A two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor

Abstract

The application provides a double-stage permanent magnet cylinder type transverse flux permanent magnet linear motor, which comprises a primary iron core, a secondary iron core, permanent magnets, coils and a machine shell; the primary iron core is formed by j unit primary iron cores through long and short tooth staggered coaxial axial lamination; the primary permanent magnets are installed on the surface of the short teeth of the primary iron core; the coils of the armature winding are wound on the teeth of the primary iron core according to m phases in the circumferential direction; the secondary iron core is coaxially installed in the primary iron core; and the secondary permanent magnets are installed on the surface of the secondary iron core according to m phases in the circumferential direction. The primary iron core is provided with the permanent magnets, which increases the thrust density of the motor and the space utilization rate of the primary iron core, and the permanent magnets are directly cooled through the primary iron core and the machine shell; the permanent magnets on the secondary iron core are installed in a magnetic gathering mode, which greatly improves the space utilization rate of the permanent magnets and saves the cost of the motor; the motor adopts a concentrated winding, the tooth part and the yoke part of the primary iron core are formed by one-time lamination of silicon steel sheets, and is suitable for batch production.

Description

Technical Field

[0001] This invention belongs to the field of cylindrical permanent magnet linear motors, and more specifically, relates to a two-stage cylindrical permanent magnet linear motor with permanent magnets mounted on a primary and secondary stage, and the moving and force-bearing components being a secondary iron core and a permanent magnet. Background Technology

[0002] Traditionally, linear motion in industry has largely relied on pneumatic, hydraulic, and ball screw transmission mechanisms. These traditional linear motion devices are notorious for their complex structures, high wear and tear, difficult maintenance, low efficiency and power factor, and large size. The use of "zero-transmission" permanent magnet linear motors to achieve reciprocating linear motion not only eliminates the need for intermediate transmission mechanisms such as cranks but also significantly improves efficiency and power factor, thus attracting widespread attention.

[0003] Depending on the primary and secondary structures, permanent magnet linear motors can be classified into single-sided flat plate type, double-sided flat plate type, and cylindrical type; according to the different magnetic field distribution, permanent magnet linear motors can be classified into traditional magnetic flux structure and transverse magnetic flux structure.

[0004] Traditional cylindrical permanent magnet linear motors with magnetic circuit structures have a major drawback: because the teeth through which the magnetic flux passes and the slots where the windings reside are on the same cross-section, their sizes are mutually constrained, making it difficult to fundamentally improve the motor's force density. Although output can be increased through optimized magnetic circuit design and the use of high-performance magnetic materials, the effect is limited. Furthermore, adjacent permanent magnets within each phase are magnetized in opposite directions without intervals on the secondary core. Therefore, traditional cylindrical permanent magnet linear motors with magnetic circuit structures have low thrust density, high cost of secondary permanent magnets, and significant magnetic leakage.

[0005] A cylindrical permanent magnet linear motor with a transverse flux structure. Its main drawback is that, although the transverse flux structure decouples the electrical and magnetic loads, resulting in a different arrangement of secondary permanent magnets compared to traditional permanent magnet linear motors, reduced magnetic leakage, and improved space utilization, the number of permanent magnets is not significantly increased, thus only providing a limited increase in thrust density. Therefore, the transverse flux structure cylindrical permanent magnet linear motor requires further improvement.

[0006] In both traditional and transverse flux cylindrical permanent magnet linear motors, the permanent magnets are only mounted on the secondary stage. Their common drawback is that with the permanent magnets only on the secondary, the primary space utilization is low, and the thrust density is always limited by the number of permanent magnets, resulting in significant magnetic leakage. This leads to low reliability, especially under high-frequency oscillations and harsh operating conditions. Summary of the Invention

[0007] To address the problems of existing technologies, this invention provides a two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor. Its purpose is to improve the thrust density of the motor, increase the space utilization of the primary stage, improve the reliability, safety, and maintainability of the motor, simplify the manufacturing process, and improve its mass production capability.

[0008] A two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor includes a primary iron core, a secondary iron core, permanent magnets, coils, and a housing. The primary core is formed by axially stacking j unit primary cores. Each pair of adjacent unit primary cores are coaxially connected by alternating long and short teeth and are axially aligned and installed inside the housing. Each unit primary core contains p long teeth and p short teeth. Multiple permanent magnets are uniformly embedded in each primary core short tooth along the circumferential and axial directions. Multiple coils that make up the armature winding are wound on the primary core teeth, and any adjacent coils in the same phase are connected in reverse series. The secondary core is coaxially and centrally installed inside the primary core, with an equal-length air gap between it and the primary core in the radial direction.

[0009] Furthermore, both the primary core and the secondary core are formed by axially stacking non-oriented silicon steel sheets.

[0010] Furthermore, each phase of the coil consists of 2n (n is a natural number) coils, which are wound in a racetrack shape around the teeth of the primary iron core.

[0011] Furthermore, both the secondary core and the primary core are equipped with permanent magnets.

[0012] Furthermore, the permanent magnets installed on the surface of the short teeth of the primary iron core have an arc-shaped structure and are installed on the surface of the short teeth of the primary iron core at intervals of one long tooth of the primary iron core, and any two adjacent permanent magnets on the same primary iron core have the same magnetization direction.

[0013] Furthermore, the permanent magnets on the secondary core are mounted circumferentially on its surface according to the m phases, with the permanent magnets in each phase spaced apart by a pole pitch, and the permanent magnets in adjacent phases spaced apart by two-thirds of the pole pitch.

[0014] The beneficial technical effects of this invention are reflected in: (1) A two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor is used as the drive mechanism for reciprocating linear motion, which eliminates the complex crank-connecting rod device, resulting in a more compact structure, less friction of parts, low transmission loss, and high efficiency. (2) The magnetic circuit design with transverse magnetic flux simplifies the stacking process of silicon steel sheets; (3) The primary iron core is stacked into a whole unit. The primary teeth are divided into short teeth and long teeth. The permanent magnet is installed on the surface of the primary short teeth, which reduces the processing difficulty of the primary iron core and the installation difficulty of the permanent magnet, making it convenient to install, disassemble, maintain and replace, and saving manufacturing and maintenance costs. (4) A dual-stage permanent magnet structure is adopted, that is, permanent magnets are installed in both the primary and secondary stages. Compared with the traditional cylindrical permanent magnet linear motor, the permanent magnet on the primary stage increases the overall thrust density of the motor. Furthermore, because the permanent magnet is installed on the iron core, its heat dissipation capacity is increased, protecting the permanent magnet on the primary stage, improving the reliability and robustness of the motor and the space utilization of the primary stage, and extending the service life of the motor. (5) The permanent magnets on the secondary core are installed in the circumferential direction of m phases on its surface. The permanent magnets in each phase are spaced apart by one pole pitch, and the permanent magnets of adjacent phases are spaced apart by two-thirds of the pole pitch, which reduces both magnetic leakage and the cost of permanent magnets. (6) The length of the dual permanent magnet and the secondary iron core has been optimized to reduce the magnetic resistance of the secondary within the stroke range and increase the output force.

[0015] In summary, compared to traditional structures, this invention features permanent magnets installed in both the primary and secondary stages, employing a transverse magnetic flux structure. This significantly improves the motor's safety, reliability, and robustness. Installing permanent magnets in the primary stage increases thrust density, and the permanent magnets dissipate heat directly through the primary core and housing, facilitating heat dissipation. Installing permanent magnets in the secondary stage in the same manner reduces magnetic leakage and motor cost, while also improving the space utilization of the primary core. Through reasonable dimensional design, the secondary stage exhibits low magnetic resistance, high thrust, and strong overload capacity within its effective stroke range. This novel motor is suitable for applications such as electric motors, pumps, and other bidirectional reciprocating motions requiring high thrust. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the primary iron core, the arrangement of permanent magnets, and the coil winding.

[0017] Figure 2 This is a cross-sectional view of an embodiment of the present invention.

[0018] Figure 3 It is a primary iron core.

[0019] Figure 4 It is a primary iron core with a permanent magnet.

[0020] Figure 5 It is a three-phase winding.

[0021] Figure 6 It consists of two types of primary iron cores with permanent magnets.

[0022] Figure 7 It is secondary.

[0023] In the diagram: 1. Housing; 2. Primary iron core; 3. Coil; 4. Primary short tooth; 5. Primary permanent magnet; 6. Primary long tooth; 7. Secondary permanent magnet; 8. Secondary iron core; 9. Phase A; 10. Phase B; 11. Phase C. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] The working principle of the motor of this invention is as follows: When the permanent magnet flux linkage of the winding reaches its positive maximum value, it can be divided into two groups of teeth: one group is called the excitation teeth, in which the primary permanent magnet 5 is aligned with the secondary iron core 8, and the primary iron core 2 is aligned with the secondary permanent magnet 7. The effective magnetic flux generated by the primary and secondary permanent magnets passes through the gap and connects to the winding; the other group is called the leakage teeth, in which the primary permanent magnet 5 is aligned with the secondary permanent magnet 7, and the primary iron core 2 is aligned with the secondary iron core 8. Both the primary and secondary permanent magnets will generate useless leakage flux; when the relative positions move by one pole pitch, the alignment relationship is reversed. The excitation teeth and leakage teeth are interchanged, and the leakage teeth and excitation teeth are interchanged; at the same time, the permanent magnet flux linkage in the winding is exchanged to the negative maximum value, which means that a back electromotive force is generated in the winding; similar to the traditional permanent magnet motor, in the two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor, the permanent magnet flux linkage excited by the permanent magnet motor crosses the winding. If the relative position between the primary and secondary stages changes with the movement of the moving parts, the alternating permanent magnet flux linkage will generate a back electromotive force; according to the law of conservation of energy, when a sinusoidal alternating current with a suitable phase is applied to the winding, an electromagnetic thrust will be generated.

[0026] like Figure 1As shown, the primary and secondary stages of the dual-stage permanent magnet cylindrical transverse flux permanent magnet linear motor include: a housing 1, a primary iron core 2, a coil 3, primary short teeth 4, a primary permanent magnet 5, a primary long teeth 6, a secondary permanent magnet 7, and a secondary iron core 8; the primary iron core 2 is composed of 8 stacked primary iron core units, each unit containing primary short teeth 4, primary long teeth 6, and tooth slots, wherein primary permanent magnets 5 are mounted on the primary iron core short teeth 4, and any adjacent primary permanent magnets 5 have the same magnetization direction; Coils are wound on the primary short teeth 4 and the primary long teeth 6. The currents in any adjacent coils within the same phase are in opposite directions, i.e., they are connected in reverse series. The secondary permanent magnets 7 are installed circumferentially on the surface of the secondary iron core in accordance with the three phases ABC. The permanent magnets 7 in each phase are spaced apart by a pole pitch, and the permanent magnets in two adjacent phases are spaced apart by two-thirds of the pole pitch. Whether it is the unit primary iron core, the secondary iron core 8, or the permanent magnets, their shapes are relatively regular and simple, and the iron core stacking method is consistent with that of the rotating motor, making the process simple.

[0027] like Figure 2 As shown, the primary iron core 2 is formed by axially stacking 8 unit primary iron cores and axially aligned and installed inside the housing 1. Each unit primary iron core consists of 6 long teeth, 6 short teeth, and 12 slots, which are arranged alternately on the unit primary iron core. Each primary iron core short tooth 4 is uniformly embedded with multiple primary permanent magnets 5 along the circumference and axial direction. Multiple coils 3 that make up the armature winding are wound on the primary short teeth 4 and primary long teeth 6, and any adjacent coils in the same phase are connected in reverse series. The secondary iron core 8 is concentric with the primary iron core 2 and fixed in the inner circle of the primary iron core with an equal air gap in the radial direction.

[0028] The primary iron core 2 is formed by axially stacking unit primary iron cores into a column shape. Adjacent unit primary iron cores are connected by alternating long and short teeth. This alternation of the primary teeth causes the permanent magnets to interweave, increasing thrust density and reducing magnetic leakage. The housing 1 can be cast from aluminum or other high-strength, magnetically shielding metal materials, serving to fix the primary iron core 2 and shield the electromagnetic field. The end cap can be made of aluminum alloy or other high-strength profiles to prevent motor magnetic leakage, providing fixation and protection. The secondary iron core 8 is composed of… Figure 1 The cylindrical secondary core shown can be made of stacked circular silicon steel sheets and is located in the center inside the primary core; the currents in adjacent coils within the same phase are in opposite directions, that is, adjacent coils within the same phase are connected in reverse series to form the primary armature winding.

[0029] The winding method of the coil 3 constituting the armature winding is as follows: 12 primary coils are used, and the 12 coils are wound on 12 primary teeth respectively; any adjacent coils in the same phase must be connected in reverse series to form the armature winding; when a sinusoidal alternating current with appropriate phase is applied to the winding, an electromagnetic thrust is generated on the primary to the secondary.

[0030] The primary permanent magnet 5, which is mounted on the surface of the short tooth 4 of the primary iron core, has an arc-shaped structure. It is mounted on the surface of the short tooth 4 of the primary iron core in such a way that there is a gap of one primary long tooth 6 between each pair of the two permanent magnets. Furthermore, any two adjacent permanent magnets on the same primary iron core 2 have the same magnetization direction.

[0031] During operation, the motor drive unit consists of the primary iron core 2, the primary permanent magnet 5 mounted on the primary iron core 2, and the coil on the primary teeth, which drives the secondary iron core 8 and the secondary permanent magnet 7 to perform reciprocating linear motion. Specifically, when a three-phase sinusoidal alternating current of a certain frequency is passed through the primary armature winding, the primary armature magnetic field and the permanent magnet magnetic field combine in the air gap to form a periodic air gap magnetic field, thereby driving the secondary iron core 8 and the secondary permanent magnet 7 to perform reciprocating linear motion within the designed effective stroke range, thereby outputting power to the outside.

[0032] Simulation analysis and prototype experiments have proven that the dual-stage permanent magnet cylindrical transverse flux permanent magnet linear motor of the present invention has a simple processing technology, low assembly, disassembly and maintenance costs, strong safety, reliability and robustness, good heat dissipation, and long service life. Within the designed effective stroke range, it has low magnetic resistance and large output static thrust, making it suitable for applications of high-thrust linear motion such as electric motors or pumps.

Claims

1. A two-stage permanent magnet cylindrical transverse flux permanent magnet linear motor, characterized in that, Includes housing (1), primary iron core (2), coil (3), primary short tooth (4), primary permanent magnet (5), primary long tooth (6), secondary permanent magnet (7), and secondary iron core (8); The primary iron core (2) is a primary iron core with permanent magnets, which is formed by axially stacking multiple unit primary iron cores and axially aligned and installed inside the housing (1); the primary iron core (2) includes multiple primary long teeth (6) and multiple primary short teeth (4), and the surface of the primary short teeth (4) is uniformly equipped with arc-shaped primary permanent magnets (5) along the circumferential and axial directions, and the magnetization direction of any two adjacent primary permanent magnets (5) is the same; The secondary core (8) is concentrically installed inside the primary core (2) and is separated radially by an air gap. The secondary core (8) is provided with a secondary permanent magnet (7). The secondary permanent magnets (7) are distributed in m phases in the circumferential direction. The secondary permanent magnets (7) in each phase are spaced apart by a pole pitch, and the secondary permanent magnets (7) in two adjacent phases are spaced apart by two-thirds of the pole pitch. The coil (3) is wound in a racetrack shape on the teeth of the primary iron core. Each phase includes 2n coils, where n is a natural number. Any adjacent coils in the same phase are connected in reverse series. The magnetic circuit structure of this motor is a transverse magnetic flux structure.

Images