JPH04131191U - ultrasonic motor - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the fixation of the stator to the substrate in an ultrasonic motor, to make the entire stator in a more uniform stress state, to improve the output efficiency of the motor, and to facilitate the assembly and disassembly of the stator. I made it possible to do it. [Structure] The stator 2 of the ultrasonic motor is formed so that the center side is thicker than the outer peripheral part, the center hole of the stator is inserted into the cylindrical part 4 protruding from the substrate 1, and the elastic ring 6 is inserted into the ring of the cylindrical part 4. By fitting into the shaped groove 5, the elastic ring 6 is brought into line contact with the peripheral edge of the center hole of the stator, thereby fixing the stator 2.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

In this invention, the rotor is pressed against the stator, and the traveling waves generated in the stator cause the rotor to Regarding ultrasonic motors that rotate This effectively generates a traveling wave of a predetermined wavelength.

0002

[Conventional technology]

Ultrasonic motors use high-frequency electricity to drive a large number of piezoelectric elements on one side of the stator. They are arranged at a pitch of 1/2 of the wavelength of the elastic waves generated by the pressure, or It polarizes the electric body. A large number of piezoelectric elements are divided into two sets with an interval of λ/4, Proceeds to the stator by applying high frequency voltages with a 90° phase difference to each It's creating waves. The rotor, which is in pressure contact with the other surface of the stator, is then moved by the traveling wave. It is designed to be rotated.

0003 The rotor contacts the stator at its outer periphery and is affected by the traveling waves of the stator. Since the stator is designed to rotate, it is necessary to generate traveling waves effectively in the stator. There is. Therefore, when fixing the stator to the board, it is necessary to Leave a gap between the outer periphery of the stator and the board, or apply uniform force to the entire stator against the board. The applicant has proposed a device that can be fixed (Utility Model Application Publication No. 2-136491). Publication No.). In other words, in that proposal, a protruding ring is provided on the stabilizer to stabilize the stabilizer. By fixing several parts of the iser to the board side with screws, the protruding ring can be attached to the stator. It is designed to be pressed against the board side. Also, in the above proposal, a ring-shaped protrusion is added to the board side. It also includes one in which a stator is pressed onto the stator.

0004

[Problem that the idea aims to solve]

In the conventional ultrasonic motor, a stabilizer is used to fix the stator to the board. There are some that are fixed with ring-shaped protrusions, but the stabilizers are also in several places. Since the stator is fixed with screws, it was difficult to make the stress state uniform throughout the stator. . Therefore, even if a predetermined high-frequency voltage is applied to the piezoelectric element, a predetermined vibration at a predetermined wavelength will not be generated. It is difficult to generate traveling waves and the rotor cannot be rotated with a specified output. was there. In addition, a protruding ring is formed on the stabilizer and it is fixed with screws. However, the manufacturing process took time and the assembly efficiency was not very good. Therefore, the present invention improves the fixation of the stator to the substrate to make the entire stator more uniform. This improves the output efficiency of the motor by creating a uniform stress state, as well as assembling the stator. The purpose is to facilitate disassembly.

[0005]

[Means to solve the problem]

In order to achieve the above-mentioned purpose, the present invention has been developed to A cylindrical part is provided protrudingly, and the tip of the cylindrical part is formed with a smaller diameter than the base side, and the small diameter of the cylindrical part is A ring-shaped groove is provided on the outer periphery near the base side of the stator, and the stator has a center hole side closer to the outer periphery. Form a thin wall, insert the center hole into a small diameter cylindrical part, and insert an elastic ring into the ring-shaped groove. The stator was fixed by fitting. The elastic ring can be formed into a circular, square, or triangular cross section. The reason why it is in line contact with the stator is that it does not adversely affect the vibration characteristics of the stator. desirable.

[0006]

[Effect]

In the above ultrasonic motor, the center hole of the stator is inserted into the cylindrical part of the board, and the elastic Since the stator is fixed to the cylindrical part by locking, the entire stator has a uniform stress state. It has become. Therefore, by applying a high frequency voltage to the piezoelectric material of the stator, The traveling wave generated in the rotor has a predetermined wavelength and a predetermined amplitude, and the traveling wave is efficiently transmitted to the rotor. It can be actuated and rotated. In addition, the fixing and disassembly of the stator to the board side is The process is easy as all you have to do is fit the ring into the ring-shaped groove or take it out. It's easy.

[0007]

【Example】

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the ultrasonic motor, a disk-shaped stator 2 is stacked on a substrate 1, and a The rotors 3 to which friction materials are bonded are stacked, and traveling waves are generated on the stator 2 as described below. The rotor 3 is rotated by this. In addition, stator 2 or low If appropriate friction is created between the two by selecting the material etc. of the tab 3, No friction material is required between the two. Stator 2 has a thick outer circumference and a thin inner circumference. It is formed in the flesh, with a central hole in the center. Also, the thick outer peripheral part of stator 2 A large number of radial protrusions 2a are provided on the surface in contact with the rotor 3, and the stator 2 has many protrusions 2a. The vibration of the traveling wave can be increased.

[0008] A cylindrical portion 4 is protruded from the center of the substrate 1, and the tip 4a of the cylindrical portion is closer to the base side 4b. It is formed to have a small diameter, and a ring-shaped groove 5 is formed on the outer periphery near the base side of the tip 4a. It will be done. The center hole of the stator 2 touches the upper end of the base side 4b from the tip side of the cylindrical part 4. The elastic ring 6 which is inserted into the ring-shaped groove 5 of the cylindrical part and cut at one point By being fitted, the periphery of the center hole of the stator 2 is fixed to the cylindrical portion 4. this In this case, since the elastic ring 6 has a circular cross section, the stator 2 and the elastic ring 6 There is a circumferential line contact with the stator 2, and the vibration characteristics of the stator 2 are maintained on the substrate 1 side in a good condition. held. Note that the cross-sectional shape of the elastic ring 6 may be square, triangular, etc. other than circular. Any cross-sectional shape that makes line contact with the stator 2 may be used.

[0009] In order for the rotor 3 to rotate in response to the traveling waves of the stator 2, the rotor 3 must be The rotor 3 needs to be in pressure contact with the rotor 2, and the rotor 3 is held in place by a disc spring 8 via a friction material 7. is pushed towards the data side. The base on the center side of the disc spring 8 is attached to the flange 9a of the output shaft 9. so that when the rotor 3 rotates, the output shaft 9 rotates together via the disc spring 8. It has become. Note that the output shaft 9 passes through each central hole of the rotor 3, stator 2, and substrate 1. The output shaft 9 is connected to a bearing 10 provided on the substrate 1 and a casing covering the upper part of the rotor 3. It is held by a thrust bearing 12 provided in a ring 11.

0010 The stator 2 is made of an elastic material, and its thick outer circumference is made of a piezoelectric material on the surface facing the substrate 1. 13 is glued. The piezoelectric body 13 is arranged in a ring shape, and the driving height applied to it is Polarization of multiple piezoelectric elements with a pitch of 1/2 of the wavelength λ of the elastic wave generated by a frequency voltage The plurality of piezoelectric elements are divided into two sets of piezoelectric body parts separated by 1/4λ. So applying high frequency voltages with a 90° phase difference to each of the two sets of piezoelectric parts. This causes a traveling wave of wavelength λ to be generated in the stator 2, and the traveling wave is The waves rotate the rotor 3 as described above.

[0011]

[Effect of the idea]

In the ultrasonic motor of this invention, the inner circumference of the stator is formed thinner than the outer circumference, and Insert the center hole at the center of the thin part into the cylindrical part protruding from the board and make a line tangent to the elastic ring. Since the stator is fixed by contact, the vibration characteristics of the stator are maintained well and the motor efficiency is improved. improves. To fix or remove the stator, insert the elastic ring into the cylinder on the board side. It is easy to assemble by simply fitting it into and removing it from the ring-shaped groove in the part. This makes the structure especially suitable for small motors.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of an ultrasonic motor according to the present invention.

FIG. 2 is a partially enlarged view of a stator fixing structure.

[Explanation of symbols]

1 board 2 stator 3 Rotor 4 Cylindrical part 5 Groove 6 Elastic ring

Claims (2)

[Scope of utility model registration request] Claim 1: A traveling wave is generated by applying a driving high frequency wave having a phase difference of 90° to two sets of piezoelectric parts bonded to one surface of the stator, and the rotor is brought into pressure contact with the other surface of the stator. In an ultrasonic motor that is rotated by a traveling wave, the stator has a thicker piezoelectric bonding part on the outer periphery, a thinner wall on the center hole side, and a cylindrical part protruding from the center of the board on which the stator is attached. The tip of the cylindrical part is formed to have a smaller diameter than the base side, and a groove is provided on the outer periphery of the small diameter part of the cylindrical part near the base side, and the center hole of the stator is inserted into the small diameter part of the cylindrical part, and An ultrasonic motor characterized in that a stator is fixed to a cylindrical part by fitting an elastic ring with one end cut off. 2. The ultrasonic motor according to claim 1, wherein the elastic ring has a circular, square, or triangular cross section and is in line contact with the stator.