JPS62126876A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To eliminate external transmission of a noise and a vibration by interposing an elastic member such as rubber between a movable body of a traveling vibration wave motor and a member moving integrally with the body. CONSTITUTION:A vibration of a vibration wave motor periodically projects a movable body 17 contacted under pressure with a vibrator 15. A rubber ring 18 is interposed between the body 17 and a rotary cylinder 6 to prevent a vibration and a noise between the vibrator 15 itself and the body 17 from transmitting not only to the cylinder 6 but also to a plurality of balls 20. The ring 18 is formed of a material having excellent vibration attenuating property such as butyl rubber, or a urethane rubber.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a vibration wave motor that displaces a moving body such as a rotor using vibration waves generated by an electro-mechanical energy conversion element such as an electrostrictive element. be.

<Prior art> Conventionally, as a vibration wave motor, a driving signal is applied to an electrostrictive element to generate a traveling wave on a vibrating body to which the electrostrictive element is fixed, and the traveling wave is applied to a moving body to displace it. Various methods are known, such as applying displacement of an electrostrictive element directly to a moving body and displacing it.
As shown in Japanese Patent Application Publication No. 2003-120012, a device that uses focus adjustment by constricting a vibration wave motor is known.

However, since the vibration wave motor drives a moving body using vibration waves generated by an electrostrictive element, vibration and noise are generated from the vibration wave motor device itself. The problem with this problem is that in the vibration wave morph, the moving body that is in pressurized contact with the vibrating body is periodically pushed up by the vertical movement of the vibrating body surface or the displacement movement of the electrostrictive element itself, and this occurs at several locations, which causes noise and noise. Vibration occurs, and when it is incorporated into a lens barrel, for example, it can interfere with photography and cause camera shake.

<Object of the Invention> The present invention is intended to reduce the vibration and noise of the conventional vibration wave motor described above, and to eliminate it reliably in a simple manner when the motor is incorporated into equipment such as a lens barrel.

The present invention aims to dramatically reduce the above-mentioned vibrations and noise by attaching an elastic member made of rubber or the like to at least a part of the space between the movable body and the transmission part in a vibration wave motor. It has become possible to stabilize the operation of the vibration wave motor with an extremely simple means that is only attached to at least a portion between the movable body and the transmission member.

Ku-U example> Hereinafter, specific embodiments of the invention will be described in detail.

As mentioned above, various types of vibration wave motors are known in which a moving object is driven by vibration waves generated by an electrostrictive element. The present invention is of a type in which a moving body is moved by the traveling wave by forming a wave, and specifically, an example will be described in which it is applied to an interchangeable lens for a single-lens reflex camera incorporating a vibration wave motor.

Figure 1 shows the structure of a lens when a vibration wave motor is applied to an interchangeable lens for a single-lens reflex camera. In the cross-sectional view, 1 indicates a mount that is attached to the lens attachment part of the camera body (not shown). 2 is a fixing screw, 3 is a fixing tube that is integrally connected to the mount 1 by the fixing screw 2, and 4 is a back cover, which is elastically connected to the mount 1 by an elastic portion 4a.

Further, 5 indicates a group of contact points for exchanging signals with the camera body (not shown).

6 is a rotating cylinder having a rotating helicoidal screw rotated by a vibration wave motor to be described later; 7 is a rotating cylinder 8 located in the rotating hem 7;
The lens section shown by moves straight and the focus is adjusted. Further, the rectilinear cylinder 7 has an aperture unit 9, and the aperture unit 9 also advances linearly together with the lens portion 8.

Note that lO indicates a coil of a motor that drives the aperture blades of the aperture unit 9, but since it is not directly related to the present invention, its details will be omitted.

A disc spring indicated by 11 on the fixed cylinder 3 includes a washer indicated by 12,
In addition to the vibration absorber 13 made of felt or the like, a plurality of electrostrictive elements 14 are arranged in a phase difference manner on the side of the vibration absorber 13, or a plurality of electrostrictive elements 14 are polarized in a phase difference manner.
A pair of electrostrictive elements 14 are connected to an annular vibrating body 15 having a trapezoidal cross section.
A voltage is applied to the terminal 16 of the electrostrictive element 14 to cause the vibrating body 15 to generate a progressive vibration wave.

The movable body 17 having a flange r; Rt 7 a is connected to the rotary cylinder 6
are integrally connected by a pin shown at 19 via a rubber J1 shown at 18, and the rotating cylinder 6 is rotated integrally with the movable body 17 by progressive vibration waves generated in the vibrating body 15.

The rotating barrel 6 is provided with a V-groove 6a, and a plurality of poles 20 are held by a pole receiver 21 fitted into the fixed barrel 3 and a pole holder 22 screwed into the fixed barrel 3, and the rotating barrel is held by a plurality of poles 20. The aim is to reduce frictional resistance and make the rotation more circular.

The vibrating body 15 urged in the optical axis direction by the disc spring 11 and the movable body 17 having the flange 17a come into pressure contact, and the progressive vibration waves generated by the vibrating body 15 cause the movable body to 17 is friction driven.

FIGS. 2(a), 2(b), 2(c), and 2(d) show diagrams of the principle of the progress of vibration waves when such a polarization type electrostrictive element is used.

Suppose that the progressive bending vibration wave now advances in the direction of arrow X.

If 0 is the central plane of the vibrating body in the resting state, then in the vibrating state it is in a state shown by a chain line 26, and the stress due to bending is balanced on this central plane 26. When looking at the cross section 27 perpendicular to the center plane 26, no stress is applied at the intersection line 25 of these two planes, and it only vibrates vertically. At the same time, cross section 27
The pendulum oscillates left and right about the intersection line 25.

In the state shown in FIG. 4A, a point P on the intersection line between the cross section 27 and the moving body side surface of the vibrating body 15 is the right dead center of left-right vibration, and is only moving upward. In this pendulum vibration, when the intersection line 25 is on the positive side of the wave (above the center plane ○), stress is applied to the left (in the opposite direction to the wave's progress), and when it is on the negative side of the wave (also on the bottom side) Then stress is applied in the right direction. That is, in the same figure (a), when the intersection line 25' and the cross section 27' are the former, stress is applied to the point y, and when the intersection line 25' and the cross section 2γ are the latter, the stress V is applied to the point V. join. As the wave progresses, as shown in b), when the intersection line 25 comes to the positive side of the wave, point P moves to the left and at the same time moves upward. In (C), point P moves only to the left at the top dead center of the vertical vibration. (d
) makes a leftward movement and a downward movement. The wave further advances, moves rightward and downward, moves rightward and upward, and returns to state (a). When this series of motions is combined, the point P is interlocked with an ellipse of revolution, and the radius of rotation is a function of t/2, where t is the thickness of the vibrating body. One side view (C)
As shown in FIG. 1, on the line where point P touches the moving body 17, the movement of the point P causes the moving body 17 to be frictionally driven in the forward direction.

The vibration of the vibration wave motor is caused by periodically pushing up the moving body 17 that is in pressure contact with the vibrating body 15, and the vibration and noise generated by the vibration wave motor are integrally coupled with the moving body 17. It is transmitted to the rotating cylinder 6 and the plurality of poles 20. The plurality of poles 20 are connected to hole receivers 21. It slides between the pole holder 22 and the rotary cylinder 6, and since there are a plurality of them, the noise becomes louder.

The rubber ring 18 is interposed between the movable body 17 and the rotary tube 6, and transmits vibrations and noise between the vibrating body 15 of the vibration wave motor itself and the movable body 17 not only to the rotary tube 6 but also to the plurality of poles 20. prevent it from being transmitted.

The rubber ring 18 is preferably made of a material with excellent vibration damping properties, particularly butyl rubber, urethane rubber, etc.

Furthermore, since it is sufficient to prevent the vibration of the moving body 17 from being transmitted to the rotating cylinder 6, the same effect can be obtained even if a viscous body is used in place of the rubber ring. The bin 19 for this purpose can be omitted.

<Effects of the Invention> As explained above, by attaching a rubber mesh member between the moving body of the progressive vibration wave motor and the member that moves integrally with the moving body, the connection between the vibrating body and the moving body can be improved. It is possible to absorb the noise and vibrations generated between cameras, so that the noise and vibrations are not transmitted to the outside, and when the subject is not only the photographer, but the subject is a person, unpleasant sounds are produced, which can interfere with photography. This has the effect of preventing camera shake caused by rough vibrations when taking pictures.

[Brief explanation of drawings]

FIG. 2 is a sectional view of a lens barrel incorporating the vibration wave motor device according to the first invention, and FIG. 2 is a diagram showing the operating principle of the vibration wave motor device shown in the first figure. 6--Rotating tube 14--Electrostrictive element 15--
- Vibrating body 17 - - Moving body 18 - Rubber ring
19--pin 20-1-pole 21-
--Pole holder 22-1-Pole holder) #-X l 3a 1-=-x

Claims (1)

[Claims] A vibrating body that generates a traveling vibration wave by a drive signal applied to an electro-mechanical conversion energy element, and a movable body that is displaced by the vibration wave, and a member that moves integrally with the movable body and the movable body. A vibration wave motor characterized in that an elastic member is attached between the vibration wave motors.