Double-constraint type radial transduction ultrasonic motor

Abstract

The invention provides a double-constraint radial transduction ultrasonic motor, which comprises an annular rotor and a plurality of stators distributed in the annular rotor in an annular array, and is characterized in that each stator comprises a metal elastomer, a left fixing hole, a right fixing hole, a left piezoelectric ceramic, a right piezoelectric ceramic and an elastic blade group for forming pre-pressure on the annular rotor, the working vibration mode of the stator is first-order standing wave type bending vibration, the left fixing hole and the right fixing hole are formed in the metal elastic body and are formed in the two wave node positions of the first-order standing wave type bending vibration respectively, namely, the amplitude is zero during vibration, and the elastic blade set comprises a left-end elastic blade, a middle elastic blade and a right-end elastic blade. The vibration asymmetry of the metal elastomer can be effectively improved, the structural rigidity of the motor can be improved, the output torque of the motor can be improved, the energy transmission efficiency and the driving capacity can be improved, and the overall performance of the motor can be remarkably improved.

Description

Technical Field

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

[0002] Currently, there are two design approaches for radial transducer ultrasonic motors. One approach uses the overall vibration of piezoelectric ceramics to drive the rotor rotation via elastic blades. This approach ensures consistent amplitude across all points on the stator's vibration surface, allowing for a larger number of elastic blades, but it requires a significant amount of ceramic. The other approach uses a combination of multiple stator units. Its advantage lies in the reduced amount of piezoelectric ceramics and the larger maximum amplitude of the stator's vibration surface. However, the varying amplitudes at different points on the stator's vibration surface impose significant limitations on the arrangement of the elastic blades. Multi-stator unit radial transducer ultrasonic motors have high requirements for constraint. Current literature focuses on two main types: end constraints and center-point constraints. Both constraint locations are situated at the points of maximum amplitude of the stator's elastic body. These design schemes place high demands on the constraint design and fabrication of the stator units. Structural and manufacturing errors can lead to asymmetrical vibration of the elastic body during motor operation, resulting in lower motor efficiency and output performance.

[0003] For example, Chinese invention application publication number CN116885971A discloses a radial transducer ultrasonic motor based on a centrally fixed arc-shaped stator unit. The motor constraint is applied at the point of maximum amplitude of the stator elastomer. Structural and processing errors can lead to large asymmetric vibrations, resulting in low motor efficiency and output performance. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-constraint radial transducer ultrasonic motor that solves the problems of uneven vibration mode distribution, asymmetric vibration of the elastic body, low energy transfer efficiency, and insufficient driving capability in the prior art.

[0005] The technical solution of this invention is: A dual-constraint radial transducer ultrasonic motor includes an annular rotor and several stators arranged in an annular array within the annular rotor. The stators include a metallic elastomer, a left fixing hole, a right fixing hole, a left piezoelectric ceramic, a right piezoelectric ceramic, and an elastic blade assembly that forms a preload on the annular rotor. The metallic elastomer is arc-shaped, and the left and right piezoelectric ceramics are respectively located on the left and right sides of the metallic elastomer. The stator's operating mode is a first-order standing wave bending vibration. The left and right fixing holes are respectively located on the metallic elastomer and at the two nodes of the first-order standing wave bending vibration, i.e., the amplitude is zero during vibration. The left, middle, and right ends of the surface of the metallic elastomer are respectively provided with a left mounting groove, a middle mounting groove, and a right mounting groove at the maximum amplitude positions. The elastic blade assembly includes a left-end elastic blade, a middle elastic blade, and a right-end elastic blade. 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.

[0006] Furthermore, both the left and right fixing holes are located at the radial half of the metal elastomer and at the circumferential 1 / 3 and 2 / 3 positions of the metal elastomer, respectively.

[0007] Furthermore, the lengths of the left-end elastic blade, the middle elastic blade, and the right-end elastic blade are all greater than the distance between the metal elastomer and the annular rotor.

[0008] Furthermore, the near-annular rotor ends on the left and right sides of the metal elastomer are respectively provided with a left protruding structure and a right protruding structure. The left protruding structure forms a left groove with the left side of the metal elastomer to accommodate the left piezoelectric ceramic, and the right protruding structure forms a right groove with the right side of the metal elastomer to accommodate the right piezoelectric ceramic.

[0009] Furthermore, the inclination directions of the elastic blade assembly and the left, middle, and right mounting grooves are all consistent with the rotation direction of the annular rotor, and the preload of the elastic blade assembly is generated by its own deformation.

[0010] Furthermore, based on several stators distributed in a circumferential ring array, multiple sets of stator groups with the same structure are arranged along the axial direction to form a combined stator structure connected in parallel along the axial direction.

[0011] Furthermore, the polarization directions of the left and right piezoelectric ceramics are both radial directions of the stator, but opposite. When an alternating electric field perpendicular to the polarization direction is applied, the left and right piezoelectric ceramics undergo torsional vibration under the influence of the same electric field. Their shear deformation directions are opposite, and the left and right protruding structures on the metal elastic body drive the metal elastic body to generate first-order standing wave bending vibration. The amplitude is largest at the ends and center of the metal elastic body. At these three locations, tilting structures in the same direction are arranged... The inclined elastic blade consists of the left elastic blade, the middle elastic blade, and the right elastic blade. When the stator vibrates, radial vibration is generated at the roots of the left, middle, and right elastic blades. The motion trajectories of the ends of the left, middle, and right elastic blades are all inclined ellipses, generating an inclined thrust on the annular rotor in the inclined direction of the elastic blade group. The radial component of the inclined thrust is outward along the radius, and the circumferential component is the inclined direction of the elastic blade group. The circumferential component of the inclined thrust drives the annular rotor to rotate along the inclined direction of the elastic blade group.

[0012] The beneficial effects of this invention are: I. This type of dual-constraint radial transducer ultrasonic motor, by designing a dual-channel structure at the two nodes where the amplitude of the metal elastomer is zero to apply constraint, can effectively improve the asymmetric vibration problem of the metal elastomer caused by constraint design and manufacturing process, thereby improving the structural rigidity of the motor and thus improving the efficiency and output performance of the motor. Simultaneously, this structure allows for smaller amplitude differences on the motor's vibration surfaces, enabling the arrangement of more elastic blades (up to three), increasing the motor's output torque, improving energy transfer efficiency and driving capability, and achieving a significant improvement in the overall performance of the motor.

[0013] Second, the dual constraint position of the present invention is located at the node position of the vibration mode of the metal elastomer. The amplitude at this position is zero. Therefore, the reaction force on the constraint structure during vibration is small. Compared with other constraint forms under the same process, it has less vibration asymmetry caused by constraint. The working state of the elastic blade group is closer to the ideal situation, and the energy conversion efficiency of the motor is higher.

[0014] Third, this type of double-constraint radial transducer ultrasonic motor, by applying constraints at the nodes along the radial 1 / 2 position and the circumferential 1 / 3 and 2 / 3 positions of the metal elastomer, and installing elastic blades at the three points of maximum amplitude at the end and center of the metal elastomer, adds two elastic blades to the stator unit compared to the end-fixed radial transducer ultrasonic motor, and one elastic blade compared to the center-constrained radial transducer ultrasonic motor. This enables the stator unit to form a more stable support during operation, improves the overall structural rigidity of the motor, realizes the arrangement of three elastic blades on the surface of the stator unit, enhances the stator amplitude and output torque, optimizes the power transmission path, improves the energy conversion efficiency and output performance of the motor, and ensures efficient operation of the motor under multiple working conditions. It has significant technical advantages and broad application prospects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the dual-constraint 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 when the left piezoelectric ceramic is excited 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; Wherein: 1-ring rotor, 2-metal elastomer, 3-left fixing hole, 4-right fixing hole, 5-left piezoelectric ceramic, 6-right piezoelectric ceramic, 7-elastic blade assembly, 8-left mounting groove, 9-middle mounting groove, 10-right mounting groove, 11-left protruding structure, 12-right protruding structure; 71-Left end elastic blade, 72-Middle elastic blade, 73-Right end elastic blade; 1L, 2L, 3L, 4L, 5L, 6L - the six degrees of freedom of the left piezoelectric ceramic, XYZ - the spatial coordinate system, E - the direction of the applied electric field, P1 - the polarization direction of the left piezoelectric ceramic, P2 - the polarization direction of the right piezoelectric ceramic. 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 radial transducer ultrasonic motor, such as Figure 1The system includes an annular rotor 1 and several stators arranged in a ring array within the annular rotor 1. Each stator includes a metallic elastomer 2, a left fixing hole 3, a right fixing hole 4, a left piezoelectric ceramic 5, a right piezoelectric ceramic 6, and an elastic blade assembly 7 that forms a preload on the annular rotor 1. The metallic elastomer 2 is arc-shaped. The left and right piezoelectric ceramics 5 and 6 are respectively located on the left and right sides of the metallic elastomer 2. The stator's operating mode is a first-order standing wave bending vibration. The left fixing hole 3 and right fixing hole 4 are respectively located on the metallic elastomer 2 and are arranged separately. The two nodes of the first-order standing wave bending vibration are respectively located at the maximum amplitude positions of the left, middle and right ends of the surface of the metal elastic body 2, which are respectively provided with left mounting groove 8, middle mounting groove 9 and right mounting groove 10. The elastic blade group 7 includes left elastic blade 71, middle elastic blade 72 and right elastic blade 71. The left elastic blade 71 is located at the left mounting groove 8, the middle elastic blade 72 is located at the middle mounting groove 9 and the right elastic blade 71 is located at the right mounting groove 10.

[0018] This type of dual-constraint radial transducer ultrasonic motor applies constraints by designing a dual-channel structure at the two nodes where the amplitude of the metal elastomer 2 is zero. This effectively improves the asymmetric vibration problem of the metal elastomer 2 caused by constraints and manufacturing processes, thereby increasing the structural rigidity of the motor and thus improving its efficiency and output performance. Simultaneously, this structure allows for smaller amplitude differences on the motor's vibration surfaces, enabling the arrangement of more elastic blades (up to three), increasing the motor's output torque, improving energy transfer efficiency and driving capability, and significantly enhancing the overall performance of the motor.

[0019] like Figure 2 The left fixing hole 3 and the right fixing hole 4 are both located at the radial half of the metal elastic body 2, and at the 1 / 3 and 2 / 3 positions of the circumference of the metal elastic body 2, respectively. These positions are the nodes of the working mode shapes of the metal elastic body 2. The left fixing hole 3 and the right fixing hole 4 serve as constraint points, providing axial constraints for the stator, and also providing radial constraints for the left fixing hole 3 and the right fixing hole 4.

[0020] The lengths of the left-end elastic blade 71, the middle elastic blade 72, and the right-end elastic blade 71 are all greater than the distance between the metal elastic body 2 and the annular rotor 1. When the metal elastic body 2 vibrates, the end trajectory of the elastic blade group 7 is an oblique ellipse, which in turn converts the vibration of the metal elastic body 2 into the rotational motion of the annular rotor 1.

[0021] This type of dual-constraint radial transducer ultrasonic motor has a left protruding structure 11 and a right protruding structure on the near-annular rotor 1 ends of the metal elastomer 2, respectively. The left protruding structure 11 forms a left groove with the left side of the metal elastomer 2 to accommodate the left piezoelectric ceramic 5, and the right protruding structure 12 forms a right groove with the right side of the metal elastomer 2 to accommodate the right piezoelectric ceramic 6. The left piezoelectric ceramic 5 and the right piezoelectric ceramic 6 are respectively bonded to the left and right grooves.

[0022] The inclination direction of the elastic blade assembly 7 and the left mounting groove 8, middle mounting groove 9 and right mounting groove 10 are all consistent with the rotation direction of the annular rotor 1. The preload of the elastic blade assembly 7 is generated by its own deformation. The roots of the left end elastic blade 71, the middle elastic blade 72 and the right end elastic blade 73 are fixed in the left mounting groove 8, the middle mounting groove 9 and the right mounting groove 10 respectively by welding or bonding, and their ends are in contact with the rotor.

[0023] This type of dual-constraint radial transducer ultrasonic motor consists of several stators connected in parallel along a circumference. The number of stators can be up to four. Based on a circumferentially arranged ring array of stators, multiple sets of stator groups with the same structure are arranged axially to form a combined stator structure connected in parallel along the axial direction, thereby achieving a larger torque output.

[0024] This type of dual-constraint radial transducer ultrasonic motor has three elastic blades on the surface of the metal elastomer 2, located at both ends and the middle of the metal elastomer 2. These positions are the maximum amplitude positions of the metal elastomer 2, thereby ensuring the output torque and working efficiency of the motor.

[0025] like Figure 3 , Figure 4 and Figure 5 The left piezoelectric ceramic 5 and the right piezoelectric ceramic 6 operate in the d15 shear vibration mode, and the left piezoelectric ceramic 5 and the right piezoelectric ceramic 6 will vibrate along their shear direction. Figure 3 In the middle, the black dotted line represents the torsional deformation of the piezoelectric ceramic 5 on the left. Figure 4 and Figure 5In the diagram, the solid black line represents the stator shape before deformation. The polarization directions P1 and P2 of the piezoelectric ceramics on the left and right sides are both radial directions of the stator, but in opposite directions. When an alternating electric field perpendicular to the polarization direction is applied, the piezoelectric ceramics 5 on the left and 6 on the right undergo torsional vibration under the action of the electric field in the same direction. The shear deformation directions of the piezoelectric ceramics 5 on the left and 6 on the right are opposite, and the left and right protruding structures on the metal elastic body 2 drive the metal elastic body 2 to generate a first-order standing wave bending vibration. The amplitude is largest at the end and center positions of the metal elastic body 2. An elastic blade is arranged at each of these three positions, namely the left elastic blade 71, the middle elastic blade 72, and the right elastic blade 73. All elastic blades are tilted in the same direction. When the stator vibrates, radial vibrations occur at the roots of the left-end elastic blade 71, the middle elastic blade 72, and the right-end elastic blade 73. The motion trajectory of the ends of all elastic blades is an oblique ellipse, generating an oblique thrust on the annular rotor 1 in the direction of the elastic blades' inclination. The radial component of the oblique thrust is outward along the radius, while the circumferential component is in the direction of the elastic blade group's inclination. The circumferential component of the oblique thrust drives the annular rotor 1 to rotate along the direction of the elastic blades' inclination, effectively converting the vibration of the arc-shaped stator into the rotational motion of the annular rotor 1. During this process, the arrangement of the left-end elastic blade 71, the middle elastic blade 72, and the right-end elastic blade 73, as well as the left fixing hole 3 and the right fixing hole 4, helps the stator maintain efficient operation under various load conditions, ensuring stability during the drive process.

[0026] This type of dual-constraint radial transducer ultrasonic motor constrains the stator unit at the wave nodes of the metal elastic body 2 and simultaneously adds elastic blades, which improves the vibration balance of the motor stator unit, enhances the rigidity of the stator unit, enables the motor to work efficiently under high-frequency vibration, reduces energy loss, and enhances driving capability, thus having high practical application value.

[0027] This type of dual-constraint radial transducer ultrasonic motor effectively solves the problems of complex structure, large volume, uneven vibration mode distribution, insufficient rigidity, low energy transfer efficiency and insufficient driving capability in the existing technology by fixing the stator at 1 / 2 of the radial direction and 1 / 3 and 2 / 3 of the circumferential direction at the nodes, and adding elastic blades at the middle position of the outer periphery of the arc-shaped stator unit, thereby achieving a significant improvement in the overall performance of the motor.

[0028] This type of dual-constraint radial transducer ultrasonic motor improves motor performance by designing a constraint structure for the arc-shaped stator unit at the double-node positions. Piezoelectric ceramics 5 on the left and pressure point ceramics on the right are located at both ends of the metallic elastomer 2. When a high-frequency electric field is applied, the piezoelectric ceramics undergo torsional vibration, and the metallic elastomer 2 responds by generating first-order bending vibration. The vibration of the metallic elastomer 2 is converted into the rotational motion of the rotor through the elastic blade assembly 7. The two fixing holes of the metallic elastomer 2 are located at the two nodes of the first-order bending vibration of the metallic elastomer 2, providing a more stable support for the stator during operation. This improves the overall structural rigidity of the motor while achieving the arrangement of three elastic blades on the surface of the stator unit, thereby increasing the stator amplitude and output torque, optimizing the power transmission path, and ensuring efficient operation of the motor under various working conditions.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dual-constraint radial transducer ultrasonic motor, comprising an annular rotor and a plurality of stators arranged in an annular array within the annular rotor, characterized in that: The stator includes a metallic elastomer, a left fixing hole, a right fixing hole, a left piezoelectric ceramic, a right piezoelectric ceramic, and an elastic blade assembly that forms a preload on the annular rotor. The metallic elastomer is arc-shaped. The left and right piezoelectric ceramics are respectively located on the left and right sides of the metallic elastomer. The stator's operating vibration mode is a first-order standing wave bending vibration. The left and right fixing holes are respectively located on the metallic elastomer and at the two nodes of the first-order standing wave bending vibration, i.e., the amplitude is zero during vibration. The left, middle, and right ends of the surface of the metallic elastomer are respectively provided with a left mounting groove, a middle mounting groove, and a right mounting groove at the maximum amplitude positions. The elastic blade assembly includes a left-end elastic blade, a middle elastic blade, and a right-end elastic blade. 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.

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

3. The dual-constraint radial transducer ultrasonic motor as described in claim 1, characterized in that: The lengths of the left-end elastic blade, the middle elastic blade, and the right-end elastic blade are all greater than the distance between the metal elastomer and the annular rotor.

4. The dual-constraint radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The left and right sides of the near-annular rotor end of the metal elastomer are respectively provided with a left protruding structure and a right protruding structure. The left protruding structure and the left side of the metal elastomer form a left groove for accommodating the left piezoelectric ceramic, and the right protruding structure and the right side of the metal elastomer form a right groove for accommodating the right piezoelectric ceramic.

5. The dual-constraint radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The inclination direction of the elastic blade assembly and the left, middle and right mounting grooves are all consistent with the rotation direction of the annular rotor. The preload of the elastic blade assembly is generated by its own deformation.

6. The dual-constraint radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: Based on several stators arranged in a circumferential ring array, multiple sets of stator groups with the same structure are arranged along the axial direction to form a combined stator structure connected in parallel along the axial direction.

7. The dual-constraint radial transducer ultrasonic motor as described in any one of claims 1-3, characterized in that: The polarization directions of the left and right piezoelectric ceramics are both radial to the stator, but opposite. When an alternating electric field perpendicular to the polarization direction is applied, the left and right piezoelectric ceramics undergo torsional vibration under the influence of the same electric field. Their shear deformation directions are opposite, and this vibration is caused by the left and right protruding structures on the metallic elastomer, which in turn drive the elastomer to produce a first-order standing wave bending vibration. The amplitude is greatest at the ends and center of the metallic elastomer. At these three locations, a single, inclined piece of elastomer is placed in the same direction. The elastic blades are the left-end elastic blade, the middle elastic blade, and the right-end elastic blade. When the stator vibrates, radial vibration is generated at the roots of the left-end elastic blade, the middle elastic blade, and the right-end elastic blade. The motion trajectories of the ends of the left-end elastic blade, the middle elastic blade, and the right-end elastic blade are all oblique ellipses, which generate an oblique thrust on the annular rotor in the direction of the tilt of the elastic blade group. The radial component of the oblique thrust is outward along the radius, and the circumferential component of the oblique thrust is the tilt direction of the elastic blade group. The circumferential component of the oblique thrust drives the annular rotor to rotate in the tilt direction of the elastic blade group.

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