JPH10197501A - Automatic impact exciting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic impact exciting device which has good reproducibility of vibrational excitation and is free from occurrence of two-beat phenomenon. SOLUTION: A driven gear 2 is rotated by a driving gear 1, and a hammer 5 is drawn up through a spring 7 provided between the first arm 3 mounted on the driven gear 2 and the grip 5a of the hammer 5 which is installed coaxially with the driven gear 2 in such a way as rotatable independently, wherein the rotation of the hammer 5 is restricted by the second arm 4 furnished separately on the opposite side diametrically of the driven gear 2. When teeth of the driving gear 1 are set off from those of the driven gear 2, the hammer 5 is rotated in the exciting direction by the restitutive force of a spring 6 provided on the grip 5a of the hammer 5 or separately on the first arm 3, and before colliding with an object to be tested 10, the first arm 3 is hindered from rotating by a stopper 9. An alternative configuration may be adopted such that no arm is furnished on the driven gear and only one spring is used, a stopper of spring type is used instead to allow the hammer to run against it before collision with the object tested, or that a single arm is provided on the driven gear by furnishing a stopper on the driven gear.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic shock exciter, and more particularly to an automatic shock exciter used when a test object is excited in a vibration characteristic analyzer or the like.

[0001]

2. Description of the Related Art FIG. 9 schematically shows a configuration of a conventionally known vibration characteristic analyzing apparatus.
1 and an impulse hammer 22 for exciting the DUT 21 are prepared.

A force detecting sensor 23 is attached to the hammer 22, and a three-dimensional (x, y, z) of a vibration response caused by the vibration of the hammer 22 at an arbitrary position on the device under test 21.
An acceleration sensor 24 for detecting the acceleration in the direction is attached.

[0003] The output signal of the acceleration sensor 24 and the output signal of the force detection sensor 23 are given to the arithmetic unit 25 to perform FFT processing to obtain frequency response function data (FRF: compliance), and calculate mode characteristics. It has a configuration to output.

[0004] In this case, the vibration test is usually performed by using a hammer 22
The acceleration sensor 24 is sequentially moved to give a plurality of response functions to the arithmetic unit 25. The DUT 21 is fixed by a soft spring (not shown) or the like.

[0005] As described above, the impact excitation method using the impulse hammer is very effective and is widely used especially in a single product such as an engine block because of its small attenuation.

[0006]

However, when the person (operator) to be excited is different due to such an impulse hammer, the obtained frequency response also changes, and there is a problem that the reproducibility is poor. .

Therefore, an apparatus capable of automatically applying a reproducible shock is required. Such an automatic shock applying apparatus is disclosed in, for example, Japanese Utility Model Laid-Open Publication No. Sho 62-121544. is there.

Here, the pin provided on the rotating cam pushes down the handle of the hammer attached to the fixed shaft, whereby the head of the hammer is lifted, and the pin separates from the handle of the hammer, and at the same time, the weight of the hammer and the weight of the hammer. We have proposed an impact test device in which the hammer head is pulled down by the restoring force of a spring connecting the handle and each mounting part on the hammer stand.

[0009] However, in such a conventional example, since a single spring is used to pull the sample, the test object is hit again after the vibration, which is a so-called double hitting phenomenon. Had a major obstacle.

Accordingly, an object of the present invention is to eliminate the double tapping phenomenon in an automatic impact vibration device having reproducibility of vibration.

[0011]

[Means for Solving the Problems]

[1] In order to achieve the above object, an automatic shock exciter according to the present invention includes a drive gear having a gear attached only to a part of a circumference thereof, and a driven gear rotatably driven by the drive gear. An exciting hammer that can rotate coaxially independently of the driven gear, a first spring connected to generate a tensile load between a fixed end and a handle of the hammer, A first arm rotating with the gear, and a second spring having a larger spring constant than the first spring connected to generate a tensile load between the first arm and the handle of the hammer; A second arm provided on the opposite side of the diameter of the driven gear to rotate with the driven gear and restricting rotation of the hammer in the anti-exciting direction; Pulling the first spring when the teeth of the driven gear disengage from the teeth of the driven gear during shaking The hammer with the hammer by weight rotates in the direction excitation is characterized by comprising, abutting stopper protrusion of the first arm before vibrate the DUT.

That is, in the present invention, in a non-excited state in which the driving gear is not meshed with the driven gear, the driven gear and the first and second arms fixedly connected to the driven gear are separated from the driving gear. External force does not work because it is independent. Accordingly, the handle of the first arm and the hammer is pulled by the second spring, and the hammer hits the second arm and stops at that position.

The first spring attempts to return to its restored position, and the hammer whose handle is connected to the first spring is pulled by the first spring and stops at the restored position of the first spring.

In this restored position, since the first arm is prevented from rotating in the vibration direction by the stopper and the first spring is weaker than the second spring, the first spring does not return any further. To keep equilibrium.

In this state, when the driving gear is driven in the vibration direction, the driven gear 2 rotates in the counter vibration direction, and at the same time, the first and second arms rotate in the counter vibration direction. At this time, only the first spring is extended.

When the drive gear continues to rotate and its teeth are disengaged from the teeth of the driven gear, no external force acts on the driven gear, so the hammer, the two arms are restored by the restoring force of the first spring. , And the driven gear rotate in the vibration direction to return to the above-described equilibrium state, and the hammer attempts to collide with the DUT.

However, before the collision, the second arm provided on the driven gear hits the stopper, so that the rotation of the two arms and the driven gear is stopped. However, because the inertia acts on the hammer, the hammer collides with the DUT while extending the second spring.

The hammer moves in the anti-exciting direction due to the elastic force of the second spring and the inertial force of the hammer in the anti-exciting direction due to the collision, so that double hitting is prevented.

[2] Further, the automatic shock exciter according to the present invention provides the above-mentioned first spring of the present invention [1] in which the first spring is connected between the fixed end and the handle of the hammer. And the first arm are connected so as to generate a tensile load, and have a spring constant that does not have a specific magnitude relationship with the second spring.

That is, when the first spring is connected between the fixed end and the first arm in this way, in the non-excited state, the first spring is not at the position of the stopper but at the restored position of the first spring. Only the point of keeping the equilibrium state is different from the above-mentioned present invention [1]. At this time, it does not compete with the elastic force of the second spring and does not attract.

Therefore, in the vibrating state, the first arm pulls both springs, and rotates in the anti-vibration direction.

When the driving gear is disengaged from the tooth of the driven gear, the hammer, the two arms, and the driven gear rotate in the vibration direction to return to the above-mentioned equilibrium state by the restoring force of the first spring. Let me do.

At this time, since the first arm is rotated in the vibration direction beyond the restoring position of the first spring by inertia, it comes into contact with the stopper, and the rotation of the two arms and the driven gear is stopped. . However, since the inertia is still acting on the hammer, the hammer collides with the DUT while extending the second spring.

The elastic force of both springs and the inertia force of the hammer in the anti-excitation direction due to the collision causes the hammer to move in the anti-excitation direction, thereby preventing double hitting.

[3] Further, in order to achieve the above object, the automatic shock exciter according to the present invention further comprises a drive gear having only a part of a circumference on which a gear is attached, and a drive gear rotated by the drive gear. A driven gear to be driven, a vibration hammer having a handle fixed or integrated with the driven gear, and a spring connected to generate a tensile load between the fixed end and a handle of the hammer. When the teeth of the driving gear are disengaged from the teeth of the driven gear during vibration, the hammer rotates in the vibration direction due to the tensile load of the spring. And a spring stopper that abuts the handle.

That is, in the present invention, in the non-excited state where the driving gear is not engaged with the driven gear,
The hammer is pulled in the vibration direction by the spring and stops at the spring rest position. Since the spring stopper exists, the stop position can be the position of the spring stopper.

When the driving gear is driven and the driven gear is rotated in the anti-excitation direction, the handle of the hammer tends to rotate in the anti-excitation direction against the restoring force of the spring. When both gears are disengaged, the hammer is rotated in the vibration direction by the restoring force of the spring.

Before the hammer collides with the object to be vibrated, the handle of the hammer hits the spring stopper, and after the hammer hits the object to be tested by the inertial force, the returning force is exerted by the spring of the spring stopper, twice. Hitting is prevented.

[4] Further, in order to achieve the above object, the automatic impact vibration device according to the present invention comprises a drive gear having teeth only on a part of the circumference thereof, and a rotary gear driven by the drive gear. A driven gear to be driven, a vibration hammer that rotates coaxially with the driven gear, a first stopper fixed to the driven gear, and a coaxial rotation that is independent of the driven gear. Abuts against the first stopper and rotates together with the driven gear; a first spring connected to generate a tensile load between the arm and the fixed end; A second spring connected to generate a tensile load between the handle of the hammer and a tensile load of the first spring when teeth of the driving gear are disengaged from teeth of the driven gear during the excitation Causes the hammer to vibrate through the arm, the first stopper, and the driven gear. A second stopper which abuts on the arm before the hammer to vibrate the DUT when rotated in direction,
It is also possible to configure with.

That is, in the present invention, in the non-excited state where the driving gear is not meshed with the driven gear,
The hammer is pulled by the first spring via the arm, the first stopper, and the driven gear in the vibration direction, and stops at the spring return position. Since the second stopper exists, the stop position can be the position of the second stopper.

When the driving gear is driven, the driven gear is rotated in the anti-excitation direction, and the hammer is also rotated in the anti-excitation direction. When the driven gear rotates, the first stopper also rotates, so that the arm comes into contact with the first stopper and rotates in the anti-vibration direction against the tensile load of the first spring.

When both gears come off in the same manner as described above, the hammer is rotated in the vibration direction via the arm, the first stopper, and the driven gear by the restoring force of the first spring.

The arm hits the second stopper before the hammer collides with the object to be excited, but the hammer hits the object to be tested by inertia. After hitting the test object, the hammer is returned by the second spring provided between the handle and the arm, thereby preventing the hammer from hitting twice.

The arm can be provided with a protrusion, and the second spring is connected between a spring adjusting portion provided on the protrusion and a handle of the hammer, and the first spring is connected to the first spring. By providing the spring adjusting portion even at the fixed end to which the spring is connected, the restoring force of each spring can be adjusted, and thus the excitation speed of the hammer and the restoration speed after the excitation can be adjusted.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an automatic shock exciter according to the present invention, wherein 1 is a drive gear, and this drive gear 1 is connected to an AC motor as a power source. The rotation speed of the AC motor can be changed by converting the frequency of the AC power supply.

The drive gear 1 is a special gear in which only one to three teeth are left and other teeth are deleted. The drive gear 1 is meshed with a gear 2 having all the normal teeth. Have been.

Accordingly, since the gear 1 has only one to three teeth, when the gear 1 rotates, the driven gear 2 rotates about 30 ° at intervals of 5 seconds to 5 minutes.

Driven gear 2 driven by drive gear 1
, A first arm 3 and a second arm 4 are fixedly connected to each other on the opposite side of the diameter of the driven gear 2, and the rotating shaft of the impulse hammer 5 is connected to the rotating shaft of the gear 2. ,
These rotation axes are free to rotate with respect to each other.

The handle 5a of the hammer 5 is connected to a first spring 6 and a second spring 7, and the other end of the first spring 6 is fixed to a fixed end 8, and the second spring 7 The other end is arm 3
It is connected to the. Note that the spring constant of the spring 7 is larger than the spring constant of the spring 6, and an object having a large restoring force is selected.

The arm 4 rotates the handle 5a of the hammer 5 in the anti-vibration direction via the spring 7 by the arm 3 which is driven to rotate simultaneously with the rotation of the gear 2 by the gear 1. 5b is fixedly connected to the driven gear 2 so as to be regulated by contact with the driven gear 2b.

Reference numeral 9 denotes a stopper for preventing rotation of the arm 3 when the hammer 5 is vibrated toward the DUT 10 in the vibration direction.

The operation of the embodiment of such an automatic impact vibration device will be described below. First, in a non-excited state in which the gears 1 and 2 are not meshed, the gear 2 is in a free state independently of the hammer 5. At a standstill. The arm 3 and the hammer 5 are applied with a tensile load by the spring 7 in advance, and the hammer 5 and the arm 4 come into contact with each other and stop.

From such a state, the gear 1 is
Is driven, the arms 3 and 4 are rotated in the counterclockwise anti-vibration direction shown by the arrow B in the drawing, and the handle 5a of the hammer 5 is moved in the same direction B via the spring 7 accordingly. Since the hammer 5 is rotated, the hammer 5 rotates in the anti-excitation direction B.

When the teeth of the gear 1 are disengaged from the gear 2 as the rotational drive proceeds, the gear 2 is in a free state.
The hammer 5 rotates by a spring 6 in a vibration direction.

The hammer 5 rotates toward the DUT 10, but immediately before colliding with the DUT 10, the gear 2 rotates.
The arm 3 fixed to the gear 2 hits the stopper 9, and the gear 2 and the arms 3 and 4 are prevented from rotating.

However, since the inertia force is acting on the hammer 5, the hammer 5 continues the rotational movement against the force of the spring 7 and collides with the DUT 10.

Then, the inertia force of the hammer 5 is converted into a force in the opposite direction by this collision, and at the same time, the restoring force of the spring 7 (which is larger than the restoring force of the spring 6) acts, and the hammer 5 moves with the arrow B shown in the figure. By rotating quickly in the same direction,
You will be away from

Therefore, the hammer 5 is quickly separated from the DUT 10, thereby avoiding the double tapping phenomenon.

The exciting force can be adjusted by adjusting the two types of springs 6 and 7 connected to the gear 2. Furthermore, by adjusting the radius of rotation of the hammer 5 in the portion where the handle 5b of the hammer 5 is fixed, it is possible to adjust the momentum of the tip of the hammer 5.

FIGS. 2 and 3 show the relevance functions (coherence) when different persons respectively vibrate by hand with an impulse hammer. In this case, the test object is a ladder frame-like structure and a three-axis acceleration sensor is used, and therefore, the response point is in the X, Y, and Z directions of point 1.

In FIGS. 2 and 3 (1) to (3),
The relevance functions in the X, Y, and Z directions are shown, and the closer the relevance function is to “1”, the better the reproducibility of the data.

FIG. 4 shows a degree-of-association function when the automatic shock exciter according to the present invention shown in FIG. 1 is used. When the example of FIG. 4 is compared with FIGS. 2 and 3, the relevance function is “1”.
It can be seen that it is greatly improved near to. Especially 1KHz
It is shown that the improvement effect in the high frequency region described above is great.

When observing a change in the relevance function during the process of averaging eight times, the relevance function may significantly decrease during the process of averaging eight times when a person shakes. this is,
This is considered to be a phenomenon that occurs because the excitation direction and the excitation location are different from the others at that time.

In the case of the automatic impact vibration device, the device is stable and does not significantly decrease during the averaging process.

FIG. 5 shows the amplitude of the frequency response function when the same automatic shock excitation device according to the present invention is used.
When this is compared with the relevance function of FIG. 4, the relevance function is reduced only in the portion where the amplitude is as small as about 10 ^-3 and the noise is relatively clear in FIG.
In other parts, the relevance function is close to “1” and it can be said that there is reproducibility.

When a person vibrates, there is a portion where the relevance function is lower than "1" as shown in FIGS. 2 and 3 even in the portion where the amplitude is large and the noise is small in FIG. This indicates that there is data variation in this portion.

When a person vibrates, the actual vibration is performed after adjusting the amplifier by performing several test shots. At this time, make sure that the vibration direction and the vibration location are correct.
Vibration will be applied so as not to hit the ball. Also,
At the same time, care must be taken that the input voltage does not exceed the allowable voltage range.

Therefore, the impact excitation by a person requires great attention, and the mental burden also increases. As described above, the automatic shock exciter not only improves the relevance function, but also greatly reduces this mental burden.

FIG. 6 shows an embodiment in which the automatic shock exciter according to the present invention shown in FIG. 1 is modified. In this embodiment, a first spring 6 is fixed at a fixed end as shown in FIG. The difference is that the connection is made between the fixed end 8 and the first arm 3 instead of being connected between the handle 8 and the handle 5a of the hammer 5 instead. And this first
The spring constant of the spring 6 does not have a specific magnitude relationship with the spring constant of the second spring 7.

In the operation of this embodiment, in the non-excited state, only the restoring force of the spring 6 acts, so that an equilibrium state is maintained at the restored position of the spring 6.

When the vibration is applied, the arm 3 pulls both the springs 6 and 7 to rotate the hammer 5 in the anti-excitation direction B.

When the driving gear 1 is disengaged from the teeth of the driven gear 2, the hammer 5, two arms 3,
4 and the driven gear 2 are rotated in the vibration direction in order to return to the above-mentioned equilibrium state.

At this time, since the arm 3 is rotated in the vibration direction beyond the restoring position of the spring 6 due to inertia, it hits the stopper 9. At the same time, the rotation of the two arms 3 and 4 and the driven gear 2 is stopped. However, since the hammer 5 is engaged with the arms 3 and 4 only through the spring 7, the inertia still works, and the hammer 5 collides with the DUT while extending the spring 7.

Thereafter, the hammer 5 is pulled in the anti-vibration direction by the restoring force of the springs 6 and 7 and the inertia force of the hammer in the anti-vibration direction due to the collision, so that double hitting is prevented. Become.

FIG. 7 shows an embodiment in which the automatic shock exciter according to the present invention shown in FIG. 1 is separately modified. In this embodiment, arms 3 and 4 are provided on the driven gear 2. Without
The handle 5a of the hammer 5 is merely provided with a spring 6 between itself and the fixed end 8.

Instead, a spring stopper 11 is provided, in which a spring 11a is provided.

Accordingly, in the non-excited state in which the driving gear 1 is not meshed with the driven gear 2, the hammer 5 is pulled in the exciting direction by the spring 6, and the handle 5 b of the hammer 5 contacts the top of the stopper 11. It is stable in the state where it did

When the gear 1 is driven and the gear 2 is rotated in the anti-oscillation direction, the handle of the hammer 5 tries to rotate in the anti-oscillation direction B against the restoring force of the spring 6. Therefore, when the teeth of the driving gear 1 are disengaged from the teeth of the driven gear 2, the hammer 5 is rotated in the vibration direction A by the restoring force of the spring 6.

The handle 5 b of the hammer 5 contacts the spring stopper 11 immediately before the hammer 5 vibrates the DUT 10.

However, in this modification, the stopper 11 has the spring 11a, so that the rotation of the hammer 5 is decelerated, not stopped, due to the presence of the spring 11a.

Therefore, since the hammer 5 continues to rotate in a decelerated state, the DUT 10 is vibrated.

The spring 1 in the spring stopper 11
The hammer 5 is returned in the direction of arrow B by the repulsive force of 1a.

In this way, before the hammer collides with the object to be vibrated, the handle of the hammer 5 hits the spring stopper 11, and after the hammer 5 hits the object to be tested 10 by inertia, the spring 11a of the spring stopper 11 By
The return force acts to prevent double tapping.

In the embodiment shown in FIGS. 6 and 7, similarly, the relevance function and the frequency response function shown in FIGS. 4 and 5 are obtained.

FIG. 8 shows an embodiment in which the automatic impact vibration device according to the present invention shown in FIG. 1 is further modified. In this embodiment, the arm 4 is not provided on the driven gear 2, A stopper (first stopper) 12 is provided, and a spring (second spring) 7 is provided between the handle 5 a of the hammer 5 and the protrusion 3 a of the arm 3.

In a preferred embodiment, the projection 3a is provided with an adjusting screw 13 as a spring adjusting portion.
A spring 7 is provided between the adjusting screw 13 and the hammer handle 5a.
Is connected. Also, an adjustment screw 14 as a spring adjustment unit is provided at the fixed end 8 to which the spring 6 is connected. The spring 7 may be provided not between the handle 5a of the hammer 5 and the protrusion 3a but between the handle 5a and the arm 3 itself.

In operation, first, when the driving gear 1 rotates in the direction of arrow A, the driven gear 2 and the hammer 5 simultaneously rotate in the direction of arrow B.

At this time, the stopper 12 comes into contact with the arm 3,
The arm 3 also rotates in the direction of arrow B at the same time, and the spring 6 extends.

When the rotation proceeds and the teeth of the driving gear 1 are disengaged from the teeth of the driven gear 2, the arm 3, the stopper 12, the driven gear 2 and the hammer 5 are simultaneously directed to the DUT 10 by the restoring force of the spring 6. Rotate.

The arm 3 hits the stopper 9 before the hammer 5 vibrates the DUT 10, and the rotation of the arm 3 stops here.

However, the driven gear 2 and the hammer 5
Means that the rotation is continued in the vibration direction while the spring 7 is extended by the inertial force.

When the hammer 5 collides with the DUT 10, the inertia force of the former becomes a reverse force, and at the same time, the restoring force of the spring 7 also acts, so that the hammer 5 moves faster from the DUT 10 in the anti-excitation direction. Leave. As a result, hitting twice can be prevented.

In this case, the exciting speed of the hammer 5 can be adjusted by adjusting the adjusting screw 14, and the returning speed of the hammer 5 in the anti-exciting direction can be adjusted by adjusting the adjusting screw 13. be able to.

In the embodiment shown in FIG. 8, similarly, the relevance function and the frequency response function shown in FIGS. 4 and 5 are obtained.

[0085]

As described above, according to the automatic shock exciter according to the present invention, the driven gear rotates the driven gear, and the first arm provided on the driven gear, the driven gear, Pulls up the hammer via a spring provided between the handle of the hammer which is coaxial but rotates independently, and rotates the hammer by a second arm separately provided on the opposite side of the diameter of the driven gear. Regulating the teeth of the driving gear when the teeth of the driven gear are disengaged from the teeth of the driven gear.
Since the hammer is rotated in the vibration direction by the restoring force of a spring separately provided on the arm, the rotation of the first arm is prevented by the stopper before colliding with the DUT. Later, a spring that returns the hammer in the anti-excitation direction works,
Prevents double hits.

[0086] Further, since a spring for urging the elastic force in the return direction from the vibration point directly to the vibration hammer is not provided, a smaller spring is used as a spring in the vibration direction for raising the hammer. It will be a constant one.

Further, the above-mentioned arm is not provided on the driven gear, so that only one spring is used. Instead, the stopper is a spring-type one, and before the hammer collides with the DUT, the stopper is applied to the spring-like stopper. Even if it is configured to be in contact, it is possible to prevent the hammer from hitting twice.

Further, by providing the driven gear with a stopper, the driven gear can have only one arm.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an automatic impact vibration device according to the present invention.

FIG. 2 is a graph showing a relevance function of impact excitation by a person.

FIG. 3 is a graph showing a relevance function of impact excitation by a different person from FIG. 2;

FIG. 4 is a graph showing a relevance function of shock excitation by the automatic shock excitation device according to the present invention.

FIG. 5 is a graph showing an amplitude of a frequency response function by the automatic impact vibration device according to the present invention.

FIG. 6 is a schematic view showing a modified example of the automatic impact vibration device according to the present invention.

FIG. 7 is a schematic diagram showing still another modified example of the automatic impact vibration device according to the present invention.

FIG. 8 is a schematic view showing still another modified example of the automatic impact vibration device according to the present invention.

FIG. 9 is a block diagram illustrating a general configuration example of a vibration characteristic analysis device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive gear 2 Driven gear 3 Arm (1st arm) 3a Projection 4 Arm (2nd arm) 5 Hammer 5a Handle 5b Handle 6 Spring (1st spring) 7 Spring (2nd spring) 8 Fixed End 9 Stopper (second stopper) 10 DUT 11 Spring stopper 11a Spring 12 Stopper (first stopper) 13, 14 Adjustment screw In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Mitsuo Iwahara 8 Tosanabe, Fujisawa-shi, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. In-house (72) Inventor Kiichi Sasaki No. 8 Tsuchiya, Fujisawa-shi, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. (72) Inventor Akio Nagamatsu 2-12-1, Ookayama, Meguro-ku, Tokyo Tokyo Institute of Technology

Claims (5)

[Claims] 1. A driving gear having a gear attached only to a part of its circumference, a driven gear rotationally driven by the driving gear, and a vibrator capable of rotating coaxially independently of the driven gear. A hammer, a first spring connected to generate a tensile load between a fixed end and a handle of the hammer, a first arm that rotates with the driven gear, and the first arm. A second spring having a higher spring constant than the first spring connected so as to generate a tensile load between the first spring and the handle of the hammer;
A second arm provided on the opposite side of the diameter of the driven gear from the first arm to rotate together with the driven gear and restrict rotation of the hammer in the anti-excitation direction; When the teeth of the driving gear are disengaged from the teeth of the driven gear, the hammer rotates in the vibration direction due to the tensile load of the first spring. An automatic shock exciter, comprising: a stopper that abuts a protrusion of the first arm. 2. The method according to claim 1, wherein the first spring is not connected between a fixed end and the handle of the hammer, but a tensile load is generated between the fixed end and the first arm. And a spring constant having no specific magnitude relationship with the second spring. 3. A drive gear having a gear attached only to a part of its circumference, a driven gear rotationally driven by the drive gear, and a drive gear having a handle fixed or integrated with the driven gear. A swinging hammer, a spring connected to generate a tensile load between the fixed end and the handle of the hammer, and a spring when the teeth of the driving gear are disengaged from the teeth of the driven gear during excitation. An automatic impact vibration device comprising: a spring stopper that abuts on a handle of the hammer before the hammer vibrates the DUT when the hammer rotates in a vibration direction due to a tensile load. 4. A drive gear having teeth only on a part of the circumference thereof, a driven gear rotated by the drive gear, and a vibration hammer coaxially rotated with the driven gear. A first stopper fixed to the driven gear, an arm that rotates coaxially independently of the driven gear, but contacts the first stopper and rotates together with the driven gear; A first spring connected to generate a tensile load between the arm and the fixed end; a second spring connected to generate a tensile load between the arm and the handle of the hammer; When the teeth of the driving gear are disengaged from the teeth of the driven gear during excitation, the hammer causes the arm to move due to the tensile load of the first spring.
A second stopper that abuts on the arm before the hammer vibrates the DUT when rotated in the vibration direction via the first stopper and the driven gear. Automatic shock exciter. 5. The arm according to claim 4, wherein the arm has a projecting portion, and the second spring is connected between a spring adjusting portion provided on the projecting portion and a handle of the hammer. An automatic shock exciter characterized in that a spring adjusting portion is provided even at a fixed end to which one spring is connected.