JP2017088060A - Suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension device capable of suppressing deterioration in ride comfort and steering stability when all motors fail even in a vehicle in which wheels are individually driven by a motor. A vehicle body B of a vehicle V and left and right front and rear wheels W1, W2, which have left and right front and rear wheels W1, W2, W3 and W4 that are individually driven by a motor and whose vehicle body posture is controlled by torque control of the motor. Suspension springs interposed between W3 and W4 are provided, and the suspension springs are the laminated leaf springs 1 and 2. [Selection] Figure 1

Description

  The present invention relates to a suspension device.

  Conventionally, there is a vehicle in which wheels are individually driven by a motor such as an in-wheel motor (IWM). Among such in-wheel motor vehicles, there is one in which the braking / driving force of each wheel is individually controlled by controlling the torque of the motor to suppress vehicle pitch, bounce, and roll (for example, Patent Documents 1, 2, and 3). In the vehicle, as long as the motor operates normally based on the control command and the braking / driving force of all the wheels can be individually controlled, there is no problem even if a damper for exhibiting the damping force is not installed.

JP 2007-118898 A JP 2005-225373 A JP 2006-109642 A

  However, if all the dampers are removed, the braking / driving force of all wheels cannot be controlled due to the failure of all motors M (hereinafter referred to as the failure of all motors). At the same time, the damping function for suppressing the loss is lost. Therefore, when all the dampers are eliminated, the riding comfort when the vehicle is retracted to the road shoulder or the roadside belt when all the motors fail is significantly deteriorated and the steering stability is lowered. On the other hand, in the unlikely event that all the motors fail, it would be costly to provide a damper on each wheel as in a conventional engine-driven vehicle.

  Accordingly, the present invention provides a suspension device that can suppress the deterioration of ride comfort and steering stability when all the motors fail, and can reduce costs when mounted on a vehicle in which wheels are individually driven by a motor. Objective.

  The invention according to claim 1, which solves the above problem, includes a suspension spring interposed between the vehicle body and the wheel of which the vehicle body posture is controlled by torque control of a motor that individually drives the wheel. The suspension spring is a laminated leaf spring. For this reason, vehicle body vibration can be suppressed without providing a damper separately from the suspension spring.

  According to a second aspect of the present invention, in addition to the configuration according to the first aspect, the overlap leaf spring is connected to the axle of the wheel arranged at both ends on both sides, and supports the vehicle body at a central portion. For this reason, since the both ends of a laminated leaf spring function also as an arm which supports a wheel so that vertical movement is possible, the number of parts can be reduced.

  According to the suspension device of the present invention, even in a vehicle in which wheels are individually driven by a motor, it is possible to suppress deterioration in ride comfort and steering stability when all motors fail, and to reduce costs.

(A) is the top view which showed schematically the attachment state of the suspension apparatus which concerns on one embodiment of this invention, (b) is the front view of (a). It is a front view which shows the laminated leaf | plate spring of the suspension apparatus which concerns on one embodiment of this invention. (A) is the top view which showed schematically the attachment state of the modification of the suspension apparatus which concerns on one embodiment of this invention, (b) is a front view of (a).

  Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts. Suspension devices S1, S2 according to the embodiment of the present invention shown in FIGS. Hereinafter, the front, rear, left and right of the vehicle V viewed from the driver who drives the vehicle V and the suspension devices S1, S2 mounted on the vehicle V are simply “front”, “rear”, “left”, “unless otherwise stated”. "Right".

  As shown in FIG. 1A, a vehicle V on which a suspension device S1 according to an embodiment of the present invention is mounted includes a vehicle body B, a left front wheel W1, a right front wheel W2, a left rear wheel W3, and a right rear wheel. Four wheels of the wheel W4 and electric motors (not shown) attached to the left and right front and rear wheels W1, W2, W3, and W4 for braking and driving (braking and driving) the wheels, respectively, The suspension device S1 is interposed between W2, W3, W4 and the vehicle body B. In the automobile V, tie rods (not shown) are connected to the left and right front wheels W1, W2, and the direction is changed by changing the direction of the front wheels by a handle operation. That is, the left and right front wheels W1, W2 are steering wheels, and the left and right rear wheels W3, W4 are driven wheels.

  Subsequently, the motors that control and drive the wheels are in-wheel motors and are provided inside the hubs of the left and right front and rear wheels W1, W2, W3, and W4, respectively. Then, the motor torque is individually controlled to individually apply driving force to the left and right front and rear wheels W1, W2, W3, and W4. Further, the motor is operated as a generator to perform energy regeneration, and braking force based on regenerative braking can be individually applied to the left and right front and rear wheels W1, W2, W3, and W4. In addition, as long as one motor drives one wheel, the motor may be provided outside the wheel.

  The motor is connected to a control device (not shown), and the control device determines the state of the automobile V (for example, vertical acceleration on a spring, vertical acceleration on a spring, stroke of a suspension device, etc.). The optimum braking / driving force for suppressing vehicle body vibration is determined for each wheel from information obtained by various sensors (not shown) for detection, and the motor is controlled so that the braking / driving force of each wheel is optimized. Send each command. And by giving a driving force and a braking force to each wheel separately, the vertical vibration of the vehicle body B is suppressed, and a pitch, a bounce, a roll, etc. are prevented. The braking force applied to the wheels may be a disc brake or a drum brake, or may be a combination of these braking forces and a braking force based on regenerative braking.

  Subsequently, the suspension device S1 includes a laminated leaf spring 1 provided between the left and right front wheels W1, W2, and a laminated leaf spring 2 provided between the left and right rear wheels W3, W4. The laminated leaf springs 1 and 2 are also called leaf springs, and both have a plurality of leaf springs 3 that are vertically stacked and a clip 4 that bundles the leaf springs 3 as shown in FIG. And when it receives a load, the laminated leaf springs 1 and 2 will bend up and down (lamination direction), and will return to the original shape by the elasticity which leaf spring 3 itself has. Moreover, if the said laminated leaf | plate springs 1 and 2 deform | transform, the leaf | plate springs 3 will rub against each other and the heat by friction will arise. That is, the laminated leaf springs 1 and 2 function as springs that exhibit elastic force, and also function as dampers that convert the kinetic energy into thermal energy due to friction and exhibit a damping force that suppresses deformation of the leaf spring 3. To do.

  Further, as shown in FIG. 1B, the front leaf spring 1 extends in the vehicle width direction and both left and right ends are connected to the axles of the left and right front wheels W1 and W2, respectively. Is connected to the vehicle body B. The rear leaf spring 2 also extends in the vehicle width direction, and both left and right ends are connected to the axles of the left and right rear wheels W3 and W4, respectively, and the central portion thereof is connected to the vehicle body B. Therefore, the laminated leaf springs 1 and 2 function as a suspension spring that elastically supports the vehicle body B at the center thereof, and also function as a damper, and exhibit a damping force that suppresses vertical vibration of the vehicle body B. Further, between the left and right front wheels W1 and W2 and the vehicle body B and between the left and right rear wheels W3 and W4 and the vehicle body B, there are provided arms 5 that respectively support the wheels so as to be movable up and down. An arm 5 is provided below the laminated leaf springs 1 and 2. As described above, since the laminated leaf springs 1 and 2 are deformed and bent up and down, the left and right end portions swing up and down. For this reason, both ends of the laminated leaf springs 1 and 2 function as the upper arm of the double wishbone suspension, and the arm 5 functions as the lower arm.

  Hereinafter, the operation of the suspension device S1 will be described.

  According to the suspension device S1, when an impact caused by road surface unevenness or the like is input to the left and right front and rear wheels W1, W2, W3, W4, the impact is absorbed by the overlap leaf springs 1 and 2, and the vehicle body B continues to shake. Is suppressed by the laminated leaf springs 1 and 2. For this reason, according to the automobile V in which the vehicle body posture is controlled by the torque control of the motor, the motor torque can be normally controlled and the braking / driving force of the wheel can be individually controlled. The damping force that suppresses the vertical vibration of the vehicle body B is exhibited both in the control of the braking / driving force.

  On the other hand, when the damping function that suppresses the vertical vibration of the vehicle body B by the control of the braking / driving force of the wheels is lost due to the failure of all the motors (when all the motors fail), The vertical vibration of the vehicle body B is suppressed only by the laminated leaf springs 1 and 2. Therefore, when the suspension device S1 is mounted on the vehicle V whose vehicle body posture is controlled by the motor torque control, even if the damping function for suppressing the vertical vibration of the vehicle body B by the control of the braking / driving force of the wheels is lost, It is possible to easily retreat the automobile V to the road shoulder or the roadside zone by suppressing a significant deterioration in the ride comfort of the automobile V and a decrease in steering stability when the motor fails.

  Hereinafter, the function and effect of the suspension device S1 will be described.

  Both ends of the laminated leaf spring 1 are connected to the axles of left and right front wheels (wheels arranged side by side) W1 and W2, and support the vehicle body B at the center. Similarly, the overlap leaf spring 2 is connected at both ends to the axles of the left and right rear wheels (wheels arranged side by side) W3 and W4, and supports the vehicle body B at the center. That is, the laminated leaf springs 1 and 2 extend in the vehicle width direction, the left and right wheels are connected to both ends thereof, and the center is supported by the vehicle body B. For this reason, both ends of the laminated leaf springs 1 and 2 can function as an upper arm of a double wishbone suspension. In addition, the left and right wheels can be supported by a single leaf spring 1 and 2 so that the left and right wheels can be moved up and down so that the left and right wheels can be supported by arms such as individual upper arms. The number can be reduced.

  The arrangement of the laminated leaf springs 1 and 2 is not limited to the above, and can be changed as appropriate. For example, like the suspension device S2 shown in FIGS. 3A and 3B, the overlap leaf springs 6 may be interposed between the left and right front and rear wheels W1, W2, W3, and W4 and the vehicle body B, respectively. As shown in FIG. 3 (a), each of these leaf springs 6 extends in the longitudinal (front-rear) direction of the vehicle body B, supports the vehicle body B at both ends thereof, and a wheel axle is connected to the center portion thereof. It has come to be. Further, one of the left and right wheels on the front wheel side and the rear wheel side may be connected by the overlap leaf spring 1 (or 2), and the overlap leaf spring 6 may be attached to the other left and right wheels on the front wheel side and the rear wheel side. The laminated leaf springs 1 (or 2) and 6 may be used in combination.

  The suspension devices S1 and S2 have left and right front and rear wheels (wheels) W1, W2, W3, and W4 that are individually driven by a motor, and the vehicle body of the vehicle V whose body posture is controlled by torque control of the motor. A suspension spring interposed between B and the wheel is provided, and the suspension springs are the laminated leaf springs 1, 2, and 6.

  Here, in the case of a conventional suspension device, a telescopic type provided with a spring (suspension spring) such as a coil spring between a vehicle body and a wheel, and a damper (for example, an outer shell and a rod that goes in and out of the outer shell). A damper or a housing and a rotary damper or the like including a shaft inserted into the housing to rotate, and the vehicle body is elastically supported by the suspension spring and the vehicle body vibration is suppressed by the damper. According to the suspension devices S1 and S2, the overlapping leaf springs 1, 2, and 6 themselves that are suspension springs can exhibit a damping force, so that the conventional damper can be omitted. Therefore, according to the suspension devices S1 and S2, when the wheels are individually driven by a motor and mounted on a vehicle whose body posture is controlled by motor torque control, While suppressing the deterioration of steering stability, the cost can be reduced.

  Further, in the suspension devices S1 and S2, the suspension springs are all the laminated leaf springs 1, 2, and 6, and the vibrations of all the four wheels can be damped by the laminated leaf springs, so the cost reduction effect is high. However, a part of the plurality of suspension springs may be replaced with a laminated leaf spring, the damper of the part may be omitted, and both the suspension spring and the damper may be provided in the other part.

  In the present embodiment, the suspension devices S1 and S2 are mounted on the four-wheeled vehicle V, but may be mounted on any vehicle as long as the vehicle has two or more wheels.

  Although the preferred embodiments of the present invention have been described in detail above, modifications, changes and modifications can be made without departing from the scope of the claims.

B ... body, S1, S2 ... suspension device, V ... automobile (vehicle), W1 ... left front wheel (wheel), W2 ... right front wheel (wheel), W3 ... left rear Wheel (wheel), W4 ... Right rear wheel (wheel), 1, 2, 6 ... Lap leaf spring (suspension spring)

Claims (2)

Comprising two or more wheels that are individually driven by a motor, and a suspension spring interposed between the vehicle body and the wheels of which the vehicle body posture is controlled by torque control of the motor;
The suspension device, wherein the suspension spring is a laminated leaf spring. 2. The suspension device according to claim 1, wherein the overlap leaf spring is connected to an axle of the wheel that is aligned at both ends on the left and right sides, and supports the vehicle body at a central portion.

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