Piezoelectric driving focusing motor and group ball guide structure

Abstract

The utility model relates to a piezoelectric driving focusing motor and a group ball guide structure. The piezoelectric driving focusing motor comprises a moving part used for being connected with a functional device; the moving part is connected with the base; the base is connected with a driving assembly used for driving the moving part to move. The driving assembly comprises a pre-pressing piece and a piezoelectric driver; the piezoelectric actuator is provided with a friction head abutting against the moving part. The piezoelectric actuator vibrates at high frequency to drive the moving part to move relative to the base through friction between the friction head and the moving part; the pre-pressing piece is connected with the side, away from the friction head, of the piezoelectric actuator and provides pre-pressing force to enable the friction head to abut against the outer surface of the moving part. The piezoelectric module is used as a power source, and the purposes of miniaturization, large thrust, long stroke, high bandwidth, no magnetic interference, easy assembly and low cost can be achieved. A group ball structure is adopted for guiding, stress on the opposite face of the driving assembly is dispersed, the stress is more dispersed, and ball pits are avoided.

Description

Technical Field

[0001] The utility model relates to the field of optical imaging, in particular to a piezoelectric driven focusing motor. Background Art

[0002] As camera pixels increase, lenses are getting larger and heavier. Therefore, a driving mechanism that can drive heavy weights is proposed, such as SMA (Shape Memory Alloy). However, SMA can meet the requirements of large thrust, but cannot meet the requirements of long stroke and high bandwidth. Therefore, piezoelectric motors are regarded as the best solution for large thrust, long stroke and high bandwidth in the future.

[0003] The core working principle of a piezoelectric motor, as a precision piezoelectric device, is based on the inverse piezoelectric effect of piezoelectric materials. This effect allows piezoelectric materials to undergo slight deformations, i.e., slight vibrations, under the action of an external electric field. In a piezoelectric motor, the stator is usually made of piezoelectric material, and when a voltage signal of a specific frequency is applied, the stator will produce slight vibrations within this frequency range.

[0004] These tiny vibrations are cleverly converted into macroscopic motions of the mover through a carefully designed structure and friction. Whether it is linear motion or rotational motion, the piezoelectric motor can drive the mover to achieve the desired macroscopic motion through a series of complex mechanical conversions through the tiny vibrations of the stator.

[0005] Among the many piezoelectric motor designs, the L1B2 piezoelectric motor is a typical example. Its design feature is that through precise structural adjustment, the frequencies of the first-order extension mode and the second-order bending mode of the piezoelectric motor are very close. When a driving signal of a specific frequency is applied externally, the first-order extension vibration and the second-order bending vibration of the stator will couple with each other, forming an elliptical motion trajectory of the friction head.

[0006] During this elliptical motion, a strong squeezing effect will occur between the friction head of the stator and the mover. This squeezing effect is further strengthened under the action of the preload, thereby generating a sufficiently large friction force between the two. This friction force is the main source of power to drive the mover to move, allowing the mover to achieve precise linear or rotational motion under the drive of the piezoelectric motor.

[0007] In order to ensure that the piezoelectric motor can stably excite the required target vibration mode, designers need to set appropriate constraints. These constraints may include the way the stator is fixed, the waveform and frequency of the drive signal, the size of the preload, etc. By optimizing these constraints, it is possible to ensure that the piezoelectric motor has a high degree of stability and reliability during operation, thereby achieving precise control and drive.

[0008] The industry has proposed the following different types of piezoelectric motors, each with its own advantages and disadvantages. For example, in the Japanese patent with the publication number JP2015152674A, the SIDM piezoelectric block uses a slow extension and quick withdrawal driving method to allow the movable part to move forward and backward, but the pre-pressure spring is difficult to design, making it difficult to control the stroke; and the cost is high.

[0009] The patent with patent publication number WO2020 / 036157A1 uses a tuning fork piezoelectric block, and its pre-load spring is insufficient to generate a large thrust. In addition, the design and manufacture of the tuning fork spring are difficult and cannot provide accurate pre-load. Utility Model Content

[0010] In order to solve the above problems in the prior art, the utility model provides a piezoelectric driven focus motor.

[0011] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0012] A piezoelectric driven focus motor, characterized in that: it includes a moving part for connecting a functional device; the moving part is connected to a base; the base is connected to a driving component for driving the moving part to move; the driving component includes a pre-pressing piece and a piezoelectric driver; the piezoelectric driver is provided with a friction head abutting against the moving part; the piezoelectric driver vibrates at a high frequency to drive the moving part to move relative to the base through the friction between the friction head and the moving part; the pre-pressing piece is connected to a side of the piezoelectric driver away from the friction head and provides pre-pressure to abut the friction head against the outer surface of the moving part.

[0013] Furthermore, the pre-pressed part is a PCB board; the connection holes on both sides of the PCB board are fixedly connected to the bosses arranged on the base; the middle part of the PCB board is fixedly connected to the side of the piezoelectric driver away from the friction head.

[0014] Furthermore, the PCB board is electrically connected to the piezoelectric driver; the PCB board is electrically connected to the buried optical circuit in the base.

[0015] Furthermore, the pre-pressed part includes fixing parts located on both sides and fixedly connected to the bosses on the base; the fixing parts are connected to the connecting parts through the elastic parts; and the connecting parts are connected to the piezoelectric driver.

[0016] Furthermore, the fixing part is provided with a fixing hole fixedly connected to the boss; the elastic part is provided with one on each side of the connecting part; and the connecting part is connected to a side of the piezoelectric driver away from the friction head through a connecting soft board.

[0017] Furthermore, the connecting flexible board is electrically connected to the piezoelectric driver; the connecting flexible board is electrically connected to the buried optical circuit in the base.

[0018] Furthermore, a protective cover is externally connected to the base; and a Hall element for sensing the moving position of the moving part is disposed on the base.

[0019] A group ball guide structure comprises any one of the above-mentioned piezoelectric driven focus motors; at least one group ball for guiding is arranged at a position between the base and the moving part away from the driving component.

[0020] Furthermore, the group of balls includes a plurality of small balls arranged in an array; the moving part is provided with a group of ball accommodating groove for limiting the rolling position of the group of balls; the base is provided with a stop surface arranged opposite to the group of ball accommodating groove; the group of balls is arranged between the group of ball accommodating groove and the stop surface.

[0021] Furthermore, at least one guide ball for guiding is provided at a position between the base and the moving part away from the driving assembly; the guide ball is arranged along the moving direction of the moving part; and a V-groove cooperating with the guide ball is provided on both the moving part and the base.

[0022] The beneficial effects of the utility model are:

[0023] 1. Using piezoelectric modules as power sources can achieve miniaturization, high thrust, long stroke, high frequency bandwidth, no magnetic interference, easy assembly and low cost.

[0024] 2. The piezoelectric driver is fixed by using a pre-pressed piece. The structure is quite simple and has a large contact surface with the piezoelectric driver, which can better ensure the stability of the piezoelectric driver and enable it to better generate the required target vibration mode. The pre-pressure of the pre-pressed piece can be adjusted by the deformation of the pre-pressed piece with higher accuracy.

[0025] 3. Use a group ball structure for guidance to disperse the force on the opposite side of the drive component, making the stress more dispersed and avoiding ball pits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is an exploded view of an embodiment of the utility model;

[0028] Figure 2 This utility model Figure 1 Another perspective explosion diagram;

[0029] Figure 3 This utility model Figure 1 Schematic cross-section of the corresponding structure;

[0030] Figure 4 This is an exploded view of an embodiment of the utility model;

[0031] Figure 5 This utility model Figure 4 Schematic cross-section of the corresponding structure;

[0032] Figure 6 This is an exploded view of a drive assembly according to an embodiment of the present utility model;

[0033] Figure 7 This is an exploded view of an embodiment of the utility model;

[0034] Figure 8 For this utility model Figure 7 Schematic cross-section of the corresponding structure;

[0035] Fig. 9 This is an exploded view of an embodiment of the utility model;

[0036] Fig.10 This utility model Fig. 9 Schematic cross-section of the corresponding structure;

[0037] Fig.11 This is an exploded view of an embodiment of the utility model;

[0038] Fig.12 This utility model Fig.11 Schematic cross-section of the corresponding structure.

[0039] Description of reference numerals:

[0040] 100, protective cover; 200, moving part; 201, ball group accommodating groove; 210, ball group; 220, guide ball; 230, friction plate; 300, driving assembly; 310, pre-pressed part; 311, connecting hole; 312, fixing part; 313, elastic part; 314, connecting part; 315, fixing hole; 320, piezoelectric driver; 321, friction head; 330, connecting soft board; 400, base; 410, boss; 420, buried ray path; 430, stop surface; 440, V-groove; 450, Hall element. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0042] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] For example, see Figure 1The present application provides a piezoelectric driven focus motor; it includes a moving part 200 for connecting a functional device; the moving part 200 is connected to a base 400; a driving assembly 300 for driving the moving part 200 to move is connected to the base 400; the driving assembly 300 includes a pre-pressing piece 310 and a piezoelectric driver 320; the piezoelectric driver 320 is provided with a friction head 321 abutting against the moving part 200; the piezoelectric driver 320 vibrates at a high frequency to drive the moving part 200 to move relative to the base 400 through the friction between the friction head 321 and the moving part 200; the pre-pressing piece 310 is connected to a side of the piezoelectric driver 320 away from the friction head 321 and provides pre-pressure to abut the friction head 321 against the outer surface of the moving part 200;

[0045] In one embodiment, the driving assembly 300 drives the moving part 200 to move along the Z-axis direction, and the moving part 200 is connected to the lens to realize the AF function of the lens; wherein the Z-axis direction is the optical axis direction of the lens;

[0046] In one embodiment, the driving assembly 300 drives the moving part 200 to move along the X-axis and / or Y-axis direction, and when the lens is connected inside the moving part 200, the OIS function of the lens can be realized;

[0047] In one embodiment, the driving assembly 300 drives the moving part 200 to move along the Z-axis direction, and the moving part 200 is connected with a lens, so that the AF function of the lens can be realized; a base (not shown in the figure) is further provided below the base 400, and an OIS driving coil is provided on the base, and a driving magnet (not shown in the figure) matched with the OIS driving coil is provided on the base 400, and the OIS function of the lens is realized by using the OIS driving coil and the driving magnet to cooperate with each other;

[0048] In one embodiment, the functional device may be, but is not limited to, a lens, a camera module, etc.; for example, when the piezoelectric driven focus motor of the present application is a part of a camera module, the functional device is a lens, and the lens is connected to the moving part 200, and the moving part 200 is driven to move by the driving component 300, so that the camera module can realize the AF function and / or the OIS function; for example, when the piezoelectric driven focus motor of the present application is a separate part of an electronic device, the functional device is a camera module, and the driving component 300 drives the camera module to move, thus forming a telescopic camera structure;

[0049] In one embodiment, if Figure 1-3 As shown; the pre-pressed member 310 is a PCB board; the connection holes 311 on both sides of the PCB board are fixedly connected to the bosses 410 provided on the base 400; the middle part of the PCB board is fixedly connected to the side of the piezoelectric driver 320 away from the friction head 321; see Figure 3When the PCB board abuts against the piezoelectric driver 320, the PCB board undergoes elastic deformation along the direction A, so the PCB board has a tendency to recover to its original state. In this state, the PCB board will abut the massage head of the piezoelectric driver 320 against the moving part 200, and the PCB board generates a force opposite to the direction A to act on the piezoelectric driver 320; the PCB board is electrically connected to the piezoelectric driver 320; the PCB board is electrically connected to the buried line 420 in the base 400, so as to realize the power supply to the piezoelectric driver 320; the PCB board is electrically connected to the 4-pin pin on the piezoelectric driver 320, and the middle part of the PCB board is fixed to the piezoelectric driver 320 by glue;

[0050] In one embodiment, a friction plate 230 is provided on the end surface of the moving part 200 that abuts against the friction head 321; the friction head 321 abuts against the friction plate 230; by adding the friction plate 230, the friction force between the friction head 321 and the moving part 200 can be better controlled, and better motion control can be achieved; the friction plate 230 can be fixed to the moving part 200 by gluing or riveting, or can be formed by injection molding to form an integrated structure with the moving part 200;

[0051] In one embodiment, the two sides of the PCB board can be fixedly connected to the moving part 200 by screws, and the middle part of the PCB board can be connected to the piezoelectric driver 320 first. During installation, the friction head 321 abuts against the outer surface of the moving part 200. At this time, the PCB board has not yet undergone complete elastic deformation, and there is still a certain distance between the two sides of the PCB board and the base 400. The friction head 321 is connected to the moving part 200 by screws (located at Figure 3 When the two sides of the PCB are fixed on the base 400 by the middle convex column 410, the two sides of the PCB are close to the base 400, causing the PCB to bend and deform, generating a pre-pressure on the piezoelectric driver 320, and the depth of the screw directly determines the bending degree of the PCB, so that the size of the pre-pressure can be more accurately controlled;

[0052] In one embodiment, see Figure 6 The pre-compression member 310 of the driving assembly 300 includes a fixing portion 312 located on both sides and fixedly connected to the boss 410 on the base 400; the fixing portion 312 is connected to the connecting portion 314 through an elastic portion 313; the connecting portion 314 is connected to the piezoelectric driver 320; two fixing portions 312 are arranged on both sides, each connected to the middle connecting portion 314 through an elastic portion 313; the connecting portion 314 is fixedly connected to the piezoelectric driver 320; the elastic portion 313 is composed of a plurality of complete connecting arms, which can provide more sufficient pre-compression when abutting against the piezoelectric driver 320, Figure 6The elastic part 313 is only an example, and any other shape that can be bent to generate elastic force to act on the piezoelectric driver 320 to achieve the purpose of pre-tightening is acceptable; the fixing part 312 is provided with a fixing hole 315 fixedly connected to the boss 410; the fixing part 312 can also be connected by the screws described in the previous embodiment;

[0053] In one embodiment, in order to better realize the connection of the circuit, the connecting portion 314 is connected to the side of the piezoelectric driver 320 away from the friction head 321 through the connecting soft board 330, that is, the connecting soft board 330 is arranged between the connecting portion 314 and the piezoelectric driver 320; the connecting soft board 330 is provided with a contact electrically connected to the 4-pin pin on the piezoelectric driver 320; the connecting soft board 330 is electrically connected to the buried line circuit 420 in the base 400; similarly, one side of the connecting soft board 330 is electrically connected to the piezoelectric driver 320 and fixedly connected by glue, or fixed by riveting, clamping or other structures, and the other side of the connecting soft board 330 is fixedly connected to the connecting portion 314;

[0054] In one embodiment, the base 400 is externally connected to a protective cover 100, and the protective cover 100 is a non-magnetic protective cover 100; the base 400 is provided with a Hall element 450 for sensing the movement position of the moving part 200, and the Hall element 450 senses the movement position of the moving part 200 to achieve precise control;

[0055] In one embodiment, see Figure 4-6 As shown, a group ball 210 guiding structure includes the above-mentioned piezoelectric driven focus motor; at least one group ball 210 for guiding is provided at a position between the base 400 and the moving part 200 away from the driving assembly 300; the group ball 210 includes a plurality of small balls arranged in an array; the group ball 210 includes at least two rows and two columns of arrays consisting of four small balls, preferably a nine-ball array consisting of three rows and three columns, or a twelve-ball array consisting of three rows and four columns, or a twelve-ball array consisting of four rows and three columns; Figure 5 In the embodiment, two groups of balls 210 are arranged on two side surfaces of the corner on the other side of the driving assembly 300; the group of balls 210 is a 12-ball array consisting of three rows and four columns; the moving part 200 is provided with a group of ball receiving grooves 201 for limiting the rolling position of the group of balls 210, and the group of ball receiving grooves 201 are usually arranged in a square or rectangular shape; the base 400 is provided with a stop surface 430 arranged opposite to the group of ball receiving grooves 201; the group of balls 210 are arranged between the group of ball receiving grooves 201 and the stop surface 430; the group of balls 210 structure is used for guidance to disperse the force on the opposite side of the driving assembly 300, so that the stress is more dispersed, and ball pits can be avoided;

[0056] In one embodiment, see Figure 7-8As shown, three groups of balls 210 are provided, which are arranged at three corners away from the driving assembly 300, and the group of balls 210 is a 12-ball array consisting of three rows and four columns;

[0057] In one embodiment, see Figure 9-10 As shown, a group of balls 210 and three guide balls 220 are provided, and the guide balls 220 are arranged along the moving direction of the moving part 200; the moving part 200 and the base 400 are both provided with a V-shaped groove 440 that cooperates with the guide balls 220; the group of balls 210 is a 9-ball array consisting of three rows and three columns;

[0058] In one embodiment, see Figure 11-12 As shown, two groups of balls 210 are provided, which are arranged at two corners away from the driving assembly 300, and the group of balls 210 is a 12-ball array composed of three rows and four columns.

[0059] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A piezoelectric driven focus motor, characterized in that: The invention comprises a moving part (200) for connecting a functional device; the moving part (200) is connected to a base (400); a driving assembly (300) for driving the moving part (200) to move is connected to the base (400); the driving assembly (300) comprises a pre-pressing piece (310) and a piezoelectric driver (320); a friction head (321) is provided on the piezoelectric driver (320) and abuts against the moving part (200); the piezoelectric driver (320) vibrates at a high frequency to drive the moving part (200) to move relative to the base (400) through the friction between the friction head (321) and the moving part (200); the pre-pressing piece (310) is connected to a side of the piezoelectric driver (320) away from the friction head (321) and provides a pre-pressure to abut the friction head (321) against the outer surface of the moving part (200).

2. The piezoelectric driven focus motor according to claim 1, characterized in that: The pre-pressed part (310) is a PCB board; the connection holes (311) on both sides of the PCB board are fixedly connected to the bosses (410) provided on the base (400); and the middle part of the PCB board is fixedly connected to a side of the piezoelectric driver (320) that is away from the friction head (321).

3. The piezoelectric driven focus motor according to claim 2, characterized in that: The PCB board is electrically connected to the piezoelectric driver (320); and the PCB board is electrically connected to the buried ray circuit (420) in the base (400).

4. The piezoelectric driven focus motor according to claim 1, characterized in that: The pre-pressed part (310) comprises fixing parts (312) located on both sides and fixedly connected to the bosses (410) on the base (400); the fixing parts (312) are connected to the connecting parts (314) via the elastic parts (313); and the connecting parts (314) are connected to the piezoelectric driver (320).

5. The piezoelectric driven focus motor according to claim 4, characterized in that: The fixing portion (312) is provided with a fixing hole (315) fixedly connected to the convex column (410); one of the elastic portions (313) is provided on each side of the connecting portion (314); and the connecting portion (314) is connected to a side of the piezoelectric driver (320) away from the friction head (321) via a connecting soft board (330).

6. The piezoelectric driven focus motor according to claim 5, characterized in that: The connecting soft board (330) is electrically connected to the piezoelectric driver (320); the connecting soft board (330) is electrically connected to the buried ray circuit (420) in the base (400).

7. The piezoelectric driven focus motor according to claim 1, characterized in that: The base (400) is externally connected to a protective cover (100); and the base (400) is provided with a Hall element (450) for sensing the moving position of the moving part (200).

8. A group ball guide structure, characterized in that: It comprises a piezoelectric driven focus motor as described in any one of claims 1 to 7; at least one group of balls (210) for guiding is provided at a position between the base (400) and the moving part (200) away from the driving component (300).

9. A group ball guide structure according to claim 8, characterized in that: The group of rolling balls (210) comprises a plurality of small rolling balls arranged in an array; the moving part (200) is provided with a group of rolling ball accommodating groove (201) for limiting the rolling position of the group of rolling balls (210); the base (400) is provided with a stop surface (430) arranged opposite to the group of rolling ball accommodating groove (201); the group of rolling balls (210) is arranged between the group of rolling ball accommodating groove (201) and the stop surface (430).

10. The ball group guide structure according to claim 8, characterized in that: At least one guide ball (220) for guiding is also provided at a position between the base (400) and the moving part (200) away from the driving assembly (300); the guide ball (220) is arranged along the moving direction of the moving part (200); and a V-shaped groove (440) cooperating with the guide ball (220) is provided on both the moving part (200) and the base (400).

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