JP2009227200A - Damper mount and damper mount control device of suspension for vehicle - Google Patents

Abstract

An object of the present invention is to make it possible to variably set a vibration damping characteristic of a damper mount and to ensure optimum riding comfort over a wide area.
A rubber bushing 41 disposed between a damper device 30 and a vehicle body 100 and having one side connected to the damper device 30 and the other side connected to the vehicle body 100 is elastically deformed by an actuator 60, and The apparent spring constant of the rubber bush 41 is changed.
[Selection] Figure 2

Description

  The present invention relates to a damper mount (strut mount) and a damper mount control device for a vehicle suspension, and more particularly to a damper mount and a damper mount control device including a rubber bush.

  A suspension of a vehicle such as an automobile includes a damper device having vibration damping capability. The damper device has a lower end portion connected to a wheel-supported suspension arm and an upper end portion connected to a vehicle body by a damper mount including a rubber bush (for example, Patent Document 1).

  The rubber bush is an anti-vibration rubber composed of a rubber-like elastic body, and the spring constant (reaction force characteristic) is uniquely determined by the rubber material, shape, and the like.

As a conventional technique, a polymer actuator is embedded in a rubber bush, and the apparent spring constant of the rubber bush is changed by driving the polymer actuator to expand and contract (for example, Patent Document 2).
JP 2007-290425 A JP 2005-127386 A

  Various proposals have been made to variably control the damping performance of the damper device according to the road surface condition and the vehicle speed by using a damper device having a variable damping capability. However, the damper device cannot effectively suppress the transmission of traveling vibration to the vehicle body due to its own friction and the like, and there is a region where the ride comfort cannot be improved. The rubber bush of the damper mount plays a role of suppressing such vibration transmission and improving ride comfort.

  The impact of the friction of the damper device on the ride comfort varies depending on the road surface condition and the vehicle speed, so if the damper mount characteristics are also variably set according to the road surface condition and the vehicle speed, vibration from the damper device It is possible to effectively suppress transmission to the vehicle body and further improve ride comfort.

  However, the rubber bush of the conventional damper mount has a spring constant that is uniquely determined by the rubber material, shape, etc., and does not have variable vibration isolation characteristics. For this reason, the conventional damper mount cannot effectively suppress the vibration from the damper device from being transmitted to the vehicle body depending on the road surface condition or the vehicle speed, and may not improve the riding comfort.

  On the other hand, conventionally, the spring constant of the rubber bush of the damper mount is generally set so as to exhibit optimum vibration isolation characteristics under various stochastic conditions on various road surfaces and environments. . For this reason, the conventional damper mount has not been able to ensure optimum riding comfort on a local road surface or the like.

  The problem to be solved by the present invention is to make it possible to variably set the vibration isolation characteristics of the damper mount and to ensure optimum riding comfort over a wide area.

  A damper mount according to the present invention is a damper mount for connecting a damper device of a vehicle suspension to a vehicle body, the damper mount being disposed between the damper device and the vehicle body, and having one side connected to the damper device, A rubber bushing having a side connected to the vehicle body; and an actuator that elastically deforms the rubber bushing to change an apparent spring constant of the rubber bushing.

  In the damper mount according to the present invention, preferably, the rubber bush has a cylindrical shape, the outer peripheral side is connected to the vehicle body, the rod of the damper device vertically penetrates the center hole, and abuts against the upper end surface in the axial direction. The actuator is connected to the rod in a manner sandwiched in the axial direction by an upper washer and a lower washer in contact with the lower end surface in the axial direction, and the actuator displaces one of the upper washer and the lower washer toward the other. The rubber bush is compressed and elastically deformed by the displacement.

  The damper mount control device according to the present invention is the damper mount control device according to the above-described invention, and includes vehicle running state detecting means for detecting the running state of the vehicle, and vehicle running detected by the vehicle running state detecting means. Actuator control means for controlling the operation of the actuator according to the state.

  In the damper mount control device according to the present invention, preferably, the vehicle running state detection means includes vehicle speed detection means for detecting a vehicle speed, and the actuator control means is high when the vehicle speed detected by the vehicle speed detection means is low. The operation of the actuator is controlled so that the amount of elastic deformation of the rubber bush increases as compared with time.

  In the damper mount control device according to the present invention, preferably, the vehicle travel state detection means includes travel road surface state detection means for detecting a state of a travel road surface of the vehicle, and the actuator control means includes the travel road surface state detection means. When the degree of unevenness of the traveling road surface detected by the above is small, the operation of the actuator is controlled so that the amount of elastic deformation of the rubber bush increases compared to the case where the degree of unevenness is large.

  According to the damper mount of the present invention, the apparent spring constant of the rubber bush can be changed by elastically deforming the rubber bush by the actuator, so that the vibration isolation characteristics of the damper mount can be varied by controlling the operation of the actuator. It can be set, and optimal ride comfort can be ensured over a wide area.

  An embodiment of a damper mount according to the present invention will be described below with reference to FIGS.

  First, an overall configuration example of a vehicle suspension including a damper mount according to the present embodiment will be described with reference to FIG. The illustrated vehicle suspension is a double wishbone type rear suspension. The rear suspension includes a knuckle 21 that rotatably supports the rear wheel 10, an upper arm 22 and a lower arm 23 that connect the knuckle 21 to the vehicle body 1 so as to be movable up and down, a damper device 24, and a suspension coil spring 25.

  The upper arm 22 and the lower arm 23 have base ends connected to the vehicle body (not shown) via rubber bushes 25 and 26, respectively, and tip ends connected to the upper and lower portions of the knuckle 21 via ball joints 27 and 28, respectively. .

  The damper device 24 is of a cylinder-piston type and is a general damper device that exhibits a vibration damping effect by viscous resistance. In the damper device 24, the lower end portion of the cylinder tube 30 is connected (coupled) to the knuckle 21, and the upper end of the piston rod 31 is connected (coupled) to the vehicle body 100 by the damper mount 40. The damper device 24 may be a damping capability variable type damper device.

  The suspension coil spring 25 is engaged with a lower spring retainer 32 attached to the cylinder tube 30 at the lower end, and is engaged with an upper spring retainer 32 connected to the vehicle body 100 at the upper end. It acts as a compression spring.

  Next, details of the damper mount 40 will be described with reference to FIG. The damper mount 40 includes a rubber bush 41 and a piezo actuator 60.

  The rubber bush 41 is made of a rubber-like elastic body made of rubber or a rubber-like product, has a cylindrical shape, and is integrally bonded by vulcanization bonding or the like with the outer cylinder 42 on the outer peripheral side and the inner cylinder 43 on the inner peripheral side. The inside of the inner cylinder 43 is a center hole 44.

  The outer cylinder 42 integrally has a flange portion 45 that forms an outer casing. The flange portion 45 is fixedly connected to the vehicle body 100 by a plurality of bolts 47 and nuts 48 together with the mounting plate 46 of the upper spring retainer 32. The vehicle body 100 has an opening 101 through which the rubber bush 41 is inserted vertically.

  The rubber bush 41 integrally includes an upper end protruding portion 41A that protrudes outward from the upper ends of the outer cylinder 42 and the inner cylinder 43, and a lower end protruding portion 41B that protrudes downward from the lower ends of the outer cylinder 42 and the inner cylinder 43. Have.

  A small diameter portion 31A of the tip of the piston rod 31 of the damper device 24 penetrates the center hole 44 vertically. An intermediate portion of the piston rod 31 has a stepped portion 31C formed by a distal end small diameter portion 31A and a proximal end large diameter portion 31B. The stepped portion 31C is located at the distal end side, that is, at the distal end small diameter portion 31A. A lower washer 48, an inner cylinder 43, and an annular upper washer 49 are passed in order. The upper washer 49 is in contact with the upper surface (the upper end surface in the axial direction) of the upper end protruding portion 41A of the rubber bush 41, and the lower washer 48 is in contact with the lower surface (the lower end surface in the axial direction) of the lower end protruding portion 41B of the rubber bush 41. .

  The upper surface of the upper end protruding portion 41A of the rubber bush 41 and the lower surface of the lower end protruding portion 41B of the rubber bush 41 are each an annular plane (a plane orthogonal to the central axis). The upper washer 49 and the lower washer 48 have an annular plane (a plane orthogonal to the central axis) wider than the upper surface of the upper end protruding portion 41A of the rubber bush 41 and the lower surface of the lower end protruding portion 41B of the rubber bush 41. Are uniformly in contact with the entire upper surface of the upper end protruding portion 41A and the lower surface of the lower end protruding portion 41B of the rubber bush 41.

  The distal end portion of the distal end small diameter portion 31A is a threaded portion 31D, and a fastening nut 50 is threadedly engaged with the threaded portion 31D. Thereby, the rubber bush 41 is connected to the piston rod 31 together with the piezoelectric actuator 60 in a mode sandwiched between the upper washer 49 and the lower washer 48 in the axial direction.

  In this way, the rubber bush 41 is disposed between the damper device 24 and the vehicle body 100, one side is connected to the damper device 24, and the other side is connected to the vehicle body 100.

  The piezo actuator 60 is formed by laminating a plurality of annular piezo elements 63 between an annular upper plate 61 and a lower plate 62, and includes a stepped portion 31 </ b> C between the lower washer 48 and the piston rod 31. It is sandwiched between.

  The piezo actuator 60 is reversibly extended by energization of the piezo element 63 and is displaced in a direction to approach the lower washer 48 and the upper washer 49. Due to the displacement of the upper washer 49, the rubber bush 41 undergoes compression elastic deformation. The compression elastic deformation of the rubber bush 41 can be quantitatively set by increasing or decreasing the current value supplied to the piezo element 63.

  The rubber bush 41 changes its apparent spring constant in a higher direction by this compression elastic deformation. The apparent spring constant of the rubber bush 41 can be quantitatively variably set by increasing / decreasing the current value supplied to the piezo element 63. The current value supplied to the piezo element 63 can be set according to the vehicle speed and the traveling road surface of the vehicle. By controlling according to the vehicle running condition such as the state, the transmission of the running vibration to the vehicle body due to the friction of the damper device over the wide area is effectively suppressed, and the optimal riding comfort is ensured over the wide area. be able to.

  The compression elastic deformation of the rubber bush 41 by the piezo-type actuator 60 is opposite to each other from the lower washer 48 and the upper washer 49 to the upper surface of the upper end protruding portion 41A of the rubber bush 41 and the lower surface of the lower end protruding portion 41B of the rubber bush 41. The upper washer 49 and the lower washer 48 have an annular plane wider than the upper surface of the upper end protruding portion 41A of the rubber bush 41 and the lower surface of the lower end protruding portion 41B of the rubber bush 41, The upper surface of the upper end protruding portion 41A of the rubber bush 41 and the entire lower surface of the lower end protruding portion 41B of the rubber bush 41 are in uniform contact with each other, the upper washer 49, the lower washer 48 and the upper end protruding portion 41A of the rubber bush 41. The upper surface and the lower surface of the lower end protruding portion 41B of the rubber bush 41 are mutually in planes perpendicular to the central axis. By being parallel contact, compressive elastic deformation of the rubber bush 41 by the piezoelectric element 63, as viewed around the circumference of the rubber bushing 41, it will not be performed unevenly.

  As a result, when the rubber bush 41 is compressed and elastically deformed by the piezo actuator 60, there is no biased load on the piston rod 31 and the vehicle body 100 of the damper device 24, causing the piston rod 31 to be twisted and the vehicle body 100 to be deformed. There is no.

  The rubber bush 41 is compressed and elastically deformed in a state of being substantially surrounded and restrained by a highly rigid outer cylinder 42, inner cylinder 43, upper washer 49, and lower washer 48 made of metal. The apparent spring constant of the rubber bush 41 is effectively increased.

  Next, a control device for the damper mount 40 having the above-described configuration will be described with reference to FIG. The control device includes electronically controlled actuator control means 70 such as a microcomputer.

  The actuator control means 70 inputs the vehicle speed detected by the vehicle speed sensor 71 and the vertical acceleration detected by the vertical acceleration sensor 72 as the running state of the vehicle, and the optimum current value (control for the piezoelectric actuator 60) according to these inputs. Target current value) is calculated according to a preset control law, and a signal indicating the calculated control target current value is passed to the current control means 73.

  The vertical acceleration sensor 72 constitutes a traveling road surface state detecting means, and detects the vertical acceleration of the vehicle body, that is, pitching, in other words, the degree of unevenness of the traveling road surface.

  As a result, the current control unit 73 sets the current value to be supplied to the piezo actuator 60 to the control target current value, and allows the current based on the control target current value to flow to the piezo actuator 60.

Below, the example of control by the actuator control means 70 is demonstrated.
(1) The current value supplied to the piezo actuator 60 is controlled so that the elastic deformation amount of the rubber bush 41 is increased when the vehicle speed is low compared to when the vehicle speed is high. More preferably, as the vehicle speed is lower, the value of the current supplied to the piezo actuator 60 is increased continuously or stepwise. Thereby, the compression elastic deformation amount of the rubber bush 41, in other words, the spring constant of the rubber bush 41 increases continuously or stepwise as the vehicle speed decreases.

  The damper friction changes according to the vehicle speed. For example, since it is difficult for a momentary heavy load to be applied at low speed, it is difficult for the damper device 24 to receive a thrust force or a pressing force exceeding static friction (sliding friction between the piston outer peripheral surface of the damper device 24 and the cylinder inner peripheral surface). That is, the damper device 24 is in a state where it is difficult to exhibit the function of attenuating vibration by expanding and contracting. In this state, the input load is not attenuated by the damper device 24, and low frequency vibration is directly transmitted to the vehicle body 110. To prevent this, the damper mount 40 in a high spring constant state is used.

Thus, since the damper device 24 is in a state in which it is difficult to exhibit the damping function at low vehicle speeds, increasing the spring constant of the damper mount 40 increases the low-frequency vibration blocking effect (vibration insulation effect), and the vehicle body 100. It is possible to effectively suppress the transmission of low-frequency vibrations.
(2) When the unevenness of the traveling road surface is small (good road), the piezo-type actuator 60 is arranged so that the amount of compressive elastic deformation of the rubber bush 41 increases as compared with the case where the unevenness is large (bad road). Controls the current value to be energized. More preferably, the smaller the degree of unevenness, the greater the value of the current applied to the piezo actuator 60 continuously or stepwise. Thereby, the amount of elastic deformation of the rubber bush 41, in other words, the spring constant of the rubber bush 41 increases continuously or stepwise as the road is better.

  The usefulness of this will be described.

  During traveling on a good road, it is difficult for the damper device 24 to receive a thrust force or a pressing force exceeding static friction (sliding friction between the piston outer peripheral surface of the damper device 24 and the cylinder inner peripheral surface). Under such an environment, by increasing the spring constant of the damper mount 40, the low frequency vibration blocking effect is enhanced, and the low frequency vibration can be effectively suppressed from being transmitted to the vehicle body 100.

  In the above-described embodiment, the spring constant is increased by compressive elastic deformation of the rubber bush 41. On the contrary, the rubber bush 41 having a relatively high spring constant is used in the initial state, and the elastic elastic deformation of the rubber bush 41 is performed. May reduce the spring constant.

  The actuator for elastically deforming the rubber bush 41 is not limited to the piezoelectric actuator 60, and may be an electromagnetic linear actuator or a combination of a rotary linear actuator and a cam. Note that the piezo actuator 60 can be provided on the upper washer 49 side, and if necessary, may be provided on both the lower washer 48 side and the upper washer 49 side.

1 is a perspective view showing the overall configuration of one embodiment of a vehicle suspension including a damper mount according to the present invention. It is a longitudinal cross-sectional view of the principal part of one Embodiment of the suspension for vehicles containing the damper mount by this invention. It is a block diagram which shows one Embodiment of the control apparatus of the damper mount by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rear wheel 21 Knuckle 22 Upper arm 23 Lower arm 24 Damper device 25 Suspension coil spring 40 Damper mount 41 Rubber bush 60 Piezo-type actuator 70 Actuator control means 71 Vehicle speed sensor 72 Vertical acceleration sensor 100 Vehicle body

Claims (5)

A damper mount for connecting a vehicle suspension damper device to a vehicle body,
A rubber bush disposed between the damper device and the vehicle body, one side connected to the damper device, and the other side connected to the vehicle body;
An actuator that elastically deforms the rubber bush to change the apparent spring constant of the rubber bush;
Damper mount with. The rubber bush has a cylindrical shape, the outer peripheral side is connected to the vehicle body, the rod of the damper device passes vertically through the center hole, and the upper washer that contacts the upper end surface in the axial direction and the lower end surface in the axial direction Connected to the rod in a manner sandwiched in the axial direction by the lower washer,
2. The damper mount according to claim 1, wherein the actuator displaces one of the upper washer and the lower washer toward the other and compresses and elastically deforms the rubber bush by the displacement. 3. The damper mount control device according to claim 1 or 2,
Vehicle running state detecting means for detecting the running state of the vehicle;
Actuator control means for controlling the operation of the actuator according to the running state of the vehicle detected by the vehicle running state detection means;
A damper mount control device. The vehicle running state detection means includes vehicle speed detection means for detecting a vehicle speed,
4. The damper mount according to claim 3, wherein the actuator control means controls the operation of the actuator so that an elastic deformation amount of the rubber bush increases when a vehicle speed detected by the vehicle speed detection means is low as compared to when the vehicle speed is high. Control device. The vehicle traveling state detection means includes traveling road surface state detecting means for detecting the state of the traveling road surface of the vehicle,
The actuator control means is configured to increase the amount of elastic deformation of the rubber bush when the unevenness of the traveling road surface detected by the traveling road surface state detecting means is small compared to when the unevenness is large. The damper mount control apparatus of Claim 3 which controls operation | movement of.

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