JPH0735646A - Apparatus for measuring characteristic of leaf spring - Google Patents

Abstract

PURPOSE:To measure a dynamic spring characteristics in a wide range of vibrating frequencies and vibrating amplitudes by one measuring apparatus, by setting a displacement sensor for large amplitude and a displacement sensor for small amplitude to the same leaf spring, and utilizing as an effective one what agrees in phase with a vibrator. CONSTITUTION:Both ends of a leaf spring 2 to be measured are fixed by a jig 3. The central part of the leaf spring 2 is vibrated by 4 and an average of vibration signals is calculated by a measuring means 10. The measuring means 10 first takes signals detected by a displacement sensor 6a for large amplitude, calculates the average, and triggers where the vibration signal is at 0 level thereby to obtain a phase difference A from signals detected by tone displacement. sensor 6a. If the phase difference A is within 5, it is so regarded that the phases agree. Detecting signals of a load sensor 5 are taken, and a characteristic diagram of frequencies of the dynamic spring (displacement- load) is formed. When the phase difference A exceeds 5 deg., signals detected by a displacement sensor 6b for small amplitude are taken to form a characteristic diagram for the dynamic spring in the same procedure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring the characteristics of leaf springs used between a vehicle body and an axle, and the like. The present invention is used to measure the displacement load characteristics of leaf springs. The present invention relates to a device for measuring the characteristics of a leaf spring over a wide range of amplitude and a wide range of vibration frequencies.

[0002]

2. Description of the Related Art A leaf spring to be measured is fixed to one stand by a jig, and vibration is applied to almost the center of the leaf spring to be measured, and the leaf spring is displaced in the vicinity of the jig. There is known a device for measuring a load variation caused by the load. There is also known a device that detects the load variation with a load sensor and electrically processes the variation.

In such a conventional device, it is effective when the vibration frequency is low (approximately 5 Hz or less) and the vibration amplitude is large (10 to 100 mm). Sufficient measurement cannot be performed for the characteristics when the amplitude is small. This causes a phase difference between the applied vibration and the response of the leaf spring for a high vibration frequency or a small vibration amplitude, so the load change amount at that time for the vibration amplitude at a certain time, that is, the displacement. This is because even if the measurement is made, it will not be an accurate measurement.

[0004]

In recent years, the design of leaf springs for automobiles has been required to accurately measure characteristics over a wide range of wide vibration amplitude and a wide range of vibration frequency. In order to compensate for this in the conventional device described above, instead of measuring the vibration amplitude, the vibration velocity, that is, the time differential value of the vibration amplitude is measured, and it is converted into the vibration amplitude by calculation, and at that time, the phase is approximated. Some devices have been devised. However, even if the vibration velocity is measured in place of the vibration amplitude, it cannot be accurately converted into the value of the vibration amplitude, so naturally there is a discrepancy between the actual value and the measurement calculation result. Therefore, the measurement accuracy becomes poor.

In order to measure the characteristics when the vibration frequency is high or when the vibration amplitude is large, it is conceivable to prepare different measuring devices, and when it is absolutely necessary, the characteristics are measured with two measuring devices. Then, the measurement result is corrected by calculation. However, in that case, it is not possible to obtain a continuous measurement result for the characteristics of one leaf spring, and the number of working steps is increased, so that a practical measuring device cannot be obtained.

[0006] The present invention has been made against such a background, and an apparatus capable of measuring the characteristics of a leaf spring over a wide range of vibration frequency and a wide range of vibration amplitude with one measuring device. The purpose is to provide. An object of the present invention is to provide an apparatus capable of accurately measuring the characteristics of an automobile leaf spring with a small number of steps.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for measuring the characteristics of a leaf spring in a wide range of amplitude and a wide vibration frequency range, and includes a base and an end portion of the leaf spring to be measured on the base. A jig for fixing the load, a vibration exciter for applying vibration between the base and the substantially central portion of the measured leaf spring, and a load applied to the measured leaf spring in the vicinity of the jig. A load sensor, a displacement sensor that detects the displacement of the leaf spring to be measured, and a means for measuring the load change amount of the load sensor with respect to the displacement detected by the displacement sensor. The displacement sensor is
Including displacement sensor for large amplitude and displacement sensor for small amplitude,
It is characterized in that it comprises a selecting means for selecting one of the outputs of the two displacement sensors according to the amplitude.

The selecting means detects the output phase difference of the two displacement sensors with respect to the control signal of the vibration exciter, a means for making the smaller output phase difference effective, and the vibration exciter. It is desirable to include means for respectively detecting the output phase difference of the two displacement sensors with respect to the control signal, and means for validating the outputs of the displacement sensors each having a predetermined value or less.

The large-amplitude displacement sensor and the small-amplitude displacement sensor of the present invention are relative, but as one guide, the large-amplitude displacement sensor is effective at an amplitude of 10 to 100 mm, and is small. Amplitude displacement sensor has an amplitude of 1-10m
It is effective in m.

[0010]

In the present invention, the large-amplitude displacement sensor and the small-amplitude sensor are attached to one leaf spring to be measured and used. Then, the one in phase with the exciter is effectively used. By doing so, the error in the measurement result due to the phase difference becomes small.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.

In the embodiment of the present invention, a base 1, a jig 3 for fixing an end portion of a leaf spring 2 to be measured to the base 1, and a base 1 are used.
And a load sensor 5 for detecting a load applied to the measured leaf spring 2 in the vicinity of the jig 3.
And a displacement sensor that detects the displacement of the leaf spring 2 to be measured, and a measuring unit 10 that measures the load change amount of the load sensor 5 with respect to the displacement detected by the displacement sensor. Further, as a feature of the present invention, the displacement is The sensor includes a large-amplitude displacement sensor 6a and a small-amplitude displacement sensor 6b,
The selecting means 8 is provided for selecting one of the outputs of the two displacement sensors 6a and 6b according to the amplitude.

The selecting means 8 includes means for detecting the output phase difference of the two displacement sensors 6a and 6b with respect to the control signal of the vibration exciter 4, and means for activating the smaller output phase difference. It includes means for detecting the output phase difference of the two displacement sensors 6a and 6b with respect to the control signal of the shaker 4, and means for validating the output of the displacement sensor 6a or 6b which is less than a predetermined value.

The measuring means 10 includes a digital signal processing device (DSP: Digi) which processes signals at high speed and with high accuracy.
tal Signal Processor) can be used.

Next, the operation of the embodiment of the present invention thus constructed will be described. FIG. 2 is a flow chart showing the flow of the measuring operation in the embodiment of the present invention.

Both ends of the measured leaf spring 2 are fixed to the jig 3, and vibration is applied by the vibrator 4 to the substantially central portion of the fixed measured leaf spring 2. The applied vibration has an amplitude of 1 to 100 mm and a frequency of 0 depending on the type of leaf spring 2 to be measured and the dynamic spring characteristic to be measured.
Given in the range of ~ 50 Hz. When the vibration starts to be applied, the measuring means 10 fetches and holds the value of the vibration signal when the operation becomes stable. Here, for example, the vertical movement is measured 10 times, and the measured value is converted into a digital signal to calculate an average value.

Next, the measuring means 10 fetches the signal detected by the large-amplitude displacement sensor 6a, for example, 10 times, and similarly converts it into a digital signal to calculate an average value. The trigger signal is applied at the position of level 0 of the vibration signal thus calculated, and the phase difference A (see FIG. 3) from the signal detected by the large-amplitude displacement sensor 6a is calculated. It is judged whether or not the calculated phase difference A is within 5 degrees, and if it is within 5 degrees, it is determined that the phase is in phase with the vibration exciter 4, and the signal detected by the load sensor 5 is taken in 10 times. , A digital signal is converted to calculate an average value, and a dynamic spring characteristic diagram for one frequency as shown in FIG. 4 is created. In the figure, the X axis shows the displacement signal and the Y axis shows the load signal.

If the phase difference is 5 degrees or more, the signal detected by the small-amplitude displacement sensor 6b is fetched, for example, 10 times, converted into a digital signal, the average value is calculated, and the excitation signal already calculated. Calculate the phase difference of. It is judged whether or not the calculated phase difference is within 5 degrees, and if it is within 5 degrees, it is determined that the phase is in phase with the vibrator 4, and the signal detected by the load sensor 5 is fetched 10 times to obtain a digital signal. It is converted into a signal and the average value is calculated, and similarly, a dynamic spring characteristic diagram for one frequency as shown in FIG. 4 is created.

By performing the measurement in this way and validating the one in phase with the vibration exciter 4, the error in the measurement result due to the phase difference becomes small.

[0020]

As described above, according to the present invention, it is possible to accurately measure the characteristics of the leaf spring with a small man-hour over a wide range of vibration frequency and a wide range of vibration amplitude with one measuring device. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of measurement operation in the embodiment of the present invention.

FIG. 3 is a diagram showing a phase difference between a vibration signal and a detection signal by a large-amplitude displacement sensor according to the embodiment of the present invention.

FIG. 4 is a diagram showing an example of dynamic spring characteristics according to the embodiment of the present invention.

[Explanation of symbols]

 1 unit 2 Leaf spring to be measured 3 Jig 4 Vibrator 5 Load sensor 6a Large-amplitude displacement sensor 6b Small-amplitude displacement sensor 8 Selection means 10 Measuring means

Claims (3)

[Claims] 1. A table, a jig for fixing an end portion of a measured leaf spring to the table, and a vibrator for applying vibration between the table and a substantially central portion of the measured leaf spring. A load sensor that detects a load applied to the measured leaf spring in the vicinity of the jig, a displacement sensor that detects a displacement of the measured leaf spring, and a load change of the load sensor with respect to a detected displacement of the displacement sensor. In a leaf spring characteristic measuring device having means for measuring an amount, the displacement sensor includes a large-amplitude displacement sensor and a small-amplitude displacement sensor, and one of the outputs of the two displacement sensors is determined according to the amplitude. A leaf spring characteristic measuring device comprising a selecting means for selecting. 2. The selecting means includes means for respectively detecting an output phase difference of the two displacement sensors with respect to a control signal of the vibration exciter, and means for activating the smaller output phase difference. Item 1. A leaf spring characteristic measuring device according to item 1. 3. The selecting means includes means for detecting an output phase difference of the two displacement sensors with respect to a control signal of the vibration exciter, and means for enabling an output of the displacement sensor which is a predetermined value or less. The leaf spring characteristic measuring device according to claim 1, further comprising: