JPH02221840A - Measurement of vehicle suspension characteristic - Google Patents

Abstract

PURPOSE:To easily perform an accurate measurement of characteristics for a vehicle suspension by utilizing one of displacing positions in the vertical direction and two displacing positions with a standard load as a reference point at the starting time for test for convenience sake. CONSTITUTION:Before wheels of the vehicle to be tested are placed on a platform 13 to set them on a specified position put with the standard load at the starting time for test, the left/right wheels are moved up and down one time using a vertically movable frame 16 by means of moving the platform 13. Then, each displaced position with the standard load at the time displacing in the vertical direction are obtained based on collected data regarding the displaced positions of each wheel in the vertical direction and load at these displaced positions. Next, the positions of the left/right wheels are set on one side of the displaced positions obtained to test with the standard load and the test result is corrected by the difference between two displaced positions thereafter. Consequently, the measurement for the characteristics for the vehicle suspension can be performed by accurate and easy operations since the reference point settled for convenience sake is corrected later on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle suspension characteristic measuring method suitable for measuring vehicle suspension characteristics, particularly roll center height.

[Conventional technology]

The wheels of a vehicle and the vehicle body are connected by a suspension, and the characteristics of the suspension are important because they have a large effect on the vibration, ride comfort, and maneuverability of the vehicle. Therefore, various measurements are performed using the characteristics of this vehicle suspension as basic vehicle characteristics.

When performing this type of measurement, it is extremely troublesome and virtually impossible to actually drive the vehicle and perform the measurement.
Various measurements are performed by creating conditions similar to actual driving conditions without actually driving the vehicle. As a device for forming a state similar to the actual driving state, there is a basic vehicle characteristic measuring device that moves the wheels of a vehicle up and down to perform rolls and the like.

When this device is used, the same state as when the vehicle body B of the vehicle S is freed and each wheel H is stationary on the ground E as shown in FIG. Place the wheels H of the vehicle S on the platform E of the characteristic measuring device,
And with the body B of the vehicle S fixed on the ground E, standard loads Wl and Wr are applied to the left and right wheels H (Wj!+Wr=
It is necessary to form it by multiplying by W (constant depending on the weight of the vehicle) and setting it at a predetermined position.

However, when the wheels H are brought to rest on the ground E, as shown in Fig. 8, it is not certain where within the range of Δh the body B of the vehicle S will come to rest; do.

This is due to the hysteresis characteristic peculiar to vehicle suspension characteristics such as the suspension's flexibbon, in which the relationship between load and vertical stroke becomes different when the load is increased and when it is decreased. This is because there exists. Therefore, as shown in Fig. 9, the body B of the vehicle S is fixed to the ground E, and both axles H
When a force is applied in the vertical direction synchronously, the relationship between the vertical stroke and the force on the wheel contact surface becomes as shown in Figure 1O, and the same standard loads W l and W r are applied to the left and right wheels H. However, there will be a difference in stroke of Δh. Note that the solid line in FIG. 10 indicates the characteristics of the left wheel, and the dotted line indicates the characteristics of the right wheel.

By the way, in order to measure various characteristics of the suspension, it is generally necessary to measure with the position h, which is 1/2 of Δh, that is, the intermediate position between the direction of increase in load and the direction of decrease in load, as a reference point. Unable to perform certain measurements.

For example, the roll center height of a vehicle suspension may be measured as one of the vehicle suspension characteristics.

In such a case, as shown in Fig. 11, with the wheels H of the vehicle S placed on the platform of the vehicle basic characteristics measuring device and the body B of the vehicle S fixed to the ground, the left and right wheels are The wheels are set at a predetermined position with a standard load applied, and then the platform is rolled so that the sum W (vehicle weight) of the loads W l and W r applied to each wheel is always constant, and the tread length at that time is determined. The locus R of the grounding points of the left and right wheels H is determined from the relationship between the change in T and the change in the vertical displacement position of each wheel. Then, the angle θ formed by the normal line perpendicular to the tangent line 2 at the predetermined position point (reference point) with respect to this trajectory and the ground plane.

θ7 is calculated, and the calculated angle θ3. θ, and the tread length T, the suspension roll center height hrt and h7.corresponding to the left and right wheels are determined by the following formula. .

I'm looking for.

h,,=T 1-tan θ.

h,,=Tr-tan θ.

Note that Tl and Tr are the tread lengths proportionally divided according to the position of the center of gravity WC, and this is the load W/! that is applied to each wheel when the vehicle body B is not fixed. , Wr and the tread length T by the following formula.

Figure 12 depicts the trajectory R of the grounding point of the wheel H, with the horizontal axis representing the vertical displacement position Z of the wheel and the vertical axis representing the tread length T, based on the standard load position. By determining the angle θ between the tangent at the reference point to the curve and the horizontal axis for each wheel, 11rL is obtained using the above formula.
and can be determined by calculation.

[Problem to be Solved by the Invention] However, as mentioned above, when measuring vehicle suspension characteristics, it is necessary to conduct the test using a predetermined reference point as the starting point. It is engineering impossible to match accurately. This is because hysteresis between the front and rear points is involved, and it is difficult to fix both the load and the vertical stroke at predetermined positions. For this reason, in the conventional measurement of vehicle suspension characteristics, particularly the roll center height of a vehicle suspension, there has been a problem in that it is difficult to obtain accurate measured values.

Therefore, the first object of the present invention is to provide a method for measuring vehicle suspension characteristics that can easily and accurately set a reference point at the start of a test and that can easily and accurately measure vehicle suspension characteristics. .

A second object of the present invention is to provide a method for measuring vehicle suspension characteristics that can easily and accurately set a reference point for starting a test, and can easily and accurately measure the roll center height of a vehicle suspension. This is an issue.

[Means to solve the problem]

In order to solve the first problem mentioned above, the method for measuring vehicle suspension characteristics according to the present invention fixes the vehicle body to the ground and measures the basic vehicle characteristics of the left and right wheels, as shown in the procedure diagram of FIG. 1(a). Place it on the platform of the measuring device (step S1), then move the platform to apply a standard load to the left and right wheels (step S2), and in this state, move the left and right wheels up and down while keeping the sum of the loads applied to each constant. In the test step S3), data indicating the state of each part at this time is collected.Step S4), and the characteristics of the vehicle suspension are measured based on the collected data (step S5). Before applying the load, the platform is moved to move the left and right wheels up and down once in a round trip (step 52a), and data regarding the vertical displacement position of each wheel at this time and the load at this displacement position is collected (step 52b). From the collected data, the displacement position under standard load during upward and downward displacement is determined (step 52c), and then the platform is moved to set the position of the left and right wheels at a predetermined position of one of the two displacement positions determined above. The standard load is applied to the left and right wheels (step S2), and after setting the position, the test result obtained by performing the test is corrected based on the difference between the two displacement positions (step S6).

In order to solve the second problem mentioned above, the method for measuring vehicle suspension characteristics according to the present invention, as shown in the procedure diagram of FIG. is placed on the platform of the vehicle basic characteristics measuring device and a standard load is applied (step S2).
In this state, the left and right wheels are rolled while keeping the sum of the loads applied to each constant (step S3). The inclination angle of the tangent line at the position where the standard load is applied is determined (step S4), and the roll center height of the vehicle suspension relative to each wheel is measured based on the inclination angle and the tread length (step S5).
In the method, before applying a standard load to the left and right wheels placed on the platform, move the platform to move the left and right wheels up and down in a reciprocating manner (Step 52a), and at this time, the vertical displacement position of each wheel and this displacement position are determined. (step S2b), and from the collected data, determine the displacement position under the standard load at the time of upward and downward displacement (step 520), and then move the platform to calculate the two determined values. The positions of the left and right wheels are set at one of the displacement positions, a standard load is applied to the left and right wheels (step S2), and the roll center height obtained by performing the roll test after setting the position is determined as described above. It is characterized in that correction is performed based on the difference between the two displacement positions (step S6).

[Operation] In the method of the present invention, which was made to solve the first problem mentioned above, at the start of the test, the wheels of the vehicle under test are placed on the platform of the vehicle basic characteristics measuring device, and the wheels are placed at a predetermined position with a standard load applied. Before setting, in step S2a, the platform is moved and the left and right wheels are moved up and down once, and based on the data regarding the vertical displacement position of each wheel and the load at this displacement position collected in step S2b, step In S2c, each displacement position under the standard load at the time of upward and downward displacement is determined, and in Step S2, the position of the left and right wheels is set to one of the determined displacement positions and a standard load is applied, and in Steps S3 to S5. After the test, the test result is corrected based on the difference between the two displacement positions in step S6.

Therefore, a convenient position that can be set relatively accurately and easily is used as the reference point at the start of the test for the left and right wheels, and since the conveniently set reference point is later corrected, it is more accurate than before. Furthermore, vehicle suspension characteristics can be measured with simple operations.

In addition, in the method achieved by the present invention to solve the second problem described above, before applying a standard load to the left and right wheels placed on the platform of the vehicle basic characteristics measuring device, the platform is moved in step S2a to align the left and right wheels. Two displacement positions (point a in Fig. 4) under the standard load determined in step S2c based on the data regarding the vertical displacement position and the load at this displacement position collected in step S2b during reciprocating vertical movement and a/)
In step S2, the platform is moved to set the left and right wheels to the above-mentioned one position, and a standard load is applied to the left and right wheels.
The roll center height measured in step S6 is
In this case, correction is made based on the difference between the two displacement positions (DZ in FIG. 5) under the standard load determined based on the collected data.

Therefore, a convenient position that can be set relatively accurately and easily is used as the reference point when the left and right wheels start rolling, and the conveniently set reference point is later corrected.
The roll center height can be measured more accurately and with simpler work than in the past.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an example of the mechanism of a vehicle basic characteristic measuring device used in carrying out the method of the present invention. A type applying device is adopted. Since the force applying devices on which the front wheels and rear wheels are respectively mounted have the same configuration, only one of them is shown in the figure.

The force applying device has a platform 13 whose middle part is supported so as to be able to swing from side to side on a bearing frame 12 which is fixed to the upper end of a lifting shaft 11 that is guided to be able to move up and down by a guide (not shown). Vertical displacement detector 12a
However, each supporting portion is provided with a swing (roll) angle detector 12b. Vertical actuators 15 that drive the platform 13 in the vertical direction are connected below the left and right intermediate portions of the platform 13, respectively. Each actuator 15 includes a hydraulic motor 15a that is servo-controlled by a servo valve, and a pair of screw jacks 15b that are driven by the hydraulic motor 15a.
Each screw jack 15b has a vertical displacement detector 1.
5c is provided.

Further, a vertically movable frame 1 is provided above the left and right intermediate portions of the platform 13 via a vertical load detector (not shown).
6 is provided, and on the vertically moving frame 16, there is provided a longitudinally moving frame 18 which is guided so as to be movable in the front and rear directions by hydrostatic pressure bearings. A lateral movement frame 19 is provided which is movably guided. And left and right frame 1
A rotary table (pad) 20 rotatably guided by a hydrostatic bearing is provided on the rotary table 9, and the wheels of a vehicle as a specimen are mounted on the rotary table 20.

The rotary table 20 is connected to the longitudinal movement frame 18 and the lateral movement frame 19 in the longitudinal direction and the lateral direction, and moves back and forth together with the longitudinal movement of the longitudinal movement frame 18, and the lateral movement of the lateral movement frame 19. It is designed to move left and right together depending on the situation.

The platform 13 also includes a longitudinal actuator 21 which is hydraulically controlled by a servo valve (not shown) and drives the longitudinal movement frame 18 in the left and right direction via a longitudinal load detector (not shown), and a longitudinal actuator 21 which is hydraulically controlled by a servo valve (not shown) and drives the longitudinal movement frame 18 in the left and right directions via a longitudinal load detector (not shown). A left and right actuator 22 drives the moving frame 19 in the left and right direction via a left and right load detector (not shown).
and a foil alignment measuring device 23 are provided. Further, a rotary actuator 24 is connected to the rotary table 20, which is hydraulically controlled by a servo valve (not shown) and drives the rotary table 20 in a rotational direction via a torque detector (not shown).

Note that 21a is a longitudinal displacement detector that detects the displacement of the longitudinally moving frame 18, 22a is a lateral displacement detector that detects the displacement of the laterally moving frame 19, and the rotation angle of the rotary table 20 is determined by the rotation (not shown). It is designed to be detected by an angle detector. Further, the vehicle body with left and right wheels placed on the rotary table 20 is fixed to the ground by a fixing device (not shown).

The wheel alignment measuring device 23 has a sensor for detecting the steer angle, camber angle, caster angle, etc. of the tire, and outputs these measurement signals.

FIG. 3 is a block diagram showing the circuit configuration of the basic characteristic measuring device. In the same figure, 200 is a device consisting of a CPU, a display device 201 such as a CRT, a floppy disk 202, a printer 203, an input circuit 204, and a servo circuit 205. is connected. The input circuit 204 is composed of an amplifier, an A/D converter, etc., and converts analog signals from each detector of the mechanism section of the basic characteristic measuring device described above with reference to FIG. 2, the foil alignment measuring device, etc. into digital signals for control. input into the device 200. The servo circuit 205 includes a D/A converter that converts the digital signal from the control device 200 into an analog signal, and manually converts the analog signal converted by the D/A converter and the analog signal from each detector.
It is composed of a servo amplifier and the like that outputs control signals for controlling each servo valve in the mechanism section of the basic characteristic measuring device described above with reference to FIG. 2, and controls the operation of the actuator.

Next, an embodiment of a method for measuring the roll center height of a suspension by carrying out the vehicle suspension characteristic measuring method according to the present invention using the above-mentioned basic characteristic measuring device will be described below.

First, the vehicle body B is fixed to the ground at a position such that each of the four wheels T of the vehicle S rests on the rotary table 20 on the platform 13 of the vehicle basic characteristic measuring device described above with reference to FIG. In this state, the left and right vertical actuators 15 are driven to move the entire platform 13 upward so that each wheel rides on the rotary table 20. Then, the platform 13 is further moved upward, and data regarding the displacement position Z of the left and right wheels at this time and the load W applied to each rotary table 20 is transmitted to the vertical displacement detector 15.
c and a vertical load detector (not shown). When the platform 13 is moved sufficiently upwards so that almost no displacement occurs even if the load is increased, the entire platform 13 is then moved downwards, and data regarding the displacement position Z and the load W of the left and right wheels is also collected at this time. .

If the relationship between the displacement position Z and the load W is drawn based on the data collected as described above, a hysteresis curve as shown in FIG. 4 will be obtained. In the figure, the solid line shows the hysteresis curve for the left wheel, and the broken line shows the hysteresis curve for the right wheel. Then, based on the data collected above, the standard load Wj2 of each wheel is determined. Wr.
Point a of two displacement positions on the hysteresis curve for (known).

In addition to determining a', the difference DZ between the two displacement positions as shown in FIG. 5 is determined for each of the left and right wheels.

Thereafter, with each wheel T riding on the platform 13, the load detected by the vertical load detector corresponding to each wheel is the standard load Wj2. The platform 13 is moved from bottom to top or from top to bottom by load control so that Wr. As a result, as shown in Fig. 6, which shows the case of one wheel moving from the bottom to the top, the vertical movement of the platform 13 is automatically performed when the load detected by the vertical load detector becomes the standard load. Stop at. This stopping point is the intersection a of the hysteresis curve and the standard load line. The vertical displacement position Z0 and tread length To of the left and right wheels at this time are used as reference points in the subsequent roll test.

Next, the standard load for the left and right wheels W/! , Wr is kept constant and the platform 13 is rolled at an appropriate angle in one direction, for example, with the left wheel facing down. From this state, the platform 13 is rolled to the opposite side, and in the process of this roll, the left and right wheels are rolled. Vertical displacement position Z for each wheel
and tread length T are detected by the vertical displacement detector 15c and the lateral displacement detector 22a, and the detected data are collected. This collected data shows the locus of the grounding point of each wheel, and the relationship between displacement position Z and tread length T is illustrated using this collected data.
The result is as shown in FIG. Next, the inclination angle θ of the tangent to this locus R at the reference point is determined. The inclination angle θ of this tangent is determined by calculating the ratio of the amount of change ΔT in the tread length to the change in the predetermined amount ΔZ in the vertical displacement position from the reference point (Z,,T,). −'
It can be determined from the equation ΔT/ΔZ=θ.

Once the inclination angle θ of the tangent line 2 at the reference point is determined as described above, next the roll center height h for the left and right wheels is determined.
rt+hrr is calculated by the following formula.

If the reference point is a, h rL = T 1-tan θ-D Z/2 If the reference point is a', h,, = TIl-tan θ+D Z/2 Note that DZ is the above-mentioned points a and a' is the difference in displacement position.

〔effect〕

As explained above, according to the present invention, before applying a standard load to the left and right wheels, a load is applied to the left and right wheels and the left and right wheels are moved up and down in one reciprocation, and the displacement position in the vertical direction and the position at this displacement position are collected. One of the two displacement positions at the standard load obtained based on the data regarding the load is conveniently used as a reference point at the start of the test, and the suspension characteristics measured at the predetermined position, especially the roll center height, are 2 at the standard load determined based on the data collected above.
Since the correction is made based on the difference between the two displacement positions,
The position of the reference point at the start of roll for the left and right wheels can now be set more accurately and easily compared to the conventional method of setting the position based only on the standard load, and the suspension characteristics, especially the roll center height The effect is that the measurement can be carried out relatively accurately and easily.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are diagrams showing the steps of the method for measuring vehicle suspension characteristics according to the present invention, respectively. FIGS. 2 and 3 are diagrams showing a vehicle basic characteristic measuring device used to carry out the method according to the present invention. Figure 4 is a characteristic diagram showing the relationship between the displacement position and load for the left and right wheels when the vehicle body is fixed and a load is applied to the wheels. is a diagram for explaining reference points when measuring vehicle suspension characteristics, Figure 6 is a diagram for explaining how to set the test start in the method of the present invention, and Figure 7 is a diagram for explaining the method of setting the test start in the method of the present invention. Figures 8 to 1θ are explanatory diagrams for explaining conventional problems; Figures 11 and 12 are vehicle suspension diagrams. FIG. 2 is an explanatory diagram showing a general method of determining the roll center height of the vehicle. S... Vehicle, H... Wheel, B... Vehicle body, a, a
...Displacement position (predetermined position), DZ...Difference between displacement positions. (○) Figure 1 (b) Figure 4 Figure 6 Figure 7 Figure 7 W! Wr Figure 4h/2 Figure 10

Claims (2)

[Claims] (1) Fix the vehicle body to the ground and place the left and right wheels on the platform of the basic vehicle characteristics measuring device.Then move the platform to apply a standard load to the left and right wheels.In this state, measure the load applied to each of the left and right wheels. In this method, the vehicle suspension is tested by moving it up and down while keeping the sum constant, collecting data indicating the condition of each part at this time, and measuring the characteristics of the vehicle suspension based on the collected data. Before applying a load, move the platform to move the left and right wheels up and down once, collect data regarding the vertical displacement position of each wheel at this time and the load at this displacement position, and use the collected data to determine the upward direction. Then, move the platform to set the left and right wheels at one of the two displacement positions determined above, and apply the standard load to the left and right wheels. . A method for measuring vehicle suspension characteristics, characterized in that the test result obtained by performing the test after setting the position is corrected based on the difference between the two displacement positions. (2) Fix the body of the vehicle to the ground and place the left and right wheels on the platform of the basic vehicle characteristics measuring device.Then move the platform to apply a standard load to the left and right wheels, and in this state, measure the load on each of the left and right wheels. Roll the wheel while keeping the sum constant, and determine the inclination angle of the tangent at the position where the standard load is applied to the trajectory of the wheel grounding point, which is determined from the tread length and the change in the vertical displacement position of the wheel. In the method of measuring the roll center height of the vehicle suspension for each wheel based on the inclination angle and tread length, before applying a standard load to the left and right wheels placed on the platform, the platform is moved and the left and right wheels are moved up and down once in a round trip. At this time, data regarding the vertical displacement position of each wheel and the load at this displacement position is collected, and from the collected data, each displacement position under the standard load at the time of upward and downward displacement is determined, Thereafter, move the platform to set the left and right wheels at one of the two displacement positions obtained, apply a standard load to the left and right wheels, set the position, and then perform the roll test to determine the roll center. A method for measuring vehicle suspension characteristics, characterized in that the height is corrected based on the difference between the two displacement positions.