JPS62277078A - Piezoelectric motor - Google Patents

Abstract

PURPOSE:To reduce the loss of the drive of a piezoelectric motor by attaching a rotor to a rotational shaft, and integrally rotating the shaft, a pressure applying elastic unit and the rotor to eliminate the rotary load to the elastic unit. CONSTITUTION:A rotor 1 is attached to a rotational shaft 7 rotatable with respect to a stator 2. The stator 2 has a disclike supporting base 3 and a circular vibrating member 4 provided on the outer periphery. A vibration member 4 is secured through a piezoelectric element 5 and a buffer material 6 to the base 3. A circular elastic retainer 12 is secured to the end of the shaft 7, and an elastic unit 13 for pressing the member 4 on the rotor 1 is interposed between the retainer 12 and the rotor 1. The shaft 7, the unit 13 and the rotor 1 are integrally rotated.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Technical Field] The present invention relates to a piezoelectric motor that is frictionally driven by progressive vibration caused by a piezoelectric element.

[Background technology]

Conventionally, a piezoelectric motor that utilizes a piezoelectric element and is frictionally driven by progressive vibration is described in 1, "Nikkei Mechanical 1983.2.
There is one published in issue 28.

This type of Fj friction drive motor requires the rotating body to contact the stationary body with pressure. So-called pressurization is required.

For this reason, the configuration shown in FIG. 8 is adopted. That is, the support stand 8
The rotating body 8 is connected to the support shaft 82 provided in the rotary body 8 via a bearing 83.
4 is attached, and pressure is applied to the inner ring 83a of the hair ring 83 by a spring 85. The spring 85 is attached to the support shaft 82 by a spring stop 86.
It is locked to. 87 is an annular vibrating member that comes into contact with the rotating body 84, and has an annular piezoelectric element 88 adhered to the back surface thereof. The vibration member 87 is connected to the support base 8 via a cushioning material 89.
1, and the support base 81 and the vibrating member 87 constitute a fixed body 90.

The hair ring 83 is supported on the support base 8 by the force of the spring 85.
The rotating body 84 cannot be brought into pressure contact with the vibration member 87 of the fixed body 90 unless it slides slightly downward in the longitudinal direction of the support shaft 82 . Therefore, a narrow gap is provided between the inner ring 83a of the hair ring 83 and the support shaft 82.

However, the spring 85 is provided between the spring bearing 86 of the fixed support shaft 82 and the inner ring 83a, and the inner ring 83a is connected to the bearing 83.
Since the rotational load is applied through the zero sphere, if there is a sliding gap between the support shaft 82 and the inner ring 83a as described above, the spring 85 will receive a torsional force from the inner ring 83a. Therefore, the rotational driving force [ignition] occurs.

[Purpose of the invention]

An object of the present invention is to provide a piezoelectric motor that requires less FM loss of driving force when pressurization is achieved.

[Disclosure of the invention]

The piezoelectric motor of the present invention is a piezoelectric motor in which a fixed body and a rotating body are brought into pressure contact with each other, and the rotating body is rotated by frictional drive by exciting progressive vibration in the circumferential direction on the fixed body with a piezoelectric element, A rotary shaft is rotatably installed on the fixed body, the rotary body is attached to the rotary shaft so as to be movable in the axial direction but not rotatable, and the rotary member is attached to the fixed body between the rotary shaft and the rotary member. This is characterized by the provision of an elastic body for pressing.

According to the configuration of the present invention, the rotating body is attached to the rotating shaft that is rotatable with respect to the fixed body, and the rotating shaft, the pressurizing elastic body, and the rotating body rotate together, so that the elastic body No rotational load acts, reducing loss of driving force.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 and 2. In the figure, 1 is a disk-shaped rotating body, and 2 is a fixed body. The fixed body 2 includes a disk-shaped support 3 and an annular vibrating member 4 provided on its outer periphery, and a toric piezoelectric element 5 is adhered to the back surface of the vibrating member 4. Reference numeral 6 denotes a buffer material fixed to the support base 3 , and the vibration member 4 is fixed to the support base 3 via the piezoelectric element 5 and the buffer material 6 . Support stand 3
A rotary shaft 7 passes through the center of the rotary shaft 7 and is rotatably supported via a bearing 8. The bearing 8 may be a pole bearing or a sleeve bearing. hair ring 8
It is fixed to the rotating shaft 7 in the axial direction by a stopper 9. Although the retaining ring 9 is fitted into the circumferential groove of the rotating shaft 7, it may also be formed into a cylindrical shape and fixed to the rotating shaft 7 in the correct size. The upper end portion of the rotating shaft 7 is formed into a non-circular shaft portion 7a having a cross-sectional shape obtained by cutting off a portion of a circular shape as shown in FIG.
It penetrates into the rigging hole 10 in the center of. The fitting hole 10 of the rotating body I has a cross-sectional shape similar to that of the non-circular shaft portion 7a, but its inner diameter is larger than that of the non-circular shaft portion 7a to the extent that the rotating body 1 can be moved in the longitudinal direction relative to the rotating shaft 7. It is slightly larger. The non-circular shaft portion 7a may have an oval cross-sectional shape as shown in FIG. 3(A), or may have an axial groove 11 as shown in FIG. 3(B). . An annular elastic rod holder 12 is fixed to the tip of the rotating shaft 7, and this elastic rod holder I
An elastic body 13 is interposed between the rotating body 2 and the rotating body 1 to press the rotating body 1 into contact with the vibrating member 4.

The elastic body 13 is made of a compression coil spring and extends around the outer periphery of the rotating shaft 7. Note that the rotating body (2) does not necessarily have to be a single piece.

Operation Next, the operation of the above configuration will be explained. The piezoelectric element 5 excites progressive vibration in the circumferential direction in the vibrating member 4 of the fixed body 2.

At the apex of the progressive vibration, the mass point is moving in the opposite direction to the direction of vibration, so the rotating body 1, which is pressed against the vibrating member 4, rotates in the opposite direction to the direction of vibration. Since the rotating body 1 is axially movable with respect to the rotating shaft 7 and is pressed against the vibrating member 4 by the elastic body 13, a reliable drive can be obtained.

Moreover, since the rotating body 1 is fitted into the non-circular shaft portion 7a of the rotating shaft 7, it rotates together with the rotating shaft 7.

Since the elastic body 13 is provided between the rotating shaft 7 and the rotating body 1 that rotate together, no rotational load acts on the elastic body 13. Therefore, loss of one amount of driving force is reduced. Also,
In this embodiment, since members such as the elastic body 13 for pressurization are concentrated in the center, miniaturization can be easily achieved.

FIG. 4 shows a second embodiment. In this example, an annular elastic body storage recess 15 is provided at the center in the radial direction of the rotating body 1', and an elastic body 13' is housed in this. The upper end of the elastic body 13' is engaged with a disc-shaped elastic body receiver 12' fixed to the rotating shaft 7 with a retaining ring 16.
consists of a large diameter coil spring. With this configuration, since the elastic body 13' does not protrude above the rotating body 1',
Can be made thinner. In addition, instead of forming the elastic body storage recess 15 in an annular shape as described above, a plurality of elastic body storage recesses 15 may be arranged in the circumferential direction and each elastic body may be individually accommodated.

FIG. 5 shows a third embodiment. In this example, bearing 8
′ using a ball bearing, and the rotating body 1 of the inner ring 8a
An annular spacer 17 is provided on the side. The spacer 17 is fixed to the rotating shaft 7' and has a protrusion 17a, and by engaging the protrusion 17a with the recess 18 of the rotating body 1, the rotation of the rotating body 1 is transmitted to the rotating shaft 7'. . Therefore, the rotating shaft 7' is not provided with the aforementioned non-circular cross section. Note that the spacer 17 may be fixed to the inner ring 8a of the bearing 8'.

FIG. 6 shows a fourth embodiment. In this example, two bearings 8 of the first embodiment are used to prevent the rotating shaft 7 from wobbling.

FIG. 7 shows a fifth embodiment. In this example, a hair ring 8'' is used in place of the elastic body receiver 12 of the first embodiment. Both hair rings 8 and 8' use ball bearings. 19 is a support frame; It is fixed to the support base 3. In this configuration, two bearings 8#, upper and lower
, 8 supports the rotating shaft 7, so that the rotating shaft 7 is prevented from wobbling and the rotation accuracy is improved.

Note that in each of the second to fifth embodiments, the structural effects other than the above-mentioned contents are the same as in the first embodiment.

Further, in each of the embodiments described above, the vibrating members 4 are arranged in an annular manner, but vibrating members separated into rows of teeth may be arranged in an annular manner. Furthermore, the vibrating member 4 and the support base 3 may be integrated into one piece instead of being formed as separate members. The pressure 14 elements 56 are not limited to continuous annular elements.

〔Effect of the invention〕

In the piezoelectric motor of the present invention, the rotating body is attached to the rotating shaft that can freely rotate with respect to the fixed body, and the rotating shaft, the pressurizing elastic body, and the rotating body rotate together, so that the elastic body rotates. This has the effect that no load is applied and loss of driving force is reduced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, Fig. 2 is a cross-sectional view of a non-circular cross-section of the rotating shaft, and Fig. 3 (Δ), (B).
4 to 7 are sectional views of modified examples of the rotating shaft, respectively.
The figures are longitudinal sectional views of the second to fifth embodiments, and the eighth embodiment, respectively.
The figure is a longitudinal sectional view of a conventional example. ■... Rotating body, 2... Fixed body, 3... Support stand, 4
... Vibrating member, 5... Piezoelectric element, 6... Cushioning material,
7... Rotating shaft, 8... Hair ring, 12'... Elastic body holder, 13... Elastic body, 15... Elastic body housing recess Fig. 1 (A) (B) Fig. 2 Figure 3 Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) A piezoelectric motor in which a fixed body and a rotating body are brought into pressure contact with each other, and the rotating body is rotated by friction drive by exciting progressive vibration in the circumferential direction on the fixed body with a piezoelectric element. A rotating shaft is rotatably installed, the rotating body is attached to the rotating shaft so as to be movable in the axial direction but not rotatable, and an elastic body presses the rotating member against the fixed body between the rotating shaft and the rotating member. A piezoelectric motor characterized by being provided with. (2) A patent claim in which the rotating body is provided with an elastic body accommodating recess located in the middle in the radial direction, and the elastic body is accommodated in the elastic body accommodating recess and engaged with an elastic body holder provided on the rotating shaft. The piezoelectric motor according to the range (1) above.