JPH023432Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an impulse vibration device, and more particularly, to an improved impulse vibration device used in vibration tests on various mechanical structures.

[Conventional technology]

Conventionally, when testing the vibration characteristics of mechanical structures,
The method used was to attach a vibrator to a mechanical structure and excite it. In addition, in recent years, impact has been made using a so-called impulse hammer with a force-measuring pick-up attached to the tip of the hammer, the impact force has been measured, and the mechanical impedance has been measured based on the relationship between the force and the amount of vibration response. In addition, a simple analysis method has been developed and used, such as calculating the response mode using the reciprocity theorem.

In addition, as shown in Japanese Utility Model Application Publication No. 58-27750, it has been proposed that a connecting rod with a weight meter attached to the tip of an air hammer is disposed, and a vibrating head is provided on the connecting rod.

[The problem that the idea attempts to solve]

However, among the above three methods, although the method using a vibrator has high accuracy in measuring vibration characteristics, it is necessary to attach the vibrator to the test object. As a result, it may not be possible to mount the test piece, or it may be necessary to form a screw hole in the test specimen, making this method not an easy method. On the other hand, when using an impulse hammer, although the test can be easily carried out, it has the disadvantage that measurement accuracy deteriorates. As shown in FIG. 2, this is a structure in which the impulse hammer 1 is held in the hand and struck, so the pulse force is extremely small. In addition, since the force measuring pick-up 2 attached to the tip of the hammer directly hits the test piece 3, the tip of the pick-up and the surface of the test piece 3 to be hit come into contact at a point, causing plastic deformation and accuracy. The drawback was that it was not possible to measure force.

In addition, what is described in Utility Model Application Publication No. 58-27750 is
The connecting rod is struck by a piston, and the connecting rod moves and hits the test specimen. Since the piston and connecting rod do not work as one, there is a large energy loss, and there is no air vent hole, so high-speed operation is possible. Therefore, it was difficult to obtain a large excitation force. Furthermore, there were problems such as the test specimens being plastically deformed or damaged by collisions with the vibrating head.

[Means to solve the problem]

In order to achieve the above object, the impulse excitation device according to the present invention houses a striking mass body in a rigid cylinder, and has a through hole in the cylinder body connected to a compressed air source at a position where the striking mass body is housed. and an air vent hole in the lower part, and a contact protrusion that comes into contact with the test specimen is formed on the lower side of the lower end plate of the rigid cylinder that the striking mass collides with, and the contact protrusion is provided with an air vent hole in the lower part. The present invention is characterized in that a force detecting means is provided, and an operating lever is attached to the cylinder to push down the striking mass body and open the through hole. Preferably, the rigid cylinder is provided with a cylinder part made of an elastic body in the middle.

[Effect]

With this configuration, during testing, the contact protrusion is brought into contact with the test object, and the actuating lever is moved to slightly push down the striking mass. This downward movement of the striking mass opens the through hole, and compressed air is introduced into the upper chamber of the striking mass. As a result, the mass body falls due to the action of the compressed air and collides with the lower end plate of the cylinder, thereby applying a striking force toward the contact protrusion. Therefore, vibration characteristics tests can be performed by simply bumping the
It can be a simple and highly accurate test.

〔Example〕

FIG. 1 is a sectional view of an impulse excitation device according to an embodiment. As shown in the figure, this impulse vibration device has a rigid cylinder 10 in which a percussion mass 11 is housed. striking mass body 1
1 is suspended and supported by a spring 13 at the center of a lid 12 that closes the upper end surface of the cylinder 10, and is housed in the upper position of the cylinder 10 by the elastic force of the spring 13. Spring 13
is a state in which the striking mass body 11 is suspended, and the mass body 1 is
The mass body 11 is connected to and housed in the innermost part of the housing hole 14 formed in the mass body 11 so as to be housed inside the mass body 11 . However, when hitting upward, spring 1
3 is unnecessary. Further, a plurality of through holes 15 are bored along the circumferential direction in the upper part of the cylinder body 10A at the storage position of the striking mass body 11. An annular duct 16 is formed on the outer periphery of the cylinder body 10A at the position where the through hole 15 is formed, and compressed air is supplied to the duct 16. The supply source of compressed air is a compressor 17, and the compressed air generated by this compressor 17 is temporarily stored in a reservoir 18, and by connecting this reservoir 18 to the duct 16, compressed air can be supplied to the duct 16. ing.
In this case, the striking mass 11 is in a state of closing the through hole 15 when suspended by the spring 13, and compressed air from the duct 16 is not introduced into the cylinder 10 in this position.

Further, the rigid cylinder 10 has its cylinder body 10
A is divided into three parts, and includes an upper cylinder 19 in which the duct 16 is formed, and a lower cylinder 21 connected to the lower end of the upper cylinder 19 via an elastic cylinder 20. These are integrated by a flange connection.
The elastic cylinder 20 is a molded product made of hard rubber or the like, and is designed to moderate and absorb vibration propagation between the lower cylinder 21 and the upper cylinder 19. The lower end of the lower cylinder 21 is closed by an end plate 22, and a contact protrusion 24 is formed on the outer surface of the end plate 22 to abut against the impact point of the test specimen 23 and apply impact. are doing. The contact protrusion 24 has a smaller diameter than the cylinder body 10A,
It is a cylindrical projection with a striking force detection means 25 interposed therebetween for detecting the magnitude of the striking force. In addition, the contact surface of the contact protrusion 24 is provided with a specimen 2 at its center position.
It is also possible to form a space 27 that can surround the acceleration sensor 26 attached to the sensor 3 . In this case, the contact protrusion 24 can contact the test object 23 with the acceleration sensor 26 at the center position.

Note that the through holes 1 are formed along the circumferential direction in the lower part of the upper cylinder 19 and the lower part of the lower cylinder 21.
An air vent hole 28 similar to 5 is provided to allow internal air to be discharged to the outside when the striking mass body 11 falls. Further, an operating lever 29 is attached to the lid 12, which contacts the upper end surface of the striking mass body 11 and is capable of pushing down the mass body 11 against the spring 13.
The through hole 15 can be opened.

The action of the impulse excitation device configured in this way is as follows. When it is necessary to measure the acceleration at a vibrating point, the acceleration sensor 26 is first glued to the impedance measurement point. Next, the vibration device is brought into contact with the top of the acceleration sensor 26. At this time, the sensor 26 is accommodated in the space 27 of the contact protrusion 24, and the sensor 26 is arranged on the axis of the cylinder 10. The percussion mass 11 is located in the upper part of the cylinder body 10A by means of a spring 13. In this state, the through hole 15 is closed by the mass body 11,
The duct 16 and cylinder 10 are in a disconnected state.
Then, the compressor 17 is activated to store high-pressure compressed air in the reservoir 18, and the preparation is completed. The percussion action is initiated by pressing the actuating lever 29. That is, when the operating lever 29 is pressed, the striking mass 1
1 moves downward, the through hole 15 is opened, and the duct 16
and the cylinder 10 are brought into communication. In this state, compressed air flows from the reservoir 18 through the duct 16 into the cylinder 10 and is introduced into the chamber on the upper end side of the striking mass 11. As a result, the percussion mass 11 is accelerated under the action of compressed air, moves downwards and impinges on the end plate 22 of the lower cylinder 21 . At this time, the air in the cylinder chamber on the tip side of the mass body 11 flows out to the outside through the air vent hole 28, and does not become an obstacle to a collision. Then, the test object 23 is vibrated by the impact action of the mass body 11, the excitation force is detected by the impact force detection means 25, and the amount of acceleration of the test object 23 is detected by the sensor 26, so that the vibration characteristics can be measured. It is.

Note that during the above action, since the upper cylinder 19 and the lower cylinder 21 have an elastic cylinder 20 interposed between them, the transmission of the force due to the collision to the upper cylinder 19 is minimized, and the collision force is transmitted to the upper cylinder 19. To prevent inconveniences such as moving the main body.

As described above, according to this embodiment, since the collision action occurs on the lower cylinder 21 and the striking mass body 11,
Impact force detection means 25 arranged below the collision surface
can detect the true excitation force applied to the test object 23. Therefore, measurement accuracy is improved, and since collision deformation does not occur in the test body 23, the excitation force can be increased. Furthermore, the elastic cylinder 20
Because of this, the impact force is prevented from propagating to the entire device, and the impact force is transmitted only to the test body 23 side, which has the advantage of high impact efficiency.

[Effect of idea]

As described above, according to the present invention, since the air vent hole is provided in the lower part of the cylinder body, the striking mass body can be highly accelerated, and this striking mass body is integrated with the test specimen via the contact protrusion. Since the lower end plate of the cylinder is hit, not only does it generate a large excitation force, but it also does not cause plastic deformation or damage to the test specimen.

Therefore, the excellent effect of simplifying the structure and improving measurement accuracy is achieved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the impulse excitation device according to the present embodiment, and FIG. 2 is a diagram of a conventional impulse hammer in use. 10... Rigid cylinder, 11... Impact mass body,
13... Spring, 15... Through hole, 16... Duct,
17... Compressor, 18... Reservoir, 23
... Test object, 24 ... Contact projection, 25 ... Impact force detection means, 26 ... Acceleration sensor, 28 ... Air vent hole, 29 ... Actuation lever.

Claims (1)

[Claims for Utility Model Registration] 1. A percussion mass body 11 is housed in a rigid cylinder 10, and a through hole 15 connected to a compressed air source 17 is provided at the housing position of the percussion mass body 11 in the cylinder body 10A.
and an air vent hole 28 in the lower part, and a test specimen 2 is provided on the lower side of the lower end plate 22 of the rigid cylinder 10 against which the striking mass body 11 collides.
3, the contact projection 24 is provided with a striking force detection means 25, and the cylinder 10 is equipped with an operating lever 29 that pushes down the striking mass 11 to open the through hole 15. An impulse excitation device characterized by: 2. The impulse vibration device according to claim 1, wherein the rigid cylinder 10 has a cylinder body 20 formed of an elastic body in the middle thereof.