnetic variable absorber 8a and the other end of the lower arm 8c are attached to the vehicle body BD. Accordingly, the shaft delivery mechanism 7c (and thus the inner wheel 7d) is attached to the vehicle body BD via the electromagnetic variable absorber 8a and the lower arm 8c.

  When the rack 7s and the bearing 7r move to the outside in the vehicle width direction through the speed reduction mechanism 7w and the pinion 7t by the rotational driving force of the motor 7v, the outer connecting shaft 7i extends to the outside in the vehicle width direction, and the outer wheel 7e becomes the inner wheel. It slides outward in the vehicle width direction with respect to 7d, the rim width of the wheel 7a is widened, and the height of the tire 7b is lowered. In this case, since the center position of the wheel 7 in the vehicle width direction moves to the outside in the vehicle width direction, the tread of the vehicle becomes wide. On the other hand, when the rack 7s and the bearing 7r move inward in the vehicle width direction via the speed reduction mechanism 7w and the pinion 7t by the rotational driving force of the motor 7v, the outer connecting shaft 7i contracts inward in the vehicle width direction, and the outer wheel 7e It slides inward in the vehicle width direction with respect to the inner wheel 7d, the rim width of the wheel 7a is narrowed, and the height of the tire 7b is increased. In this case, since the center position of the wheel 7 in the vehicle width direction moves inward in the vehicle width direction, the tread of the vehicle becomes narrow. At this time, the constant velocity joint 7o absorbs expansion and contraction of the outer connecting shaft 7i.

  The right front suspension 8A, the left front suspension 8B, the right rear suspension 8C, and the left rear suspension 8D are of the MacPherson strut type and have the same configuration. The suspension 8 mainly includes various arms and links such as an electromagnetic variable absorber 8a, a spring 8b, and a lower arm 8c. In each suspension 8, the damping force of the suspension can be changed by the electromagnetic variable absorber 8a, and the characteristics of the suspension can be changed. In the present embodiment, the electromagnetic variable absorber 8a corresponds to the suspension characteristic changing means described in the claims.

  The electromagnetic variable absorber 8a is a hydraulic absorber, and changes the damping force by changing the diameter of an orifice (oil passage) provided in the piston. The electromagnetic variable absorber 8a includes an actuator 8d, and changes the diameter of the orifice by driving the actuator 8d. In the electromagnetic variable absorber 8a, the damping force is increased by reducing the diameter of the orifice, and the damping force is decreased by increasing the diameter of the orifice. In the electromagnetic variable absorber 8a, when receiving the damping force control signal from the ECU 9, the actuator 8d is driven in accordance with the damping force control signal to change the diameter of the orifice.

  The ECU 9 is an electronic control unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], a motor drive circuit, and the like. In the ECU 9, various sensors such as the steering angle sensor 2 are connected, and detection signals from the various sensors are taken in every certain time. Then, the ECU 9 performs control such as vehicle turning control, high-speed traveling control, road surface condition control, loading condition control, motor drive control, suspension damping force control and the like based on each detection signal, and controls the wheels 7A, 7B, 7C, 7D. The motors 7v are controlled and the actuators 8d of the suspensions 8A, 8B, 8C, 8D are controlled. In the present embodiment, each process in the ECU 9 corresponds to a radius setting unit and a turning amount setting unit described in the claims.

  The vehicle turning control will be described. As shown in FIG. 4, when a truncated cone (for example, a paper cup) is tilted and rolled, it turns to the smaller diameter side due to the difference between the left and right diameters. In vehicle turning control, using this principle, the diameter of the inner turning wheel is made smaller than the diameter of the turning outer wheel in accordance with the steering direction of the operation angle, and the difference in diameter between the left and right wheels increases as the steering angle increases. Perform such control.

  Specifically, the ECU 9 determines whether the vehicle travels straight (the steering angle is 0 or almost 0) or turns based on the steering angle indicated by the steering angle signal. When it is determined that the vehicle is going straight, the ECU 9 sets a rim width in which all the wheels 7A, 7B, 7C, and 7D have the same radius, and the rim width of all the wheels 7A, 7B, 7C, and 7D The motor torque of each motor 7v is set. When going straight, a relatively large wheel radius is usually set (a relatively narrow rim width is set) as shown by the solid line in FIG. This wheel radius is a reference when traveling, and the turning outer wheel becomes this wheel radius when turning. It should be noted that the wheel radius when traveling straight is obtained in advance by the vehicle speed or the like and is set from a map or the like held in the ECU 9.

  When it is determined that the vehicle is turning, the ECU 9 determines the turning direction from the steering angle indicated by the steering angle signal, and sets the radii of the front and rear wheels 7 and 7 that become the turning inner wheel according to the magnitude of the steering angle. Then, the ECU 9 sets the rim width as the set radius, and sets the motor torque of each motor 7v such that the rim width of the wheels 7 and 7 as the turning inner wheel becomes the set rim width. When turning, the rim width of the turning outer wheel is fixed to the rim width when going straight. Further, the radius of the front and rear wheels 7 and 7 serving as turning inner wheels is set to a smaller value as the steering angle is larger. Note that the radius of the turning inner wheel at the time of turning is obtained in advance according to the rim width and the steering angle at the time of going straight, and is set from a map or the like held in the ECU 9.

  When turning by making the diameter of the turning inner wheel smaller than the diameter of the turning outer wheel, the vehicle body becomes an ideal roll that tilts inward as shown in FIG. 5, and the vehicle is stabilized. Further, since the tire is not steered during turning, no slip angle is generated. Therefore, the cornering resistance is 0 or almost 0 on the tire ground contact surface.

  High-speed traveling control will be described. It is desirable to improve the high-speed running performance by reducing the center of gravity of the vehicle during high-speed running and reducing air resistance. Therefore, in high-speed traveling control, the diameters of all the wheels 7A, 7B, 7C, and 7D are reduced and the vehicle height is decreased during high-speed traveling. Therefore, when traveling at high speed, the wheel radius (flatness) is reduced from a relatively large wheel radius during normal straight traveling. Specifically, the ECU 9 determines whether or not the vehicle is traveling at high speed based on the vehicle speed indicated by the vehicle speed signal. If it is determined that the vehicle is traveling at high speed, the radii of all the wheels 7A, 7B, 7C, and 7D are determined according to the vehicle speed. Set. Then, the ECU 9 sets the rim width that is the set radius, and sets the motor torque of each motor 7v such that the rim width of all the wheels 7A, 7B, 7C, and 7D becomes the set rim width. During high speed running, the radius of the wheels 7A, 7B, 7C, 7D is set to a smaller value as the vehicle speed increases. The wheel radius corresponding to the vehicle speed is obtained in advance and is set from a map or the like held in the ECU 9.

  The road surface condition control will be described. Since the riding comfort deteriorates on a road surface with many irregularities, it is desirable to improve the riding comfort. On the contrary, since the riding comfort does not deteriorate on a flat road surface, it is desirable to improve the steering stability and the power. Therefore, in the road surface condition control, the diameter of all the wheels 7A, 7B, 7C, 7D is increased on the road surface with many irregularities, the flatness of the tire is increased, and on the road surface with few irregularities, all the wheels 7A, 7B, 7C, The diameter of 7D is reduced, and the flatness of the tire is reduced. Specifically, the ECU 9 determines whether or not the difference in stroke between the four wheels is greater than or equal to a threshold value from the stroke indicated by the stroke signal of each wheel. judge. When it is determined that the road surface has a lot of unevenness, the ECU 9 sets the flatness according to the stroke difference, and sets the radii of all the wheels 7A, 7B, 7C, and 7D to be the set flatness. Then, the ECU 9 sets the rim width that is the set radius, and sets the motor torque of each motor 7v such that the rim width of all the wheels 7A, 7B, 7C, and 7D becomes the set rim width. When the stroke difference is less than the threshold value, the road surface is less uneven, and is fixed to a relatively large wheel radius (flatness) when traveling straight. The flatness ratio is obtained in advance according to a difference in stroke between wheels, and is set from a map or the like held in the ECU 9.

  The loading status control will be described. When a person is sitting or not sitting in each seat, the vehicle posture changes, and the vicinity of the sitting position sinks slightly. Therefore, in the loading status control, the vehicle radius is adjusted by increasing the radius of the wheel corresponding to the position sitting on the seat by a certain amount. Specifically, the ECU 9 determines the wheel corresponding to the seat on which the person is sitting from the seating information indicated by the seating signal corresponding to each seat, and sets the determined wheel radius to a radius that is increased by a certain amount. . Then, the ECU 9 sets a rim width that is a radius set for the determined wheel, and sets a motor torque of each motor 7v such that the determined rim width of the wheel becomes the set rim width.

  The motor drive control will be described. When the motor torque of each motor 7v is set, the ECU 9 sets a target current necessary for generating the set motor torque by each motor 7v. Then, the ECU 9 supplies current to each motor 7v from the motor drive circuit so that the target current is obtained. At this time, the motor current or the like actually flowing through the motor 7v may be detected, and feedback control may be performed so that the set target current is obtained.

  The suspension damping force control will be described. When the rim width is changed in each control as described above, the center position in the vehicle width direction of the wheel that has changed the rim width changes, so the tread of the vehicle changes. Therefore, the load input to the suspension (particularly, the suspension of the wheel whose rim width is changed) changes. Incidentally, in each suspension 8, a damping force corresponding to the load is set assuming a load input to the suspension when traveling straight (during a reference tread).

  The change in the load input to the suspension will be specifically described by taking as an example the case where the rim width of the turning inner wheel is widened by vehicle turning control. For example, as shown in FIG. 2, when the rim width of the right front wheel (turning inner wheel) 7A is widened, the center position of the right front wheel 7A moves outward in the vehicle width direction, and the center position and the upper end of the suspension 8A. The distance in the vehicle width direction between the attachment position with the vehicle body BD increases from L1 to L2. Therefore, the bending moment acting on the suspension 8A changes, and the bending moment increase ΔM = (L2−L1) × W obtained by multiplying the distance change (L2−L1) by the tire wheel load W is the suspension 8A (electromagnetic variable). Acting in the axial direction of the type absorber 8a). The tire wheel load is a value determined by the vehicle and is a constant value.

  The electromagnetic variable absorber 8a contracts due to this bending moment increase ΔM. That is, since the load input in the axial direction of the electromagnetic variable absorber 8a increases, the axial force in the direction in which the electromagnetic variable absorber 8a is contracted increases, and the apparent damping force of the electromagnetic variable absorber 8a decreases. As a result, the vehicle posture may change, or the behavior (transient characteristics) during turning may be reduced. Therefore, by increasing the damping force of the electromagnetic variable absorber 8a by this damping force decrease (bending moment increase ΔM), a stable vehicle posture is maintained and a decrease in behavior during turning is suppressed.

  Conversely, when the rim width of the wheel is narrowed, the center position of the wheel moves inward in the vehicle width direction, so the distance in the vehicle width direction between the center position and the mounting position of the suspension 8 is short. Become. Therefore, since the above-described bending moment is reduced, the apparent damping force of the electromagnetic variable absorber 8a is increased, so that the damping force of the electromagnetic variable absorber 8a is decreased by this damping force increase (bending moment reduction).

  Specifically, the ECU 9 determines, for each wheel, between the center position of the wheel 7 and the mounting position of the vehicle body BD at the upper end of the suspension 8 based on the stroke indicated by the connecting shaft stroke sensor 6. The distance L in the vehicle width direction is calculated. In the ECU 9, for each wheel, the calculated distance L is a distance in the vehicle width direction between the center position of the wheel 7 when traveling straight (during the reference tread) and the mounting position of the vehicle body BD at the upper end of the suspension 8. It is determined whether or not it has changed from Lb. The ECU 9 determines that the rim width (tread) of the wheel 7 has changed when the distance L has changed from the distance Lb. When it is determined that the radius of the wheel 7 needs to be changed in each control of the vehicle turning control, the high speed traveling control, the road surface condition control, and the loading condition control, the rim width of the wheel 7 is changed. In addition, by obtaining such a determination result from each control of the high-speed traveling control, the road surface condition control, and the loading condition control, the determination by comparing the distance L and the distance Lb may not be performed.

  When it is determined that the wheel rim width has changed, the ECU 9 determines the apparent damping force change ΔG = k × (L−Lb) of the electromagnetic variable absorber 8a based on the distance change (L−Lb). Is calculated. Then, the ECU 9 sets a damping force control signal for changing the damping force based on the damping force change ΔG, and transmits the damping force control signal to the actuator 8d of the corresponding electromagnetic variable absorber 8a. When the rim width (tread) is wide (when L> Lb), the damping force change ΔG becomes a positive value, and a damping force control signal for increasing the damping force is set. On the other hand, when the rim width (tread) becomes narrower (when L <Lb), the damping force change ΔG becomes a negative value, and a damping force control signal for reducing the damping force is set. Note that k is a change coefficient of ΔG, and is set in advance based on the suspension arrangement, type, spring constant, damping force during straight travel (during reference tread), and the like.

  When it is determined that the rim widths of all the wheels have not changed (that is, when all the rim widths are the reference rim widths), the above-described high-speed traveling control, road surface state control, and loading state control are electromagnetically variable. You may make it carry out by damping force control of the absorber 8a. Alternatively, instead of changing the wheel rim width (ie, wheel diameter) to perform high-speed traveling control, road surface condition control, and loading condition control, these controls are always performed by damping force control of the electromagnetic variable absorber 8a. It may be.

  With reference to FIGS. 1-3, operation | movement of the behavior control apparatus 1 is demonstrated. Here, the operation in the behavior control apparatus 1 when the vehicle turns right from the straight line according to the steering operation of the driver will be described.

  When traveling straight, the behavior control apparatus 1 sets a relatively large radius for all the wheels 7A, 7B, 7C, and 7D, and adjusts the rim width that is necessary to achieve the set radius. Therefore, in the vehicle, the right wheels 7A and 7C and the left wheels 7B and 7D have the same relatively large radius, and the right front wheel 7C and the left rear wheel 7D are connected to each other by the connecting shaft 7m. Rotate at the same rotational speed and go straight. At this time, the driver operates the steering wheel clockwise. Then, the steering angle of the steering wheel changes from zero. The steering angle sensor 2 detects the steering angle of the steering wheel, and transmits the detected value to the ECU 9 as a steering angle signal. The magnitude of the detected steering angle increases from 0 and changes according to the operation amount of the steering wheel.

  The ECU 9 receives the steering angle signal from the steering angle sensor 2 at regular intervals, and determines the steering direction as the right direction from the steering angle. Then, the ECU 9 determines the turning inner wheels as the right wheels 7A and 7C and the turning outer wheels as the left wheels 7B and 7D from the right steering direction, and sets the radius of the turning inner wheels 7A and 7C according to the magnitude of the steering angle. Then, the ECU 9 sets the rim width according to the set radius, and sets the motor torque necessary for achieving the set rim width. Further, the ECU 9 sets a target current necessary for generating the set motor torque in each motor 7v, and supplies current to each motor 7v of the turning inner rings 7A and 7C from the motor drive circuit so as to obtain the target current. To do. At this time, no current is supplied to the motors 7v of the outer turning wheels 7B and 7D.

  The motors 7v in the turning inner rings 7A and 7C generate motor torque corresponding to the supplied current and are driven to rotate. The rotation of the motor 7v is transmitted to the pinion 7t via the speed reduction mechanism 7w, and rotates the pinion 7t. The rotation of the pinion 7t is transmitted to the rack 7s, and moves the rack 7s to the outside in the vehicle width direction. As the rack 7s moves, the bearing 7r also moves outward in the vehicle width direction. As the bearing 7r moves, the outer connecting shaft 7i and the outer drive shaft move outward in the vehicle width direction, and the axial lengths of the outer connecting shaft 7i and the outer drive shaft become longer. Changes in the axial lengths of the outer connecting shaft 7i and the outer drive shaft are absorbed by the constant velocity joint 7o. By the movement of the outer connecting shaft 7i and the outer drive shaft, the outer wheel 7e slides outward in the vehicle width direction with respect to the inner wheel 7d.

  Due to the sliding movement of the outer wheel 7e, the rim width of each wheel 7a of the turning inner wheels 7A, 7C becomes wider than that during straight travel, and the radius of the turning inner wheels 7A, 7C becomes smaller. The radius of the turning inner wheels 7A and 7C decreases as the steering angle increases. At this time, the radii of the turning outer wheels 7B and 7D are fixed to the radii when traveling straight.

  Since the radius of the turning inner wheels 7A and 7C becomes smaller than that during straight travel, a difference occurs between the radius of the turning inner wheels 7A and 7C and the radius of the turning outer wheels 7B and 7D. Further, the right wheel 7A and the left wheel 7B are rotated at the same rotational speed by the connecting shaft 7m, and the right wheel 7C and the left wheel 7D are rotated at the same rotational speed by the drive shaft. Therefore, the vehicle turns in the direction of the turning inner wheels 7A and 7C due to the difference in radius between the left and right wheels and the rotation at the same speed. At this time, the turning radius decreases as the difference between the left and right wheel radii increases.

  At this time, since the rim width is wide on the turning inner wheels 7A and 7C, the distance in the vehicle width direction between the center position of the turning inner wheels 7A and 7C and the mounting position of the suspension 8A and the upper end of the suspension 8A and 8C on the vehicle body BD. Becomes longer. The connecting shaft stroke sensor 6 detects the stroke amount of the connecting shaft 7m, and transmits the detected value to the ECU 9 as a connecting shaft stroke signal. The detected stroke amount is greater for the turning inner wheels 7A and 7C than when the vehicle is traveling straight.

  The ECU 9 receives a connecting shaft stroke signal from the connecting shaft stroke sensor 6 at regular intervals, and based on the connecting shaft stroke signal, the vehicle body BD at the center position of each wheel 7 and the upper end of each suspension 8. The distance L in the vehicle width direction between each and the attachment position is calculated. Then, the ECU 9 determines, for each wheel, whether or not the calculated distance L has changed from the straight distance Lb. At this time, the ECU 9 determines that the distance L has increased from the distance Lb for the turning inner wheels 7A and 7C.

  The ECU 9 calculates an apparent damping force decrease ΔG = k × (L−Lb) of the electromagnetic variable absorber 8a based on the distance increase (L−Lb) for the turning inner wheels 7A and 7C. Then, the ECU 9 sets a damping force control signal for increasing the damping force decrease ΔG, and transmits the damping force control signal to the actuator 8d of the electromagnetic variable absorber 8a of the turning inner wheel suspensions 8A and 8C.

  In each electromagnetic variable absorber 8a in the turning inner wheel, the actuator 8d is driven based on the damping force control signal. By driving the actuator 8d, the diameter of the orifice is reduced and the damping force of the electromagnetic variable absorber 8a is increased. The increase in the damping force is an amount corresponding to an increase in load (a bending moment increase ΔM) input to the suspensions 8A and 8C according to an increase in the tread on the turning inner wheel side. Due to the increase of the damping force of the electromagnetic variable absorber 8a, the apparent damping force of the electromagnetic variable absorber 8a becomes approximately the same as the damping force during straight travel, and the axial contraction of the electromagnetic variable absorber 8a is suppressed. . As a result, the tread of the vehicle is widened at the time of turning, but the vehicle posture can be turned stably and the riding comfort is not lowered.

  According to this behavior control device 1, the rim width of the wheel 7a can be arbitrarily changed by a simple configuration in which the outer wheel 7e is slid with respect to the inner wheel 7d. Accordingly, the height (flatness) of the tire 7b can be arbitrarily changed, the diameter of the wheel 7 can be changed, and various behavior controls can be performed. Furthermore, according to the behavior control device 1, even when the rim width of the wheel 7a is changed (even when the tread of the vehicle is changed), the suspension characteristics are controlled in accordance with the change in the tread, thereby A decrease in ride comfort and steering stability can be suppressed.

  In particular, the behavior control apparatus 1 can control the suspension characteristics with high accuracy by adjusting the damping force characteristics by the electromagnetic variable absorber 8a. Further, the behavior control device 1 can perform vehicle height control such as high-speed traveling control, road surface condition control, and loading condition control by rim width control of the wheel 7a and damping force control of the electromagnetic variable absorber 8a. Riding comfort and handling stability can be improved. Further, in the behavior control device 1, by providing a difference between the radius of the turning inner wheel and the radius of the turning outer wheel, the vehicle can be turned without turning the wheel.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the configuration is applied to a vehicle driven by a rear wheel by an engine, but may be applied to a vehicle driven by an in-wheel motor, may be applied to a vehicle driven by a motor, or The present invention may be applied to a front-wheel drive or four-wheel drive vehicle. If the wheel rotation can be controlled individually as in the in-wheel motor type, the left and right wheels can be controlled to the same rotation speed, so a mechanism for rotating the left and right wheels at the same rotation speed as in this embodiment is required. And not.

  In this embodiment, the present invention is applied to a vehicle with a MacPherson strut type suspension, but other suspension type vehicles such as a double wishbone type can also be applied.

  In this embodiment, the shaft delivery mechanism is provided in the wheel. However, the slide mechanism drive unit may be arranged on the outer peripheral side or the inner peripheral side of the sliding portion between the outwheel and the inner wheel. .

  In the present embodiment, the present invention is applied to a suspension having an electromagnetic variable absorber to change the damping force characteristic of the suspension. However, other means can be used as means for changing the suspension characteristics (spring characteristics, damping force characteristics, etc.). For example, there is an air suspension. In the case of a suspension that changes the spring characteristics, the strength of the spring is controlled according to the change in the rim width.

  In the present embodiment, the suspension damping force is increased when the wheel rim width is widened (when the tread is long). However, depending on the characteristics of the vehicle, the suspension may be increased when the wheel rim width is widened. There is also a pattern that reduces the damping force.

  Further, in this embodiment, the suspension damping force in the wheel on the side where the rim width is changed is changed. However, in consideration of the balance of the entire vehicle, the suspension is attenuated in the wheel on the side where the rim width is not changed. It is good also as a structure which also changes force.

  In this embodiment, in addition to turning control by changing the wheel radius, it is applied to a behavior control device that performs high-speed traveling control, road surface state control, and loading state control, but it is applied to a turning device that performs only turning. Alternatively, it may be applied to a device that performs only high-speed traveling control, road surface condition control, and loading condition control, or in addition to these, vehicle behavior based on yaw rate, lateral acceleration, suspension stroke, etc. And may be applied to control that stabilizes the behavior.

  In the present embodiment, the present invention is applied to the case where the vehicle is turned according to the driver's steering operation. However, when the vehicle is turned by lane keeping, the turning amount of the vehicle is controlled in order to stabilize the behavior of the vehicle. The present invention is also applicable to a case where the vehicle is turned by automatic steering. Alternatively, control suitable for each driving method may be performed. For example, in the case of a rear-wheel drive vehicle, when a large driving force is generated, the rear wheel diameter is controlled to be larger than the front wheel diameter in order to obtain a front-turned vehicle posture that is aerodynamically advantageous. Adjust the vehicle attitude in the pitching direction.

  In the present embodiment, the change in the rim width (tread) is detected by the connecting shaft stroke sensor. However, other means may be used as a means for detecting the change in the rim width, for example, an inner wheel and an outer wheel. There are means for detecting a change in the slide portion (that is, the rim width) and means for detecting a change in the diameter of the wheel and obtaining a change in the rim width from the change in the diameter.

  Further, in the present embodiment, the outer wheel is slid with respect to the inner wheel. However, the inner wheel and the outer wheel may be slid, or the inner wheel may be slid. In the case of a configuration in which the inner wheel is slid, the effect of suppressing the roll can be obtained by sliding the inner wheel outward and enlarging the tread between the left and right wheels.

  Further, in the present embodiment, an inner wheel and an out wheel are provided, and the rim width is variable by sliding the outer wheel with respect to the inner wheel. However, the rim width is variable by another mechanism. It is good.

  In the present embodiment, the tire is provided with a tube. However, the tube may be omitted if sufficient airtightness is ensured in the sliding portion between the inner wheel and the outer wheel.

  Further, in the present embodiment, the reinforcing material is provided at a plurality of locations in the tire, but the reinforcing material may not be provided when the tire has sufficient resistance to deformation.

It is a block diagram of the behavior control apparatus which concerns on this Embodiment. It is a partially broken front view of the wheel (front wheel side) of the behavior control device according to the present embodiment. It is a front sectional view of the shaft delivery mechanism on the right wheel side according to the present embodiment. It is a principle figure of the turning by the radius difference on either side concerning this embodiment. It is a mimetic diagram at the time of seeing the vehicles at the time of vehicles turning concerning this embodiment from back.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Behavior control apparatus, 2 ... Steering angle sensor, 3 ... Vehicle speed sensor, 4 ... Suspension stroke sensor, 5 ... Seating sensor, 6 ... Stroke sensor for connecting shaft, 7 ... Wheel, 7A ... Right front wheel, 7B ... Left front wheel 7C ... Right rear wheel, 7D ... Left rear wheel, 7a ... Wheel, 7b ... Tire, 7c ... Shaft feed mechanism, 7d ... Inner wheel, 7e ... Outer wheel, 7f ... Reinforcement material, 7g ... Tube, 7i ... Outside Connecting shaft, 7j ... nut, 7k ... outer periphery, 7l ... bearing, 7m ... connecting shaft, 7n ... central connecting shaft, 7o ... constant velocity joint, 7q ... case, 7r ... bearing, 7s ... rack, 7t ... pinion, 7u ... Actuator, 7v ... Motor, 7w ... Deceleration mechanism, 8 ... Suspension, 8A ... Right front suspension, 8B ... Left front suspension, 8C ... Right rear suspension, 8D ... Left rear suspension Emissions, 8a ... variable solenoid absorber, 8b ... spring, 8c ... lower arm, 8d ... actuator

Claims (5)

Radius setting means for setting the radius of the left and right wheels;
Radius changing means for changing the radius of the wheel according to the rim width of the wheel;
Suspension characteristic changing means for changing the characteristics of the suspension,
When the radius of the left wheel or / and the right wheel is changed by the radius changing means according to the radius set by the radius setting means, the suspension characteristic changing means according to the change in the rim width of the wheel by the radius changing means. A vehicle behavior control device characterized by changing a characteristic of a suspension.   2. The vehicle behavior control device according to claim 1, wherein the suspension characteristic changing unit changes a damping force characteristic of the suspension.   The vehicle behavior control device according to claim 1, wherein the suspension characteristic changing unit changes a spring characteristic of the suspension. A turning amount setting means for setting a turning amount of the vehicle;
The radius setting means increases the radius of the outer turning wheel with respect to the radius of the inner turning wheel as the turning amount set by the turning amount setting means is larger. A vehicle behavior control device to be described. The radius changing means is
A wheel composed of an inner wheel arranged on the inner side in the vehicle width direction and an outer wheel arranged on the outer side,
Pneumatic tires respectively coupled to the rim of the inner wheel and the rim of the outer wheel;
The vehicle behavior control device according to claim 1, further comprising: an actuator that slides at least one of the inner wheel and the outer wheel in a vehicle width direction.

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