Piezoelectric actuator for amplifying micro displacement

Abstract

An amplification mechanism comprises a first-stage amplification mechanism, a second-stage amplification mechanism and a third-stage amplification mechanism, a piezoelectric stack is arranged on the first-stage amplification mechanism, the first-stage amplification mechanism transmits the micro-displacement generated by the piezoelectric stack to the second-stage amplification mechanism in the transverse direction, and the third-stage amplification mechanism transmits the micro-displacement generated by the piezoelectric stack to the third-stage amplification mechanism. The second-stage amplification mechanism changes transverse displacement of the first-stage amplification mechanism into longitudinal displacement and amplifies the longitudinal displacement, the second-stage amplification mechanism and the first-stage amplification mechanism are both hinged to the third-stage amplification mechanism and both drive the third-stage amplification mechanism to move in the longitudinal direction, and the longitudinal movement directions are opposite; two opposite longitudinal movements are overlapped to form differential composite movement, and the third-stage amplification mechanism pushes the transmission module to rotate continuously, so that the displacement amount of micro-displacement generated by the piezoelectric stack after the micro-displacement is amplified by a structural member matched with the third-stage amplification mechanism is increased, and the friction loss during power transmission of the stator and the rotor is reduced.

Description

Technical Field

[0001] The invention relates to a piezoelectric driver for amplifying micro displacement, belonging to the technical field of precision micro machinery. Background Art

[0002] With the rapid development of science and technology, whether in traditional industries or high-end industries, human demands for product quality are becoming more and more diversified, personalized, miniaturized, automated and intelligent. The demand for precision micro-mechanical products with lightweight, modular and intelligent features is increasing, and the performance indicators of the drivers that drive precision micro-mechanical work, such as simple structure, fast response, large output torque and long service life, are also putting forward higher and higher requirements.

[0003] Piezoelectric drive is based on the inverse piezoelectric effect of piezoelectric materials. Under the action of the electric field, the piezoelectric body produces micro deformation, which is amplified by the structure that cooperates with it to produce mechanical displacement, drive the transmission mechanism to move, and output power. Piezoelectric bodies have the advantages of high displacement resolution, fast frequency response, low power loss, and strong anti-electromagnetic interference ability. Therefore, piezoelectric drives using piezoelectric bodies as energy conversion power sources occupy a very important position in the field of precision micro-mechanical drive, and have been explored and applied in the fields of micro-robots, high-precision positioning mechanisms, bioengineering, medical equipment, optical zoom systems, etc.

[0004] The common piezoelectric material is piezoelectric ceramic. When a voltage signal is applied to a piezoelectric ceramic sheet, the micro deformation generated is small. In the existing technical solution, piezoelectric ceramic sheets are often stacked and combined into a piezoelectric stack structure. After the voltage signal is applied to the piezoelectric stack, the micro deformation of each piezoelectric ceramic sheet is superimposed to generate a linear micro displacement. The driver using this method as a power source is mainly based on linear drive. At present, most of them are based on the principle of inertial impact and design different types of displacement amplification mechanisms. If rotational drive is to be achieved, the linear micro displacement of the piezoelectric stack needs to be amplified by the displacement amplification mechanism and converted into the swing displacement of the stator, driving the rotor that is in contact with the stator and applies a certain preload to rotate, thereby driving the output shaft fixed to the rotor to rotate and output power, realizing the conversion of different energy forms.

[0005] Although the rotary driver adopting the above scheme has a simple structure and is easy to implement, the stator and the rotor that are fixedly connected to the displacement amplification mechanism are in surface contact with a certain preload force. The driver that relies on friction to transmit power will have serious wear between the stator and the rotor contact surface after long-term operation, and there will be slippage or stalling. This type of driver is prone to low driving accuracy, slow response speed, small output torque, high heat generation, high energy consumption, short service life and other problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a piezoelectric driver for amplifying micro-displacement, aiming to increase the displacement of the micro-displacement generated by the piezoelectric stack after being amplified by the structural parts matched therewith and reduce the friction loss during the power transmission between the stator and the rotor, and innovate the existing micro-displacement amplification method and the power transmission method between the stator and the rotor. The driver has the advantages of high driving accuracy, fast response speed, large output torque, low energy loss, long working life, compact structure, small size, light weight, and easy miniaturization.

[0007] Preferably, the present invention provides a piezoelectric driver for amplifying micro-displacement, comprising a driving block, a transmission block and a housing; the driving block and the transmission block are both mounted on the housing; The driving block includes a piezoelectric stack and an amplifying mechanism, the amplifying mechanism includes a first-stage amplifying mechanism, a second-stage amplifying mechanism and a third-stage amplifying mechanism, the piezoelectric stack is arranged on the first-stage amplifying mechanism, the first-stage amplifying mechanism is hinged to the second-stage amplifying mechanism, and the third-stage amplifying mechanism is hinged to the first-stage amplifying mechanism and the second-stage amplifying mechanism respectively. The first-stage amplifying mechanism transmits the micro-displacement generated by the piezoelectric stack to the second-stage amplifying mechanism in the lateral direction. The second-stage amplifying mechanism changes the lateral displacement transmitted by the first-stage amplifying mechanism into a longitudinal displacement and amplifies it. The second-stage amplifying mechanism drives the third-stage amplifying mechanism to move in the longitudinal direction. The first-stage amplifying mechanism drives the third-stage amplifying mechanism to move in the longitudinal direction as well. The second-stage amplifying mechanism and the first-stage amplifying mechanism drive the third-stage amplifying mechanism to move in the longitudinal direction in opposite directions. The two reverse longitudinal movements are superimposed on each other to form a differential compound motion. The third-stage amplifying mechanism drives the transmission block to rotate continuously.

[0008] Preferably, the first-stage amplification mechanism includes a plurality of brackets and a plurality of bridge arm beams, which are connected end to end in series to form a piezoelectric stack assembly bin for mounting the piezoelectric stack, and the second-stage amplification mechanism is hinged to the brackets.

[0009] Preferably, the third-stage amplification mechanism includes a first double-arm slot-shaped beam and a first pawl, which drives the transmission assembly to rotate or prevents the transmission assembly from rotating in the opposite direction; the outer sides of the slot end and the bottom end of the lower arm beam of the first double-arm slot-shaped beam are respectively hinged to the upper ends of the first-stage amplification mechanism and the second-stage amplification mechanism, and the first pawl is a hook-type pawl or a straight-head type pawl.

[0010] Preferably, the third-stage amplification mechanism also includes a second double-arm slotted beam and a second pawl, which cooperate with the first double-arm slotted beam to prevent the transmission block from rotating in the opposite direction or drive the transmission block to rotate in the same direction; the inner sides of the slot end and the bottom end of the lower arm beam of the second double-arm slotted beam are respectively hinged to the lower ends of the first-stage amplification mechanism and the second-stage amplification mechanism, and the second pawl is a hook-type pawl.

[0011] Preferably, the second-stage amplification mechanism includes two groups of graded amplification mechanisms symmetrically arranged about the center of the first-stage amplification mechanism, wherein the graded amplification mechanism located on one side of the first-stage amplification mechanism includes a base, a support beam and a lever beam, the base is U-shaped, the support beam and the lever beam are both L-shaped, the inner middle end of the base is hinged to one end of the support beam, the other end of the support beam is hinged to one end of the short side of the lever beam, the other end of the short side of the lever beam is hinged to the first-stage amplification mechanism, and the end of the lever beam where the long side is located is hinged to the first double-arm trough beam; The graded amplification mechanism located on the other side of the first-stage amplification mechanism includes a base, a support beam and a lever beam. The base is U-shaped, and the support beam and the lever beam are both L-shaped. The middle end of the inner side of the base is hinged to one end of the support beam, and the other end of the support beam is hinged to one end of the short side of the lever beam. The other end of the short side of the lever beam is hinged to the first-stage amplification mechanism, and the end of the long side of the lever beam is hinged to the second double-arm trough beam.

[0012] Preferably, the transmission assembly includes a ratchet shaft, a sleeve, a bearing, a bearing end cover and a retaining ring, the outer edge of the ratchet in the ratchet shaft is provided with serrations, the serrations include a straight surface and an inclined surface, the sleeve, the bearing end cover and the retaining ring axially fix the bearing, and the bearing end cover and the sleeve are fastened in the housing.

[0013] Preferably, the shell includes an upper shell, a bin cover and a lower shell, the upper shell is fixedly connected to the lower shell, the upper shell is provided with a first cylindrical hole for matching the sleeve and a square hole for matching the bin cover, the first cylindrical hole is provided with a first bearing end cover groove for limiting the bearing end cover, and the square hole is provided with a bin cover groove for limiting the bin cover.

[0014] Preferably, the lower shell includes a first base arranged in different orientations for fixing the piezoelectric stack and several second bases for fixing the amplification mechanism. A second cylindrical hole for matching the sleeve is opened on the lower shell, and a second bearing end cover groove for limiting the bearing end cover is opened on the second cylindrical hole.

[0015] Preferably, the shaft in the ratchet shaft includes a shaft shoulder, an annular groove is provided on the shaft, the annular groove is located outside the shaft shoulder, and the diameter of the shaft decreases along the axial direction away from the ratchet; The sleeve comprises an inner boss and a flange, wherein the inner boss is fixedly arranged at one end of the sleeve, and the inner diameter of the inner boss is smaller than the inner diameter of the sleeve; The bearing end cover includes a first bearing end cover and a second bearing end cover, which are respectively located on both sides of the ratchet shaft, sleeve, bearing and retaining ring. The first bearing end cover is fixedly connected to the upper shell, and the second bearing end cover is fixedly connected to the lower shell.

[0016] Preferably, a plurality of reinforcing ribs are included, and a plurality of reinforcing ribs are fixedly arranged on the inner side of the first double-arm trough beam and the inner side of the second double-arm trough beam.

[0017] The beneficial effects achieved by the present invention are: The present invention proposes a piezoelectric driver for amplifying micro-displacement, which mainly includes a driving block, a transmission block and a housing. After a periodic voltage signal is applied to the piezoelectric stack in the driving block, a telescopic micro-displacement will be generated. After passing through an interference fit amplification mechanism, the micro-displacement is amplified to a certain extent, driving the end of the driving block and the transmission block to alternately mesh and transmit, converting the elastic reciprocating swinging displacement generated by the piezoelectric stack linear telescopic micro-displacement amplified by the amplification mechanism into a rotational displacement of the transmission block, outputting power, and driving the load to move. The present invention realizes step-by-step power transmission by using a double pawl to cooperate with each other and mesh with a ratchet wheel in the driving block and the transmission block, changing the friction drive mode between the existing driver driving device and the transmission device, aiming to increase the displacement of the micro-displacement generated by the piezoelectric stack after being amplified by the structural parts matched with it and reduce the friction loss during the power transmission between the stator and the rotor, innovating the existing micro-displacement amplification mode and the power transmission mode between the stator and the rotor, and proposing a piezoelectric driver for amplifying micro-displacement and a method of use. The driver has the advantages of high driving accuracy, fast response speed, large output torque, low energy loss, long working life, compact structure, small size, light weight, and easy miniaturization.

[0018] The amplification mechanism in the present invention is a compact, centrosymmetric, three-stage combined structure with multiple flexible hinges. The first-stage amplification mechanism is interference-fitted with the piezoelectric stack. The amplification mechanism is a double-bridge beam structure with equal arm lengths, with the piezoelectric stack assembly bin as the symmetry center. A piezoelectric stack assembly bin can be formed between two opposite brackets in the horizontal or vertical direction. The piezoelectric stack assembly bin is embedded in the piezoelectric stack, and the bracket and the bridge arm beam are hinged with flexible hinges. The longitudinal or lateral output displacement of the piezoelectric stack linear telescopic micro-displacement output by the amplification mechanism is effectively amplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 This is an appearance diagram of Embodiment 1 or Embodiment 2; Figure 2 This is an appearance diagram of Embodiment 3 or Embodiment 4; Figure 3 This is the general assembly diagram of the first embodiment without the upper cover; Figure 4 This is the general assembly diagram of the second embodiment without the upper cover; Figure 5 This is the general assembly diagram of the third embodiment without the upper cover; Figure 6 This is the general assembly diagram of the fourth embodiment without the upper cover; Figure 7 It is a general assembly diagram of a partial enlargement of the meshing part of the first embodiment; Figure 8 It is a general assembly diagram of a partial enlargement of the meshing part of the second embodiment; Fig. 9 This is a partial enlarged general assembly view of the meshing portion of the third embodiment; Fig.10 It is a partial enlarged general assembly drawing of the meshing part of the fourth embodiment; Fig.11 A cross-sectional view of Embodiment 1 or Embodiment 2; Fig.12 A cross-sectional view of the third or fourth embodiment; Fig.13 is a structural diagram of the driving block in the first embodiment; Fig.14 It is a structural diagram of the driving block in the second embodiment; Fig.15 This is a structural diagram of the driving block in Embodiment 3; Fig.16 This is a structural diagram of the driving block in the fourth embodiment; Fig.17 This is an appearance diagram of the first-stage amplification mechanism in Embodiment 1; Fig.18 This is an appearance diagram of the first-stage amplification mechanism in Embodiment 2; Fig.19 This is an appearance diagram of the first-stage amplification mechanism in Embodiment 3; Fig. 20 This is an appearance diagram of the first-stage amplification mechanism in Embodiment 4; Fig.21 This is an appearance diagram of the second-stage amplification mechanism in Embodiment 1; Fig. 22 This is an appearance diagram of the second-stage amplification mechanism in Embodiment 2; Fig.23 This is an appearance diagram of the second-stage amplification mechanism in Embodiment 3; Fig.24 This is an appearance diagram of the second-stage amplification mechanism in the fourth embodiment; Fig.25 This is an appearance diagram of the third-stage amplification mechanism in Embodiment 1; Fig.26 This is an appearance diagram of the third-stage amplification mechanism in Embodiment 2; Fig. 27 This is an appearance diagram of the third-stage amplification mechanism in Embodiment 3; Fig.28 This is an appearance diagram of the third-stage amplification mechanism in the fourth embodiment; Fig.29 It is the structural diagram of the transmission block; Fig.30 It is the structural diagram of the ratchet shaft; Fig.31 The figure is the shaft structure diagram of the ratchet shaft; Fig.32 It is a structural diagram of the front and back sides of the sleeve; Fig.33 It is a structural diagram of the front and back sides of the first bearing end cover; Fig.34 It is a structural diagram of the front and back sides of the second bearing end cover; Fig.35 It is a structural diagram of the front and back sides of the upper shell in the first or second embodiment; Fig.36 It is a structural diagram of the front and back sides of the upper shell in the third or fourth embodiment; Fig.37 The structural diagrams of the front and back sides of the bin cover; Fig.38 It is a structural diagram of the lower housing in Embodiment 1 or Embodiment 2; Fig.39 It is a structural diagram of the lower housing in the third embodiment or the fourth embodiment; Fig.40 It is a structural diagram of the reverse side of the lower housing in Embodiment 1 or Embodiment 2; Fig.41 This is the principle diagram of the periodic sawtooth wave signal applied by the device; Meaning of reference numerals: 1. driving assembly; 11. piezoelectric stack; 12. amplifying mechanism; 121. first-stage amplifying mechanism; 1211. bracket; 1212. piezoelectric stack assembly compartment; 1213. bridge arm beam; 122. second-stage amplifying mechanism; 1221. base; 1222. support beam; 1223. lever beam; 1224. screw hole; 123. third-stage amplifying mechanism; 1231. first double-arm trough beam; 1232. second double-arm trough beam; 1233. first ratchet; 1234. second ratchet; 2. Transmission assembly; 21, ratchet shaft; 211, ratchet; 212, shaft; 2121, shaft shoulder; 2122, annular groove; 22, sleeve; 221, inner boss; 222, flange; 23, bearing; 24, bearing end cover; 241, first bearing end cover; 242, second bearing end cover; 25, retaining ring; 3, housing; 31, upper housing; 311, first cylindrical hole; 312, square hole; 32, compartment cover; 33, lower housing; 331, first pedestal; 332, second pedestal; 333, second cylindrical hole. DETAILED DESCRIPTION

[0021] In addition, if the descriptions of "first" and "second" etc. are involved in the present invention, they are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] See also Figure 1 to Figure 12 The present application provides a piezoelectric driver for amplifying micro displacement. The driver mainly consists of a driving block 1, a transmission block 2 and a housing 3. The piezoelectric stack 11 in the driving block 1 applies a periodic voltage signal (see Fig.41 ) will generate telescopic micro displacement, and after passing through the interference fit amplifying mechanism 12, the micro displacement is amplified to a certain extent, driving the end of the driving block 1 and the transmission block 2 to alternately mesh and transmit, converting the elastic reciprocating swing displacement generated by the linear telescopic micro displacement of the piezoelectric stack 11 after amplification by the amplifying mechanism 12 into the rotational displacement of the transmission block 2, outputting power, and driving the load to move. The initial state of the piezoelectric driver is that the two pawls 1233 and 1234 at the end of the amplifying mechanism 12 in the driving block 1 are inserted into the tooth grooves of the ratchet 211 of the transmission block 2. That is, the working surface of one pawl is in direct contact with the sawtooth of the ratchet 211, and the end surface of the other pawl is in contact with the inclined surface of the sawtooth of the ratchet 211.

[0023] The driving assembly 1 includes two parts: a piezoelectric stack 11 and an amplifying mechanism 12. The piezoelectric stack 11 is a regular hexagonal prism structure, embedded in a piezoelectric stack assembly bin 1212 formed between two brackets 1211 of the amplifying mechanism 12, and has an interference fit with the brackets 1211. After a periodic voltage signal is applied, the periodic linear telescopic micro-displacement generated in the longitudinal direction (height direction) of the piezoelectric stack 11 is transmitted to the amplifying mechanism 12. Example

[0024] See also Fig.17 , Fig.21 and Fig.25 The amplification mechanism 12 is a compact, centrosymmetric, three-stage combined structure with multiple flexible hinges. The first-stage amplification mechanism 121 is interference-fitted with the piezoelectric stack 11. The amplification mechanism 121 is a double-bridge beam structure with equal arm lengths, with the piezoelectric stack assembly bin 1212 as the symmetry center. A piezoelectric stack assembly bin 1212 can be formed between two opposite brackets 1211 in the horizontal direction. The piezoelectric stack assembly bin 1212 is embedded with the piezoelectric stack 11. The bracket 1211 and the bridge arm beam 1213 are both hinged with flexible hinges. The longitudinal or lateral output displacement of the linear telescopic micro-displacement of the piezoelectric stack 11 after passing through the amplification mechanism 12 is effectively amplified.

[0025] The second-stage amplifying mechanism 122 is a Scott-Russell structure. The second-stage amplifying mechanism 122 is symmetrically and flexibly hinged on the bracket 1211 at the two lateral output ends of the first-stage amplifying structure 121, and is combined with the first-stage amplifying mechanism 121 to form a central symmetrical structure. The second-stage amplifying mechanism 122 is composed of three parts: a base 1221, a support beam 1222, and a lever beam 1223. The base 1221 is a beam structure with a U-shaped groove. Screw holes 1224 are set on the U-shaped groove arm and fixed to the housing 3 by screws. The support beam 1222 and the lever beam 1223 are both L-shaped structures. The inner middle end of the base 1221 is hinged to one end of the long side of the support beam 1222, and one end of the short side of the support beam 1222 is hinged to one end of the short side of the lever beam 1223. The other end of the short side of the lever beam 1223 is hinged to the first-stage amplifying mechanism 121, and one end of the long side of the lever beam 1223 is hinged to the third-stage amplifying mechanism 123. During operation, in addition to the swing of the lever beam 1223 compared to the support beam 1222, the support beam 1222 also swings compared to the base 1221, forming a superposition effect. Therefore, the second-stage amplification mechanism 122 changes the lateral displacement of the input end of the lever beam 1223 into the longitudinal displacement of the output end while also amplifying the displacement.

[0026] The third-stage amplification mechanism 123 is a differential double-arm trough beam structure. The double-arm trough beams 1231 and 1232 are arranged up and down with the ratchet shaft 21 as the center. The first pawl 1233 and the second pawl 1234 are respectively arranged at one end of the double-arm trough beams 1231 and 1232. Both pawls are hook-type pawls, which respectively drive the transmission block 2 to rotate or prevent the transmission block 2 from rotating in the opposite direction. Reinforcement ribs are arranged inside the double-arm trough beams 1231 and 1232 to enhance the rigidity of the beam structure. The outer side of the notch end and the bottom end of the groove of the lower arm beam of the first double-arm trough beam 1231 and the inner side of the notch end and the bottom end of the groove of the lower arm beam of the second double-arm trough beam 1232 are respectively hinged to the first-stage amplification mechanism 121 and the second amplification mechanism 122 through flexible hinges. The hinge point where the third-stage amplifying mechanism 123 and the second-stage amplifying mechanism 122 are hinged not only serves as the swing fulcrum of the third-stage amplifying mechanism 123, but also serves as the displacement output end of the second-stage amplifying mechanism 122, and can also drive the third-stage amplifying mechanism 123 to move in the longitudinal direction. The hinge point where the third-stage amplifying mechanism 123 and the first-stage amplifying mechanism 121 are hinged is the displacement input end of the third-stage amplifying mechanism 123, that is, the displacement output end of the first-stage amplifying mechanism 121. Under the joint action of the displacement of the output end of the first-stage amplifying mechanism 121 and the second-stage amplifying mechanism 123, the two ratchets 1233 and 1234 located at one end of the double-arm trough beams 1231 and 1232 swing around their respective swing fulcrums and move up and down in the longitudinal direction. The two movements are superimposed on each other to form a differential compound movement, which increases the working stroke of the two ratchets 1233 and 1234, so that the driving displacement of the driving transmission block 2 is larger.

[0027] See also Figure 29~Figure 34 The transmission block 2 includes four parts: a ratchet shaft 21, a sleeve 22, a bearing 23 and a bearing end cover 24. The gear teeth in the ratchet shaft 21 are distributed on the outer edge of the ratchet 211 and are a sawtooth structure. The sawtooth includes a straight surface and an inclined surface. The two pawls 1233 and 1234 meshing with the ratchet 211 are respectively inserted into the sawtooth grooves, pushing the sawtooth straight surface to move and slide on the sawtooth inclined surface, driving the ratchet 211 to achieve unidirectional stepping rotation.

[0028] The shaft 212 in the ratchet shaft is a cylindrical structure with multiple shoulders. The shoulder 2121 is used to locate one end face of the inner ring of the bearing 23, and an annular groove 2122 is provided near both ends of the shaft 212 to locate the other end face of the inner ring of the bearing 23 after the retaining ring 25 is placed.

[0029] The sleeve 22 is a cylindrical structure having a flange 222 and an inner boss 221. The inner boss 221 is used to locate one end face of the outer ring of the bearing 23. The flange 222 is evenly provided with screw holes in the circumference and is fixed to the housing 3 by screws.

[0030] The bearing 23 is a ball bearing, and the inner and outer ring end faces of the bearing 23 are positioned by the shaft shoulder 2121, the retaining ring 25, the inner shoulder 221 of the sleeve and the bearing end cover 24 to limit the axial stringing of the ratchet shaft 21 during operation.

[0031] The bearing end cover 24 includes a first bearing end cover 241 and a second bearing end cover 242. Both bearing end covers 241 and 242 are cylindrical structures with flanges, and the end faces of the cylinders are used to position the outer ring of the bearing 23. The screw holes uniformly distributed in the circumferential direction of the flange of the bearing end cover 24, the screw holes uniformly distributed in the circumferential direction of the flange of the sleeve 22, and the screw holes at the installation position of the housing 3 are processed together, wherein the flange of the first bearing end cover is provided with a through hole to facilitate the assembly of the ratchet shaft 21.

[0032] See also Figure 35~Figure 40 The housing 3 includes three parts: an upper housing 31, a bin cover 32 and a lower housing 33. The upper housing 31 is a square structure with a boss on the end face, and each side surface is transitioned by an arc surface. The boss is used for positioning when assembling with the lower housing 33 to ensure assembly accuracy and effective transmission of power between the drive block 1 and the transmission block 2. The upper end face of the upper housing 31 is provided with a first cylindrical hole 311 with a groove of the bearing end cover 241 and a square hole 312 with a groove of the bin cover 32. Screw holes are evenly distributed circumferentially on the bottom surface of the groove for fixing the sleeve 22, the first bearing end cover 241 and the bin cover 32 of the piezoelectric stack assembly bin. Screw holes are symmetrically arranged on the edge of the end face of the upper housing 31 to facilitate fixing with the lower housing 33.

[0033] The compartment cover 32 is a rectangular parallelepiped structure with a flange. The rectangular parallelepiped is used to position with the square hole 312 provided in the upper shell 31. The flange is symmetrically and evenly provided with screw holes in the circumference, and is fixed to the upper shell 31 by screws to seal the piezoelectric stack assembly compartment 1212.

[0034] The lower shell 33 is a square box-shaped structure with a groove embedded in the upper end face of the side wall, and the inner and outer sides are both transitioned by arc surfaces. The bottom surface is provided with rectangular pedestals 331 and 332, which are used to fix the piezoelectric stack 11 and the amplifying mechanism 12, reduce the friction between the amplifying mechanism 12 and the lower shell 33 when the driver is working, and facilitate the two pawls 1233 and 1234 at the end of the amplifying mechanism 12 to alternately push the ratchet shaft 21 in the transmission block 2 to rotate continuously in a step-by-step manner. The lower bottom surface of the lower shell 33 is provided with a second cylindrical hole 333 with a groove of the bearing end cover 242, and screw holes are evenly distributed around the bottom surface of the groove for installing the sleeve 22 and the second bearing end cover 242. The surface of the groove embedded in the lower shell 33 is symmetrically matched with the outer edge end face of the upper shell 31 to process screw holes for fixing the upper shell 31.

[0035] The working method of embodiment 1 is as follows: See also Figure 3 , Figure 7 and Fig.41After applying the rising edge sawtooth wave voltage signal, the piezoelectric stack 11 stretches longitudinally (in the height direction), and the micro displacement is amplified by the amplifier mechanism 12 with interference fit therewith. The first ratchet 1233 at the end of the third-stage amplifying mechanism 123 directly contacts the sawtooth of the ratchet 211 with its hinge point flexibly hinged with the second-stage amplifying mechanism 122 as the center, and swings toward the ratchet 211 under the joint action of the driving displacement of the driving end at the flexible hinged position with the bracket 1211 at one end of the output end of the first-stage amplifying mechanism 121 and the driving displacement of the output end of the second-stage amplifying mechanism 122. The working surface of the ratchet 1233 pushes the sawtooth of the ratchet 211 to move directly at the top of the ratchet 211. The drive transmission block 2 rotates; the second pawl 1234 located on the other side of the end of the third-stage amplification mechanism 123 is centered on the hinge point flexibly hinged with the other second-stage amplification mechanism 122, and swings away from the direction of the ratchet 211 under the combined action of the driving displacement of the driving end at the flexible hinge with the other output end bracket 1211 of the first-stage amplification mechanism 121 and the driving displacement of the output end of the other second-stage amplification mechanism 122. The end face of the pawl 1234 slides at the bottom of the ratchet 211 along the serrated inclined surface of the ratchet 211 in contact with it, preventing the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1233, and the ratchet shaft 21 rotates around its own axis.

[0036] At the moment when the pawl 1234 slides out of the sawtooth slope of the ratchet 211, that is, when the ratchet shaft 21 rotates through a sawtooth angle, the voltage signal becomes a falling sawtooth wave signal, the piezoelectric stack 11 shrinks longitudinally and returns to its initial state, the amplifier mechanism 12 with interference fit therewith is reset, and the two pawls 1233 and 1234 at the end of the third-stage amplifier mechanism 123 are centered on the hinge point flexibly hinged with their respective second-stage amplifier mechanisms 122. Under the joint action of the driven displacement at the flexible hinge of the two brackets 1211 at the output end of the first-stage amplifier mechanism 121 and the driven displacement at the output end of the second-stage amplifier mechanism 122, each of them elastically resets and swings in the opposite direction, the pawl 1234 drives the transmission block 2 to rotate, and the pawl 1233 prevents the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1234. The pawl 1234 pushes the sawtooth surface of the ratchet 211 at the bottom of the ratchet 211 to continue rotating around its own axis in the original rotation direction, and the pawl 1233 on the other side slides along the adjacent sawtooth inclined surface of the sawtooth of the ratchet 211 at the top of the ratchet 211 until the moment of sliding out of the inclined surface, that is, the ratchet shaft 21 rotates another sawtooth angle. The voltage signal changes into a falling edge sawtooth wave signal again, and the piezoelectric stack 11 generates a micro displacement again. After being amplified by the amplifying structure 12 with interference fit, the two pawls 1233 and 1234 drive the transmission block 2 to rotate under the joint action of the above-mentioned respective rotation centers and the driving end driving displacement. The pawl 1233 and 1234 interchange their working functions again, pushing the ratchet shaft 21 to continue rotating in the same direction and output power.

[0037] After the driver is supplied with a periodic sawtooth voltage signal, the two ratchets 1233 and 1234 in the driving block 1 drive the ratchet 211 to rotate and prevent the ratchet 211 from rotating in reverse, and drive the ratchet shaft 21 in the transmission block 2 to rotate continuously in the same direction, output power, and drive the load to rotate. Example

[0038] See also Fig.18 , Fig. 22 and Fig.26 The first-stage amplifying mechanism 121 and the second-stage amplifying mechanism 122 in the amplifying mechanism 12 are the same as those in the first embodiment.

[0039] The double-armed slot beams 1231 and 1232 in the third-stage amplification mechanism 123 are arranged left and right with the ratchet shaft 21 as the center. The first pawl 1233 provided at one end of the first double-armed slot beam 1231 is a straight-headed pawl, and the second pawl 1234 provided at one end of the second double-armed slot beam 1232 is a hook-headed pawl. The remaining structures are the same as those in the first embodiment, and the transmission block 2 and the housing 3 are the same as those in the first embodiment.

[0040] The working method of the second embodiment is as follows: See also Figure 4 , Figure 8 and Fig.41 After applying the rising sawtooth wave voltage signal, the piezoelectric stack 11 stretches longitudinally (in the height direction), and the micro-displacement is amplified by the amplifying mechanism 12 with interference fit therewith. The working surface of the pawl 1233 at the end of the amplifying mechanism pushes the sawtooth of the ratchet 211 to move in the straight surface on the left side of the ratchet 211, driving the transmission block 2 to rotate; the end surface of the pawl 1234 on the other side slides on the right side of the ratchet 211 along the sawtooth inclined surface of the ratchet 211 in contact with it, preventing the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1233, and the ratchet shaft 21 rotates around its own axis.

[0041] At the moment when the pawl 1234 slides out of the sawtooth inclined surface of the ratchet wheel 211, the voltage signal changes to a falling sawtooth wave signal, the piezoelectric stack 11 shrinks longitudinally, the amplifying mechanism 12 with interference fit resets, the pawl 1234 drives the transmission block 2 to rotate, and the pawl 1233 prevents the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1234. The pawl 1234 hooks the sawtooth straight surface of the ratchet wheel 211 on the right side of the ratchet wheel 211 and continues to rotate around its own axis in the original rotation direction, and the pawl 1233 on the other side slides on the adjacent sawtooth inclined surface of the sawtooth of the ratchet wheel 211 originally pushed on the left side of the ratchet wheel 211 until the moment of sliding out of the inclined surface, the voltage signal changes to a rising sawtooth wave signal and continues to pass a periodic sawtooth wave voltage signal, and the movement mode is the same as that of the first embodiment. Example

[0042] See also Fig.19 , Fig.23 and Fig. 27 A piezoelectric stack assembly chamber 1212 may be provided between two longitudinally opposite brackets 1211 of the first-stage amplifying mechanism 121 in the amplifying mechanism 12. The piezoelectric stack assembly chamber 1212 is embedded with the piezoelectric stack 11. The remaining structures are the same as those of the first embodiment.

[0043] The second-stage amplification mechanism 122 consists of three parts: a base 1221, a support beam 1222 and a lever beam 1223. The base 1221 is a beam structure with a U-shaped groove. The support beam 1222 and the lever beam 1223 are both L-shaped structures. The middle end of the inner side of the base 1221 is hinged to the end where the short side of the support beam 1222 is located, and the end where the long side of the support beam 1222 is located is hinged to the end where the short side of the lever beam 1223 is located. The rest of the structure is the same as that of Example 1.

[0044] The double-armed slotted beams 1231 and 1232 in the third-stage amplification mechanism 123 are arranged up and down with the ratchet shaft 21 as the center. The first pawl 1233 and the second pawl 1234 respectively arranged at one end of the double-armed slotted beams 1231 and 1232 are hook-type pawls, and the rest of the structure is the same as in the first embodiment. The transmission block 2 is the same as in the first embodiment. In the housing 3, except that the square hole 312 with the groove of the compartment cover 32 opened in the upper housing 31 is changed from the horizontal opening of the first or second embodiment to the vertical opening, the rest of the structure is the same as in the first embodiment.

[0045] The working method of embodiment 3 is as follows: See also Figure 5 , Fig. 9 and Fig.41 After applying the rising sawtooth wave voltage signal, the piezoelectric stack 11 stretches longitudinally (in the height direction), and the micro-displacement is amplified by the amplifying mechanism 12 with interference fit therewith. The working surface of the pawl 1234 at the end of the amplifying mechanism pushes the sawtooth of the ratchet 211 to move in the straight surface at the bottom of the ratchet 211, driving the transmission block 2 to rotate; the end face of the pawl 1233 on the other side slides at the top of the ratchet 211 along the sawtooth inclined surface of the ratchet 211 in contact with it, preventing the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1234, and the ratchet shaft 21 rotates around its own axis.

[0046] At the moment when the pawl 1233 slides out of the sawtooth inclined surface of the ratchet wheel 211, the voltage signal changes to a falling sawtooth wave signal, the piezoelectric stack 11 shrinks longitudinally, the amplifying mechanism 12 with interference fit resets, the pawl 1233 drives the transmission block 2 to rotate, and the pawl 1234 prevents the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1233. The pawl 1233 pushes the sawtooth straight surface of the ratchet wheel 211 at the top of the ratchet wheel 211 to continue rotating around its own axis in the original rotation direction, and the pawl 1234 on the other side slides at the bottom of the ratchet wheel 211 along the adjacent sawtooth inclined surface of the ratchet wheel 211 sawtooth that was originally pushed until the moment of sliding out of the inclined surface, the voltage signal changes to a rising sawtooth wave signal and continues to pass a periodic sawtooth wave voltage signal, and the movement mode is the same as that of the first embodiment. Example

[0047] See also Fig. 20 , Fig.24 and Fig.28 The first-stage amplifying mechanism 121 and the second-stage amplifying mechanism 122 in the amplifying mechanism 12 are the same as those in the third embodiment. The arrangement of the double-arm trough beams 1231 and 1232 in the third-stage amplifying mechanism 123 is the same as that in the second embodiment. The remaining structures are the same as those in the first embodiment, the transmission block 2 is the same as that in the first embodiment, and the housing 3 is the same as that in the third embodiment.

[0048] The working method of the fourth embodiment is as follows: See also Figure 6 , Fig.10 and Fig.41 After applying the rising sawtooth wave voltage signal, the piezoelectric stack 11 stretches longitudinally (in the height direction), and the micro-displacement is amplified by the amplifying mechanism 12 with interference fit therewith. The working surface of the pawl 1234 at the end of the amplifying mechanism hooks the straight surface movement of the sawtooth of the ratchet 211 on the right side of the ratchet 211, driving the transmission block 2 to rotate; the end face of the pawl 1233 on the other side slides on the left side of the ratchet 211 along the sawtooth inclined surface of the ratchet 211 in contact with it, preventing the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1234, and the ratchet shaft 21 rotates around its own axis.

[0049] At the moment when the pawl 1233 slides out of the sawtooth inclined surface of the ratchet wheel 211, the voltage signal changes to a falling sawtooth wave signal, the piezoelectric stack 11 shrinks longitudinally, the amplifying mechanism 12 with interference fit is reset, the pawl 1233 drives the transmission block 2 to rotate, and the pawl 1234 prevents the transmission block 2 from rotating in the reverse direction of the rotation direction of the transmission block 2 driven by the pawl 1233. That is, the pawl 1233 pushes the sawtooth straight surface of the ratchet wheel 211 on the left side of the ratchet wheel 211 to continue rotating around its own axis in the original rotation direction, and the pawl 1234 on the other side slides on the right side of the ratchet wheel 211 along the adjacent sawtooth inclined surface of the ratchet wheel 211 sawtooth that was originally pushed until the moment of sliding out of the inclined surface, the voltage signal changes to a rising sawtooth wave signal and continues to pass a periodic sawtooth wave voltage signal, and the movement mode is the same as that of the first embodiment.

[0050] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the inventive schemes herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present invention are indicated by the claims.

[0051] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", "connected", and "matched" should be understood in a broad sense, which may refer to mechanical connection, internal communication between two elements, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change; Secondly: In the drawings of the embodiments of the present invention, only the structures involved in the embodiments of the present invention are involved, and other structures can refer to the general design; the above specific implementation methods further explain the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above are only specific implementation methods of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present application should be included in the protection scope of the present application.

Claims

1. A piezoelectric actuator for amplifying micro-displacement, characterized in that: It comprises a driving assembly (1), a transmission assembly (2) and a housing (3); the driving assembly (1) and the transmission assembly (2) are both mounted on the housing (3); The driving assembly (1) comprises a piezoelectric stack (11) and an amplifying mechanism (12); the amplifying mechanism (12) comprises a first-stage amplifying mechanism (121), a second-stage amplifying mechanism (122) and a third-stage amplifying mechanism (123); the piezoelectric stack (11) is arranged on the first-stage amplifying mechanism (121); the first-stage amplifying mechanism (121) is hingedly connected to the second-stage amplifying mechanism (122); the third-stage amplifying mechanism (123) is hingedly connected to the first-stage amplifying mechanism (121) and the second-stage amplifying mechanism (122); The first-stage amplifying mechanism (121) transmits the micro-displacement generated by the piezoelectric stack (11) to the second-stage amplifying mechanism (122) in the lateral direction; the second-stage amplifying mechanism (122) changes the lateral displacement transmitted by the first-stage amplifying mechanism (121) into a longitudinal displacement and amplifies it; the second-stage amplifying mechanism (122) drives the third-stage amplifying mechanism (123) to move in the longitudinal direction; the first-stage amplifying mechanism (121) drives the third-stage amplifying mechanism (123) to move in the longitudinal direction; the second-stage amplifying mechanism (122) and the first-stage amplifying mechanism (121) drive the third-stage amplifying mechanism (123) to move in the longitudinal direction in opposite directions; the two opposite longitudinal movements are superimposed on each other to form a differential compound motion; the third-stage amplifying mechanism (123) drives the transmission block (2) to rotate continuously.

2. A piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The first-stage amplification mechanism (121) comprises a plurality of brackets (1211) and a plurality of bridge arm beams (1213); the plurality of brackets (1211) and the plurality of bridge arm beams (1213) are connected end to end in series to form a piezoelectric stack assembly bin (1212) for mounting a piezoelectric stack (11); and the second-stage amplification mechanism (122) is hingedly connected to the brackets (1211).

3. A piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The third-stage amplification mechanism (123) comprises a first double-arm slot-shaped beam (1231) and a first ratchet (1233), which drives the transmission block (2) to rotate or prevents the transmission block (2) from rotating in the reverse direction; the outer sides of the slot end and the slot bottom end of the lower arm beam of the first double-arm slot-shaped beam (1231) are respectively hinged to the upper ends of the first-stage amplification mechanism (121) and the second-stage amplification mechanism (122); the first ratchet (1233) is a hook-shaped ratchet or a straight-shaped ratchet.

4. A piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The third-stage amplification mechanism (123) further comprises a second double-arm slot-shaped beam (1232) and a second ratchet (1234), which cooperate with the first double-arm slot-shaped beam (1231) to prevent the transmission block (2) from rotating in the reverse direction or drive the transmission block (2) to rotate in the same direction; the inner sides of the slot end and the slot bottom end of the lower arm beam of the second double-arm slot-shaped beam (1232) are respectively hinged to the lower ends of the first-stage amplification mechanism (121) and the second-stage amplification mechanism (122); and the second ratchet (1234) is a hook-shaped ratchet.

5. The piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The second-stage amplifying mechanism (122) comprises two groups of graded amplifying mechanisms symmetrically arranged about the center of the first-stage amplifying mechanism (121), wherein the graded amplifying mechanism located on one side of the first-stage amplifying mechanism (121) comprises a base (1221), a support beam (1222) and a lever beam (1223); the base (1221) is U-shaped, and the support beam (1222) and the lever beam (1223) are both L-shaped; the inner middle end of the base (1221) is hinged to one end of the support beam (1222); the other end of the support beam (1222) is hinged to one end of the short side of the lever beam (1223); the other end of the short side of the lever beam (1223) is hinged to the first-stage amplifying mechanism (121); and the end of the long side of the lever beam (1223) is hinged to the first double-arm trough beam (1231); The hierarchical amplification mechanism located on the other side of the first-stage amplification mechanism (121) comprises a base (1221), a support beam (1222) and a lever beam (1223); the base (1221) is U-shaped, and the support beam (1222) and the lever beam (1223) are both L-shaped; the inner middle end of the base (1221) is hinged to one end of the support beam (1222); the other end of the support beam (1222) is hinged to one end of the short side of the lever beam (1223); the other end of the short side of the lever beam (1223) is hinged to the first-stage amplification mechanism (121); and the end of the long side of the lever beam (1223) is hinged to the second double-arm trough beam (1232).

6. A piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The transmission assembly (2) comprises a ratchet shaft (21), a sleeve (22), a bearing (23), a bearing end cover (24) and a retaining ring (25); the outer edge of the ratchet (211) in the ratchet shaft (21) is provided with saw teeth, the saw teeth comprising a straight surface and an inclined surface; the sleeve (22), the bearing end cover (24) and the retaining ring (25) axially fix the bearing (23); the bearing end cover (24) and the sleeve (22) are fastened in the housing (3).

7. A piezoelectric actuator for amplifying micro-displacement according to claim 1, characterized in that: The housing (3) comprises an upper housing (31), a bin cover (32) and a lower housing (33); the upper housing (31) is fixedly connected to the lower housing (33); a first cylindrical hole (311) for matching with the sleeve (22) and a square hole (312) for matching with the bin cover (32) are provided on the upper housing (31); a first bearing end cover groove for limiting the bearing end cover (24) is provided on the first cylindrical hole (311); and a bin cover groove for limiting the bin cover (32) is provided on the square hole (312).

8. A piezoelectric actuator for amplifying micro-displacement according to claim 7, characterized in that: The lower shell comprises a first pedestal (331) arranged at different positions for fixing the piezoelectric stack (11) and a plurality of second pedestals (332) for fixing the amplification mechanism. A second cylindrical hole (333) matching the sleeve (22) is provided on the lower shell (33), and a second bearing end cover groove for limiting the bearing end cover (24) is provided on the second cylindrical hole (333).

9. A piezoelectric actuator for amplifying micro-displacement according to claim 6, characterized in that: The shaft (212) in the ratchet shaft (21) comprises a shaft shoulder (2121), an annular groove (2122) is provided on the shaft (212), the annular groove (2122) is located outside the shaft shoulder (2121), and the diameter of the shaft (212) decreases along the axial direction away from the ratchet (211); The sleeve (22) comprises an inner boss (221) and a flange (222); the inner boss (221) is fixedly arranged at one end of the sleeve (22); and the inner diameter of the inner boss (221) is smaller than the inner diameter of the sleeve (22); The bearing end cover (24) comprises a first bearing end cover (241) and a second bearing end cover (242); the first bearing end cover (241) and the second bearing end cover (242) are respectively located on both sides of the ratchet shaft (21), the sleeve (22), the bearing (23) and the retaining ring (25); the first bearing end cover (241) is fixedly connected to the upper housing (31), and the second bearing end cover (242) is fixedly connected to the lower housing (33).

10. A piezoelectric actuator for amplifying micro displacement according to claims 3 and 4, characterized in that: It comprises a plurality of reinforcing ribs, and the inner side of the first double-arm trough beam (1231) and the inner side of the second double-arm trough beam (1232) are fixedly provided with the plurality of reinforcing ribs.

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