JP5151307B2 - suspension - Google Patents

Description

  The present invention relates to a vehicle suspension.

Conventionally, a suspension described in Patent Document 1 is known as a suspension for improving the riding comfort of a vehicle. This suspension is a trailing arm type rear suspension that is set so that the instantaneous center of rotation of the axle is positioned forward and above the wheel center and the wheel center trajectory is tilted backward when the unsprung strokes up and down. Thus, the longitudinal force input from the rear tire is reduced, and the harshness is reduced without lowering the rigidity of the bush.
JP 2001-270313 A

  However, in the above suspension, there is a problem that the longitudinal force input from the tire is not sufficiently reduced only by tilting the wheel center locus backward.

  In addition, when the traveling vehicle gets over an obstacle, the distance between the front and rear forces input from the front tire and the rear tire varies depending on the vehicle speed. However, in the above suspension, the suspension arrangement and the like are fixed. When traveling at a vehicle speed other than the predetermined vehicle speed, there is a problem that the longitudinal force input from the tire cannot be sufficiently reduced.

  Accordingly, an object of the present invention is to provide a suspension capable of reducing the longitudinal force input from a tire as a whole vehicle.

  Here, as a result of intensive studies, the inventors have come to the knowledge that the arrangement of the attenuator also affects the reduction of the longitudinal force input from the tire to the unsprung portion. From this, we succeeded in deriving the relationship with the longitudinal force input to the unsprung mass.

Therefore, the suspension according to the present invention has been made based on the knowledge of the above-mentioned inventors, and extends in the vehicle longitudinal direction and extends between the vehicle body and the spindle shaft, and extends in the vehicle vertical direction. In a suspension equipped with an attenuator arranged between the vehicle body and the spindle shaft, when the unsprung strokes up and down, the rigidity of the arm member, the rigidity around the spindle axis, the attenuation coefficient of the attenuator, The inclination angle formed by the attenuator with respect to the direction line, the opposite angle formed by the axis of the direction in which the arm member rigidity acts on the vehicle longitudinal direction line, the position of the unsprung center of gravity and the direction in which the arm member rigidity acts vehicle vertical direction of the displacement amount of the shaft, and a front suspension damping force of gravity position attenuator unsprung is calculated based on the vehicle front-rear direction of the shift amount between the direction of the axis to act input As the longitudinal force is canceled is inputted to the longitudinal force and the rear suspension to the rigidity of the arm member, the spindle axis of the rigid damping coefficient of the attenuator, the inclination angle attenuator with respect to the vehicle vertical direction of the line An angle formed by an axis in a direction in which the rigidity of the arm member acts with respect to a line in the longitudinal direction of the vehicle, an amount of deviation in the vehicle vertical direction between the unsprung center of gravity position and an axis in the direction in which the rigidity of the arm member acts, and A deviation amount in the vehicle front-rear direction between the unsprung center-of-gravity position and the axis in the direction in which the damping force of the attenuator acts is set.

  According to this suspension, the suspension is set so that the longitudinal force input to the front suspension and the longitudinal force input to the rear suspension are offset in consideration of the setting of the attenuator. The longitudinal force input from the tire can be effectively reduced, and vibration in the longitudinal direction of the unsprung vehicle can be suppressed to improve the riding comfort of the vehicle.

Then, the rigidity of the arm member, the rigidity around the spindle axis, the attenuation coefficient of the attenuator, and the vehicle vertical direction are set so that the longitudinal force input to the front suspension and the longitudinal force input to the rear suspension are offset. The inclination angle formed by the attenuator with respect to this line, the opposite angle formed by the axis of the direction in which the rigidity of the arm member acts on the line in the vehicle longitudinal direction, the direction in which the position of the center of gravity under the spring and the rigidity of the arm member acts The amount of deviation in the vehicle vertical direction from the axis of the vehicle and the amount of deviation in the vehicle longitudinal direction from the unsprung center-of-gravity position and the axis in the direction in which the damping force of the attenuator acts are set. For this reason, as a whole vehicle, the longitudinal force input from the tire can be reduced with higher accuracy, and vibration in the longitudinal direction of the unsprung vehicle can be suppressed to improve the riding comfort of the vehicle.

The suspension according to the present invention includes an arm member that extends in the vehicle longitudinal direction and is disposed between the vehicle body and the spindle shaft, and an attenuator that extends in the vehicle vertical direction and is disposed between the vehicle body and the spindle shaft. The suspension includes a vehicle speed detecting means for detecting the vehicle speed, and a setting changing means for changing the setting of the suspension. The setting changing means moves the unsprung up and down according to the vehicle speed detected by the vehicle speed detecting means. When a stroke is performed, the rigidity of the arm member, the rigidity around the spindle axis, the attenuation coefficient of the attenuator, the inclination angle formed by the attenuator with respect to the vehicle vertical line, and the rigidity of the arm member with respect to the vehicle longitudinal line The opposite angle formed by the axis in the direction to be driven, the amount of deviation in the vehicle vertical direction between the unsprung center of gravity position and the axis in the direction in which the rigidity of the arm member acts, and the unsprung center of gravity position and the damping force of the attenuator act. As the longitudinal force inputted to the front-rear force and rear suspension which is input to the front suspension is calculated based on the vehicle longitudinal direction of the deviation between the direction of the axis is offset, the rigidity of the arm member, the spindle axis Rigidity, damping coefficient of the attenuator, inclination angle formed by the attenuator with respect to the vehicle vertical direction line, anti-angle formed by the axis of the direction in which the rigidity of the arm member acts on the vehicle longitudinal direction line, center of gravity under the spring Set the amount of deviation in the vehicle vertical direction between the position and the axis in the direction in which the rigidity of the arm member acts, and the amount of deviation in the vehicle longitudinal direction between the unsprung center of gravity and the axis in the direction in which the damping force of the attenuator acts It is characterized by changing.

  According to this suspension, the setting of the suspension is changed so that the longitudinal force input to the front suspension and the longitudinal force input to the rear suspension are offset according to the vehicle speed while taking into account the setting of the attenuator. Therefore, the longitudinal force input from the tire can be effectively reduced as a whole vehicle regardless of the change in the vehicle speed, and the vibration in the longitudinal direction of the unsprung vehicle can be suppressed to improve the riding comfort of the vehicle. Can do.

Then, depending on the vehicle speed, the rigidity of the arm member, the rigidity around the spindle axis, and the attenuation coefficient of the attenuator so that the longitudinal force input to the front suspension and the longitudinal force input to the rear suspension are offset. And the inclination angle formed by the attenuator with respect to the vehicle vertical line, the opposite angle formed by the axis of the direction in which the rigidity of the arm member acts on the vehicle longitudinal direction line, the unsprung center of gravity position and the arm member The amount of deviation in the vehicle vertical direction from the axis in which the rigidity acts and the amount of deviation in the vehicle longitudinal direction from the unsprung center of gravity position and the axis in the direction in which the damping force of the attenuator acts are changed. For this reason, the longitudinal force input from the tire can be reduced with higher accuracy, and vibration in the vehicle longitudinal direction under the spring can be suppressed to improve the riding comfort of the vehicle.

  Moreover, it is preferable to further comprise arm member arrangement changing means for changing the arrangement of the arm members and attenuator arrangement changing means for changing the arrangement of the attenuators. According to this suspension, by changing the arrangement of the arm member, the opposite angle formed by the axis in the direction in which the rigidity of the arm member acts on the line in the longitudinal direction of the vehicle, the position of the center of gravity under the spring and the arm member It is possible to change the setting of the amount of deviation in the vehicle vertical direction from the axis in the direction in which the stiffness acts. In addition, by changing the arrangement of the attenuator, the inclination angle formed by the attenuator with respect to the vehicle vertical direction line, and the vehicle longitudinal direction between the unsprung center of gravity position and the axis in which the attenuator's damping force acts are applied. The setting of the deviation amount can be changed.

  ADVANTAGE OF THE INVENTION According to this invention, the longitudinal force input from a tire can be reduced as a whole vehicle, and the riding comfort of a vehicle can be improved.

  Hereinafter, embodiments of a suspension according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[First Embodiment]
A suspension 1 according to a first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram schematically illustrating a vehicle to which the suspension according to the embodiment is applied. FIG. 2 is a diagram for explaining the arrangement of the suspension.

  The suspension 1 applied to the vehicle 2 includes a front suspension 3 and a rear suspension 4. In the present embodiment, for ease of explanation, the front suspension 3 and the rear suspension 4 are assumed to be the same type of suspension, and the suspension arm is configured as one. Further, a symbol with a subscript “f” indicates that it relates to the front suspension, and a symbol with a subscript “r” indicates that it relates to the rear suspension.

  The front suspension 3 absorbs vibration input from the front tire 6 and suspends the vehicle body 5 in front of the vehicle, and includes an arm 7 and an absorber 8.

  The arm 7 is a member that is connected between the vehicle body 5 and the front tire 6 to control the movement of the front tire 6. The arm 7 is connected to a hub (not shown) that rotatably supports the spindle shaft 9, and extends toward the front of the vehicle while slightly tilting upward from the vehicle, and is connected to the vehicle body 5.

The connection point between the arm 7 and the hub is disposed only at a position shifted to the vehicle lower distance H _f the center of gravity of the unsprung front suspension 3. In the present embodiment, the unsprung center of gravity of the front suspension 3 is located on the spindle shaft 9 of the front tire 6.

By the way, when a force in the vehicle front-rear direction is applied to a certain point of the front suspension 3, there is a point where the direction in which this force is applied coincides with the direction in which the front suspension 3 moves. This is referred to as the longitudinal elastic main axis _Af . In this embodiment, since the arm is constituted by one, a line connecting the point where the arm 7 and the hub are connected and the point where the arm 7 and the vehicle body 5 are connected, that is, the center of the arm 7 is used. The passing axis is the longitudinal elastic principal axis _Af . The angle at which the longitudinal elastic main axis _Af is inclined upward with respect to the horizontal line D, which is a line in the vehicle longitudinal direction, is referred to as the longitudinal elastic main axis upper angle β _f .

In addition, a compliance bush 10 is fitted into the arm 7 at a connection portion with the vehicle body 5. The compliance bush 10 is a member that elastically connects the vehicle body 5 and the arm 7 and absorbs vibrations in the vehicle longitudinal direction. For this reason, the rigidity of the arm 7, that is, the longitudinal elastic principal axis rigidity K _xf of the longitudinal elastic principal axis A _f is determined by the spring constant of the compliance bush 10.

The absorber 8 is a member that is connected between the vehicle body 5 and the front tire 6 and attenuates the force input from the front tire 6 to the front suspension 3 while stroking in the vehicle vertical direction. The absorber 8 is connected to a hub that rotatably supports the spindle shaft 9. The absorber 8 extends upward from the vehicle while tilting forward from the vehicle and is connected to the vehicle body 5. The connection point between the arm 7 and the hub is disposed only at a position offset rearwardly distance L _f the center of gravity of the unsprung front suspension 3 side (spindle shaft 9). The absorber 8 is configured by incorporating a coil spring (not shown).

Here, the axis in the direction in which the damping force of the absorber 8 acts is referred to as a damping main axis _Bf . In the present embodiment, the line connecting the point where the absorber 8 and the hub are connected to the point where the absorber 8 and the vehicle body 5 are connected, that is, the axis passing through the center of the absorber 8 is the damping main axis _Bf . In addition, an angle at which the absorber 8 (attenuation main axis B _f ) is inclined forward with respect to the vertical line E that is a line in the vehicle vertical direction is referred to as an attenuation main axis forward inclination angle α _f .

  The rear suspension 4 absorbs vibration input from the rear tire 11 and suspends the vehicle body 5 at the rear of the vehicle, and includes an arm 12 and an absorber 13.

  The arm 12 is a member that is connected between the vehicle body 5 and the rear tire 11 and controls the movement of the rear tire 11. The arm 12 is connected to a hub (not shown) that rotatably supports the spindle shaft 14. The arm 12 extends toward the front of the vehicle while slightly tilting upward from the vehicle, and is connected to the vehicle body 5.

The connection point between the arm 12 and the hub is disposed at a position shifted by the vehicle downwardly a distance H _r the center of gravity under the rear suspension 4 side spring. It is assumed that the unsprung center of gravity position on the rear suspension 4 side is on the spindle shaft 14 of the rear tire 11.

By the way, when a force in the vehicle front-rear direction is applied to a certain point of the rear suspension 4, there is a point where the direction in which this force is applied and the direction in which the rear suspension 4 moves, and a virtual axis through which this point passes, It is called the front-rear elastic main axis _Ar . In this embodiment, since the arm is composed of one arm, a line connecting the point where the arm 12 and the hub are connected to the point where the arm 12 and the vehicle body 5 are connected, that is, the center of the arm 12 is used. The passing axis is the longitudinal elastic main axis _Ar . The elastic main axis A _r longitudinal with respect to a horizontal line D which is the longitudinal direction of the line vehicle corners slopes upward, that the front and rear principal elastic axis dihedral beta _r.

In addition, a compliance bush 15 is fitted into the arm 12 at a connection portion with the vehicle body 5. The compliance bush 15 is a member that elastically connects the arm 12 and the vehicle body 5. As shown in FIG. 3, the compliance bush 15 is formed in a substantially cylindrical shape and is press-fitted into a bush mounting hole 21 provided in the lower portion of the vehicle body 5. The compliance bush 15 is fixed to the vehicle body 5 and formed of an elastic material such as rubber, and an arm attachment that is positioned on the radially inner side of the elastic portion 22 and attaches the arm 12 so as to be swingable around the axis. Part 23. The elastic portion 22 and the arm attachment portion 23 are connected via a bearing (not shown) that rotates around the axis of the compliance bush 15, and the longitudinal elastic main shaft rigidity changing device 20 attached to the vehicle body 5 It is configured to be rotated. This longitudinal elastic main shaft stiffness changing device 20 is constituted by a motor or the like, and rotates the compliance bush 15 to change the spring constant in the direction of the longitudinal elastic main shaft A in the compliance bush 15 to change the longitudinal elastic main shaft stiffness K. _xr is changed.

  In addition, the elastic portion 22 of the compliance bush 15 is formed with an edge 24 (a hole provided in the elastic portion 22). The tickles 24 are formed one by one in the vehicle vertical direction with the arm attachment portion 23 interposed therebetween.

FIGS. 3 (a) shows a case where the front and rear principal elastic axis dihedral beta _r is relatively large, FIG. 3 (b) shows a case longitudinal elastic main axis dihedral beta _r is relatively small.

As shown in FIG. 3A, the longitudinal elastic principal axis A _r is large, and when the arm 12 and a part of the curl 24 overlap each other in a side view of the vehicle, the space of the curl 24 causes the longitudinal elastic main axis A The density of the elastic portion 22 in the _r direction is reduced. For this reason, the spring constant of the compliance bush 15 in the front-rear elastic main axis _Ar direction is reduced, and the front-rear elastic main axis rigidity K _xr is reduced. On the other hand, as shown in FIG. 3 (b), before and after the principal elastic axis dihedral beta _r is small, in the vehicle side view, the non-overlapping arm 12 and currant 24, the compliance bush 15 before and after the elastic main axis A _r direction Since the spring constant is hardly affected by the curl 24, the longitudinal elastic main shaft rigidity K _xr is increased.

Thus, the front and rear principal elastic axis dihedral beta _r varies, vary the spring constant of the front and rear principal elastic axis A _r direction in compliance bush 15 according to the position of the arm 12 against the currant 24, rigidity of the arm 12, i.e., The longitudinal elastic principal axis stiffness K _xr varies.

Further, a longitudinal elastic main shaft arrangement changing device 16 is arranged between the arm 12 and the hub. The front / rear elastic main shaft arrangement changing device 16 moves the arm 12 to change the arrangement of the front / rear elastic main axis _Ar . For example, as shown in FIG. 4, an actuator 19 that rotates a screw screw 18 around an axis is fixed to a hub 17 that rotatably supports a spindle shaft 14, as shown in FIG. The screw screw 18 and the arm 12 are connected by a ball joint. Then, by rotating the screw thread 18 by the actuator 19, the vehicle of the one end of the arm 12 is moved in the vertical direction of the vehicle, and the principal elastic axis dihedral beta _r before and after the unsprung gravity center position and the longitudinal elastic main axis A _r a shift amount H _r in the vertical direction, and changes the.

The absorber 13 is a member that is connected between the vehicle body 5 and the rear tire 11 and attenuates the force input from the rear tire 11 to the rear suspension 4 while stroking in the vehicle vertical direction. The absorber 13 is connected to a hub that rotatably supports the spindle shaft 14. The absorber 13 extends upward from the vehicle while tilting forward from the vehicle, and is connected to the vehicle body 5. The connection point between the arm 12 and the hub is disposed only at a position offset rearwardly a distance L _r the center of gravity of the unsprung rear suspension 4 side (spindle shaft 14). The absorber 13 is configured by incorporating a coil spring (not shown).

The absorber 13 is a damping force variable type attenuator, and the damping coefficient changing device 26 can change the damping coefficient of the absorber 13. The damping coefficient changing device 26 changes the damping force of the absorber 13 by, for example, changing the flow resistance of the working fluid filled in the absorber 13, and thereby the absorber 13 (damping main shaft B). The attenuation coefficient C of _r ) is changed.

Here, the axis in the direction in which the damping force of the absorber 13 acts is referred to as a damping main axis _Br . In the present embodiment, the line connecting the point where the absorber 13 and the hub are connected to the point where the absorber 13 and the vehicle body 5 are connected, that is, the axis passing through the center of the absorber 13 is the damping main axis _Br . Further, an angle at which the absorber 13 (attenuation main axis B _r ) is tilted forward with respect to a vertical line E that is a line in the vertical direction of the vehicle is referred to as an attenuation main axis forward inclination angle α _r .

A damping main shaft arrangement changing device 25 is arranged between the absorber 13 and the hub. The attenuation spindle the adjustment apparatus 25 moves the absorber 13, it is intended to change the arrangement of the damping spindle B _r. In the damping main shaft arrangement changing device 25, for example, as shown in FIG. 5, an actuator 29 that rotates a screw screw 28 around an axis is fixed to a hub 17 that rotatably supports a spindle shaft 14. The screw screw 28 and the absorber 13 are connected by a ball joint. Then, by rotating the screw thread 28 by the actuator 29 to move the end of the absorber 13 in the vehicle longitudinal direction, a damping spindle forwardly tilting alpha _r, in the vehicle longitudinal direction between the unsprung gravity center position and the attenuation spindle B deviation The quantity L _r is changed.

  Next, a method for setting the suspension 1 will be described.

  First, an initial setting method for the suspension 1 will be described. The initial setting of the suspension 1 is the same for the front suspension 3 and the rear suspension 4, and will be described together.

  First, when the unsprung strokes up and down, the vehicle longitudinal force (hereinafter referred to as “front-rear force”) input from the front tire 6 and the rear tire 11 to the front suspension 3 and the rear suspension 4 respectively is referred to as Ftv (v ). When the specifications of the suspension 1 are as follows, the longitudinal force Ftv (v) input from the front tire 6 and the rear tire 11 to the front suspension 3 and the rear suspension 4 respectively is expressed by Expression (1). In Equation (1), Ftv (s) and Z (s) are obtained by Laplace transform of Ftv (v) and Z, respectively, and s is a Laplace operator. Moreover, the arrow direction of FIG. 2 is represented as a positive direction.

C: damping coefficient of the absorber K _tz: Vehicle tire vertical stiffness K _tx: the vehicle longitudinal direction rigidity of the tire P _x: driving stiffness Z: vertical displacement of the unsprung gravity position X: longitudinal displacement W of the unsprung centroid position: vertical load m: unsprung weight I _t: tires and wheels of inertia moment r _0: tire dynamic load radius epsilon: [dynamic load radius (deflection tires) variation amount] / [(deflection tires) static load radius variation amount]
V ₀ : Vehicle speed

On the other hand, when the front suspension 3 and the rear suspension 4 are moved up and down, the longitudinal force generated by the absorber 8 (attenuation main axis B _f ) and the absorber 13 (attenuation main axis B _r ) is defined as Fkz. When the specifications of the suspension 1 are as follows, the longitudinal force Fkz generated by the absorber 8 (attenuation main axis B _f ) and the absorber 13 (attenuation main axis B _r ) is expressed by Expression (2). In Equation (2), Fkz is a Laplace transform of Fkz (s).

C: Absorber damping coefficient α: Decay main shaft forward tilt angle (angle at which the absorber (damping main shaft B) tilts forward of the vehicle with respect to the vertical line E in the vehicle side view)
β: Diagonal angle on the front-rear elastic main axis (angle at which the front-rear elastic main axis A tilts upward with respect to the horizontal line D in the vehicle side view)
K _θ : Windup rigidity (rigidity when axle carrier (not shown) rotates around the spindle axis)
K _x : Front / rear elastic main shaft rigidity H: Amount of deviation in the vehicle vertical direction between the unsprung center of gravity position and the front / rear elastic main shaft A L: Amount of deviation in the vehicle front / rear direction between the unsprung center of gravity position and the damping main axis B

Further, when the front suspension 3 and the rear suspension 4 are vertically stroked, the longitudinal force generated by the longitudinal elastic main axis A _f (arm 7 and compliance bush 10) and the longitudinal elastic main axis A _r (arm 12 and compliance bush 15) is generated. Assuming Fkx, this longitudinal force Fkx is expressed by equation (3). In Equation (3), Fkx (s) is a Laplace transform of Fkx.

Then, the longitudinal force Fx input to the front suspension 3 and the rear suspension 4 is expressed by Expression (4).

When the longitudinal force Fx input to the front suspension 3 is the longitudinal force Fxf and the longitudinal force Fx input to the rear suspension 4 is the longitudinal force Fxr, the longitudinal force Fxf and the longitudinal force Fxr are canceled out. A front suspension 3 and a rear suspension 4 are set. In other words,
Fxr = −Fxf (5)
Attenuating main shaft forward tilt angles α _f , α _r , longitudinal elastic main shaft anti- _reverse angles β _f , β _r , windup stiffness K _θf , K _θr , longitudinal elastic main shaft stiffness K _xf , K _xr , absorber damping coefficient C _f , C _r , vehicle vertical displacements H _f , H _r between the unsprung center of gravity position and the longitudinal elastic main axes A _f , A _r, and the vehicle longitudinal direction between the unsprung center of gravity position and the damping main axes B _f , B _r The shift amounts L _f and L _r are determined, and the front suspension 3 and the rear suspension 4 are set based on the calculated values.

  By the way, the longitudinal force Ftv (v) input from each tire is a function that varies depending on the vehicle speed (v), and is a value that is determined almost uniquely when the vehicle speed, unsprung weight, tire specifications, and the like are determined. Therefore, the front suspension 3 and the rear suspension 4 may be set by obtaining the above values using a vehicle speed condition with a high use frequency and a ride weight condition with a high use frequency.

  Thus, according to the suspension 1 according to the first embodiment, the front suspension 3 and the front / rear force Fxf input to the front suspension 3 and the front / rear force Fxr input to the rear suspension 4 are canceled out. Since the rear suspension 4 is set, the longitudinal force Fx input from the tire can be reduced as a whole vehicle. In addition, since the front suspension 3 and the rear suspension 4 are set in consideration of the arrangement, rigidity, and damping coefficient of the absorbers 8 and 13, the longitudinal force Fx input from the tire is reduced with higher accuracy as a whole vehicle. It is possible to improve the riding comfort of the vehicle by suppressing the vibration in the vehicle longitudinal direction under the spring.

  And by setting the suspension 1 using the vehicle speed condition with high use frequency and the riding weight condition with high use frequency, the longitudinal force Ftv (v) input from the tire to the unsprung state can be more efficiently reduced. it can.

[Second Embodiment]
Next, the suspension 31 according to the second embodiment will be described with reference to FIGS. 6 and 7 as well. FIG. 6 is a diagram illustrating a functional configuration of the suspension according to the second embodiment.

  The suspension 31 further includes a vehicle speed sensor 32 and an ECU 33 that controls the change of the arrangement of the rear suspension 4 in the suspension 1 according to the first embodiment.

  The vehicle speed sensor 32 is a sensor that detects the traveling speed of the vehicle 2. The vehicle speed sensor 32 detects the vehicle speed by detecting the rotational speed of each wheel, and transmits the detected vehicle speed to the ECU 33 as a vehicle speed signal.

  The ECU 33 determines the arrangement, rigidity, and damping force (hereinafter referred to as “arrangement etc.”) of the rear suspension 4 so that the longitudinal force Fxf input to the front suspension 3 and the longitudinal force Fxr input to the rear suspension 4 are canceled out. To change). The ECU 33 is connected to a vehicle speed sensor 32, a longitudinal elastic main shaft arrangement changing device 16, a front and rear elastic main shaft rigidity changing device 20, a damping main shaft arrangement changing device 25, and a damping coefficient changing device 26. The ECU 33 controls the longitudinal elastic main shaft arrangement changing device 16, the front and rear elastic main shaft rigidity changing device 20, the damping main shaft arrangement changing device 25, and the damping coefficient changing device 26 based on the vehicle speed detected by the vehicle speed sensor 32. The arrangement of the rear suspension 4 is changed. The ECU 33 is mainly configured by a computer including a CPU, a ROM, and a RAM, for example.

  Next, the setting operation of the suspension 31 by the ECU 33 will be described with reference to FIG. FIG. 7 is a flowchart showing the suspension setting operation by the ECU.

First, the ECU 33 acquires the vehicle speed detected by the vehicle speed sensor 32 (step S1). Next, the ECU 33 calculates the phase ω _f of the longitudinal force Fxf generated by the front suspension 3 based on the vehicle speed acquired in step S1 using the above formula (4) (step S2), and the rear tire for the front tire 6 11 calculates the phase delay ω _z of the road surface displacement (step S3).

Next, the ECU 33 calculates a target phase ω _r at which the longitudinal force is input to the rear suspension 4 based on the phase ω _f calculated in step S2 and the phase ω _z calculated in step S3 (step S4). In step S4, the target phase ωr can be obtained by ωr = −ωf + ωz.

Meanwhile, ECU 33, using the above equation (4), calculates the gain _{G f} of the longitudinal force Fxf for the front suspension 3 is generated, the longitudinal force Fxf, the target gain _{G r} to generate the rear suspension 4 ( Step S5).

Then, ECU 33 is at the target phase omega _r calculated in step S4, so that the target gain _{G r} calculated in step S5, and calculates the longitudinal force Fxr to be generated in the rear suspension 4 (step S6). Then, the ECU 33 uses the formula (4) based on the longitudinal force Fxr calculated in step S6 to arrange the rear suspension 4, etc., that is, the damping main shaft forward tilt angle α _r , the front and rear elastic main shaft upper angle. beta _r, windup rigidity K _{[theta] r,} front and rear elastic principal axis stiffness K _xr, damping coefficient of the absorber C _r, in the vehicle vertical direction between the unsprung gravity center position and the longitudinal elastic main axis a _r shift amount H _r, and unsprung center of gravity position And a deviation _Lr in the vehicle front-rear direction between the main shaft _Br and the damping main shaft _Br are calculated (step S7).

  Thereafter, when the arrangement of the rear suspension 4 and the like are obtained in this way, the ECU 33 causes the front / rear elastic main shaft arrangement changing device 16, the front / rear elastic main shaft rigidity changing device 20, the damping main shaft arrangement changing device 25, and the damping coefficient changing device 26. By appropriately controlling, the setting is changed so that the arrangement or the like of the rear suspension 4 becomes the arrangement calculated in Step S7 (Step S8).

  Thus, according to the suspension 31 according to the second embodiment, the longitudinal force Fxf input to the front suspension 3 is canceled by the longitudinal force Fxr generated by the rear suspension 4 even when the vehicle speed changes. In addition, since the setting of the rear suspension 4 is appropriately changed, the longitudinal force Fx input from the tire can be reduced as a whole vehicle regardless of the change in the vehicle speed. In addition, since the arrangement of the rear suspension 4 and the like is calculated using the equation (4) including the arrangement of the absorbers 8 and 13, the longitudinal force Fx input from the tire as a whole vehicle is reduced with higher accuracy. Can do. As a result, it is possible to improve the ride comfort of the vehicle by suppressing the unsprung vehicle longitudinal vibration.

By longitudinal principal elastic axis the adjustment apparatus 16 by moving the arm 12, the front and rear principal elastic axis dihedral beta _r, and, in the vertical direction of the vehicle unsprung centroid position and front and rear elastic main axis A _r of the shift amount H _r The setting can be changed and the absorber 13 is moved by the damping spindle arrangement changing device 25, whereby the damping spindle forward tilt angle α _r and the deviation L in the vehicle front-rear direction between the unsprung center of gravity position and the damping spindle B _r are obtained. The setting of _r can be changed.

  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 above-described embodiment, the suspension is described as being configured by one arm. However, the number of arms and the type of suspension are not particularly limited. For example, a double wishbone type suspension or a multilink type is used. A suspension type such as a suspension may be used.

  Further, in the second embodiment, it has been described that only the arrangement or the like of the rear suspension 4 is changed. However, the arrangement or the like of the front suspension 3 may be changed, and the front suspension 3 and the rear suspension 4 may be changed. You may make it change setting of both arrangement | positioning.

It is the figure which showed typically the vehicle to which the suspension which concerns on embodiment is applied. This is for explaining the arrangement of the suspension. It is the figure which showed the relationship between a compliance bush and an arm, (a) shows the case where the inclination angle of an arm is large, (b) shows the case where the inclination angle of an arm is small. It is the figure which showed the example of a connection of the front-back elastic principal axis and a hub. It is the figure which showed the example of a connection of a damping main axis and a hub. It is the figure which showed the function structure of the suspension which concerns on 2nd Embodiment. It is the flowchart which showed the setting operation of the suspension by ECU.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Suspension, 2 ... Vehicle, 3 ... Front suspension, 4 ... Rear suspension, 5 ... Vehicle body, 7, 12 ... Arm (arm member), 8, 13 ... Absorber (attenuator), 9, 14 ... Spindle shaft, 10 , 15 ... Compliance bush (arm member), 16 ... Front / rear elastic main shaft arrangement changing device (arm member arrangement changing means), 20 ... Front / rear elastic main shaft rigidity changing device, 25 ... Damping main shaft arrangement changing device (attenuator is position changing means) , 26 ... damping coefficient changing device, 32 ... vehicle speed sensor, 33 ... ECU (setting changing means), C ... damping coefficient, K _x ... front and rear elastic main shaft rigidity (arm member rigidity), K _θ ... windup rigidity (spindle shaft) Rigidity around the vehicle), α ... Attenuation main axis forward tilt angle (inclination angle made by the attenuator with respect to the vehicle vertical direction line), β ... A front / rear elastic main axis anti-angle (with respect to the vehicle longitudinal direction line) H is the opposite angle formed by the axis in the direction in which the rigidity of the arm member acts), H is the amount of deviation in the vehicle vertical direction between the unsprung center of gravity position and the axis in the direction in which the rigidity of the arm member acts, and L is the unsprung center of gravity. The amount of deviation in the vehicle longitudinal direction between the position and the axis in the direction in which the damping force of the attenuator acts.

Claims (3)

In a suspension including an arm member that extends in the vehicle longitudinal direction and is disposed between the vehicle body and the spindle shaft, and an attenuator that extends in the vehicle vertical direction and is disposed between the vehicle body and the spindle shaft,
When the unsprung strokes up and down, the rigidity of the arm member, the rigidity around the spindle axis, the attenuation coefficient of the attenuator, the inclination angle formed by the attenuator with respect to the vehicle vertical direction line, the vehicle longitudinal direction line The angle between the axis in the direction in which the rigidity of the arm member acts, the amount of deviation in the vehicle vertical direction between the unsprung center of gravity position and the axis in the direction in which the rigidity of the arm member acts, and the unsprung center of gravity. The front-rear force input to the front suspension and the front-rear force input to the rear suspension, which are calculated based on the amount of displacement in the vehicle front-rear direction from the position and the axis in the direction in which the damping force of the attenuator acts, cancel each other. as such, the rigidity of the arm member, the spindle axis of the rigid damping coefficient of the damper, the inclination angle of the attenuator with respect to the vehicle vertical direction of the line, the arm member with respect to the vehicle longitudinal direction of the line The opposite angle formed by the axis in the direction in which the rigidity acts, the amount of deviation in the vertical direction of the vehicle between the unsprung center of gravity and the axis in the direction in which the arm member acts, and the unsprung center of gravity and the attenuation of the attenuator A suspension characterized in that an amount of deviation in a vehicle longitudinal direction from an axis in a direction in which a force acts is set. In a suspension including an arm member that extends in the vehicle longitudinal direction and is disposed between the vehicle body and the spindle shaft, and an attenuator that extends in the vehicle vertical direction and is disposed between the vehicle body and the spindle shaft,
Vehicle speed detection means for detecting the vehicle speed;
Setting changing means for changing the setting of the suspension;
With
When the unsprung strokes up and down according to the vehicle speed detected by the vehicle speed detecting means, the setting changing means includes a rigidity of the arm member, a rigidity around the spindle axis, a damping coefficient of the attenuator, a vehicle The inclination angle formed by the attenuator with respect to the line in the vertical direction, the opposite angle formed by the axis in the direction in which the rigidity of the arm member acts on the line in the vehicle longitudinal direction, the position of the center of gravity under the spring and the rigidity of the arm member The front suspension is calculated based on the amount of deviation in the vehicle vertical direction from the axis in the acting direction and the amount of deviation in the vehicle longitudinal direction from the position of the unsprung center of gravity and the axis in the direction in which the damping force of the attenuator acts. as the longitudinal force is canceled is inputted to the longitudinal force and the rear suspension to be input, the rigidity of the arm member, the spindle axis of the rigid damping coefficient of the damper versus the vehicle vertical direction of the line The angle formed by the attenuator, the opposite angle formed by the axis in the direction in which the rigidity of the arm member acts with respect to the vehicle longitudinal direction line, the position of the unsprung center of gravity, and the axis in the direction in which the rigidity of the arm member acts The suspension is characterized in that the displacement of the vehicle in the vertical direction and the setting of the displacement in the vehicle longitudinal direction between the unsprung center of gravity position and the axis in the direction in which the damping force of the attenuator acts are changed. Arm member arrangement changing means for changing the arrangement of the arm members;
Attenuator arrangement changing means for changing the arrangement of the attenuator;
The suspension according to claim 2 , further comprising:

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