A voice coil motor with a multi-functional magnetic shielding plate

Abstract

This invention discloses a voice coil motor with a multifunctional magnetic shielding sheet, comprising a housing, a lens carrier, an upper spring plate suspending the lens carrier within the housing, and a plurality of magnets arranged around the lens carrier. The magnetic shielding sheet is positioned between the magnets and the housing, and includes a magnetic shielding portion, anti-torsion portions at both ends of the magnetic shielding portion, and a spring fixing portion on the top surface of the anti-torsion portion. The magnetic shielding portion covers the outer side of the magnets facing the sidewall of the housing; the anti-torsion portion abuts against the sidewall of the housing; the top surface of the upper spring plate aligns with the inner top wall of the housing, and the spring fixing portion abuts against the bottom surface of the upper spring plate, pressing the upper spring plate firmly against the housing. This invention utilizes the placement and special shape of the magnetic shielding sheet to apply force to the magnet group, housing, and upper spring plate located around the three peripheries of the magnetic shielding sheet, achieving the functions of magnetic shielding for the motor, anti-torsion for the carrier, and pressing down on the upper spring plate.

Description

Technical Field

[0001] This invention relates to the technical field of voice coil motors, and more specifically, to a voice coil motor with a multifunctional magnetic shielding sheet. Background Technology

[0002] A voice coil motor, also known as a VCM motor, consists of a housing, an upper spring, a lens carrier, a coil wound around the lens carrier, a lower spring, and a base. The housing and base are stationary components, with magnets fixed around them. The coil is wound around the outer edge of the carrier and integrated with it. The carrier is suspended by the upper and lower springs within the magnetic field space of the housing's inner cavity. When the coil is energized, the carrier moves up and down under the influence of Ampere's force, thus driving the lens to focus.

[0003] Because the lens is threaded onto the carrier, industry standards require the carrier to have a certain degree of torsional resistance in the circumferential direction of the aperture. Therefore, the VCM motor must be designed with necessary anti-torsional structures. Currently, the anti-torsional structures of VCM motors are as follows: Figure 1 As shown, the outer casing is typically a metal structure. Four inverted hook-shaped stop posts A are designed on the outer casing D, and four recessed positions B are designed to cooperate with it. Because the gap between the stop posts A and the recessed positions B is very small, it can effectively stop the movement when the carrier twists along the optical aperture, preventing damage to other internal structures of the motor. However, the outer casing D is made of molded sheet metal, so the edges of the four stop posts A are inevitably sharp or have burrs. The carrier G is a thermoformed plastic material, and the contact surface between the two can easily scratch each other during stopping, generating debris and dust, leading to optical pollution. Furthermore, from a purely structural perspective, designing four stop posts A on the outer casing makes mold making more complex, increasing production difficulty and cost. Designing four recessed positions B on the carrier G also significantly sacrifices the carrier's space, compressing other necessary structural features, which is detrimental to performance and reliability.

[0004] In addition, the magnet assembly faces the outer casing directly, and its magnetic field can penetrate the plastic and casing, extending beyond the motor. This creates a risk of external magnetic interference. Modern terminal camera assemblies typically consist of several cameras grouped together, meaning several focusing motors are also very close. If the magnetic interference of one motor is too strong, it will inevitably affect the normal operation of the adjacent motors, as each motor's power comes from electromagnetic thrust. Magnetic interference can also potentially affect other electronic components.

[0005] Furthermore, such as Figure 2As shown, in the current motor structure, the upper spring C is first installed inside the housing D, and the fixing part H of the upper spring C rests against the inner boss of the housing D. Then, the magnet F is installed to press the fixing part H of the upper spring firmly against the inner boss of the housing D. However, due to space and electromagnetic performance limitations, the length of the magnet F cannot be extended to completely cover the fixing part H of the upper spring. Therefore, during violent movements and impacts, the release position E of the upper spring may still loosen.

[0006] Overall, based on the current magnet assembly installation method, the motor structure has shortcomings such as poor anti-torsion effect, magnetic field leakage, and poor upper spring compression. Summary of the Invention

[0007] The primary objective of this invention is to address the problems existing in the prior art by providing a voice coil motor with a multifunctional magnetic shielding sheet. By placing a magnetic shielding sheet between the magnet assembly and the housing, the motor structure's resistance to torsion, magnetic leakage, and loosening of the upper spring sheet are improved based on the special structure of the magnetic shielding sheet.

[0008] The technical effects to be achieved by this invention are realized through the following technical solutions:

[0009] A voice coil motor with a multifunctional magnetic shielding sheet includes a housing, a lens carrier, an upper spring plate suspending the lens carrier within the housing, and a plurality of magnets arranged around the lens carrier. The magnetic shielding sheet is disposed between the magnets and the housing. The magnetic shielding sheet includes a magnetic shielding portion, anti-torsion portions at both ends of the magnetic shielding portion, and a spring fixing portion on the top surface of the anti-torsion portion. The magnetic shielding portion covers the outer side of the magnet facing the sidewall of the housing. The anti-torsion portion abuts against the sidewall of the housing. The top surface of the upper spring plate aligns with the inner top wall of the housing, and the spring fixing portion abuts against the bottom surface of the upper spring plate, pressing the upper spring plate firmly against the housing.

[0010] Preferably, the magnetic shielding sheet has a plate-like structure, with the middle part of the magnetic shielding sheet being straight and forming the magnetic shielding part, the shape and size of which correspond to the outer surface of the magnet; the two ends of the magnetic shielding sheet are bent to form the anti-torsion part, the outer peripheral surface of which abuts against the side wall of the outer shell; the top surface of the anti-torsion part forms the spring fixing part, which abuts against the upper spring.

[0011] Preferably, the top surface of the anti-torsion part is partially raised, and the raised part is the spring fixing part, the shape and position of the top surface of the spring fixing part corresponding to the mounting part of the upper spring.

[0012] Preferably, the four corners of the inner top wall of the outer shell are provided with mounting bosses, and the mounting positions of the upper spring pieces correspond one-to-one with the mounting bosses. The top surface of the spring piece fixing part presses the upper spring piece against the mounting boss.

[0013] Preferably, the voice coil motor includes a base, which engages with the lower end of the housing to form a cavity, and the bottom surface of the magnetic shielding part abuts against the base.

[0014] Preferably, the surface of the magnetic shielding part is not smaller than the outer surface of the magnet.

[0015] Preferably, the top of the magnetic shielding part is provided with a raised edge, the length of the raised edge is not less than the length of the magnet, the width of the raised edge is not less than the width of the magnet, the raised edge is used to cover the top surface of the magnet, and the top surface of the magnet faces the inner top wall of the outer shell.

[0016] Preferably, the magnetic shielding sheet is made of steel.

[0017] Preferably, the outer casing is made of metal.

[0018] Preferably, each peripheral side of the lens carrier is provided with a magnet, and the outer side of each magnet is provided with a corresponding magnetic shielding sheet.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The present invention provides a magnetic shielding sheet between the magnet and the outer shell. The magnetic shielding sheet is bent to form a flat magnetic shielding part in the middle, a rolled anti-torsion part at both ends, and a raised spring fixing part on the top surface of both ends.

[0021] In the installed state, the magnetic shielding part covers the outer and top surfaces of the magnet, thereby isolating the magnetic field of the magnet from scattering outwards and upwards, which can overcome the risk of magnetic interference from the motor. The outer peripheral surface of the anti-torsion part abuts against the side wall of the housing, which can effectively stop the movement when the carrier twists along the light hole. Moreover, the anti-torsion part and the housing are in surface contact, and the two are made of similar materials, which can reduce the contamination of debris generated by scratches and help protect other internal structures of the motor. The spring fixing part abuts against the upper spring. According to the design of the magnetic shielding sheet itself and the installation structure of the motor, in the installed state, the spring fixing part can press the upper spring against the inner top wall of the housing, which can overcome the risk of spring loosening.

[0022] In summary, this invention utilizes the placement and special shape of the magnetic shielding sheet to apply force to the magnet group, outer shell, and upper spring sheet located on the three peripheries of the magnetic shielding sheet, thereby achieving the functions of motor magnetic shielding, carrier anti-torsion, and upper spring sheet compression. The invention is ingenious, novel, and scientifically sound. It effectively improves the installation of related components while simplifying the internal structure of the motor, and is well worth promoting its use in the field of precision optical components such as voice coil motors. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the installation of the stop post and groove position in the prior art;

[0025] Figure 2 This is a schematic diagram of the assembly of a voice coil motor in the prior art;

[0026] Figure 3 This is a disassembly diagram of this embodiment;

[0027] Figure 4 This is a three-dimensional sectional view of this embodiment;

[0028] Figure 5 This is a schematic diagram of the magnetic shielding sheet in this embodiment;

[0029] Figure 6 This is a schematic diagram of the assembly of the magnetic shielding sheet and the magnet in this embodiment;

[0030] Figure 7 This is a top view of this embodiment;

[0031] Figure 8 This is a three-dimensional schematic diagram of this embodiment;

[0032] In the diagram, A-stop post; B-groove position; C-upper spring; D-outer shell; E-upper spring extension position; F-magnet; G-carrier; H-upper spring fixing part; 1-outer shell; 2-lens carrier; 3-magnet; 4-base; 5-upper spring; 6-lower spring; 7-magnetic shield; 71-magnetic shield; 72-anti-torsion part; 73-spring fixing part; 74-protruding edge; 8-mounting boss; 9-corner. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Please see Figure 3This embodiment provides a voice coil motor with a multifunctional magnetic shielding sheet. The voice coil motor includes a housing 1, a lens carrier 2, a plurality of magnets 3 arranged around the lens carrier 2, a base 4 connected to the lower end of the housing 1, and an upper spring 5 and a lower spring 6 that suspend the lens carrier 2 within the housing 1 and the base 4. The upper spring 5 needs to be pressed against the inner top wall of the housing 1 by other components during installation.

[0035] Please see Figure 3 and Figure 4 A magnetic shielding sheet 7 is provided between the outer casing 1 and the magnet 3. Please refer to [link / reference]. Figure 5 The magnetic shielding sheet 7 has a plate-like structure, with its middle part being flat to form a magnetic shielding part 71, which is used to isolate the magnetic field of the magnet from leakage. The two ends of the magnetic shielding sheet 7 are rolled up to form anti-torsion parts 72, which are used to abut against the outer shell 1 to stop the lens carrier 2. The top surfaces of both ends of the magnetic shielding sheet 7 form spring fixing parts 73, which are used to press the upper spring 5.

[0036] The specific structures of the magnetic shielding part 71, the anti-torsion part 72, and the spring fixing part 73 are described below:

[0037] Please see Figure 6 In the installed state, the magnet 3 is close to the inner side of the magnetic shielding part 71. The shape and size of the magnetic shielding part 71 correspond to the outer surface of the magnet 3. Viewed from the side, the surface of the magnetic shielding part 71 is larger than or equal to the outer surface of the magnet 3, thereby preventing the magnetic field of the magnet 3 from diffusing outward. Please refer to... Figure 7 The purpose of setting the magnetic shielding sheet 7 is to prevent the magnetic field from directly passing through the outer shell 1, but instead to be reflected by the magnetic shielding sheet 7 and go to the other side of the magnet 3. In this embodiment, each magnet 3 is provided with a corresponding magnetic shielding sheet 7. According to this structure, the magnetic field generated by the magnet 3 can circulate in the inner cavity of the outer shell 1 without leaking out and causing magnetic interference.

[0038] Please see Figure 6 Furthermore, the top of the magnetic shielding part 71 is provided with a protruding edge 74. The length of the protruding edge 74 is not less than the length of the magnet 3, and the width of the protruding edge 74 is not less than the width of the magnet 3. The protruding edge 74 is used to shield the top surface of the magnet 3, thereby preventing the magnetic field of the magnet 3 from leaking upward.

[0039] The reason why the convex edge 74 is only placed on the top of the magnetic shielding part 71 and not on its bottom is that in actual use, the top of the magnetic shielding part 71 is close to the lens, and the lens is close to the outer surface of the camera assembly. Modern camera assemblies are usually composed of several cameras side by side, with almost no external obstruction between the lenses. This means that the tops of the several focusing motors, especially the tops of the magnetic shielding part 71, will also be very close together. The bottom of the magnetic shielding part 71 is close to the motor base, and there are corresponding motor mounting parts to separate them, so the magnetic interference here is not obvious. The end of the magnet 3 near the lens needs to be protected, so the top of the magnetic shielding part 71 has a convex edge 74 to prevent the magnetic field of the magnet 3 from leaking upwards.

[0040] Please see Figure 6 The magnetic shielding sheet 7 has its two ends bent to form the anti-torsion portion 72. The thickness of the anti-torsion portion 72 is equal to the distance from the magnetic shielding sheet 7 to the inner wall of the outer shell 1. In the installed state, the outer peripheral surface of the anti-torsion portion 72 will abut against the side wall of the outer shell 1. Specifically, the anti-torsion portion 72 is rolled up, and there are no sharp corners at the abutment position with the side wall of the outer shell 1. The rolled-up position uses rounded corners or gentle bends. The outer peripheral surface of the anti-torsion portion 72 has a certain height, which is not less than half the height of the magnet 3. Based on this height setting, the anti-torsion portion 72 and the outer shell 1 are in surface contact. The existing method of stopping the lens carrier and the outer shell is to set a stop post A on the outer shell and a corresponding groove position B on the lens carrier. The stop post A and the groove position B actually adopt a line and surface abutment method. The cross section of the stop post A impacts the inner peripheral surface of the groove to achieve stopping. This abutment method is the main cause of scratches and debris. To address the shortcomings of this technology, the present invention provides an anti-torsion part with a certain height and no sharp edges on the outer periphery. By providing a wider contact surface, the magnetic shielding sheet 7 can be reduced or even overcome from scratching the outer shell 1. There is only a large compression between the two, and there is almost no transverse cutting action, thus minimizing the risk of dust caused by scratches.

[0041] Furthermore, the magnetic shielding sheet 7 should form an inward 90° corner 9 at the position where it transitions to the anti-torsion part 72. The circumferential length of the corner 9 should be close to the thickness of the magnet 3. When the magnet 3 is inserted, the left and right sides of the magnet 3 abut against the corresponding circumferential surface of the corner 9. The left and right displacement of the magnet 3 is restricted by the corner 9, which can more comprehensively position the magnet 3 to optimize the internal structure of the motor.

[0042] The present invention designs a plate-shaped magnetic shielding sheet 7, and forms an anti-torsion part 72 by bending. The integrated material processing method makes the magnetic shielding sheet 7 easy to form, helps to reduce processing and manufacturing costs, and the bending setting can enhance the physical strength of the magnetic shielding sheet 7 itself, so that the impact resistance of the magnetic shielding sheet 7 is guaranteed to a certain extent.

[0043] Please see Figure 4 Within the motor structure, the top surface of the upper spring 5 aligns with the inner top wall of the housing 1. The top surface of the anti-torsion portion 72 forms the spring fixing portion 73, which abuts against the upper spring 5. In this embodiment, to more effectively apply the pressing action, the top surface of the anti-torsion portion 72 is partially raised; this raised portion forms the spring fixing portion 73, and the shape and position of the top surface of the spring fixing portion 73 correspond to the mounting position of the upper spring 5. Please refer to... Figure 8 The four corners of the inner top wall of the outer shell 1 are provided with mounting bosses 8. The corners of the upper spring 5 correspond one-to-one with the mounting bosses 8. The top surface of the spring fixing part 73 presses the upper spring 5 against the mounting bosses 8.

[0044] It should be further explained that the corner portion of the upper spring 5 is equivalent to the upper spring fixing part mentioned in the prior art, and is used as the pressed part to fix the upper spring 5.

[0045] The base 4 engages with the lower end of the outer casing 1 to form a cavity. The height of the magnetic shielding part 71 plus the protruding edge 74 is equal to the height of the cavity minus the height of the upper spring 5. Please refer to [link / reference]. Figure 8 Based on these dimensions, the bottom surface of the magnetic shielding part 71 will abut against the base 4 during actual installation, and the top surface of the protrusion 74 will abut against the inner top wall of the outer shell 1. The vertical displacement of the magnetic shielding sheet 7 is limited. At this time, the spring fixing part 73 presses the corner of the upper spring sheet 5 against the mounting boss 8, and the top surface of the protrusion 74 abuts against the edge of the upper spring sheet 5. Thus, the top surface of the magnetic shielding sheet 7 presses down one side and both corners of the upper spring sheet 5 together. Even under violent movement and impact, the spring extension position of the upper spring sheet 5 is not prone to loosening.

[0046] Each of the lens carrier 2 is provided with a magnet 3 on each peripheral side, and each magnet 3 is provided with a corresponding magnetic shielding sheet 7 on its outer side. Since each magnet 3 has the function of a magnetic shielding sheet 7, the magnetic field generated by the magnet 3 can circulate in the inner cavity of the outer shell 1 and will not leak out and cause magnetic interference.

[0047] In this embodiment, the outer shell 1 is made of metal, and the magnetic shielding sheet 7 is preferably made of cold-rolled steel plate. The use of materials with similar strength helps to reduce the risk of scratches. In addition, cold-rolled steel plate is easy to obtain, inexpensive, and has good magnetic conductivity, which can effectively reflect the magnetic field within the outer shell 1 and reduce external magnetic interference.

[0048] In summary, the present invention utilizes the placement and special shape of the magnetic shielding sheet 7 to apply force to the magnet 3, the outer shell 1, and the upper spring sheet 5 located around the magnetic shielding sheet 7, thereby achieving the functions of motor magnetic shielding, carrier anti-torsion, and upper spring sheet pressing.

[0049] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A voice coil motor with a multifunctional magnetic shielding sheet, comprising a housing, a lens carrier, an upper spring suspending the lens carrier within the housing, and a plurality of magnets arranged around the lens carrier, characterized in that, The device includes a magnetic shielding sheet and a base. The magnetic shielding sheet is disposed between the magnet and the outer shell. The magnetic shielding sheet includes a magnetic shielding part, anti-torsion parts located at both ends of the magnetic shielding part, and a spring fixing part located on the top surface of the anti-torsion part. The magnetic shielding part is used to cover the outer side of the magnet facing the side wall of the outer shell. The anti-torsion part abuts against the side wall of the outer shell. The top surface of the upper spring is aligned with the inner top wall of the outer shell. The spring fixing part abuts against the bottom surface of the upper spring and presses the upper spring against the outer shell. The base engages with the lower end of the outer shell to form a cavity. The magnetic shielding sheet has a plate-like structure. The middle part of the magnetic shielding sheet is straight and forms the magnetic shielding part. The shape and size of the magnetic shielding part correspond to the outer surface of the magnet. The two ends of the magnetic shielding sheet are bent to form the anti-torsion part. The outer peripheral surface of the anti-torsion part abuts against the side wall of the outer shell. The top surface of the anti-torsion part forms the spring fixing part, which abuts against the upper spring.

2. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The top surface of the anti-torsion part is partially raised, and the part after the partial raising is the spring fixing part. The shape and position of the top surface of the spring fixing part correspond to the mounting position of the upper spring.

3. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The four corners of the inner top wall of the outer shell are provided with mounting bosses. The mounting positions of the upper spring pieces correspond one-to-one with the mounting bosses. The top surface of the spring piece fixing part presses the upper spring piece against the mounting boss.

4. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The bottom surface of the magnetic shielding part abuts against the base.

5. A voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The surface of the magnetic shielding part is not smaller than the outer surface of the magnet.

6. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The top of the magnetic shielding part is provided with a protruding edge. The length of the protruding edge is not less than the length of the magnet, and the width of the protruding edge is not less than the width of the magnet. The protruding edge is used to cover the top surface of the magnet, and the top surface of the magnet faces the inner top wall of the outer shell.

7. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The magnetic shielding sheet is made of steel.

8. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, The outer shell is made of metal.

9. The voice coil motor with a multifunctional magnetic shielding sheet according to claim 1, characterized in that, Each peripheral side of the lens carrier is provided with a magnet, and the outer side of each magnet is provided with a corresponding magnetic shielding sheet.

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