JPH02234822A - Suspension device - Google Patents

Abstract

PURPOSE:To detect deterioration of a common elastic member, which forms part of a suspension device for the left and right wheels, on the basis of results from sensing by supporting the middle part of elastic member at its two points on the car body, and installing strain sensing means at least at three points. CONSTITUTION:The axle 2 for a wheel 1 is supported by an upper arm 4 and a lower arm 5 through a knuckle 3. Two points, left and right, in the middle of an elastic member 7 stretching long in the direction across the car width and having resilience in the vertical direction are supported on the car body 6 with the aid of supports 8 rotatably and slidably. The two ends of this elastic member 7 are coupled with the middle of the lower arm 5 rotatably. Strain sensing means 9L, 9M, 9R are mounted at three points on the elastic member 7. Deterioration of the elastic member 7 is sensed through comparison of the actual strain measurement with the corresponding theoretical strain value at any point, which is obtained presumatively from the actual strain measurement at a certain point as reference.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a suspension in which the suspension components for the left and right wheels are composed of a common elastic member that is supported by the vehicle body at two points on the left and right in the middle. This is designed to detect deterioration or damage of the elastic member based on the strain at the location. [Prior Art] The present applicant has disclosed in Japanese Patent Application No. 6:1-94074 that a strain detecting means is provided in an elastic member supported by the vehicle body at two points on the left and right in the middle part, which constitutes a common part of the left and right suspensions. proposed to detect the load applied to the suspension or the height of the vehicle by determining the change in stress based on the strain of the elastic member.

[Problems to be Solved by the Invention] Incidentally, from the viewpoint of controlling the motion state of the vehicle and the suspension, it would be useful to detect deterioration of the elastic member over time, damage caused by some external force, etc. in terms of countermeasures. becomes. SUMMARY OF THE INVENTION It is therefore an object of the present invention to prevent deterioration or damage of an elastic member, which is a common component of suspension components for left and right wheels and is supported by the vehicle body at two points on the left and right in the middle, based on strain at at least three points. The purpose of the present invention is to provide a suspension device that can detect [Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention configures the suspension components of the left and right wheels with a common elastic member, and supports the elastic members on the vehicle body at two points on the left and right in the middle. The present invention is characterized in that at least three travel detection means are provided for detecting strain in the elastic member, and deterioration or damage of the elastic member is detected based on the strain. Specifically, one strain detecting means is provided on each of the outer regions of the left and right vehicle body support points of the elastic member, and one strain detection means is provided on the inner region between the vehicle body support points. More specifically, at least one of the strain detection means is provided at a portion of the elastic member where the deterioration rate is different from that of the other strain detection means or at a portion where damage is considered to be possible.

Then, a theoretical value of distortion at another point estimated from the actual measurement value of distortion at a certain point is compared with the actual measurement value of distortion at that other point.

Note that the theoretical value of the distortion is obtained by either data map processing or arithmetic processing.

[Operation] Based on the strains at three or more points on the elastic member obtained from at least three strain detection means, that is, the theoretical value of the strain at another point estimated from the measured value of strain at a certain point and the other point. Deterioration or breakage of the elastic member is detected by comparing the measured value of strain at the point.

If one strain detection means is provided in each of the left and right outer and inner regions of the vehicle body support point of the elastic member, areas of deterioration or damage can be detected. In this case, if at least one strain detection means is provided in a part of the elastic member where the rate of deterioration is different from that of the other strain detection means, or in a part where there is a possibility of damage, deterioration or damage can be detected more effectively. It can be done. In addition, the theoretical value of distortion can be obtained through data map processing and arithmetic processing.

[Example] An example will be explained below based on the attached drawings. 8 in FIGS. 1 and 2, for each member shown on the left and right, l is a wheel, 2 is an axle, 3 is a knuckle, 4 is an upper arm,
5 is a lower arm, 6 is a vehicle body, and 7 is an elastic member to which the present invention is applied.

In other words, the elastic member 7 is a transverse leaf spring that is elongated in the vehicle width direction and has an elastic force in the vertical direction. It is rotatably and slidably supported via support members 8, 8. In the example shown in FIG. 1, the ends of the leaf springs 7 are rotatably connected to the intermediate portions of the left and right lower arms 55, and in the example shown in FIG. Leaf spring 7 at the bottom of .3
The ends of each are rotatably connected. According to the suspension in which the left and right wheels are connected by the elongated horizontal leaf spring 7 supported at two points in the middle of the vehicle body 6 in this way, both the left and right wheels 1.1 side are always held downward by the common leaf spring 7. Because it is energized, it is possible to use a single shock absorber that eliminates the need for a coil spring, and the combination of the vehicle body 6 and leaf spring 7? By providing an arbitrary actuator in between, it is possible to easily add a vehicle height adjustment function, and furthermore, a stabilizer function can be obtained by the leaf spring 7 itself. It is also possible to provide an actuator in the inner viewing area between the vehicle body support points of the leaf spring 7 so that the left and right vehicle height adjusting actuators can be used in common.

In the above suspension, as shown in the figure, for example, the horizontal leaf spring 7 is placed in three different positions, that is, on each of the left and right sides (each outer area of the support member 8) and in the middle area (the inner area between both support members 8.8). distortion detection means 9L, 9w, 9
! Provide l. In particular, a set of 1,000 distortion detection stages 9t. ,9M
(or 9■.9M) are provided at locations with different deterioration rates. Note that at least one part is likely to be damaged by external disturbances (for example, the outer area of the support member 8).
Set it in Areas that are likely to be damaged are likely to be near the wheels due to flying stones, etc., and areas that are likely to deteriorate are near the fulcrum.

Here, the strain detection means 9 detects the strain of the leaf spring 7. A simple structure such as a strain gauge that can detect changes in the amount of strain due to strain may also be used. Next, the detection of deterioration or damage of the above-mentioned horizontal leaf spring 7 will be explained. Since aging deterioration can also be detected in the same way as damage, damage detection will be described here.

First, as shown by the broken line in FIG. 3, when the horizontal leaf spring 7 is not damaged, each strain detection means 9L, 9M. The following relationship holds true for the respective strain values εLI+ε■, ε■ detected by 911.

tM,=k. εL1+k2εR1+k3 ・
-(1) However, kr and kz are coefficients determined by the strain detection position,
k is a correction term (because there are parts of an actual leaf spring that do not conform to the beam theory). Now, if the damage occurs at point ■ in Figure 3, the strain value near the damage point shown by the solid line will be large. changes (εLl→εL2). This is due to a decrease in Young's modulus (in some cases, a decrease in section modulus), and the vehicle body leans to the left (point ■ is on the left side of the vehicle body).
yes? Then, the right wheel receives a load and changes somewhat from ε1 to ε3■. However, in the inner region between the left and right fulcrums,
Although the shape of the leaf spring 7 is deformed, there is no stress concentration at any one point, and the strain value near the center hardly changes (eMl→ε.2, see also Figure 4). Here, the measured value of strain at two locations outside the fulcrum εL2ε2■
If we estimate the theoretical value ε゛1 of the strain in the inner region between the supports based on equation (1) above, ε'wx= k IeL1+ kg @*2+ kz
・=(2), and let E be the difference from the actual measured value ε1, then EM■=1(゛U2−6m21
・It can be expressed as -(3). If this EM2 exceeds a certain value, it is determined that the leaf spring 7 is damaged, and damage can be detected. Figure 5 shows the case where point ■ in the inner vehicle area between the fulcrums is damaged.
Contrary to when the outer region is damaged, the strain value in the inner region changes greatly (QMI→ε1), while the outer region hardly changes (
et. +→6. ．． ff+ell→(3,).

? Similarly, if we estimate the theoretical value ε゜0 of the strain in the inner region, then ε'yy=k r @L. + k 2 ε,. +
k, ... (4), and if the difference from the actual measurement value eMff is set as EM3, then EM:I=l ε゛0− ε
M31...
(5), and as in the case of damage to the outer area, E■
becomes larger.

As described above, the strain at one center (nearby) point on the inside is estimated from the strain at the two outside points according to equation (1) above, and compared with the actual measured value.If the difference is greater than a certain value, the leaf spring 7 It can be determined that some bond area (other than points ■ and ■ above) has been damaged. In addition, the theoretical strain values of other parts (゛,,ε゛8
. . are also estimated one by one, and the differences EL, E8, . . . with each actual measurement value are of course compared.

Deterioration (fatigue) can also be detected in the same way. Furthermore, by further increasing the number of strain detection means and appropriately selecting their positions (parts with different deterioration rates or parts where damage is likely), it is possible to increase the accuracy level of damage/deterioration detection. Recognize.

In the above, a computer is used in the actual vehicle to calculate the theoretical value of distortion at each location through memorized data map processing and arithmetic processing, and calculate the size of the difference itself between the theoretical value of distortion and the actual measured value, as well as a predetermined value. As the number of times or time at which the exceeded difference appears is determined to be deterioration or damage, a warning etc. will be issued as deterioration or damage. FIG. 6 shows an example of the determination, and shows the case of formula (3) above, where the predetermined value α is exceeded continuously for a predetermined period of time or a predetermined number of times per unit time (in the figure, 4
It is determined that the leaf spring 7 has deteriorated or has been damaged. This type of judgment makes it possible to take appropriate measures against suspension deterioration or damage, thereby maintaining vehicle safety.

Here, the predetermined values, time, and number of times are set to the most appropriate values according to test results and the like.

As described above, the distortion of the leaf spring 7 in particular is constantly monitored, and by detecting its deterioration or damage, a warning is issued, driving and vehicle speed are regulated, and braking is performed.
Furthermore, it will be effectively used to control the vehicle's motion status and suspension, including controlling vehicle height and attitude, shock absorber control, and steering control. Note that the suspension type is not limited to the double wishbone type of the embodiment, but may be a strout type or the like.

[Effects of the Invention] As described above, according to the present invention, in a suspension in which the suspension components of the left and right wheels are made of a common elastic member supported by the vehicle body at two points on the left and right in the middle part, at least three strains can be avoided. Based on the strains at three or more points on the elastic member obtained from the detection means, that is, comparing the theoretical value of strain at another point estimated from the actual measured value of strain at a certain point with the actual measured value at the other point. Accordingly, deterioration or damage of the elastic member can be detected.

Therefore, it can be effectively used to control the vehicle's motion state and suspension. Then, by providing one strain detecting means in each of the left and right outer regions and the inner region of the vehicle body support point of the elastic member, it is possible to detect areas of deterioration or damage. In addition, by providing at least one strain detection means at a portion of the elastic member where the rate of deterioration is different from that of other strain detection means or at a portion where there is a possibility of damage, deterioration and damage can be detected effectively. Can be done.

[Brief explanation of the drawing]

Figures 1 and 2 are simplified front views of each suspension structure showing an example of application of the present invention, Figure 3 is a simplified front view based on Figure 2 showing an example of damage, and Figure 4 is an outer area Figure 5 is a diagram of the strain state in the case of damage. Figure 6 is a diagram of the strain state in the case of damage to the inner area. Figure 6 shows the relationship between time and the comparative difference between the theoretical value and the measured value of strain, which represents an example of determining deterioration or damage. This is a diagram. In the drawings, 1 is a wheel, 7 is an elastic member, and 9 is a strain detection means. Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. The left and right wheel suspension components are made of a common elastic member, the elastic member is supported on the vehicle body at two points on the left and right in the middle, and at least three suspension members are provided to detect the strain of the elastic member. What is claimed is: 1. A suspension device comprising: a strain detecting means, and detecting deterioration or damage of the elastic member based on the strain. 2. Claim 1, wherein the strain detection means is provided in each of the outer regions of the left and right vehicle body support points of the elastic member, and one strain detection means is provided in the inner region between the vehicle body support points. Suspension device as described. 3. The suspension according to claim 1, wherein at least one of the strain detection means is provided at a portion of the elastic member where the rate of deterioration is different from that of the other strain detection means or at a portion where the possibility of damage is considered. Device. 4. Claims 1 and 2, characterized in that a theoretical value of distortion at another point estimated from the actual measurement value of the distortion at a certain point is compared with the actual measurement value of the distortion at the other point. Or the suspension device according to claim 3. 5. Claim 4, wherein the theoretical value of the distortion is obtained by either data map processing or arithmetic processing.
Suspension device as described.