Rotary and linear composite motion linear motor and control method thereof

Abstract

The invention provides a linear motor capable of rotating and linear composite motion and a control method thereof, the motor comprises a stator, the stator is provided with stator slots in two different directions, the stator slots comprise stator left-hand spiral slots and stator right-hand spiral slots, left-hand coils and right-hand coils are respectively embedded in the stator left-hand spiral slots and the stator right-hand spiral slots, and the left-hand coils and the right-hand coils are respectively embedded in the stator left-hand spiral slots and the stator right-hand spiral slots. The left-handed coil and the right-handed coil respectively form a left-handed winding and a right-handed winding, and the left-handed winding and the right-handed winding are respectively controlled by independent current controllers; the mover is provided with at least two types of mover grooves; the auxiliary mechanism is used for keeping the concentricity between the stator and the rotor and keeping a uniform air gap between the stator and the rotor; wherein the stator is arranged to be an outer stator, and the rotor is sleeved with the outer stator; or, the stator is arranged to be an inner stator, and the rotor is arranged outside the stator in a sleeving mode. The invention solves the technical problems of low precision, difficult synchronization, large loss and large size of a separated driving scheme of traditional equipment, and belongs to the technical field of motors.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a linear motor and its control method for rotary-linear composite motion. Background Technology

[0002] In the field of gas compression, "rotational + linear" compound motion is frequently required. In traditional equipment, this compound motion is driven separately by independent motors, achieved through a combination of intermediate transmission mechanisms such as a rotary motor, a linear motor, and gears / lead screws / couplings. Furthermore, synchronization requires a complex control system (such as a PLC or motion controller). Therefore, the traditional separate drive scheme presents several problems in its application. First, the synchronization accuracy is low. Due to differences in motor response characteristics and transmission chain delays, it is difficult to achieve high-precision trajectory matching.

[0003] Secondly, energy loss is significant. Each of the multiple motors has its own copper and iron losses, and friction in the intermediate transmission components further consumes energy, resulting in a low system energy efficiency ratio.

[0004] Third, the equipment is bulky. In some scenarios with stringent requirements on size and weight, such as bionic robot joints, missile seeker head drives, and semiconductor wafer handling, traditional equipment is difficult to adapt due to its large size and weight.

[0005] Based on the above-mentioned technical problems, this invention has developed a linear motor for rotary-linear composite motion and its control method. Summary of the Invention

[0006] The purpose of this invention is to provide a linear motor for rotary-linear composite motion and its control method, aiming to solve the technical problems of low precision, difficulty in synchronization, high loss and large size of traditional equipment with separate drive schemes.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a linear motor for rotary-linear composite motion, comprising: The stator has two types of stator slots with different orientations, including a left-hand helical slot and a right-hand helical slot. A left-hand coil and a right-hand coil are respectively embedded in the left-hand helical slot and the right-hand helical slot. The left-hand coil and the right-hand coil form a left-hand winding and a right-hand winding, respectively. The left-hand winding and the right-hand winding are controlled by independent current controllers. A mover, wherein at least two types of mover slots are provided on the mover; An auxiliary mechanism is used to maintain the concentricity between the stator and the mover and to maintain a uniform air gap between them. The stator is configured as an outer stator, which is sleeved on the outside of the mover; Alternatively, the stator may be configured as an inner stator, with the mover sleeved outside the stator.

[0008] In one embodiment, the machine base, end caps, and drive shaft are also included. The end caps are disposed at both ends of the machine base, and the drive shaft is disposed inside the machine base and passes through the end caps and extends to the outside of the end caps. When the stator is configured as an external stator, the stator is disposed on the inner wall of the machine base, the mover is disposed on the outer wall of the transmission shaft, and the mover is installed inside the stator through the cooperation of the auxiliary mechanism; When the stator is configured as an inner stator, the stator is fixed inside the machine base by a fixing mechanism, the mover is sleeved outside the stator by the auxiliary mechanism, and the drive shaft is mounted on the mover.

[0009] In one embodiment, when the stator is configured as an external stator, the auxiliary mechanism is an external structure, including a first composite bearing, which is disposed on the end cover. The outer wall of the drive shaft contacts the inner wall of the first composite bearing, and the drive shaft is rotatably and slidably connected to the end cover through the first composite bearing. Alternatively, the auxiliary mechanism is a built-in structure, including a second composite bearing, which is disposed on the inner walls of both ends of the stator. The outer wall of the mover is in contact with the inner wall of the second composite bearing. The mover and the drive shaft are rotatably and slidably connected to the end cover through the second composite bearing.

[0010] In one embodiment, when the stator is configured as an inner stator, the auxiliary mechanism is an internal structure, including a third composite bearing. The third composite bearing is disposed on the inner walls of both ends of the mover, and the outer wall of the stator is in contact with the inner wall of the third composite bearing. The mover and the transmission shaft are rotatably and slidably connected to the end cover through the third composite bearing. Alternatively, the auxiliary mechanism may be a built-in structure, including a fourth composite bearing, which is disposed on the inner wall of the base. The outer wall of the mover is in contact with the inner wall of the fourth composite bearing. The mover and the transmission shaft are rotatably and slidably connected to the end cover through the fourth composite bearing.

[0011] In one embodiment, the stator and the mover are configured in a columnar or stepped shape.

[0012] In one embodiment, the number of both the left-hand coil and the right-hand coil is three or more, forming a three-phase or more multi-phase left-hand winding and a multi-phase right-hand winding, respectively. Alternatively, there may be two left-hand coils and two right-hand coils, forming two-phase left-hand windings and two-phase right-hand windings respectively; Alternatively, the total number of the left-hand coil and the right-hand coil is less than four, and it also includes several permanent magnets, which are circumferentially spaced on the mover or in the mover slot.

[0013] In one embodiment, the left-hand coil and the right-hand coil are spatially intersecting, partially intersecting, or not intersecting at all.

[0014] In one embodiment, the mover slot includes a left-handed movingr helical slot and a right-handed movingr helical slot, wherein the left-handed movingr helical slot matches the left-handed stator helical slot, and the right-handed movingr helical slot matches the right-handed stator helical slot; Alternatively, the moving part slot may include a first moving part helical slot and a second moving part helical slot, wherein the pitches of the first moving part helical slot and the second moving part helical slot are different; Alternatively, the moving part groove includes a straight groove and an annular groove, wherein the straight groove is parallel to the axis of the moving part and the annular groove is perpendicular to the axis of the moving part.

[0015] The present invention also provides a control method for a linear motor of rotary-linear composite motion as described in any of the above claims, comprising the following steps: By applying current to the left-hand and right-hand coils respectively through independent current controllers, and by adjusting the direction and intensity of the current in the left-hand and right-hand coils, the mover can be driven to perform pure linear motion, pure rotational motion, or a combination of rotation and linear motion.

[0016] In one embodiment, the method for synthesizing pure linear motion is as follows: the rotational components generated by the left-hand coil and the right-hand coil are controlled to be equal in magnitude and opposite in direction to cancel each other out, and the linear components generated by them are controlled to be equal in magnitude and same in direction to be superimposed, thereby driving the mover to perform pure linear motion along the axis. The method for synthesizing pure rotational motion is as follows: control the linear components of the left-hand and right-hand coils to be equal in magnitude and opposite in direction so as to cancel each other out, and control the rotational components of the coils to be equal in magnitude and same in direction so as to superimpose them, thereby driving the mover to perform pure rotational motion around the axis; The method for synthesizing the combined rotational and linear motion is as follows: control the linear components generated by the left-hand and right-hand coils to be equal in magnitude and in the same direction so as to superimpose them, and control the rotational components generated by them to be equal in magnitude and in the same direction so as to superimpose them, thereby driving the mover to perform a combined rotational and linear motion along the axis of "rotating and extending".

[0017] This invention provides a linear motor for rotary-linear composite motion and its control method. Compared with the prior art, its advantages are: (1) The present invention sets stator left-hand spiral groove and stator right-hand spiral groove with opposite spiral directions on the stator. Left-hand coil and right-hand coil are respectively embedded in the stator left-hand spiral groove and stator right-hand spiral groove. The left-hand coil and right-hand coil are controlled by independent current controllers. In use, current is applied to the left-hand coil and right-hand coil respectively through independent current controllers. By adjusting the current direction and intensity of the left-hand coil and right-hand coil, the mover is driven to perform pure linear motion, pure rotational motion or rotational-linear combined motion, thereby realizing the decoupling and combined control of the two degrees of freedom of linear and rotation.

[0018] (2) This invention uses direct electromagnetic drive, eliminating all intermediate transmission components such as "rotary motor + linear motor + gear / lead screw / coupling", simplifying the mechanical structure and eliminating transmission gaps and elastic deformations such as gear meshing clearance and lead screw pitch error. This improves motion accuracy from the millimeter level of traditional equipment to the micrometer level, making it particularly suitable for high-speed precision operations. It also reduces mechanical friction loss and lowers maintenance costs caused by component wear. In addition, this invention uses independent current controllers to adjust the current direction and intensity of the left-hand and right-hand coils respectively, enabling real-time synthesis of arbitrary ratio rotary-linear composite motion without switching mechanical structures, resulting in higher motion control flexibility and adaptability to complex working conditions. Furthermore, this invention integrates two driving functions into the same magnetic circuit system, a unified design that simplifies the mechanical structure and significantly reduces the size of the equipment, making it particularly suitable for multi-dimensional driving scenarios in confined spaces. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the stator and mover of a linear motor for rotary-linear composite motion according to an embodiment of this application (the stator is an external stator); Figure 2 for Figure 1 The diagram shows the structure of the stator of a linear motor that performs a combined rotary-linear motion (the stator is an external stator). Figure 3 for Figure 1 The stator of the linear motor that performs a combined rotary-linear motion is shown in the figure (the stator is an external stator). Figure 4 for Figure 1The diagram shows a cross-sectional view of the stator and coils of a linear motor that performs a combined rotary-linear motion (the stator is an outer stator, and there is one left-handed coil and one right-handed coil). Figure 5 for Figure 1 The diagram shows a cross-sectional view of the stator and coils of a linear motor that performs a combined rotary-linear motion (the stator is an outer stator, and there are two or more left-hand and right-hand coils). Figure 6 for Figure 1 The diagram shows the structure of the mover of a linear motor that performs a combined rotary-linear motion (the stator is an outer stator, and the mover slots are left-hand spiral slots and right-hand spiral slots). Figure 7 for Figure 1 The diagram shows the structure of the mover of a linear motor that performs a combined rotary-linear motion (the stator is an outer stator, and the mover slots are the first mover helical slot and the second mover helical slot). Figure 8 for Figure 1 The diagram shows the structure of the mover of a linear motor that performs a combined rotary-linear motion (the stator is an outer stator, and the mover slots are straight slots and annular slots). Figure 9 A schematic diagram of the stator and mover of a linear motor for rotary-linear composite motion according to an embodiment of this application (the stator is an inner stator); Figure 10 for Figure 9 The diagram shows the structure of the stator of a linear motor that performs a combined rotary-linear motion (the stator is an inner stator). Figure 11 for Figure 9 The diagram shows the main structural view of the stator of a linear motor that performs a combined rotary and linear motion (the stator is an inner stator). Figure 12 for Figure 9 The diagram shows the structure of the mover (the stator is an inner stator) of a linear motor that performs a combined rotary-linear motion. Figure 13 for Figure 9 The diagram shows a cross-sectional view of the mover of a linear motor that performs a combined rotary and linear motion (the stator is an inner stator). Figure 14 for Figure 9 The diagram shows the main view of the moving part slot of the linear motor that performs rotary-linear compound motion (the stator is an inner stator, and the moving part slot consists of a left-hand helical slot and a right-hand helical slot). Figure 15 for Figure 9 The diagram shows the main view of the moving part slot of a linear motor that performs a combined rotary-linear motion (the stator is an inner stator, and the moving part slots are the first moving part helical slot and the second moving part helical slot). Figure 16 for Figure 9 The diagram shows the main view of the moving slot of a linear motor that performs a combined rotary and linear motion (the stator is an inner stator, and the moving slot consists of a straight slot and an annular slot).

[0021] Explanation of symbols in the diagram: 1. Stator; 2. Movable element; 3. Stator slots; 301. Stator left-hand spiral slots; 302. Stator right-hand spiral slots; 4. Moving element groove; 401. Moving element left-hand spiral groove; 402. Moving element right-hand spiral groove; 403. First moving element spiral groove; 404. Second moving element spiral groove; 405. Straight groove; 406. Annular groove; 5. Left-handed coil; 6. Right-hand coil. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed" or "set" to another component, it can be directly or indirectly attached to that other component. When a component is referred to as being "connected" to another component, it can be directly or indirectly connected to that other component.

[0024] It should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and should not be construed as indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] (a) Linear motors with combined rotary and linear motion Please see Figure 1 This is a schematic diagram of the stator and mover of a linear motor for rotary-linear composite motion according to an embodiment of this application (the stator is an external stator). For ease of explanation, only the parts relevant to this embodiment are shown, and are described in detail below: In one embodiment, please refer to Figures 2-16A linear motor for rotary-linear composite motion includes a stator 1, a mover 2, and an auxiliary mechanism. The stator 1 has two stator slots 3 with different orientations. The stator slots 3 include a left-hand helical slot 301 and a right-hand helical slot 302. A left-hand coil 5 and a right-hand coil 6 are respectively embedded in the left-hand helical slot 301 and the right-hand helical slot 302. The left-hand coil 5 and the right-hand coil 6 form a left-hand winding and a right-hand winding, respectively. The left-hand winding and the right-hand winding are controlled by independent current controllers. The mover 2 has at least two types of mover slots 4. The auxiliary mechanism is used to maintain the concentricity between the stator 1 and the mover 2 and to maintain a uniform air gap between them. The stator 1 is configured as an outer stator, which is sleeved on the outside of the mover 2; or, the stator 1 is configured as an inner stator, and the mover 2 is sleeved on the outside of the stator 1.

[0026] This invention achieves decoupling and composite control of the two degrees of freedom of linear and rotation by setting a left-hand spiral groove 301 and a right-hand spiral groove 302 with opposite spiral directions on the stator 1. A left-hand coil 5 and a right-hand coil 6 are respectively embedded in the left-hand spiral groove 301 and the right-hand spiral groove 302. The left-hand coil 5 and the right-hand coil 6 are controlled by independent current controllers. In use, current is applied to the left-hand coil 5 and the right-hand coil 6 through the independent current controllers. By adjusting the current direction and intensity of the left-hand coil 5 and the right-hand coil 6, the mover 2 is driven to perform pure linear motion, pure rotational motion, or a combination of rotation and linear motion, thus realizing the decoupling and composite control of the two degrees of freedom of linear and rotation.

[0027] This invention utilizes direct electromagnetic drive, eliminating all intermediate transmission components such as rotary motors, linear motors, gears / lead screws / couplings, etc., simplifying the mechanical structure and eliminating transmission gaps and elastic deformations such as gear meshing backlash and lead screw pitch errors. This improves motion accuracy from millimeters to micrometers, making it particularly suitable for high-speed precision operations. It also reduces mechanical friction losses, lowering maintenance costs due to component wear. Furthermore, this invention uses independent current controllers to adjust the current direction and intensity of the left-hand coil 5 and the right-hand coil 6, enabling real-time synthesis of arbitrary ratio rotary-linear composite motion without switching mechanical structures, resulting in greater motion control flexibility and adaptability to complex working conditions. Moreover, this invention integrates two driving functions into a single magnetic circuit system, a unified design that simplifies the mechanical structure and significantly reduces the equipment size, making it particularly suitable for multi-dimensional driving scenarios in confined spaces.

[0028] Specifically, the linear motor also includes a base, end covers, and a drive shaft; the end covers are located at both ends of the base, and the drive shaft is located inside the base and passes through the end covers and extends to the outside of the end covers.

[0029] When stator 1 is configured as an external stator, it is mounted on the inner wall of the machine base, and mover 2 is mounted on the outer wall of the drive shaft. Mover 2 is installed inside stator 1 through an auxiliary mechanism. In this configuration, stator 1 is rigidly connected to the machine base; mover 2 is fitted onto the middle section of the drive shaft and fixedly connected to it; both ends of the drive shaft pass through end covers and extend to the outside of the end covers, connecting to an external load. When left-hand coil 5 and right-hand coil 6 are energized, a composite electromagnetic field is generated. This composite electromagnetic field interacts with mover 2, generating an electromagnetic force that drives mover 2 to move. The motion of mover 2 is directly transmitted to the drive shaft, which then outputs the composite motion to the external load.

[0030] When stator 1 is configured as an inner stator, it is fixed inside the machine base via a fixing mechanism, and mover 2 is sleeved outside stator 1 via an auxiliary mechanism. A drive shaft is mounted on mover 2. At this time, end covers are located at both ends of the machine base, and the drive shaft passes through the end covers and extends to the outside of the end covers. Stator 1 is rigidly connected to the machine base via the fixing mechanism; one end of the drive shaft passes through the end covers and extends to the outside of the end covers, connecting to an external load. When left-hand coil 5 and right-hand coil 6 are energized, a composite electromagnetic field is generated. This composite electromagnetic field interacts with mover 2, generating an electromagnetic force that drives mover 2 to move. The movement of mover 2 is directly transmitted to the drive shaft, which outputs the composite motion to the external load.

[0031] Compared to the "stator outside, mover inside" structure, the "motor outside, stator inside" structure allows for a larger effective radius of motion for the mover 2, resulting in greater torque and linear thrust under the same electromagnetic force. Furthermore, the inner stator design brings the heat-generating stator 1 closer to the stationary component at the center of the motor, enabling the design of more efficient cooling channels to directly cool the heat source. Additionally, the large surface area of ​​the outer mover is exposed to the environment or cooling medium, helping to dissipate heat generated by eddy currents and other factors, preventing motor damage or performance degradation due to overheating.

[0032] In one embodiment, when the stator 1 is configured as an external stator, the auxiliary mechanism is an external structure, including a first composite bearing (not shown in the figure). The first composite bearing is mounted on the end cover, and the outer wall of the drive shaft contacts the inner wall of the first composite bearing. The drive shaft is rotatably and slidably connected to the end cover through the first composite bearing. The first composite bearing can be a linear-rotational composite bearing, such as a "ball spline bearing," with a built-in spline shaft and spline sleeve. The spline structure transmits rotational torque to achieve rotational motion, while the ball circulation structure guides axial linear motion, allowing it to simultaneously bear rotational and linear composite motion. The first composite bearing can also be a combination of a linear bearing and a deep groove ball bearing (or angular contact ball bearing). The linear bearing undertakes linear motion, and the deep groove ball bearing (or angular contact ball bearing) undertakes rotational motion. The two are connected in series through a bushing or flange, each responsible for a single motion, avoiding mutual interference. The outer ring of the first composite bearing is interference-fitted with the bearing bore on the end cover, and the inner ring of the bearing is connected to the drive shaft by a spline or flat key. This allows the drive shaft to slide axially for linear motion and transmit torque for rotational motion, while also having radial rigidity to limit the radial wobble of the drive shaft.

[0033] In one embodiment, when the stator 1 is configured as an external stator, the auxiliary mechanism is an internal structure, including a second composite bearing (not shown in the figure). The second composite bearing is disposed on the inner walls of both ends of the stator 1, and the outer wall of the mover 2 is in contact with the inner wall of the second composite bearing. The mover 2 and the drive shaft are rotatably and slidably connected to the end cover through the second composite bearing. The second composite bearing can be a deep groove ball bearing with an axial sliding groove. The outer ring of the bearing is fixed to the inner wall of the stator 1, and the inner ring of the bearing is fixedly connected to the outer wall of the mover 2, allowing the drive shaft to perform linear and rotary motion.

[0034] In one embodiment, when the stator 1 is configured as an inner stator, the auxiliary mechanism is an internal structure, including a third composite bearing (not shown in the figure). The third composite bearing is disposed on the inner walls of both ends of the mover 2, and the outer wall of the stator 1 contacts the inner wall of the third composite bearing. The mover 2 and the drive shaft are rotatably and slidably connected to the end cover through the third composite bearing. The third composite bearing can be a ball spline bearing, a linear rotary bearing, or a deep groove ball bearing with an axial sliding groove, possessing the ability to "simultaneously bear rotational motion and linear motion," allowing the mover 2 and the drive shaft to perform linear and rotational motion. The third composite bearing is built inside the mover 2, and the force point is closer to the center of gravity plane of the mover 2, which can reduce the overturning moment during composite motion, especially when high-speed rotation and high-frequency linear motion are superimposed, effectively suppressing the yaw and vibration of the mover 2.

[0035] In one embodiment, when the stator 1 is configured as an inner stator, the auxiliary mechanism is an internal structure, including a fourth composite bearing (not shown in the figure). The fourth composite bearing is disposed on the inner wall of the machine base, and the outer wall of the mover 2 contacts the inner wall of the fourth composite bearing. The mover 2 and the drive shaft are rotatably and slidably connected to the end cover through the fourth composite bearing. The fourth composite bearing can be a ball spline bearing, a linear rotary bearing, or a deep groove ball bearing with axial sliding grooves, possessing the ability to "simultaneously bear rotational motion and linear motion," allowing the mover 2 and the drive shaft to perform linear and rotational motion. Because the fourth composite bearing is disposed on the inner wall of the machine base, its contact radius with the mover 2 is larger, resulting in lower contact pressure under the same load, and enabling it to withstand higher rotational speeds and greater linear thrust.

[0036] The auxiliary mechanism ensures that the mover 2 remains concentric with the stator 1 during rotational and linear motion, and maintains a uniform air gap with the stator 1, enabling the motor to operate efficiently and smoothly.

[0037] In one embodiment, please refer to Figures 1-8 The stator 1 and the mover 2 are shaped like columns. The left-hand coil 5 and the right-hand coil 6 of the columnar stator 1 can be evenly distributed along the circumference. Combined with the uniform slot shape of the columnar mover 2, the air gap magnetic field is more evenly distributed along the axial and circumferential directions, reducing thrust pulsation caused by magnetic flux fluctuations and ensuring stable linear thrust.

[0038] In one embodiment, please refer to Figures 9-13 The stator 1 and mover 2 are designed in a stepped shape. This stepped shape allows for segmented optimization of the magnetic circuit and thrust. In the large-diameter section, the number of helical grooves is increased to enhance electromagnetic thrust and adapt to high-pressure compression strokes. In the small-diameter section, the number of coils is reduced to lower no-load losses and adapt to low-pressure intake strokes. The stepped design improves the motor's energy efficiency throughout the entire compression cycle.

[0039] In one embodiment, please refer to Figures 3-5 and Figures 9-11 The number of left-hand coil 5 and right-hand coil 6 are three or more, forming a three-phase or more multi-phase left-hand winding and a multi-phase right-hand winding, respectively. The more phases, the closer the magnetic field waveform generated by the left-hand coil 5 and the right-hand coil 6 is to a sine wave, with less harmonic content, resulting in smoother motor operation, lower noise, and less torque ripple.

[0040] In one embodiment, please refer to Figures 3-5 and Figures 9-11There are two left-hand coils 5 and two right-hand coils 6, forming two-phase left-hand windings and two-phase right-hand windings respectively. When there are two left-hand coils 5 and two right-hand coils 6, a traveling wave magnetic field can be generated by passing two-phase alternating current with a phase difference of 90 degrees to both the two-phase left-hand windings and the two-phase right-hand windings.

[0041] When there are two or more left-hand coils 5 and right-hand coils 6, the left-hand coils 5 and right-hand coils 6 form a symmetrical rotating magnetic field and an axial magnetic field through the combination of current, ensuring that the mover 2 can be subjected to a clear starting force at any initial position and that there will be no "starting dead zone".

[0042] In one embodiment, please refer to Figures 3-5 and Figures 9-11 The total number of left-hand coils 5 and right-hand coils 6 is less than four, and it also includes several permanent magnets, which are circumferentially spaced on the mover 2 or in the mover slot 4. When the total number of left-hand coils 5 and right-hand coils 6 is less than four, the electromagnetic field distribution generated by the left-hand coils 5 and right-hand coils 6 is asymmetrical. The electromagnetic forces experienced by the mover 2 at certain initial positions cancel each other out or become disordered, making it impossible to form an effective starting torque or thrust, resulting in a "starting dead zone". To avoid this situation, permanent magnets are placed on the mover 2 or in the mover slot 4. Through the interaction between the permanent magnets and the magnetic fields of the left-hand coils 5 and right-hand coils 6, a small "guiding force" is generated, pushing the mover 2 away from the dead zone position, ensuring that the mover 2 can obtain sufficient starting force regardless of its initial position. After the mover 2 has started, the permanent magnets can also serve as an "auxiliary excitation source", reducing the operating current of the left-hand coils 5 and right-hand coils 6, reducing power consumption, and achieving energy saving. This setup is particularly suitable for miniaturized motors, where the size limit prevents the installation of two or more pairs of left-hand coils 5 and right-hand coils 6. In this case, the deficiency of insufficient coil quantity can be compensated by setting a permanent magnet, while avoiding the limitation of relying on external force for starting.

[0043] In one embodiment, please refer to Figures 3-5 and Figures 9-11The left-hand coil 5 and the right-hand coil 6 are spatially intersected, partially intersected, or not intersected at all. When the left-hand coil 5 and the right-hand coil 6 are spatially fully intersected, their magnetic fields form a continuous coupling in the air gap, resulting in more uniform magnetic field superposition, smaller fluctuations in the synthesized electromagnetic thrust and torque, and more stable force on the mover 2. Furthermore, more coils can be arranged within the same stator length, increasing the electromagnetic force density within a limited volume. When the left-hand coil 5 and the right-hand coil 6 are spatially partially intersected, overlapping and winding at the coil ends can be reduced, lowering the difficulty of the winding process and copper loss. When the left-hand coil 5 and the right-hand coil 6 are not spatially intersected, i.e., completely separated in space, the complexity of the winding process is reduced, and in the event of a single coil failure, the corresponding section can be disassembled and repaired individually without replacing the entire stator, thus reducing maintenance costs.

[0044] In one embodiment, please refer to Figure 6 and Figure 14 The mover slot 4 includes a left-handed helical slot 401 and a right-handed helical slot 402. The left-handed helical slot 401 matches the left-handed helical slot 301 of the stator, and the right-handed helical slot 402 matches the right-handed helical slot 302 of the stator. The direction and pitch of the mover slot 4 can be the same as or different from the direction and pitch of the stator slot 3. When the direction and pitch of the mover slot 4 are the same as those of the stator slot 3, the maximum thrust is obtained.

[0045] In one embodiment, please refer to Figure 7 and Figure 15 The mover slot 4 includes a first mover helical slot 403 and a second mover helical slot 404, and the pitches of the first mover helical slot 403 and the second mover helical slot 404 are different. By setting mover slots 4 with different pitches, the ratio of linear force to rotational force in the electromagnetic force can be adjusted, and the force output can be optimized in a targeted manner, thereby optimizing the efficiency of the motor.

[0046] When the mover slot 4 is a helical slot, the function of the mover slot 4 is to guide the magnetic lines of force and ensure that the traveling wave magnetic field generated by the stator 1 can effectively generate thrust and torque on the mover 2.

[0047] In one embodiment, please refer to Figure 8 and Figure 16 The mover slot 4 includes a straight slot 405 and an annular slot 406. The straight slot 405 is parallel to the axis of the mover 2, and the annular slot 406 is perpendicular to the axis of the mover 2. When the mover slot 4 consists of a straight slot 405 and an annular slot 406, the straight slot 405 is used to generate the main linear thrust, and the annular slot 406 acts as a magnetic barrier to adjust the magnetic flux path, optimize the magnetic field waveform, and reduce eddy current losses.

[0048] (II) Control methods for linear motors performing combined rotary and linear motion Please see Figures 1-16 A control method for a linear motor that performs a combined rotary-linear motion includes the following steps: By applying current to the left-hand coil 5 and the right-hand coil 6 through independent current controllers, and by adjusting the direction and intensity of the current in the left-hand coil 5 and the right-hand coil 6, the mover 2 can be driven to perform pure linear motion, pure rotational motion, or a combination of rotation and linear motion.

[0049] Specifically, when the left-hand coil 5 is energized in the forward direction, the magnetic field of the stator 1 drives the rotor 2 to generate a combined force of "rotating to the right + moving forward in a straight line"; when the right-hand coil 6 is energized in the forward direction, the magnetic field of the stator 1 drives the rotor 2 to generate a combined force of "rotating to the left + moving forward in a straight line"; when the left-hand coil 5 is energized in the reverse direction, the magnetic field of the stator 1 drives the rotor 2 to generate a combined force of "rotating to the left + moving backward in a straight line"; when the right-hand coil 6 is energized in the reverse direction, the magnetic field of the stator 1 drives the rotor 2 to generate a combined force of "rotating to the right + moving backward in a straight line".

[0050] When it is necessary to synthesize pure linear motion: control the rotational components generated by the left-hand coil 5 and the right-hand coil 6 to be equal in magnitude and opposite in direction so as to cancel each other out, and control the linear components generated by them to be equal in magnitude and same in direction so as to superimpose them, thereby driving the mover 2 to perform pure linear motion forward or backward along the axis.

[0051] When pure rotational motion needs to be synthesized: the linear components generated by the left-hand coil 5 and the right-hand coil 6 are controlled to be equal in magnitude and opposite in direction to cancel each other out, and the rotational components generated by them are controlled to be equal in magnitude and same in direction to be superimposed, thereby driving the mover 2 to perform pure rotational motion to the left or right around the axis.

[0052] When it is necessary to synthesize a rotary-linear composite motion: control the linear component forces generated by the left-hand coil 5 and the right-hand coil 6 to be equal in magnitude and in the same direction so as to superimpose them, and control the rotational component forces generated by them to be equal in magnitude and in the same direction so as to superimpose them, thereby driving the mover 2 to perform a rotary-linear composite motion along the axis of "rotating and extending".

[0053] In summary, the present invention provides a linear motor and its control method for rotary-linear composite motion. Compared with the prior art: (1) The present invention sets stator left-hand spiral groove and stator right-hand spiral groove with opposite spiral directions on the stator. Left-hand coil and right-hand coil are embedded in the stator left-hand spiral groove and stator right-hand spiral groove respectively. The left-hand coil and right-hand coil are controlled by independent current controllers. When in use, current is applied to the left-hand coil and right-hand coil respectively through independent current controllers. By adjusting the current direction and intensity of the left-hand coil and right-hand coil, the mover is driven to perform pure linear motion, pure rotational motion or rotary-linear composite motion, thereby realizing the decoupling and composite control of the two degrees of freedom of linear and rotation. (2) This invention uses direct electromagnetic drive, eliminating all intermediate transmission components such as "rotary motor + linear motor + gear / lead screw / coupling," simplifying the mechanical structure, eliminating transmission gaps and elastic deformation such as gear meshing clearance and lead screw pitch error, and improving motion accuracy from the millimeter level of traditional equipment to the micrometer level, making it particularly suitable for high-speed precision operations; it also reduces mechanical friction loss and lowers maintenance costs caused by component wear. In addition, this invention uses independent current controllers to adjust the current direction and intensity of the left-hand and right-hand coils respectively, enabling real-time synthesis of arbitrary ratio rotary-linear composite motion without switching mechanical structures, resulting in higher motion control flexibility and adaptability to complex working conditions. Furthermore, this invention integrates two driving functions into the same magnetic circuit system, a unified design that simplifies the mechanical structure and significantly reduces the size of the equipment, making it particularly suitable for multi-dimensional driving scenarios in confined spaces. This invention can be widely applied in the field of motor technology.

[0054] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A linear motor for combined rotary and linear motion, characterized in that, include: The stator (1) has two stator slots (3) with different directions. The stator slots (3) include a stator left-hand spiral slot (301) and a stator right-hand spiral slot (302). A left-hand coil (5) and a right-hand coil (6) are respectively embedded in the stator left-hand spiral slot (301) and the stator right-hand spiral slot (302). The left-hand coil (5) and the right-hand coil (6) form a left-hand winding and a right-hand winding, respectively. The left-hand winding and the right-hand winding are controlled by independent current controllers. The mover (2) has at least two types of mover slots (4). An auxiliary mechanism is used to maintain the concentricity between the stator (1) and the mover (2) and to maintain a uniform air gap between them; The stator (1) is configured as an outer stator, which is sleeved on the outside of the mover (2); Alternatively, the stator (1) may be configured as an inner stator, and the mover (2) may be sleeved on the outside of the stator (1).

2. The linear motor for rotary-linear composite motion according to claim 1, characterized in that, It also includes a base, end caps and a drive shaft. The end caps are disposed at both ends of the base, and the drive shaft is disposed inside the base and passes through the end caps and extends to the outside of the end caps. When the stator (1) is configured as an outer stator, the stator (1) is disposed on the inner wall of the machine base, and the mover (2) is disposed on the outer wall of the transmission shaft. The mover (2) is installed inside the stator (1) through the cooperation of the auxiliary mechanism. When the stator (1) is configured as an inner stator, the stator (1) is installed inside the base by a fixing mechanism, the mover (2) is sleeved on the outside of the stator (1) by the auxiliary mechanism, and the drive shaft is installed on the mover (2).

3. The linear motor for rotary-linear composite motion according to claim 2, characterized in that, When the stator (1) is configured as an external stator, the auxiliary mechanism is an external structure, including a first composite bearing. The first composite bearing is disposed on the end cover. The outer wall of the transmission shaft is in contact with the inner wall of the first composite bearing. The transmission shaft is rotatably connected to and slidably connected to the end cover through the first composite bearing. Alternatively, the auxiliary mechanism is a built-in structure, including a second composite bearing, which is disposed on the inner walls of both ends of the stator (1), and the outer wall of the mover (2) is in contact with the inner wall of the second composite bearing. The mover (2) and the transmission shaft are rotatably and slidably connected to the end cover through the second composite bearing.

4. The linear motor for rotary-linear composite motion according to claim 2, characterized in that, When the stator (1) is configured as an inner stator, the auxiliary mechanism is an internal structure, including a third composite bearing. The third composite bearing is disposed on the inner walls of both ends of the mover (2). The outer wall of the stator (1) is in contact with the inner wall of the third composite bearing. The mover (2) and the transmission shaft are rotatably and slidably connected to the end cover through the third composite bearing. Alternatively, the auxiliary mechanism is a built-in structure, including a fourth composite bearing, which is disposed on the inner wall of the base. The outer wall of the mover (2) is in contact with the inner wall of the fourth composite bearing. The mover (2) and the transmission shaft are rotatably and slidably connected to the end cover through the fourth composite bearing.

5. The linear motor for rotary-linear composite motion according to claim 1, characterized in that, The stator (1) and the mover (2) are configured in columnar or stepped shapes.

6. The linear motor for rotary-linear composite motion according to claim 1, characterized in that, The number of the left-hand coil (5) and the right-hand coil (6) are three or more, forming a three-phase or more multi-phase left-hand winding and a multi-phase right-hand winding, respectively; Alternatively, the number of the left-hand coil (5) and the right-hand coil (6) are both two, forming two-phase left-hand windings and two-phase right-hand windings respectively; Alternatively, the total number of the left-hand coil (5) and the right-hand coil (6) is less than four, and it also includes several permanent magnets, which are circumferentially spaced on the mover (2) or in the mover slot (4).

7. The linear motor for rotary-linear composite motion according to claim 6, characterized in that, The left-hand coil (5) and the right-hand coil (6) may intersect completely, partially, or not intersect in space.

8. The linear motor for rotary-linear composite motion according to claim 1, characterized in that, The mover slot (4) includes a mover left-hand spiral slot (401) and a mover right-hand spiral slot (402). The mover left-hand spiral slot (401) matches the stator left-hand spiral slot (301), and the mover right-hand spiral slot (402) matches the stator right-hand spiral slot (302). Alternatively, the moving part groove (4) includes a first moving part spiral groove (403) and a second moving part spiral groove (404), wherein the pitches of the first moving part spiral groove (403) and the second moving part spiral groove (404) are different; Alternatively, the moving part groove (4) includes a straight groove (405) and an annular groove (406), the straight groove (405) being parallel to the axis of the moving part (2) and the annular groove (406) being perpendicular to the axis of the moving part (2).

9. The control method for a linear motor performing rotary-linear compound motion according to any one of claims 1-8, characterized in that, Includes the following steps: By applying current to the left-hand coil (5) and the right-hand coil (6) respectively through independent current controllers, and by adjusting the current direction and intensity of the left-hand coil (5) and the right-hand coil (6), the mover (2) is driven to perform pure linear motion, pure rotational motion, or a combination of rotation and linear motion.

10. The control method for a linear motor performing rotary-linear composite motion according to claim 9, characterized in that, The method for synthesizing pure linear motion is as follows: control the rotational components generated by the left-hand coil (5) and the right-hand coil (6) to be equal in magnitude and opposite in direction so as to cancel each other out, and control the linear components generated by them to be equal in magnitude and same in direction so as to superimpose them, thereby driving the mover (2) to perform pure linear motion along the axis; The method for synthesizing pure rotational motion is as follows: control the linear component forces generated by the left-hand coil (5) and the right-hand coil (6) to be equal in magnitude and opposite in direction so as to cancel each other out, and control the rotational component forces generated by them to be equal in magnitude and same in direction so as to superimpose them, thereby driving the mover (2) to perform pure rotational motion around the axis; The method for synthesizing the rotary linear composite motion is as follows: control the linear component forces generated by the left-hand coil (5) and the right-hand coil (6) to be equal in magnitude and in the same direction so as to superimpose them, and control the rotational component forces generated by them to be equal in magnitude and in the same direction so as to superimpose them, thereby driving the mover (2) to perform a rotary linear composite motion along the axis of "rotating and stretching".

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