JPH0332377A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To easily assemble and to reduce a weight by employing a ferroelectric liquid crystal panel, and generating a traveling elastic wave by patterning of an electrode. CONSTITUTION:An ultrasonic motor is composed of a cylindrical stator 1, and a cylindrical rotor 2 press-fitted oppositely to the inner periphery of the stator 1 into the stator 1, and driven by a drive signal supply unit 7. A flexible ferroelectric liquid crystal panel 3 formed in a cylindrical shape is provided on the inner periphery of the stator 1. The panel 3 is formed of a pair of elastic substrates 3a-3b, sealing materials 4a-4b, and a ferroelectric liquid crystal 5. Further, rectangular electrodes 3c-3d and a common electrode 3e are provided on the substrates 3a-3b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic motor using ferroelectric liquid crystal.

(Prior Art) Comprising a rotor and a stator, at least one of the two includes at least one vibrator driven by a plurality of electrostrictive cables, and a lead wire of the electrostrictive element is connected to a drive power source. , the rotor and stator press against each other at at least one point on the surface of the vibrator to transmit torque;
An ultrasonic motor that converts ultrasonic electrical energy applied to an electrostrictive element into mechanical vibration energy and converts this mechanical vibration energy into unidirectional movement of a rotor has already been disclosed in Japanese Patent Laid-Open No. 52-2.
This is disclosed in Publication No. 9192 and the like.

As one application of this principle, there is an ultrasonic motor that is composed of a stator made of a cylindrical elastic vibrator and a cylindrical rotor that is in contact with one of the inner or outer periphery of the stator.

In the ultrasonic motor configured in this way, it is necessary to bring the two opposing cylinders into pressure contact with each other. For this reason, the rotor is brought into pressure contact with the stator in the radial direction by, for example, dividing the rotor and interposing a spring between the divided parts.

(Problem to be solved) The vibration amplitude of an electrostrictive element is actually minute, about 1 to 10 μm, so if the gap between the stator and rotor is larger than this vibration amplitude, the energy conversion efficiency will be poor. Therefore, high dimensional accuracy of the rotor and stator is required. Furthermore, if the rotor is divided and a spring is interposed between the divided parts to bring the stator and rotor into pressurized contact, the torque will vary depending on the pressure applied by the springs, making it difficult to obtain uniform quality characteristics. .

Furthermore, the inner peripheral surface (or outer peripheral surface) of the cylindrical stator
Since it is necessary to attach an electrostrictive element to the cable, it is necessary to shape the electrostrictive cable into an arc shape to match the curved surface of the cable, or to apply distortion to the arc shape before attaching it.

An object of the present invention is to provide an ultrasonic motor that can be configured without using mechanical structures such as springs, is easy to manufacture, and can be made lighter and smaller.

(Means for Solving the Problems) In order to achieve the object described in (1), the ultrasonic motor of the present invention has a cylindrical stator and a cylindrical cylinder facing either the inner periphery or the outer periphery of the stator. A flexible ferroelectric liquid crystal panel consisting of a pair of wipe plates having a group of rectangular electrodes and a ferroelectric liquid crystal sealed between the substrates on this side is provided on the surface facing the rotor. . And progress based on the electrostrictive effect of ferroelectric liquid crystals? li M, a drive signal supply device for generating waves is connected to the electrode group.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the stator 1 has a cylindrical shape, and a cylindrical rotor 2 that is in contact with the inner peripheral surface of the stator 1 is press-fitted. A flexible ferroelectric liquid crystal panel 3 formed in a cylindrical shape is provided on the inner peripheral surface of the stator 1 .

As shown in FIGS. 1 and 2, the structure of the ferroelectric liquid crystal panel 3 is such that a pair of elastic substrates 3a, 3b such as polyester sheets are placed facing each other with a predetermined gap between them. The outer periphery of the liquid crystal 5 is sealed with seals 44a and 4b made of epoxy adhesive, etc., and the ferroelectric liquid crystal 5 is sealed inside. A plurality of rectangular electrode groups 3c... and 3d... are formed on the outer peripheral surface of the inner elastic double plate 3a, and electrodes are formed on the inner peripheral surface of the outer elastic substrate 3b. A common electrode 3e facing the groups 3c and 3d is formed. In the electrode groups 3c and 3d, the elongated direction of the rectangular electrodes is aligned in the axial direction, and the width direction thereof is aligned in the circumferential direction of the cylinder (see FIG. 3). Electrode n'f3c, 3
d and the common electrode 3e are connected to a connecting means 6 such as a lead wire.
A drive signal is supplied from the drive signal supply device 7 via. When a drive signal is supplied, the elastic substrate 3a bends based on the electrostrictive effect of the ferroelectric liquid crystal 5, and a unidirectional traveling elastic wave is generated along the circumferential direction of the inner peripheral surface of the stator 1. .

To explain in detail with reference to FIG. 2, one end output from the power source 7a is applied to the electrode groups 3c and 3d via a 90-degree phase shifter 7b and polarity inverters 7c and 7c as a drive signal of π/2 (
An AC voltage whose phase is advanced by rad) is applied. The other end output of the AC voltage from the power source 7a is connected to the common electrode 3e. Adjacent electrodes 3c and 3d have an applied voltage of 4
The electrodes XT3c...
and 3d... are applied with voltages having different temporal phases by π/2 (rad), so that the waves generated in both interfere with each other and are combined to form an elastic traveling wave. As a result, the substrate 3a is bent due to the electrostrictive effect of the ferroelectric liquid crystal 5, and due to the bending of the substrate 3a due to this electrostrictive effect, an elastic wave traveling along the circumferential direction is generated on the inner peripheral surface of the stator 1. It turns out. For this reason, the rotor 2 press-fitted into the stator 1 rotates in its circumferential direction.

FIG. 4 shows a second embodiment of the present invention, and in this embodiment, electrode groups 31c..., 31d... are provided on opposing surfaces of elastic substrates 31a, 3Lb, respectively. It is. In this example, the electrode group 31C... is the electrode group 3
They are formed at the same pitch and shifted by one half of the electrode width relative to 1d. And electrodes? ! T 31 c..., 3
The driving signals supplied to the electrode groups 31d... are applied with alternating current voltages having opposite phases, that is, phases different by π (rad), to the adjacent electrodes, while the electrodes of the electrode group 31d... An alternating current current whose phase is shifted by π/2 (rad) is applied to the group 31c. With such an electrode group and drive signal, the rotor can be rotationally driven in one direction as in the first embodiment.

FIG. 5 shows a third embodiment of the present invention, in which 6
Electrode group 32C...
232d... is set to -C. Although not shown, the configuration in which a common electrode is provided on the elastic substrate facing the outer periphery of the elastic substrate 32a is the same as in the first embodiment. In this example, the electrode group 32c... is the electrode H'f 32
d... are formed at the same pitch and shifted by half the electrode width. And electrode groups 32c..., 32d
The drive signals supplied to ... are the same as those in the first and second embodiments, and can drive the rotor to rotate in one direction.

In this embodiment, the rotor is disposed on the inner periphery of the stator, but a ferroelectric liquid crystal panel may be provided on the outer periphery of the stator, and a cylindrical rotor may be disposed on the outer periphery of the stator.

(Effects) As described above, according to the ultrasonic motor of the present invention, traveling elastic waves can be generated by patterning the electrodes. No additional work is required. In addition, since the ferroelectric liquid crystal panel is flexible, the rotor and stator can be connected only by press-fitting them together, eliminating the need to pressurize the rotor and stator into contact using mechanical structures such as springs as in the past. Manufacturing and assembly are easy, and weight and size reductions can be achieved.

[Brief explanation of drawings]

FIG. 1 is a partially sectional perspective view, FIG. 2 is a sectional plan view of the first embodiment, FIG. 3 is a perspective view showing the electrode arrangement of the first embodiment, and FIG. 4 is a second embodiment. 5th perspective view showing the electrode arrangement of
The figure is a perspective view showing the electrode arrangement of the third embodiment. DESCRIPTION OF SYMBOLS 1... Stator, 2... Rotor, 3... Ferroelectric liquid crystal panel, 3a, 3b, 31a, 31b, 32a3c
3d, 3e, 31c, 31d. 5... Ferroelectric liquid crystal, 7... Drive signal supply device.・Elastic substrate, 32c 32d... Electrode,

Claims (1)

[Claims] The stator includes a cylindrical stator, and a cylindrical rotor that is in contact with either the inner or outer periphery of the stator, and the stator has a rectangular rotor on the surface that faces the rotor. A flexible ferroelectric liquid crystal panel is provided, consisting of a pair of elastic substrates having electrode groups and a ferroelectric liquid crystal sealed between the two substrates. An ultrasonic motor characterized in that a drive signal supply device for generating traveling elastic waves is connected to the electrode group.