End effect suppression device, design method and cylindrical permanent magnet linear motor

Abstract

The invention discloses an end effect suppression device, a design method and a cylindrical permanent magnet linear motor, and relates to the technical field of linear motors, the end effect suppression device comprises a magnetic circuit compensation structure installed at at least one end of a primary motor; the magnetic circuit compensation structure consists of at least two layers of sleeves which are concentrically nested and are made of a high-permeability material, and an axial guide mechanism is arranged between adjacent sleeve layers, so that the inner-layer sleeve can slide along the axial direction of the motor relative to the outer-layer sleeve; the outermost layer of sleeve is fixedly connected with the end part of the primary, and the innermost layer of sleeve is arranged to be capable of keeping coupling with the secondary in the operation process of the motor, so that continuous magnetic circuit connection is formed among the secondary, the magnetic circuit compensation structure and the primary, and an air gap magnetic field at the end part of the primary is guided and reconstructed. According to the invention, the end magnetic field distortion and magnetic resistance are directly suppressed from the physical level, and the output stability, control precision and environmental adaptability of the motor are improved.

Description

Technical Field

[0001] This invention relates to the field of linear motor technology, and in particular to an end effect suppression device, design method, and cylindrical permanent magnet linear motor. Background Technology

[0002] Cylindrical permanent magnet linear motors, due to their advantages such as high thrust density, fast dynamic response, and compact structure, have been widely used in high-end equipment fields such as precision machining, semiconductor equipment, automated logistics, and high-speed rail transportation. However, due to their inherent open structure, the primary iron core of the motor inevitably experiences magnetic circuit breakage at both ends, resulting in significant end effects, which has become a key bottleneck restricting further performance improvements.

[0003] The end effect mainly manifests as asymmetric distortion and flux saturation of the air gap magnetic field at both ends of the primary stage, leading to two typical problems: First, the imbalance of the end magnetic field causes continuous end magnetic drag, which, together with the cogging force, constitutes the positioning force fluctuation, the main source of thrust pulsation. Second, during dynamic operation, the abrupt change in magnetic circuit coupling state when the mover (secondary) enters or exits the stator (primary) region results in back EMF waveform distortion, nonlinear thrust response, and severe fluctuations in normal force, seriously affecting the motor's control accuracy and operational stability. Existing research shows that the end force accounts for a large proportion of thrust fluctuation and is difficult to completely compensate for using conventional control strategies.

[0004] To suppress end-effects, existing technologies mainly address the issue from two levels: control algorithms and body structure. At the control level, strategies such as disturbance observers and sliding mode control are commonly used to estimate and compensate for end-effect disturbances in real time. However, these strategies still suffer from insufficient modeling accuracy for position-dependent disturbances and poor parameter robustness. At the body structure level, while some studies have proposed improving magnetic field distribution by optimizing primary segmentation, adding auxiliary slots, or employing complementary coil layouts, these methods are often complex to design, lack versatility, and are difficult to effectively transfer and scale up for use on cylindrical structures. Summary of the Invention

[0005] The purpose of this invention is to provide an end effect suppression device, design method, and cylindrical permanent magnet linear motor to solve the problems existing in the prior art, directly suppress end magnetic field distortion and magnetic resistance at the physical level, and improve the output stability, control accuracy, and environmental adaptability of the motor.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides an end-effect suppression device for a cylindrical permanent magnet linear motor, comprising a magnetic circuit compensation structure installed at at least one end of the primary stage of the motor; the magnetic circuit compensation structure consists of at least two concentric nested sleeves made of high magnetic permeability material, with an axial guiding mechanism between adjacent sleeve layers, allowing the inner sleeve to slide relative to the outer sleeve along the motor axial direction; the outermost sleeve is fixedly connected to the end of the primary stage, and the innermost sleeve is configured to maintain coupling with the secondary stage during motor operation, thereby forming a continuous magnetic circuit connection between the secondary stage, the magnetic circuit compensation structure, and the primary stage, to guide and reconstruct the air gap magnetic field at the end of the primary stage.

[0007] Preferably, the axial guiding mechanism includes a guide groove disposed on a first-layer sleeve and a guide ball disposed on an adjacent layer sleeve and cooperating with the guide groove.

[0008] Preferably, a mounting hole for accommodating the guide ball is provided on the sleeve with the guide ball; an elastic element is provided in the mounting hole, and the elastic element acts on the guide ball to press it into the guide groove of the adjacent sleeve layer.

[0009] Preferably, the elastic element is a disc spring; the mounting hole is a countersunk hole.

[0010] Preferably, the overall axial length and radial diameter of the magnetic circuit compensation structure, as well as the relevant dimensions of the guide mechanism and the elastic element, can be adjusted according to the stroke length and secondary diameter of the motor.

[0011] Preferably, the innermost sleeve is coupled to the secondary sleeve by magnetic attraction or fixed connection.

[0012] Preferably, it includes two magnetic circuit compensation structures installed at both ends of the primary of the motor.

[0013] The present invention also provides a cylindrical permanent magnet linear motor, including the end effect suppression device as described above.

[0014] This invention also provides a design method for an end-effect suppression device for a cylindrical permanent magnet linear motor. The suppression device includes a magnetic circuit compensation structure installed at at least one end of the motor primary. The magnetic circuit compensation structure consists of at least two concentrically nested sleeves made of a high-permeability material. An axial guide mechanism is provided between adjacent sleeve layers. The outermost sleeve is fixedly connected to the end of the primary, and the innermost sleeve is configured to maintain coupling with the motor secondary during movement. The design method includes the following steps: S1: Based on the primary end structure, secondary diameter, and air gap size of the target linear motor, determine the inner diameter of the innermost sleeve and the outer diameter of the outermost sleeve of the magnetic circuit compensation structure. S2: Based on the rated stroke of the target linear motor and the installation space constraints, determine the total axial length of the magnetic circuit compensation structure, the number of sleeve layers, and the axial sliding stroke of each sleeve layer; S3: Based on the number of sleeve layers and sliding stroke determined in step S2, design the specific form and spatial layout of the axial guide mechanism. The axial guide mechanism must ensure that the inner sleeve can slide smoothly along the axial direction relative to the outer sleeve. S4: Design the coupling method between the innermost sleeve and the motor secondary.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention provides a shortcut path for leaking magnetic field lines at the ends, with a magnetic reluctance far lower than that of air, using a high-permeability material. This actively guides and collects the originally disordered and dissipated magnetic flux. Secondly, through an axial guiding mechanism, the innermost sleeve can slide relative to the outermost sleeve fixed to the primary winding. This allows the innermost sleeve to maintain coupling with the secondary winding during motor operation, thus forming a continuous magnetic circuit connection between the secondary winding, the magnetic circuit compensation structure, and the primary winding. This guides and reconstructs the air gap magnetic field at the primary winding end, significantly reducing the end magnetic field distortion caused by magnetic circuit interruption. This fundamentally reduces end magnetic reluctance and the resulting thrust fluctuations, improving the stability and control accuracy of the motor output. Furthermore, because the secondary winding and part of the sleeve layer remain relatively stationary during movement, this greatly reduces eddy current losses caused by magnetic field lines cutting the sleeve material, reduces sleeve heating, and avoids mechanical wear that may occur due to relative sliding between the secondary winding and the sleeve, further improving the reliability and lifespan of the device. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of the cylindrical permanent magnet linear motor end effect suppression device provided in the embodiment of the present invention when applied to a linear motor; Figure 2 for Figure 1 In the middle, the schematic diagram of the magnetic circuit compensation structure on the left; Figure 3 for Figure 1 In the middle, the schematic diagram of the magnetic circuit compensation structure on the right; Figure 4 This is a structural diagram illustrating a sleeve with a countersunk hole spacing angle A1; Figure 5 This is a structural diagram illustrating a sleeve with a countersunk hole depth B and a countersunk hole diameter D; Figure 6 This is a structural diagram illustrating a sleeve with a guide groove spacing angle A2; Figure 7 This is a structural diagram illustrating a sleeve with a guide groove depth E and a guide groove length L; In the diagram: 1-Magnetic circuit compensation structure; 3-Primary stage; 4-Secondary stage; 5-Upper flange; 6-Lower flange; 106 - Guide ball; 107 - Elastic element; 121 - Guide groove; 101 - Outermost sleeve; 102 - Second sleeve; 103 - Third sleeve; 104 - Fourth sleeve; 105 - Fifth sleeve. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to provide an end effect suppression device, design method, and cylindrical permanent magnet linear motor to solve the problems existing in the prior art, directly suppress end magnetic field distortion and magnetic resistance at the physical level, and improve the output stability, control accuracy, and environmental adaptability of the motor.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0022] Example 1 This invention provides an end effect suppression device for a cylindrical permanent magnet linear motor, including a magnetic circuit compensation structure 1 installed at at least one end of the primary stage 3 of the motor. The magnetic circuit compensation structure 1 consists of at least two concentric nested sleeves made of high magnetic permeability material. An axial guiding mechanism is provided between adjacent sleeve layers, so that the inner sleeve can slide relative to the outer sleeve along the motor axial direction. The outermost sleeve 101 is fixedly connected to the end of the primary stage 3 (i.e., the stator), and the innermost sleeve is configured to maintain coupling with the secondary stage 4 during motor operation, thereby forming a continuous magnetic circuit connection between the secondary stage 4, the magnetic circuit compensation structure 1, and the primary stage 3, so as to guide and reconstruct the air gap magnetic field at the end of the primary stage.

[0023] This invention provides a magnetic circuit compensation structure 1 at the end of the primary motor 3, consisting of at least two concentrically nested high-permeability sleeves, with adjacent sleeves slidingly connected via an axial guiding mechanism. The beneficial effects of this invention can be derived as follows: First, the high-permeability material provides a shortcut path for leaking magnetic field lines at the end, much lower than the air magnetic resistance, actively guiding and collecting these originally disordered and dissipated magnetic fluxes. Second, through the axial guiding mechanism, the innermost sleeve can slide relative to the outermost sleeve 101 fixed to the primary motor 3. This allows the innermost sleeve to maintain coupling with the secondary motor during operation, thus forming a continuous magnetic circuit connection between the secondary motor, the magnetic circuit compensation structure, and the primary motor, guiding and reconstructing the air gap magnetic field at the end of the primary motor. Specifically, when the secondary motor 4 moves to the end region, the innermost sleeve undergoes axial displacement under magnetic force, maintaining a stable coupling state with the secondary motor 4. This mechanism ensures that the compensation magnetic circuit is continuously and stably effective throughout the entire motor operation, rather than only working at specific locations. Ultimately, the guided magnetic flux forms a new low-resistance loop through this compensation structure, which significantly reduces the end magnetic field distortion caused by the magnetic circuit interruption, fundamentally reducing the end magnetic resistance and the resulting thrust fluctuations, and improving the stability of motor output and control accuracy.

[0024] In addition, during the movement of secondary 4, it remains stationary with part of the sleeve, which reduces the current generated by the magnetic field lines cutting the sleeve, reduces the heat generation of the sleeve, and avoids wear caused by the sliding contact between secondary 4 and the sleeve.

[0025] It should be noted that, Figure 2 and Figure 3 The diagram illustrates the structure of two magnetic circuit compensation structures 1 with different numbers of layers. Figure 2 In the middle, the fourth sleeve 104 is the innermost sleeve; in Figure 3 In the middle, the fifth sleeve 105 is the innermost sleeve.

[0026] In some embodiments, in any two adjacent sleeves, the outer wall of the inner sleeve and the inner wall of the outer sleeve are in close contact.

[0027] In some embodiments, the axial guiding mechanism includes a guide groove 121 disposed on a layer sleeve and a guide ball 106 disposed on an adjacent layer sleeve and cooperating with the guide groove 121.

[0028] Understandably, the length of the guide groove 121 limits the relative sliding distance between two adjacent sleeves.

[0029] This embodiment, based on the above embodiments, further specifies the axial guiding mechanism as a combination of "guide groove 121 and guide ball 106". Its advantages are as follows: First, the point contact or short-segment contact between the ball and the groove results in low frictional resistance, ensuring smooth sliding and responsiveness between the sleeve layers, which is crucial for dynamic compensation of high-frequency, high-speed linear motors. Second, the guide groove 121 precisely constrains the movement trajectory of the guide ball 106, strictly limiting the relative movement between the sleeves to the motor axial direction, effectively preventing radial offset or circumferential rotation between layers. This ensures the coaxiality and motion stability of the multi-layer compensation structure under complex electromagnetic forces and mechanical vibrations, thereby ensuring the reliability and consistency of the magnetic circuit compensation effect.

[0030] The axial guiding mechanism can also employ other forms of sliding pairs. For example, mating axial keys and keyways can be directly machined onto the mating surfaces of adjacent sleeves, or a miniature linear guide slider can be installed on the sleeve end face using the principle of linear guide slider miniaturization. These alternative solutions can also achieve the basic function of axial guidance, but each has its own characteristics in terms of friction characteristics, load-bearing capacity, or space occupation.

[0031] Alternatively, the axial sliding of the two sleeves can be achieved by directly utilizing the contact between the outer wall of the inner sleeve and the inner wall of the outer sleeve.

[0032] In some embodiments, a mounting hole for accommodating the guide ball 106 is provided on the sleeve. An elastic element 107 is disposed in the mounting hole, and the elastic element 107 acts on the guide ball 106 to press it into the guide groove 121 of the adjacent sleeve layer. The elastic element 107 is preferably a disc spring; the mounting hole is preferably a countersunk hole.

[0033] This embodiment, based on the above embodiment, adds the feature of an elastic element 107 (such as a disc spring) pressing the guide ball 106. Its beneficial effects are derived as follows: During motor operation, especially during startup, braking, or impact, each sleeve layer is subjected to changing electromagnetic and inertial forces, which may cause momentary disengagement or impact collisions between the guide ball 106 and the guide groove 121, generating noise and affecting positional accuracy. By continuously applying a pressing force to the guide ball 106 with the elastic element 107, the mechanical clearance in the guide pair can be eliminated at all times, maintaining a stable contact state between the guide ball 106 and the guide groove 121. This is equivalent to providing a "preload" for the entire sliding multi-layer structure, enhancing its dynamic stiffness, ensuring that even under varying operating conditions, each sleeve layer can still function as a whole, avoiding sudden changes in the compensating magnetic field or mechanical noise caused by loosening, and improving the reliability and environmental adaptability of the device.

[0034] The method of providing clamping force is not limited to setting a disc spring in the mounting hole. For example, a pad made of elastic material (such as silicone or polyurethane) can be set on the side of the guide ball 106 opposite to the guide groove 121; or, the mounting hole itself can be designed as an elastic contraction structure, relying on the elasticity of the material to clamp the guide ball 106 and provide radial preload.

[0035] In some embodiments, the overall axial length, radial diameter, and related dimensions of the guide mechanism and elastic element 107 of the magnetic circuit compensation structure 1 can be adjusted according to the stroke length of the motor and the diameter of the secondary 4.

[0036] In this embodiment, linear motors with different power, stroke, and secondary diameter exhibit varying degrees of magnetic field distortion and required flux compensation at their ends. By designing the suppression device as a modular structure with adjustable parameters, it can be quickly adapted to various motor models simply by replacing a sleeve of a specific size or adjusting the parameters of the guide / preload components. This solves the problems of poor versatility and high customization costs associated with traditional end suppression solutions, achieving "one design principle for multiple product adaptations," significantly enhancing the engineering application value and market potential of this technology.

[0037] In some embodiments, the innermost sleeve is coupled to the secondary 4 by magnetic attraction or fixed connection.

[0038] In this embodiment, if magnetic attraction is used, a permanent magnet for attracting the innermost sleeve can be additionally installed at a corresponding position on secondary stage 4. Alternatively, the magnetic field of the permanent magnet inherent in secondary stage 4 can be used to attract the innermost sleeve. This is a passive, adaptive, and contactless coupling. It can automatically establish and maintain an optimal micro-air gap, ensuring unobstructed magnetic circuitry while avoiding mechanical friction. If a mechanical fixed connection is used (such as through detachable connecting rods, clamps, bolts, or screws), rigid synchronous movement between the innermost sleeve and secondary stage 4 can be achieved, ensuring absolute relative stillness, suitable for applications requiring extremely high compensation stability. These two methods provide users with choices based on different precision and cost requirements.

[0039] In some linear motors, when one end of the secondary 4 is in an extreme position, that end has an end cap that is completely inserted into the primary 3. Therefore, it is not possible to connect the innermost sleeve and the secondary 4 by means of a fixed connection. Instead, magnetic attraction is required for the connection. Based on this, a permanent magnet is fixedly installed on the end cap. The permanent magnet is preferably annular, and the groove of the end cap is also annular. The permanent magnet is installed in the annular groove, and the innermost sleeve is attracted by the permanent magnet embedded in the end cap.

[0040] If the end of secondary 4 protrudes from primary 3 when it is in one of the two extreme positions, screws or bolts can be used to fix the two together.

[0041] Of course, on the same linear motor, both ends can be magnetically attracted or fixedly connected, or one end can be magnetically attracted and the other end fixed. This needs to be designed according to the specific structure of the linear motor.

[0042] In some embodiments, the end effect suppression device for the cylindrical permanent magnet linear motor includes two magnetic circuit compensation structures 1 installed at both ends of the primary motor 3.

[0043] This embodiment clarifies that the suppression devices are symmetrically installed at both ends of the primary 3 of the motor. The beneficial effects are obvious: both ends of the primary 3 of the cylindrical linear motor exhibit magnetic circuit interruption and end effects. Installing suppression devices simultaneously at both ends allows for synchronous compensation and reconstruction of the magnetic fields at both ends of the primary 3, ensuring a smooth thrust transition throughout the entire stroke, whether moving forward or backward, when entering or exiting the end regions. This achieves performance improvement across the entire stroke range and eliminates the asymmetry problems that may result from single-end suppression.

[0044] In certain specific applications (such as unidirectional operation, extremely short stroke, or structural limitations), the suppression device may be installed only at one end of the primary motor 3 to address the most prominent disturbance problem at that particular end.

[0045] In some embodiments, such as Figure 1 As shown, the outermost sleeve 101 of the magnetic circuit compensation structure 1 on the left is installed on the outer shell of the primary 3 through the upper flange 5, specifically by clamping and fixing the upper flange 5 and the outer shell; while due to space constraints, the outermost sleeve 101 of the magnetic circuit compensation structure 1 on the right can be fixed to the lower flange 6 by bonding, and the lower flange 6 and the outer shell of the primary 3 are fixedly connected and in contact.

[0046] Example 2 This invention also provides a design method for an end-effect suppression device for a cylindrical permanent magnet linear motor. The suppression device includes a magnetic circuit compensation structure 1 installed at at least one end of the primary motor 3. The magnetic circuit compensation structure 1 consists of at least two concentric nested sleeves made of high magnetic permeability material. An axial guide mechanism is provided between adjacent sleeve layers. The outermost sleeve 101 is fixedly connected to the end of the primary motor 3, and the innermost sleeve is configured to maintain coupling with the secondary motor 4 during movement. The design method includes the following steps: S1: Based on the primary 3 end structure, secondary 4 diameter and air gap size of the target linear motor, determine the inner diameter of the innermost sleeve and the outer diameter of the outermost sleeve 101 of the magnetic circuit compensation structure 1. S2: Based on the rated stroke of the target linear motor and the installation space constraints, determine the total axial length, the number of sleeve layers, and the axial sliding stroke of each sleeve layer of the magnetic circuit compensation structure 1. S3: Based on the number of sleeve layers and sliding stroke determined in step S2, design the specific form and spatial layout of the axial guide mechanism. The axial guide mechanism must ensure that the inner sleeve can slide smoothly along the axial direction relative to the outer sleeve. S4: Design the coupling method between the innermost sleeve and the secondary winding of the motor 4.

[0047] This embodiment provides a design method for the end effect suppression device in Embodiment 1, applicable to linear motors with different strokes and specifications.

[0048] More specifically, the main parameters of the countersunk hole include A1 - countersunk hole spacing angle, B - countersunk hole depth, and D - countersunk hole diameter; the main parameters of the guide groove 121 include A2 - guide groove 121 spacing angle, E - guide groove 121 depth, and L - guide groove 121 length. By combining these parameters, the preload provided by the disc spring can be precisely controlled to adapt to the stroke of linear motors of different specifications.

[0049] Example 3 The present invention also provides a cylindrical permanent magnet linear motor, including the end effect suppression device in Embodiment 1. Preferably, magnetic circuit compensation structures are provided at both ends of its primary stage.

[0050] This embodiment provides a cylindrical permanent magnet linear motor that integrates the end-effect suppression device described in any of the above embodiments. Its advantages are: the motor integrates an innovative end-effect suppression device into its body, directly improving its electromagnetic performance at the physical structure level. Compared to motors that rely on external control algorithms for compensation, it reduces the complexity of the control system and the difficulty of parameter tuning; compared to similar motors without suppression devices, it has significant advantages in key performance indicators such as thrust fluctuation, speed stability, and positioning accuracy, becoming a high-performance, high-reliability direct-drive component.

[0051] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A device for suppressing end-effects of a cylindrical permanent magnet linear motor, characterized in that: The device includes a magnetic circuit compensation structure installed at at least one end of the primary motor. The magnetic circuit compensation structure consists of at least two concentric nested sleeves made of high magnetic permeability material. An axial guide mechanism is provided between adjacent sleeve layers, allowing the inner sleeve to slide relative to the outer sleeve along the motor axial direction. The outermost sleeve is fixedly connected to the end of the primary motor, and the innermost sleeve is configured to maintain coupling with the secondary motor during motor operation. This creates a continuous magnetic circuit connection between the secondary motor, the magnetic circuit compensation structure, and the primary motor, thereby guiding and reconstructing the air gap magnetic field at the end of the primary motor.

2. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 1, characterized in that: The axial guiding mechanism includes a guide groove disposed on a first-layer sleeve and a guide ball disposed on an adjacent layer sleeve and cooperating with the guide groove.

3. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 2, characterized in that: A mounting hole for accommodating the guide ball is provided on the sleeve with the guide ball; an elastic element is provided in the mounting hole, and the elastic element acts on the guide ball to press it into the guide groove of the adjacent sleeve layer.

4. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 3, characterized in that: The elastic element is a disc spring; the mounting hole is a countersunk hole.

5. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 3, characterized in that: The overall axial length and radial diameter of the magnetic circuit compensation structure, as well as the relevant dimensions of the guide mechanism and elastic element, can be adjusted according to the stroke length and secondary diameter of the motor.

6. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 1, characterized in that: The innermost sleeve is coupled to the secondary sleeve by magnetic attraction or fixed connection.

7. The end effect suppression device for a cylindrical permanent magnet linear motor according to claim 1, characterized in that: It includes two magnetic circuit compensation structures installed at both ends of the primary motor.

8. A design method for an end-effect suppression device for a cylindrical permanent magnet linear motor according to any one of claims 1 to 7, characterized in that, include: S1: Based on the primary end structure, secondary diameter, and air gap size of the target linear motor, determine the inner diameter of the innermost sleeve and the outer diameter of the outermost sleeve of the magnetic circuit compensation structure. S2: Based on the rated stroke of the target linear motor and the installation space constraints, determine the total axial length of the magnetic circuit compensation structure, the number of sleeve layers, and the axial sliding stroke of each sleeve layer; S3: Based on the number of sleeve layers and sliding stroke determined in step S2, design the specific form and spatial layout of the axial guide mechanism. The axial guide mechanism must ensure that the inner sleeve can slide smoothly along the axial direction relative to the outer sleeve. S4: Design the coupling method between the innermost sleeve and the motor secondary.

9. A cylindrical permanent magnet linear motor, characterized in that: Includes the end effect suppression device as described in any one of claims 1 to 7.

10. The cylindrical permanent magnet linear motor according to claim 9, characterized in that: Both ends of its primary stage are equipped with magnetic circuit compensation structures.

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