A cylindrical voice coil motor magnetic gravity compensator and voice coil motor and components thereof

Abstract

The present invention discloses a cylindrical voice coil motor magnetic gravity compensator and a voice coil motor and components thereof in the technical field related to voice coil motors, wherein the magnetic gravity compensator includes a mover and a stator; the mover includes a mover bracket and a mover permanent magnet, the longitudinal section of the mover bracket is U-shaped, and the mover permanent magnet is arranged at the opening of the U-shape; the stator includes a stator core, a stator magnet assembly and a stator shaft; the longitudinal section of the stator is E-shaped, the stator core is arranged on two mutually parallel sides outside the E-shape, the stator shaft is arranged on the axis in the center of the E-shape, the stator magnet assembly includes a stator permanent magnet and a stator magnetic block arranged in an overlapping manner, the stator magnet assembly is sleeved on the outer periphery of the stator shaft, and the stator permanent magnet is located between the stator magnetic block and the bottom of the E-shape; the two parallel sides of the U-shape are adapted to the two gaps formed by the three parallel sides of the E-shape; the stator has the characteristics of simple manufacturing, easy combination with the voice coil motor, good stiffness characteristics, low temperature rise, etc.

Description

Technical Field

[0001] The present invention relates to the technical field related to voice coil motors, and in particular to a magnetic gravity compensator for a cylindrical voice coil motor, a voice coil motor and components thereof. Background Art

[0002] A cylindrical voice coil motor is a linear motion actuator that converts electrical energy into mechanical energy. Unlike traditional systems that combine a servo motor with a ball screw, a voice coil motor can directly drive the load. As a result, cylindrical voice coil motors offer advantages such as simple structure, maintenance-free operation, high response, and high precision. They are widely used in applications such as semiconductors and industrial automation.

[0003] However, a common problem with existing cylindrical voice coil motors is that, when the motor is stationary, it must be constantly powered to overcome the weight of the motor and the load, resulting in energy loss. This lost energy is converted into heat and dissipated into the surrounding environment. This excess heat generation causes thermal expansion within the device, which can create difficult-to-overcome technical drawbacks for high-precision equipment and is unacceptable in high-precision applications such as lithography machines.

[0004] To address these issues, the industry has proposed a technical solution using magnetic gravity compensators to counteract gravity. This technology utilizes the magnetic field generated by permanent magnets to offset the load's gravity, eliminating the need for additional power. Furthermore, compared to mechanical coupling, magnetic coupling offers lower rigidity, allowing it to be used as a vibration isolator.

[0005] HEIDENHAIN's patent WO2011 / 131462 proposes a negative-stiffness magnetic gravity compensator structure, consisting primarily of two sets of axially magnetized annular permanent magnets and one set of axially magnetized conical permanent magnets. ORACLE's patent US6194796 proposes a classic cylindrical voice coil motor structure, but without gravity compensation. ETEL's patent US9172291 proposes a cylindrical voice coil motor with magnetic gravity compensation, with coils wound around a conical core. ASML's patent US6791443 proposes a voice coil motor with integrated magnetic gravity compensation, available in both planar and cylindrical configurations. The cylindrical structure incorporates several sets of radially magnetized permanent magnets. SMEE's patents CN105281530 and CN103034065 propose two cylindrical voice coil motors with magnetic gravity compensation.

[0006] However, although this technical problem has received widespread attention in the prior art, the magnetic gravity compensator in the prior art still has technical problems such as difficulty in combining with the voice coil motor for compact design; requiring radially magnetized permanent magnet rings, complex structure, and high cost. Summary of the Invention

[0007] In view of the technical problems in the prior art that it is difficult to combine with a voice coil motor for a compact design; a radially magnetized permanent magnet ring is required, which has a complex structure and high cost, the present invention provides a cylindrical voice coil motor magnetic gravity compensator, a voice coil motor and its components.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A magnetic gravity compensator for a cylindrical voice coil motor comprises a mover and a stator; the mover comprises a mover bracket and a mover permanent magnet, the longitudinal section of the mover bracket is U-shaped, and the mover permanent magnet is arranged at the opening of the U-shape; the stator comprises a stator core, a stator magnet assembly and a stator shaft; the longitudinal section of the stator is E-shaped, the stator core is arranged on two mutually parallel sides outside the E-shape, the stator shaft is arranged on the axis at the center of the E-shape, the stator magnet assembly comprises a stator permanent magnet and a stator magnetic block arranged in an overlapping manner, the stator magnet assembly is sleeved on the periphery of the stator shaft, and the stator permanent magnet is located between the stator magnetic block and the bottom of the E-shape; the two parallel sides of the U-shape are adapted to the two gaps formed by the three parallel sides of the E-shape.

[0010] Furthermore, there are several groups of mover permanent magnets.

[0011] A voice coil motor, based on any of the above-mentioned cylindrical voice coil motor magnetic gravity compensators, wherein the mover also includes a cable and a coil winding, the coil winding is arranged on the outer wall between the mover permanent magnet and the U-shaped bottom, and the coil winding is connected to the outside through the cable.

[0012] Furthermore, the coil windings include several groups.

[0013] Furthermore, the number of the stator magnet assemblies is equal to the sum of the number of the mover permanent magnets and the coil windings.

[0014] Furthermore, the material of the mover permanent magnet and / or the stator permanent magnet is a rare earth permanent magnet with a high magnetic energy level.

[0015] Preferably, the rare earth permanent magnet with high magnetic energy level is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet, an aluminum nickel cobalt permanent magnet or a ferrite permanent magnet.

[0016] Preferably, the stator core and / or the stator magnetic block are made of a high magnetic permeability material.

[0017] Preferably, the material of the mover bracket and / or the stator shaft is a polymer material or surface-insulated aluminum or non-magnetic stainless steel.

[0018] A magnetic gravity-compensated cylindrical voice coil motor assembly comprises a base, a linear guide rail, a spring, and a magnetic gravity-compensated cylindrical voice coil motor as described in any of the preceding items, wherein the stator is fixedly connected to the base, the mover is connected to the linear guide rail via a slider, and one end of the spring is fixedly connected to the mover and the other end is fixedly connected to the linear guide rail.

[0019] The outstanding advantages and beneficial effects of the present invention are as follows:

[0020] 1. Simple manufacturing: Compared with existing technical solutions, the permanent magnets in the technical solution of the present invention are all magnetized in the axial direction, which makes it easy to use a whole permanent magnet, making the structure and assembly simpler and reducing production costs;

[0021] 2. Easy to combine with voice coil motors: The gravity compensator structure disclosed in the present invention can be seamlessly connected with the cylindrical voice coil motor structure to form a voice coil motor with a gravity compensation module;

[0022] 3. Good stiffness characteristics: Compared with springs of the same volume, the stiffness coefficient of the gravity compensator is very low, making it suitable for use as a vibration isolator. In addition, the stiffness characteristic of the compensator is negative, and it can be used in combination with springs with the same absolute value of the stiffness coefficient to achieve gravity compensation with approximately zero stiffness.

[0023] 4. Low temperature rise: Since the gravity compensation structure offsets gravity, the Ampere force only needs to provide the force required for dynamic adjustment, thereby greatly reducing the current and heat generation, avoiding the precision error caused by thermal expansion, and is very suitable for high-precision applications such as semiconductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of the overall three-dimensional structure of the voice coil motor in the present invention;

[0026] Figure 2 Schematic diagram of the longitudinal cross-section structure of the magnetic gravity compensator of the cylindrical voice coil motor in Example 1;

[0027] Figure 3 Schematic diagram of the longitudinal cross-section structure of the magnetic gravity compensator of the cylindrical voice coil motor in Example 2;

[0028] Figure 4 Schematic diagram of the longitudinal cross-section structure of the voice coil motor in Example 3;

[0029] Figure 5 Schematic diagram of the longitudinal cross-section structure of the voice coil motor in Examples 4 and 5;

[0030] Figure 6 Schematic diagram of the three-dimensional structure of the mover of the voice coil motor in Example 4;

[0031] Figure 7 An exploded view of the stator of the voice coil motor in Example 5;

[0032] Figure 8 Magnetic field distribution diagram of the voice coil motor in Example 4 at different positions;

[0033] Figure 9 is the relationship between the suspension force and the position of the mover of the magnetic gravity compensator in Example 4;

[0034] Figure 10 The relationship between the Ampere force and the position of the mover of the voice coil motor in Example 4;

[0035] Figure 11 Schematic diagram of the structure of the magnetic gravity-compensated cylindrical voice coil motor assembly in Example 7;

[0036] In the figure: 1- mover; 2- stator; 3- cable; 4- mover bracket; 5- coil winding; 6- mover permanent magnet; 7- stator core; 8- stator permanent magnet; 9- stator magnetic block; 10- stator shaft; 11- linear guide; 12- spring; 13- load; 14- base. DETAILED DESCRIPTION

[0037] The following is a further description of specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0038] It should be noted that, in the description of the present invention, the terms "upper" and "lower" etc. indicating the orientation or positional relationship are based on the description of the structure of the present invention shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; in specific implementation, the upper and lower positional relationship of the structure in the drawings can be swapped.

[0039] In addition, unless otherwise expressly specified or limited, the terms "installed" and "connected" should be understood broadly. For example, a connection 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 an indirect connection through an intermediate medium, or it can be internal communication between two structures. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on the overall principles of the present invention and the specific context of this solution.

[0040] Example 1

[0041] like Figure 1 and Figure 2As shown, a cylindrical voice coil motor magnetic gravity compensator includes a mover 1 and a stator 2; the mover 1 includes a mover bracket 4 and a mover permanent magnet 6, the longitudinal section of the mover bracket 4 is U-shaped, and the mover permanent magnet 6 is arranged at the opening of the U-shaped, that is, the three-dimensional structure of the mover bracket 4 is a cylindrical structure with a bottom, and the mover permanent magnet 6 is arranged at the edge of one end of the opening of the cylindrical structure, or the side wall of the entire cylindrical structure is composed of the mover permanent magnet 6, or the outer periphery of the side wall of the cylindrical structure wraps the mover permanent magnet 6. The stator 2 includes a stator core 7, a stator magnet assembly and a stator shaft 10; the longitudinal section of the stator 2 is E-shaped, that is, the three-dimensional structure of the stator 2 is a cylindrical structure with a bottom and a column in the middle, the stator core 7 is arranged on two mutually parallel sides of the outer side of the E-shape, and the stator shaft 10 is arranged on the axis in the center of the E-shape, that is, the position of the stator core 7 is located on the side wall of the cylindrical structure with the column, and the stator shaft 10 is arranged at the position of the middle column, wherein the stator shaft 10 It can be a solid cylindrical shaft or a hollow cylindrical structure; the stator magnet assembly includes a stator permanent magnet 8 and a stator magnetic block 9 that are overlapped with each other, and the stator magnet assembly is sleeved on the periphery of the stator shaft 10. In specific implementation, there can also be only a stator magnet assembly without a stator shaft 10 in the middle, and the stator permanent magnet 8 is located between the stator magnetic block 9 and the bottom of the E-shape; the two parallel sides of the U-shape are adapted to the two gaps formed by the three parallel sides of the E-shape, which is expressed in three-dimensional structure, that is, the dynamic The mover 1 is generally a cylindrical structure with a bottom, and the stator 2 is generally a cylindrical structure with a bottom, except that a columnar structure is provided in the center of the cylindrical structure of the stator 2. The mover 1 and the stator 2 are matched together in that the inner diameter of the cylindrical wall of the cylindrical structure of the mover 1 is equivalent to the diameter of the columnar structure in the stator 2, the outer diameter of the cylindrical wall of the cylindrical structure of the mover 1 is equivalent to the inner diameter of the cylindrical wall of the cylindrical structure of the stator 2, and the depths of the two cylindrical structures are equivalent, so that the mover 1 and the stator 2 can achieve clearance fit.

[0042] The mover 1 and the stator 2 are concentrically assembled, and the mover 1 can make relative motion in the vertical direction relative to the stator 2. Needless to say, the magnetic pole direction of the mover permanent magnet 6 and the stator magnet assembly are the same. The magnetic poles of the two magnets achieve magnetic gravity compensation through the repulsion of like poles, avoiding heat generation when power is turned on, and can be applied to high-precision instruments.

[0043] The above is the basic type of an embodiment of the present invention. In order to improve the technical effect, the following improvements can be made to the basic type of this embodiment. The following improvements can be combined with each other where there is no contradiction. This structure can be used alone as a gravity compensator, or used in conjunction with an external voice coil motor.

[0044] Example 2

[0045] like Figure 3As shown, in the magnetic gravity compensator of the cylindrical voice coil motor, there are several groups of mover permanent magnets 6. These groups of mover permanent magnets 6 are arranged in the same manner, can provide a greater suspension force, and are suitable for applications with heavier loads.

[0046] Example 3

[0047] A voice coil motor. In the embodiment of the above-mentioned cylindrical voice coil motor magnetic gravity compensator, the mover 1 also includes a cable 3 and a coil winding 5. The coil winding 5 is arranged on the outer wall between the mover permanent magnet 6 and the U-shaped bottom, that is, the mover permanent magnet 6 is arranged on the outer wall of the lower middle part of the mover bracket 4, and the coil winding 5 is arranged on the outer wall of the upper middle part of the mover bracket 4. The coil winding 5 is connected to the outside through the cable 3; wherein the coil winding 5 is usually made of copper core or aluminum core enameled wire, and the coil winding 5 is fixed to the mover bracket 4 by gluing or other means.

[0048] like Figure 4 As shown, the mover 1 includes a set of coil windings 5 ​​and a set of mover permanent magnets 6. The mover 1 is characterized in that the length of the mover 1 is short, the mass of the mover 1 is light, but the Ampere force is small.

[0049] Example 4

[0050] like Figure 5 and Figure 6 As shown, in the voice coil motor, there are several groups of coil windings 5, which provide a larger Ampere force.

[0051] like Figure 5 As shown, the mover 1 has two sets of coil windings 5 ​​and a set of mover permanent magnets 6. In actual application, the two sets of coil windings 5 ​​and the stator permanent magnets 8 constitute a voice coil motor, which can achieve dynamic adjustment of movement.

[0052] The magnetic field of the mover permanent magnet 6 interacts with the magnetic field of the stator permanent magnet 8 to form a magnetic gravity compensator, providing a suspension force in the opposite direction to the gravity of the load 13. When the coil winding 5 is not energized, the relationship between the suspension force and the position of the mover 1 is as follows: Figure 9 As shown in the figure, within the 3mm travel range, the gravity compensator provides a characteristic similar to a "negative spring". In this preferred embodiment, the relationship between the suspension force F and the position x of the mover 1 can be expressed as: F = k·x + F0.

[0053] When combined with a spring 12 having a matching stiffness coefficient, zero-stiffness gravity compensation can be achieved, making it very suitable for applications requiring vibration isolation.

[0054] Figure 10 This is the working characteristic of the voice coil motor part in the preferred embodiment. When the coil winding 5 is passed with appropriate DC power, as shown in FIG. Figure 8 As shown, press Figure 8In the order of a, b, and c, the shallower the depth of the stator 1 in the mover 2, the greater the magnetic field distribution of the mover at different positions, which will generate an Ampere force in the magnetic field of the stator permanent magnet 8. When the current is constant, the output is related to the position. When the position is fixed, the motor output is proportional to the current. Therefore, the motion state of the workpiece can be dynamically adjusted by adjusting the current.

[0055] Figure 9 and Figure 10 The working characteristics of the decoupling analysis of the magnetic gravity compensation and the voice coil motor are respectively represented. Combining the two parts can realize the motion adjustment of the load 13 workpiece with gravity compensation.

[0056] Example 5

[0057] like Figure 5 and Figure 7 As shown, in the voice coil motor, the number of stator magnet assemblies is equal to the sum of the number of mover permanent magnets 6 and coil windings 5 ​​.

[0058] Example 6

[0059] In the voice coil motor in this embodiment, the material of the mover permanent magnet 6 and / or the stator permanent magnet 8 is a rare earth permanent magnet with a high magnetic energy level. In specific implementation, the rare earth permanent magnet with a high magnetic energy level is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet, an aluminum nickel cobalt permanent magnet or a ferrite permanent magnet. It should be explained that the use of "and / or" in this technical solution includes any one of the conjunctions having this attribute, any several of them having this attribute, and all of them having this attribute. Taking this paragraph as an example, it includes the case where only the mover permanent magnet 6 is made of a rare earth permanent magnet with a high magnetic energy level, or only the stator permanent magnet 8 is made of a rare earth permanent magnet with a high magnetic energy level, or both the mover permanent magnet 6 and the stator permanent magnet 8 are made of a rare earth permanent magnet with a high magnetic energy level. The other places where "and / or" is used are the same and will not be repeated here.

[0060] In addition, the stator core 7 and / or the stator magnetic block 9 are made of a high magnetic permeability material.

[0061] In addition, the material of the mover bracket 4 and / or the stator shaft 10 is a non-magnetic material, for example, a polymer material or surface-insulated aluminum or non-magnetic stainless steel with an insulating surface.

[0062] Example 7

[0063] like Figure 11As shown, a magnetic gravity compensation cylindrical voice coil motor assembly includes a base 14, a linear guide 11, a spring 12, and the voice coil motor of any of the above embodiments, wherein the stator 2 is fixedly connected to the base 14, the mover 1 is connected to the linear guide 11 via a slider, one end of the spring 12 is fixedly connected to the mover 1 and the other end is fixedly connected to the linear guide 11; the linear guide 11 ensures concentric installation, and the spring 12 is used to provide stiffness characteristics opposite to the magnetic gravity compensator to obtain gravity compensation with approximately zero stiffness, thereby jointly compensating for the gravity of the load 13. In practical applications, multiple springs such as Figure 11 The modules shown are used in parallel to synchronously control heavier loads 13.

[0064] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations to these embodiments may be made without departing from the principles and spirit of the present invention and without inventive effort, and these changes, modifications, substitutions, and variations still fall within the scope of protection of the present invention.

Claims

1. A magnetic gravity compensator for a cylindrical voice coil motor, characterized by: The invention comprises a mover and a stator; the mover comprises a mover bracket and a mover permanent magnet, the longitudinal section of the mover bracket is U-shaped, and the mover permanent magnet is arranged at the opening of the U-shape; the stator comprises a stator core, a stator magnet assembly and a stator shaft; the longitudinal section of the stator is E-shaped, the stator core is arranged on two mutually parallel sides outside the E-shape, the stator shaft is arranged on the axis at the center of the E-shape, and the stator magnet assembly comprises a stator permanent magnet and a stator magnet assembly which are arranged overlapping with each other. The stator magnetic conductive block, the stator magnet assembly is sleeved on the periphery of the stator shaft, the stator permanent magnet is located between the stator magnetic conductive block and the E-shaped bottom; the two parallel sides of the U-shape are adapted to the two gaps formed by the three parallel sides of the E-shape; the mover permanent magnet and the stator permanent magnet are axially magnetized; the magnetic pole directions of the mover permanent magnet and the stator permanent magnet are the same, and magnetic gravity compensation is achieved between the mover permanent magnet and the stator permanent magnet by repulsion of like poles.

2. The magnetic gravity compensator of the cylindrical voice coil motor according to claim 1, characterized in that: There are several groups of mover permanent magnets.

3. A voice coil motor, characterized in that: It includes the magnetic gravity compensator of the cylindrical voice coil motor as described in claim 1 or 2, and the mover also includes a cable and a coil winding, the coil winding is arranged on the outer wall between the mover permanent magnet and the U-shaped bottom, and the coil winding is connected to the outside through the cable.

4. The voice coil motor according to claim 3, wherein: There are several groups of coil windings.

5. The voice coil motor according to claim 3 or 4, characterized in that: The number of the stator magnet assemblies is equal to the sum of the number of the mover permanent magnets and the coil windings.

6. The voice coil motor according to claim 5, wherein: The material of the mover permanent magnet and / or the stator permanent magnet is a rare earth permanent magnet with a high magnetic energy level.

7. The voice coil motor according to claim 6, wherein: The rare earth permanent magnet with high magnetic energy level is a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet, an aluminum nickel cobalt permanent magnet or a ferrite permanent magnet.

8. The voice coil motor according to claim 5, wherein: The stator core and / or the stator magnetic block are made of a high magnetic permeability material.

9. The voice coil motor according to claim 5, wherein: The material of the mover bracket and / or the stator shaft is a polymer material or surface-insulated aluminum or non-magnetic stainless steel.

10. A magnetic gravity-compensated cylindrical voice coil motor assembly, characterized in that: It comprises a base, a linear guide rail, a spring and a voice coil motor as described in any one of claims 3 to 9, wherein the stator is fixedly connected to the base, the mover is connected to the linear guide rail through a slider, and one end of the spring is fixedly connected to the mover and the other end is fixedly connected to the linear guide rail.

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