WO2018077137A1

WO2018077137A1 - Ultrasonic motor

Info

Publication number: WO2018077137A1
Application number: PCT/CN2017/107321
Authority: WO
Inventors: 李文祺; 杨志勇; 杨云桂; 谢志; 周吉彬; 李炳华
Original assignee: 华为技术有限公司
Priority date: 2016-10-27
Filing date: 2017-10-23
Publication date: 2018-05-03
Also published as: CN206226321U

Abstract

Disclosed is an ultrasonic motor, which aims to solve the problem in the prior art that an ultrasonic motor has a great processing difficulty, is time-consuming in assembly and is easily damaged. The ultrasonic motor comprises a lower rotor (1). The centre of a side surface of the lower rotor (1) is provided with an assembly shaft (2), a stator (3) and an upper rotor (4) are sheathed on the assembly shaft (2), and the stator (3) is located between the upper rotor (4) and the lower rotor (1). A side surface, far away from the stator (3), of the upper rotor (4) is provided with an elastic piece (5), one end, far away from the lower rotor (1), of the assembly shaft (2) is provided with a clamping block (6) extending in a radial direction, and the elastic piece (5) is provided with an assembly hole (51) allowing the assembly shaft (2) and the clamping block (6) to pass through. When the elastic piece (5) is in a free state, a clearance between the clamping block (6) and the lower rotor (1) is less than a clearance between the elastic piece (5) and the lower rotor (1), and when the clamping block (6) passes through the assembly hole (51) and rotates relative to the elastic piece (5), the clamping block (6) can press the elastic piece (5) in a direction close to the lower rotor (1). The ultrasonic motor is used for providing a driving force.

Description

Ultrasonic motor

The present application claims priority to Chinese Patent Application No. PCT Application No. No. No. No. No. No. No. No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No

Technical field

The present application relates to the technical field of electric machines, and in particular to an ultrasonic motor.

Background technique

Ultrasonic motor is a drive that is driven based on the vibration of the ultrasonic frequency of functional ceramics. It is generally composed of a vibrating body (corresponding to a stator in a conventional motor, made of piezoelectric ceramics and a metal elastic material) and a moving body (equivalent to a conventional motor). The rotor is made of elastomer and friction material and plastic. When a high-frequency AC voltage is applied to the piezoelectric ceramic vibrator of the vibrating body, the stator is subjected to micro-mechanical vibration in the ultrasonic frequency band (frequency above 20 kHz) by using an inverse piezoelectric effect or an electrostrictive effect, and the vibration is passed through Resonance amplification and friction coupling are transformed into rotational or linear motion.

In order to realize the rotation of the ultrasonic motor, the rotor of the ultrasonic motor needs to provide a certain clamping force to the piezoelectric ceramic on the stator ring to rotate with the micro-mechanical vibration of the stator ring. As shown in FIG. 1, an ultrasonic motor is proposed in the prior art, including a stator 01 and an upper rotor 02 and a lower rotor 03 respectively disposed on both sides of the stator 01; and a surface of the lower rotor 03 on the side close to the stator 01 is provided with Shaft 04, shaft 04 is threaded. Both the stator 01 and the upper rotor 02 are sleeved on the shaft 04. After the nut 05 is tightened, the rotor can generate a certain clamping force against the stator 01, and the rotor can be rotated when the stator 01 generates vibration.

However, in the prior art ultrasonic motor, the shaft 04 passes through the stator 01 and then passes through the through hole in the center of the upper rotor 02, and then the shaft 04 is fixed by a Phillips screwdriver, and the nut 05 is tightened by a wrench. The assembly of the ultrasonic motor is fixed, but the assembly of the motor takes more than one minute and does not have mass production. In addition, in order to ensure the insulation performance, the shaft 04 generally selects a plastic material, and the cross groove is processed on the shaft 04 of the plastic material. When the thread is added, the shaft 04 may be disengaged from the lower rotor 03 during the machining process, resulting in low reliability of the shaft 04 and complicated machining process. However, if the shaft 04 is produced by a plastic-coated metal screw, the strength of the shaft 04 itself is increased, but there is also a problem that the machining process is complicated.

Summary of the invention

Embodiments of the present invention provide an ultrasonic motor that has high assembly efficiency, low processing difficulty, and high reliability.

In order to achieve the above object, an embodiment of the present invention provides an ultrasonic motor including a lower rotor, a center of one side surface of which is provided with a mounting shaft, and the mounting shaft is sleeved with a stator and an upper rotor, and The stator is located between the upper rotor and the lower rotor; a side surface of the upper rotor away from the stator is provided with a spring piece, and an end of the assembly shaft away from the lower rotor is provided to extend in a radial direction a clamping block, the elastic piece is provided with a mounting hole for allowing the assembly shaft and the card block to pass through, and when the elastic piece is in a free state, a gap between the clamping block and the lower rotor is smaller than the a gap between the spring and the lower rotor, when the block passes out of the assembly After the hole is rotated relative to the elastic piece, the block can press the elastic piece in a direction close to the lower rotor.

Compared with the prior art, in the ultrasonic motor provided by the embodiment of the present invention, one end of the assembly shaft on which the block is disposed passes through the stator and the upper rotor in sequence, and passes through the assembly hole on the elastic piece, and the block is opposite to the elastic piece. Rotating at a certain angle, the slider can be pressed near the side surface of the elastic piece, and the elastic piece will be deformed toward the lower rotor. Since the ultrasonic motor is in a fixed state during use, the restoring force generated after the deformation of the elastic piece is generated. The upper rotor is pressed toward the stator. At the same time, the restoring force generated by the deformation of the spring piece is transmitted to the lower rotor through the assembly shaft, and the lower rotor is pressed toward the position of the stator, so that the lower rotor and the upper rotor of the ultrasonic motor are generated on the stator. A certain clamping force is provided so that the stator transmits vibration to rotate the rotor. When the ultrasonic motor is assembled, the stator and the upper rotor are sequentially sleeved on the assembly shaft, and then the slider is rotated at a certain angle with respect to the elastic piece, and then the elastic piece is contacted and the elastic piece is pressed, and the assembly time is short. Moreover, since the ultrasonic motor does not need to be additionally processed on the assembly shaft, the strength of the assembly shaft is not lowered and the processing difficulty is low.

In a first possible implementation manner, in combination with the first aspect, a limited hole is formed in the elastic piece, and a finite position protrusion is disposed on a side surface of the elastic piece toward the elastic piece, and the limiting protrusion is rotated with the clamping piece relative to the elastic piece. The limiting protrusion can be engaged in the limiting hole to prevent the rotation of the block relative to the elastic piece. After the card block is rotated by a certain angle, the limiting protrusion is engaged in the limiting hole, so that the card block cannot be rotated relative to the elastic piece, thereby preventing the ultrasonic motor from rotating relative to the elastic piece to the mounting hole during use, thereby causing the ultrasonic motor to rotate relative to the elastic piece to the assembly hole during use. The clamping force of the rotor to the stator disappears and even detaches from the assembly shaft.

In a second possible implementation, in combination with the first possible implementation of the first aspect, the shape of the fitting hole is adapted to the cross-sectional shape of the block and the mounting shaft in the radial direction. Thereby, the opening area on the elastic piece is reduced as much as possible, thereby ensuring that the elastic piece can be pressed to generate sufficient resilience to act on the stator and the rotor.

In a third possible implementation, in combination with the second possible implementation of the first aspect, the direction of extension of the mounting aperture is perpendicular to the direction of extension of the limiting aperture.

In a fourth possible implementation, in combination with the first aspect, a plurality of blocks are circumferentially spaced apart along the same cross-sectional circumference of the assembly shaft. The fatigue of the block is reduced, and the block and the assembly shaft are prevented from being disengaged during use, thereby ensuring the service life of the ultrasonic motor.

In a fifth possible implementation, in combination with the fourth possible implementation of the first aspect, the plurality of blocks are evenly distributed over the assembly shaft. The clamping force generated by the deformation of the shrapnel to the stator and the rotor is evenly distributed, ensuring stable operation of the ultrasonic motor.

In a sixth possible implementation, in combination with the fifth possible implementation of the first aspect, the block is a rectangular block extending in a radial direction of the assembly axis.

In a seventh possible implementation, in combination with the sixth possible implementation of the first aspect, the assembly shaft is provided with two blocks.

In an eighth possible implementation, in combination with the first possible implementation of the first aspect, the side of the limiting projection adjacent the mounting shaft is fixedly attached to the mounting shaft. The limit protrusion is not only connected to the block, but also connected to the assembly shaft, which is not easy to fall off, ensuring stable operation of the ultrasonic motor.

In a ninth possible implementation, in combination with the first possible implementation of the first aspect, the block, the stop projection and the assembly shaft are integrally formed. One-piece molding avoids the joining process, reduces process steps and increases the strength of the joints between the structures.

DRAWINGS

The drawings used in the examples or the description of the prior art are briefly described below.

1 is a schematic structural view of an ultrasonic motor in the prior art;

2 is a schematic structural diagram of an ultrasonic motor according to an embodiment of the present invention;

3 is a schematic structural diagram of an upper rotor and a spring piece of an ultrasonic motor according to an embodiment of the present invention;

4 is a schematic structural view of a lower rotor and an assembly shaft of an ultrasonic motor according to an embodiment of the present invention;

Figure 5 is an enlarged view of a portion I of Figure 4;

6 is a schematic structural view of an assembly shaft of an ultrasonic motor assembled through an assembly hole according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a rotation of a card block relative to a spring piece during assembly of an ultrasonic motor according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The ultrasonic motor used in the embodiment of the present invention has a system architecture as shown in FIGS. 2 to 5, and includes a lower rotor 1. The center of one side surface of the lower rotor 1 is provided with a mounting shaft 2, and the assembly shaft 2 is provided with a stator. 3 and the upper rotor 4, and the stator 3 is located between the upper rotor 4 and the lower rotor 1; the side surface of the upper rotor 4 away from the stator 3 is provided with a spring piece 5, and the end of the assembly shaft 2 away from the lower rotor 1 is provided in the radial direction. The extending block 6 is provided with a mounting hole 51 for allowing the assembly shaft 2 and the block 6 to pass through. When the elastic piece 5 is in a free state, the gap between the block 6 and the lower rotor 1 is smaller than that of the elastic piece 5 and the lower rotor. The gap between the two, when the block 6 passes out of the fitting hole 51 and is rotated relative to the elastic piece 5, the block 6 can press the elastic piece 5 in the direction approaching the lower rotor 1.

In the ultrasonic motor provided by the embodiment of the present invention, one end of the assembly shaft 2 on which the block 6 is disposed passes through the stator 3 and the upper rotor 4 in sequence, and passes through the assembly hole 51 on the elastic piece 5, and the block 6 is opposed to the elastic piece. 5 rotating a certain angle, the slider 6 can be pressed near the surface of one side of the elastic piece 5, and the elastic piece 5 will be deformed toward the lower rotor 1. Since the ultrasonic motor is in a fixed state during use, the elastic piece is used. The restoring force generated after the deformation of the 5 will press the upper rotor 4 against the stator 3. At the same time, the restoring force generated after the deformation of the elastic piece 5 is transmitted to the lower rotor 1 through the assembly shaft 2, so that the lower rotor 1 is pressed toward the position of the stator 3. Thereby, the lower rotor 1 and the upper rotor 4 of the ultrasonic motor generate a certain clamping force against the stator 3, so that the stator 3 transmits vibration to rotate the rotor. When the ultrasonic motor is assembled, the stator 3 and the upper rotor 4 are sequentially sleeved on the assembly shaft 2, and then the slider 6 is rotated at a certain angle with respect to the elastic piece 5, and then the elastic piece 5 is contacted and the elastic piece 5 is pressed. It takes a short time. Moreover, since the ultrasonic motor does not need to be additionally processed on the assembly shaft 2, the strength of the assembly shaft 2 is not lowered and the processing difficulty is low.

When the upper rotor 4 drives the rotating process of the elastic piece 5, the frictional force is directly generated by the contact surface of the elastic piece 5 and the clamping block 6, and the frictional force includes the static friction force for keeping the elastic piece 5 and the blocking block 6 relatively static, and also includes making the blocking block 6 relatively When the dynamic friction force between the elastic piece 5 and the block 6 is greater than the static friction force, the movement of the block 6 relative to the elastic piece 5 occurs when the block 6 moves relative to the elastic piece 5 to the assembly hole 51. At the time, the pressing action of the slider 6 on the elastic piece 5 disappears, so that the clamping force of the rotor to the stator disappears, and the stator 3 cannot transmit the vibration to the rotor, resulting in the ultrasonic motor not working normally. To avoid this, as shown in Figure 3 to Figure 6. A limiting hole 52 is defined in the elastic piece 5, and the limiting block 7 is disposed on the side surface of the elastic piece 5 on the side surface of the elastic piece 5. The limiting protrusion 7 can be restrained by the locking block 7 after being rotated relative to the elastic piece 5. The 7 card is received in the limiting hole 52 to prevent the rotation of the block 6 relative to the elastic piece 5. After the limiting protrusion 7 is engaged in the limiting hole 52, if the dynamic friction between the elastic piece 5 and the blocking block 6 is greater than the static frictional force, the clamping block 6 tends to move relative to the elastic piece 5, but the limiting convexity The 7 card is connected to the limiting hole 52, and the hole wall of the limiting hole 52 abuts against the sidewall of the limiting protrusion 7, so that the limiting protrusion 7 cannot move relative to the block 6, thereby defining the block. The movement of 6 relative to the elastic piece 5 avoids the occurrence of a shutdown of the ultrasonic motor due to the disappearance of the clamping force during operation.

After the slider 6 is rotated through the mounting hole 51 and rotated by a certain angle, the lower surface of the block 6 presses the elastic piece 5 to deform the elastic piece 5, and the deformation of the elastic piece 5 excessively causes the elastic deformation of the elastic piece 5 to be transformed into plastic deformation. The position of the deformation cannot be recovered or even broken. To avoid this, as shown in Figs. 3 and 6, the shape of the fitting hole 51 is adapted to the cross-sectional shape of the block 6 and the fitting shaft 2 in the radial direction. The shape of the fitting hole 51 is adapted to the shape of the cross section of the combined structure of the block 6 and the mounting shaft 2. At this time, after the combined structure of the block 6 and the mounting shaft 2 passes through the fitting hole 51, the block 6 is rotated at an arbitrary angle. It can be ensured that the contact area of the side surface of the block 6 near the elastic piece 5 and the elastic piece 5 is the largest, and the pressing force generated by the block 6 on the elastic piece 5 is constant, so that the pressure on the unit area of the contact surface of the elastic piece 5 is averaged. Smaller, the deformation of the contact surface of the elastic piece 5 with the block 6 is small, and the deformation of the elastic piece 5 cannot be recovered or broken, and the stable operation of the ultrasonic motor is ensured.

The rotation angle of the slider 6 after passing through the fitting hole 51 is preferably 90° as shown in FIGS. 6 and 7, that is, the extending direction of the fitting hole 51 is perpendicular to the extending direction of the limiting hole 52. If the rotation angle of the card block 6 after passing through the mounting hole 51 is small, the distance between the limiting hole 52 and the mounting hole 51 is small, so that when the limiting protrusion 7 is engaged in the limiting hole 52, the card When the elastic piece 5 is pressed, the elastic piece 5 on the side close to the mounting hole 51 has a large deformation, and the elastic piece 5 has a large load, and the deformation is large, which is liable to be plastically deformed or even broken. When the rotation angle of the block 6 after passing through the mounting hole 51 is large, although the elastic piece 5 does not cause large deformation or breakage, the rotation of the block 6 relative to the elastic piece 5 during the assembly process is manually completed. The rotation of the human body with a large angle cannot be rotated once in place, and it needs to be carried out in stages, and the assembly takes time and effort. After the rotation angle of the card block 6 through the assembly hole 51 is set to 90°, the elastic piece 5 does not undergo plastic deformation or even fracture, and the rotation angle is more ergonomic, and the operator can rotate in place during the rotation.

After the slider 6 presses the elastic piece 5 to elastically deform the elastic piece 5, the restoring force of the elastic piece 5 also has a certain pressing effect on the clamping block 6 while clamping the stator 3 and the rotor, so as to avoid the elastic piece 5 to the clamping block 6 The squeezing action disengages the block 6 from the assembly shaft 2, as shown in Figs. 4 and 5, a plurality of blocks 6 are circumferentially spaced apart along the circumference of the same cross-section of the assembly shaft 2, so that the spring 5 is restored. The forces act on the different blocks 6, respectively, and the force on the single block 6 is small and is not easy to disengage.

When the slider 6 presses the elastic piece 5 to clamp the stator 3 and the rotor, the deformation closer to the elastic piece 5 at the block 6 is larger, and the larger the elastic deformation means the larger the clamping force, in order to avoid the clamping force distribution. The motor running is unstable due to the unevenness. As shown in FIG. 5, the plurality of blocks 6 are uniformly distributed on the assembly shaft 2. At this time, the deformation distribution of the slider 6 by the elastic piece 5 is relatively uniform, and the elastic piece 5 does not appear. The case where the deformation at the local position is too large and the deformation of the other portion is too small effectively ensures the stable operation of the ultrasonic motor.

Preferably, the block 6 is disposed as a rectangular block extending in the radial direction of the mounting shaft 2, as shown in FIGS. 4 to 7, the processing difficulty of the rectangular block is low and the between the block 6 and the elastic piece 5 can be increased. The contact area can effectively reduce the pressure on the unit area of the contact surface, and avoid plastic deformation or even breakage of the elastic piece 5.

The elastic piece 5 is provided with the mounting hole 51 and the limiting hole 52 to facilitate the assembly of the ultrasonic motor. However, the opening area of the elastic piece 5 is lower, and the elastic piece 5 is more likely to be plastically deformed during use. In order to avoid this, only two blocks 6 are provided on the assembly shaft 2, and as shown in Figs. 3 to 5, the two blocks 6 are evenly distributed on the same cross-sectional circumference of the assembly shaft 2. The distribution makes the opening area of the elastic piece 5 small, but it can ensure that the pressing force of the elastic piece 5 is evenly distributed without affecting the normal operation of the ultrasonic motor.

The limiting protrusion 7 disposed on the surface of the block 6 near the side of the elastic piece 5 interacts with the hole wall of the limiting hole 52 during use, thereby defining the relative position of the block 6 and the elastic piece 5, However, during the interaction between the side surface of the limiting protrusion 7 and the hole wall of the limiting hole 52, the connecting portion of the limiting protrusion 7 and the blocking block 6 is subjected to concentrated stress, so as to avoid the limiting protrusion 7 and The block 6 is disengaged. As shown in FIG. 5, the side of the limiting protrusion 7 close to the mounting shaft 2 is fixedly attached to the mounting shaft 2, which causes the limiting protrusion 7 to be connected not only to the block 6, but also to the assembly shaft. 2 connection, the limit protrusion 7 is not easy to fall off when subjected to concentrated stress.

If the block 6 is disengaged from the limiting protrusion 7 or the block 6 is disengaged from the assembly shaft 2, the normal operation of the ultrasonic motor will be affected. To avoid this, as shown in FIG. 5, the block 6 The limiting protrusion 7 and the assembly shaft 2 are integrally formed, the integral molding process avoids the joining process, reduces the process steps to a certain extent, and the integral molding process makes the card block 6, the limiting protrusion 7 and the assembly shaft 2 become one The overall component has a high connection strength between the structures.

Other configurations and the like of the ultrasonic motor according to the embodiment of the present invention are well known to those skilled in the art and will not be described in detail herein.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not limited thereto; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that The technical solutions described in the foregoing embodiments are modified, or the equivalents of the technical features are replaced. The modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

An ultrasonic motor comprising a lower rotor, a center of one side surface of the lower rotor is provided with a mounting shaft, the assembly shaft is sleeved with a stator and an upper rotor, and the stator is located at the upper rotor and the lower Between the rotors; a side surface of the upper rotor away from the stator is provided with a spring piece, wherein the end of the assembly shaft away from the lower rotor is provided with a block extending in a radial direction, the elastic piece An assembly hole allowing the assembly shaft and the block to pass through is opened, and when the elastic piece is in a free state, a gap between the block and the lower rotor is smaller than between the elastic piece and the lower rotor The gap may press the elastic piece in a direction close to the lower rotor when the block passes out of the mounting hole and rotates relative to the elastic piece.
The ultrasonic motor according to claim 1, wherein a limited hole is formed in the elastic piece, and the block is provided with a finite protrusion on a side surface of the elastic piece, and the limiting protrusion is provided After the slider is rotated relative to the elastic piece, the limiting protrusion can be engaged in the limiting hole to block the rotation of the block relative to the elastic piece.
The ultrasonic motor according to claim 2, wherein the shape of the fitting hole is adapted to a sectional shape of the block and the fitting shaft in the radial direction.
The ultrasonic motor according to claim 3, wherein the fitting hole extends in a direction perpendicular to the extending direction of the limiting hole.
The ultrasonic motor according to claim 1, wherein a plurality of said blocks are circumferentially spaced apart along the same cross section of said assembly shaft.
The ultrasonic motor according to claim 5, wherein a plurality of said blocks are evenly distributed on said assembly shaft.
The ultrasonic motor according to claim 6, wherein said block is a rectangular block extending in a radial direction.
The ultrasonic motor according to claim 7, wherein two of said blocks are disposed on said assembly shaft.
The ultrasonic motor according to claim 2, wherein a side of the limiting projection adjacent to the mounting shaft is attached to the mounting shaft.
The ultrasonic motor according to claim 2, wherein the block, the limiting projection, and the assembly shaft are integrally formed.