JP2801245B2 - Vehicle suspension characteristics measurement method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension characteristic measuring method for measuring the characteristics of a vehicle suspension.

[Conventional technology]

The vehicle wheels and the vehicle body are connected by a suspension, and its characteristics are important factors that greatly affect the vehicle vibration, ride comfort, and maneuverability. Therefore, various measurements are performed using the characteristics of the suspension as basic vehicle characteristics.

When performing this type of measurement, since it is extremely troublesome and practically impossible to perform the measurement while actually running the vehicle, it is necessary to form the same state as the actual running state without actually running the vehicle. Various measurements are taken. As an apparatus for forming a state similar to the actual running state, there is a vehicle basic characteristic measuring apparatus in which wheels of a vehicle are loaded and moved up and down to roll or the like.

When this device is used, as shown in FIG.
In the same state as when the vehicle body B is released and the wheels H are stopped on the ground E, the wheels H of the vehicle S are put on the platform P of the vehicle basic characteristic measuring device as shown in FIG. With the vehicle body B of the vehicle S fixed to the ground E, the left and right wheels H can be formed by applying a standard load Wl, Wr (Wl + Wr = W; constant with the vehicle weight) to each wheel and setting it at a predetermined position. is necessary.

However, when the wheel H is stopped on the ground E, as shown in FIG. 8, it is not clear where the vehicle body B of the vehicle S stops within the range of Δh, and the vehicle B stops at an arbitrary position within the width of Δh. I do. This is because the hysteresis characteristic peculiar to suspension friction due to suspension friction, that is, the characteristic that the relationship between the load and the vertical stroke becomes different when the load increases and when the load decreases. Because it exists. Therefore, the vehicle B of the vehicle S is fixed to the ground E as shown in FIG.
When the vertical load is applied in synchronization with the vertical stroke, the relationship between the vertical stroke and the force on the wheel contact surface is as shown in FIG. 10, and even if the same standard load Wl, Wr is applied to the left and right wheels H. A difference Δh occurs in the stroke. The tenth
In the figure, the solid line shows the characteristics of the left wheel, and the dotted line shows the characteristics of the right wheel.

By the way, in order to measure the various characteristics of the suspension, generality must be measured unless the reference point is the position of h, which is half of Δh, that is, the intermediate position between the load increasing direction and the decreasing direction. Some measurements cannot be taken.

[Problems to be solved by the invention]

However, as described above, the test must be performed with a predetermined reference point as a starting point. However, it is not engineeringly possible to exactly match this point at the start of the test in actual measurement. This is because the hysteresis of the front and rear points is related, and it is difficult to fix both the load and the vertical stroke at a predetermined position. Therefore, there has been a problem that it is difficult to obtain an accurate measurement value in the conventional measurement of suspension characteristics.

Accordingly, an object of the present invention is to provide a vehicle suspension characteristic measuring method that can easily and accurately set a reference point at the start of a test and can easily measure an accurate suspension characteristic.

[Means for solving the problem]

In order to solve the above-mentioned problem, the present invention fixes the vehicle body to the ground as shown in the flowchart of FIG.
1) The left and right wheels of the vehicle on which the vehicle body is fixed are reciprocated up and down one step (step S2a), and data on the vertical displacement position of each wheel and the load at this displacement position at this time are collected (step S2b). ), A displacement position at a standard load at each direction displacement is obtained from the collected data (step S2c),
An intermediate position of the two displacement positions or a load corresponding to the intermediate position is determined from the difference between the two determined displacement positions (step S2d), and after each wheel is moved up and down to the intermediate position or at each wheel, the intermediate position is determined. After applying the load corresponding to the position, the left and right wheels are moved up and down so that the load applied to each left and right wheel becomes the standard load (step S2), and this position is set as the reference point at the start of the test, and the load applied to each left and right wheel The test is performed by moving the left and right wheels up and down while keeping the sum of the constants (step S3), and data indicating the state of each part at this time is collected (step S4)
The suspension characteristics are measured based on the collected data (step S5).

(Operation)

In the above procedure, in step S3, in order to determine a reference point when starting a test for moving the left and right wheels up and down while keeping the sum of the loads applied to the left and right wheels constant, the vehicle of the vehicle body fixed to the ground in step S1 The left and right wheels are moved up and down by one reciprocation in step S2a, and data on the vertical displacement position of each wheel and the load at this displacement position at this time are collected in step S2b, and the collected data is used for each direction displacement. The displacement position under the standard load is determined in step S2c, and the intermediate position of the two displacement positions or the load corresponding to the intermediate position is determined in step S2d based on the difference between the two determined displacement positions.
After moving each wheel up and down to the intermediate position or after applying a load corresponding to the intermediate position to each wheel, the left and right wheels are moved up and down so that the load applied to each left and right wheel becomes a standard load, and the left and right wheels are moved. Bring to the reference point at the start of the test.

As described above, when starting the test, when the left and right wheels are positioned at the reference point, in step S3, the test is performed by moving each left and right wheel up and down while keeping the sum of the loads applied to the left and right wheels constant. Data indicating the state of each part at the time is collected in step S4, and the characteristics of the suspension are measured based on the collected data in step S5.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows an example of a mechanism of a vehicle basic characteristic measuring device used in carrying out the method of the present invention. The measuring device shown is a seesaw having a platform which is flush with the left and right wheels of a vehicle as a test object. It employs a force-applying device. Since the force applying devices on which the front wheels and the 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 having an intermediate portion supported on a bearing frame 12 fixed to the upper end of an elevating shaft 11 guided vertically by a guide (not shown) so as to swing left and right. A vertical displacement detector 12a is provided on the support portion, and a swing (roll) angle detector 12b is provided on the support portion. Below the left and right intermediate portion of the platform 13, upper and lower actuators 15 for driving the platform 13 in the vertical direction are respectively connected. Each actuator 15 is a hydraulic motor 15 servo-controlled by a servo valve.
a, and a pair of screw jacks 15b driven by the hydraulic motor 15a.
Is provided with a vertical displacement detector 15c.

Above the left and right intermediate part of the platform 13, a vertical moving frame 16 is connected via a vertical load detector (not shown).
Is provided on the vertical movement frame 16, and a longitudinal movement frame 18 guided movably in the front-rear direction from the static pressure bearing is provided. A left and right moving frame 19 movably guided is provided. A rotating table (pad) 20 rotatably guided by a static pressure bearing is provided on the left and right moving frame 19, and wheels of a vehicle as a test object are mounted on the rotating table 20.

The rotary table 20 is connected to the front-rear frame 18 and the left-right frame 19 in the front-rear direction and the left-right direction, respectively. It moves right and left together according to.

The platform 13 is also hydraulically controlled by a servo valve (not shown), and is hydraulically controlled by a longitudinal actuator 21 for driving the longitudinal frame 18 in the lateral direction via a longitudinal load detector (not shown), and a servo valve (not shown),
A left / right actuator 22 for driving the left / right moving frame 19 in the left / right direction via a left / right load detector (not shown) and a wheel alignment measuring device 23 are provided. Also,
A rotary actuator 24 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) is connected to the rotary table 20.

Note that reference numeral 21a denotes a longitudinal displacement detector that detects displacement of the longitudinal frame 18, 22a denotes a lateral displacement detector that detects displacement of the lateral frame 19, and the rotation angle of the rotary table 20 is a rotation angle (not shown). It is to be detected by a detector. In addition, the vehicle having the left and right wheels mounted on the rotary table 20 has its body fixed to the ground by a fixing device (not shown).

The wheel alignment measuring device 23 has a sensor for detecting a steer angle, a camber angle, a caster angle, and the like of the tire, and outputs a measurement signal thereof.

FIG. 3 is a block diagram showing the circuit configuration of the basic characteristic measuring device. In FIG. 3, reference numeral 200 denotes a control device including a CPU, and the control device 200 includes a display device 20 such as a CRT.
1, floppy disk 202, printer 203, input circuit 204
And a servo circuit 205 are connected. The input circuit 204 includes an amplifier, an A / D converter, and the like. The analog signal from each detector of the mechanism of the basic characteristic measuring device described above with reference to FIG. Input to the device 200. The servo circuit 205 converts a digital signal from the control device 200 into an analog signal.
A converter, a control signal for inputting an analog signal converted by the D / A converter and an analog signal from each detector, and controlling each servo valve of the mechanism of the basic characteristic measuring device described above with reference to FIG. And controls the operation of the actuator.

Next, an embodiment of a method of measuring suspension characteristics according to the present invention using the above-described basic characteristic measuring device will be described.

First, the vehicle body B is fixed to the ground at a position where each of the four wheels T of the vehicle S rides on the rotary table 20 on the platform 13 of the vehicle basic characteristic measuring apparatus described above with reference to FIG. 2 (FIG. 9). Status). In this state, the left and right vertical actuators 15 are driven by displacement control or load control to move the entire platform 13 upward, and put each wheel on the rotary table 20. Then, the platform 13 is further moved upward, and the data relating to the displacement position Z of the left and right wheels and the load W applied to each rotary motion table 20 at this time are stored in a vertical displacement detector 15c and a vertical load detector (not shown). To collect each. When the platform 13 is moved sufficiently upward and the displacement is increased, the load suddenly increases or the displacement hardly occurs even if the load is increased, and then the entire platform 13 is moved downward, and the left and right wheels are also moved. The data on the displacement position Z and the load W of is collected.

Drawing the relationship between the displacement position and the load W based on the data collected as described above results in a hysteresis curve as shown in FIG. In the figure, a solid line shows a hysteresis curve for the left wheel, and a broken line shows a hysteresis curve for the right wheel. Then, based on the collected data, the points of the two displacement positions on the hysteresis curve with respect to the standard load Wl, Wr (known) of each wheel.
With obtaining the D _1, D _2, the difference between the two displacement positions, as shown in FIG. 5 and (D ₂ -D ₁₎ determined for each of the left and right wheels. Next, determine the upper limit load F ₁ and lower load F ₂ at an intermediate position between the points D ₁ and D _2. Here, the stroke limit load point F ₁ is obtained from D _1, D ₂ that pass through the standard load Wl [(D ₂ -D
₁ ) / 2 + D ₁ ] is one load value when passing through, and the lower limit load point F ₂ is the other load value.

When Motoma' upper limit load point F ₁ and lower load point F ₂ as described above, the load control the upper limit load point F ₁ as shown in FIG. 6 as a target value, or corresponding to the upper limit load point F ₁ Stroke The vertical actuator 15 is operated by displacement control using [(D ₂ −D ₁ ) / 2 + D ₁ ] as a target value, or by load control using the lower limit load point F ₂ as a target value as shown in FIG. the stroke [(D ₂ corresponding to the load point F ₂
−D ₁ ) / 2 + D ₁ ] is used as the target value to operate the vertical actuator 15 by displacement control.

When the target value is reached, the control is switched to load control in any case, and the vertical actuators for the left and right wheels are operated with the standard loads Wl and Wr as the target values. Thus, the left and right wheels of the vehicle S reaches the intermediate position O of the normal load points D ₁ and D _2, wheel by switching the control reaches this position O to the displacement control is held in that position, subsequent suspension Be prepared for the start of various tests.

As a result, the reference point at the start of the test can be accurately and easily set, and accurate measurement of suspension characteristics can be easily performed.

(Effect)

As described above, according to the method of the present invention, the test is performed by moving each left and right wheel up and down while keeping the sum of the loads applied to each left and right wheel constant, collecting data indicating the state of each part at this time, In measuring the characteristics of the suspension based on the collected data, the left and right wheels of the vehicle of the vehicle body fixed to the ground are moved up and down one reciprocation, and the vertical displacement position of each wheel at this time, the load at this displacement position and And the displacement position at the standard load at each direction displacement is obtained from the collected data, and the difference between the two displacement positions thus obtained is the intermediate position of the two displacement positions or the load corresponding to the intermediate position. After moving each wheel up and down to the intermediate position or after applying a load corresponding to the intermediate position to each wheel, the left and right wheels are moved up and down so that the load applied to each left and right wheel becomes a standard load, and left Since as bring the wheel to the reference point of time of start of the test, will be able to accurately and easily establish a reference point at the start of the test, it is possible to easily perform accurate measurement of the suspension characteristic.

[Brief description of the drawings]

FIG. 1 is a view showing a procedure of a vehicle suspension characteristic measuring method according to the present invention, and FIGS. 2 and 3 show a mechanism portion and an electric circuit portion of a vehicle basic characteristic measuring device used for carrying out the method of the present invention. FIG. 4 is a characteristic diagram showing the relationship between the displacement position and the load when a load is applied to the wheels while fixing the vehicle body of the vehicle, and FIG. 5 is a reference for measuring the suspension. FIGS. 6 and 7 are diagrams for explaining a method of setting a test start in one method according to the present invention, and FIG. 8 is a vehicle body position when the vehicle is stationary on the ground. FIG. 9 is a simplified diagram showing a state in which the vehicle is mounted on a platform of a basic characteristic measuring device, and FIG. 10 is a displacement position when a load is applied to wheels with the vehicle body fixed. And load on the left and right wheels Is a characteristic view showing had. S ...... vehicle, H ...... wheels, B ...... vehicle, D _1, D ₂ ...... displacement position, F _1, F ₂ ...... load, the difference Δh ...... displacement position.

Claims (1)

(57) [Claims] 1. A vehicle body is fixed to the ground, and the left and right wheels of the vehicle to which the vehicle body is fixed are reciprocated up and down by one reciprocation. At this time, data relating to the vertical displacement position of each wheel and the load at this displacement position are obtained. Collecting, obtaining a displacement position at a standard load at each direction displacement from the collected data, obtaining an intermediate position between the two displacement positions or a load corresponding to the intermediate position based on a difference between the obtained two displacement positions, After moving each wheel up and down to the intermediate position or after applying a load corresponding to the intermediate position to each wheel, the left and right wheels are moved up and down so that the load applied to each left and right wheel becomes a standard load, and this position is tested. As a reference point at the start, the test is performed by moving each left and right wheel up and down while keeping the sum of the loads applied to each left and right wheel constant, collecting data indicating the state of each part at this time, and based on the collected data Suspension characteristics Vehicle suspension characteristic measuring method for measuring.