Dual-constrained lightweight radial transduction type ultrasonic motor

Abstract

The application provides a double-constraint lightweight radial transduction type ultrasonic motor, which comprises a ring-shaped rotor and a plurality of stators arranged in a ring-shaped array in the ring-shaped rotor, wherein the stator is a hollow stator, and the stator comprises an arc-shaped hollow metal elastic body, a left fixing hole, a right fixing hole, a piezoelectric ceramic and an elastic blade group; the arc-shaped hollow metal elastic body is a metal elastic body with an arc-shaped hollow region extending in a circumferential direction formed in the interior of the metal elastic body; the piezoelectric ceramic is arranged on the left side and the right side of the arc-shaped hollow metal elastic body respectively; and the left fixing hole and the right fixing hole are arranged on the circumferential two sides of the arc-shaped hollow region respectively; the double-constraint lightweight radial transduction type ultrasonic motor can realize a significant lightweight design, can effectively improve the radial output amplitude of the stator, can improve the output torque while ensuring the operation stability, and can improve the overall working performance of the motor.

Description

Technical Field

[0001] This invention relates to a dual-constraint lightweight radial transducer ultrasonic motor, belonging to the field of ultrasonic motor technology. Background Technology

[0002] In the field of ultrasonic motor technology, traditional radial transducer ultrasonic motor stators often employ a solid, arc-shaped metallic elastomer structure. While this design offers advantages such as simple manufacturing processes and high structural strength, it often encounters unavoidable practical problems under actual high-frequency vibration conditions. Because the solid metallic elastomer has a relatively large overall bending stiffness in the radial direction, this increases its resistance to bending deformation. In this situation, the driving energy generated by the piezoelectric ceramic needs to be largely balanced by elastic potential energy when transferred into the metallic elastomer, making it difficult to effectively convert into the expected bending deformation. This results in limited radial output displacement on the stator's outer surface, consequently negatively impacting the motor's output torque performance.

[0003] For example, a radial transducer ultrasonic motor disclosed in Chinese invention patent publication number CN120880230A still has a traditional solid stator structure. This design not only has a large overall weight, resulting in a large inertia, but also, due to the high stiffness of the solid structure, the driving energy is difficult to be effectively converted into bending deformation, which leads to a bottleneck in further improving the radial output amplitude of its outer surface. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-constraint lightweight radial transducer ultrasonic motor to solve the problems of large weight and excessive solid stiffness that limit amplitude in the prior art.

[0005] The technical solution of this invention is: A dual-constraint lightweight radial transducer ultrasonic motor includes a rotor and several stators for driving the rotor. The stators are hollow stators, each including an arc-shaped hollow metal elastomer, a left fixing hole, a right fixing hole, piezoelectric ceramics, and several driving feet. The arc-shaped hollow metal elastomer is a metal elastomer with an arc-shaped hollow region extending circumferentially inside. Piezoelectric ceramics are respectively provided on the left and right sides of the arc-shaped hollow metal elastomer. The left and right fixing holes are respectively located on the circumferential sides of the arc-shaped hollow region, and the left and right fixing holes are respectively located at the two nodes of the first-order standing wave bending vibration of the stator. One end of the driving foot is connected to the arc-shaped hollow metal elastomer, and the other end of the driving foot abuts against the annular rotor.

[0006] Furthermore, by changing the radial position of the arc-shaped hollow region, the radial amplitude of the upper and lower surfaces of the arc-shaped hollow metal elastomer can be adjusted.

[0007] Furthermore, both the left and right fixing holes are located at the radial 3 / 8 position of the metal elastomer, and at the circumferential 1 / 3 and 2 / 3 positions of the metal elastomer, respectively.

[0008] Furthermore, by changing the radial installation positions of the left and right fixing holes, the radial amplitude of the upper and lower surfaces of the arc-shaped hollow metal elastomer can be adjusted.

[0009] Furthermore, the drive foot adopts an elastic blade assembly, which includes a left-end elastic blade, a middle elastic blade, and a right-end elastic blade. The left, middle, and right ends of the surface of the arc-shaped hollow metal elastomer are respectively provided with a left mounting groove, a middle mounting groove, and a right mounting groove. The left-end elastic blade is located at the left mounting groove, the middle elastic blade is located at the middle mounting groove, and the right-end elastic blade is located at the right mounting groove.

[0010] Furthermore, protruding structures are provided on the left and right sides of the arc-shaped hollow metal elastomer. The piezoelectric ceramics are radially and reversely polarized, and an alternating electric field perpendicular to the polarization direction is applied to generate shear elastic deformation in opposite directions. The protruding structures excite the arc-shaped hollow metal elastomer to generate first-order standing wave bending vibration, which in turn excites the root of each driving foot to generate radial motion, causing the free end of each driving foot to generate oblique elliptical trajectory motion, and the circumferential component of this motion drives the ring rotor to perform circular rotational motion.

[0011] Furthermore, the rotor is an annular rotor, and the stator and rotor achieve different rotation modes through different positional relationships: When the stator is arranged in a ring array within the ring rotor, and a driving foot is provided on the outside of the arc-shaped hollow metal elastomer, an external rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. When the stator is arranged in a ring array outside the ring rotor and a driving foot is provided on the inner side of the arc-shaped hollow metal elastomer, an inner rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. The stator is arranged in a ring array, and ring rotors are respectively arranged on the inner and outer sides of the stator. Drive feet are respectively provided on the inner and outer sides of the arc-shaped hollow metal elastomer. The drive foot 7 on the outer side of the arc-shaped hollow metal elastomer is deflected 30 degrees clockwise relative to the root along the radial normal direction of the outer surface of the arc-shaped hollow metal elastomer. The drive foot on the inner side of the arc-shaped hollow metal elastomer is deflected 60 degrees clockwise relative to the root along the tangent direction of the inner surface of the arc-shaped hollow metal elastomer, thus realizing a co-rotor dual-constraint lightweight radial transducer ultrasonic motor. The stator is arranged in a ring array, with ring rotors on the inner and outer sides of the stator respectively. Drive feet are provided on the inner and outer sides of the arc-shaped hollow metal elastomer. The drive feet on the outer side of the arc-shaped hollow metal elastomer are deflected 30 degrees clockwise relative to the root along the radial normal of the outer surface of the arc-shaped hollow metal elastomer, and the drive feet on the inner side of the arc-shaped hollow metal elastomer are deflected 60 degrees counterclockwise relative to the root along the tangent of the inner surface of the arc-shaped hollow metal elastomer. This realizes a lightweight radial transducer ultrasonic motor with opposite-direction dual rotors and dual constraints.

[0012] The beneficial effects of this invention are: this type of dual-constraint lightweight radial transducer ultrasonic motor... I. This type of dual-constraint lightweight radial transducer ultrasonic motor, by employing an arc-shaped hollow metal elastomer with an arc-shaped hollow region inside, achieves a significant lightweight design. While maintaining structural strength, it effectively reduces the stator's own weight, structurally lowering the overall mass of the stator and effectively increasing the stator's radial output amplitude. Simultaneously, the arc-shaped hollow region makes the node position of the first-order bending vibration more clearly defined. The left and right fixing holes, as dual-constraint fixing holes, are precisely positioned at this node, achieving a synergistic effect: on the one hand, the arc-shaped hollow region increases the amplitude; on the other hand, the node constraint avoids additional vibration interference caused by the increased amplitude. Thus, while increasing output torque, it ensures operational stability and improves the overall performance of the motor.

[0013] Second, the arc-shaped hollow region, left fixing hole, and right fixing hole of this invention possess flexible adjustment and optimization capabilities. By fine-tuning the radial distribution position of the arc-shaped hollow region, the stiffness distribution of the local structure can be altered, thereby effectively increasing the radial output amplitude of the stator. Simultaneously, by adjusting the radial distribution position of the left and right fixing holes, the amplitude correspondence between the upper and lower surfaces of the metal elastomer can be changed, achieving coordination with the inner and outer rotors. This further optimizes the vibration modes of the stator, achieving a synergistic increase in the output amplitude of the inner and outer surfaces of the stator, significantly improving the energy conversion efficiency.

[0014] Third, this type of dual-constraint lightweight radial transducer ultrasonic motor, by replacing the traditional solid structure with an arc-shaped hollow region, significantly reduces the weight of the stator itself and effectively lowers the radial bending stiffness of the metal elastomer, making it more prone to bending deformation. This ensures that the piezoelectric ceramic driving energy can be more effectively converted into the mechanical vibration of the elastomer, thereby significantly improving the radial output displacement of the stator's outer surface and the motor's output torque. Simultaneously, this invention effectively solves the defects of existing solid structures, such as large weight, high inertia, and limited amplitude. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the dual-constraint lightweight radial transducer ultrasonic motor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the stator structure in the embodiment; Figure 3 This is a schematic diagram illustrating the inverse piezoelectric effect during piezoelectric ceramic excitation in the embodiment; Figure 4 This is a schematic diagram of the deformation of the convex position of the metal elastomer during vibration in the embodiment; Figure 5 This is a schematic diagram of the deformation of the concave position of the metal elastomer during vibration in the embodiment; Figure 6 This is a schematic diagram of the inner rotor in the embodiment; Figure 7 This is a schematic diagram of the structure of the driving feet with the same tilt direction of the inner and outer dual rotors in the embodiment; Figure 8 This is a schematic diagram of the drive feet with opposite tilting directions of the inner and outer dual rotors in the embodiment; Wherein: 1-rotor, 2-arc hollow metal elastomer, 3-arc hollow area, 4-left fixing hole, 5-right fixing hole, 6-piezoelectric ceramic, 7-drive foot, 8-protruding structure, 9-left mounting groove, 10-middle mounting groove, 11-right mounting groove; 71-Left end elastic blade, 72-Middle elastic blade, 73-Right end elastic blade; 1L, 2L, 3L, 4L, 5L, 6L - six degrees of freedom of piezoelectric ceramics, XYZ - spatial coordinate system, E - direction of applied electric field, P1 - piezoelectric ceramic polarization direction on the left side of the arc-shaped hollow metallic elastomer, P2 - piezoelectric ceramic polarization direction on the right side of the arc-shaped hollow metallic elastomer. Detailed Implementation

[0016] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] The embodiment provides a dual-constraint lightweight radial transducer ultrasonic motor, such as Figure 1 The system includes a rotor 1 and several stators for driving the rotor 1. The stators are hollow stators and include an arc-shaped hollow metal elastomer 2, a left fixing hole 4, a right fixing hole 5, a piezoelectric ceramic 6, and several driving feet 7. The arc-shaped hollow metal elastomer 2 is a metal elastomer with an arc-shaped hollow region 3 extending circumferentially inside. Piezoelectric ceramics 6 are respectively provided on the left and right sides of the arc-shaped hollow metal elastomer 2. The left fixing hole 4 and the right fixing hole 5 are respectively provided on the circumferential sides of the arc-shaped hollow region 3, and the left fixing hole 4 and the right fixing hole 5 are respectively located at the two nodes of the first-order standing wave bending vibration of the stator. One end of the driving foot 7 is connected to the arc-shaped hollow metal elastomer 2, and the other end of the driving foot 7 abuts against the annular rotor 1.

[0018] This type of dual-constraint lightweight radial transducer ultrasonic motor achieves significant weight reduction through the use of an arc-shaped hollow metal elastomer 2 with an arc-shaped hollow region 3 inside. This design effectively reduces the stator's weight while maintaining structural strength, thus lowering the overall stator mass and significantly increasing the stator's radial output amplitude. Simultaneously, the arc-shaped hollow region 3 more clearly defines the node position of the first-order bending vibration. The left and right fixing holes 4 and 5, as dual-constraint fixing holes, are precisely positioned at this node, achieving a synergistic effect: on the one hand, the arc-shaped hollow region 3 increases the amplitude; on the other hand, the node constraint avoids additional vibration interference caused by the increased amplitude. This ensures operational stability while increasing output torque, thereby improving the overall performance of the motor.

[0019] This type of dual-constraint lightweight radial transducer ultrasonic motor adjusts the radial amplitude of the upper and lower surfaces of the arc-shaped hollow metallic elastomer 2 by changing the radial position of the arc-shaped hollow region 3. The left fixing hole 4 and the right fixing hole 5 are both located at 3 / 8 of the radial direction of the metallic elastomer, and respectively at 1 / 3 and 2 / 3 of the circumferential direction. By changing the radial installation positions of the left fixing hole 4 and the right fixing hole 5, the radial amplitude of the upper and lower surfaces of the arc-shaped hollow metallic elastomer 2 is adjusted.

[0020] like Figure 2 The driving foot 7 adopts an elastic blade assembly, which includes a left-end elastic blade 71, a middle elastic blade 74, and a right-end elastic blade 73. The left, middle, and right ends of the surface of the arc-shaped hollow metal elastomer 2 are respectively provided with a left mounting groove 9, a middle mounting groove 10, and a right mounting groove 11. The left-end elastic blade 71 is located at the left mounting groove 9, the middle elastic blade 74 is located at the middle mounting groove 10, and the right-end elastic blade 73 is located at the right mounting groove 11. The left and right sides of the arc-shaped hollow metal elastomer 2 are respectively provided with protruding structures 8. The piezoelectric ceramics 6 are radially and reverse-polarized, and an alternating electric field perpendicular to the polarization direction is applied to generate shear elastic deformation in opposite directions. The protruding structures 8 excite the arc-shaped hollow metal elastomer 2 to generate a first-order standing wave bending vibration, which in turn excites the root of each driving foot 7 to generate radial movement, causing the free end of each driving foot 7 to generate oblique elliptical trajectory movement, and the circumferential component of this movement drives the annular rotor 1 to perform circular rotational movement.

[0021] This type of dual-constraint lightweight radial transducer ultrasonic motor uses a ring rotor 1 as the rotor 1, and different rotation modes are achieved by different positional relationships between the stator and rotor 1: like Figure 2 When the stator is arranged in a ring array within the ring rotor 1, and a driving foot 7 is provided on the outside of the arc-shaped hollow metal elastomer 2, an external rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. like Figure 6 When the stator is arranged in a ring array outside the ring rotor 1 and a driving foot 7 is provided on the inner side of the arc-shaped hollow metal elastic body 2, an inner rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. like Figure 7 As shown, the stator is arranged in a ring array. The inner and outer sides of the stator are respectively equipped with ring rotors 1. The inner and outer sides of the arc-shaped hollow metal elastomer 2 are respectively provided with driving feet 7. The driving feet 7 on the outer side of the arc-shaped hollow metal elastomer 2 are deflected 30 degrees clockwise relative to the root along the radial normal direction of the outer surface of the arc-shaped hollow metal elastomer 2. The driving feet 7 on the inner side of the arc-shaped hollow metal elastomer 2 are deflected 60 degrees clockwise relative to the root along the tangent direction of the inner surface of the arc-shaped hollow metal elastomer 2, thereby realizing a co-rotor dual-constraint lightweight radial transducer ultrasonic motor. like Figure 8 As shown, the stator is arranged in a ring array, with ring rotors 1 arranged on the inner and outer sides of the stator respectively. Drive feet 7 are provided on the inner and outer sides of the arc-shaped hollow metal elastomer 2 respectively. The drive feet 7 on the outer side of the arc-shaped hollow metal elastomer 2 are deflected 30 degrees clockwise relative to the root along the radial normal of the outer surface of the arc-shaped hollow metal elastomer 2, and the drive feet 7 on the inner side of the arc-shaped hollow metal elastomer 2 are deflected 60 degrees counterclockwise relative to the root along the tangent of the inner surface of the arc-shaped hollow metal elastomer 2, thus realizing a counter-rotor dual-constraint lightweight radial transducer ultrasonic motor.

[0022] The implementation schemes for the above-mentioned inner rotor type dual-constraint lightweight radial transducer ultrasonic motor, co-rotor type 1 dual-constraint lightweight radial transducer ultrasonic motor, and counter-rotor type 1 dual-constraint lightweight radial transducer ultrasonic motor are similar to those for the outer rotor type dual-constraint lightweight radial transducer ultrasonic motor. For the dual rotor type 1 dual-constraint lightweight radial transducer ultrasonic motor, the output relationship between the inner rotor 1 and the outer rotor 1 can be adjusted by changing the positions of the fixing hole and the arc-shaped hollow region 3.

[0023] The rotor-type dual-constraint lightweight radial transducer ultrasonic motor, which is not included in the embodiments, is described below: like Figure 1The rotor 1 is an annular rotor 1. Based on several stators arranged in a circumferential annular array, multiple sets of stator groups with the same structure are arranged along the axial direction to form an axially parallel combined stator structure. The number of stators can be four. With the weight reduction design of the central arc-shaped hollow region 3, this axially parallel combined stator structure effectively controls the overall weight of the motor and improves the power density while increasing torque. The working vibration mode of the stator is a first-order standing wave bending vibration. The left fixing hole 4 and the right fixing hole 5 are respectively set on the metal elastic body and are respectively set at the two nodes of the first-order standing wave bending vibration, that is, the amplitude is zero during vibration. The arc-shaped hollow metal elastic body 2 has an arc-shaped hollow region 3 in the middle position, which can achieve weight reduction, reduce the equivalent thickness of the stator, and change the structural mass distribution of the stator; by changing the radial position of the arc-shaped hollow region 3, the overall vibration distribution of the stator is adjusted, thereby controlling the overall output amplitude of the stator. The circumferential span of the arc-shaped hollow region 3 is determined by the resonant frequency requirement of the stator, and the simulation shows that its circumferential span is 28 degrees.

[0024] like Figure 2 Because the embodiment incorporates an arc-shaped hollow region 3 in the center of the arc-shaped hollow metallic elastomer 2, the node positions of the first-order standing wave bending vibration are offset compared to the conventional structure without the hollow region. Finite element simulation optimization determined that the node positions are located at 3 / 8 of the radial direction of the arc-shaped hollow metallic elastomer 2 (rather than 1 / 2). Therefore, both the left fixing hole 4 and the right fixing hole 5 are located at 3 / 8 of the radial direction of the arc-shaped hollow metallic elastomer 2, and respectively at 1 / 3 and 2 / 3 of the circumference of the arc-shaped hollow metallic elastomer 2. These positions represent the node positions of the working mode vibration patterns of the arc-shaped hollow metallic elastomer 2. The left fixing hole 4 and the right fixing hole 5 serve as constraint points, providing axial constraints and radial constraints for the stator. By adjusting the radial distribution of the left fixing hole 4 and the right fixing hole 5, the amplitude correspondence between the upper and lower surfaces of the metallic elastomer can be changed, further optimizing the stator's vibration modes and significantly improving the energy conversion efficiency.

[0025] The left, middle, and right maximum amplitude positions of the arc-shaped hollow metal elastomer 2 are respectively provided with left mounting groove 9, middle mounting groove 10, and right mounting groove 11. The inclination direction of the elastic blade assembly and the left, middle, and right mounting grooves 9, 10, and 11 is consistent with the rotation direction of the annular rotor 1. Among them, the middle mounting groove 10 is located directly above the central arc-shaped hollow region 3. The preload of the elastic blade assembly is generated by its own deformation. The roots of the left-end elastic blade 71, the middle elastic blade 74, and the right-end elastic blade 73 are fixed in the corresponding mounting grooves by welding or bonding, and their ends are in contact with the rotor 1. The middle elastic blade 74 is located directly above the arc-shaped hollow region 3, and the lengths of the left-end elastic blade 71, the middle elastic blade 74, and the right-end elastic blade 73 are all greater than the distance between the arc-shaped hollow metal elastomer 2 and the annular rotor 1. When the arc-shaped hollow metal elastomer 2 vibrates, thanks to the optimization effect of the arc-shaped hollow region 3 on the vibration mode, the ends of the elastic blade assembly obtain a larger oblique elliptical trajectory displacement, thereby more efficiently converting the vibration of the arc-shaped hollow metal elastomer 2 into the rotational motion of the annular rotor 1. By strengthening the central amplitude through the central arc-shaped hollow region 3, good amplitude consistency is ensured between the middle elastic blade 74, the left elastic blade 71, and the right elastic blade 73, thus guaranteeing the output torque and working efficiency of the motor.

[0026] The arc-shaped hollow metal elastomer 2 has protruding structures 8 on the near-annular rotor 1 ends on both sides. The protruding structures 8 and the arc-shaped hollow metal elastomer 2 respectively form grooves for accommodating piezoelectric ceramics 6, and the piezoelectric ceramics 6 are respectively bonded to the grooves.

[0027] like Figure 3 , Figure 4 and Figure 5 The piezoelectric ceramic 6 operates in the d15 shear vibration mode and will vibrate along its shear direction. Figure 3 In the diagram, the black dashed line represents the torsional deformation of the piezoelectric ceramic 6, P1 indicates the polarization direction of the piezoelectric ceramic 6 on the left side of the arc-shaped hollow metallic elastomer 2, and P2 indicates the polarization direction of the piezoelectric ceramic 6 on the right side of the arc-shaped hollow metallic elastomer 2. Figure 4 and Figure 5In the diagram, the solid black line represents the stator shape before deformation. The piezoelectric ceramics 6 are polarized in opposite directions to the radial direction of the stator. When an alternating electric field perpendicular to the polarization direction is applied, the piezoelectric ceramics 6 undergo torsional vibration, with their shear deformation in opposite directions. This causes the arc-shaped hollow metal elastomer 2 to generate a first-order standing wave bending vibration through the protruding structure 8. During this vibration, the arc-shaped hollow region 3 in the middle of the arc-shaped hollow metal elastomer 2 optimizes the structural stiffness and reduces its mass, significantly enhancing the radial amplitude at the middle and both ends of the arc-shaped hollow metal elastomer 2. At each of these three maximum amplitude positions, an elastic blade tilted in the same direction is arranged. When the stator vibrates, thanks to the amplitude gain from the arc-shaped hollow region 3, the range of the oblique elliptical motion trajectory at the ends of all elastic blades is larger, thus generating a stronger oblique thrust on the annular rotor 1, biased towards the tilting direction of the elastic blades. The radial component of the oblique thrust extends outward along the radial direction, while the circumferential component drives the annular rotor 1 to rotate along the tilting direction of the elastic blades, efficiently converting the vibration of the arc-shaped stator into the rotational motion of the rotor 1. During this process, the left fixing hole 4 and the right fixing hole 5, located at the 3 / 8 radial node position, provide stable fulcrum constraints. Combined with the power enhancement effect of the arc-shaped hollow region 3, this ensures the efficient and stable operation of the motor under various load conditions.

[0028] This type of dual-constraint lightweight radial transducer ultrasonic motor constrains the stator unit at a node position at 3 / 8 of the radial direction of the arc-shaped hollow metal elastomer 2, and simultaneously improves the vibration balance of the motor stator unit by combining the arc-shaped hollow region 3 with the arrangement of three elastic blades. Utilizing the lightweight and amplitude enhancement effects brought about by the weight reduction zone, the motor can operate more efficiently under high-frequency vibration, reducing energy loss and significantly enhancing driving capability, thus possessing high practical application value.

[0029] This dual-constraint lightweight radial transducer ultrasonic motor effectively solves the problems of unsatisfactory vibration mode, amplitude limitation caused by excessive stiffness, and insufficient driving capability in the prior art by fixing it at 3 / 8 of the stator radial direction and 1 / 3 and 2 / 3 of the circumferential direction at the wave nodes, and by adding an arc-shaped hollow region 3 in the middle of the arc-shaped hollow metal elastomer 2. This achieves a significant improvement in the overall performance of the motor and a synergistic improvement in multiple performance aspects.

[0030] This type of dual-constraint lightweight radial transducer ultrasonic motor, when subjected to a high-frequency electric field, induces torsional vibration in the piezoelectric ceramic 6, causing the arc-shaped hollow metallic elastomer 2 to respond with first-order bending vibration. This vibration is then converted into rotational motion of the rotor 1 via the driving foot 7. During this process, the arc-shaped hollow region 3 plays a crucial role in weight reduction, significantly decreasing stator weight and mechanical inertia, and effectively increasing the radial output amplitude by altering the local stiffness distribution. Simultaneously, by fine-tuning the radial positions of the left and right fixing holes 4 and 5, not only can the output amplitude of the metallic elastomer be further increased, but the coordinated amplitude of the inner and outer surfaces of the metallic elastomer can also be achieved. In other words, the radial movement of the constraint holes serves a dual function of amplification and adjustment of the vibration relationship between the inner and outer surfaces. Combined with the weight-reduction amplification effect of the arc-shaped hollow region 3 and the amplitude adjustment function of the radial movement of the constraint holes, efficient driving of the three elastic blades on the stator unit surface is achieved. This reduces frictional losses, improves energy conversion efficiency, further enhances output torque, and optimizes the power transmission path.

[0031] The arc-shaped hollow region 3, left fixing hole 4, and right fixing hole 5 of this invention possess flexible adjustment and optimization capabilities. By fine-tuning the radial distribution position of the arc-shaped hollow region 3, the stiffness distribution of the local structure can be altered, thereby effectively increasing the radial output amplitude of the stator. Simultaneously, by adjusting the radial distribution position of the left and right fixing holes 5, the amplitude correspondence between the upper and lower surfaces of the metal elastomer can be changed, achieving coordination with the inner and outer rotors 1. This further optimizes the vibration modes of the stator, achieving a synergistic increase in the output amplitude of the inner and outer surfaces of the stator, significantly improving the energy conversion efficiency.

[0032] This type of dual-constraint lightweight radial transducer ultrasonic motor can not only effectively reduce the overall mass of the stator and achieve lightweighting, but also significantly increase the output amplitude of the metal elastomer under first-order bending vibration by changing the stiffness distribution in the middle, thereby playing an amplification role.

[0033] This dual-constraint lightweight radial transducer ultrasonic motor, by replacing the traditional solid structure with an arc-shaped hollow region 3, significantly reduces the stator's weight, achieving lightweight design and effectively lowering the radial bending stiffness of the metal elastomer, making it more prone to bending deformation. This ensures that the driving energy of the piezoelectric ceramic 6 can be more effectively converted into the mechanical vibration of the elastomer, thereby significantly improving the radial output displacement of the stator's outer surface and the motor's output torque. Simultaneously, this invention effectively solves the shortcomings of existing solid structures, such as large weight, high inertia, and limited amplitude.

[0034] This type of dual-constraint lightweight radial transducer ultrasonic motor features a fan-shaped structure in its arc-shaped hollow region 3, which significantly reduces the weight of the stator while making it easier for the stator to deform. By exciting the d15 shear vibration of the piezoelectric ceramics 6 on the left and right sides, the stator generates first-order standing wave bending vibration. Simultaneously, double circular hole constraints are set at the nodes of the first-order bending vibration of the metal elastomer to facilitate the fixation of the stator unit. By changing the radial positions of the left fixing hole 4 and the right fixing hole 5, the radial amplitude ratio and phase correspondence between the upper and lower surfaces of the metal elastomer can be adjusted, thereby coordinating the vibration output of the upper and lower surfaces to adapt to the dynamic cooperation of the inner rotor 1 and the outer rotor 1, respectively, achieving coaxial independent movement of the inner and outer rotors 1, common torque output, and mutual backup.

[0035] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, any improvements and modifications made without departing from the technical principles of the present invention, such as equivalent substitutions of the geometry of the arc-shaped hollow region 3 or reasonable movements of the constraint position of the fixing hole, should also be considered within the scope of protection of the present invention.

Claims

1. A dual-constraint lightweight radial transducer ultrasonic motor, comprising a rotor and a plurality of stators for driving the rotor, characterized in that: The stator is a hollow stator, which includes an arc-shaped hollow metal elastomer, a left fixing hole, a right fixing hole, a piezoelectric ceramic, and several drive feet. The arc-shaped hollow metal elastomer is a metal elastomer with an arc-shaped hollow area extending circumferentially inside. Piezoelectric ceramics are respectively provided on the left and right sides of the arc-shaped hollow metal elastomer. The left fixing hole and the right fixing hole are respectively located on the circumferential sides of the arc-shaped hollow area, and the left fixing hole and the right fixing hole are respectively located at the two nodes of the first-order standing wave bending vibration of the stator. One end of the drive foot is connected to the arc-shaped hollow metal elastomer, and the other end of the drive foot abuts against the annular rotor.

2. The dual-constraint lightweight radial transducer ultrasonic motor as described in claim 1, characterized in that: The radial amplitude of the upper and lower surfaces of the arc-shaped hollow metal elastomer can be adjusted by changing the radial position of the arc-shaped hollow region.

3. The dual-constraint lightweight radial transducer ultrasonic motor as described in claim 1, characterized in that: The left and right fixing holes are both located at 3 / 8 of the radial direction of the metal elastomer, and at 1 / 3 and 2 / 3 of the circumferential direction of the metal elastomer, respectively.

4. The dual-constraint lightweight radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The radial amplitude of the upper and lower surfaces of the arc-shaped hollow metal elastomer can be adjusted by changing the radial installation positions of the left and right fixing holes.

5. The dual-constraint lightweight radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The drive foot adopts an elastic blade assembly, which includes a left elastic blade, a middle elastic blade and a right elastic blade. The left, middle and right ends of the surface of the arc-shaped hollow metal elastomer are respectively provided with a left mounting groove, a middle mounting groove and a right mounting groove. The left elastic blade is located at the left mounting groove, the middle elastic blade is located at the middle mounting groove and the right elastic blade is located at the right mounting groove.

6. The dual-constraint lightweight radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The arc-shaped hollow metal elastomer has protruding structures on both sides. The piezoelectric ceramics are radially and reversely polarized, and an alternating electric field perpendicular to the polarization direction is applied to generate shear elastic deformation in opposite directions. The protruding structures excite the arc-shaped hollow metal elastomer to generate first-order standing wave bending vibration, which in turn excites the root of each driving foot to generate radial motion, causing the free end of each driving foot to generate oblique elliptical trajectory motion, and the circumferential component of this motion drives the ring rotor to perform circular rotation motion.

7. The dual-constraint lightweight radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The rotor is an annular rotor, and different rotation modes are achieved by different positional relationships between the stator and the rotor: When the stator is arranged in a ring array within the ring rotor, and a driving foot is provided on the outside of the arc-shaped hollow metal elastomer, an external rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. When the stator is arranged in a ring array outside the ring rotor and a driving foot is provided on the inner side of the arc-shaped hollow metal elastomer, an inner rotor type double-constraint lightweight radial transducer ultrasonic motor is realized. The stator is arranged in a ring array, and ring rotors are respectively arranged on the inner and outer sides of the stator. Drive feet are respectively provided on the inner and outer sides of the arc-shaped hollow metal elastomer. The drive foot 7 on the outer side of the arc-shaped hollow metal elastomer is deflected 30 degrees clockwise relative to the root along the radial normal direction of the outer surface of the arc-shaped hollow metal elastomer. The drive foot on the inner side of the arc-shaped hollow metal elastomer is deflected 60 degrees clockwise relative to the root along the tangent direction of the inner surface of the arc-shaped hollow metal elastomer, thus realizing a co-rotor dual-constraint lightweight radial transducer ultrasonic motor. The stator is arranged in a ring array, with ring rotors on the inner and outer sides of the stator respectively. Drive feet are provided on the inner and outer sides of the arc-shaped hollow metal elastomer. The drive feet on the outer side of the arc-shaped hollow metal elastomer are deflected 30 degrees clockwise relative to the root along the radial normal of the outer surface of the arc-shaped hollow metal elastomer, and the drive feet on the inner side of the arc-shaped hollow metal elastomer are deflected 60 degrees counterclockwise relative to the root along the tangent of the inner surface of the arc-shaped hollow metal elastomer. This realizes a lightweight radial transducer ultrasonic motor with opposite-direction dual rotors and dual constraints.

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