CN1207839C - Universal hollow-structure great-moment ring piezoelectric ultrasonic motor - Google Patents

Abstract

The general-purpose hollow structure high-torque annular piezoelectric ultrasonic motor belongs to the technical field of piezoelectric ultrasonic motors, and is characterized in that: the stator contains a metal ring with continuous comb-shaped driving teeth on the surface and an annular piezoelectric ceramic sheet; the rotor contains The metal rings, disc springs and rubber gaskets; the base contains standard ball bearings for spatial positioning of the central shaft and the base for spatial positioning of the stator; the shaft part contains a hollow central shaft, which is close to the shaft at one end of the rotor Key, ring washer and pre-tightening nut at the threaded part of the lower part of the central shaft; the reverse side of the above-mentioned ceramic sheet is polarized along the thickness direction, reversed every 1/2 wavelength, and the two sets of polarization intervals have a spatial difference of 1/4 wavelength or 3 /4 wavelength, the reverse side is grounded; the two sets of polarization intervals on the front side are respectively connected to two AC signals with a phase difference of 90 degrees, forming two sets of standing waves, and the two sets of standing waves are combined into traveling waves. There are screw holes on the central shaft, which are used to fix the executed part passing through the hollow part of the motor. It is versatile and the maximum output torque is greater than 5Kgfcm, and the speed is less than 120r/min.

Description

Universal Hollow Structure High Torque Ring Piezoelectric Ultrasonic Motor

technical field

The utility model relates to a general-purpose hollow-structure large-torque annular piezoelectric ultrasonic motor, which belongs to the technical field of piezoelectric ultrasonic motors.

Background technique

Piezoelectric ultrasonic motors are widely used as driving components of precision instruments due to their fast response speed, self-locking when power is off, no electromagnetic disturbance, and low-speed operation. There are two main types of ring piezoelectric motors in foreign countries: one is called ring piezoelectric motor because of the piezoelectric ceramic sheet with ring structure, but it does not have the characteristics of hollow structure. Fig. 1 is the structure of the annular piezoelectric ultrasonic motor developed by Japan Sashida, Matsushita and Canon, which mainly includes a rotor 11, a friction material 12, a stator 13 and a piezoelectric ceramic ring piece 14. The fixing methods of the stators all adopt a layer of soft rubber sheet under the piezoelectric ceramic sheet. Therefore, it is difficult to provide sufficient pre-tightening force between the stator and the rotor. When the outer diameter is 60mm, the maximum output torque of the motor is generally around 1Kgfcm. FIG. 2 shows the structure of the annular piezoelectric ultrasonic motor developed by Shinsei, which mainly includes a rotor 20 , a stator 21 , a shaft 22 , a preload adjustment mechanism 23 , a base 24 and a casing 25 . Wherein, the preload adjustment mechanism 23 includes an elastic disc 230 , a rubber washer 231 , an adjustment washer 232 and a shaft preload nut 233 . The rotor 20 includes a metal plate 201 and a friction material 202 . The stator 21 is composed of a metal disc 211 milled with teeth 2110 and an annular ceramic sheet 212 . In addition to the base itself, the base also has a shaft sleeve 241 and a bearing 242 . The stator 21 is mostly fixed on the inner circumference of the stator disc 211 with screws or other rigid simply supported methods, which is more suitable for adding a relatively large axial preload and provides the possibility to obtain a large output torque. When the outer diameter is about When the diameter is 60mm, the maximum output torque of the motor is generally around 6Kgfcm, but the structure of this ring piezoelectric motor is not hollow. The other abroad is the annular piezoelectric motor specially used for cameras. Its structure has the characteristics of hollow, and the light passes through the middle. However, the design of the motor itself is not based on general-purpose products. Its base and adjustment parts are all Used in conjunction with the camera lens, it is not universal, and its maximum output torque is not large. Thereby it does not possess the characteristics of versatility and high torque.

Contents of the invention

The object of the present invention is to provide a general hollow structure large torque piezoelectric ultrasonic motor for use as a driving element in precision machinery.

The present invention is characterized in that it contains: a stator, including a metal ring with continuous comb-shaped driving teeth on the surface and an annular piezoelectric ceramic sheet connected to the bottom of the metal ring; a rotor, including a metal ring whose bottom surface cooperates with the above-mentioned stator driving teeth Disc springs and rubber gaskets located on the upper end of the metal ring and pressed against the disc springs; base, including standard ball bearings for spatial positioning of the output shaft and bases for spatial positioning of the above-mentioned stator with inner holes Seat; output shaft, including a hollow central shaft, the central shaft is close to the shaft key at one end of the rotor, the ring washer and the pre-tightening nut at the threaded part near the lower end of the central shaft; the reverse side of the above-mentioned annular piezoelectric ceramic sheet is polarized along the thickness direction, each Half the wavelength is reversed once, the polarization interval of the piezoelectric ceramic is divided into two groups, the space difference between the two groups is 1/4 wavelength or 3/4 wavelength, the reverse side of the piezoelectric ceramic is a unified ground electrode, and Two AC signals with a phase difference of 90 degrees are respectively connected to the two groups of polarization intervals of the piezoelectric ceramic sheet. On the upper end of the central shaft close to the rotor, there is a screw hole for fixing the executed part passing through the hollow part of the motor. There is a flange for compressing the disc spring at the upper end of the central shaft near the disc spring.

Use proves that it serves its intended purpose.

Description of drawings

Fig. 1 is a structural schematic diagram of an existing annular piezoelectric ultrasonic motor.

Fig. 2 is the structural schematic diagram II of the existing annular piezoelectric ultrasonic motor.

Fig. 3 is a schematic structural diagram of a hollow annular piezoelectric ultrasonic motor according to an embodiment of the present invention.

Fig. 4 is a schematic structural view of the stator of the hollow annular piezoelectric ultrasonic motor according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of the polarization distribution of the annular piezoelectric ceramic sheet according to the embodiment of the present invention; a, front side; b, back side.

Fig. 6 is the actual vibration test result of the stator of the hollow annular piezoelectric ultrasonic motor according to the embodiment of the present invention.

Fig. 7 is a photo of the hollow ring piezoelectric ultrasonic motor of the embodiment of the present invention.

Detailed ways

Please see Figure 3 to Figure 5.

Fig. 3 is the general structure of this embodiment. It consists of a rotor part 30 , a stator part 31 , a base part 32 and a shaft part 33 . Wherein, the stator part 31 is composed of a metal ring 313 with comb-shaped driving teeth 310 and an annular piezoelectric ceramic sheet 314, and the annular piezoelectric ceramic sheet 314 is bonded to the bottom of the metal ring 313 by epoxy resin glue; the base part 32 has a base 321 with a fixed screw hole 3210, and its inner wall has a standard ball bearing 320 for positioning the central shaft 33; the rotor 30 is made up of a disc spring 300, a rubber sheet 301 and a metal ring sheet 302, and the rubber sheet 301 and the metal ring piece 302 are bonded with epoxy resin, and under the action of the disc spring 300, the metal ring piece 302 closely cooperates with the stator driving teeth 310, so that the rotor part 30 and the stator part 31 are in close contact; the shaft 33 includes : a shaft key 331 near the rotor 30, an annular washer 332 and a preload nut 333 near the thread 3301 at the lower end of the hollow central shaft 330, and four screw holes 3300 and A flange 3302, the function of the screw hole 3300 is to fix the executed part passing through the hollow part of the motor. The function of the flange 3302 is to compress the disc spring 300 . The output torque of the motor is transmitted to the central shaft 330 through the metal ring 302 in the rotor 30 , the rubber ring 301 , and the disk spring 300 , and then to the executed part through the screws in the screw holes 3300 .

Figure 4 is its stator structure. The stator 31 is mainly composed of an annular piezoelectric ceramic sheet 314 and a thinned metal ring 313 in the middle, and the two are connected with epoxy resin glue. There is a boss 312 on the inner ring of the stator 31, which sits in the inner hole of the base 321 and plays a role in positioning the stator 31 of the piezoelectric motor. The outer edge of the stator 31 has a comb-shaped tooth structure 310 , whose function is to amplify the vibration amplitude of the stator 31 . There are light holes 311 at the thinned part of the metal ring 313 , one of which needs to be screwed to fix the ground wire of the driving power supply, and the other light hole needs to be fixed circumferentially between the cylindrical positioning pin and the base 321 .

The partitions of the front and back of the piezoelectric ceramic ring piece 314 are shown in FIG. 5 . On the front, there are two input terminals of electrical signals SIN and COS with a time phase difference of 90 degrees, and an electrical signal feedback terminal reflecting the vibration state. The positive and negative signs on the reverse side of the piezoelectric ceramic sheet 314 represent the polarization direction of the corresponding ceramic region, and the piezoelectric ceramic ring sheet 314 is polarized along the thickness direction, and reverses every half wavelength. The polarization range of the piezoelectric ceramic sheet 314 is divided into two groups, and the spatial difference between the two groups is 1/4 wavelength or 3/4 wavelength. The reverse side of the piezoelectric ceramic 314 is a unified ground electrode, and on the front side, two AC signals with a phase difference of 90 degrees are respectively connected to two groups of polarization intervals of the piezoelectric ceramic sheet. The reverse side of the piezoelectric ceramic sheet 314 is bonded to the metal ring 313 .

A schematic diagram of the vibration test results of the stator of this embodiment is shown in FIG. 6 . This image is the test result of laser Doppler, and the two colors of one deep and one submerged respectively represent positive and negative vibrations along the thickness direction of the stator. This image is a series of standing waves formed by one of the SIN or COS on the stator 31 of the piezoelectric motor. When the same standing wave of another column with a spatial position difference of 1/4 wavelength is also formed on the stator, it will form a drive that can be realized. traveling wave. A photo of the corresponding hollow ring piezoelectric ultrasonic motor is shown in Fig. 7.

Its main performance parameters of the hollow structure annular piezoelectric ultrasonic motor of the present embodiment are as follows: the shape is round cake shape, the diameter of the stator is 62 mm, the thickness of the motor body is 20 mm, the internal hollow diameter of the motor is 20 mm, the shaft length is 55 mm, the diameter is 25 mm, and the operating frequency is 33 kHz ( 8 wavelengths) and 40kHz (9 wavelengths) can rotate both forward and reverse directions, the motor movement mode can be stepping and continuous rotation, the speed is less than 120r/min, and the maximum torque is greater than 5kgfcm.

Claims (3)

1, general hollow structure great-moment ring piezoelectric ultrasonic motor, comprise rotor, stator, base part and output shaft, it is characterized in that it contains: stator comprises that the surface has the becket of continuous pectination driving gear and is connected in the ring piezoelectric potsherd of this becket bottom; Rotor comprises the metal ring plate that the bottom surface cooperates with the said stator driving gear, disk spring and be positioned at this metal ring plate upper surface and pressurized in the rubber sheet gasket of this disk spring; Base part comprises to the sterically defined standard ball bearing of output shaft with endoporus said stator is carried out sterically defined pedestal; Output shaft comprises the central shaft of hollow, and this central shaft has the ring washer and the pre-load nut at screw thread place near the axle key of rotor one end near the central shaft lower end; Above-mentioned ring piezoelectric potsherd polarizes along thickness direction, every half wavelength oppositely once, be divided into two groups between the polarized area of this piezoelectric ceramic, the space differs 1/4 wavelength or 3/4 wavelength between two groups, the reverse side of this piezoelectric ceramic is unified grounding electrode, on its front, connecing phase difference between two groups of polarized areas of piezoelectric ceramic piece respectively is the two-way AC signal of 90 degree.

2, general hollow structure great-moment ring piezoelectric ultrasonic motor according to claim 1 is characterized in that: there is the screw hole that is performed part that fixedly passes the motor hollow space upper end at described central shaft near the rotor place.

3, general hollow structure great-moment ring piezoelectric ultrasonic motor according to claim 1 is characterized in that: have near the disk spring place in the upper end of described central shaft to compress the ring flange that disk spring is used.

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