JP2009202621A - Stabilizer system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly practicable stabilizer system for a vehicle. <P>SOLUTION: In a system, a pair of stabilizer devices capable of changing respective roll suppressing forces by the operations of respective actuators are so installed as to correspond to front and rear wheels. The system changes the distribution ratio of the roll suppressing forces to be generated by the pair of stabilizer devices according to a pitch moment index quantity (longitudinal acceleration: Gzg). Since a load movement occurs in the longitudinal direction of the vehicle when the vehicle is accelerated or decelerated during the turning of the vehicle, the cornering powers of the front and rear wheels are changed, and the steering characteristics (stability factor: k) of the vehicle are changed (solid line). The distribution ratio and the steering characteristics are closely related to each other. Therefore, the steering characteristics of the vehicle can be changed by changing the distribution ratio. By the system, the steering characteristics of the vehicle during the acceleration and deceleration can be adjusted (dotted line, chain line). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stabilizer system mounted on a vehicle, and more particularly, to a stabilizer system including a stabilizer device that can change a roll restraining force generated by itself by operation of an actuator.

The vehicle stabilizer system is a system that suppresses the roll of the vehicle body using the torsional reaction force of the stabilizer bar. In recent years, as described in the following patent document, a system including an actuator and capable of changing the roll restraining force, for example, actively by the actuator has been studied, and has already been put into practical use.
JP 2006-321296 A Japanese Patent Publication No. 7-17135

  In a stabilizer system in which the roll restraining force generated by the stabilizer bar can be changed by the operation of the actuator, the roll restraining force is changed to a magnitude corresponding to the roll moment received by the vehicle body due to the turning of the vehicle. Can be suppressed. Such a system has just begun to be put into practical use, leaving much room for improvement of the control method. Therefore, it is possible to improve the practicality of the stabilizer system by making various improvements. This invention is made | formed in view of such a situation, and makes it a subject to provide a highly practical vehicle stabilizer system.

  In order to solve the above-described problems, a vehicle stabilizer system according to the present invention is a system in which a pair of stabilizer devices capable of changing a roll suppression force by operation of an actuator is provided corresponding to front and rear wheels. Pitch moment index that indicates the ratio of the front wheel side roll restraining force and the rear wheel side roll restraining force that should be generated by each of the stabilizer devices to the pitch moment that the vehicle body receives due to acceleration / deceleration of the vehicle Configured to change based on quantity.

  When the vehicle accelerates or decelerates when the vehicle turns, the load movement occurs in the front-rear direction of the vehicle, so that the cornering power generated in each of the front and rear wheels changes and the understeer tendency becomes stronger or weaker. In other words, the steering characteristics of the vehicle change as the vehicle accelerates / decelerates. Further, the roll rigidity distribution of the front and rear wheels and the steering characteristics of the vehicle are closely related, and the steering characteristics of the vehicle can be changed by changing the roll rigidity distribution, as will be described in detail later. . Since the stabilizer system of the present invention can change the roll stiffness distribution based on the pitch moment index amount, the steering characteristic can be changed based on the pitch moment index amount. Therefore, according to the system of the present invention, for example, it is possible to adjust the steering characteristics during acceleration / deceleration of the vehicle, and it is possible to improve the practicality of the system.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. In the following items, items (1) to (8) correspond to claims 1 to 8, respectively.

(1) Provided corresponding to the front and rear wheels, each of which has a stabilizer bar and an actuator, generates a roll restraining force depending on the torsional reaction force of the stabilizer bar, and A front wheel side stabilizer device and a rear wheel side stabilizer device that can be changed by an actuator, and
(a) The total roll restraining force to be generated by each of the front wheel side stabilizer device and the rear wheel side stabilizer device is determined based on the roll moment index amount indicating the roll moment received by the vehicle body due to the turning of the vehicle. A roll restraining force determining unit that performs (b) the roll restraining force determined by the roll restraining force determining unit based on the roll restraining force distribution ratio and the roll restraining force that the front wheel side stabilizer device should generate. A roll restraining force distribution portion that distributes to a certain front wheel side roll restraining force and a rear wheel side roll restraining force that is a roll restraining force that should be generated by the rear wheel side stabilizer device, and is distributed by the roll restraining force distributing portion. Based on each of the front wheel side roll restraining force and the rear wheel side roll restraining force, the front wheel side stabilizer device and the rear wheel side star A vehicle stabilizer system equipped with a control device for controlling the operation of the actuator, each having a riser system,
The vehicle stabilizer system configured such that the roll restraining force distribution unit changes the roll restraining force distribution ratio based on a pitch moment index amount that indexes a pitch moment received by a vehicle body due to acceleration / deceleration of the vehicle. .

  When the vehicle turns, if a pitch moment is generated in the vehicle body due to the acceleration / deceleration of the vehicle, the load movement occurs in the longitudinal direction of the vehicle, and the cornering power generated in each of the front and rear wheels changes, and the understeer tendency is strong. Become weak or weak. Specifically, when the vehicle accelerates, the load on the rear wheel increases, so that the cornering power generated on the rear wheel increases and the understeer tendency increases, while when the vehicle decelerates, the load on the front wheel side increases. By increasing, the cornering power generated in the front wheels increases and the understeer tendency becomes weaker. That is, during acceleration / deceleration of the vehicle, the steering characteristics of the vehicle change as shown by the solid line in FIG. Here, the stability factor k on the vertical axis indicates the steering characteristic of the vehicle, and more specifically indicates the degree of the understeer tendency or the oversteer tendency. The stability factor k indicates that the understeer tendency is strong as the value thereof is large, and the understeer tendency is weak as the value thereof is small. In other words, the larger the value, the weaker the oversteer tendency, and the smaller the value, the stronger the oversteer tendency. Further, when the value of the longitudinal acceleration Gzg is positive, the vehicle is accelerating, and when the value of the longitudinal acceleration Gzg is negative, it means that the vehicle is decelerating.

  Further, as will be described in detail later, the cornering power of the wheels and the roll rigidity distribution of the front and rear wheels are closely related to each other. The higher the roll rigidity of the front wheels, the lower the cornering power of the front wheels. The cornering power of the rear wheel decreases as the roll rigidity of the wheel increases. That is, the higher the roll rigidity of the front wheel, the stronger the understeer tendency, while the higher the rear wheel roll rigidity, the weaker the understeer tendency. In the vehicle stabilizer system according to this aspect, the roll restraining force distribution ratio, that is, the roll rigidity distribution can be changed based on the pitch moment index amount. It is possible to change based on the index amount. Therefore, according to the system of the aspect described in this section, it is possible to change the degree of change in the steering characteristics accompanying the acceleration / deceleration of the vehicle, in other words, the slope of the straight line in FIG. It becomes possible to adjust the steering characteristics during deceleration. For example, as shown by the one-dot chain line in FIG. 1, it becomes possible to prevent the steering characteristics of the vehicle from changing depending on the degree of acceleration / deceleration of the vehicle. Specifically, for example, the roll restraining force distribution ratio is changed so that the roll rigidity of the rear wheels becomes higher in order to weaken the understeer tendency as the vehicle accelerates, while the understeer tendency becomes stronger as the vehicle decelerates. Therefore, by changing the roll restraining force distribution ratio so that the roll rigidity of the front wheels is increased, the steering characteristics can be kept constant regardless of the degree of acceleration / deceleration of the vehicle. Further, as will be described in detail later, as indicated by a dotted line in FIG. 1, it is possible to increase the degree of change in steering characteristics accompanying acceleration / deceleration of the vehicle. Specifically, for example, the roll restraining force distribution ratio is changed so that the roll rigidity of the front wheels becomes higher to increase the understeer tendency as the vehicle accelerates. On the other hand, the understeer tendency is weakened as the vehicle decelerates. By changing the roll restraining force distribution ratio so that the roll rigidity of the rear wheels is increased, it becomes possible to greatly change the steering characteristics with the acceleration / deceleration of the vehicle.

  The “roll restraining force distribution ratio” described in this section means the roll rigidity distribution of the front and rear wheels, and may be the ratio of the front wheel side roll restraining force and the rear wheel side roll restraining force, The front wheel side roll restraining force and the ratio of the rear wheel side roll restraining force to the roll restraining force obtained by summing the front wheel side roll restraining force and the rear wheel side roll restraining force may be used.

  The “roll moment index amount” described in this section is a parameter that directly or indirectly represents the magnitude of the roll moment received by the vehicle body due to the turning of the vehicle. It is a variety of physical quantities that can represent whether it is received. Specifically, the roll moment index amount includes various things such as the steering angle of the vehicle, the vehicle traveling speed, the lateral acceleration generated in the vehicle body, and the yaw rate of the vehicle, including the roll moment itself. The “pitch moment index amount” described in this section is a parameter that directly or indirectly represents the magnitude of the pitch moment received by the vehicle body due to vehicle acceleration / deceleration. These are various physical quantities that can indicate whether the vehicle body receives. Specifically, the pitch moment itself includes various things such as the accelerator slot opening, the brake pressure, and the longitudinal acceleration generated in the vehicle body, for example.

  The configuration of the “stabilizer device” described in this section is not particularly limited. For example, as will be described later, the stabilizer bar is divided into two at the center and is constituted by a pair of stabilizer bar members, and an actuator is disposed between the pair of stabilizer bar members. However, the configuration may be such that the pair of stabilizer bar members are rotated relative to each other to twist the stabilizer bar. Further, for example, an actuator is disposed between one end of the stabilizer bar and a member that holds the wheel, and the actuator changes the interval between the one end and the member that holds the wheel, thereby stabilizing the stabilizer. It may be configured to twist the bar.

  (2) In the case where the roll suppression force distribution unit is a value that indicates the pitch moment that the vehicle body receives due to acceleration of the vehicle, the amount of pitch moment is not as such. The vehicle stabilizer system according to (1), wherein the roll restraining force distribution ratio is changed so that the ratio of the front wheel side roll restraining force is increased.

  (3) When the pitch moment index amount is a value indicating the pitch moment received by the vehicle body due to acceleration of the vehicle, the roll restraining force distribution unit increases the front wheel side roll as the pitch moment index amount increases. The vehicle stabilizer system according to (2), wherein the roll restraining force distribution ratio is changed so that the restraining force ratio increases.

  At the time of acceleration / deceleration of the vehicle, as described above, the cornering power of the front and rear wheels changes and the steering characteristics change. Further, the cornering power of the wheel and the roll rigidity are closely related, and as will be described in detail later, the cornering power of the wheel decreases as the roll rigidity is increased. For this reason, when the roll of the vehicle body is suppressed by the stabilizer device, that is, when the roll suppression control is executed, the roll rigidity is increased and the cornering power of the wheel is reduced as compared with the case where the roll suppression control is not executed. Therefore, for example, when roll suppression control is executed during acceleration turning of the vehicle, an increase in cornering power of the rear wheels due to vehicle acceleration is suppressed compared to a case where roll suppression control is not executed, and an understeering tendency Becomes weaker. On the other hand, when roll suppression control is executed during deceleration turning of the vehicle, an increase in the cornering power of the front wheels due to vehicle deceleration is suppressed and the understeer tendency becomes stronger than when roll suppression control is not executed. . That is, the degree of change in the steering characteristics accompanying the acceleration / deceleration of the vehicle is smaller when the roll suppression control is executed than when the roll suppression control is not executed. In other words, the slope of the straight line in FIG. 1 is smaller when roll suppression control is executed than when roll suppression control is not executed.

  As described above, when roll suppression control is executed during acceleration turning of the vehicle, the understeer tendency becomes weaker than when roll suppression control is not executed. There is a risk that it becomes difficult to suppress. In the system according to the aspect described in the above two items, it is possible to increase the understeer tendency during acceleration turning of the vehicle. Therefore, according to the system described in the above two items, for example, during acceleration turning of the vehicle When roll suppression control is executed, the understeer tendency can be strengthened in the same manner as when roll suppression control is not executed.

  (4) When the roll suppression force distribution unit is a value that indicates the pitch moment received by the vehicle body due to deceleration of the vehicle, the pitch moment index amount is not such a value, The vehicle stabilizer system according to any one of (1) to (3), wherein the roll restraining force distribution ratio is changed so that a ratio of the rear wheel roll restraining force is increased.

  (5) When the roll moment index amount is a value indicating the pitch moment received by the vehicle body due to deceleration of the vehicle, the roll restraining force distribution unit increases the pitch moment index amount as the rear wheel side increases. The vehicle stabilizer system according to (4), wherein the roll restraining force distribution ratio is changed so that a ratio of the roll restraining force is increased.

  In the system according to the aspect described in the above two items, it is possible to weaken the understeer tendency when the vehicle decelerates and turns. As described above, when the vehicle is decelerating and turning, when the roll suppression control is executed, the understeer tendency becomes stronger than when the roll suppression control is not executed. There is. Therefore, according to the system described in the above two items, for example, when roll suppression control is executed during deceleration turning of the vehicle, the understeer tendency can be weakened in the same manner as when roll suppression control is not executed. Thus, the turning ability of the vehicle can be improved.

(6) When an index indicating the degree of the understeer tendency or oversteer tendency that is the steering characteristic of the vehicle is defined as the steer characteristic index amount,
The roll restraining force distribution unit is configured to estimate the steering characteristic index amount based on the pitch moment index amount and to change the roll restraining force distribution ratio based on the estimated steer characteristic index amount. The vehicle stabilizer system according to (1).

  The steering characteristic of the vehicle can be estimated based on the cornering power of each wheel, and the cornering power of each wheel has a magnitude corresponding to the load applied to each wheel. Therefore, as the “steer characteristic index amount” described in this section, specifically, for example, the cornering power ratio of each wheel, each wheel, Such a load ratio or the like can be employed. When the stability factor is adopted as the steer characteristic index amount, the stability factor is estimated by estimating the load movement amount between the wheels accompanying acceleration / deceleration of the vehicle based on the pitch moment index amount, for example. It is possible to estimate based on the cornering power of each wheel in consideration of the load movement amount between them. Further, for example, the relationship between the pitch moment index amount and the stability factor is measured in advance, and the stability factor is directly estimated based on the pitch moment index amount without intentionally estimating the cornering power of each wheel. It is also possible.

  The “roll restraining force distribution ratio” described in this section is set in advance, for example, when the steer characteristic index amount is larger, the understeer tendency is stronger, and the smaller the steer tendency is weaker, the estimated steer characteristic index amount is preset. When the value is larger than the threshold value, the understeer tendency is increased compared to the case where the threshold value is less than or equal to the threshold value. It may be changed so that the understeer tendency becomes weaker in comparison. On the other hand, for example, when the estimated steer characteristic index amount is larger than the set threshold value, the understeer tendency is changed to be weaker than when the estimated steer characteristic index amount is less than or equal to the threshold value. In the case of being smaller, the understeer tendency may be changed so as to be stronger than the case where the threshold value is exceeded. Further, for example, in order to change the steering characteristic of the vehicle to the target steering characteristic, the vehicle may be changed according to the difference between the estimated steering characteristic index amount and the target steering characteristic index amount.

  (7) When the roll suppression force distribution unit is a value indicating that the estimated steer characteristic index amount has a stronger understeer tendency than the steer characteristic index amount when the vehicle body does not receive a pitch moment, The vehicle stabilizer system according to the item (6), wherein the roll restraining force distribution ratio is changed so that the ratio of the front wheel side roll restraining force is increased as compared with a case where such a value is not achieved. .

  In the system according to the aspect described in this section, the roll rigidity of the front wheels is increased when the estimated steering characteristic has a stronger understeer tendency than the steering characteristic when no pitch moment is generated in the vehicle body. That is, as can be seen from the solid line in FIG. 1, the system described in this section can increase the understeer tendency during accelerated turning of the vehicle. Therefore, according to the system described in this section, for example, when the roll suppression control is executed during acceleration turning of the vehicle, it is possible to increase the understeer tendency as in the case where the roll suppression control is not executed. .

  (8) When the roll suppression force distribution unit is a value indicating that the estimated steer characteristic index amount has a lower understeer tendency than the steer characteristic index amount when the vehicle body does not receive a pitch moment, Compared to the case where such a value does not occur, the roll restraining force distribution ratio is changed so that the ratio of the rear wheel side roll restraining force is increased. The vehicle stabilizer system as described.

  In the system according to the aspect described in this section, the roll rigidity of the rear wheel is increased when the estimated steering characteristic has a weaker understeer tendency than the steering characteristic when no pitch moment is generated in the vehicle body. That is, as can be seen from the solid line in FIG. 1, the system described in this section can reduce the understeer tendency when the vehicle turns at a reduced speed. Therefore, according to the system described in this section, for example, when roll suppression control is executed during deceleration turning of the vehicle, it is possible to weaken the understeer tendency as in the case where roll suppression control is not executed, It is possible to improve the turning performance of the vehicle.

(9) The stabilizer bar is
Provided corresponding to the left and right wheels, each of which extends in the vehicle width direction, and extends continuously across the torsion bar portion and intersects the torsion bar portion, and is suspended at the tip portion. Comprising a pair of stabilizer bar members having arm portions coupled to the arms,
The vehicle stabilizer system according to any one of (1) to (8), wherein the actuator relatively rotates a torsion bar portion of the pair of stabilizer bar members.

  In the system according to the aspect described in this section, there is a limitation on the specific structure of the stabilizer device, specifically, the configuration of the stabilizer bar and the actuator. According to the system of this aspect, the stabilizer force generated by the stabilizer device can be changed efficiently.

  (10) The actuator includes an electromagnetic motor as a drive source, a speed reducer that decelerates rotation of the electromagnetic motor, and a housing that holds the electromagnetic motor and the speed reducer, and the pair of stabilizer bars The vehicle according to item (9), wherein one torsion bar portion of the member is connected to the housing in a relatively non-rotatable manner, and the other torsion bar portion is connected to the output portion of the speed reducer in a relatively non-rotatable manner. Stabilizer system.

  In the system of the aspect described in this section, the structure of the actuator and the connection and arrangement relationship between the actuator and the stabilizer bar are specifically limited. In the aspect of this section, the mechanism of the speed reducer included in the actuator is not particularly limited. For example, it is possible to employ a reduction gear of various mechanisms such as a harmonic gear mechanism (sometimes referred to as “harmonic drive (registered trademark) mechanism”, “strain wave gearing mechanism”, etc.), a hypocycloid reduction mechanism, etc. . Considering the miniaturization of the electromagnetic motor, it is desirable that the reduction ratio of the reduction gear is relatively large (meaning that the operation amount of the actuator is small relative to the operation amount of the electromagnetic motor), and considering that point, the harmonic gear mechanism A speed reducer that employs is suitable for the system according to the aspect of this section.

  Hereinafter, embodiments and modifications of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention includes various aspects in which various modifications and improvements have been made based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. Can be implemented.

<Configuration of vehicle stabilizer system>
i) Overall Configuration of Vehicle Stabilizer System FIG. 2 schematically shows a vehicle stabilizer system 10 according to this embodiment. The stabilizer system 10 includes a pair of stabilizer devices 14 disposed on the front wheel side and the rear wheel side of the vehicle. Each of the stabilizer devices 14 includes a stabilizer bar 20 connected to a suspension arm (see FIGS. 3 and 4) that holds the left and right wheels 16 at both ends. The stabilizer bar 20 is configured to include a pair of stabilizer bar members 22 into which the stabilizer bar 20 is divided. The pair of stabilizer bar members 22 are connected by an actuator 26 so as to be relatively rotatable. It should be noted that the stabilizer device 14, the wheel 16, the stabilizer bar 20, the stabilizer bar member 22, the actuator 26, and the like are generic names, and when it is necessary to clarify which one of the front and rear wheels corresponds to the figure, As shown, F and R may be added to the front wheel and the rear wheel corresponding to the wheel position as a subscript.

ii) Configuration of Suspension Device A vehicle on which the system 10 is mounted is provided with four suspension devices corresponding to the wheels 16. The suspension device for the front wheel 16F, which is a steered wheel, and the suspension device for the rear wheel 16R, which is a non-steered wheel, can be regarded as having substantially the same configuration except for a mechanism that enables the wheels to be steered. The rear wheel suspension device will be described as a representative. As shown in FIGS. 3 and 4, the suspension device 30 is of an independent suspension type and is a multi-link type suspension device. The suspension device 30 includes a first upper arm 32, a second upper arm 34, a first lower arm 36, a second lower arm 38, and a toe control arm 40, each of which is a suspension arm. One end of each of the five arms 32, 34, 36, 38, 40 is rotatably connected to the vehicle body, and the other end is rotatable to an axle carrier 42 that rotatably holds the wheel 16. It is connected. With these five arms 32, 34, 36, 38, and 40, the axle carrier 42 can move up and down so as to draw a substantially constant locus with respect to the vehicle body. In addition, the suspension device 30 includes a coil spring 44 and a hydraulic shock absorber 46, which respectively include a mount portion 48 provided on a tire housing, which is a component of the spring upper portion, and a spring lower portion. They are arranged in parallel with each other between the second lower arm 38 as one component. That is, the suspension device 30 elastically supports the wheel 16 and the vehicle body, and generates a damping force against vibration accompanying the approach and separation.

iii) Structure of Stabilizer Device As shown in FIGS. 3 and 4, each stabilizer bar member 22 of the stabilizer device 14 is generally integrated with the torsion bar portion 50 extending in the vehicle width direction and intersects with the torsion bar portion 50. Thus, it can be divided into an arm portion 52 extending generally in front of the vehicle. The torsion bar portion 50 of each stabilizer bar member 22 is rotatably held by a holder 54 fixedly provided on the vehicle body at a location close to the arm portion 52 and is coaxially arranged. The end portions of the torsion bar portions 50 (end portions opposite to the arm portion 52 side) are connected to the actuators 26 as will be described in detail later. On the other hand, the end of each arm 52 (the end opposite to the torsion bar 50) is connected to the second lower arm 38 via a link rod 56. The second lower arm 38 is provided with a link rod connecting portion 58. One end of the link rod 56 is connected to the link rod connecting portion 58, and the other end is connected to the end of the arm portion 52 of the stabilizer bar member 22. It is linked so that it can move.

  As shown in FIG. 5, the actuator 26 included in the stabilizer device 14 is configured to include an electromagnetic motor 60 as a drive source and a speed reducer 62 that reduces and transmits the rotation of the electromagnetic motor 60. The electromagnetic motor 60 and the speed reducer 62 are provided in a housing 64 that is an outer shell member of the actuator 26. One end of the housing 64 is fixedly connected to the end of one torsion bar portion 50 of the pair of stabilizer bar members 22, while the other of the pair of stabilizer bar members 22 is connected to the housing 64. It is arranged in a state of extending from the other end portion of the motor to the inside thereof, and is connected to the speed reducer 62 as will be described in detail later. Further, the other of the pair of stabilizer bar members 22 is rotatably held by the housing 64 via the bush type bearing 70 at the axial intermediate portion thereof.

  The electromagnetic motor 60 includes a plurality of coils 72 fixed on a circumference along the inner surface of the peripheral wall of the housing 64, a hollow motor shaft 74 rotatably held in the housing 64, and the coil 72. And a permanent magnet 76 which is fixedly disposed on the outer periphery of the motor shaft 74. The electromagnetic motor 60 is a motor in which the coil 72 functions as a stator and the permanent magnet 76 functions as a rotor, and is a three-phase DC brushless motor. A motor rotation angle sensor 78 for detecting the rotation angle of the motor shaft 74, that is, the rotation angle of the electromagnetic motor 60 is provided in the housing 64. The motor rotation angle sensor 78 mainly includes an encoder and is used for controlling the actuator 26, that is, controlling the stabilizer device 14.

  The speed reducer 62 includes a wave generator 80, a flexible gear (flex spline) 82, and a ring gear (circular spline) 84. ”And so on). The wave generator 80 is configured to include an elliptical cam and a ball bearing fitted on the outer periphery thereof, and is fixed to one end of the motor shaft 74. The flexible gear 82 has a cup shape in which the peripheral wall portion can be elastically deformed, and a plurality of teeth (400 teeth in the speed reducer 62) are formed on the outer periphery on the opening side of the peripheral wall portion. The flexible gear 82 is connected to and supported by the end of the other torsion bar portion 50 of the pair of stabilizer bar members 22 described above. More specifically, the torsion bar portion 50 of the stabilizer bar member 22 passes through the motor shaft 74, and penetrates the bottom portion of the flexible gear 82 as the output portion of the speed reducer 62 on the outer peripheral surface of the portion extending from the motor shaft 74. In this state, it is connected to the bottom of the base plate by spline fitting so that relative rotation is impossible. The ring gear 84 is generally ring-shaped and has a plurality of teeth (402 teeth in the present speed reducer 62) formed on the inner periphery, and is fixed to the housing 64. The flexible gear 82 is fitted into the ring gear 84 at two locations located in the major axis direction of the ellipse, and is not meshed at other locations, with its peripheral wall portion being fitted on the wave generator 80 and elastically deformed into an elliptical shape. It is said that. With such a structure, when the wave generator 80 rotates once (360 degrees), that is, when the motor shaft 74 of the electromagnetic motor 60 rotates once, the flexible gear 82 and the ring gear 84 are relatively rotated by two teeth. . That is, the reduction ratio of the reduction gear 62 is 1/200.

  With the above configuration, a force that relatively changes the distance between one of the left and right wheels 16 and the vehicle body and the distance between the other of the left and right wheels 16 and the vehicle body, that is, a roll moment, acts on the vehicle body by turning the vehicle or the like. In this case, a force that relatively rotates the left and right stabilizer bar members 22, that is, an external force acting on the actuator 26 acts. In that case, the actuator 26 causes the external force to be generated by a motor force that is generated by the electromagnetic motor 60 (which may be referred to as rotational torque because the electromagnetic motor 60 is a rotational motor and may be considered rotational torque). When the force which opposes is generated, one stabilizer bar 20 constituted by these two stabilizer bar members 22 is twisted. The torsional reaction force generated by this twisting is a force that opposes the roll moment. That is, the stabilizer device 14 relies on the motor force to generate the torsional reaction force of the stabilizer bar 20 as a roll restraining force. Further, if the relative rotational position of the left and right stabilizer bar members 22 is changed by changing the rotational position of the actuator 26 (which is the operating position) by the motor force, the roll restraining force changes, and the vehicle body The roll can be actively suppressed. In the control of the system 10, the operation position of the actuator 26 is treated as an operation amount based on a predetermined neutral position. This neutral position is set, for example, as the operating position of the actuator 66 when the vehicle is stopped on a flat road.

iv) Configuration of Control Device In this stabilizer system 10, as shown in FIG. 2, an electronic control unit (ECU) 90 corresponding to two stabilizer devices 14 is provided. The ECU 90 is a control device that controls the operation of each stabilizer device 14, specifically, each actuator 26, and includes two inverters 92 as a drive circuit corresponding to the electromagnetic motor 60 included in each actuator 26, CPU, ROM, and RAM Etc., and a controller 96 mainly composed of a computer equipped with the above (see FIG. 10). Each of the inverters 92 is connected to the battery 100 via the converter 98 and is connected to the electromagnetic motor 60 of the corresponding stabilizer device 14. The electromagnetic motor 60 is driven at a constant voltage, and the amount of power supplied to the electromagnetic motor 60 is changed by changing the amount of supplied current. The supply current amount is changed by the inverter 92 changing the ratio (duty ratio) between the pulse on time and the pulse off time by PWM (Pulse Width Modulation).

  In addition to the motor rotation angle sensor 78, the controller 96 includes a steering sensor 102 for detecting an operation angle of the steering wheel, which is an operation amount of the steering operation member as a steering amount, and a lateral acceleration actually generated in the vehicle body. A lateral acceleration sensor 104 that detects a certain actual lateral acceleration and a longitudinal acceleration sensor 106 that detects longitudinal acceleration generated in the vehicle body are connected. The controller 96 is further connected to a brake electronic control unit (hereinafter also referred to as “brake ECU”) 108 which is a control device of the brake system. The brake ECU 108 is connected to a wheel speed sensor 110 that is provided for each of the four wheels and detects the rotational speed of each of the four wheels. Has a function of estimating the traveling speed of the vehicle (hereinafter sometimes referred to as “vehicle speed”). The controller 96 acquires the vehicle speed from the brake ECU 108 as necessary. Further, the controller 96 is also connected to each inverter 92 and controls them to control the electromagnetic motor 60 of each stabilizer device 14. Note that a ROM included in the computer of the controller 96 stores a program related to the control of each stabilizer device 14 to be described later, various data, and the like.

<Control of vehicle stabilizer system>
In the present system 10, roll suppression control is performed so that the actual rotational position that is the actual rotational position of the actuator 26 becomes the target rotational position that is the target rotational position in order to suppress the roll of the vehicle body. More specifically, the target rotational position of the actuator 26 is determined according to the roll moment received by the vehicle body in order to generate the roll restraining force according to the roll moment received by the vehicle body due to the turning of the vehicle, and the rotation of the actuator 26 is determined. The position is controlled to be the target rotational position. Since the rotational position of the actuator 26 has a corresponding relationship with the motor rotational angle that is the operating angle of the electromagnetic motor 60, in actual control, the motor rotational angle is treated as the rotational position of the actuator 26, and the motor rotational angle sensor 78 Control is performed based on the acquired motor rotation angle. That is, in the present system 10, the roll suppression force can be changed according to the operation amount of the electromagnetic motor 60.

Further, when the vehicle turns, a change in cornering power occurs due to load movement between the left and right wheels. This will be described in detail with reference to FIG. 6 showing the relationship between the cornering power CP and the load W applied to the wheel. When no load movement occurs between the left and right wheels, a load W ₀ is applied to each of the left and right wheels, the cornering power for each of the left and right wheels is CP ₀ , and the average cornering power of the left and right wheels is CP _0. It becomes. On the other hand, when the vehicle turns, load movement occurs from the turning inner wheel to the turning outer wheel, and when the load difference between the turning inner wheel and the turning outer wheel becomes ΔW, the load of the turning outer wheel is W ₀ + 1 / 2ΔW, and the load of the turning inner wheel is W ₀₋₁ / 2ΔW, the cornering power of the outer turning wheel is CP ₁ , and the cornering power of the inner turning wheel is CP ₂ . The average cornering power of the turning inner and outer wheels is (CP ₁ + CP ₂ ) / 2, and as you can see from the figure, the average cornering power (CP ₁ + CP ₂ ) / 2 during turning causes load movement between the left and right wheels. smaller than the average cornering power CP ₀ of If not. Therefore, the steering characteristics of the vehicle can be changed by changing the roll rigidity distribution of the front and rear wheels. Specifically, if the roll rigidity on the front wheel side is increased, the load movement between the left and right wheels on the front wheel side is increased, and the cornering power on the front wheel side is reduced, thereby increasing the understeer tendency. On the other hand, if the roll rigidity on the rear wheel side is increased, the load movement between the left and right wheels on the rear wheel side is increased, and the cornering power on the rear wheel side is reduced, thereby reducing the tendency of understeer.

Roll stiffness distribution in the system 10, the front wheel side stabilizer device 14F is the roll restraining force to be generated (hereinafter referred to as "front-wheel-side roll restraining force") F _F and the rear wheel side stabilizer devices 14R is generating roll restraining force should (hereinafter sometimes referred to as "rear-wheel-side roll restraining force") roll restraining force which is the sum of the F _R (hereinafter referred to as "total roll restraining force") F _T, that is, the vehicle body A roll restraining force distribution ratio (hereinafter sometimes referred to as “distribution ratio”) X, which is a ratio of a front wheel side roll restraining force to a roll restraining force having a magnitude corresponding to the received roll moment, is adopted. Normally, the reference distribution ratio X ₀ is set. Incidentally, in this reference distribution ratio X ₀ , the stability factor k as the steer characteristic index amount that indicates the steering characteristic of the vehicle is usually the reference stability factor k ₀ . Here, the stability factor k indicates the degree of the understeering tendency or oversteering tendency. The larger the value, the stronger the understeering tendency, and the smaller the value, the weaker the understeering tendency. Indicates. In other words, the larger the value, the weaker the oversteer tendency, and the smaller the value, the stronger the oversteer tendency.

  Further, when the vehicle turns, a change in the cornering power is also caused by the load movement between the front and rear wheels caused by the acceleration / deceleration of the vehicle. Specifically, when the vehicle is accelerated, the load on the rear wheel side increases. If the load applied to the wheel increases, as shown in FIG. 6, the cornering power of the wheel increases, so that the cornering power of the rear wheel increases as the load on the rear wheel increases. In other words, the understeer tendency becomes stronger during the acceleration turning of the vehicle. On the other hand, when the vehicle decelerates, the load on the front wheels increases and the cornering power of the front wheels increases. In other words, the understeer tendency is weakened when the vehicle turns at a reduced speed. Further, if the roll rigidity is increased, as described above, the load movement between the left and right wheels is increased and the cornering power is reduced. It varies depending on whether or not it is executed. Specifically, for example, when roll suppression control is executed during acceleration turning of the vehicle, an increase in cornering power of the rear wheels due to acceleration of the vehicle is suppressed, and roll suppression control is not executed. In comparison, the understeer tendency is weakened. On the other hand, when roll suppression control is executed during deceleration turning of the vehicle, an increase in the cornering power of the front wheels due to vehicle deceleration is suppressed, and an understeer tendency is stronger than when roll suppression control is not executed. . That is, the relationship between the longitudinal acceleration Gzg as the pitch moment index amount that indicates the pitch moment that the vehicle body receives due to the acceleration / deceleration of the vehicle and the stability factor k that indicates the steering characteristic is shown in FIG. As indicated by the solid line, when the roll suppression control is not executed, it is indicated by the dotted line in FIG. In addition, when the value of the longitudinal acceleration Gzg is positive, the vehicle is accelerating, and when the value of the longitudinal acceleration Gzg is negative, it means that the vehicle is decelerating.

  As can be seen from the figure, when roll suppression control is executed, the degree of change in steering characteristics due to acceleration / deceleration of the vehicle is suppressed compared to when roll suppression control is not executed. For this reason, for example, when the roll suppression control is executed during deceleration turning of the vehicle, the understeer tendency becomes stronger than the case where the roll suppression control is not executed, and the turning ability of the vehicle may be reduced. On the other hand, when roll suppression control is executed during acceleration turning of the vehicle, the understeer tendency becomes weaker than when it is not executed, and there is a possibility that it becomes difficult to suppress spins accompanying acceleration turning of the vehicle. Therefore, in the present system 10, even when the roll suppression control is executed, the longitudinal acceleration Gzg is set so as to change the steering characteristics of the vehicle by the acceleration / deceleration of the vehicle, similarly to the case where the roll suppression control is not executed. Based on this, the roll stiffness distribution is changed.

As for specific control, in order to suppress rolling of the vehicle body by both the front-wheel-side stabilizer device 14F and the rear wheel-side stabilizer devices 14R, and a front-wheel-side roll restraining force F _F and the rear-wheel-side roll restraining force F _R total sums roll restraining force F _T and is first determined based on the lateral acceleration of the roll-moment index amount which indicates roll moment acting on the vehicle body. More specifically, based on the estimated lateral acceleration Gyc estimated based on the steering wheel operating angle δ and the vehicle traveling speed v, and the actually measured actual lateral acceleration Gyr, the controlled lateral acceleration used for the control is determined. The acceleration Gy ^* is determined according to the following equation:
Gy ^* = K _A · Gyc + K _B · Gyr (K _A and K _B are gains)
Based on the control lateral acceleration Gy ^* thus determined, the total roll restraining force _FT is determined according to the following equation.
F _T = K _C · Gy ^*
Here, K _C is a control gain for determining a roll restraining force having a magnitude corresponding to the control lateral acceleration Gy ^* .

Total roll restraining force F _T that is determined as described above, based on the roll restraining force distribution ratio X, in a front-wheel-side roll restraining force F _F and the rear-wheel-side roll restraining force F _R, according to the following equation, Distributed.
F _F = X · F _T
F _R = (1-X) · F _T
As described above, the roll restraining force distribution ratio X is set so as to change the steering characteristics of the vehicle by acceleration / deceleration of the vehicle even when the roll restraining control is executed, as in the case where the roll restraining control is not executed. , Based on the longitudinal acceleration Gzg. More specifically, the vehicle steering characteristic is estimated by estimating the stability factor k based on the longitudinal acceleration Gzg, and the distribution ratio X is changed so that the steering characteristic changes to the target steering characteristic. That is, the distribution ratio X is changed based on the estimated stability factor kc.

The estimated stability factor kc is estimated based on the cornering power CP of each wheel that changes as the vehicle turns and accelerates / decelerates. Since the cornering power CP of each wheel is calculated based on the load W applied to each wheel, first, the load W applied to each wheel that changes with turning and acceleration / deceleration of the vehicle is calculated. Specifically, the movement load ΔWr _F between the left and right wheels on the front wheel side and the movement load ΔWr _R between the left and right wheels on the rear wheel side as the vehicle turns are calculated according to the following equations:
ΔWr _F = Gy ^* · m · hr · X ₀ / B _F
ΔWr _R = Gy ^* · m · hr · (1-X ₀ ) / B _R
m: sprung mass hr: roll arm B _F : tread width of front wheel B _R : tread width of rear wheel B _R : front wheel change load ΔWp _F and rear wheel change load ΔWp _R associated with acceleration / deceleration of the vehicle Is calculated according to
ΔWp _F = Gzg · m · hp / 2L
ΔWp _R = −Gzg · m · hp / 2L
hp: pitch arm L: wheel base and load W applied to each wheel that changes as the vehicle turns and accelerates, specifically, load W _FR applied to the right front wheel, load W _FL applied to the left front wheel, right The load W _RR applied to the rear wheel and the load W _RL applied to the left rear wheel are calculated according to the following equations:
W _FR = W _F / 2 + ΔWr _F / 2 + ΔWp _F / 2
W _FL = W _F / 2−ΔWr _F / 2 + ΔWp _F / 2
W _RR = W _R / 2 + ΔWr _R / 2 + ΔWp _R / 2
W _RL = W _R / 2−ΔWr _R / 2 + ΔWp _R / 2
W _F : Shared load on the front wheel side of the vehicle W _R : Shared load on the rear wheel side of the vehicle The cornering power CP corresponding to each wheel is determined based on the load W applied to each wheel calculated in this way. In the controller 96, map data set as shown in FIG. 6, that is, map data of cornering power CP with the load W as a parameter, is stored. With reference to the map data, map data of each wheel is stored. A cornering power CP is determined.

As described above, when the cornering power CP of each wheel is determined, the cornering power CP _FR of the right front wheel and the cornering power CP _{FL of the} left front wheel are summed to determine the total cornering power CP _{F of the} front wheel, and the right rear The cornering power CP _RR of the wheel and the cornering power CP _RL of the left rear wheel are summed to determine the total cornering power CP _R of the rear wheel. So determined the total cornering power CP _F was based on the CP _R, estimated Stay stability factor kc is determined according to the following equation.
kc = m · (L _R · CP _R −L _F · CP _F ) / (2L ² · CP _F · CP _R )
L _F : Distance between center of gravity of front axles L _R : Distance between centers of gravity of rear axles

Next, a target stability factor k ^* indicating a target steering characteristic is determined. Since the steering characteristic at the time of acceleration / deceleration of the target vehicle is the steering characteristic at the time of acceleration / deceleration of the vehicle when roll suppression control is not executed as described above, the target stability factor k ^* is It is determined based on the map data set as shown by the dotted line 7. More specifically, the controller 96 stores map data set as shown by the dotted line in FIG. 7, that is, map data of the target stability factor k ^* having the longitudinal acceleration Gzg as a parameter. The target stability factor k ^* is determined with reference to the map data.

To vary the steering characteristics to index the target stability factor k ^* a steering characteristic of the vehicle, estimated Stay stability factor kc target stability factor k which is a deviation with respect to ^* the stability factor deviation Δk (= k ^* -kc) And the distribution ratio X is changed by changing the control gain based on the value. Specifically, as described above, the vehicle steering characteristics and the distribution ratio X are closely related to each other. The larger the distribution ratio X, that is, the larger the ratio of the front-wheel-side roll restraining force, the lower the tendency to understeer. Becomes stronger, and the lower the distribution ratio X, that is, the greater the ratio of the rear-wheel-side roll restraining force, the weaker the understeer tendency. From this, as the stability factor deviation Δk becomes larger at a positive value, that is, as the target stability factor k ^* is larger than the estimated stability factor kc, the distribution ratio X becomes the reference distribution ratio X to strengthen the understeer tendency. _Greater than ₀ . On the other hand, as the target stability factor k ^* is smaller than the estimated stability factor kc, the distribution ratio X is made smaller than the reference distribution ratio X _{0 in} order to weaken the understeer tendency. Specifically, the distribution ratio X is determined according to the following equation using the control gain K _S that changes based on the stability factor deviation Δk.
X = K _S · X ₀
As shown in FIG. 8, the control gain K _S depends on the stability factor deviation Δk, and is set to increase as the stability factor deviation Δk increases. The stability factor deviation Δk Is set to 1 when the target stability factor k ^* and the estimated stability factor kc have the same value.

Based on the thus-determined distribution ratio X, in a total roll restraining force F _T front-wheel-side roll restraining force F _F and the rear-wheel-side roll restraining force F _R, according to the above formula, when it is distributed, the front wheel target motor rotational angle of the electromagnetic motor 60 of the front wheel side stabilizer apparatus 14F theta ^* is determined based on the roll restraining force F _F, the rear wheel side stabilizer devices 14R based on the rear wheel side roll restraining force F _R of the electromagnetic motor 60 A target motor rotation angle θ ^* is determined. In the controller 96, map data of the target motor rotation angle θ ^{* using} the roll suppression force as a parameter is stored for each stabilizer device 14, and the electromagnetic motors of the stabilizer devices 14F and R are referred to with reference to each map data. 60 target motor rotation angles θ ^* are determined.

Then, the electromagnetic motor 60 is controlled so that the actual motor rotation angle θ becomes the target motor rotation angle θ ^* . In the control of the electromagnetic motor 60, the electric power supplied to the electromagnetic motor 60 is determined based on a motor rotation angle deviation Δθ (= θ ^* −θ) that is a deviation of the actual motor rotation angle θ from the target motor rotation angle θ ^* . The Specifically, it is determined according to a feedback control method based on the motor rotation angle deviation Δθ. Specifically, first, the motor rotation angle deviation Δθ is certified based on the detection value of the motor rotation angle sensor 78 included in the electromagnetic motor 60, and then using that as a parameter, the target supply current i ^* according to the following equation: Is determined.
i ^* = K _P · Δθ + K _I · Int (Δθ)
This equation follows the PI control law. The first term and the second term mean the proportional term and the integral term, respectively, and K _P and K _I mean the proportional gain and the integral gain, respectively. Int (Δθ) corresponds to an integral value of the motor rotation angle deviation Δθ.

Incidentally, the target supply current i ^* indicates the generation direction of the motor force of the electromagnetic motor 60 by its sign, and the electromagnetic motor 60 is controlled based on the target supply current i ^*. The duty ratio for driving the motor 60 and the motor force generation direction are determined. Then, a command regarding the duty ratio and the direction of motor force generation is issued to the inverter 92, and the drive control of the electromagnetic motor 60 based on the command is performed by the inverter 92.

In the present system 10, as described above, the load W applied to each wheel is calculated based on the longitudinal acceleration Gzg, the control lateral acceleration Gy ^*, etc., and the estimated stability factor kc is calculated based on the calculated load W. Although estimated, it is also possible to estimate the estimated stability factor kc directly based on the longitudinal acceleration Gzg. Specifically, the load W applied to each wheel that changes according to the longitudinal acceleration Gzg is measured in the factory, and an estimated stability factor kc that changes according to the longitudinal acceleration Gzg is set in advance based on the measurement result. deep. Specifically, map data as indicated by the solid line in FIG. 7, that is, map data of the estimated stability factor kc using the longitudinal acceleration Gzg as a parameter is stored in the controller 96. The estimated stability factor kc can be estimated based on the longitudinal acceleration Gzg with reference to the map data.

<Control program>
In the present system 10, the stabilizer device 14 is controlled by the controller 96 with a short time interval (for example, several milliseconds) while the ignition control is turned on by the stabilizer control program shown in the flowchart of FIG. Done by being executed. The control flow will be briefly described below with reference to the flowchart shown in the figure. This program is executed for both the front wheel side stabilizer device 14F and the rear wheel side stabilizer device 14R.

In the processing according to this program, first, in step 1 (hereinafter simply referred to as “S1”; the same applies to other steps), the actual lateral acceleration Gyr detected by the lateral acceleration sensor 104 and the estimated lateral acceleration Gyc are described. Based on the above, the control lateral acceleration Gy ^* is determined. In S2, the total roll restraining force _FT is determined based on the determined control lateral acceleration Gy ^* . Next, in S3, the movement loads ΔWr _F and ΔWr _R between the left and right wheels in the front and rear wheels are determined based on the control lateral acceleration Gy ^* . Subsequently, in S4, the longitudinal acceleration Gzg is detected by the longitudinal acceleration sensor 106, and in S5, the change loads ΔWp _F and ΔWp _{FR of} the front and rear wheels are determined based on the detected longitudinal acceleration Gzg. In S6, loads W _FR , W _FL , W _RR , W _RL applied to the respective wheels are determined. In S7, the respective wheels are determined based on the loads W _FR , W _FL , W _RR , W _{RL applied} to the respective wheels. the cornering power _{CP FR, CP FL, CP RR} , CP RL are calculated, the total cornering power CP _F of the front and rear wheels, CP _R is determined.

In S8, based the total cornering power CP _F of the determined front and rear wheels, the CP _R, map the estimated stability factor kc is determined according to the above formula, in S9, it is set as shown in dotted lines in FIG. 7 With reference to the data, the target stability factor k ^* is determined based on the longitudinal acceleration Gzg. Next, in S10, a stability factor deviation Δk is determined based on the estimated stability factor kc and the target stability factor k ^*, and in S11, roll suppression is performed based on the determined stability factor deviation Δk. A force distribution ratio X is determined. Then, in S12, based on the roll restraining force distribution ratio X that has been determined, the total roll restraining force F _T is distributed to the front-wheel-side roll restraining force F _F and the rear-wheel-side roll restraining force F _R, in S13 The target motor rotation angle θ ^* of each electromagnetic motor 60 of the front wheel side stabilizer device 14F and the rear wheel side stabilizer device 14R is determined. Subsequently, in S14, the actual motor rotation angle θ of each electromagnetic motor 60 is acquired based on the motor rotation angle sensor 78 of each electromagnetic motor 60. In S15, the motor rotation angle deviation Δθ of each electromagnetic motor 60 is determined. The In S16, the target supply current i ^* of each electromagnetic motor 60 is determined based on the motor rotation angle deviation Δθ in accordance with the formula according to the aforementioned PI control law. In S17, the target supply current i ^* of each electromagnetic motor 60 is determined ^. After the control signal based on is transmitted to the inverter 92 corresponding to each electromagnetic motor 60, one execution of this program ends.

<Functional configuration of controller>
The controller 96 that executes the above program can be considered to have a functional configuration as shown in FIG. 10 in view of its execution processing. As can be seen from the figure, the controller 96, S1, functional unit that executes processing of S2, i.e., as a functional portion to determine the total roll restraining force F _T having a magnitude corresponding to the roll moment acting on the vehicle body, the roll restraining force the decision unit 120, a functional portion to execute the processing in S3 to S12, i.e., as a functional unit for distributing the total roll restraining force F _T in the front-wheel-side roll restraining force F _F and the rear-wheel-side roll restraining force F _R, the roll the restraining force distribution unit 122, a functional portion to execute the processing in S13 through S17, i.e., functional unit for controlling the operation of each actuator 26 on the basis of the front wheel side roll restraining force F _F and the rear-wheel-side roll restraining force F _R As shown, the actuator operation control unit 124 is provided. The roll suppression force distribution unit 122 is a functional unit that executes the processes of S3 to S8, that is, a functional unit that estimates the stability factor k that indexes the steering characteristic of the vehicle. As the functional units that execute the processes of S9 to S11, that is, the functional units that determine the roll restraining force distribution ratio X based on the estimated stability factor k, the roll restraining force distribution ratio determining unit 128 is provided. Yes.

<Modification 1>
In the system 10, even when the roll suppression control is executed, the estimated steering characteristic is changed to change the steering characteristic of the vehicle by the acceleration / deceleration of the vehicle, similarly to the case where the roll suppression control is not executed. Based on this, the roll stiffness distribution is changed so that the steering characteristic of the vehicle becomes the target steering characteristic. Referring to the drawing, the roll stiffness so that the steering characteristic of the vehicle that changes according to the longitudinal acceleration Gzg as shown by the solid line in FIG. 7 changes according to the longitudinal acceleration Gzg as shown by the dotted line in FIG. Distribution is changed. That is, the estimated stability factor kc (solid line in FIG. 7) that indicates the steering characteristic when the roll suppression control is executed is the stability factor when the vehicle is not subjected to the pitch moment (Gzg = 0), that is, the reference stability. When the factor k _{0 is} larger, the roll stiffness distribution is changed so that the ratio of the front-wheel-side roll restraining force is increased to increase the understeer tendency, while the estimated stability factor kc (solid line in FIG. 7) is When it is smaller than the ability factor k ₀ , the roll stiffness distribution is changed so that the ratio of the rear wheel side roll restraining force is increased in order to weaken the understeer tendency.

As described above, the roll stiffness distribution may be changed using the stability factor k that indicates the steering characteristic of the vehicle, but the roll stiffness distribution is changed based on the longitudinal acceleration Gzg without using the stability factor k. It is also possible. That is, as can be seen from FIG. 7, when the vehicle is accelerated (Gzg> 0), the understeer tendency is strengthened as the vehicle is accelerated, and when the vehicle is decelerated (Gzg <0), the understeer tendency is increased as the vehicle is decelerated. What is necessary is just to change roll rigidity distribution so that it may weaken. Specifically, by using the control gain K _G that changes based on the longitudinal acceleration GZG, may be determined distribution ratio X in accordance with the following equation.
X = K _G · X ₀
The control gain K _G, as shown in FIG. 11, from 1 as the longitudinal acceleration Gzg is 0 and is set to be 1 when made, become a value larger than 1 as the vehicle accelerates, the vehicle is decelerated It is set to a small value. Thus, even if the distribution ratio X is changed or the roll suppression control is executed, the steering characteristics of the vehicle can be changed by the acceleration / deceleration of the vehicle as in the case where the roll suppression control is not executed. It becomes possible.

<Modification 2>
In the above-described system, even when the roll suppression control is executed, the roll stiffness distribution is changed so that the vehicle steering characteristics are changed by the acceleration / deceleration of the vehicle, as in the case where the roll suppression control is not executed. However, it is also possible to change the roll stiffness distribution so that the steering characteristics of the vehicle are not changed by the acceleration / deceleration of the vehicle. More specifically, the roll rigidity so that the steering characteristic of the vehicle that changes according to the longitudinal acceleration Gzg as shown by the solid line in FIG. 1 is constant even if the longitudinal acceleration Gzg changes as shown by the one-dot chain line in FIG. Change the distribution. In other words, even if the longitudinal acceleration Gzg changes, the vehicle steering characteristics are such that the vehicle steering characteristics when the longitudinal acceleration Gzg is 0, that is, the roll stiffness distribution so that the steering characteristics indicated by the reference stability factor k ₀ are indicated. Is changed.

Specifically, when changing the roll restraining force distribution ratio X based on the estimated stability factor kc, the stability factor deviation Δk is calculated using the target stability factor k ^* as the reference stability factor k _0. Then, based on the stability factor deviation Δk, the roll restraining force distribution ratio X may be determined as described above. That is, by determining the target stability factor k ^* as the reference stability factor k ₀ in S9 of the stabilizer control program (FIG. 9) of the system 10, the vehicle steering characteristics are not changed even by the acceleration / deceleration of the vehicle. It becomes possible to change the roll restraining force distribution ratio X.

It is the graph which showed typically the mode of the change of the steering characteristic of the vehicle by the acceleration / deceleration of the vehicle. It is a schematic diagram which shows the whole structure of the stabilizer system for vehicles which is a claimable invention. It is a schematic diagram which shows the stabilizer apparatus with which the stabilizer system for vehicles of FIG. 1 is provided in the viewpoint from vehicle upper direction. It is a schematic diagram which shows the stabilizer apparatus with which the stabilizer system for vehicles of FIG. 1 is provided from the viewpoint from the vehicle front. It is a schematic sectional drawing which shows the actuator with which a stabilizer apparatus is provided. It is the graph which showed typically the relationship between cornering power and the load concerning a wheel. 5 is a graph schematically showing changes in steering characteristics of a vehicle due to acceleration / deceleration of the vehicle when roll suppression control is executed and when it is not executed. It is a graph which shows the relationship between a stability factor deviation and the gain which depends on it. It is a flowchart which shows a stabilizer control program. It is a block diagram which shows the function of the control apparatus which manages control of a stabilizer system. It is a graph which shows the relationship between a longitudinal acceleration and the gain which depends on it.

Explanation of symbols

  10: Stabilizer system for vehicle 14: Stabilizer device (front wheel side stabilizer device) (rear wheel side stabilizer device) 20: Stabilizer bar 22: Stabilizer bar member 26: Actuator 50: Torsion bar portion 52: Arm portion 60: Electromagnetic motor 62: Reducer 64: Housing 82: Flexible gear (output unit) 90: Electronic control unit (ECU) (control device) 120: Roll suppression force determination unit 122: Roll suppression force distribution unit

Claims (8)

Provided corresponding to the front and rear wheels, each having a stabilizer bar and an actuator, and generating a roll restraining force that depends on the torsional reaction force of the stabilizer bar, and changing the roll restraining force by the actuator Possible front wheel side stabilizer device and rear wheel side stabilizer device;
(a) The total roll restraining force to be generated by each of the front wheel side stabilizer device and the rear wheel side stabilizer device is determined based on the roll moment index amount indicating the roll moment received by the vehicle body due to the turning of the vehicle. A roll restraining force determining unit that performs (b) the roll restraining force determined by the roll restraining force determining unit based on the roll restraining force distribution ratio and the roll restraining force that the front wheel side stabilizer device should generate. A roll restraining force distribution portion that distributes to a certain front wheel side roll restraining force and a rear wheel side roll restraining force that is a roll restraining force that should be generated by the rear wheel side stabilizer device, and is distributed by the roll restraining force distributing portion. Based on each of the front wheel side roll restraining force and the rear wheel side roll restraining force, the front wheel side stabilizer device and the rear wheel side star A vehicle stabilizer system equipped with a control device for controlling the operation of the actuator, each having a riser system,
The vehicle stabilizer system configured such that the roll restraining force distribution unit changes the roll restraining force distribution ratio based on a pitch moment index amount that indexes a pitch moment received by a vehicle body due to acceleration / deceleration of the vehicle. .   When the roll restraining force distribution unit has a value that indicates the pitch moment received by the vehicle body due to acceleration of the vehicle, the roll restraining force distribution unit compares the front wheel side with a value that does not become such a value. The vehicle stabilizer system according to claim 1, wherein the roll restraining force distribution ratio is changed so that a ratio of the roll restraining force is increased.   When the roll restraining force distribution unit has a value that indicates the pitch moment that the vehicle body receives due to acceleration of the vehicle, the larger the pitch moment index amount, the greater the front wheel side roll restraining force. The vehicle stabilizer system according to claim 2, wherein the roll restraining force distribution ratio is changed so that the ratio increases.   When the roll suppression force distribution unit is a value that indicates the pitch moment that the vehicle body receives due to deceleration of the vehicle, the rear wheel The vehicle stabilizer system according to any one of claims 1 to 3, wherein the roll restraining force distribution ratio is changed so that a ratio of a side roll restraining force is increased.   When the roll restraining force distribution unit has a value that indicates the pitch moment that the vehicle body receives due to deceleration of the vehicle, the larger the pitch moment index amount, the larger the rear wheel side roll restraining force. The stabilizer system for vehicles of Claim 4 comprised so that the said roll suppression force distribution ratio might be changed so that ratio might become large. When the steering characteristic index amount is defined as an index indicating the degree of the understeer tendency or oversteer tendency that is the steering characteristic of the vehicle,
The roll restraining force distribution unit is configured to estimate the steering characteristic index amount based on the pitch moment index amount and to change the roll restraining force distribution ratio based on the estimated steer characteristic index amount. The vehicle stabilizer system according to claim 1.   When the roll restraining force distribution unit is a value that indicates that the estimated steer characteristic index amount has a stronger understeer tendency than the steer characteristic index amount when the vehicle body is not receiving a pitch moment, such as The stabilizer system for vehicles according to claim 6 constituted so that said roll restraining force distribution ratio may be changed so that a ratio of said front wheel side roll restraining force may become large compared with a case where it does not become a value.   When the roll restraining force distribution unit is a value that indicates that the estimated steer characteristic index amount has a lower understeer tendency than the steer characteristic index amount when the vehicle body does not receive a pitch moment, such as The vehicle stabilizer according to claim 6 or 7, wherein the roll restraining force distribution ratio is changed so that a ratio of the rear wheel side roll restraining force is larger than a case where the value is not a value. system.

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