Unlockable inchworm rotary motor, redundant driving mechanism, and unlocking method

Abstract

The present disclosure relates to the technical field of inchworm rotary motors, and provides an unlockable inchworm rotary motor, a redundant driving mechanism, and an unlocking method. The present disclosure comprises: a wall; a rotatable output shaft; a drive module, which is directly or indirectly provided on the wall and drives rotation of the output shaft; an unlocking apparatus for disengaging the drive module from the output shaft in an unlocked state, the unlocking apparatus comprising: a fixedly arranged unlocking member, and an unlocking unit directly or indirectly arranged on one of the wall or the unlocking member, wherein there is a gap between the unlocking member and the output shaft, the unlocking unit is provided with an unlocking surface, and the unlocking surface is configured to be movable in a radial direction of the output shaft so as to at least partially abut against the other of the wall or the unlocking member; the wall is configured such that when the unlocking surface abuts against the other of the wall or the unlocking member, and the unlocking unit further moves in the radial direction of the output shaft and applies a force to the other of the wall or the unlocking member, the wall carries the drive module along, disengaging the drive module from the output shaft.

Description

Unlockable inchworm-type rotary motor, redundant drive mechanism and unlocking method

[0001] This application claims priority to Chinese Patent Application No. 202411480514.1, filed on October 23, 2024, entitled "Unlockable Inchworm Rotary Motor, Redundant Drive Mechanism and Unlocking Method", which was filed with the China Patent Office. Technical Field

[0002] This specification relates to the technical field of inchworm-type rotary motors, and in particular to an unlockable inchworm-type rotary motor, a redundant drive mechanism, and an unlocking method. Background Technology

[0003] The inchworm-type rotary motor is driven mainly by two sets of internal drive legs performing a "clamp-drive-release" action on the output shaft. During the manufacturing of this type of motor, it is necessary to ensure that a certain pre-pressure is applied to the internal drive legs. Therefore, when the motor is not powered on, the drive legs are clamped to the output shaft, causing the output shaft to self-lock. Moreover, this self-locking force is often greater than the driving force, so even if the motor system has a redundant design, the redundant motor cannot unlock. Summary of the Invention

[0004] This specification provides one or more embodiments of an unlockable inchworm-type rotary motor to solve the self-locking problem of inchworm-type rotary motors. The motor includes a wall; a rotatable output shaft; a drive module directly or indirectly disposed on the wall for driving the output shaft to rotate; and an unlocking device for disengaging the drive module from the output shaft in an unlocked state. The unlocking device includes: a fixedly disposed unlocking member; and an unlocking unit directly or indirectly disposed on one of the wall and the unlocking member, wherein there is a gap between the unlocking member and the output shaft, and the unlocking unit has an unlocking surface configured to move radially along the output shaft to at least partially abut against the other of the wall and the unlocking member. The wall is configured such that when the unlocking surface abuts against the other of the wall and the unlocking member, further radial movement of the unlocking unit along the output shaft and application of force to the other of the wall and the unlocking member can disengage the wall, carrying the drive module, from the output shaft.

[0005] According to some embodiments of this specification, an unlockable inchworm-type rotary motor is provided, wherein the unlocking unit is arranged on the wall, and the unlocking surface is configured to move radially along the output shaft to at least partially abut against the unlocking member; the wall is configured such that when the unlocking surface abuts against the unlocking member, the unlocking unit further moves radially along the output shaft and applies force to the unlocking member, enabling the wall to disengage the drive module from the output shaft; wherein a constant distance is maintained between the surface of the unlocking member that contacts the unlocking surface of the unlocking unit and the output shaft.

[0006] The unlockable inchworm-type rotary motor according to some embodiments of this specification includes an unlocking bearing, the unlocking bearing including an inner ring, an outer ring, and bearing balls disposed between the inner ring and the outer ring; wherein the inner ring is sleeved on the output shaft, and the outer ring forms the unlocking component.

[0007] According to some embodiments of this specification, the unlockable inchworm-type rotary motor is an unlocking member that is a fixedly arranged block structure; or, the unlocking member is at least a portion of a ring structure fixedly arranged around the output shaft.

[0008] According to some embodiments of this specification, the unlockable inchworm-type rotary motor is made of piezoelectric material and is configured such that, under the excitation of a first electrical signal, it is in the unlocked state and deforms in the radial direction of the output shaft, causing the unlocking surface to move toward the unlocking member.

[0009] According to some embodiments of this specification, the unlockable inchworm-type rotary motor is configured such that, without the first electrical signal excitation, it is disengaged from the unlocking member, or at a critical position about to contact the unlocking member, or at a position in contact with the unlocking member but without deforming the wall to the point that the drive module disengages from the output shaft.

[0010] According to some embodiments of this specification, the unlockable inchworm-type rotary motor includes two unlocking units, which are respectively located on both sides of the output shaft in a certain radial direction; or, the unlocking device includes more than two unlocking units, which are arranged around the output shaft in a circumferential direction.

[0011] According to some embodiments of this specification, the unlockable inchworm-type rotary motor includes a drive module comprising a first drive unit and a second drive unit disposed on the wall, the first drive unit and the second drive unit being made of piezoelectric material; the first drive unit and the second drive unit respectively include: a first module disposed on the wall and a second module disposed on the first module, the first module being configured to deform radially toward the center of the output shaft under the excitation of a second electrical signal, and the second module being configured to deform tangentially along the output shaft under the excitation of a third electrical signal; the first drive unit and the second drive unit are arranged in a direction parallel to the axial direction of the output shaft.

[0012] The unlockable inchworm-type rotary motor according to some embodiments of this specification includes a plurality of drive modules arranged around the output shaft, and each drive module is correspondingly provided with at least one unlocking unit.

[0013] According to some embodiments of this specification, each drive module is provided with one unlocking device, which is located between the first drive unit and the second drive unit of the drive module; or, each drive module is provided with two unlocking devices, which are located on both sides of the drive module along the axial direction of the output shaft.

[0014] According to some embodiments of this specification, the unlockable inchworm-type rotary motor includes: a first mounting portion for mounting the drive module; and a second mounting portion for mounting the unlocking device; wherein the first mounting portion has a first deformation portion on at least one side of its two sides along the axial direction of the output shaft, and the second mounting portion has a second deformation portion on at least one side of its two sides along the axial direction of the output shaft.

[0015] According to some embodiments of this specification, the unlockable inchworm-type rotary motor includes a first wall portion and a second wall portion, the thickness of the first wall portion being greater than the thickness of the second wall portion, and the second wall portion being capable of pivoting relative to the first wall portion about a pivot axis located in the radial plane of the output shaft in a direction toward or away from the output shaft; the first mounting portion and the second mounting portion are located in the first wall portion, and the first deformation portion and the second deformation portion are located in the second wall portion.

[0016] According to some embodiments of this specification, an unlockable inchworm-type rotary motor is provided with a groove in the second wall portion; or, a groove is provided between the first wall portion and the second wall portion; or, a portion of the first wall portion is provided with a groove to form the second wall portion; wherein the groove comprises: a first portion extending radially in the interior of the wall along the output shaft, and a second portion extending axially in the interior of the wall along the output shaft.

[0017] According to some embodiments of this specification, the unlockable inchworm-type rotary motor has the following features on its output shaft: an unlocking bearing shoulder, an unlocking bearing retaining ring groove, and an unlocking bearing retaining ring disposed within the unlocking bearing retaining ring groove; the unlocking bearing is disposed between the unlocking bearing shoulder and the unlocking bearing retaining ring; the unlocking bearing is configured to be fixed to the output shaft or to slide between the unlocking bearing shoulder and the unlocking bearing retaining ring along the axial direction of the output shaft.

[0018] The unlockable inchworm-type rotary motor according to some embodiments of this specification includes: a fixed guide bearing disposed at one end of the output shaft and a floating guide bearing disposed at the other end of the output shaft.

[0019] This specification provides one or more embodiments of an unlockable inchworm-type rotary motor, applicable to any of the unlockable inchworm-type rotary motors described above. The unlocking method includes: continuously applying a first electrical signal to the unlocking unit to cause the unlocking unit to extend, abut against the wall and the other of the unlocking components, and further extend to push the wall outward to cause the wall to disengage the drive module from the output shaft.

[0020] This specification provides one or more embodiments of an unlockable inchworm-type rotary motor, applicable to any of the unlockable inchworm-type rotary motors described above. The unlocking method includes: continuously applying a first electrical signal to the unlocking unit while the drive module is in a self-locked state, causing the unlocking unit to extend, abut against the wall and the other of the unlocking components, and further extend to push the wall outward and cause the wall to carry the drive module away from the output shaft.

[0021] The unlocking method according to some embodiments of this specification further includes: applying a fourth electrical signal to the plurality of drive modules to cause one or more of the plurality of drive modules to contract in the radial direction of the output shaft, so as to disengage one or more of the plurality of drive modules from the output shaft.

[0022] This specification provides one or more embodiments of a redundant drive mechanism, including: a power shaft and two or more unlockable inchworm-type rotary motors that are drively connected to the power shaft, wherein the unlockable inchworm-type rotary motors are the unlockable inchworm-type rotary motors described above.

[0023] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) unlocking the drive module of the inchworm-type rotary motor by disengaging it from the output shaft through the unlocking device; (2) the unlocking device is achieved by the cooperation of the unlocking unit and the unlocking component, and the unlocking component will not interfere with the free rotation of the output shaft; (3) the unlocking component adopts the unlocking bearing, and after unlocking, the output shaft only needs to overcome the rolling friction of the unlocking bearing, and the output shaft can rotate freely; (4) the unlocking unit adopts piezoelectric material, which is stretched or compressed under the action of electric field, with high speed, high energy efficiency and high positioning accuracy; (5) the deformation part formed by the thick wall part and the thin wall part makes the wall easy to deform, which is suitable for disengaging the drive module from the output shaft and meeting the unlocking requirements; (6) the rigidity of the wall is further adjusted by slotting, making the wall easy to deform, which is suitable for disengaging the drive module from the output shaft and meeting the unlocking requirements; (7) while applying an electrical signal excitation to the unlocking unit, an electrical signal excitation is also applied to the drive module to shorten the undamaged drive module and reduce the risk of "scratching".

[0024] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects may be any one or a combination of the above, or any other possible beneficial effects. Attached Figure Description

[0025] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. The same numbers in the drawings denote the same structures or steps.

[0026] Figure 1 is a schematic diagram of the inchworm-type rotary motor according to some embodiments of this specification.

[0027] Figure 2 is a schematic diagram of an unlockable inchworm-type rotary motor according to some embodiments of this specification.

[0028] Figure 3 is a cross-sectional schematic diagram of an unlockable inchworm-type rotary motor according to some embodiments of this specification, which shows the unlocking device of some embodiments.

[0029] Figure 4 is a magnified view of the middle part of Figure 3.

[0030] Figure 5 is a cross-sectional schematic diagram of an unlockable inchworm-type rotary motor according to some embodiments of this specification, showing the drive module, guide bearing, and related wall structures of some embodiments.

[0031] Figure 6 is a magnified view of the upper part of Figure 5.

[0032] Figure 7 is a magnified view of the middle part of Figure 5.

[0033] Figure 8 is a magnified view of the lower part of Figure 5.

[0034] Figure 9 is a schematic diagram of a block-structured unlocking component of an unlockable inchworm-type rotary electric motor according to some embodiments of this specification.

[0035] Figure 10 is a schematic diagram of an unlockable inchworm-type rotary motor, including an unlocking unit, a first drive unit, and a second drive unit, according to some embodiments of this specification.

[0036] Figure 11 is a schematic diagram showing the deformation direction of the unlocking unit, the first drive unit, and the second drive unit of an unlockable inchworm-type rotary motor according to some embodiments of this specification.

[0037] Figure 12 is a schematic diagram of a piezoelectric ceramic stack with d33 parameter directional polarization of an unlockable inchworm-type rotary motor according to some embodiments of this specification.

[0038] Figure 13 is a schematic diagram of a piezoelectric ceramic stack with d15 parameter directional polarization of an unlockable inchworm-type rotary motor according to some embodiments of this specification.

[0039] The diagram shows the following markings: 100 First piezoelectric drive unit; 200 Second piezoelectric drive unit; 101 Forward module; 102 Tangential module; 1 Wall; 11 First mounting part; 12 Second mounting part; 13 First deformation part; 14 Second deformation part; 15 Groove; 2 Output shaft; 21 Unlock bearing shoulder; 22 Unlock bearing retaining ring groove; 23 Unlock bearing retaining ring; 24 Fixed guide bearing shoulder; 25 Floating guide bearing shoulder; 26 Floating guide bearing retaining ring; 3 Drive module; 31 First drive unit; 32 Second drive unit; 301 First module; 302 Second module; 4 Unlocking device; 41 Unlock bearing; 411 Inner ring; 412 Outer ring; 413 Bearing ball; 42 Unlocking unit; a Left side wall; b Right side wall; c Upper end plate; c1 Fixed guide bearing boss; d Lower end plate; d1 Floating guide bearing boss; 51 Fixed guide bearing; 52 Floating guide bearing; 6 Locking nut. Detailed Implementation

[0040] To more clearly illustrate the technical solutions of the embodiments in this specification, the embodiments will be described in detail below with reference to the accompanying drawings. Obviously, the content described below are some examples or embodiments of this specification. For those skilled in the art, without creative effort, the technical solutions or means disclosed in this specification can be applied to other scenarios based on this technical content.

[0041] Unless otherwise specified, the technical terms used to describe components, elements, etc. in this specification are not singular but may include plural. Generally speaking, terms such as "comprising" or "including" only indicate that explicitly identified steps, elements, or components are included, and these steps, elements, and components do not constitute an exclusive list, as the described method or apparatus may also include other steps or components.

[0042] With the continuous development of precision motion technology, especially in fields such as semiconductors, optics, and aerospace where equipment is used in vacuum environments, the requirements for the size, precision, and ultimate vacuum level of end effectors in these devices are becoming increasingly stringent. Among these, regarding size, high vacuum (e.g., 10⁻⁶) is particularly crucial. -1 Pa~10 -5 Pa) and ultra-high vacuum (e.g., 10 ... -5 Pa~10 -8 Setting up and maintaining a vacuum environment (e.g., vacuum level) is extremely difficult, and the difficulty increases exponentially with the increase in cavity volume. Therefore, the smaller the internal structure of the cavity, the better, as this allows for a reduction in cavity size and facilitates the achievement of higher vacuum levels. Regarding precision, in some precision motion fields such as optics and semiconductors, artificially creating a vacuum is to obtain higher accuracy for end effectors. The fundamental reason is that temperature changes in the atmospheric environment, heat generated by the end effector itself during operation, airflow, and light can all cause inaccuracies in the end effector's movement.

[0043] Therefore, piezoelectric actuators, which utilize the inverse piezoelectric effect to generate power, have emerged. Piezoelectric actuators mainly include piezoelectric motors. Piezoelectric motors include linear motors and rotary motors. For example, the driving method of a piezoelectric rotary motor, such as an inchworm-type piezoelectric rotary motor, is mainly achieved by at least two sets of internal drive units, such as piezoelectric ceramic drive units, performing a "clamp-drive-release" action on the output shaft. Furthermore, during the manufacturing of this type of motor, it is necessary to ensure that a certain preload is applied to the internal piezoelectric ceramic drive units. Therefore, when the inchworm-type piezoelectric rotary motor is not powered on, the drive units are in a clamped state on the output shaft, causing the output shaft of the inchworm-type piezoelectric rotary motor to self-lock.

[0044] In some embodiments, referring to FIG1, the inchworm-type piezoelectric rotary motor includes a first piezoelectric drive unit 100 and a second piezoelectric drive unit 200. In some embodiments, the first piezoelectric drive unit 100 and the second piezoelectric drive unit 200 are piezoelectric ceramic drive units. In some embodiments, both the first piezoelectric drive unit 100 and the second piezoelectric drive unit 200 include a forward module 101 and a tangential module 102. The forward module 101 undergoes forward deformation under voltage excitation, that is, deformation along the radial direction of the output shaft; the tangential module 102 undergoes tangential deformation under voltage excitation, that is, deformation along the tangential direction of the outer edge of the output shaft.

[0045] Referring to Figure 1, which illustrates the working principle of the inchworm-type piezoelectric rotary motor in some embodiments, the forward module 101 deforms in the direction from the upper left to the lower right under voltage excitation, for example, elongating or shortening. In some embodiments, it remains a rectangular body after deformation. The tangential module 102 deforms in the direction from the lower left to the upper right under voltage excitation, for example, the right end faces to the lower left or to the upper left. In some embodiments, it transforms from a rectangular body into a parallelogram.

[0046] Referring again to Figure 1, in some embodiments, the working principle of the inchworm-type piezoelectric rotary motor includes the following steps.

[0047] S100: The forward module 101 and tangential module 102 of the first piezoelectric drive unit 100 and the second piezoelectric drive unit 200 are in an initial state without electrical signal excitation; a fifth electrical signal excitation is applied to the forward module 101 of the first piezoelectric drive unit 100, and a sixth electrical signal excitation is applied to the forward module 101 of the second piezoelectric drive unit 200. The fifth and sixth electrical signals can be in phase, have the same frequency, and be in opposite directions, causing the forward module 101 of the first piezoelectric drive unit 100 to extend in the radial direction and causing the tangential module 102 of the first piezoelectric drive unit 100 to abut against the output shaft; causing the forward module 101 of the second piezoelectric drive unit 200 to shorten in the radial direction and causing the tangential module 102 of the second piezoelectric drive unit 200 to disengage from the output shaft.

[0048] S200: The forward module 101 of the first piezoelectric drive unit 100 and the forward module 101 of the second piezoelectric drive unit 200 are held together. A seventh electrical signal is applied to the tangential module 102 of the first piezoelectric drive unit 100, and an eighth electrical signal is applied to the tangential module 102 of the second piezoelectric drive unit 200. The seventh and eighth electrical signals can be in phase, have the same frequency, and be in opposite directions, causing the tangential module 102 of the first piezoelectric drive unit 100 to extend along the tangential direction of the first direction (e.g., clockwise around the output shaft), and under the action of friction, "rub" the output shaft to generate clockwise rotation; causing the tangential module 102 of the second piezoelectric drive unit 200 to extend along the tangential direction of the second direction (e.g., counterclockwise around the output shaft), preparing for the next step of inchworm movement.

[0049] S300: The tangential module 102 of the first piezoelectric drive unit 100 and the tangential module 102 of the second piezoelectric drive unit 200 are held together. A ninth electrical signal is applied to the forward module 101 of the first piezoelectric drive unit 100, and a tenth electrical signal is applied to the forward module 101 of the second piezoelectric drive unit 200. The ninth electrical signal can be in phase, have the same frequency, and be in the opposite direction to the fifth electrical signal in S100, and the tenth electrical signal can be in phase, have the same frequency, and be in the opposite direction to the sixth electrical signal in S100. This causes the forward module 101 of the first piezoelectric drive unit 100 to shorten in the radial direction and causes the tangential module 102 of the first piezoelectric drive unit 100 to disengage from the output shaft; and causes the forward module 101 of the second piezoelectric drive unit 200 to lengthen in the radial direction and causes the tangential module 102 of the second piezoelectric drive unit 200 to abut against the output shaft.

[0050] S400: The forward module 101 of the first piezoelectric drive unit 100 and the forward module 101 of the second piezoelectric drive unit 200 are maintained. An eleventh electrical signal is applied to the tangential module 102 of the first piezoelectric drive unit 100, and a twelfth electrical signal is applied to the tangential module 102 of the second piezoelectric drive unit 200. The eleventh electrical signal can be in phase, have the same frequency, and be in the opposite direction to the twelfth electrical signal. Specifically, the eleventh electrical signal can be in phase, have the same frequency, and be in the opposite direction to the seventh electrical signal in S200, and the twelfth electrical signal can be in phase, have the same frequency, and be in the opposite direction to the eighth electrical signal in S200. This causes the tangential module 102 of the first piezoelectric drive unit 100 to extend along the tangential direction of the second direction (e.g., counterclockwise around the output shaft), preparing for the next step of the inchworm movement. The tangential module 102 of the second piezoelectric drive unit 200 extends along the tangential direction of the first direction (e.g., clockwise around the output shaft), and under the action of friction, "rubs" the output shaft to generate clockwise rotation.

[0051] S500: The tangential module 102 of the first piezoelectric drive unit 100 and the tangential module 102 of the second piezoelectric drive unit 200 are held together. A fifth electrical signal excitation is applied to the forward module 101 of the first piezoelectric drive unit 100, and a sixth electrical signal excitation is applied to the forward module 101 of the second piezoelectric drive unit 200, causing the forward module 101 of the first piezoelectric drive unit 100 to extend in the radial direction and causing the tangential module 102 of the first piezoelectric drive unit 100 to abut against the output shaft; the forward module 101 of the second piezoelectric drive unit 200 to shorten in the radial direction and causing the tangential module 102 of the second piezoelectric drive unit 200 to disengage from the output shaft.

[0052] The output shaft can be continuously rotated along a first direction, such as clockwise, by cycling from S200 to S500, thus achieving inchworm-like 360° rotation of the piezoelectric rotary motor.

[0053] In some embodiments, the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth electrical signals described above may be voltage signals or current signals.

[0054] In some embodiments, the working principle of the inchworm-type piezoelectric rotary motor is mainly achieved by adjusting whether the two tangential modules provide force to the output shaft through the forward module, and then rotating the output shaft by the tangential force provided by the tangential module in the tangential direction. The force in the tangential direction is a frictional force, such as static friction. In some embodiments, during the manufacturing of the inchworm-type piezoelectric rotary motor, it is necessary to ensure that a certain preload is applied to its internal piezoelectric drive unit, such as the first piezoelectric drive unit 100 or the second piezoelectric drive unit 200. Therefore, when the inchworm-type piezoelectric rotary motor is not powered on, the piezoelectric drive unit is in a clamped state relative to the output shaft, resulting in the output shaft of the inchworm-type piezoelectric rotary motor being self-locked (i.e., having a self-locking force). The static friction force applied to the output shaft by the piezoelectric drive unit in the positive direction, i.e., the radial direction of the output shaft, is often greater than the static friction force applied to the output shaft in the tangential direction by the deformation generated after the piezoelectric drive unit is powered on (which is also the driving force driving the output shaft to rotate). Therefore, when one piezoelectric drive unit is damaged and continuously applies static friction force to the output shaft in the positive direction, the driving force applied to the output shaft in the tangential direction by the other piezoelectric drive unit cannot take effect, and the output shaft cannot rotate. Therefore, the inchworm-type piezoelectric rotary motor is self-locking in the state of being unpowered or damaged; in other words, it has a self-locking characteristic.

[0055] In some embodiments, such as applications requiring a vacuum environment, motor failure would render the entire device inoperable, and replacing the motor would drastically increase costs by disrupting the vacuum environment. In other embodiments, such as in the aerospace field, motor failure makes it impossible to promptly access the interior of a flying aircraft or the equipment in space for maintenance due to limited resources. Therefore, as an alternative solution, redundant drive mechanisms can be implemented. In some embodiments, a redundant drive mechanism refers to two or more motors connected to the same drive shaft via a transmission structure, allowing the two or more motors to drive the drive shaft independently. For example, under normal conditions, the drive shaft is driven by one rotary motor; if this rotary motor fails, another redundant rotary motor is activated to drive the drive shaft.

[0056] Therefore, the prerequisite for arranging a redundant drive mechanism is that the two motors cannot interfere with each other. In other words, if either motor fails, the output shaft connected to the drive shaft should be open, not locked. However, as mentioned above, the inchworm-type piezoelectric rotary motor has a self-locking characteristic, making it impossible to arrange a redundant drive mechanism. Specifically, if a redundant inchworm-type piezoelectric rotary motor is arranged, it needs to overcome the self-locking of the damaged inchworm-type piezoelectric rotary motor. However, as explained above, the driving force of the inchworm-type piezoelectric rotary motor is likely less than its self-locking force. Therefore, the redundant inchworm-type piezoelectric rotary motor may not be able to overcome the self-locking of the damaged inchworm-type piezoelectric rotary motor, and its redundancy function cannot be realized.

[0057] Existing conventional rotary motors, which convert electrical energy into mechanical energy using brushes and commutators, are relatively large and unsuitable for use in confined spaces. Inchworm-type piezoelectric rotary motors, due to their smaller size and structural characteristics, can better address the space issue. However, existing inchworm-type piezoelectric rotary motors have a self-locking characteristic, making it impossible to arrange redundant drive mechanisms like the aforementioned conventional rotary motors. Therefore, there is an urgent need to design an inchworm-type piezoelectric rotary motor that can unlock from its self-locking state without disrupting the vacuum environment on Earth or requiring operators to enter space.

[0058] Figure 2 is a schematic diagram of an unlockable inchworm-type rotary motor according to some embodiments of this specification, and Figure 3 is a cross-sectional schematic diagram of an unlockable inchworm-type rotary motor according to some embodiments of this specification. As shown in Figures 2 and 3, some embodiments of this specification provide an unlockable inchworm-type rotary motor, such as an unlockable inchworm-type piezoelectric rotary motor. Although the embodiments of this specification mainly use an unlockable inchworm-type piezoelectric rotary motor as an example, the unlocking device used to achieve unlocking can also be applied to inchworm-type rotary motors other than inchworm-type piezoelectric rotary motors, and non-inchworm-type piezoelectric rotary motors.

[0059] In some embodiments, the unlockable inchworm-type piezoelectric rotary motor includes: a wall 1, a rotatable output shaft 2, a drive module 3 directly or indirectly disposed on the wall 1 to drive the output shaft 2 to rotate, and an unlocking device 4 for disengaging the drive module 3 from the output shaft 2 in the unlocked state.

[0060] The unlocking device 4 includes: a fixedly disposed unlocking member and an unlocking unit 42 disposed directly or indirectly on one of the wall 1 and the unlocking member. A gap exists between the unlocking member and the output shaft 2. The unlocking unit 42 has an unlocking surface configured to move radially along the output shaft 2 to at least partially abut against the other of the wall 1 and the unlocking member. In some embodiments, the unlocking surface may be an end face or a portion of the end face of the unlocking unit 42. In other embodiments, the unlocking surface may be a side surface of an end of the unlocking unit 42. In some embodiments, the unlocking surface may be a plane or an arc surface. The specific shape of the unlocking unit 42 and the specific shape of the unlocking surface can be selected according to actual needs, such that the unlocking surface can abut against the other of the wall 1 and the unlocking member, and is suitable for applying force to the other of the wall 1 and the unlocking member.

[0061] Wall 1 is configured such that when the unlocking surface of unlocking unit 42 abuts against the other of wall 1 and unlocking member, further radial movement of unlocking unit 42 along output shaft 2 and application of force to the other of wall 1 and unlocking member can disengage wall 1 carrying drive module 3 from output shaft 2 (e.g., by the reaction force received by unlocking unit 42). Exemplarily, unlocking unit 42 further applies force to the other of wall 1 and unlocking member, increasing the distance between wall 1 and output shaft 2, thereby disengaging drive module 3 on wall 1 from output shaft 2. In some embodiments, movement of unlocking unit 42 refers to elongation or shortening due to deformation. In other embodiments, movement of unlocking unit 42 may also refer to translation of its entirety.

[0062] In some embodiments, the two ends of the unlocking unit 42 abut against the wall 1 and the unlocking member, respectively. The unlocking member is fixedly disposed, its position relative to the output shaft 2 is fixed, and it does not interfere with the free rotation of the output shaft 2. Exemplarily, in some embodiments, the unlocking member can be positioned on the output shaft 2 and rotatably connected to it, maintaining a constant distance between the surface of the unlocking member and the unlocking surface of the unlocking unit 42 and the output shaft 2, without affecting the rotation of the output shaft 2. Exemplarily, in other embodiments, the unlocking member can also be fixed to the housing, for example, to the upper or lower end plate of the housing. Since the position of the output shaft 2 inside the housing is fixed, the position of the unlocking member inside the housing is also fixed, maintaining a constant distance between the surface of the unlocking member and the unlocking surface of the unlocking unit 42 and the output shaft 2, while there is no contact between the unlocking member and the output shaft 2, thus not affecting the rotation of the output shaft 2.

[0063] By arranging the aforementioned unlocking device 4, the inchworm-type piezoelectric rotary motor in some embodiments can enter the unlocked state by unlocking the device 4 according to actual needs (e.g., when damaged or the drive module 3 cannot detach from the output shaft 2). This allows the inchworm-type piezoelectric rotary motor to be equipped with a redundant mechanism, so that the redundant inchworm-type piezoelectric rotary motor can drive the power shaft without being affected by the damaged inchworm-type piezoelectric rotary motor, further improving system reliability and reducing maintenance costs.

[0064] In some embodiments, the unlocking unit 42 extends due to deformation, moving the wall 1 away from the unlocking member, thereby moving the wall 1 away from the output shaft 2. In some embodiments, the unlocking unit 42 may be fixed to the wall 1 and apply force to the unlocking member, or it may be fixed to the unlocking member and apply force to the wall 1.

[0065] Referring to Figures 3 and 4, in some embodiments, the unlockable inchworm-type piezoelectric rotary motor includes an unlocking bearing 41. The unlocking bearing 41 includes an inner ring 411, an outer ring 412, and bearing balls 413 located between the inner ring 411 and the outer ring 412. The inner ring 411 of the unlocking bearing 41 is connected to the output shaft 2, and the outer ring 412 of the unlocking bearing 41 forms the aforementioned unlocking member. The outer ring 412 of the unlocking bearing 41 mates with the unlocking surface of the unlocking unit 42. In some embodiments, the unlocking surface of the unlocking unit 42 can completely abut against the outer ring 412 of the unlocking bearing 41; in other embodiments, the unlocking surface of the unlocking unit 42 can partially abut against the outer ring 412 of the unlocking bearing 41. In some embodiments, the unlocking bearing 41 is a deep groove ball bearing.

[0066] To install the unlocking bearing 41, as shown in Figure 4, in some embodiments, the output shaft 2 includes: an unlocking bearing shoulder 21, an unlocking bearing retaining ring groove 22, and an unlocking bearing retaining ring 23 disposed within the unlocking bearing retaining ring groove 22. The unlocking bearing 41 is located between the unlocking bearing shoulder 21 and the unlocking bearing retaining ring 23.

[0067] The unlocking bearing shoulder 21 is a stepped structure on the output shaft 2. The output shaft 2 forms this stepped structure by changing its outer diameter, which limits the unlocking bearing 41 in one axial direction. In some embodiments, the unlocking bearing retaining ring groove 22 is formed radially on the surface of the output shaft 2. The inner diameter of the unlocking bearing retaining ring 23 is smaller than the outer diameter of the output shaft 2. When the unlocking bearing retaining ring 23 is installed in the unlocking bearing retaining ring groove 22, it limits the unlocking bearing 41 in another axial direction of the output shaft 2. In some specific embodiments, the unlocking bearing retaining ring 23 is deformed and fitted onto the output shaft 2. After passing through the unlocking bearing retaining ring groove 22, it recovers its shape and falls into the unlocking bearing retaining ring groove 22. In some specific embodiments, the unlocking bearing 41 is fitted onto the output shaft 2, making it contact the unlocking bearing shoulder 21, and then the unlocking bearing retaining ring 23 is installed.

[0068] In some embodiments, the unlocking bearing 41 is configured to slide between the unlocking bearing shoulder 41 and the unlocking bearing retaining ring 23 along the axial direction of the output shaft 2. The unlocking bearing 41 does not guide or limit the axial position of the output shaft 2, and does not require precise positioning or fixation; it only needs to allow smooth rolling, thus allowing it to slide within a certain range.

[0069] In other embodiments, the unlocking bearing 41 is configured to be fixed to the output shaft 2. Exemplarily, the unlocking bearing 41 is fixed to the output shaft 2 with an interference fit.

[0070] In one or more embodiments of this specification, when the unlocking surface of the unlocking unit 42 abuts against the outer ring of the unlocking bearing 41, the unlocking unit 42 further moves radially along the output shaft 2 and applies force to the wall 1 to disengage the drive module 3 from the output shaft 2. The wall 1 is configured to be able to disengage the drive module 3 from the output shaft 2 by the force provided by the unlocking unit 42; for example, a portion of the wall 1 is configured to be able to displace away from the output shaft 2, or it is configured to expand away from the output shaft 2 through deformation, thereby disengaging the drive module 3 from the output shaft 2.

[0071] In some embodiments, the unlocking unit 42 is made of a piezoelectric material, such as a piezoelectric ceramic material. The unlocking unit 42 is configured such that, under the first electrical signal excitation, such as a first voltage excitation, it is in an unlocked state and deforms in the radial direction of the output shaft 2, causing the unlocking surface to move toward the outer ring 412 of the unlocking member, such as the unlocking bearing 41. Without the first electrical signal excitation, such as the first voltage excitation, it is disengaged from the unlocking member, such as the unlocking bearing 41, or is at a critical position about to contact the unlocking member, such as the unlocking bearing 41, or is in contact with the unlocking member, such as the unlocking bearing 41, but does not deform the wall 1 to the point that the drive module 3 disengages from the output shaft 2. It should be noted that "without the first electrical signal excitation" can specifically mean not applying any electrical signal, or applying an electrical signal different from the first electrical signal, such as an electrical signal in the opposite direction to the first electrical signal.

[0072] Specifically, the unlocking unit 42 deforms through electrical signal excitation, such as voltage excitation, extending its length in the radial direction of the output shaft 2, and for example, extending its length in the horizontal direction as shown in Figures 3 and 4, to increase the distance between the unlocking bearing 41 and the wall 1. Since the unlocking bearing 41 is rigid and its stiffness is configured to be greater than that of the wall 1, the wall 1 is expanded / pushed away from the output shaft 2 relative to the unlocking bearing 41, and the drive module 3 mounted on the wall 1 is also pushed away from the output shaft 2, thereby disengaging the drive module 3 from the output shaft 2 and releasing the motor from its self-locking state. On the other hand, due to the arrangement of the unlocking bearing 41, the large static friction force exerted by the unlocking unit 42 on the output shaft 2 is transformed into a smaller rolling friction force on the unlocking bearing 41, ensuring that the extension of the unlocking unit 42 does not affect the rotation of the output shaft 2.

[0073] In other words, by cooperating with the unlocking bearing 41 and the unlocking unit 42, the static friction force between the drive module 3 and the output shaft 2 that the redundant motor originally needed to overcome is transformed into the rolling friction force that needs to be overcome by the unlocking bearing 41. The value of the rolling friction force is several orders of magnitude smaller than the value of the static friction force, so unlocking can be achieved in the event of damage or failure of the drive module 3.

[0074] In some embodiments, the unlocking unit 42 employs high-voltage piezoelectric ceramics, such as lead zirconate titanate-based piezoelectric ceramics. In some embodiments, the drive module 3 may include the aforementioned first piezoelectric drive unit 100 and the aforementioned second piezoelectric drive unit 200. Compared to the low-voltage piezoelectric ceramics, such as barium titanate-based piezoelectric ceramics, used in some embodiments of the drive module 3, the high-voltage piezoelectric ceramics used in the unlocking unit 42, under the premise of the same polarization direction and the same size, can generate greater output force and elongation displacement by applying high-voltage excitation.

[0075] In some embodiments, the unlocking unit 42 is a piezoelectric ceramic stack, such as a high-voltage piezoelectric ceramic stack. Exemplarily, the unlocking unit 42 includes multiple piezoelectric sheets bonded together with an adhesive, or bonded together in a molten state to form the aforementioned stack. In some embodiments, the unlocking unit 42 is a piezoelectric ceramic stack polarized using the d33 parameter direction. In some embodiments, the unlocking unit 42 is fixedly connected to the wall 1 by adhesive bonding. For example, please refer to FIG12, which illustrates a piezoelectric ceramic stack polarized using the d33 parameter direction. After polarizing the piezoelectric ceramic stack along the positive z-axis direction (polarization direction P) in FIG12, when an external electric field E is applied along the positive z-axis direction in FIG12, the piezoelectric ceramic can deform along the z-axis. This mode, where the electric field direction and the vibration direction are parallel, is called a longitudinal vibration mode (i.e., the d33 mode).

[0076] In the initial state, the unlocking unit 42, such as the high-voltage piezoelectric ceramic unlocking unit, and the outer ring 412 of the unlocking bearing 41 are in a critical state between contact and non-contact, or there is only a very small interaction force between them, so as not to affect the operation of the drive module 3.

[0077] In one or more embodiments of this specification, referring to Figures 3 and 4, the unlocking device 4 includes two unlocking units 42, which are respectively disposed on both sides of the output shaft 2 in a certain radial direction. In other embodiments, the unlocking device includes two or more unlocking units, which are arranged radially around the output shaft. For example, the unlocking device includes three unlocking units, which are arranged at 120° around the output shaft. For example, the unlocking device includes four unlocking units, which are arranged at 90° around the output shaft.

[0078] Referring to Figures 5, 10, and 11, in one or more embodiments of this specification, the drive module 3 includes a first drive unit 31 and a second drive unit 32 disposed on the wall 1. The first drive unit 31 and the second drive unit 32 respectively include a first module 301 disposed on the wall 1 and a second module 302 disposed on the first module 301. The first module 301 deforms radially toward the center of the output shaft 2 under the excitation of a second electrical signal, such as a second voltage excitation. The second module 302 deforms tangentially along the output shaft 2 under the excitation of a third electrical signal, such as a third voltage excitation. Exemplarily, the second electrical signal may be similar to the aforementioned fifth or tenth electrical signal, and is used to elongate the first module 301. Exemplarily, the second electrical signal may also be similar to the aforementioned sixth or ninth electrical signal, and is used to shorten the first module 301. For example, the third electrical signal may be similar to the aforementioned seventh, eighth, eleventh, and twelfth signals, and the third signal is used to cause the second module 302 to extend in a tangential direction in a clockwise or counterclockwise direction around the output shaft.

[0079] The first drive unit 31 and the second drive unit 32 are similar to the aforementioned first piezoelectric drive unit 100 and second piezoelectric drive unit 200, and the first module 301 and the second module 302 are similar to the aforementioned forward module 101 and tangential module 102. The working principle of the drive module 3 is also similar to the aforementioned steps S100 to S500, so it will not be described again.

[0080] In some embodiments, the first module 301 is a piezoelectric ceramic stack polarized with a d33 parameter direction, commonly known as a "positive plate," which provides a clamping action to move toward the center of the output shaft 2 under electrical signal excitation, such as voltage excitation; the second module 302 is a piezoelectric ceramic stack polarized with a d15 parameter direction, commonly known as a "tangential plate," which provides an actuating action to move tangentially along the outer edge of the output shaft 2 under electrical signal excitation, such as voltage excitation. For example, please refer to Figure 13, which illustrates a piezoelectric ceramic stack polarized with a d15 parameter direction. After polarizing the piezoelectric ceramic stack along the positive z-axis (polarization direction P) in Figure 13, when an external electric field E is applied along the positive x-axis in Figure 13, the piezoelectric ceramic undergoes shear deformation around the y-axis. This mode, in which the electric field direction, polarization direction, and the direction of the piezoelectric ceramic stack deformation are mutually perpendicular, is called a torsional vibration mode (i.e., the d15 mode).

[0081] In some embodiments, the first module 301 and the second module 302 employ a piezoelectric ceramic stack, such as a low-voltage piezoelectric ceramic stack. Exemplarily, the first module 301 and the second module 302 include multiple piezoelectric sheets, which are bonded together by an adhesive or bonded together in a molten state to form the aforementioned stack. In some embodiments, the first module 301 and the second module 302 are fixedly connected to the wall 1 by adhesive bonding.

[0082] For the first module 301 and the second module 302, there are gaps of varying widths between the piezoelectric sheets. When the piezoelectric sheets deform, these gaps consume some of the deformation. In other words, the deformation of the piezoelectric sheets first fills these gaps before the piezoelectric ceramic stack exhibits elongation or shortening deformation. Therefore, in some embodiments, a certain pre-pressure is provided to the piezoelectric ceramic stack through the wall 1. This pre-pressure can significantly reduce the gaps between the piezoelectric sheets, improve deformation efficiency, and significantly enhance the performance and lifespan.

[0083] In some embodiments, the straight line containing the first drive unit 31 and the second drive unit 32 of the same drive module 3 is arranged parallel to the output shaft 2. For example, the first module 301 of the first drive unit 31 and the first module 301 of the second drive unit 32 of one drive module 3 are arranged along a first straight line, which is parallel to the axial direction of the output shaft 2 or parallel to a generatrix of the output shaft 2. For example, the first module 301 of the first drive unit 31 and the first module 301 of the second drive unit 32 of another drive module 3 are arranged along a second straight line, which is parallel to the axial direction of the output shaft 2 or parallel to another generatrix of the output shaft 2.

[0084] In one or more embodiments of this specification, a plurality of drive modules 3 are arranged around an output shaft 2, and each drive module 3 is provided with at least one unlocking unit 42. For example, referring to Figures 3 and 5, two drive modules 3 are included, located on opposite sides of the output shaft 2, and each drive module 3 is provided with at least one unlocking unit 42. Again referring to Figures 3 and 5, for example, each drive module 3 has an unlocking device 4 on its upper and lower sides, and each unlocking device 4 has an unlocking unit 42 on each of the left and right sides of the output shaft, meaning that each side of the drive module 3 has two unlocking units 42 on its upper and lower sides respectively.

[0085] In other embodiments, each drive module is provided with an unlocking device located between the first drive unit and the second drive unit of the drive module. In other words, the first drive unit and the second drive unit of the drive module are located on both sides of the unlocking device in the axial direction.

[0086] The location and number of unlocking devices can be selected according to actual needs, so that they can disengage all drive modules from the output shaft after electrical signal excitation, such as voltage excitation.

[0087] Referring to Figure 7, in one or more embodiments of this specification, the wall 1 includes: a first mounting portion 11 for mounting the drive module 3 and a second mounting portion 12 for mounting the unlocking device 4. The first mounting portion 11 has a first deformation portion 13 on at least one side of its two sides along the axial direction of the output shaft 2, and the second mounting portion 12 has a second deformation portion 14 on at least one side of its two sides along the axial direction of the output shaft 2.

[0088] In some embodiments, the inchworm-type piezoelectric rotary motor includes a rotor and a stator, wherein the rotor is an output shaft 2 and the stator, for example, is provided with a wall 1 by a stator housing.

[0089] In some embodiments, the first deformation portion 13 and the second deformation portion 14 are used to provide deformation, enabling the wall 1 to carry the drive module 3 away from the output shaft 2. In some embodiments, the wall 1 is formed of a flexible material or a partially flexible material to form the first deformation portion 11 and / or the second deformation portion 12. In other embodiments, the wall 1 is formed of a flexible structure, such as a flexible hinge structure, to form the first deformation portion 11 and / or the second deformation portion 12. A flexible hinge structure refers to a structure arranged on the wall 1 that, despite being made of a rigid material such as metal or alloy, still possesses a certain degree of flexibility and allows for a certain degree of deformation. Specifically, the flexible hinge structure is similar to a hinge structure, which allows a portion of the wall 1 to pivot to a certain extent relative to another portion of the wall 1.

[0090] For example, wall 1 includes a first wall portion and a second wall portion. The thickness of the first wall portion is greater than the thickness of the second wall portion. The second wall portion is pivotable relative to the first wall portion about a pivot axis located in the radial plane of the output shaft 2. For example, it can pivot towards or away from the output shaft 2. In some embodiments, the pivot axis is located in the plane of wall 1, in which case the pivoting of the second wall portion relative to the first wall portion is a rotation as a whole. In other embodiments, there may be an angle between the pivot axis and the plane of wall 1, in which case the pivoting of the second wall portion relative to the first wall portion may include both rotation and torsion. The first mounting portion 11 and the second mounting portion 12 are located in the first wall portion, and the first deformable portion 13 and the second deformable portion 14 are located in the second wall portion. Specifically, since wall 1 has a thickness variation, its thinner portion is more prone to deformation than its thicker portion, that is, the second wall portion is more likely to pivot relative to the first wall portion, forming the aforementioned flexible hinge structure. It should be noted that the above pivoting is intended to clarify the possible kinematic or deformation relationship between the first wall portion and the second wall portion. In some embodiments, there is no actual physical pivot axis. In some embodiments, the pivoting between the first wall portion and the second wall portion cannot be accurately simulated at the microscopic level as pivoting around a pivot axis. Specifically, the macroscopic pivoting motion between the first wall portion and the second wall portion can be achieved by microscopic irregular deformation.

[0091] Referring to Figure 7, the wall thickness of the first mounting portion 11 is greater than the wall thickness of the portions on both sides of the first mounting portion 11 (e.g., at the first deformable portion 13). The wall thickness of the second mounting portion 12 is greater than the wall thickness of the portions on both sides of the second mounting portion 12 (e.g., at the first deformable portion 13 or the second deformable portion 14). Furthermore, it can also be seen in Figure 7 that the wall thickness of the first mounting portion 11 is greater than the wall thickness of the second mounting portion 12, so as to facilitate pivoting between the second mounting portion 12 and the first mounting portion 11.

[0092] In some embodiments, a first deformation portion 13 is provided on each side of the first mounting portion 11, and a second deformation portion 14 is provided on each side of the second mounting portion 12. In other embodiments, a first deformation portion 13 is provided on each side of the first mounting portion 11, a second deformation portion 14 is provided on one side of the second mounting portion 12, and the other side of the second mounting portion 12 shares the first deformation portion 13 with the first mounting portion 11.

[0093] For example, continuing to refer to Figures 3 and 7, the unlocking unit 42, under electrical signal excitation such as voltage excitation, causes the second mounting part 12 to shift to the left side in Figure 7. The first deformation part 13 on one side of the second mounting part 12 undergoes a certain deformation to pull the first mounting part 11 to the left side in Figure 7. Furthermore, the pivoting of the second deformation part 14 drives the second mounting part 12 and the first mounting part 11 to shift to the left side in Figure 7 as a whole, thereby causing the drive module 3 to disengage from the output shaft 2 and achieve unlocking.

[0094] In one or more embodiments of this specification, a groove 15 is provided at the second wall portion, for example, a groove 15 is provided on one side of the second wall portion. For example, referring to FIG7, a groove 15 is provided at the upper side of the second deformation portion 14 of the upper second mounting portion 12, and a groove 15 is also provided at the lower side of the second deformation portion 14 of the lower second mounting portion 12. The groove 15 further reduces the stiffness of one side of the second wall portion, making it easier to deform and displace in response to the force provided by the unlocking unit 42.

[0095] In some embodiments, a groove 15 is formed between the first wall portion and the second wall portion. For example, grooves 15 are formed on the upper and lower sides of the first mounting portion 11. The groove 15 further reduces the stiffness at the connection between the first wall portion and the second wall portion, making it easier for it to deform and displace in response to the force provided by the unlocking unit 42.

[0096] In other embodiments, the wall 1 is planar in its unprocessed state, and a thinner second wall is formed by creating a groove 15 in a portion of the thicker first wall portion (e.g., the upper or lower end of the first wall portion).

[0097] Specifically, in some embodiments, the stiffness of the wall 1 is reduced by varying its thickness, making it easier to deform and displace. In other embodiments, its stiffness is reduced by creating grooves in the wall 1, making it easier to deform and displace. In still other embodiments, the wall 1 has both varying thicknesses and grooves.

[0098] In one or more embodiments of this specification, referring to FIG7, the groove 15 includes: a first portion (e.g., a horizontal portion in FIG7) extending radially along the output shaft 2 inside the wall 1, and a second portion (e.g., a vertical portion in FIG7) extending axially along the output shaft 2 inside the wall 1, the first and second portions providing space for deformation. In some embodiments, the groove 15 is L-shaped or T-shaped. Exemplarily, as previously described, in some embodiments, the wall 1 provides a preload to the first drive unit 31 and the second drive unit 32, under which the first mounting portion 11, on which the first drive unit 31 and the second drive unit 32 are mounted, protrudes outward relative to other portions of the wall 1, for example, protruding to the left in FIG7, and the first and second portions of the groove 15 provide space for such deformation. On the other hand, the first and second portions of the groove 15 also provide space for the deformation of the wall 1 caused by the force exerted on the wall 1 by the unlocking unit 42 after being excited by an electrical signal, such as a voltage excitation.

[0099] In one or more embodiments of this specification, referring to Figures 3 to 9, the inchworm-type piezoelectric rotary motor includes: a stator housing and a rotor rotatably arranged inside the stator housing, the stator housing providing a wall 1, and the rotor being an output shaft 2. Referring to Figure 2, the stator housing includes: a left side wall a, a right side wall b, an upper end plate c, and a lower end plate d. The front and rear ends of the stator housing are open to facilitate machining of the left side wall a and the right side wall b, such as by wire cutting.

[0100] The left side wall a, right side wall b, upper end plate c, and lower end plate d together form a rectangular frame with an open front and rear. In other embodiments, the left side wall a and right side wall b may also have arc-shaped outer surfaces. In some embodiments, a front cover plate and a rear cover plate fixed to the rectangular frame are also included, which enclose the rectangular frame.

[0101] The stator housing provides a mounting frame for the inchworm-type piezoelectric rotary motor's internal and external structures. The left side wall a and right side wall b provide flexible hinge mechanisms for mounting and positioning the drive module 3 and unlocking device 4, and provide preload for the first drive unit 31 and second drive unit 32 within the drive module 3 to ensure stable output performance of the piezoelectric ceramic. The upper end plate c, lower end plate d, front cover plate, and rear cover plate provide mounting interfaces for the left side wall a and right side wall b, covering the outer surfaces and providing a degree of protection, thus protecting the motor's internal structure and offering some dustproof protection.

[0102] In some embodiments, the unlocking device 4 is arranged using the gap between the drive module 3 and the upper end plate c and the lower end plate d, which is highly integrated, small in size and convenient for use in confined spaces.

[0103] In some embodiments, the drive module 3 and the unlocking device 4 are both integrated on the wall 1. For example, the drive module 3 and the unlocking device 4 are installed by the first mounting part 11 and the second mounting part 12 formed directly on the wall 1. Therefore, no additional mounting components are required, which further reduces the overall volume of the motor in the radial direction.

[0104] It should be noted that the dashed lines in Figures 3, 5, 6, 8, and 9 are mainly used to roughly illustrate that a solid structure can be understood as having two integrally connected parts or being formed by a fixed connection between two parts. For example, as shown in Figure 3, the integrally formed stator housing may include a left side wall a and an upper end plate c. The dashed line in the upper left of Figure 3 is used to roughly illustrate and separate the two parts, left side wall a and upper end plate c, rather than to define the start and end positions of left side wall a and upper end plate c. In addition, similar dashed lines are also marked in Figures 5, 6, 8, and 9, which will not be described in detail here.

[0105] In one or more embodiments of this specification, the inchworm-type piezoelectric rotary motor includes: a fixed guide bearing 51 disposed at one end of the output shaft 2 and a floating guide bearing 52 disposed at the other end of the output shaft 2. Referring to FIG5, in some embodiments, the fixed guide bearing 51 is disposed at the upper end plate c, and the floating guide bearing 52 is disposed at the lower end plate d. In some embodiments, the fixed guide bearing 51 guides and positions the output shaft 2, and the floating guide bearing 52 guides the output shaft 2, but allows the floating guide bearing 52 to move within a certain range. In some embodiments, the fixed guide bearing 51 and the floating guide bearing 52 are deep groove ball bearings.

[0106] Referring to Figure 6, in some embodiments, the output shaft 2 has a fixed guide bearing shoulder 24, and a locking nut 6 is provided on the output shaft 2. The locking nut 6 is threadedly engaged with the output shaft 2 and can adjust its position relative to the output shaft 2. In some embodiments, the inner ring of the fixed guide bearing 51 is located between the fixed guide bearing shoulder 24 and the locking nut 6.

[0107] Referring again to Figure 6, in some embodiments, the upper end plate c has a fixed guide bearing boss c1 and also includes an upper cover plate fixedly connected to the upper end plate c. In some embodiments, the upper cover plate is fixed to the upper surface of the upper end plate c in Figure 6, and the upper cover plate is annular and surrounds the outside of the locking nut 6. In some embodiments, the outer ring of the fixed guide bearing 51 is disposed between the fixed guide bearing boss c1 and the upper cover plate.

[0108] The positioning of the fixed guide bearing 51 is achieved by fixing the guide bearing shoulder 24, the adjustable locking nut 6, the fixed guide bearing boss c1, and the upper cover plate to restrict the inner and outer rings of the fixed guide bearing 51, thereby ensuring the position of the output shaft 2 relative to the stator housing.

[0109] Referring to Figure 8, in some embodiments, the output shaft 2 has a floating guide bearing shoulder 25, and the output shaft 2 is also fixed with a floating guide bearing retaining ring 26. In some embodiments, the inner ring of the floating guide bearing 52 is disposed between the floating guide bearing shoulder 25 and the floating guide bearing retaining ring 26.

[0110] Referring again to Figure 8, in some embodiments, the lower end plate d has a floating guide bearing boss d1. In some embodiments, the floating guide bearing boss d1 provides an upper limit for the floating guide bearing 52, but allows the floating guide bearing 52 to move axially. Based on the movable arrangement of the floating guide bearing 52, relative movement is possible between the floating guide bearing 52 and the output shaft 2, and between the floating guide bearing 52 and the lower end plate d of the stator housing, to compensate for length changes of the output shaft 2 caused by thermal deformation or manufacturing and installation errors.

[0111] Referring to Figure 9, in some embodiments, the unlocking component of the unlockable inchworm-type piezoelectric rotary motor is a fixedly installed block structure 43. The position of the block structure 43 relative to the output shaft 2 is fixed and does not interfere with the free rotation of the output shaft 2. For example, the block structure 43 is fixed on the upper end plate c and the lower end plate d of the stator housing. Since the position of the output shaft 2 relative to the stator housing is fixed, the position of the block structure 43 inside the stator housing is also fixed, so that the surface of the block structure 43 that contacts the unlocking surface of the unlocking unit 42 (i.e., the surface of the block structure 43 facing the wall 1) maintains a constant distance from the output shaft 2. At the same time, there is no contact relationship between the block structure 43 and the output shaft 2, so it does not affect the rotation of the output shaft 2.

[0112] In some embodiments, the unlocking unit 42 extends due to deformation, causing the wall 1 to move away from the block structure 43, thereby moving the wall 1 away from the output shaft 2. In some embodiments, the unlocking unit 42 can be fixed to the wall 1 and exert force on the block structure 43, or it can be fixed to the block structure 43 and exert force on the wall 1. In this embodiment, the principle by which the unlocking unit 42 moves the wall 1 away from the block structure 43 is the same as that of the aforementioned unlocking unit 42, and therefore will not be described again.

[0113] In some embodiments, the block structure may be plate-shaped, strip-shaped, or any other arbitrary shape, which can provide a support surface facing the wall 1 for supporting the unlocking unit 42, for example, supporting the unlocking surface of the unlocking unit 42, and the distance between the support surface and the axis of the output shaft 2 can be kept constant.

[0114] In some embodiments, each unlocking unit 42 is correspondingly provided with a block structure 43, that is, a corresponding support surface is provided. In other embodiments, some unlocking units 42 may share a block structure 43, for example, the unlocking surfaces of two unlocking units 42 abut against the support surface of the same block structure 43.

[0115] In some embodiments, the unlocking unit 42 may be fixed to the wall 1, with the unlocking surface of the unlocking unit 42 applying force toward the supporting surface of the block structure 43. In other embodiments, the unlocking unit 42 may be fixed to the block structure 43, with the unlocking surface of the unlocking unit 42 applying force toward the wall 1.

[0116] In some embodiments, the unlocking component of the unlockable inchworm-type piezoelectric rotary motor is a ring structure or a part of such a ring structure fixedly disposed around the output shaft 2. For example, the ring structure is fixed to the upper end plate c and the lower end plate d of the stator housing. The outer wall of the ring structure is fixed in position relative to the output shaft 2, and there is a gap between the inner wall of the ring structure and the output shaft 2, thus not interfering with the free rotation of the output shaft 2. The cooperation between the unlocking unit 42 and the ring structure is similar to the cooperation between the unlocking unit 42 and the block structure 43 described above, and will not be repeated here.

[0117] In one or more embodiments of this specification, an unlocking method for an unlockable inchworm-type piezoelectric rotary motor is provided. This method can be used when the drive module 3 is unable to disengage from the output shaft 2 due to a fault or other reasons and is self-locked, or when unlocking is required due to other needs. The unlocking method includes: continuously applying a first electrical signal excitation, such as a first voltage excitation, to the unlocking unit 42, causing the unlocking unit 42 to extend, abut against the unlocking member, such as the outer ring 412 of the unlocking bearing 41, and further extend to push the wall 1 outward (e.g., by pushing the wall 1 outward through the reaction force received after abutting against the unlocking member); the wall 1 carries the drive module 3 away from the output shaft 2.

[0118] In some embodiments, the unlocking method further includes: applying a fourth electrical signal excitation, such as a fourth voltage excitation, to the plurality of drive modules 3 to cause one or more of the plurality of drive modules 3 to contract, thereby disengaging one or more of the plurality of drive modules 3 from the output shaft 2, further reducing the risk of "scratching" between the drive modules 3 and the output shaft 2 due to contact. For example, the fourth electrical signal may be similar to the aforementioned sixth and ninth electrical signals, and the fourth electrical signal is used to cause the first module 301 of the first drive unit 31 in the drive module 3 to contract, and the first module 301 of the second drive unit 32 in the drive module 3 to contract.

[0119] It should be noted that in some cases, all drive modules 3 are damaged and cannot contract by applying electrical signals such as voltage excitation. In this case, unlocking of the output shaft 2 depends entirely on the operation of the unlocking unit 42. Since the deformation of the unlocking unit 42 is very small, the output shaft 2 may vibrate during operation, which may result in the drive modules 3 "scratching" against the output shaft 2. Driving the output shaft 2 becomes more difficult (overcoming the frictional force when "scratching" occurs), but normal driving can still be achieved. In most cases, not all drive modules 3 are damaged, or there may be an undamaged first module 301 in the first drive unit 31 or the second drive unit 32 of a certain drive module 3. In this case, by applying electrical signals such as voltage excitation to the undamaged first module 301, the undamaged drive module 3 can contract, thereby minimizing the risk of "scratching" as much as possible.

[0120] In one or more embodiments of this specification, a redundant drive mechanism is also provided, comprising: a power shaft and two or more unlockable inchworm-type piezoelectric rotary motors driveably connected to the power shaft. In some embodiments, when one of the unlockable inchworm-type piezoelectric rotary motors fails, the unlocking method described above is applied to the failed unlockable inchworm-type piezoelectric rotary motor, and the redundant unlockable inchworm-type piezoelectric rotary motors are activated.

[0121] The basic concepts have been described above. It is obvious that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this specification by those skilled in the art. Such modifications, improvements, and corrections are taught in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

Claims

1. An unlockable inchworm-type rotary motor, characterized in that, include: wall; Rotatable output shaft; A drive module that is directly or indirectly mounted on the wall to drive the output shaft to rotate; An unlocking device for disengaging the drive module from the output shaft in the unlocked state; The unlocking device includes: a fixedly disposed unlocking member and an unlocking unit disposed directly or indirectly on one of the wall and the unlocking member, wherein there is a gap between the unlocking member and the output shaft, and the unlocking unit has an unlocking surface configured to move in the radial direction of the output shaft to at least partially abut against the other of the wall and the unlocking member. The wall is configured such that when the unlocking surface abuts against the other of the wall and the unlocking member, the unlocking unit can further move in the radial direction of the output shaft and apply force to the other of the wall and the unlocking member, causing the wall to disengage the drive module from the output shaft.

2. The unlockable inchworm-type rotary motor according to claim 1, characterized in that, The unlocking unit is disposed on the wall, and the unlocking surface is configured to move in the radial direction of the output shaft to at least partially abut against the unlocking member; The wall is configured such that when the unlocking surface abuts against the unlocking member, the unlocking unit further moves in the radial direction of the output shaft and applies force to the unlocking member, enabling the wall to carry the drive module away from the output shaft. The surface of the unlocking member that contacts the unlocking surface of the unlocking unit maintains a constant distance from the output shaft.

3. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The system includes an unlocking bearing, which comprises an inner ring, an outer ring, and bearing balls disposed between the inner ring and the outer ring. The inner ring is fitted onto the output shaft, and the outer ring forms the unlocking component.

4. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The unlocking component is a fixed block structure; Alternatively, the unlocking component may be at least a portion of a ring structure fixedly disposed around the output shaft.

5. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The unlocking unit is made of piezoelectric material and is configured such that, under the excitation of a first electrical signal, it is in the unlocked state and deforms in the radial direction of the output shaft, causing the unlocking surface to move toward the unlocking member.

6. The unlockable inchworm-type rotary motor according to claim 5, characterized in that, The unlocking unit is configured such that, without the first electrical signal excitation, it is either disengaged from the unlocking member, or at a critical position about to contact the unlocking member, or at a position in contact with the unlocking member but without deforming the wall to the point that the drive module disengages from the output shaft.

7. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The unlocking device includes two unlocking units, which are respectively located on both sides of the output shaft in a certain radial direction; Alternatively, the unlocking device may include two or more unlocking units, which are arranged around the output shaft in a circumferential direction.

8. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The drive module includes a first drive unit and a second drive unit disposed on the wall, wherein the first drive unit and the second drive unit are made of piezoelectric material; The first driving unit and the second driving unit each include: a first module disposed on the wall and a second module disposed on the first module. The first module is configured to deform radially toward the center of the output shaft under the excitation of a second electrical signal, and the second module is configured to deform tangentially along the output shaft under the excitation of a third electrical signal. The first drive unit and the second drive unit are arranged in a direction parallel to the axial direction of the output shaft.

9. The unlockable inchworm-type rotary motor according to claim 8, characterized in that, It includes a plurality of drive modules arranged around the output shaft, and each drive module is correspondingly provided with at least one unlocking unit.

10. The unlockable inchworm-type rotary motor according to claim 9, characterized in that, Each of the drive modules is provided with a corresponding unlocking device, and the unlocking device is located between the first drive unit and the second drive unit of the drive module; Alternatively, each of the drive modules is provided with two unlocking devices, which are located on both sides of the drive module along the axial direction of the output shaft.

11. The unlockable inchworm-type rotary motor according to claim 2, characterized in that, The wall includes: A first mounting part for mounting the drive module; A second mounting part for installing the unlocking device; The first mounting portion has a first deformation portion on at least one side of its two sides along the axial direction of the output shaft, and the second mounting portion has a second deformation portion on at least one side of its two sides along the axial direction of the output shaft. The wall includes a first wall portion and a second wall portion, the thickness of the first wall portion is greater than the thickness of the second wall portion, and the second wall portion is capable of pivoting relative to the first wall portion about a pivot axis located in the radial plane of the output shaft in a direction toward or away from the output shaft. The first mounting portion and the second mounting portion are located on the first wall portion, and the first deformable portion and the second deformable portion are located on the second wall portion.

12. The unlockable inchworm-type rotary motor according to claim 11, characterized in that, A groove is formed at the second wall portion; or, a groove is formed between the first wall portion and the second wall portion; or, a groove is formed in a portion of the first wall portion to form the second wall portion; The groove comprises: a first portion extending radially along the output shaft inside the wall, and a second portion extending axially along the output shaft inside the wall.

13. The unlockable inchworm-type rotary motor according to claim 3, characterized in that, The output shaft includes: an unlocking bearing shoulder, an unlocking bearing retaining ring groove, and an unlocking bearing retaining ring disposed within the unlocking bearing retaining ring groove; The unlocking bearing is located between the unlocking bearing shoulder and the unlocking bearing retaining ring; The unlocking bearing is configured to be fixed to the output shaft, or to slide between the unlocking bearing shoulder and the unlocking bearing retaining ring in the axial direction of the output shaft.

14. A method for unlocking an unlockable inchworm-type rotary motor, characterized in that, The unlockable inchworm-type rotary motor according to any one of claims 1 to 13, the unlocking method comprising: A first electrical signal is continuously applied to the unlocking unit, causing the unlocking unit to extend, abut against the other of the wall and the unlocking member, and further extend to push the wall outward and cause the wall to carry the drive module away from the output shaft.

15. The unlocking method according to claim 14, characterized in that, Also includes: A fourth electrical signal is applied to the plurality of drive modules to cause one or more of the plurality of drive modules to contract in the radial direction of the output shaft, so that one or more of the plurality of drive modules disengage from the output shaft.

16. A redundant drive mechanism, characterized in that, include: A power shaft and two or more unlockable inchworm-type rotary motors connected to the power shaft, wherein the unlockable inchworm-type rotary motors are the unlockable inchworm-type rotary motors as described in any one of claims 1 to 14.

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