JPH0567194U - Piezoelectric motor - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a shape in which a piezoelectric motor directly contacts the surface of a rotating member to rotate without interposing an elastic member or a rod. [Structure] The tip of the unimorph type diaphragm 3 or the bimorph type diaphragm is brought into direct contact with the surface of the rotating member 4 to cause rotation, and the frequency can be switched to enable forward and reverse rotation. [Effect] It is possible to obtain an extremely small piezoelectric motor with a small number of members and assembling steps, and to provide a low-priced product with excellent efficiency and performance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor using a piezoelectric body.

[0002]

[Prior Art]

 Conventionally, a piezoelectric motor is characterized in that it is rotated by acting on a rotating member via a rod-shaped or elastic member attached to the piezoelectric diaphragm in the vicinity of a node of the piezoelectric diaphragm. It is proposed in Japanese Patent Laid-Open No. 60-62877.

[0003]

[Problems to be solved by the device]

 However, the above method has the following problems. The rod-shaped or elastic member attached to the piezoelectric diaphragm causes the rotating member to rotate, which is an obstacle to the transition of the piezoelectric motor body to a minimal shape. In order to improve the performance, it is necessary to arrange members that further increase the vibrations excited by the vibrator, and the shape of the main body has expanded, and the increase in the members has also made it impossible to reduce the assembly cost. The present invention provides an inexpensive piezoelectric motor with improved performance by reducing the number of members and the number of assembly steps.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, one or two unimorph or bimorph type diaphragms are directly contacted with a rotating member and static pressure or dynamic pressure is applied to further rotate them in a reciprocal manner. ..

[0005]

[Action]

 An elastic member, with one end fixed and the other end free, is attached to the piezoelectric member by directly contacting the free end with the rotating member to generate an AC voltage or pulsed ultrasonic electrical signal. Thus, the elastic member having the piezoelectric ceramic material attached thereto is caused to act to generate an elliptical motion at the above-mentioned tip portion, thereby freely changing the rotation of the rotating member.

[0006]

【Example】

 Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of the piezoelectric motor according to the present invention. The piezoceramic material 2 is fixed via an elastic plate made of a phosphor bronze plate or the like to form a unimorph type vibration plate 3. One end of the unimorph type diaphragm 3 is fixed to the substrate or case of 5 and the other end is a free end and is in contact with the rotatable rotating member 4.

When a pulsed ultrasonic electric signal to AC voltage as shown in FIGS. 2 and 3 is applied to the unimorph type vibration plate 3, an elastic plate made of a piezoelectric ceramic material 2 and a phosphor bronze plate as shown in FIG. The tip portion 1a of 1 repeats the standing wave of the elliptic motion by a subtle forward component force (a, b) to rotate the rotating member 4 which is in direct contact. The tip portion 1a generates a component force (a, b) in the circumferential direction due to the elastic deformation of the elastic plate 1 in the thickness direction due to the application of a pulsed ultrasonic signal, and the so-called tip portion 1a is like a forward elliptical motion. To obtain the rotating force. It should be noted that it is possible to obtain an efficient rotational force by providing an appropriate taper angle to the rotating member 4 in the shape of the tip portion 1a.

In another embodiment shown in FIG. 5, a piezoelectric ceramic material 2 is fixed by interposing an elastic plate 1 such as a phosphor bronze plate to form a bimorph type vibration plate 7. When the pulsed ultrasonic signal or AC voltage is applied to such a bimorph type diaphragm 7, the tip portion 1a of the elastic plate 1 repeats a standing wave of a subtle forward elliptic motion and the rotating member 4 rotates. Get rolling force. When the bimorph type diaphragm 7 is used, the degree of displacement of vibration becomes large, so that an effect of increasing the rotational torque is produced.

As the next embodiment, as shown in FIG. 6, an embodiment using two unimorph type diaphragms 3 and 6 will be described. Similar to the above, one end is fixed to the substrate 5 or the case, and the free end portion 1a of one end contacts the rotatable rotating member 4 so that both unimorph type diaphragms 3 and 6 are supplied with different AC voltage or pulsed shape. When an ultrasonic signal is applied, the unimorph type diaphragm 3 is flexibly deformed by the thickness to generate a component force in the circumferential direction, and the tip portion 1a repeats the standing wave of the forward elliptic motion, and the rotating member 4 is rotated. Give a rotational movement to. Further, since one of the unimorph type diaphragms 6 has a frequency signal different from that of the unimorph type diaphragm 3, the tip portion 1a of the diaphragm 6 only gives a subtle amplitude motion to the rotating member 4. Therefore, it does not hinder the rotational movement. Further, it is possible to change to the backward elliptic motion component (c, d) by changing the frequency signal. Therefore, the rotation torque is also improved. Next, the effect that the direction of rotation is reversed by switching the frequency signals of the unimorph type diaphragms 3 and 6 described above will be explained. The tip portion 1a of the unimorph type diaphragm 6 in FIG. When the rotary motion is applied to the rotary member 4 by a wave, it is similar to the rotary motion given by the unimorph diaphragm 3, but the rotary member 4 is reversely rotated due to the positional relationship. Therefore, the unimorph type diaphragm 3 is changed to a form that gives a subtle amplitude motion to the rotating member 4.

FIG. 7 shows an embodiment in which two bimorph type diaphragms are used. A mechanism that gives forward and reverse rotations like the unimorph type, and the effect of the bimorph type is that the displacement amount of the amplitude is as described above. It is large and the rotation torque is improved. By the way, to show the effect of the present invention, a motor with a space of 4 to 5 mm square can output a torque of about 5 × 10 ⁻⁴ N · m with a rotation torque of 0.3 W, so that a toy, miniature set, or It has a remarkable effect on applications such as household products and housing equipment.

[0011]

[Effect of the device]

 The piezoelectric motor according to the present invention can be obtained by a unimorph having a piezoelectric element and an elastic member, or a bimorph type vibration plate and a very limited member such as a rotating member, and a simple switch for either forward or reverse rotation. In addition to being obtained by operation, no commutator is required and noise due to arcs etc. does not occur, and high and low rotations can be freely obtained by changing the frequency. Furthermore, it is possible to obtain a motor that is light in weight and weighs less than 5 g, and a low-priced piezoelectric motor can be obtained due to the small number of assembly steps.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a motor using a unimorph type diaphragm showing an embodiment according to the present invention.

FIG. 2 is a waveform diagram of a pulsed ultrasonic signal.

FIG. 3 is a waveform diagram of an AC voltage.

FIG. 4 is an enlarged configuration diagram of a tip portion of a unimorph type diaphragm according to an embodiment of the present invention.

FIG. 5 is a configuration diagram of a bimorph diaphragm according to an embodiment of the present invention.

FIG. 6 is a configuration diagram of a unimorph type diaphragm according to another embodiment of the present invention.

FIG. 7 is a configuration diagram of a bimorph type diaphragm according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Elastic member 1a Tip part 2 Piezoelectric ceramic material 3,6 Unimorph type diaphragm 4 Rotating member 5 Substrate or case 7,8 Bimorph type diaphragm a, b, c, d Component force

Claims (2)

[Scope of utility model registration request] 1. A unimorph or bimorph type vibration plate having an elastic member attached to a piezoelectric ceramic material is brought into direct contact with a rotatable rotary member, and static pressure or dynamic pressure is applied to the vibration plate. A piezoelectric motor characterized by rotating a rotating member. 2. A unimorph or bimorph type vibration plate is provided at two positions of a rotatable rotary member, and the two vibration plates are provided with an alternating voltage or a pulsed ultrasonic electric signal having different frequencies. The piezoelectric motor according to claim 1, wherein the rotating member is rotated in a reciprocal manner.