JPH02304331A - Torsional dynamic property testing machine - Google Patents

Abstract

PURPOSE:To perform an exact measurement without using a rigid frame by setting a resonance frequency determined by mass of a mass member side and a spring constant of each elastic body so as to become smaller than a frequency of a torsion dynamic load. CONSTITUTION:Mass of mass members 22a, 22b side and a spring constant of each elastic body 21, 21 are set so that a resonance frequency determined by mass of the mass members 22a, 22b side supported through each elastic body 21, 21 on a fixed frame 20b and a movable frame 20c, and the spring constant of each elastic body 21, 21 becomes smaller enough than a frequency of a torsion dynamic load generated by a torsion actuator 23. In such a way, even if a frequency of the torsion dynamic load applied by the torsion actuator 23 to a specimen 27 connected between the torsion actuator 23 and a torque detector 24 is high, it does not occur that the fixed frame 20b and a common frame 20a are vibrated by the torsion dynamic load applied to the specimen by the actuator 23 and its reaction force, and displacement of the torsion actuator 23 and the torque detector 24 can be eliminated substantially.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention applies a torsional dynamic load to a test specimen made of an elastic material such as a rubber coupling or a damper pulley used in automobiles, etc., to determine the spring constant and loss. This relates to a torsional dynamic characteristic testing machine that tests dynamic characteristics such as coefficients.

[Conventional technology]

This type of testing machine has a test specimen and a torque detector set in series with the output shaft of a torsional actuator that generates a torsional dynamic load that repeats in forward and reverse directions. This method is used to determine the loss coefficient and spring constant of the test specimen from the equation of motion based on the angle, torsion speed, etc.

Conventionally, in this type of testing machine, as shown in FIG. 7, a fixed pedestal 2a and a movable pedestal 2b are placed facing each other on the upper surface of a common pedestal 2 which is installed on a foundation B such as the ground via an air spring 1. The output shaft 3a of the torsion actuator 3 fixed to the fixed pedestal 2a and the torque detector 4 fixed to the movable pedestal 2b are connected to a rotating side flange 5 having a connecting fitting 5a made of a chuck or the like, and a connection made of a chuck or the like. Attach the fixed side flange 6 having the metal fittings 6a, respectively,
Both ends of the specimen 7 are gripped by the connecting fittings 5a and 6a, respectively.

Further, the torsional angle of the output shaft 3a of the torsional actuator 3 is detected by an angle detector 8 attached to the torsional actuator 3.

Note that 9 is an operation handle for moving the movable pedestal 2b in the direction of the arrow when fixing the test specimen 7 between the chucks 5a and 6a.

In the above configuration, the rotating side flange 5 is reciprocated and rotated by the torsion actuator 3 to
10 to 5007 repeated torsional loads (torsional dynamic loads)
However, at this time, the torque detector 4 or the angle detector 8
By servo-controlling the servo valve 3b of the torsion actuator 3 using the load signal or torsion angle signal as a feedback signal, a predetermined load or twist of a predetermined angle is applied to the test specimen 7.

At this time, the torsional dynamic characteristics of the test body 7 are tested by processing data regarding the load applied to the test body 7 and the torsional angle detected by the torque detector 4 and the angle detector 8, respectively. I can do it.

[Problem to be solved by the invention]

By the way, in the above-mentioned test machine, in order to accurately determine the loss coefficient and spring constant, the torsion actuator 3 and torque detector 4 installed on the pedestal 2 must not be displaced relative to each other. The structure must be formed with a certain level of robustness.This method of handling can be applied while the repetition frequency of the torsional dynamic load applied by the torsional actuator 3 is low, but as the frequency increases, the frame 2 will resonate. Become.

For this reason, a relative displacement occurs between the torque detector 4 fixed to the movable frame 2b and the torsional actuator 3 fixed to the fixed frame 2a, and accurate torsional torque measurement is prevented. It becomes impossible to perform highly accurate dynamic characteristic tests.

Furthermore, if an attempt was made to make the mount sturdy to prevent this from happening, the testing machine would become extremely large and expensive.

Therefore, in view of the above-mentioned points, the present invention provides a torsional dynamic characteristic testing machine that does not become large or expensive even when performing a dynamic characteristic test by applying a torsional dynamic load of a relatively high frequency. The challenge is to provide this.

[Means to solve the problem]

In order to solve the above problems, a torsional dynamic characteristic testing machine made according to the present invention includes two mass members each placed on a stand via an elastic body, a torsional actuator fixed to one of the mass members, and a torsional actuator fixed to one of the mass members. a torque detector fixed to the other mass member, the torsion actuator applies a torsional dynamic load to the test specimen connected between the actuator and the torque detector, and the test piece is supported via each of the elastic bodies. The mass on the mass member side and the spring constant of each of the elastic bodies are set so that the resonance frequency determined by the mass on the mass member side and the spring constant of each of the elastic bodies is sufficiently smaller than the frequency of the torsional dynamic load by the torsional actuator. It is characterized by what it did.

[For production]

In the above configuration, the mass member side is adjusted such that the resonance frequency determined by the mass of the mass member side supported through each elastic body and the spring constant of each elastic body is sufficiently smaller than the frequency of the torsional dynamic load caused by the torsional actuator. Since the mass and the spring constant of each elastic body are set, even if the frequency of the torsional dynamic load applied by the torsional actuator to the test specimen connected between the actuator and torque detector is high, the mount will not be able to handle the torsional load applied to the specimen by the torsional actuator. It is not vibrated by torsional dynamic loads and their reaction forces, and it is possible to accurately measure torsional torque and perform highly accurate dynamic characteristic tests without having to make the stand rigid.

〔Example〕

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

FIGS. 1 to 4 show an embodiment of a torsional dynamic characteristic testing machine according to the present invention, but before going into a description of the embodiment, the technology underlying the present invention will be explained.

By the way, as shown in Fig. 5, the elastic body K in the spring constant
In a vibration system in which an object M of mass m is supported on a foundation B via a foundation B, when a periodic external force acts on the object M,
As shown in Figure 6, the amplitude T of the external force and the frequency f of the vibration are
As the frequency increases, it approaches zero.

In Fig. 6, the point where the amplitude T is the largest is
This is the point where the frequency f of the external force and vibration coincides with the natural frequency f0 of the vibration system and resonance occurs.

Above f. is expressed as J k /m, so if k of the elastic body is made small and m of the object M is made large, the above-mentioned peak point can be moved to a lower frequency. In addition, in FIG. 6, where T becomes smaller than 1,
γ decreases at a rate of -40 dB/dec. In other words, when the frequency r increases by 10 times, γ becomes 1/10
becomes 0. Therefore, even if the frequency f is not so high, a vibration system in which displacement of the object M is substantially eliminated can be obtained.

In the test machine shown in Figs. 1 to 4, which was created based on the above-mentioned technical idea, 20 in the figure is a foundation (not shown).
The mount 20 is a mount installed on the common mount 2.
A fixed pedestal 20b is fixedly provided on the upper surface of one end of Oa, and a movable pedestal 20C is provided on the upper surface of the other end so as to be movable relative to the fixed pedestal 20b. On the upper surfaces of the fixed pedestal 20b and the movable pedestal 20c, mass members 22a and 22b are respectively installed via four elastic bodies 21 each made of, for example, an air spring. Part 2
A torque detector 24 is fixed to each of 2b.

A rotating side flange 25 having a connecting fitting 25a made of a chuck or the like is attached to the output shaft 23a of the torsional actuator 23, and a stationary side flange 26 having a connecting fitting 26a made of a chuck or the like is attached to the torque detector 24. Both ends of the test specimen 27 are gripped by the connecting fittings 25a and 26a of the flanges, respectively.

Further, the torsional angle of the output shaft 23a of the torsional actuator 23 is detected by an angle detector 28 attached to the torsional actuator 23. In addition, 29 is a connecting fitting 25a
This is an operation handle for moving the movable pedestal 20c in the direction of the arrow when fixing the test specimen 27 between the test body 27a and 26a.

FIG. 3 shows an example of the installation structure of the mass members 22a and 22b using air springs 21 as elastic bodies on the fixed pedestal 20b and the movable pedestal 2Oc.
The mass members 22a, 22b are placed on the mass members 22a, 20c, and the air spring 21 is attached to the mass members 22a, 22b with bolts 21b, so as to restrict movement of the mass members 22a, 22b in the planar direction.

FIG. 4 shows an example of the configuration of the torque detector 24, in which a pair of arms 26b are extended radially from substantially symmetrical positions on the fixed flange 26, and a piezoelectric voltage is applied between the arms 26b and the convex portion 22b' of the mass member 22b. interposing elements 24a and 24b, respectively;
When the fixed flange 26 is rotated left and right as shown by arrows in the figure, it outputs an electric signal corresponding to the magnitude of the load alternately applied to the piezoelectric elements 24a and 24b.

In the above configuration, the rotating side flange 25 is reciprocated and rotated by the torsional actuator 23 to apply a repeated torsional load of 10 to 500) (z) to the test specimen 27. At this time, the torque detector 24 or the angle detector 28
By servo-controlling the servo valve 23b of the torsion actuator 23 using the load signal or torsion angle signal from as a feedback signal, a predetermined load or twist of a predetermined angle is applied to the test specimen 27. At this time, the torsional dynamic characteristics of the test body 27 are tested by processing data regarding the load applied to the test body 27 and the torsional angle detected by the torque detector 24 and the angle detector 28, respectively. I can do it.

As described above, the elastic body 21 and the mass member 22a installed on the fixed frame 2Ob function as one vibration system that receives the reaction force of the torsional dynamic load by the torsional actuator 23, and as described above with reference to FIG. By appropriately selecting the mass of the member 22a and the spring constant of the elastic body 21, the torsional dynamic load caused by the torsional actuator 23 can be reduced without making the fixed pedestal 20b and the common pedestal 20a that support the torsional actuator 23 very strong. in frequency,
Displacement of the mass member 22a and the torsion actuator 23 fixed to the mass member 22a can be substantially eliminated.

On the other hand, the elastic body 21 and the mass member 22b installed on the movable frame 2Oc function as a vibration system in which vibration is applied by the torsion actuator 23 via the test body 27.
In this case as well, as described above with reference to FIG. 5, by appropriately selecting the mass of the mass member 22b and the spring constant of the elastic body 21, the mass member 22b and the mass member 22b
Displacement of the torque detector 24, which is fixed to the position, can be substantially eliminated.

In the illustrated embodiment, the fixed frame 20b and the mass member 22
a, and between the movable pedestal 20c and the mass member 22b, fastening cylinders 30 are respectively provided. By directly connecting the frame and the mass member, the function of the elastic body can be nullified, and resonance caused by the mass member and the elastic body can be prevented.

〔effect〕

As explained above, according to the present invention, even when the frequency of the torsional dynamic load applied by the torsional actuator to the test specimen connected between the actuator and the torque detector is high, the mount can handle the torsional dynamic load applied to the specimen by the torsional actuator. Moreover, since it is not vibrated by the reaction force, accurate torsional torque measurement and highly accurate dynamic characteristic tests can be performed even if the mount is made robust.

[Brief explanation of drawings]

1 and 2 are front and top views respectively showing an embodiment of the torsional dynamic characteristic testing machine according to the present invention, and FIGS. 3 and 4 are detailed examples of parts of FIGS. 1 and 2. FIG. 5 and FIG. 6 are explanatory diagrams for explaining the technical idea that is the principle of the present invention, and FIG. 7 is a diagram showing an example of a conventional testing machine. 20... mount, 20a... common mount, 20b...
Fixed pedestal, 20c... Movable pedestal, 21... Elastic body,
22a, 22b... Mass member, 23... Torsional actuator, 24... Torque detector, 27... Test object. Patent applicant Saginomiya Seisakusho Co., Ltd. b B Figure 7

Claims (1)

[Scope of Claims] Two mass members each placed on a frame via an elastic body, a torsion actuator fixed to one of the mass members, and a torque detector fixed to the other mass member. , a torsion actuator applies a torsional dynamic load to the test specimen connected between the actuator and the torque detector, and the mass of the mass member supported via each of the elastic bodies and the spring of each of the elastic bodies A torsional dynamic characteristic testing machine characterized in that the mass on the mass member side and the spring constant of each of the elastic bodies are set so that a resonance frequency determined by the constant is sufficiently smaller than a frequency of a torsional dynamic load by the torsional actuator.