A cylindrical voice coil motor structure with two degrees of freedom

Abstract

A cylindrical voice coil motor structure with two degrees of freedom relates to the technical field of voice coil motors. The overall yoke is composed of a central cylindrical section, an intermediate cylindrical section, and an outer cylindrical section and is integrally connected at the bottom end. Two movement grooves are opened on its bottom end face. The linear part permanent magnet group is sleeved and attached to the outer wall of the intermediate cylindrical section according to the Halbach distribution. The top yoke is sleeved and fixed at the top. Two arc-shaped radial permanent magnets of the deflection part permanent magnet group are attached and fixed to the inner wall of the intermediate cylindrical section. The linear bracket is a cylindrical shape with a closed top and is inserted between the outer cylindrical section and the linear part permanent magnet group. There are two linear movement coils on its outer wall. The deflection bracket is a cylindrical shape with arc-shaped arms on both sides and is sleeved outside the central cylindrical section. There is a deflection movement coil on its outer wall. The output shaft fixes the linear bracket and the deflection bracket. The arrangement of its permanent magnets reduces the mutual interference of the two degrees of freedom and operates more smoothly. The overall cylindrical structure reduces magnetic leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of voice coil motors, and particularly to a cylindrical voice coil motor structure with two degrees of freedom. Background Art

[0002] Voice coil motors have the characteristics of high response, small volume, high precision, etc. They are an electro-mechanical conversion device and are mainly applied to fields such as medical treatment, semiconductors, automobiles, aerospace, and marine vessels, including the production of electronic components, various production processes of LEDs, precision measuring instruments, etc. The working principle of a voice coil motor is that a current-carrying coil is subjected to an Ampere force in a fixed magnetic field, and the coil is driven to move by this force.

[0003] There are two existing voice coil motors with two degrees of freedom: one is a double-stator voice coil motor connected by mechanical structures such as ball splines; the other is a single-stator flat voice coil motor. Both of these two voice coil motors with two degrees of freedom have a flat voice coil motor structure, and their magnetic leakage is serious. In addition, the double-stator voice coil motor has many mechanical structures used to connect two degrees of freedom and a long output shaft, which is prone to large errors. When the two moving coils of the single-stator flat voice coil motor are close to each other, they will interact with each other, affecting the stability. Summary of the Invention

[0004] To solve the deficiencies in the background art, the present invention provides a cylindrical voice coil motor structure with two degrees of freedom. It is provided with a linear part permanent magnet group arranged in a Halbach array and two parallel linear motion coils on the outside, and a deflection part permanent magnet group and a deflection motion coil on the inside, reducing the mutual interference between the two degrees of freedom, making the operation more stable, and the overall cylindrical structure is adopted to reduce magnetic leakage.

[0005] To achieve the above object, the present invention adopts the following technical solution: A cylindrical voice coil motor structure with two degrees of freedom, including an overall yoke, a linear part permanent magnet group, a deflection part permanent magnet group, a linear bracket, a deflection bracket and an output shaft. The overall yoke is composed of three parts: a central cylindrical section, an intermediate cylindrical section and an outer cylindrical section, which are arranged coaxially in a ring sleeve from the inside to the outside and the bottom end is hermetically connected and made into one body. Two movement grooves are opened on the bottom end surface of the overall yoke between the central cylindrical section and the intermediate cylindrical section. The two movement grooves are arc-shaped and arranged symmetrically about the center. The linear part permanent magnet group includes two annular radial permanent magnets and three annular axial permanent magnets, and is coaxially sleeved and attached to the outer wall of the intermediate cylindrical section of the overall yoke according to the Halbach distribution. The top yoke is sleeved and fixed on the top of the outer wall of the intermediate cylindrical section of the overall yoke and tightly pressed on the top of the linear part permanent magnet group. The deflection part permanent magnet group includes two arc-shaped radial permanent magnets with opposite pole directions and is symmetrically arranged and attached and fixed to the inner wall of the intermediate cylindrical section of the overall yoke. The linear bracket is a cylindrical structure with a closed top, and its bottom end is coaxially inserted between the inner wall of the outer cylindrical section of the overall yoke and the linear part permanent magnet group. Two linearly moving coils are arranged in parallel up and down on the outer wall of the linear bracket. The deflection bracket is a cylindrical structure with arc-shaped arms on both sides and is coaxially sleeved outside the central cylindrical section of the overall yoke. The arc-shaped arms on both sides of the deflection bracket pass through and are smaller than the corresponding movement grooves for deflection movement. A deflection movement coil is arranged on the outer wall of the deflection bracket. The connection end of the output shaft coaxially fixes the closed end of the linear bracket and the top of the deflection bracket.

[0006] Further, the linear part permanent magnet group includes a first annular axial permanent magnet, a second annular radial permanent magnet, a third annular axial permanent magnet, a fourth annular radial permanent magnet and a fifth annular axial permanent magnet arranged from bottom to top. The Halbach distribution means that the pole directions of the second annular radial permanent magnet and the fourth annular radial permanent magnet are opposite, and the pole directions of the first annular axial permanent magnet, the third annular axial permanent magnet and the fifth annular axial permanent magnet are arranged alternately with a dislocation.

[0007] Further, a thread is provided at the root of the output shaft. The connection end of the output shaft is coaxially fixed to the top of the deflection bracket. After the output shaft passes through a through hole preset in the center of the closed end of the linear bracket, the linear bracket and the deflection bracket are fixed by screwing and tightening a nut.

[0008] Further, the linear bracket, the deflection bracket, the output shaft and the fastening nut are all made of non-magnetic materials.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention arranges a linear partial permanent magnet group with a Halbach array on the outer side, optimizing the distribution of magnetic force lines, concentrating the magnetic force lines on the outer side, enhancing the magnetic flux density of the linear motion part, while reducing the influence on the deflection partial permanent magnet group, increasing the utilization efficiency of the magnetic field, having a simple structure, reducing the mutual interference between the linear and deflection two-degree-of-freedom motions, running more smoothly, and arranging two parallel linear motion coils on the linear bracket, which helps to improve the linear thrust of the voice coil motor and reduce heat generation. Overall, based on a cylindrical structure, the magnetic leakage of the motor is effectively reduced. Description of the Drawings

[0010] Figure 1 is a longitudinal sectional schematic diagram of the structure of the voice coil motor of the present invention;

[0011] Figure 2 is a schematic diagram of the motion groove opened at the bottom of the overall yoke in the present invention;

[0012] Figure 3 is a schematic diagram of the four toroidal surfaces of the overall yoke in the present invention;

[0013] Figure 4 is a schematic diagram of the magnetic circuit distribution of the structure of the voice coil motor of the present invention.

[0014] In the figure: 1. Overall yoke; 11. First toroidal surface; 12. Second toroidal surface; 13. Third toroidal surface; 14. Fourth toroidal surface; 15. Motion groove; 16. Top yoke; 21. First annular axial permanent magnet; 22. Second annular radial permanent magnet; 23. Third annular axial permanent magnet; 24. Fourth annular radial permanent magnet; 25. Fifth annular axial permanent magnet; 3. Arc-shaped radial permanent magnet; 4. Linear bracket; 41. Linear motion coil; 5. Deflection bracket; 51. Deflection motion coil; 6. Output shaft. Detailed Embodiments

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] As Figures 1 to 4 shown, a cylindrical two-degree-of-freedom voice coil motor structure includes an overall yoke 1, a linear partial permanent magnet group, a deflection partial permanent magnet group, a linear bracket 4, a deflection bracket 5, and an output shaft 6.

[0017] Combined with Figures 1 to 3As shown, the overall yoke 1 is composed of three parts: a central cylindrical section, an intermediate cylindrical section, and an outer cylindrical section, which are arranged coaxially in a ring shape from the inside out and are integrally formed by sealing and connecting the bottom end. Two movement grooves 15 are provided on the bottom end face of the overall yoke 1 between the central cylindrical section and the intermediate cylindrical section. The two movement grooves 15 are arc-shaped and symmetrically arranged at the center, for the deflection bracket 5 to pass through and allow it to deflect at a certain angle.

[0018] Combined with Figure 1 As shown, the linear part permanent magnet group includes two annular radial permanent magnets and three annular axial permanent magnets, and is coaxially sleeved and attached to the outer wall of the intermediate cylindrical section of the overall yoke 1 according to the Halbach distribution. The top of the outer wall of the intermediate cylindrical section of the overall yoke 1 is sleeved and fixed with a top yoke 16 and tightly pressed on the top of the linear part permanent magnet group. Specifically, the linear part permanent magnet group can be divided into a first annular axial permanent magnet 21, a second annular radial permanent magnet 22, a third annular axial permanent magnet 23, a fourth annular radial permanent magnet 24, and a fifth annular axial permanent magnet 25 arranged from bottom to top. The Halbach distribution means that the magnetic pole directions of the second annular radial permanent magnet 22 and the fourth annular radial permanent magnet 24 are opposite. For example, the S pole of the second annular radial permanent magnet 22 is located on the inner side of the ring and the N pole is located on the outer side of the ring, and the S pole of the fourth annular radial permanent magnet 24 is located on the outer side of the ring and the N pole is located on the inner side of the ring. The magnetic pole directions of the first annular axial permanent magnet 21, the third annular axial permanent magnet 23, and the fifth annular axial permanent magnet 25 are arranged alternately with dislocation. For example, the S pole of the first annular axial permanent magnet 21 is located at the bottom end of the ring and the N pole is located at the top end of the ring, the S pole of the third annular axial permanent magnet 23 is located at the top end of the ring and the N pole is located at the bottom end of the ring, and the S pole of the fifth annular axial permanent magnet 25 is located at the bottom end of the ring and the N pole is located at the top end of the ring.

[0019] Combined with Figure 2 As shown, the deflection part permanent magnet group includes two arc-shaped radial permanent magnets 3 with opposite magnetic pole directions and is symmetrically arranged at the center and attached and fixed to the inner wall of the intermediate cylindrical section of the overall yoke 1. For example, the S pole of one of the arc-shaped radial permanent magnets 3 is located on the outer side of the arc and is attached to the inner wall of the intermediate cylindrical section of the overall yoke 1, and the N pole of the other arc-shaped radial permanent magnet 3 is located on the outer side of the arc and is attached to the inner wall of the intermediate cylindrical section of the overall yoke 1.

[0020] Among them, the bottom ends of both the linear part permanent magnet group and the deflection part permanent magnet group are closely attached to the inner bottom surface of the overall yoke 1.

[0021] Combined with Figure 1As shown, the linear support 4 is a cylindrical structure with a closed top end, and its bottom end is coaxially inserted between the inner wall of the outer cylindrical section of the integral yoke 1 and the linear part permanent magnet group. Two linearly moving coils 41 are arranged in parallel up and down around the outer wall of the linear support 4. The deflection support 5 is a cylindrical structure with arc-shaped arms on both sides, coaxially sleeved outside the central cylindrical section of the integral yoke 1. The arc-shaped arms on both sides of the deflection support 5 pass through and are smaller than the corresponding movement slots 15 for deflection movement. A deflection movement coil 51 is arranged in a ring around the outer wall of the deflection support 5. The connection end of the output shaft 6 coaxially fixes the closed end of the linear support 4 and the top of the deflection support 5. Threads can be provided at the root of the output shaft 6. The connection end of the output shaft 6 is coaxially fixed to the top of the deflection support 5. After the output shaft 6 passes through a perforation preset in the center of the closed end of the linear support 4, the linear support 4 and the deflection support 5 are fixed by screwing on a fastening nut.

[0022] Among them, the yoke part is made of a high-permeability material, including the integral yoke 1 and the top yoke 16. The linear support 4, the deflection support 5, the output shaft 6, and the fastening nut are all made of non-magnetic materials.

[0023] Combined with Figure 3As shown in the figure, for the convenience of description, the inner wall of the outer cylindrical section of the overall yoke 1 is defined as the first toroidal surface 11, the outer wall of the middle cylindrical section is defined as the second toroidal surface 12, the inner wall of the middle cylindrical section is defined as the third toroidal surface 13, and the side wall of the central cylindrical section is defined as the fourth toroidal surface 14. The structure of this cylindrical two-degree-of-freedom voice coil motor mainly includes a first magnetic circuit A, a second magnetic circuit B, a third magnetic circuit C, and a fourth magnetic circuit D. Among them, for the first magnetic circuit A: the magnetic induction lines start from the N pole of the fourth annular radial permanent magnet 24, and successively pass through the S pole of the fifth annular axial permanent magnet 25, the N pole of the fifth annular axial permanent magnet 25, the top yoke 16, the first toroidal surface 11, and the upper linear motion coil 41, and then return to the S pole of the fourth annular radial permanent magnet 24; for the second magnetic circuit B: the magnetic induction lines start from the N pole of the second annular radial permanent magnet 22, and successively pass through the lower linear motion coil 41, the first toroidal surface 11, the upper linear motion coil 41, the S pole of the fourth annular radial permanent magnet 24, the N pole of the fourth annular radial permanent magnet 24, the S pole of the third annular axial permanent magnet 23, and the N pole of the third annular axial permanent magnet 23, and then return to the S pole of the second annular radial permanent magnet 22; for the third magnetic circuit C: the magnetic induction lines start from the N pole of the second annular radial permanent magnet 22, and successively pass through the lower linear motion coil 41, the first toroidal surface 11, the bottom of the overall yoke 1, the S pole of the first annular axial permanent magnet 21, and the N pole of the first annular axial permanent magnet 21, and then return to the S pole of the second annular radial permanent magnet 22; for the fourth magnetic circuit D: the magnetic induction lines start from the N pole of the right arc-shaped radial permanent magnet 3, and successively pass through the deflection motion coil 51 and the central cylindrical section of the overall yoke 1, the S pole of the left arc-shaped radial permanent magnet 3, the N pole of the left arc-shaped radial permanent magnet 3, the third toroidal surface 13, and the bottom of the overall yoke 1, and then return to the S pole of the right arc-shaped radial permanent magnet 3.

[0024] When the coils of this cylindrical two-degree-of-freedom voice coil motor are energized, the linear motion coil 41 is subjected to forces in the same direction, causing the output shaft 6 to output linear motion, and the inner deflection motion coil 51 can change the output angle of the output shaft 6 to achieve two degrees of freedom. The specific motion forms are as follows:

[0025] When a clockwise current is passed through the deflection motion coil 51, the left side is subjected to the Lorentz force and the motion direction is perpendicular to the paper surface and outward, and the right side is subjected to the Lorentz force and the motion direction is perpendicular to the paper surface and inward;

[0026] When a counterclockwise current is passed through the deflection motion coil 51, the left side is subjected to the Lorentz force and the motion direction is perpendicular to the paper surface and inward, and the right side is subjected to the Lorentz force and the motion direction is perpendicular to the paper surface and outward;

[0027] When the current in the lower linear motion coil 41 enters from the left side and flows out from the right side, the current in the upper linear motion coil 41 enters from the right side and flows out from the left side. At this time, the linear bracket 4 is subjected to the Lorentz force and moves upward as a whole;

[0028] When the current of the lower linear motion coil 41 enters from the right side and flows out from the left side, the current of the upper linear motion coil 41 enters from the left side and flows out from the right side. At this time, the linear bracket 4 moves downward as a whole under the action of the Lorentz force.

[0029] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other forms of devices without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0030] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A cylindrical dual-degree-of-freedom voice coil motor structure, characterized in that: The invention comprises an integral magnetic yoke (1), a linear permanent magnet group, a deflection permanent magnet group, a linear bracket (4), a deflection bracket (5) and an output shaft (6); the integral magnetic yoke (1) is composed of a central cylindrical section, a middle cylindrical section and an outer cylindrical section arranged in a coaxial ring sleeve from inside to outside, and the bottom end is sealed and connected as a whole; the bottom end surface of the integral magnetic yoke (1) is located between the central cylindrical section and the middle cylindrical section and has two movement grooves (15); the two movement grooves (15) are arc-shaped and centrally symmetrically arranged; the linear permanent magnet group comprises two annular radial permanent magnets and three annular axial permanent magnets; The yoke (1) is a magnetic body, which is divided into a first annular axial permanent magnet (21), a second annular radial permanent magnet (22), a third annular axial permanent magnet (23), a fourth annular radial permanent magnet (24) and a fifth annular axial permanent magnet (25) arranged from bottom to top, and is coaxially mounted and abutted against the outer wall of the middle cylindrical section of the integral magnetic yoke (1) according to the Halbach distribution, wherein the Halbach distribution means that the magnetic poles of the second annular radial permanent magnet (22) and the fourth annular radial permanent magnet (24) are in opposite directions, and the first annular axial permanent magnet (21), the third annular axial permanent magnet (23) and The magnetic poles of the fifth annular axial permanent magnet (25) are arranged alternately and staggered. The top of the outer wall of the middle cylindrical section of the integral magnetic yoke (1) is fitted with a top magnetic yoke (16) and is tightly pressed onto the top of the straight portion permanent magnet group. The deflection portion permanent magnet group includes two arc-shaped radial permanent magnets (3) with opposite magnetic pole directions and are centrally symmetrically arranged and fixed to the inner wall of the middle cylindrical section of the integral magnetic yoke (1). The straight bracket (4) is a cylindrical structure with a closed top and its bottom end is coaxially inserted between the inner wall of the outer cylindrical section of the integral magnetic yoke (1) and the straight portion permanent magnet group. The outer wall of the straight bracket (4) is ring-shaped. There are two linear motion coils (41) connected in parallel up and down, the deflection bracket (5) is a cylindrical structure with arc-shaped support arms on both sides, which is coaxially mounted on the outside of the central cylindrical section of the integral magnetic yoke (1), and the arc-shaped support arms on both sides of the deflection bracket (5) pass through and are smaller than the corresponding motion grooves (15) for deflection movement, the outer wall ring of the deflection bracket (5) is provided with a deflection motion coil (51), the connecting end of the output shaft (6) coaxially fixes the closed end of the linear bracket (4) and the top of the deflection bracket (5), and the linear bracket (4), the deflection bracket (5), the output shaft (6) and the fastening nut are all made of non-magnetic conductive materials.

2. A cylindrical dual-degree-of-freedom voice coil motor structure according to claim 1, characterized in that: The output shaft (6) is provided with a thread at its root, and the connecting end of the output shaft (6) is coaxially fixed to the top of the deflection bracket (5). After the output shaft (6) passes through a preset through hole at the center of the closed end of the linear bracket (4), the linear bracket (4) and the deflection bracket (5) are fixed by screwing a fastening nut.

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