JPH0775351A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To eliminate some uncertainty of transmission of rotation occurring when a load torque is large, in particular, on the occasion when the rotation of a moving body is transmitted to an intermediate member and a rotating shaft, in a vibration wave motor of a low-speed and high-torque type having the rotating shaft. CONSTITUTION:In a vibration wave motor equipped with a vibrator 2 which has a plurality of projections provided in a sliding part and a thin-plate fitting part for fitting provided on the neutral surface on the inside diameter part of a contact part, a moving body 107 which is in contact with the vibrator and rotated by a frictional drive given by a vibration wave of the vibrator 2 and a rotating shaft 10 which is so connected to the moving body 107 as to take out the rotation of the moving body, a thin-plate fitting part of the moving body 107 which comes into contact with the vibrator 2 is formed in the shape of a thin-plate ring or a thin-plate disk, while the moving body is connected directly to the rotating shaft 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention produces a progressive vibration wave in a vibrating body by applying a voltage to an electro-mechanical energy conversion element, and friction driving between the vibrating body and a moving body in contact therewith. The present invention relates to the structure of a vibration wave motor that causes relative movement, particularly a high torque and high precision vibration wave motor.

[0002]

2. Description of the Related Art FIG. 2 is a longitudinal sectional view of a conventional vibration wave motor,
3 is a front view of the vibrating body, FIG. 4A is an electrode configuration diagram, FIG. 4B is a developed side view of the stator, and FIG. 5 is a front view of the compression spring member.

In FIGS. 2, 3, and 4, 1 is a thickness b
Thin ring-shaped piezoelectric element of λ / 2 made of elastic material
(Where λ is the wavelength) 4 (integer multiples of 2) protrusions are formed at equal intervals over the entire circumference, and the solid electrode surface is fixed to the vibrating body 2. The piezoelectric element 1 and the vibrating body 2 constitute a stator. ing. As shown in FIG. 4 (a), the electrode structure on the other surface of the piezoelectric element 1 is polarized at λ / 2 pitches so as to have expansion / contraction polarities alternately opposite to the wavelength λ of the frequency to be excited. A driving electrode group (A _{1 to} A ₈ ) and B electrode group (B _{1 to} B ₈ ) and a λ / 4 pitch between these A and B electrodes for detecting the vibration state of each electrode group Of vibration detection electrodes S _A and S _B, and three other common electrodes G for grounding.

The drive B electrode group (B _{1 to} B ₈ ) is arranged at a pitch deviated by 3 / 4λ from the drive A electrode group (A _{1 to} A ₈ ), while the vibration detection electrode S _A is arranged. and S _B are a electrode group for driving (a ₁ to a ₈₎ and the B electrode group (B ₁ .about.B
₈ ), each of which is arranged around the substantially antinode position of the standing wave.

In FIG. 4B, the protrusion of the vibrating body 2 is formed by forming a slit having a constant width (t) with respect to the axis, where H is the total height of the vibrating body 2 and h is the slit depth. That's it.

Further, as shown in FIG. 4B, the central point of the vibration detecting electrodes S _A and S _B of the piezoelectric element 1 is aligned with the central point of the slit portion of the vibrating body 2 to form a stator. Therefore, the center points of the driving A electrode group (A _{1 to} A ₈ ) or the B electrode group (B _{1 to} B ₈ ) all coincide with the center point of the slit portion.

In the contact portion 2a of the vibrating body 2, four protrusions (integral multiple of 2) per λ / 2 formed by slits, a total of 72 protrusions, are formed at equal intervals over the entire circumference,
On the back surface, the piezoelectric element 1 is fixed concentrically with a heat-resistant epoxy adhesive at the slit position of the vibrating body 2 by specifying its electrode configuration.

A thin plate annular portion 2b is provided on the neutral surface of the contact portion 2a of the vibrating body 2 on the inner diameter side, and the thin plate annular portion 2b is provided.
3 have a plurality of mounting holes or mounting screws, and in the conventional example of FIG. 3, eight mounting holes 2d, which are integer multiples of 4, are arranged on concentric circles at equal intervals and at the angular position of the center of the slit of the vibrating body 2. And is concentrically fixed to the housing 3 made of a material having excellent thermal conductivity with a screw 4.

Since the vibrating body 2 is fixed to the housing 3 by the thin plate annular portion 2b on the inner diameter side of the contact portion 2a, the vibrating body 2 is rigidly supported, and the slits and the mounting as described above are provided. Since the holes are fixed with many screws, the internal stress generated by bending vibration is more uniform over the entire circumference.

The inner diameter fitting portion 3a at the center of the housing 3 has a first
The ball bearing 11 is provided by fixing the outer ring 11a.

Numeral 10 is a rotary shaft having a flange portion 10c fixed in the middle by, for example, shrink fit, and one end portion 10a thereof is supported by an inner ring of a first ball bearing 11 so as to be slidable in the axial direction. The other end portion 10b is a second portion provided by fixing an outer ring 12a to a bearing fitting portion 8a at the center of a housing cover 8 described later.
Is supported by the inner ring 12b of the ball bearing 12 so as to be slidable in the axial direction.

The other end 10b of the rotary shaft 10 is also provided with an inner diameter fitting portion 10c for fixing the output shaft of the encoder and a fixing screw 10d.

Numeral 15 is a disk-shaped intermediate member which is concentrically fixed to the flange portion 10c of the rotary shaft 10 with a screw 16, and an annular moving body 7 is concentrically fitted and provided on the outer peripheral portion. There is.

This moving body 7 is an annular sliding body b made of a composite resin, and a supporting body 5 made of, for example, an aluminum alloy in which the sliding body b is concentrically fixed to the thin plate annular portion 5a with an epoxy adhesive.
And the sliding body 6 contacts the contact portion 2b of the vibrating body 2.

The moving body 7 is supported by the intermediate member 15 via a rubber elastic sheet member 17 at the bottom thereof, and the flange portion 15a of the intermediate member 15 and the inner ring 12a of the second ball bearing 12 are connected to each other. The axial load generated by the diaphragm-shaped compression spring member 14 shown in FIG. 5, for example, provided between the two is supported by the elastic sheet member 17 in the axial direction of the support body 5 to contact the vibrating body 2. The portion 2b and the sliding body 6 of the moving body 7 are in pressure contact with each other.

Reference numeral 8 denotes the housing cover, which is fixed to the housing 3 with screws 9.

A spacer member (not shown) is installed in contact with the inner ring 12b of the second ball bearing 12 provided on the housing cover 8 to adjust the axial load generated by the compression spring member. Is.

[0018]

However, in the conventional vibration wave motor, a rubber elastic sheet member is used to connect the annular moving body composed of the sliding body and the supporting body to the rotary shaft for taking out the output, The movable body, the elastic sheet member and the intermediate member are connected by using the frictional force between the movable body and the elastic sheet member and between the elastic sheet member and the intermediate member by the action of the axial load by the compression spring member, and The intermediate member and the rotary shaft were directly connected.

For this reason, when transmitting the rotation of the moving body to the intermediate member and the rotating shaft, particularly when a large load torque is applied, there is a problem in reliability of rotation transmission.

Further, the conventional vibration wave motor is structurally complicated as described above, resulting in a large axial dimension and disadvantage in cost, and simplification of the structure has been desired. .

[0021]

Means for Solving the Problem (and Action) A structure for achieving the object of the present invention is to have a plurality of projections on the contact portion and a thin plate mounting portion for mounting on the inner diameter side neutral surface of the contact portion, A vibrating body that generates a vibrating wave, a moving body that is frictionally driven by the vibrating wave of the vibrating body that comes into contact with the vibrating body, and a rotating shaft that is connected to the moving body to take out the rotation of the moving body. In the vibration wave motor including, the moving body has a thin plate mounting portion formed on the inner diameter side of a sliding portion in contact with the vibrating body in a thin plate annular shape or a thin plate disk shape, and is directly connected to the rotary shaft. It is what is done.

Further, the moving body is brought into pressure contact with the vibrating body by a compression spring member arranged between the moving body and a bearing member supporting the rotating shaft.

With the above construction, the reliability of rotation transmission is improved, and an inexpensive vibration wave motor structurally simplified can be obtained.

[0024]

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

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

In FIG. 1, 1 is a piezoelectric element, 2 is a vibrating body, 3 is a housing, 4 is a screw, 6 is a sliding body, 9 is a screw and 10
2 is a rotary shaft, 11 is a first ball bearing, 12 is a second ball bearing, and 14 is a compression spring member.
Since it is equivalent to the conventional vibration wave motor, detailed description thereof will be omitted.

Numeral 10 is a rotary shaft having a flange portion 100c fixed in the middle by, for example, shrinkage fitting or adhesion, one end 10a of the inner ring 11b of the first ball bearing 11 and the other end 10b of the second ball bearing 12. The inner ring 12b is axially slidably and rotatably supported.

Reference numeral 107 denotes an annular sliding member 6 made of composite resin.
In the same manner as the conventional vibration wave motor, the sliding body 6 is a moving body formed of a support 105 made of, for example, an aluminum alloy, which is concentrically fixed to the thin plate annular portion 105a with a heat-resistant epoxy adhesive. The moving body 105 is concentrically fixed to the flange portion 100c of the rotary shaft 10 with a screw 116.

Since at least the sliding surface of the sliding body 6 made of the composite resin fixed to the supporting body 105 protrudes from the end surface of the supporting body 105, the sliding body 6 is attached to the supporting body 105.
It is possible to lap the sliding surface after fixing the.

Reference numeral 108 denotes a housing cover fixed to the housing 3 with screws 9, and a second ball bearing 12 is provided at the center of the housing cover.

Reference numeral 117 denotes a rubber elastic sheet member disposed on the other end surface of the moving body 107 for damping.

In the vibration wave motor of this embodiment shown in FIG. 1,
A moving body 107, in which a sliding body 6 made of a composite resin is fixed to a thin plate annular portion 105a, is directly connected to a flange portion 100c of the rotary shaft 10, and a rubber is provided between the moving body 107 and the inner ring 12a of the second ball bearing 12. The elastic sheet member 117 and the compression spring member 14 for pressurization are arranged.
Unlike the conventional example, the axial load generated by No. 4 is directly applied to the axial direction of the support body 105 without passing through the intermediate member, and the sliding body 6 of the moving body 107 is applied to the sliding surface 2b of the vibrating body 2. Pressure contact.

Although a radial ball bearing is shown as the second ball bearing 12 in FIG. 1, this may be replaced with a thrust type ball bearing.

FIG. 6 is a longitudinal sectional view showing a second embodiment of the vibration wave motor according to the present invention, in which 1 is a piezoelectric element, 6 is a sliding body,
9 is a screw, 10 is a rotating shaft, 11 is a first ball bearing, 1
Reference numeral 2 is a second ball bearing, 14 is a compression spring member, 108 is a housing cover, 117 is a rubber elastic sheet member, and the above components are equivalent to the vibration wave motor of the embodiment shown in FIG. The description is omitted.

Reference numeral 102 designates a vibrating body in which projections of an integral multiple of 2 per λ / 2 (2, 4, 6, ...) Are formed at equal intervals over the entire circumference, like the vibrating body 2 of the first embodiment. Although a thin plate annular portion 102b is provided on the neutral surface of the inner diameter side of 102a, it is an integral multiple of 4 (4, 8,
12 ...) No mounting hole corresponding to the mounting hole 2d
The vibrating body 102 is positioned by the mounting surface of 03, the fitting portion 103b, and a rotation stop pin (not shown), and the annular holding ring 13 is fixed by screwing it into the screw of the housing 103.

Reference numeral 207 is an annular sliding member 6 made of composite resin.
And a slide body 6 concentrically fixed to the end surface 205a of the outer diameter portion with a heat-resistant epoxy adhesive.
The moving body 207 is fixed to the outer diameter portion of the rotary shaft 10 directly by, for example, shrink fitting or bonding.

The support 205 has a thin disk portion 205b on the inner diameter side to which the slide body 6 is fixed.
Inner disk 1 of the thin disk portion 205b and the second ball bearing 12
The elastic sheet member 117 and the compression spring member 14 made of rubber are arranged between the vibrating body 102 and 2a, and the axial load of the compression spring member is applied in the axial direction of the thin disk portion 205b of the support 205 to slide the vibrating body 102. The sliding body 6 of the moving body 207 is brought into pressure contact with the surface 102b.

[0038]

As described above, in the vibration wave motor of the present invention, the moving body is directly connected to the intermediate member by using the frictional force between the moving body and the elastic sheet member and between the elastic sheet member and the intermediate member as in the conventional case. Since the moving body is directly connected to the flange of the rotating shaft or the rotating shaft instead of connecting the rotating shaft, the transmission of rotation is ensured even when the load torque is large.

Further, since the disk-shaped intermediate member is eliminated, structural simplification is possible and the axial dimension is reduced. And it became possible to provide an inexpensive vibration wave motor.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of a conventional vibration wave motor.

FIG. 3 is a front view of the vibrating body of FIG.

FIG. 4 shows the stator of FIG. 2, (a) showing the polarization direction of the piezoelectric element, and (b) showing a side view of the stator.

FIG. 5 is a front view of a compression spring member.

FIG. 6 is a vertical sectional view of a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric element 2, 102 ... Vibrating body 3, 103 ... Housing 5, 105, 2
05 ... Supporting body 6 ... Sliding body 7, 107, 2
07 ... Moving body 8, 108 ... Housing cover 10 ... Rotating shaft 14 ... Compression spring member

Claims (4)

[Claims] 1. A vibrating body which has a plurality of projections on the contact portion and a thin plate mounting portion for mounting on the inner surface of the contact portion on the inner diameter side, and a vibrating body which comes into contact with the vibrating body and vibrates. In a vibration wave motor including a moving body that is frictionally driven by the vibration wave of and a rotating shaft that is connected to the moving body so as to extract rotation of the moving body, the moving body contacts the vibrating body. A vibration wave motor characterized in that the thin plate mounting portion formed on the inner diameter side of the sliding portion is formed into a thin plate annular shape or a thin plate circular plate shape, and is directly connected to the rotary shaft. 2. The vibration wave motor according to claim 1, wherein the moving body makes pressure contact with the vibrating body by a compression spring member arranged between the moving body and a bearing member supporting the rotating shaft. 3. The vibration wave motor according to claim 1, wherein the moving body is directly fixed to an outer diameter portion of the rotary shaft. 4. The vibration wave motor according to claim 1, wherein a sliding body made of a composite resin is projected and fixed to one end surface of the moving body.