JP2587931B2 - Rotary drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rotary driving body using a vibration element applied to a vibration wave motor or the like.

<Prior Art> A rotary driving body using a vibrating element such as the electrostrictive element is disclosed in JP-A-58-148682, JP-A-59-96881, and JP-A-59-96882.
No. has been proposed. In these devices, a plurality of electrostrictive elements are combined in an annular shape, each of which is polarized in the circumferential direction. By applying an alternating voltage, the phase difference is excited in the circumferential direction to generate a traveling wave on the end face. It is a thing.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 61-142976, an electrode on one side of an annular vibration element composed of an electrostrictive element or a magnetostrictive element polarized in the thickness direction is equally divided by two or more numerical values x. Then, by applying an alternating voltage with a temporal phase shift of 2x / x in the circumferential direction to each divided electrode, a circumferential traveling wave force is generated using a circumferential stretching wave called an extension mode. There is something that can be done.

As described above, various rotary driving bodies using an annular vibrating element that generates a traveling wave in the circumferential direction on an end face composed of an electrostrictive element or the like have been proposed.

<Problems to be Solved by the Invention> By the way, conventionally, in the case of using this kind of vibrating element, the vibrator is attached to a required location by performing a process of vibration leakage,
Rotational force is taken out, and the rotor is separately supported in accordance with its mounting location.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary drive body in which various constituent members are assembled and unitized to make them easy to apply to required places.

<Means for Solving the Problems> The present invention is composed of an electrostrictive element or a magnetostrictive element polarized in the thickness direction. An annular vibrating element, which generates a traveling wave force in the circumferential direction by applying an alternating voltage having a temporal phase shift of 2π / x, by utilizing a stretching wave in the circumferential direction,
It was disposed on a thick, large-mass base that could be considered as a fixed end in terms of vibration, and further, a metal cylinder was disposed on the vibrating element, and the metal cylinder was disposed vertically at the center thereof. Affixed to the base with a screw rod, pre-compressed by squeezing the vibrating element between them, placing the rotor on the cylinder,
A rotation driving body characterized in that the output shaft is supported by a bearing fixed to an upper part of a cylinder surrounding a member such as a vibration element held by a base, and protrudes outward from the cylinder.

<Operation> By driving the vibrating element, a circumferential traveling wave propagated through the cylinder acts on the rotor. This rotor is supported by a bearing held on the base side via a cylindrical body,
The rotational force is extracted from the output shaft.

<Embodiment> Figs. 1 to 3 show a first embodiment of the present invention.

Here, as shown in FIG.
An electrostrictive element 2, 2 made of a ceramic plate of T or the like is joined via four divided electrodes 3, and is polarized in the direction of the arrow in FIG. 1 so that the contact surface is positive. . The split electrode 3 has a branch terminal 4 projecting sideways from a 90-degree fan-shaped main body, whereby one side electrode of the electrostrictive elements 2 is divided into four.

The vibrating element 1 is arranged on the upper surface of a metal base 5 having a large diameter and a large wall thickness and a large mass. The vibration element 1
A metal cylinder 6 is further mounted on the top. The male screw portions 9, 9 formed at the upper and lower ends of the screw rod 8 in the vibrating element 1 and the cylinder 6 are combined with the female screw 10 formed at the center of the base 5.
By screwing into the female screw 11 formed on the inner surface of the cylinder 6, the base 5 and the cylinder 6 are connected by the screw rod 8, and the vibrating element 1 is pressed.

The vibrating element 1 is pre-compressed by this configuration. For this reason, the electrostrictive element is generally
It is weak against the force in the stretching direction, and when a large voltage is applied in the stretching direction, element cracking or peeling at the joint is likely to occur, but the compressive force is applied in the thickness direction and the large voltage is applied. This makes it possible to generate a large traveling wave.

Further, a rotor 13 is mounted on the cylinder 6. The rotor 13 includes a large-diameter flange 14 that comes into contact with the upper surface of the cylinder 6, a fitting projection 15 that fits inside the cylinder 6 at the center thereof, and an output shaft 16 that projects upward from the upper surface. The output shaft 16 is supported by a radial bearing 17 (bearing), and has an end protruding outward. The bearing
Reference numeral 17 denotes a cylindrical body which is fixed on the base 5 and surrounds the vibrating element 1 and the cylinder 6, and is provided at a center position of a cover plate 19 attached to the upper surface thereof. A spring 20 is provided between the inner ring of the bearing 17 and the large-diameter flange 14 to urge the rotor 13 toward the cylinder 6 to maintain the contact state.

The members fixed on the base 5 are housed in a substantially hermetically sealed state by the cylindrical body 18, and the rotor 13
Output shaft 16 will protrude.

In such a configuration, the total length of the structure including the base 5 and the vibrating element 1 and the cylinder 6 sequentially laminated on the upper surface thereof is equal to a half wavelength having the upper surface of the base 5 as a vibration node. However, since the base 5 is heavily heavy as described above, the vibration element 1 and the cylinder 6 resonate by / 4 wavelength, and the base 5
Is a fixed end for substantially holding the vibration element 1 and the like.

The screw rod 8 may be integrally formed on either side of the cylinder 6 or the base 5, and the cylinder 6 or the base 5 may be screwed to the protruding end.

In the present embodiment, as shown in FIGS. 2 and 3, the branch terminal 4 has two divided electrodes 3, 3 opposed in a radial direction, and each divided electrode pair has Vsin ωt and Vcos An AC having a phase of ωt is connected, and a voltage having a temporal phase shift of π / 2 in the circumferential direction is applied to each divided electrode 3. Thereby, the vibration element 1
Has its lower surface fixed to the base 5 side.
Since has a large mass, a traveling wave in the circumferential direction is generated only on its upper surface, and the traveling wave propagates on the upper surface of the cylinder 6 as a medium. This amplitude is larger than the amplitude generated on the upper surface of the vibrating element 1 because the cylinder 6 acts as a horn, and the rotor 13 is provided with a large feed amount from the large-diameter flange 14 and the output shaft 16 thereof. At high speed.

In such a configuration, the base 5 is not fixed to the other fixing portion, but is configured to be a fixed end in terms of vibration due to its weight, so that the supporting structure is simple and the manufacturing is easy. There are advantages.

In the above embodiment, the vibrating element 1 is formed by combining a plurality of electrostrictive elements in an annular shape, each of which is polarized in the circumferential direction, and the end face thereof is excited with a phase difference in the circumferential direction by applying an alternating voltage. A conventional configuration in which a traveling wave is generated on the end face may be applied, or a configuration in which the number of divided electrodes of the electrostrictive element is increased and the electrostrictive element is used in a higher mode may be used.

<Effects of the Invention> As described above, the present invention fixes the vibration element to the base, rotates the rotor via the cylinder by the vibration element, and causes the output shaft to protrude from the cylinder surrounding each vibration member. A) The components are mounted and fixed on the base to form a unit, which makes it easy to apply to required places, and furthermore, the drive unit such as the vibrating element is covered with a cylindrical body. The maintenance status is good because it is protected.

B) In general, the vibrating element is weak in the extension direction, and when a large voltage is applied, the element is liable to be broken. It is held in the thickness direction by the compressive force. Therefore, a large voltage can be applied to the vibration element, and a large driving force can be generated.

C) Unlike the configuration in which the rotor is rotated directly by the vibrating element, the rotor is rotated through the cylinder, so that the cylinder can perform a function as a horn to generate a large feed amount and precisely grind the contact surface of the cylinder. This makes it possible to generate a stable rotational force with no flutter on the output shaft. In addition, since the rotor is not directly arranged on the vibration element, the surface of the vibration element does not wear, and the life of the mode is prolonged.

D) Since the base is made heavy and the fixed end is vibrated, the supporting structure of the vibrating element is simplified and the manufacturing is facilitated.

And other excellent effects.

[Brief description of the drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a longitudinal side view, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is an exploded perspective view of the vibration element 1. is there. 1; vibrating element, 2,2; electrostrictive element, 3; split electrode, 5; base, 6;
Cylindrical, 8; screw rod, 13; rotor, 14; large diameter collar, 16; output shaft, 1
7; bearing, 18; cylindrical body

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Michiyuki Masuda 14-18, Takatsuji-cho, Mizuho-ku, Nagoya Japan Special Ceramic Industry Co., Ltd. (56) References JP-A-58-148682 (JP, A) JP-A Sho 60-109776 (JP, A) JP-A-61-30972 (JP, A)

Claims (1)

(57) [Claims] 1. An electrostrictive element or a magnetostrictive element polarized in a thickness direction, an electrode on one surface is equally divided by two or more numerical values x, and a temporal phase of 2π / x is circumferentially applied to each divided electrode. A ring-shaped vibrating element that generates circumferential traveling wave force using circumferential stretching waves by applying a displaced alternating voltage is a thick and large mass that can be regarded as a fixed end in terms of vibration. Is disposed on the base, and a metal cylinder is further disposed on the vibrating element, and the metal cylinder is fixed to the base with a screw rod disposed vertically in the center of the metal cylinder, and the vibrating element is clamped between them. The rotor is mounted on the cylinder, and its output shaft is supported by a bearing fixed to an upper part of a cylinder surrounding members such as a vibrating element held by a base. A rotary drive body characterized in that it protrudes in the direction.