JP6136563B2 - Vehicle suspension system - Google Patents

Description

The present invention is a vehicle suspension system, in particular, a suspension for supporting each wheel of the in-wheel motor vehicle (four-wheel vehicle front left and right wheels and left and right rear wheels are respectively provided an in-wheel motor) is provided with respective actuator The present invention also relates to a vehicle suspension system configured such that the kingpin offset of each wheel can be changed by the operation of each actuator.

  This type of vehicle suspension device is disclosed, for example, in Patent Document 1 below.

JP 2008-68832 A

  In the in-wheel motor vehicle described in Patent Document 1, the kingpin offset of each wheel is changed based on the vertical movement (change in wheel stroke) of each wheel when braking / driving force is applied to each wheel. It is set to improve the stability of the vehicle.

  By the way, in the in-wheel motor vehicle described in the above-mentioned Patent Document 1, depending on the traveling state of the vehicle (road surface condition, etc.), when the braking / driving force is applied to each wheel, the expected wheel stroke change is not necessarily performed. May not be obtained, in which case the intended kingpin offset change may not be obtained and the intended purpose may not be achieved. In the in-wheel motor vehicle described above, it is possible to improve the stability of the vehicle, but no consideration is given to improving the turning ability of the vehicle.

The present invention has been made to solve the above problems,
Front left and right and wheels and left and right rear wheels are provided with respective suspension for supporting each wheel of a four-wheel vehicle is provided with each an in-wheel motor is the actuator, the possible changes kingpin offset of the respective wheel by actuation of the actuators A vehicle suspension system configured;
Output detection means for detecting the output of each in-wheel motor;
An operation control means for controlling the operation of each actuator according to the output of each in-wheel motor detected by the output detection means;
The operation control means controls the operation of each actuator so that the kingpin offset of each wheel becomes an initial value when the output of each in-wheel motor is constant, and the output of each in-wheel motor changes. When the output changes, the kingpin offset of one of the left and right front wheels and the left and right rear wheel is changed from an initial value to a positive value, and the other kingpin offset of the left and right front wheels and the left and right rear wheels is The operation of each actuator is set so as to be changed from an initial value to a negative value .

  In the vehicle suspension system of the present invention, the kingpin offset can be changed in accordance with the output of the in-wheel motor, so that the desired kingpin offset change can be obtained regardless of the road surface condition. In the present invention, for example, the initial value of each kingpin offset when the output (motor torque) of each in-wheel motor of the left and right front wheels and the left and right rear wheels in the in-wheel motor vehicle is constant (during constant speed travel). When the output of each in-wheel motor on the left and right front wheels and the left and right rear wheels increases and changes (during acceleration), the kingpin offsets on the left and right front wheels change from initial values to positive (outside the vehicle). It is possible to set so that each kingpin offset of the left and right rear wheels is changed from the initial value to negative (inward of the vehicle).

  In this case, when the vehicle is traveling at a constant speed, torque steer due to a difference in output (motor torque) between the left and right wheels can be prevented, and the stability of the vehicle can be improved. In addition, during acceleration of the vehicle, it is possible to improve the stability of the vehicle by using the moment about the kingpin axis at the left and right front wheels as the toe-out moment and the moment about the kingpin axis at the left and right rear wheels as the toe-in moment. is there.

  In the vehicle suspension device of the present invention, for example, the initial value of each kingpin offset when the outputs (motor torques) of the in-wheel motors of the left and right front wheels and the left and right rear wheels is constant is set to zero. When the output of each in-wheel motor of the wheel and the left and right rear wheels increases and changes, the king pin offset of the left and right front wheels is changed from the initial value to negative, and the king pin offset of the left and right rear wheels is changed from the initial value to positive. It is possible to set so that.

  In this case, when the vehicle is traveling at a constant speed, torque steer due to a difference in output (motor torque) between the left and right wheels can be prevented, and the stability of the vehicle can be improved. In addition, during acceleration of the vehicle, it is possible to improve the turning performance of the vehicle by using the moment about the kingpin axis at the front left and right wheels as the toe-in moment and the moment about the kingpin axis at the left and right rear wheels as the toe-out moment. is there.

  In the vehicle suspension system of the present invention, the initial value of each kingpin offset when the output (motor torque) of each in-wheel motor of the left and right front wheels and the left and right rear wheels is constant can be set to other than zero. It is. In addition, when the output of each in-wheel motor on the left and right front wheels and the left and right rear wheels decreases and changes (during deceleration), the kingpin offset of each left and right front wheel is changed from the initial value to positive or negative, It is also possible to set each kingpin offset to be changed from the initial value to negative or positive.

In implementing the present invention described above, the suspension includes a suspension arm having a joint portion connected to a wheel support member that rotatably supports the wheel, and the actuator can change the position of the joint portion. It is also possible to be configured. In this case, the suspension mechanism described in the above-mentioned Patent Document 1 (the suspension arm that is a constituent member of the lower arm or the upper arm is configured to be extendable (the length can be changed), and the actuator is the length of the suspension arm. It is also possible to implement using a suspension mechanism that can change the position of the joint part by changing.

  The suspension arm (a suspension arm that is a constituent member of a lower arm or an upper arm that supports the wheel support member and has a joint portion connected to the wheel support member) is configured by a pair of front and rear. The intermediate portion of one of the suspension arms and the wheel support member are connected by a control arm, and the actuator changes the length of the control arm, thereby connecting the suspension arm and the wheel support member. It is also possible to change the position of the joint part. In this case, it is possible to change the kingpin offset by changing the position of the joint portion. In this case, it can be carried out without changing the length of the suspension arm. For this reason, it is possible to ensure the rigidity of the suspension arm while reducing the size and weight of the suspension arm.

1 is a schematic diagram schematically showing a configuration of a four-wheel vehicle to which the present invention is applicable. It is a perspective view which shows roughly the structure of the suspension applied to the right front wheel of the vehicle shown in FIG. 1, and the same wheel. FIG. 3 is a plan view schematically showing a configuration of a lower arm of the suspension shown in FIG. 2 and a control arm applied to the lower arm. FIG. 4 is a plan view schematically showing an operating state of the configuration shown in FIG. 3. 2 is a rear view schematically showing a relationship between a kingpin shaft constituted by a lower arm and an upper arm of the suspension shown in FIG. 2 and a kingpin shaft when the lower arm shown in FIG. 2 operates like the lower arm shown in FIG. It is. FIG. 5 is a front view schematically showing a configuration of an actuator that extends and contracts the control arm shown in FIGS. 3 and 4.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the configuration of a four-wheel vehicle V1 to which the present invention can be applied. In the four-wheel vehicle V1 of this embodiment, left and right front wheels 11 and 12 and left and right rear wheels 13 and 14 are in-wheel motors. 15, 16, 17 and 18 are provided. In each of the wheels 11, 12, 13, and 14, the wheel 12 is supported by the suspension 20 as shown in FIG.

  As shown in FIG. 1, each in-wheel motor 15, 16, 17, 18 is connected to a power storage device 40 and an electric control device (ECU) 50 via an inverter 30, and the electric control device (ECU). 50, the output (motor torque) is controlled in accordance with the amount of depression of an accelerator pedal (not shown). The electric control unit (ECU) 50 can detect the outputs (motor torques) of the in-wheel motors 15, 16, 17, 18. The electric control unit (ECU) 50 can detect the in-wheel motors 15, 16, 17, It also functions as output detection means for detecting 18 outputs.

  The suspension 20 shown in FIG. 2 is a double wishbone type suspension, and includes an upper arm 21 and a pair of front and rear lower arms 22 and 23 and a tie rod (torcon arm) 24. The upper arm 21 is connected to the vehicle body (not shown) at the vehicle inner ends 21a1 and 21a2, and is connected to the carrier 11a (see FIG. 3) at the vehicle outer end 21b (joint portion). The carrier 11 a is a wheel support member that is supported by the upper arm 21, the lower arms 22, 23, and the like and rotatably supports the wheel 12, and an upper portion thereof is connected to the vehicle outer end 21 b (joint portion).

  As shown in FIGS. 2 and 3, the lower arm 22 is a front lower arm (lower No. 1 arm), is connected to a vehicle body (not shown) at a vehicle inner end 22a, and is carriered at a vehicle outer end 22b (joint portion). It is connected to the lower part of 11a. As shown in FIGS. 2 and 3, the lower arm 23 is a rear lower arm (lower No. 2 arm), is connected to the vehicle body (not shown) at the vehicle inner end 23a, and is carrier at the vehicle outer end 23b (joint portion). It is connected to the lower part of 11a. As shown in FIG. 2, the tie rod (torcon arm) 24 is connected to the vehicle body (not shown) at the vehicle inner end 24a, and is connected to the carrier 11a at the vehicle outer end 24b (joint portion).

  In the suspension 20 shown in FIG. 2 to FIG. 5, the line connecting the vehicle outer end 21b of the upper arm 21 and the intersection point X of the lower arms 22 and 23 (intersection point of the lower double joint arm) is the virtual kingpin axis Lo, and the kingpin offset Is Ko, and the driving force (Fd) / braking force (Fb) of the in-wheel motor 16 acting on the suspension 20 acts on the contact surface with the road surface of the tire. For this reason, when the wheel 12 is driven by the in-wheel motor 16, driving torque (Md = Fd × Ko) is generated around the virtual kingpin axis Lo, and the wheel 12 is braked (regenerative braking) by the in-wheel motor 16. Sometimes, braking torque (Mb = Fb × Ko) is generated around the virtual kingpin axis Lo.

  By the way, in the suspension 20 of this embodiment, as shown in FIGS. 3 and 4, the intermediate portion of the lower arm 22 and the carrier 11 a are connected by the kingpin control arm 25, and the actuator 60 has the length of the kingpin control arm 25. , The coupling angle between the lower arm 22 and the carrier 11a and the coupling angle between the lower arm 23 and the carrier 11a are changed (the trapezoidal shape formed by the carrier 11a and the lower arms 22, 23, etc. is changed) The positions of the vehicle outer ends 22b and 23b (joint portions) of the lower arms 22 and 23 can be changed. As a result, the intersection X of the lower arms 22 and 23 can be moved as shown in FIGS. 4 and 5, and the kingpin offset Ko of the wheel 12 can be changed from the initial value.

  As shown in FIG. 6, the kingpin control arm 25 includes an extendable ball screw portion 25 a, an arm side joint portion 25 b, and a carrier side pillow ball portion 25 c. The actuator 60 extends and contracts the ball screw portion 25 a. It is possible to change the length. As shown in FIGS. 3 and 4, the actuator 60 can change the position of the joint portions (22b, 23b) connected to the carrier 11a by expanding and contracting the kingpin control arm 25 and actuates its operation. It is configured to be controlled by the control device 70.

  The operation control device 70 is an operation control means for controlling the operation of the actuator 60, and is connected to an electric control device (ECU) 50 as shown in FIGS. When it is constant, the operation of the actuator 60 is controlled so that the kingpin offset Ko of the wheel 12 becomes the initial value. When the output of the in-wheel motor 16 changes, the kingpin offset Ko of the wheel 12 changes from the initial value according to the output change. It is set to control the operation of the actuator 60 to be changed.

  In the vehicle suspension system of the above-described embodiment, the kingpin offset (Ko) can be changed according to the output of each in-wheel motor (16). It is possible to obtain. Further, in the vehicle suspension device of this embodiment, for example, the in-wheel motors 15, 16, 17, and the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 in the four-wheel vehicle V1 (in-wheel motor vehicle). The initial value of each kingpin offset Ko when the output (motor torque) 18 is constant (during constant speed running) is set to zero, and the in-wheel motors 15 of the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14 are set. , 16, 17, and 18 when the output of the left and right front wheels 11 and 12 is changed from the initial value to positive (outside the vehicle) when the output of the left and right rear wheels 13 and 12 is increased. Each of the 14 kingpin offsets Ko can be set to be changed from the initial value to negative (inward of the vehicle).

  In this case, when the vehicle V1 travels at a constant speed, torque steer due to the output (motor torque) difference between the left and right wheels 11, 12, 13 and 14 can be prevented, and the stability of the vehicle V1 can be improved. It is possible to plan. Further, when the vehicle V1 is accelerated, the moment about the kingpin axis at the left and right front wheels 11 and 12 is used as a toe-out moment, and the moment about the kingpin axis at the left and right rear wheels 13 and 14 is used as a toe-in moment. It is possible to improve.

  In the vehicle suspension device of this embodiment, for example, when the outputs (motor torques) of the in-wheel motors 15, 16, 17, 18 of the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 are constant. The left and right front wheels when the initial value of each kingpin offset Ko is zero and the outputs of the in-wheel motors 15, 16, 17, and 18 of the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 increase. Each kingpin offset Ko of 11 and 12 can be changed from the initial value to negative, and each kingpin offset Ko of the left and right rear wheels 13 and 14 can be set to change from the initial value to positive.

  In this case, when the vehicle V1 travels at a constant speed, torque steer due to the output (motor torque) difference between the left and right wheels 11, 12, 13 and 14 can be prevented, and the stability of the vehicle V1 can be improved. It is possible to plan. Further, when the vehicle V1 is accelerated, the moment around the kingpin axis at the left and right front wheels 11 and 12 is set as a toe-in moment, and the moment around the kingpin axis at the left and right rear wheels 13 and 14 is set as a toe-out moment. It is possible to improve the performance.

  In the implementation of the above-described embodiment, each kingpin offset when the outputs (motor torques) of the in-wheel motors 15, 16, 17, 18 of the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 are constant. It is also possible to set the initial value of Ko to a value other than zero. In this case, if there is a difference in output (motor torque) between the left and right wheels, the torque steer due to the difference in output (motor torque) between the left and right wheels can be achieved by setting each kingpin offset Ko to zero. Can be prevented. Moreover, when carrying out the above-described embodiment, the left and right front wheels 11 and 12 when the outputs of the in-wheel motors 15, 16, 17 and 18 of the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14 decrease and change. It is also possible to set each kingpin offset Ko to be positive or negative from the initial value and to change each kingpin offset Ko of the left and right rear wheels 13 and 14 from the initial value to negative or positive.

  Further, in the vehicle suspension device of the above-described embodiment, the lower arm of the suspension 20 that supports the wheel 12 is composed of a pair of front and rear, and the intermediate portion of one lower arm 22 and the carrier (wheel support member) 11a are the kingpin control arm. 25, the actuator 60 changes the length of the kingpin control arm 25, thereby changing the connection angle between the lower arm 22 and the carrier 11a and the connection angle between the lower arm 23 and the carrier 11a. The positions of the vehicle outer ends (joint portions) 22b and 23b of the vehicle 23 can be changed. For this reason, it is possible to change the kingpin offset Ko by changing the positions of the vehicle outer ends (joint portions) 22b and 23b. In this case, the suspension arm (the upper arm 21 and the lower arms 22 and 23) can be implemented without changing the length. Therefore, it is possible to ensure the rigidity of the suspension arms (upper arm 21 and lower arms 22, 23) while reducing the size and weight of the suspension arms (upper arm 21 and lower arms 22, 23).

  In the vehicle suspension device according to the above-described embodiment, a configuration in which the intermediate portion of the front lower arm 22 and the carrier 11a are connected by the kingpin control arm 25 is adopted. However, the intermediate portion of the rear lower arm 23 and the carrier 11a are It is also possible to implement by adopting a configuration connected by the kingpin control arm 25. In addition, when the upper arm (21) is configured by a pair of front and rear, it is possible to implement by adopting a configuration in which the intermediate part of one of the upper arms and the carrier are connected by the kingpin control arm (25). is there.

  Further, in the vehicle suspension device of the above-described embodiment, a double wishbone type suspension is adopted as the suspension, but the type of suspension to be adopted can be changed as appropriate, such as a strut suspension or a multilink. The present invention can also be implemented in a vehicle suspension device that employs a suspension of the type.

DESCRIPTION OF SYMBOLS 11, 12, 13, 14 ... Wheel, 11a ... Carrier (wheel support member), 15, 16, 17, 18 ... In-wheel motor, 20 ... Suspension, 21 ... Upper arm, 21a1, 21a2 ... Car inner end, 21b ... Car outer end (Joint part), 22, 23 ... lower arm, 22a, 23a ... inner end, 22b, 23b ... outer end (joint part), 24 ... tie rod (torcon arm), 25 ... kingpin control arm (control arm), 30 ... inverter 40 ... electric storage device, 50 ... electric control device (output detection means), 60 ... actuator, 70 ... operation control device (operation control means), V1 ... four-wheel vehicle

Claims (3)

Front left and right and wheels and left and right rear wheels are provided with respective suspension for supporting each wheel of a four-wheel vehicle is provided with each an in-wheel motor is the actuator, the possible changes kingpin offset of the respective wheel by actuation of the actuators A vehicle suspension system configured;
Output detection means for detecting the output of each in-wheel motor;
An operation control means for controlling the operation of each actuator according to the output of each in-wheel motor detected by the output detection means;
The operation control means controls the operation of each actuator so that the kingpin offset of each wheel becomes an initial value when the output of each in-wheel motor is constant, and the output of each in-wheel motor changes. When the output changes, the kingpin offset of one of the left and right front wheels and the left and right rear wheel is changed from an initial value to a positive value, and the other kingpin offset of the left and right front wheels and the left and right rear wheels is A vehicle suspension system configured to control the operation of each actuator so as to be changed from an initial value to a negative value . The vehicle suspension device according to claim 1,
The suspension includes a suspension arm having a joint portion connected to a wheel support member that rotatably supports the wheel, and the actuator is configured to be capable of changing a position of the joint portion. apparatus. The vehicle suspension device according to claim 2,
The suspension arm is composed of a pair of front and rear, the intermediate portion of one of the suspension arms and the wheel support member are connected by a control arm, and the actuator changes the length of the control arm. The suspension system for a vehicle is configured such that a connection angle between the suspension arm and the wheel support member is changed so that the position of the joint portion can be changed.

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