JPH03212177A - Ultrasonic transducer and method for manufacturing the ultrasonic transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic transducer and a method for manufacturing the same, and more particularly relates to joining an elastic body and an excitation body in the ultrasonic transducer. It is.

[Prior Art] Conventionally, in ultrasonic vibrators that need to produce a strong output, the following techniques have been used to join an elastic body and an excitation body. For example, in a Langevin vibrator, when an electromechanical transducer, which is an excitation body, is attached to an elastic body, mechanical connection is performed by tightening bolts. Furthermore, devices that are bonded using organic or inorganic adhesives are also known.

However, these bonding methods have the disadvantage that the bonding strength is low. Therefore, joining methods such as brazing and solid phase joining methods are being considered.

[Problem to be solved by the invention] However, these methods have the problem that it is necessary to heat to a very high temperature and apply high pressure during bonding, and furthermore, There was a problem in that large-sized equipment was required.

The present invention has been made to solve the above-mentioned problems, and makes it possible to easily improve the bonding strength between the elastic body and the excitation body of an ultrasonic vibrator to the breaking strength of the material itself. The purpose is to provide a method for easily obtaining strong bonding force. Another object of the present invention is to provide an ultrasonic transducer that can be manufactured by a simpler method.

[Means for Solving the Problems] In order to achieve this object, the ultrasonic transducer of the present invention includes an elastic body and an excitation body that excites ultrasonic vibrations in the elastic body. The elastic body is made of a shape memory alloy, and the excitation body is coupled to a predetermined position of the elastic body.

Further, the ultrasonic vibrator of the present invention has an elastic body made of a shape memory alloy that memorizes a specific shape and has a connectable part that can be connected to an excitation body, and the connectable part is deformed to facilitate coupling with the excitation body. After that, the excitation body is coupled to the connectable portion of the elastic body, and then the elastic body is heated or cooled to a phase transition temperature.

[Operation] In the ultrasonic vibrator of the present invention having the above-described configuration, the elastic body and the excitation body are coupled by mechanical coupling force such as unevenness. Therefore, the bonding force between the two is strong.

In addition, in the method for manufacturing an ultrasonic transducer of the present invention, a shape memory alloy serving as an elastic body is memorized in advance to have a specific shape that firmly connects with the excitation body, and then the shape is deformed to facilitate the connection with the excitation body. . After that, the excitation body and the shape memory alloy are combined. The shape memory alloy is then brought to a phase transition temperature. Then, the shape memory alloy returns to its original shape and is firmly bonded.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are perspective views showing the ultrasonic transducer of this embodiment. First, the configuration of the ultrasonic transducer of this embodiment will be explained with reference to FIGS. 1(a) and 1(b). The ultrasonic transducer 11 of this embodiment has a rectangular flat plate shape, and an elastic body 21 made of a titanium-nickel (Ti-Ni) based shape memory alloy.
have.

The shape and dimensions of the elastic body 21 are adjusted so that the elastic body 21 bends and vibrates in a free secondary mode at both ends in the thickness direction at a predetermined frequency f, and longitudinally vibrates in a primary mode at both ends in the length direction at the same frequency f. has been done. Generally, the resonant frequency of longitudinal vibration propagating in an elastic body depends on the length of the elastic body, and the resonant frequency of bending vibration in the thickness direction depends on the length and thickness of the elastic body. Therefore, designing the elastic body 21 as described above is easy and well known, so the details thereof will be omitted.

As shown in FIG. 1(a), the elastic body 21 is provided with a recessed portion 24 on a predetermined side surface, and further provided with a recessed portion 25 on a side surface perpendicular to the predetermined side surface. A first piezoelectric body 22 for exciting bending vibration in the elastic body 21 and a second piezoelectric body 23 for exciting longitudinal vibration in the elastic body 21 are fitted into these depressions 24 and 25. . This fitting method will be explained in detail. The shape of the recessed portion 24 is memorized so that the length al and width shown in the figure have the following relationship with the length a1゛ and width b1° shown in the figure of the first piezoelectric body 22. ing.

a.
The shape is memorized so that it has the following relationship.

a2<82', b2<b2° Next, such an elastic body is deformed so that the following relationship is established.

al>as',b,>b,"a2>a2',t)2>I)2'After deforming in this way, the first piezoelectric body 2 is placed in the depressed portion 24.
2, and the second piezoelectric body 23 is inserted into the recessed portion 25.
Insert. Thereafter, the elastic body is heated to a phase transition temperature.

Then, the elastic body returns to the shape before deformation, and the first piezoelectric body 22 and the second piezoelectric body 23 are firmly fitted into the recessed portions 24 and 25 due to the above-mentioned relationship.

The operation of the ultrasonic transducer 11 configured as above will be explained below.

First, when an AC voltage of frequency f is applied to the first piezoelectric body 22 to cause it to vibrate, the elastic body 21 vibrates in the secondary mode of bending vibration, and an AC voltage of frequency f is applied to the second piezoelectric body 23. When applied and vibrated, the elastic body 21 vibrates in the first-order longitudinal vibration mode. At this time, by adjusting the amplitude and phase of the voltages applied to the first piezoelectric body 22 and the second piezoelectric body 23, it is possible to generate approximately elliptical motion vibration of an arbitrary shape at a predetermined position of the elastic body 21. It becomes possible.

Next, the configuration of a linear ultrasonic motor using the above-mentioned ultrasonic transducer 11 will be explained based on FIG. 2. In this figure, each member labeled with the same reference numeral as in FIGS. 1(a) and 1(b) is the same as each member described in detail above.

In the linear ultrasonic motor 31, the ultrasonic vibrator 11 is fixed to a yoke 32, and a drive portion 33 is formed at one end of the elastic body 21 of the ultrasonic vibrator 11. A movable element 34 is press-fitted to the drive section 33 by a rubber roller 35, and the movable element 34 is supported by a linear bearing 36 fixed to the yoke 32.

In the linear ultrasonic motor 31 configured as described above, when an AC voltage of a predetermined frequency is applied to the ultrasonic vibrator 11, the movable element 34 receives a driving force due to the substantially elliptical vibration of the elastic body. , moves in the direction of arrow A in the figure. This driving force is generated by the frictional force between the elastic body and the movable element.

In this example, a titanium-nickel (Ti-Ni) based alloy was used as an example of a shape memory alloy forming an elastic body, but as long as it has a shape memory effect, for example, copper-zinc-aluminum ( Cu-Zn-AI) based alloys as well as copper-aluminum-nickel (Cu-A I
-Ni) alloys may be used.

Further, in the above embodiment, the first-order mode of longitudinal vibration and the second-order mode of bending vibration were explained as examples, but if the resonance frequencies of longitudinal vibration and bending vibration are approximately the same, it is possible to manufacture a device using a higher-order mode. It is also possible.

Alternatively, the phase transition temperature may be set lower than room temperature, and the bonding may be performed by cooling.

Further, although the above embodiment uses a piezoelectric body as the excitation body, the present invention is not limited to this, and other elements capable of converting electrical energy into mechanical energy, such as an electrostrictive element or a magnetostrictive element, may also be used. .

Various other modifications are possible without departing from the spirit of the invention.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the excitation body of the ultrasonic transducer can be easily coupled to the elastic body, and the bonding strength between the elastic body and the excitation body can be improved. It becomes easier. Therefore, the output of the ultrasonic transducer can be greatly improved. Additionally, since no adhesive is used, there is little chance of peeling off over time. Furthermore, even if an adhesive is used, this effect will not change because the main bonding force is achieved by the mechanical bonding force between the two. Furthermore, when the ultrasonic vibrator is used in an ultrasonic motor, it becomes easy to significantly improve the output thereof.

Furthermore, unlike brazing properties, there is no need for high-temperature heating, and therefore there is no need for large equipment, which is an excellent effect.

[Brief explanation of drawings]

1 to 2 show embodiments embodying the present invention, and FIG. 1 shows the ultrasonic transducer of this embodiment before and after coupling the piezoelectric material to the elastic body. FIG. 2 is a perspective view showing the state, and FIG. 2 is a diagram illustrating an outline of a linear ultrasonic motor to which the ultrasonic vibrator is applied. In the figure, 21 is an elastic body, and 22 is a first excitation body corresponding to the first excitation body.
A piezoelectric body 23 is a second piezoelectric body 34 corresponding to the second exciting body
is a mover.

Claims (1)

[Claims] 1. Consisting of an elastic body made of a shape memory alloy material and an excitation body that excites ultrasonic vibrations in the elastic body, the excitation body being integrally coupled to a predetermined position of the elastic body. An ultrasonic transducer characterized by: 2. After deforming the connectable part of an elastic body made of a shape memory alloy that memorizes a specific shape and having a connectable part that can be connected to the excitation body to make it easier to connect to the excitation body, the elastic body can be connected to the excitation body. 1. A method of manufacturing an ultrasonic transducer, comprising: coupling an exciting body to the elastic body; and then heating or cooling the elastic body to a phase transition temperature.