JP3160018B2 - Vibration wave drive with built-in differential mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention includes a driving force of the electric motor, a built-in external driving force and selective or differential mechanism enter synthesizing outputs simultaneously to the motor, the rod-shaped vibration wave motor, especially a motor , Vibration wave drive device with built-in differential mechanism
It is related to the location .

[0002]

2. Description of the Related Art In recent years, as an application of a vibration wave motor, it has been used as a drive source for auto-focusing in an interchangeable lens of a camera, and requires a special switching operation between an electric auto-focusing operation and a manual focusing operation. The present applicant has proposed a lens barrel that can be performed without the need for this. This vibration wave motor is formed in a hollow annular shape, and as a switching mechanism between auto focus and manual focus, for example, a ball race is used. A dynamic mechanism has been proposed. And the differential mechanism also vibrates
A vibration-wave drive device with a built-in differential mechanism that is formed in a hollow ring shape to surround the optical lens like a wave motor and is integrated with the lens barrel integrally with the vibration-wave motor
Have been.

[0003]

However, such a vibration wave motor with a built-in differential mechanism is optimal for a product form unique to a lens barrel in which a hollow annular shape surrounds an optical lens. However, for a wide range of product specifications and applications, the maximum outer diameter, lens arrangement, and the like are easily restricted by the motor section even if the lens barrel is limited, and the versatility is poor.
In addition, it can be said that there is no particular necessity for the application to products other than the lens barrel, for example, audio equipment and the like in terms of space and layout because of the hollow annular shape.

Further, a hollow annular vibration wave motor is expensive and, as is well known, a piezoelectric element for generating vibration is bonded to a ring-shaped vibration elastic body with an adhesive.
A complicated and time-consuming process such as a polarization process is required.

[0005] Therefore, as with the vibration wave motor of a hollow annular shape, but utilizes a vibration wave vibration, a rod-shaped vibration wave motor that allows also miniaturization of approximately easy to manufacture human pinky < It is demanded that a differential mechanism be integrally assembled with the motor, for example, to be able to freely switch between motor drive and manual drive, to output a combined force thereof, and to be adaptable to space saving.

[0006]

Means for achieving the object of the present invention is to arrange an electro-mechanical energy conversion element between elastic vibrators and to place the electro- mechanical energy conversion element in front.
The elastic vibrator is sandwiched by a connecting shaft member , and an alternating electric field is applied to the electro-mechanical energy conversion element to excite a vibration wave in the elastic vibrator to move the rotating member forward.
Oscillating wave drive that rotates around the axis of the connecting shaft member
A ball race provided on the rotating member
Receiving the rotational force of the plurality of balls arranged in
The revolving force of the plurality of balls revolving pre Symbol ball upper race Te, rotational force about the axis of the connecting shaft member
A differential output member to obtain, the said ball differential output member
And the connecting shaft member is opposed to the ball race with the
Can rotate about the axis of
An external input member, connected to the connection shaft member,
The input member and the plurality of balls are applied in the direction of the rotating member.
Pressurizing means for pressing, the rotational force of the rotating member and the
The rotational force of the external input member and the differential output member are individually obtained.
Lying in the differential mechanism built type vibration wave driving apparatus according to claim that.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings.

FIG. 1 shows a differential machine using a rod-shaped vibration wave motor .
It is sectional drawing which shows one Example of a built-in type vibration wave drive device .

1 is a connecting shaft, 2 is a spacer, 3 is a piezoelectric element superimposed in the axial direction, 4 is an electrode used for wiring for applying a voltage to the piezoelectric element, 5 is a stator, 6 is a rotor, and 7 is a retainer. The ball 8 is loosely held. 9 is a pressure rotating member,
Reference numeral 10 denotes an elastic pressing member, 11 denotes a pressure holding unit, and 12 denotes a friction washer. The above members are stacked on the axis center from the left side in the figure.

The spacer 2 abuts against the stepped portion 1-1 which is a retaining means of the shaft 1, is fitted to the shaft from the left side in the figure, and the piezoelectric elements 3 and the electrodes 4 are alternately stacked. The spacer 2, the piezoelectric element 3, and the electrode 4 are crimped and fixed to the shaft by tightening a screw portion 5-1 having an inner diameter of the stator 5 to the first screw portion 1-2 of the shaft 1.

In this embodiment, the rotor 6 is divided into two parts so that the material and the surface treatment can be selected separately.
It comprises a contact side having a flange portion 6-1 in circumferential contact with the friction drive surface 5-2 of the stator 5, and a ball race portion 6-2 in contact with the ball 8. The ball race portion 6-2 has a V-shaped peripheral groove (hereinafter, referred to as a V groove) and regulates the revolving radius of the ball. At least three or more balls (here, steel balls) having the same diameter are arranged on the V-groove. Each ball is a retainer 7
Is loosely held in a hole 7-1 at least larger than the diameter of the ball, which is arranged at substantially the same radius as the V groove on the circumference of the. The retainer 7 has a bearing portion 7-fitted with the shaft 1.
2 and is free to rotate with respect to the shaft 1. The hole 7-1 holding the ball comes into contact with the ball only by the revolution of the ball in the circumferential direction, rolls on the V-groove of the ball, and comes into sliding contact with the rotation caused by the revolution.

The pressure rotating member 9 is similar to the retainer 7 in that the shaft 1
And a V-groove 9-1 similar to the V-groove on the circumferential surface on the right side in FIG.
2 together with the ball in the thrust direction to regulate the revolving radius of the ball. The left circumferential surface of the pressure rotating member 9 in the drawing is in contact with the friction washer 12 at the circumferential surface.

The friction washer 12 is arranged so as to be substantially fitted to the shaft 1. However, in order to guarantee non-rotation with respect to the shaft portion, a not-shown D-cut or a fitted form in which rotation is stopped such as two-way cutting is employed. May be used.

From the left side of the friction washer 12, with the elastic pressing member 10 substantially fitted to the small diameter portion 11-1 of the pressing and holding member 11, the screw portion 11-2 of the pressing and holding member 11 is set.
Is connected to the second screw portion 1-3 of the shaft 1, and the pressure holding member 11 is tightened up to the step 1-4 of the screw of the shaft 1 so that the elastic pressing member 10 is connected to the friction washer 1.
2 to generate pressure and complete the assembly.

The elastic pressing member 10 is desirably a constant load type spring, in order to eliminate the variation due to the difference in the pressure and the pressure and fluctuation with time. However, rubber elastic members, coil springs, and wave washers are preferable. You may.

If the applied pressure is not stably within the desired range with the amount of charge of the elastic pressing member 10 determined from the mechanical abutment dimension, the screw connection portions 1-3 and 11-2 are individually tightened and tightened. It is easy to move the position of the steps 1-4 out of the necessary adjustment range so as to perform the adjustment.

Here, the pressing force is applied to the spacer 2, the piezoelectric element 3, the electrode 4, the stator 5, the rotor 6, the ball 8, the pressure rotating member 9, and the friction washer 12 having the shaft retaining portion 1-1 as an end. It is determined by the thrust space for the elastic pressing member, which is the difference between the stacked thrust length and the thrust length to the pressing end surface 11-3 of the pressing holding member 11. In addition, the retainer 7 does not receive the pressing force.

The operation as a vibration wave motor is classified as a so-called traveling wave type vibration wave motor and is well known, so that the description of the differential mechanism will be described below.

<A: At the time of input from a motor> When an AC current is applied to the electrode 4 from a drive circuit (not shown), the piezoelectric element 3 expands and contracts, generating a traveling wave on the stator 5 and the rotor 6 which presses and abuts in a predetermined direction. When rotated, friction washer 1
The non-rotating pressure rotating member 9 is held by the holding force set in Step 2.
The ball 8 revolves while rotating in the V groove by the relative rotation with
In this embodiment, the retainer 7 rotates at half the speed of the rotor in order to press the hole side surface of the retainer hole 7-1, and is not shown by a gear portion 7-2 provided on the outer periphery of the retainer 7. And transmits the driving force to the driven member.

<B: At the time of input from the pressure input means> The relative rotation of the non-rotating rotor 6 due to the pressure frictional force and the pressure rotating member 9 against the friction by the friction washer 12 is performed in the same manner as in the above A. Thus, the retainer 7 rotates at half the speed of the pressure rotating member 9 and outputs the same.

<C: At the time of simultaneous input of the motor and the pressure input means> The combined output is output from the retainer 7 at half the relative rotation amount (differential amount and direction) of the rotor 6 and the pressure rotating member 9. .

On the outer periphery of the pressure input (rotation) member 9, there are provided input means (not shown), for example, a manually operated member, or a gear portion 9-3 for coupling to the output of another power means. Not only the gear connection with the gear portion 7-2, but also a pulley for driving a belt or a rubber roller or the like for performing connection by friction transmission may be provided.

The motor is fixed by the pressure holding member 11.
The motor is attached and fixed to a device to which the motor is applied by using a motor fixing screw hole 11-4 provided in the flange portion.

If there is no adverse effect on the vibration of the stator, it is also possible to provide a screw hole in the spacer 2 or the stepped portion 1-1 of the shaft 1 or to fix it by chucking, press-fitting, bonding or the like. It is.

FIG. 2 is a sectional view showing another embodiment. In this embodiment, members having the same functions as those shown in FIG. 1 are denoted by the same reference numerals, and in particular, members denoted by reference numerals 1 to 7 are completely the same as those in the embodiment of FIG. I do.

The feature of the present embodiment is that the pressure rotating member 9 is divided into a rotating part 90 and a ball race part 91, and the second friction washer 13 is separated during the separation.
The first friction washer 12 is interposed between the rotating part 90 and the elastic pressing member 10.

The pressure rotating member 9 includes a rotating portion 90 having a gear portion 9-3 and a ball race portion 91 having a V groove 9-1.
An engagement groove 91-1 is formed in the shaft portion of the ball race portion 91 along the axial direction, and an engagement protrusion protruding from the inner diameter portion of the second friction washer 13 is formed. 13-1 engages with the engagement groove 91-1 to prevent the second friction washer 13 from rotating. In addition, you may use a D cut hole or a two-way hole as a structure of a rotation stop.

The engagement between the projection 13-1 and the engagement groove 91-1 causes the second friction washer 13 to rotate relatively non-rotatably with respect to the ball race portion 91, and causes the first and second friction washers 12 to rotate. , 13 and the material of the pressure rotating member, as well as the contact area and the surface roughness, can be set widely.

By the way, when the input to the pressure rotating member 9 is abrupt or excessive and exceeds the output side load, the ball 8 and the ball race 6-2-1 are frictionally slid regardless of rolling. As a result, the relative revolving operation may occur, and the ball 8 and the ball race 6-2-1 may be worn and damaged.

However, in this embodiment, the frictional sliding force of the ball 8 is T ₁ , the slip force between the second friction washer 13 and the ball race 91 of the pressure rotating member 9 is T ₂ , and the first friction washer 12 and pressure rotating member 9
Assuming that the slip force between the rotating parts 90 is T ₃ , T ₁ >
T _2> By setting the friction force such that the relationship of T _3, it is possible to prevent the damage or the like.

[0031] In the mechanical design, it is set to common input T _i to pressure rotating member side in the range of _{T 2> T i> T 3} , the durability of the motor, reliability preferable. In addition,
In the present embodiment, in order to fix the sliding surface of the first friction washer 12 to the pressure rotating member 9 side, the same engagement projection 13-1 and engagement vertical groove as the second friction washer 13 are provided on the inner diameter side thereof. Although the first and second washers are provided, the frictional force setting between the first and second washers and the non-pressurized rotating member is set to T ₁ and T _2.
Between, is set between T ₂ and T _3, mass production for construction for non-rotating process by the engagement is unnecessary, made stable to obtain a friction force is somewhat complicated flame Kashiku balanced relationship Disadvantageous. (Correspondence between the invention and the embodiment) The flange portion 6-1 of the rotor 6 of the embodiment is a rotating member of the present invention, the ball race portion 6-2 is a ball race of the present invention, and the ball 8 is a ball of the present invention. In addition, the retainer 7 corresponds to the differential output member of the present invention, the elastic pressing member 10 corresponds to the pressing means of the present invention, and the pressing rotating member 9 corresponds to the external input member of the present invention.

[0032]

As described above, according to the present invention, the following effects can be obtained.

1. The differential mechanism can be incorporated in the components of the rod-shaped vibration wave motor and can be compactly integrated in the form of a rod without increasing the number of parts.

2. Therefore, versatility is large because adaptation to various uses is easy in form and it is most suitable for miniaturization of equipment.

3. In addition, since it is easy to structurally use and share parts with a simple rod-shaped vibration wave motor, it is possible to develop and produce both a motor alone and a drive device with a built-in differential mechanism at low cost.

4. Since the structure can be assembled from one direction, the assembly cost is low and the production by automatic assembly is easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a vibration wave motor according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shaft 8 ... Ball 2 ... Spacer 9 ... Pressure rotation member 3 ... Piezoelectric element 10 ... Elastic pressure member 4 ... Electrode 11 ... Pressure holding member 5 ... Stator 12 ... Friction washer 6 ... Rotor 13 ... Friction washer 7 ... Retainer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02N 2/16

Claims (1)

(57) [Claims] 1. An electro-mechanical energy conversion element is disposed between elastic vibrators, and the electro-mechanical energy conversion element is disposed in front of the element.
The elastic vibrator is sandwiched by a connecting shaft member , and an alternating electric field is applied to the electro-mechanical energy conversion element to excite a vibration wave in the elastic vibrator to move the rotating member forward.
Oscillating wave drive that rotates around the axis of the connecting shaft member
A ball race provided on the rotating member
Receiving the rotational force of the plurality of balls arranged in
The revolving force of the plurality of balls revolving pre Symbol ball upper race Te, rotational force about the axis of the connecting shaft member
A differential output member to obtain, the said ball differential output member
And the connecting shaft member is opposed to the ball race with the
Can rotate about the axis of
An external input member, connected to the connection shaft member,
The input member and the plurality of balls are applied in the direction of the rotating member.
Pressurizing means for pressing, the rotational force of the rotating member and the
The rotational force of the external input member and the differential output member are individually obtained.
Differential mechanism built-in vibration wave driving apparatus characterized by that.