JPH06265438A - Vibration tester - Google Patents

Abstract

PURPOSE:To provide a multidimensional simultaneous excitation that has a high exciting band and, what is more, two or three directions are made excitable by making up a triaxial minute vibro-exciter which sets up a piezoelectric actuator orthogonally in two or three directions and transmits each individual displacement to respective existing blocks without entailing any interference. CONSTITUTION:In this tester, aix is X direction input acceleration, vix is X direction input measure and dix X direction input displacement respectively, and any input is possible to be done. Likewise, aox is the acceleration output of an X direction acceleration sensor 7x, vox is speed output and dox displacement output respectively. A deviation of each input-output is operated by each add circuit, thereby performing its feedback control. With this constitution, a nonlinear characteristic of hysteresis or the like of a piezoelectric element is compensated, and highly accurate excitation is thus performable. As for an exciting method, those of X direction acceleration aix, Y direction acceleration aiy and Z direction acceleration aiz of service acceleration are detected by the acceleration sensor, and these detected values are inputted into a virbo- tester, whereby a regenerative test of the service acceleration can be done in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration tester for evaluating the vibration characteristics of a test piece, and more particularly to a multidimensional vibration capable of simultaneously exciting in two or three directions and up to a high frequency of several tens of kHz. Regarding test equipment.

[0002]

2. Description of the Related Art In order to evaluate the vibration characteristics of mechatronic products and parts, a vibration test using a vibrating device is indispensable. Moreover, since the vibration characteristics of the test piece generally differ depending on the vibration direction, the demand for a vibration device capable of simultaneously vibrating in two or three directions is increasing.

An example of the mechatronic parts is a head support system of a magnetic disk device. Acceleration in the seek direction from the carriage is mainly applied to the head support system, but disturbances from the bearing and the like are also applied from the roots in other directions. In the case of a large-sized magnetic disk device, a linear actuator is currently the mainstream, and the longitudinal direction of the load arm is the seek direction. Further, in the case of a small magnetic disk device, an in-line system, which is a rotor reactor and has a seek direction perpendicular to the longitudinal direction of the load arm, is the mainstream. In particular, it is being adopted along with the tendency of downsizing. Therefore, as the support system evaluation shaker, it is desirable to use a device which is capable of independent vibration in XYZ triaxial equality in consideration of various working conditions.

The most common conventional vibration device is an electromagnetically driven so-called voice coil motor type, and a typical example of the structure as a two-way vibration device is shown in FIG. In the figure, 101 is a fixed part, which is a magnet (electromagnet or permanent magnet) 102x and Y driven in the X direction.
A direction-driving magnet 102y is provided. The coils 103x and 103y are driven by the respective magnets. Reference numeral 104 denotes a movable part on which a sample is installed, which is driven by the coils 103x and 103y via means 105x and 105y such as bearings.

[0005]

However, the electromagnetically driven multidimensional oscillating device described above has a problem that the structure is complicated and that the oscillating band cannot be increased and the frequency is limited to several kHz or less. That is, like some mechatronic parts in recent years (for example, a head support mechanism of a magnetic disk device), 10 kHz.
It cannot be applied when the above vibration characteristics evaluation is required.

Therefore, an object of the present invention is to provide a multi-dimensional vibration test apparatus capable of multi-dimensional simultaneous vibration in two directions or three directions and a vibration band of 10 kHz or more.

Another object of the present invention is to provide a simulator capable of reproducing the actual working acceleration so that the behavior of parts during the operation of a mechatronic product (for example, a magnetic disk device) can be simulated.

[0008]

The above object is to provide a triaxial micro actuator in which piezoelectric actuators are orthogonally arranged in two directions or three directions, and displacements of the respective actuators are transmitted to a vibration block at the tip end without interfering with each other by a displacement synthesizing member. This is achieved by constructing a vibration exciter.

Further, the actual acceleration of the mechatronics product (for example, a magnetic disk device) during operation is measured by an acceleration sensor, and the acceleration signal is input to the three-axis microvibration vibrating device through a double integration circuit. The above object is achieved by a simulator that reproduces.

[0010]

With the above construction, it is possible to simultaneously perform high-bandwidth excitation in two or three directions with respect to the test piece, and also to provide high incoherence. Furthermore, it is possible to accurately reproduce the acceleration input.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a block diagram of a multidimensional vibration test apparatus according to a first embodiment of the present invention. Reference numeral 1 is a main body of a triaxial exciter capable of vibrating in three orthogonal directions, 2 is a base, 3a, 3b and 3c are piezoelectric actuators composed of laminated piezoelectric elements arranged orthogonally to the base 2, and 4 is a tip of the vibrator. Specimen (not shown) For example, dimensions required to support and fix (screw) the load arm of the head support system for the magnetic disk device (several millimeters)
Cube-shaped movable block with about 10 mm), 5
Reference numerals a, 5b, 5c are elastic hinge mechanisms as displacement synthesizing members for connecting the laminated piezoelectric elements 3a, 3b, 3c and the movable block 4 and for avoiding interference of displacement in the other direction.

The laminated piezoelectric elements 3a, 3b, 3c
Is firmly fixed by bonding or bolting between the coupling plates 6a, 6b, 6c provided at the other end of the elastic hinge mechanism and the base 2. Further, the base 2 is sufficiently heavier than the movable block 4 (for example, mass ratio 1: several tens or more) to make it less susceptible to the vibration of the tip.

An X-direction acceleration sensor 7x of the movable block 4 is attached to detect the output acceleration during vibration. Y
Illustration of the acceleration sensor in the Z direction and the Z direction is omitted.

As for the drive and control circuit, only one axis in the X direction is shown. Although illustration of the Y direction and the Z direction is omitted, the configuration is the same as the X direction. Reference numeral 8 is a drive amplifier for driving the laminated piezoelectric element 3a, and 9a, 9b, 9
Reference numerals c and 9d are integrating circuits and 10a, 10b and 10c are adding circuits.

FIG. 2 shows a first embodiment of the movable block which constitutes the present invention, and shows the details of the movable block 4 and the elastic hinge mechanisms 5a, 5b, 5c. Each of the elastic hinge mechanisms 5a, 5b, 5c is composed of a four-column elastic hinge having notches at both ends, has high rigidity in the axial direction of the column, and has a flexible structure in two directions orthogonal to the axis of the column. Therefore, the displacements of the piezoelectric elements in the three directions can be transmitted to the movable block at the tip with less mutual interference.

FIG. 3 shows a coupling structure of the movable block and the base constituting the present invention shown in FIG. 2, in which the laminated piezoelectric elements 3a, 3b and 3c are bolted to the elastic hinge mechanism 5a. The method of fixing between 5b and 5c and the base 2 is shown in a partial cross section. In the case of bolting, through holes are formed in the laminated piezoelectric elements 3a, 3b, 3c by ultrasonic machining, and the bolts 11 are penetrated to connect the coupling plates 6a, 6b, 6c of the elastic hinge mechanism section and the base 2 to each other. Firmly fix.

Next, the operation of the above-described first embodiment of the present invention will be described.

In FIG. 1, aix is the X-direction input acceleration, vix is the X-direction input velocity, and ix is the X-direction input displacement, and any input is possible. Also, aox is X
The acceleration output of the directional acceleration sensor 6x, vox is a velocity output, and dox is a displacement output. The deviation between each input and output is calculated by each addition circuit to perform feedback control. By this feedback control, nonlinear characteristics such as hysteresis of the piezoelectric element can be compensated, and highly accurate vibration can be performed. As the vibration method, for example,
Acceleration ai in the X direction of the actual work acceleration generated in the actual device
By detecting the x, Y-direction acceleration aiy, and the Z-direction acceleration aiz by an acceleration sensor and inputting them into the multidimensional vibration test apparatus of the present invention, a reproduction test of the actual acceleration can be performed. Further, when the vibration of the object is measured by the laser-Doppler measuring device, a speed signal is obtained. In this case, the vibration state of the actual machine is input by inputting the X-direction speed vix, the Y-direction speed viy, and the Z-direction speed viz. Can be reproduced.

In the above-mentioned embodiment, the feedback control structure is adopted for performing highly accurate vibration. However, if the above feedback signal is not used and open control is performed, a simple and inexpensive vibration system can be provided. Can be configured.

FIG. 4 shows an example of the vibration performance result of the first embodiment of the multidimensional vibration testing apparatus of the present invention, showing the frequency characteristics of each acceleration when one axis is vibrated. In this example, each axis acceleration is shown when the x-axis is excited by a sine wave excitation with a constant displacement amplitude (that is, a constant voltage amplitude) under open control without feedback. The vertical axis represents the generated acceleration a (G) per applied voltage V in dB, that is, 20 log (a / V), and 0 dB = 1 G / V. As a result, 10kH
It has a sufficient excitation band up to z and -20 dB or less (that is, 1/10 or less in the other direction with respect to the main excitation direction) for each axis, and achieves nearly three-axis independent excitation performance. There is.

FIGS. 5 and 6 are views showing a second embodiment of the device of the present invention, in which the vibration band and the non-coherence of the first embodiment are further improved. 5 and 6, the same reference numerals as those in FIG. 1 represent the same parts. 14
Is a movable block, and the dimension u of one side is set to the piezoelectric elements 3a, 3c.
The width is reduced to be smaller than the width w to reduce the mass. 15
a, 15b, 15c are elastic hinge mechanisms, and their width dimension v
Is approximately equal to the width u of the movable block 14 and is therefore smaller than the width w of the piezoelectric element. 6a,
Reference numerals 6b and 6c are coupling plates provided at the other end of the elastic hinge mechanism, and are coupled to the piezoelectric elements 3a, 3b and 3c by means such as adhesion.

The width of the coupling plate may be smaller than the width w of the piezoelectric element as shown in the drawing. Further, a sample 17 such as a load arm of a head supporting system for a magnetic disk device is attached to the movable block 14 with a screw 18
It has a structure that can be fixed by.

Next, the effect of the second embodiment of the apparatus of the present invention described above will be explained.

FIG. 7 schematically shows changes in the posture of the movable block 4 when the Z-direction piezoelectric element 3c is displaced by δ in the first embodiment of the present invention. The z-direction piezoelectric element 3c receives a bending moment and tilts due to a reaction force F0 from the elastic hinge mechanism in the other direction, and as a result, the movable block 4 tilts by an angle θ and rotates about the Y-axis with respect to the Z-axis driving direction (yaw). Ing) occurs. Similarly, rotation around the X axis (pitting) also occurs. Further, the non-coherence of vibration is deteriorated. Therefore, reduction of the rotational component becomes a problem for more accurate vibration.

FIG. 8 schematically shows a change in posture of the movable block 14 when the Z-direction piezoelectric element 3c is displaced by δ in the same manner as described above in the second embodiment of the device of the present invention. . In this case, the reaction force F0 from the elastic hinge mechanism in the other direction is applied near the center of the Z-direction piezoelectric element 3c, so that the movable block 14 can be translationally driven without tilting. Therefore, it is possible to remove the rotational component associated with the vibration and significantly improve the non-coherence. According to the second embodiment of the present invention, it is possible to realize an excitation band of 15 kHz or more and a non-coherence of -40 dB or less.

9 and 10 show a third embodiment of the device of the present invention. In these figures, the same symbols as those in FIGS. 5 and 6 are the same parts. Base 2 in this embodiment
Of the back metal 21a, 21b, and 21c, which are respectively divided and bonded to the piezoelectric elements 3a, 3b, and 3c, and the main base 22. In the embodiment shown in FIGS. 5 and 6, since the base 2 and the elastic hinge mechanism are integrally formed, when assembled and bonded, the bonding thickness varies depending on the processing accuracy of each component, and as a result, the vibration of the vibration exciter is generated. There may be variations in characteristics or the vibration performance may deteriorate. On the other hand, in this embodiment, the coupling plates 16a, 16b, 16c, the piezoelectric elements 3a, 3b, 3c, and the back metals 21a, 21b, 21c are separately bonded by a predetermined jig or the like, and then the bolts 23a. , 2
Since it is fixed to the main base 22 by fixing means such as 3b and 23c, the adhesive layer becomes uniform and strong, and the vibrating device having stable performance and high reliability can be provided.

[0028]

According to the present invention, there is provided a multi-dimensional vibration test apparatus having a vibration band of 10 kHz or more and capable of performing multi-dimensional simultaneous vibration in two or three directions and having excellent independent vibration performance. can do.

Further, it is possible to provide a simulator capable of reproducing the actual working acceleration so that the behavior of parts during the operation of a mechatronic product (for example, a magnetic disk device) can be simulated.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a first embodiment of a vibration test apparatus of the present invention.

FIG. 2 is a perspective view of a movable block constituting a first embodiment of the device of the present invention shown in FIG.

FIG. 3 is a front view showing, in a partial cross-section, a connecting structure of a movable block and a base which constitutes the first embodiment of the device of the present invention shown in FIG.

FIG. 4 is a characteristic diagram showing an example of vibration performance results in the first embodiment of the vibration test apparatus of the present invention.

FIG. 5 is a front view of a second embodiment of the vibration test apparatus of the present invention.

FIG. 6 is a plan view of the second embodiment of the vibration test apparatus of the present invention shown in FIG. 5, viewed from the line VI-VI.

FIG. 7 is a diagram schematically showing the posture change of the movable block when the piezoelectric element is displaced in the first embodiment of the device of the present invention.

FIG. 8 is a diagram schematically showing a posture change of the movable block when the piezoelectric element is displaced in the second embodiment of the device of the present invention.

FIG. 9 is a front view of a third embodiment of the device of the present invention.

FIG. 10 shows a third embodiment of the device of the invention shown in FIG.
It is the top view seen from X-ray.

FIG. 11 is a front view showing a configuration of a conventional multidimensional vibration test apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 3-axis vibration exciter, 2 ... base, 3a, 3b, 3c ... piezoelectric actuator, 4, 14 ... movable block, 5a, 5
b, 5c, 15a, 15b, 15c ... Elastic hinge mechanism,
6a, 6b, 6c, 16a, 16b, 16c ... Coupling plate, 7x ... Acceleration sensor, 8 ... Drive amplifier, 9a, 9
b, 9c, 9d ... Integrator circuits, 10a, 10b, 10c ...
Adder circuit, 17 ... Specimen, 21a, 21b, 21c ... Back metal, 22 ... This base.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Takahashi 2880, Kozu, Odawara-shi, Kanagawa Stock Company Hitachi Storage Systems Division

Claims (8)

[Claims] 1. A vibration test apparatus capable of vibrating a specimen in multiple directions, for supporting and fixing a piezoelectric actuator arranged in orthogonal biaxial or orthogonal triaxial directions, a base for supporting them, and a specimen. A vibration test apparatus comprising a movable block and an elastic hinge mechanism having one end coupled to the movable block and the other end coupled to a coupling plate to avoid interference with displacement in the other direction. 2. The elastic hinge mechanism of each shaft comprises a four-column elastic hinge having notches at both ends, has high rigidity in the axial direction of the column, and has a flexible structure in two directions orthogonal to the axis of the column. 2. The vibration test apparatus according to claim 1, wherein displacements of the piezoelectric actuators in three directions are transmitted to the movable block at the tip while reducing mutual interference. 3. The vibration test apparatus according to claim 1, wherein the movable block, the elastic hinge mechanism of each shaft, and the coupling plate of each shaft have an integral structure. 4. The vibration test apparatus according to claim 1, wherein the piezoelectric actuator is fixed by a bolt between a coupling plate of the elastic hinge mechanism section and a base. . 5. The vibration test apparatus according to claim 1, wherein the dimension of one side of the movable block and the width of the elastic hinge mechanism portion are smaller than the width dimension of the piezoelectric element. . 6. The piezoelectric element according to claim 1, wherein a coupling plate is bonded to one end of each piezoelectric element, and a back metal is bonded to the other end thereof, and the back metal is fixed to the main base by a fixing means such as a bolt. The vibration test apparatus according to any one of 5 above. 7. An acceleration signal from an acceleration input terminal is input to a drive amplifier via a double integration circuit to drive the piezoelectric actuators of the respective axes, and a movable block is provided with acceleration sensors of the respective axes. The vibration test apparatus according to any one of claims 1 to 6, wherein an output acceleration during shaking is detected. 8. A velocity signal from a velocity input terminal is input to a drive amplifier through an integrating circuit to drive the piezoelectric actuators of the respective axes, and a movable block is provided with an acceleration sensor of the respective axes so as to generate vibration. The vibration test apparatus according to any one of claims 1 to 6, wherein the output acceleration is detected.