JPH0529295U - Ultrasonic motor - Google Patents

Abstract

(57) [Summary] [Object] In an ultrasonic motor, by improving the support structure between the rotor and the spring member, the vibration in the axial direction generated in the rotor is attenuated and the rotational efficiency of the rotor is improved. [Structure] In an ultrasonic motor, a ring-shaped protrusion 4a is provided on the surface of a rotor 4 on the side of a spring member.
The base of the spring member is supported by a, and the spring member presses the rotor 4 to the stator 2 side through the ring-shaped protrusion 4a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ultrasonic motor in which a rotor is pressed against a stator with a spring member so that the rotor and the spring member are integrally rotated by a traveling wave generated in the stator and a spring force acting on the rotor. This is an improved support structure for the members.

[0002]

[Prior Art]

 In a conventional ultrasonic motor, a rotor laminated on one surface of a stator is pressed into contact with, for example, a ring-shaped member, and two sets of piezoelectric elements bonded to the other surface of the stator are provided with high-frequency waves having different phase differences. A traveling wave is generated in the stator by applying a voltage, and a frictional force in the traveling wave direction is generated in the rotor due to the traveling wave in the stator and the spring force acting on the rotor. The spring member was rotating. In the conventional ultrasonic motor configured as described above, the support structure of the rotor and the spring member is, as shown in FIG. 2, simply by pressing the base portion of the spring member 5 against the surface of the rotor 4 on the spring member side. It was only adopted.

[0003]

[Problems to be solved by the device]

 In the above-mentioned conventional ultrasonic motor, the support structure of the spring member and the rotor is such that the base of the spring member is simply brought into pressure contact with the surface of the rotor, and any fixing means is provided between the two. I didn't. Therefore, the base of the spring member slides on the surface of the rotor as the amplitude of the traveling wave generated in the stator changes, and the point of application of the spring force acting on the rotor changes. As a result, the rotor vibrates in the axial direction and the frictional force in the traveling wave direction generated therewith is reduced, causing problems such as hindering an increase in the rotational torque of the rotor.

Therefore, the present invention provides an ultrasonic motor capable of improving the rotation efficiency of the rotor by attenuating the axial vibration generated in the rotor by improving the support structure of the rotor and the spring member. The purpose is to provide.

[0005]

[Means for Solving the Problems]

 According to the present invention, the rotor is placed on one side of the stator and the spring member presses the rotor to the side of the stator, and two sets of piezoelectric element groups are bonded to the other side of the stator so that the piezoelectric element groups of each set are connected to each other. The above object is achieved in an ultrasonic motor in which a rotor and a spring member can be integrally rotated by applying high-frequency voltages having different phases to each other to generate traveling waves in the stator. The feature is that a ring-shaped protrusion is provided on the surface of the rotor on the spring member side, and the base of the spring member is supported by this ring-shaped protrusion.

[0006]

[Action]

 In the ultrasonic motor of the above means, since the base of the spring member is supported by the ring-shaped projection provided on the surface of the rotor, even if the amplitude of the traveling wave generated in the stator changes, the conventional spring member The base does not slide on the surface of the rotor. That is, since the point of action of the spring force exerted on the rotor by the spring member does not change, axial vibration of the rotor is damped. Therefore, since it is difficult to reduce the frictional force generated in the rotor in the traveling wave direction, the rotation efficiency of the rotor is improved and the vibration mode can be set accurately. The pressing force of the spring member is changed by adjusting the output and the frictional force, but this adjustment is easy because the base of the spring member is supported by the ring-shaped protrusion. Furthermore, it is possible to easily respond to changes in spring force due to long-term use. In addition, the ring-shaped protrusion increases the rigidity of the rotor, making it difficult to transmit the vibration of the outer peripheral portion of the rotor to the inner peripheral portion, thereby improving the motor efficiency.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to FIG. In the ultrasonic motor of the present invention, as shown in FIG. 1, a disk-shaped stator 2 is mounted on a substrate 1, and two sets of piezoelectric element groups 3a and 3b are attached to the surface of the stator 2 on the substrate 1 side by an adhesive material. To be glued. A disk-shaped rotor 4 is superposed on the side surface of the stator 2 opposite to the substrate 1 side. A ring-shaped protrusion 4a having the same central axis as that of the rotor 4 is provided on the surface of the rotor 4 opposite to the stator 2 side. The protrusion 4a has, for example, a base portion of a disc spring 5 (spring member). Is pressed. Then, as is well known, by applying a high frequency voltage having a 90 ° phase difference to each of the two piezoelectric element groups 3a and 3b, a traveling wave is generated in the stator 2 and the traveling wave is generated in the rotor 4. The working point of the coned disc spring 5 does not change, and the rotor 4 and the disc spring 5 rotate integrally. In this embodiment, the disc-shaped disc spring 5 is used as the spring member, but the present invention is not limited to this, and various spring members such as ring-shaped ones may be used.

A rotary shaft 6 is penetrated through the central holes of the base plate 1, the stator 2, the rotor 4, and the disc spring 5, and the rotary shaft 6 is provided with a bearing 7 a provided on the periphery of the central hole of the base plate 1. It is held by a bearing 7b provided in a casing 8 that covers the side surface of the stator 2. A ring-shaped holding member 9 is provided on the outer circumference of the rotary shaft 6, and the inner circumference of the disc spring 5 is fixed to the holding member 9, and when the rotor 4 rotates, the disc spring 5, and the holding member 9 The rotary shaft 6 also rotates integrally via the.

[0009]

[Effect of the device]

 In the ultrasonic motor of the present invention, the ring-shaped protrusion is provided on one surface of the rotor, and the base of the member is supported by this protrusion, so that the action point of the spring member generated in the stator does not change. Therefore, since the axial vibration of the rotor is attenuated, the rotation efficiency of the rotor is improved and the vibration mode can be set accurately.

[Brief description of drawings]

1 is a cross-sectional view showing an embodiment of an ultrasonic motor of the present invention.

FIG. 2 is a sectional view showing an embodiment of a conventional ultrasonic motor.

[Explanation of symbols]

 2 Stator 3a Piezoelectric element group 3b Piezoelectric element group 4 Rotor 4a Ring type protrusion 5 Disc spring (spring member)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinichiro Iwasaki 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Mukuro Aoyama 2-1-1 Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd. In the company

Claims (1)

[Scope of utility model registration request] 1. A rotor is superposed on one surface of a stator and is pressed against the stator side by a spring member, and two sets of piezoelectric element groups are adhered to the other surface of the stator so that the respective piezoelectric element groups are in phase with each other. In an ultrasonic motor in which a rotor and a spring member can be integrally rotated by applying different high-frequency voltages to the stator to generate a traveling wave, a ring-shaped protrusion is provided on the surface of the rotor on the spring member side.
An ultrasonic motor in which the base of a spring member is supported by the ring-shaped protrusion.