JPH06238237A - Adjustment of prestress of vibrator - Google Patents

Abstract

PURPOSE:To produce a high-precision and efficient vibrator capable of finely adjusting the prestress due to a plurality of springs within a short time while keeping a degree of parallelization. CONSTITUTION:In a vibrator using a magnetostriction rod 11 composed of a super-magnetostriction rare earth alloy, a plurality of the prestress applying springs 16 attached to a pair of flanges 14 are compressed up to the uniform stroke mechanically prescribed by press springs 19 to initially provide a degree of parallelization. By adjusting the stroke of the press springs 19 provided to the central parts of the flanges 14, all of a plurality of the springs 16 can simultaneously be adjusted in stroke and, as a result, the fine adjustment of the prestress to the magnetostriction rod 11 can be performed within a short time while the degree of parallelization is kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator (actuator) used for underwater transmission, etc. is there.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field,
For example, some documents were described in the following documents. References; Acoustical Society of Japan Proceedings (4-10) Kawamori et al.
"Respiratory vibration sound source using giant magnetostrictive material" P. 1149-
1150 FIGS. 2 (a) and 2 (b) are schematic structural views of a conventional vibrator described in the above-mentioned documents, etc., where FIG. 2 (a) is a plan view and FIG. 2 (b) is a sectional view. is there. This oscillator has a magnetostrictive rod 1 made of a giant magnetostrictive rare earth alloy. A solenoid coil 2 for driving the magnetostrictive rod is provided on the outer circumference of the magnetostrictive rod 1. Disk-shaped flanges 4 are attached to both end surfaces of the magnetostrictive rod 1 via permanent magnets 3 for applying a magnetic bias to the magnetostrictive rod 1. The flanges 4 on both sides are connected to each other by three bolts 5 which are pre-stress applying means, and the springs 6 provided inside the flanges 4 are attached to both ends of the bolts 5 so that the magnetostrictive rod 1 is supported. The prestress is applied in parallel to the axial direction. The springs 6 are provided at all six positions so that the springs 6 can be tightened at three points from both sides of the pair of flanges 4 in consideration of the distribution of force and the mechanical balance. In the vibrator with the above configuration,
When an alternating current is input to the solenoid coil 2, magnetostrictive expansion / contraction vibration is performed around the magnetic bias point defined by the permanent magnet 3. This vibration is transmitted to the pair of flanges 4 and output to the outside in the form of a sound wave (ultrasonic wave or the like).

FIG. 3 is a diagram showing changes in magnetostrictive characteristics depending on the magnitude of prestress applied to the giant magnetostrictive rare earth alloy forming the magnetostrictive rod 1 of FIG. The horizontal axis represents the total applied magnetic field MF including the magnetic bias MB, and the vertical axis represents the strain amount ST of the giant magnetostrictive rare earth alloy. Note that AF on the horizontal axis in FIG. 3 is an alternating magnetic field, and L is the natural length of the magnetostrictive material at the intersection of the horizontal axis and the vertical axis. Also, PS1 is the curve when prestress is optimal,
PS2 is a curve when the prestress is larger than the optimum value,
PS3 is a curve when the prestress is smaller than the optimum value. As shown in FIG. 3, the magnetic bias MB is determined by the designed permanent magnet 3 and cannot be changed. However, the giant magnetostrictive rare earth alloy forming the magnetostrictive rod 1 has a larger variation in magnetostrictive characteristics for each sample during manufacturing than the permanent magnet 3. Therefore, in the conventional prestress adjusting method for the vibrator, the magnetic bias MB point is located at the center of the linear expansion / contraction range of the magnetostrictive rod 1, so that the springs 6 at the six locations provided on the pair of flanges 4 are provided for each vibrator. The pre-stress is finely adjusted by individually adjusting with the same stroke, and the magnetostrictive characteristic as shown in FIG. 3 is checked each time. Then, when it is determined that the prestress optimum curve PS1 of FIG. 3 is obtained, the production of the vibrator is finished.

[0004]

However, in the conventional prestress adjusting method, the prestress of the vibrator must be finely adjusted by adjusting the six springs 6 individually with the same stroke. It is a three-point tightening adjustment while measuring the stroke. Therefore, it is difficult to perform fine adjustment while maintaining the parallelism of the pair of flanges 4, and the adjustment itself requires a long time, which causes a problem that the manufacturing efficiency of the vibrator is poor, which is difficult to solve. Met. The present invention solves the problems of the above-mentioned conventional technology in terms of parallelism and adjustment time in prestress fine adjustment, and makes fine adjustment of all strokes of the prestressing spring by adjusting the parallelism of the entire system. It is intended to provide a method for adjusting a prestress of a vibrator, which can be simultaneously performed while keeping the same.

[0005]

In order to solve the above-mentioned problems, the present invention is formed by using a giant magnetostrictive rare earth alloy,
A magnetostrictive rod that expands and contracts in the axial direction according to the magnitude of an alternating magnetic field that acts from the outside, a pair of flanges that are attached to both end faces of the magnetostrictive rod and vibrate due to the strain of the magnetostrictive rod, and a plurality of prestressing springs. In a prestress adjusting method for a vibrator, which comprises a pair of flanges and a prestress applying means for applying a prestress to the magnetostrictive rod in the axial direction thereof, the following means are taken. That is, in the present invention, a push screw for adjusting the stroke of the plurality of springs is provided at the flange portion at the center of the plurality of springs. Then, the strokes of the plurality of springs are tightened to a mechanically uniform size in advance and initialized, and then the plurality of springs are simultaneously changed by the same stroke by the push screw to finely adjust the prestress.

[0006]

According to the present invention, since the prestress adjusting method for the vibrator is configured as described above, in order to give the optimum prestress to the magnetostrictive rod made of the giant magnetostrictive rare earth alloy,
When the push screw provided on the flange is screwed in to the specified stroke and the plurality of prestressing springs on the flange side are tightened to the strokes of mechanically specified uniform dimensions in the initial setting, a pair of flanges are initially set. Parallelism is maintained. After the parallelism is obtained in this way, the stroke of the push screw provided on the flange is adjusted, and all springs are simultaneously changed by the same stroke to finely adjust the prestress for the magnetostrictive rod. As a result, all the springs are adjusted at the same stroke at the same time, and as a result, the prestress is finely adjusted while maintaining the parallelism, and the adjustment work can be performed in a short time. Therefore, the above problem can be solved.

[0007]

1 (a) and 1 (b) are schematic structural views of a vibrator showing an embodiment of the present invention. FIG. 1 (a) is a plan view,
And FIG. 2B is a sectional view. This oscillator has a magnetostrictive rod 11 made of a giant magnetostrictive rare earth alloy such as terbium / dysprosium / iron (TbDyFe). The magnetostrictive rod 11 is used from one to a plurality depending on the purpose of use, but FIG. 1 shows the case where one rod is used. A solenoid coil 12 for applying an alternating magnetic field is provided on the outer circumference of the magnetostrictive rod 11. A pair of disk-shaped flanges 14 made of brass or the like are attached to both end surfaces of the magnetostrictive rod 11 via permanent magnets 13 for applying a magnetic bias to the magnetostrictive rod 11.
Permanent magnets 13 attached to both end surfaces of the magnetostrictive rod 11.
Are slidably inserted into magnet mounting holes 14a formed inside the pair of flanges 14, respectively. The pair of flanges 14 on both sides are connected to each other by a plurality of (for example, three) bolts 15 which are pre-stress applying means. That is, each of the pair of flanges 14 has three spring mounting holes 14b into which both ends of the three bolts 15 are inserted, and a washer receiving portion 14c is formed in each spring mounting hole 14b. A coil-shaped spring 16 for applying prestress is inserted in each spring mounting hole 14b, and both ends of each bolt 15 are inserted in each spring 16.

A nut 18 is attached to both ends of each bolt 15 via a washer 17, and a spring 16 inserted between the washer 17 and one end of a spring attaching hole 14b causes a magnetostrictive rod 11 to pass through a flange 14. On the other hand, the prestress is applied parallel to the axial direction. The washer 1 inserted in each spring mounting hole 14b
Numeral 7 is adapted to be locked by a stepped washer receiving portion 14c formed in the spring mounting hole 14b. Also,
A magnet mounting hole 1 is provided at each central portion of the pair of flanges 14.
Mounting holes 14d connected to 4a are formed respectively. Push screws 19 for simultaneously adjusting the strokes of the springs 16 at three locations are screwed into the respective screw mounting holes 14d. In the vibrator configured as described above, when an alternating current is input to the solenoid coil 12, the magnetostrictive rod 11 makes a magnetostrictive expansion / contraction motion around the magnetic bias points defined by the permanent magnets 13 on both sides. This vibration is transmitted to the pair of flanges 14 via the permanent magnets 13 on both sides and the push screw 19, and is output to the outside in the form of a sound wave (ultrasonic wave or the like).

4 (a), (b) and FIG. 5 (a),
(B) is a figure which shows the manufacturing process of the vibrator shown in FIG. S1 and S2 in FIGS. 5A and 5B are strokes of the spring 16 at six locations. With reference to these drawings, a manufacturing process of the vibrator of FIG. 1 will be described, and a prestress adjustment method of the present embodiment will be described. When manufacturing the vibrator of FIG. 1, first, as shown in FIG. 4A, permanent magnets 13 are fixed to both ends of a magnetostrictive rod 11 made of a giant magnetostrictive rare earth alloy inserted in a solenoid coil 12. .
Further, the respective permanent magnets 13 are inserted into the magnet mounting holes 14a in the pair of flanges 14, and the respective flanges 14 are covered with the respective permanent magnets 13. Then, as shown in FIG. 4B, the push screws 19 screwed into the screw mounting holes 14d in the respective flanges 14 are screwed in to the specified strokes.

Next, as shown in FIG. 5 (a), nuts 18 screwed on both ends of three bolts 15 via washers 17 are formed in the spring mounting holes 14b at six locations, and the washer receiving portions are formed. Until the washer 17 comes into contact with 14c, the six springs 16 passed through the bolts 15 are tightened.
In addition, the springs 16 at the six positions are initially adjusted to the stroke S1 with a small error according to the mechanism accuracy. After the initial adjustment of the springs 16 at the six locations, as shown in FIG. 5B, the push screws 19 screwed onto the pair of flanges 14 are attached to the springs 16.
Stroke is the optimum prestress in design (PS in Fig. 3
It is pulled out at the stroke S2 corresponding to 1), and the magnetostrictive characteristic of the magnetostrictive rod 11 is checked here. If the magnetic bias MB shown in FIG. 3 is not in the optimum position, the push screw 1
The fine adjustment of only the stroke for 9 is repeated. By the vertical movement of the push screw 19, all the springs 16 are adjusted at the same stroke at the same time. As described above, in the prestress adjusting method of the present embodiment, all of the six springs 16 passed through the both ends of the three bolts 15 are tightened until the washer 17 contacts the washer receiving portion 14c, and the initial setting is performed. By vertically moving the push screw 19 screwed to each flange 14, all strokes of the springs 16 at six locations are adjusted simultaneously and equally. Therefore, the fine adjustment of the prestress to the magnetostrictive rod 11 can be performed in a short time while maintaining the parallelism only by adjusting the stroke of the push screw 19. Therefore, the vibrator using the giant magnetostrictive rare earth alloy can be highly accurately and It is possible to manufacture efficiently.

The present invention is not limited to the above embodiment,
Various changes are possible. (1) In the above embodiment, the bolt 15 and the spring 16 are used to configure the prestress applying means, but springs having other shapes and structures may be used to configure the prestress applying means other than those shown. . (2) In FIG. 1, the washer receiving portion 14c and the washer 17 are provided.
Although all strokes of the six springs 16 are initialized by using and, it may be initialized by using other engaging means. Further, four or more bolts 15 and eight or more springs 16 inserted at both ends thereof may be provided at eight or more positions depending on the purpose of use. Similarly, you may make it the structure which provides one magnetostrictive rod 11 in multiple numbers. (3) Although the permanent magnet 13 is slid by the push screw 19 in FIG. 1, a magnetic coupler is provided between the permanent magnet 13 and the magnetostrictive rod 11, or the vertical movement of the push screw 19 is directly performed. It may be added to both end faces of the magnetostrictive rod 11. The prestress adjusting method of the present invention is also applied to a structure in which a pair of flanges 14 are slidably attached to a shaft and bending stress and shearing force acting as external forces are absorbed by the shaft to prevent bending of the magnetostrictive rod 11 and the like. Applicable.

[0012]

As described above in detail, according to the present invention, a plurality of springs provided on a pair of flanges are mechanically tightened in advance by push screws to a uniform size, and then the initial setting is performed. Since all the springs are simultaneously changed by the same stroke by the screws to finely adjust the prestress, the fine adjustment of the prestress can be performed in a short time while maintaining the parallelism only by adjusting the stroke of the push screw. Therefore, the vibrator using the giant magnetostrictive rare earth alloy can be manufactured with high accuracy and efficiency.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of a vibrator showing an embodiment of the present invention.

FIG. 2 is a schematic structural diagram showing a conventional vibrator.

FIG. 3 is a diagram showing changes in magnetostrictive characteristics of a giant magnetostrictive rare earth alloy forming the magnetostrictive rods of FIGS. 1 and 2.

FIG. 4 is a diagram showing a manufacturing process of the vibrator shown in FIG. 1.

5A to 5D are views showing a manufacturing process of the vibrator shown in FIG.

[Explanation of symbols]

 11 Magnetostrictive Rod 12 Solenoid Coil 13 Permanent Magnet 14 Flange 14a Magnet Mounting Hole 14b Spring Mounting Hole 14c Washer Holder 14d Screw Mounting Hole 15 Bolt 16 Spring 17 Washer 18 Nut 19 Push Screw

Claims (1)

[Claims] 1. A giant magnetostrictive material formed of a rare earth alloy,
A magnetostrictive rod that expands and contracts in the axial direction according to the magnitude of an alternating magnetic field acting from the outside, a pair of flanges attached to both end faces of the magnetostrictive rod and vibrating by the strain of the magnetostrictive rod, and a plurality of prestressing springs A prestress adjusting means for pressing a pair of flanges to apply a prestress to the magnetostrictive rod in the axial direction of the magnetostrictive rod, and a prestressing screw for adjusting strokes of the plurality of springs. Is provided at the flange portion at the center of the plurality of springs, and the strokes of the plurality of springs are tightened to a mechanically uniform size in advance and initialized, and then the plurality of springs are simultaneously changed by the same stroke by the push screw. A prestress adjustment method for a resonator, which comprises finely adjusting the prestress.