JPH10305720A - Stabilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high roll rigidity without sacrificing seating comfortableness by changing an apparent spring constant of a bar-shaped spring member to which a piezoelectric conversion element is stuck by changing impressed voltage on the piezoelectric conversion element by the bar-shaped spring member in which plate-shaped piezoelectric conversion elements are closely arranged at proper places. SOLUTION: Piezoelectric modules 4 are closely arranged on the outer peripheral surfaces of parts which are bent in an L-shape from the supporting point by left and right saddles 2 and are extended in the same direction. When a stabilizer rod 1 is going to bend at this stage, compressive stress is generated in the piezoelectric conversion elements(elements) of the piezoelectric modules 4 on a tensile side and tensile stress is generated in the elements on a compression side. Internal stress generated in the elements in this way acts in a direction that the bending of the rod 1 is suppressed and apparent rigidity of the rod 1 is increased. When voltage is impressed on the elements, inclinations are changed at the parts on which the elements are provided, the angle of torsion at the other end becomes the same as that of a conventional product which is large in spring constant and sufficient roll rigidity is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle stabilizer.

[0002]

2. Description of the Related Art Left and right suspension arms are interconnected via stabilizers in order to increase roll rigidity during turning. This stabilizer is mainly composed of a round bar, and suppresses uneven behavior of the left and right suspension arms by a spring force against torsion.

[0003]

However, in order to increase the roll rigidity of the vehicle, it is necessary to increase the spring constant of the stabilizer, but on the other hand, the increase in the diameter increases the weight. In addition, there has been a problem that the movement of the suspension arm is restrained more than necessary and the riding comfort is deteriorated.

[0004]

SUMMARY OF THE INVENTION In order to solve such a problem, a stabilizer capable of realizing high roll rigidity without increasing the weight or deteriorating the riding comfort is provided.
In the present invention, the configuration of the stabilizer includes a rod-shaped spring member in which a plate-shaped piezoelectric conversion element is closely arranged in a proper position, control means for controlling the amount of distortion of the piezoelectric conversion element, and detection means for detecting a running state of the vehicle. Then, in accordance with the running state of the vehicle detected by the detection means, an internal stress is generated in the piezoelectric transducer in a direction in which the elastic deformation of the rod-shaped spring member is restrained or promoted. According to this, by changing the voltage applied to the piezoelectric conversion element, the apparent spring constant of the rod-shaped spring member to which the piezoelectric conversion element is attached can be freely changed. And
By adjusting the apparent spring constant of this rod-shaped spring member to an appropriate value in accordance with the running state of the vehicle detected by the detection means, while achieving high roll rigidity during turning, riding comfort when traveling straight ahead is improved. It is possible to avoid the drop.

The piezoelectric transducers include PZT (zirconate titanate), PLZT (lanthanum zirconate titanate), and PMN (magnesium niobium lead oxide).
PVDF (polyvinylidene fluoride) and the like are used.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

FIG. 1 shows a stabilizer rod to which the present invention is applied. The stabilizer rod 1 has both ends connected to left and right suspension arms (not shown), and is fixed to the lower surface of a body frame (not shown) via a pair of saddles 2. The piezoelectric module 4 is closely arranged on the outer peripheral surface of a portion which is bent and extended in the same direction.

The piezoelectric module 4 generates a distortion according to an applied voltage. As shown in FIG.
And a pair of copper electrodes 6 provided on both front and back surfaces of the piezoelectric conversion element 5.
And an epoxy resin coating 8 integrated by thermocompression so as to cover these piezoelectric transducers 5 and copper electrodes 6.
And Further, as shown in FIG. 3, a conductive sheet 9 containing Ni is provided between the piezoelectric transducer 5 and the electrode 6.
0 is provided.

The piezoelectric module 4 configured as described above
Is actually attached to the stabilizer rod 1,
As shown in FIG. 4, the stabilizer rod 1 is formed into a circular arc shape along the outer peripheral surface of the round rod-shaped stabilizer rod 1, and is arranged so that the longitudinal direction is along the axial direction of the stabilizer rod 1.

As shown in FIG. 5, a pair of copper electrodes 6 of the piezoelectric module 4 are connected to the piezoelectric conversion element 5 via an amplifier 12.
Is connected to a controller 13 for controlling the amount of distortion. The controller 13 includes a sensor 14 for detecting a roll state of the vehicle body.
Is connected. As the sensor 14, an acceleration sensor that detects the acceleration in the lateral direction of the vehicle body, or a distortion sensor that directly detects the degree of twist of the stabilizer rod 1 is used. Further, a sensor that detects an amount that can indirectly determine the roll state of the vehicle body, such as the behavior of the suspension arm or the steering angle, may be used.

Next, the operation principle of the device of the present invention will be described.

When the left and right suspension arms operate unevenly due to the centrifugal force acting on the vehicle body during turning, external forces are applied to both ends of the stabilizer rod 1 connected to the suspension arm in the vertical direction, and the piezoelectric actuator 4 is actuated. Bending occurs in the provided portion extending in the front-rear direction.

On the other hand, when the sensor 14 detects the roll state of the vehicle body, a detection signal from the sensor 14 is input to the controller 13, and in accordance with the signal, the control voltage is transmitted from the controller 13 via the amplifier 12 to the piezoelectric conversion element. 5, a strain stress is generated in the piezoelectric conversion element 5.

For example, as shown in FIG. 6, when the stabilizer rod 1 tries to bend, the piezoelectric module 4 on the tension side
As shown by an arrow, a compressive stress is generated in the piezoelectric conversion element 5a, and a tensile stress is generated in the piezoelectric conversion element 5 of the piezoelectric module 4b on the compression side as shown by an arrow. When the stabilizer rod 1 bends in the opposite direction, tensile and compressive stresses opposite to those described above are generated in the piezoelectric modules 4a and 4b. The internal stress generated in the piezoelectric transducer 5 in this manner acts to suppress the deflection of the stabilizer rod 1, and as a result, the apparent rigidity of the stabilizer rod 1 increases.

FIG. 7 shows a twisted state from one end to the other end of the stabilizer rod 1 when an external force is input to both ends of the stabilizer rod 1. Since the stabilizer rod 1 has a small diameter and a small spring constant as compared with the conventional product, it exhibits a relatively large inclination and is greatly twisted when no voltage is applied to the piezoelectric transducer from the controller. On the other hand, when a voltage is applied to the piezoelectric conversion element from the controller, the inclination changes at the portion where the piezoelectric conversion element is provided, and as a result, the torsion angle at the other end is substantially the same as that of the conventional product having a large spring constant. This indicates that sufficient roll rigidity is secured.

In the above, an example has been described in which the bending that occurs in the portion of the stabilizer rod 1 extending in the front-rear direction is suppressed. However, the torsion that occurs in the portion of the stabilizer rod 1 that extends in the left-right direction is suppressed by the piezoelectric module 4. Can also be configured. In this case, as shown in FIG.
The piezoelectric module 4 with respect to the axis of the stabilizer rod 1
It is preferable to arrange the piezoelectric module 4 so that the center line is inclined. Thereby, as in the case of bending described above,
Since a stress is generated in the piezoelectric transducer 5 in a direction that restricts expansion and contraction distortion generated on the outer peripheral surface due to the twist of the stabilizer rod 1, torsional distortion of the stabilizer rod 1 is suppressed, and twisting of the stabilizer rod 1 is suppressed.

[0017]

As described above, according to the present invention, the apparent spring constant of the rod can be changed as required by changing the voltage applied to the piezoelectric transducer arranged on the rod. Thus, high roll stiffness can be achieved without sacrificing ride quality. further,
Since the piezoelectric conversion element can generate a large internal stress even if it is small and lightweight, it is possible to obtain an effect that the weight can be reduced as compared with the conventional rigidity enhancement by increasing the diameter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a stabilizer configured according to the present invention.

FIG. 2 is a perspective view showing a piezoelectric module.

FIG. 3 is a sectional view of the piezoelectric module shown in FIG. 2;

FIG. 4 is an essential part perspective view showing a state where the piezoelectric module shown in FIG. 2 is actually mounted on a stabilizer;

FIG. 5 is a block diagram showing a configuration example of control means of the piezoelectric module shown in FIG.

FIG. 6 is an essential part cross sectional view for explaining the operation principle of the piezoelectric module shown in FIG. 4;

FIG. 7 is a graph showing a twist angle along the length direction of the stabilizer;

FIG. 8 is an essential part perspective view showing a state where the piezoelectric module shown in FIG. 2 is mounted on a twisted portion of the stabilizer;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stabilizer rod 2 Saddle 4 Piezoelectric module 5 Piezoelectric conversion element 6 Copper electrode 8 Coating body 9 Conductive sheet 10 Polyimide film 12 Amplifier 13 Controller 14 Sensor

Claims (1)

[Claims] 1. A rod-shaped spring member in which piezoelectric transducers are closely arranged at appropriate positions, control means for controlling the amount of distortion of the piezoelectric transducers, and means for detecting a running state of a vehicle, wherein the detection means detects Depending on the running state of the vehicle
A stabilizer, wherein an internal stress is generated in the piezoelectric transducer in a direction in which the elastic deformation of the rod-shaped spring member is restricted or promoted.