Linear motor primary components, linear motors

Abstract

The present invention provides a primary component of a linear motor and a linear motor, wherein the primary component of the linear motor comprises a first side plane, a primary iron core and an auxiliary tooth combination are mounted on the first side plane, the auxiliary tooth combination is located at at least one of the two ends in the length direction of the primary iron core, the auxiliary tooth combination comprises a first auxiliary tooth, a second auxiliary tooth and a permanent magnet at least partially sandwiched between the first auxiliary tooth and the second auxiliary tooth, the distance between the free end face of the first auxiliary tooth and the first side plane is b1, the distance between the free end face of the second auxiliary tooth and the first side plane is b2, and b1 and b2 are not equal. According to the present invention, the situation of sudden change of the magnetic field at the edge can be improved, so that the magnetic permeability at the edge of the core can change more slowly and smoothly, thereby reducing the positioning force and thrust fluctuation of the motor as a whole.

Description

Technical Field

[0001] The invention belongs to the technical field of linear motor manufacturing, and in particular relates to a linear motor primary component and a linear motor. Background Art

[0002] With the development and continuous upgrading of industrial automation, the efficiency and quality requirements of production and manufacturing are constantly increasing, so higher requirements are also put forward for the speed and accuracy of linear transmission. If the direct drive method is adopted in the linear feed transmission system, no intermediate conversion mechanism is required, and the feed speed range is wide, the speed can reach 100m / min or even higher; the acceleration can reach more than 10g; the positioning accuracy is high, less than μm level, and the structure is simple, the wear is small, the service life is long, and the reliability is high. It is particularly suitable for precision and high-speed applications, such as high-end CNC machine tools, semiconductor processing equipment, laser processing equipment and other industries. "Made in China 2025" plans the high-speed processing machine tool linear motor transmission technology as a high-end CNC machine tool technology development route.

[0003] However, linear motors also have some unique problems. For example, the armature core of the linear motor is disconnected at both ends, and the armature winding is discontinuous at both ends. This situation is called the end effect. At the same time, since the primary core is a slotted structure, a cogging effect will occur, introducing cogging force. Both the cogging force and the end force will cause thrust fluctuations, affecting the servo performance of the linear motor, thereby affecting the application of the linear motor. Existing methods for reducing thrust fluctuations mainly include optimizing slot-pole matching, skewed slots, skewed permanent magnet poles, special-shaped permanent magnets, etc. However, the use of skewed poles and other methods will weaken the effective thrust while reducing thrust fluctuations, and will also increase the complexity of the motor's processing and manufacturing. Summary of the invention

[0004] Therefore, the present invention provides a linear motor primary assembly and a linear motor, which can overcome the shortcomings of the related art that the positioning force of the auxiliary tooth combination is not sufficiently reduced and the thrust fluctuation is still relatively large.

[0005] In order to solve the above problems, the present invention provides a primary component of a linear motor, including a first side plane, on which a primary iron core and an auxiliary tooth combination are installed, the auxiliary tooth combination is located at at least one of the two ends in the length direction of the primary iron core, the auxiliary tooth combination includes a first auxiliary tooth, a second auxiliary tooth and a permanent magnet at least partially sandwiched between the first auxiliary tooth and the second auxiliary tooth, the distance between the free end face of the first auxiliary tooth and the first side plane is b1, the distance between the free end face of the second auxiliary tooth and the first side plane is b2, and b1 and b2 are not equal.

[0006] In some embodiments, a gap is provided between an end of the primary core and the auxiliary tooth assembly.

[0007] In some embodiments, the gap is filled with insulating thermally conductive material.

[0008] In some embodiments, the first auxiliary tooth is located between the primary core and the second auxiliary tooth, and b1>b2.

[0009] In some embodiments, the primary core includes a yoke and a plurality of spaced-apart teeth on the yoke, the distance between the free end face of the tooth and the first side plane is b0, b0≥b1; and / or, any plane perpendicular to the stacking height direction of the first auxiliary tooth is a first projection plane, and on the first projection plane, the width a1 of the first auxiliary tooth is not less than the width a2 of the second auxiliary tooth.

[0010] In some embodiments, the auxiliary tooth assembly further includes an eddy current damper, which is sandwiched between the first auxiliary tooth and the second auxiliary tooth, and is located on a side of the permanent magnet away from the first side plane.

[0011] In some embodiments, the eddy current damper has a first clamping portion and a second clamping portion relative to each other, and the first clamping portion and the second clamping portion respectively correspond to the two ends of the stacking height direction of the first auxiliary tooth and the second auxiliary tooth to clamp the first auxiliary tooth and the second auxiliary tooth; and / or the eddy current damper includes a copper sheet.

[0012] In some embodiments, the free end face of the first auxiliary tooth and the free end face of the second auxiliary tooth have a slope on the side away from the primary iron core, and on the first projection plane, the slope forms an angle A with the first side plane being 0°<A≤45°; and / or, the distance between the free end face of the eddy current damper and the free end face of the first auxiliary tooth is smaller than the distance between the free end face of the second auxiliary tooth and the free end face of the first auxiliary tooth, and the free end face of the eddy current damper does not exceed the free end face of the first auxiliary tooth.

[0013] In some embodiments, the permanent magnet has a parallel portion parallel to the first side plane and a vertical portion perpendicular to the parallel portion, the first auxiliary tooth and the second auxiliary tooth are respectively located on both sides of the vertical portion and on the side of the parallel portion away from the first side plane; and / or the stacking height of the primary iron core is greater than the stacking height of the first auxiliary teeth and the second auxiliary teeth, and greater than the height of the permanent magnet in the stacking height direction of the primary iron core.

[0014] The present invention also provides a linear motor, comprising a primary component, wherein the primary component is the above-mentioned linear motor primary component.

[0015] The present invention provides a linear motor primary component and a linear motor. By designing the first auxiliary tooth and the second auxiliary tooth in the auxiliary tooth combination to have different distances corresponding to the first side plane, a step structure is formed at the corresponding free end position. The magnetic permeance is different at the air gap, which can improve the sudden change of the magnetic field at the edge end, and enable the magnetic permeance at the edge end of the iron core to change more slowly and smoothly, thereby reducing the overall positioning force and thrust fluctuation of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the primary assembly of the linear motor according to an embodiment of the present invention (first projection plane perspective);

[0017] Figure 2 It is a structural schematic diagram of a primary assembly of a linear motor according to another embodiment of the present invention (from a first projection plane perspective);

[0018] Figure 3 for Figure 1 Schematic diagram of the local structure;

[0019] Figure 4 It is a structural schematic diagram of a primary assembly of a linear motor according to another embodiment of the present invention (from a first projection plane perspective);

[0020] Figure 5 It is a structural schematic diagram of a primary assembly of a linear motor according to another embodiment of the present invention (from a first projection plane perspective);

[0021] Figure 6 for Figure 4 The three-dimensional structural diagram of the primary component of the linear motor shown;

[0022] Figure 7 It is a thrust fluctuation simulation curve diagram of a linear motor adopting the technical solution of the present invention and the technical solution of two auxiliary teeth of equal height in the auxiliary tooth combination in the related art.

[0023] The reference numerals are:

[0024] 1. Primary iron core; 11. Yoke; 12. Teeth; 21. First auxiliary teeth; 22. Second auxiliary teeth; 23. Permanent magnet; 231. Parallel portion; 232. Vertical portion; 24. Eddy current damper; 241. First clamping portion; 242. Second clamping portion; 3. Three-phase winding; 4. Insulating thermal conductive material. DETAILED DESCRIPTION

[0025] Since the ends of the linear motor are disconnected, the primary winding is discontinuous and the mutual inductances are unequal. Even if a three-phase symmetrical voltage is applied, a symmetrical stator current will not be generated. In addition to the positive-sequence traveling wave magnetic field, the air gap magnetic field also has reverse-sequence and zero-sequence magnetic fields. Therefore, there is a pulsating magnetic field in the air gap. Even if the current passed through the three-phase winding is symmetrical, the longitudinal end effect will cause a pulsating magnetic field in the air gap, thereby generating thrust fluctuations. At the same time, both ends of the armature core of the linear motor are disconnected, and the air gap magnetic resistance changes sharply at the ends, causing periodic fluctuations in the thrust, which is similar to the mechanism for generating cogging force.

[0026] The end force can be obtained by superimposing the single-end end force. Assuming that the mover length is long enough, when the mover length is greater than 3 to 4 pole pitches, the magnetic field interaction between the left and right ends can be ignored, and the force generated by the end effect can be regarded as the sum of the left and right end forces. The forces at the same position at both ends are obviously equal. The positioning force is expressed as the sum of two sine waves with the same frequency and amplitude and a certain phase difference, as follows:

[0027] Left end force

[0028] Right end force

[0029] The end forces at both ends and

[0030] Where τ is the pole pitch, x is the lateral position of the mover (i.e. primary); Δ = kτ-L a , La is the mover (i.e. primary) length, which is the mover length minus the remainder of the integer multiple of the pole pitch.

[0031] See also Figures 1 to 7As shown, according to an embodiment of the present invention, a primary component of a linear motor is provided, including a mounting plate (not shown in the figure), a primary iron core 1 and an auxiliary tooth combination are mounted on a first side plane of the mounting plate, a three-phase winding 3 is wound on the primary iron core 1, the auxiliary tooth combination is located at at least one of the two ends in the length direction of the primary iron core 1, the auxiliary tooth combination includes a first auxiliary tooth 21, a second auxiliary tooth 22 and a permanent magnet 23 at least partially sandwiched between the first auxiliary tooth 21 and the second auxiliary tooth 22, the distance between the free end face of the first auxiliary tooth 21 and the first side plane is b1, the distance between the free end face of the second auxiliary tooth 22 and the first side plane is b2, and b1 and b2 are not equal. In this technical solution, by designing the first auxiliary tooth 21 and the second auxiliary tooth 22 in the auxiliary tooth combination to have different distances corresponding to the first side plane, a step structure is formed at the corresponding free end position, and the magnetic permeance is different at the air gap. This can improve the sudden change of the magnetic field at the edge end, and enable the magnetic permeance at the edge end of the core to change more slowly and smoothly, thereby reducing the overall positioning force and thrust fluctuation of the motor.

[0032] The aforementioned free end face is specifically the end face of the corresponding component facing the secondary side, and the same applies to the following.

[0033] Best, the auxiliary tooth combination can be arranged correspondingly at both ends of the primary iron core 1 in the length direction, which can balance the end magnetic field and the magnetic field in the middle of the main teeth of the iron core to a certain extent, so that the back electromotive force of the three-phase winding 3 is more balanced, and the effective thrust will not be weakened while reducing the thrust fluctuation.

[0034] The first auxiliary tooth 21, the second auxiliary tooth 22 and the permanent magnet 23 in the auxiliary tooth combination can be reliably connected to each other by bonding, pinning, etc. In some embodiments, the first auxiliary tooth 21, the second auxiliary tooth 22 and the primary iron core 1 are all constructed with corresponding threaded holes on the side facing the mounting plate to achieve a detachable connection between the three and the mounting plate.

[0035] It can be understood that the first auxiliary teeth 21, the second auxiliary teeth 22 and the primary iron core 1 are all formed by stacking corresponding punching sheets, and the specific materials can be consistent. In some embodiments, the first auxiliary teeth 21 and the second auxiliary teeth 22 can be made of 45# steel and other magnetically conductive materials with good processability.

[0036] In some embodiments, there is a gap between the end of the primary core 1 and the auxiliary tooth combination, that is, the primary core 1 and the auxiliary tooth combination are a split structure rather than an integrated structure. This independent auxiliary tooth combination structure is more conducive to the universalization of the core mold, especially in the process of product series development. The main teeth of the core are expanded according to actual needs, and the corresponding auxiliary tooth sizes are designed to match according to different situations, which greatly improves the utilization rate of the mold, reduces the number of molds, and saves production costs.

[0037] After the auxiliary tooth assembly and the primary core 1 are respectively positioned and connected to the mounting plate, the gap is filled with an insulating thermally conductive material, such as epoxy resin. In some cases, the insulating thermally conductive material can be filled outside the linear motor assembly to improve its insulation and heat dissipation performance.

[0038] In some embodiments, the first auxiliary tooth 21 is between the primary iron core 1 and the second auxiliary tooth 22, and b1>b2, which can further improve the effect of the auxiliary tooth combination in reducing the positioning force, further improve the sudden change of the edge magnetic field, and enable the magnetic permeability of the edge of the iron core to change more slowly and smoothly, thereby further reducing the thrust fluctuation of the motor.

[0039] The primary iron core 1 includes a yoke 11 and a plurality of spaced teeth 12 on the yoke 11, wherein the distance between the free end face of the tooth 12 and the first side plane is b0, b0≥b1, that is, the free end faces of the first auxiliary tooth 21 and the second auxiliary tooth 22 are not higher than the free end faces of the tooth 12, which can further improve the effect of the auxiliary tooth combination in reducing the positioning force, further improve the sudden change of the magnetic field at the edge end, so that the magnetic permeability at the edge end of the iron core can change more slowly and smoothly, further reducing the thrust fluctuation of the motor.

[0040] Any plane perpendicular to the stacking height direction of the first auxiliary tooth 21 is defined as a first projection plane. On the first projection plane, the width a1 of the first auxiliary tooth 21 is not less than the width a2 of the second auxiliary tooth 22, so that its interaction with the secondary can generate magnetic resistance forces with different phases. The magnetic resistance forces generated by the two auxiliary teeth and the positioning force generated by the iron core are superimposed and offset on each other, thereby achieving the effect of reducing the overall positioning force and thrust fluctuation of the motor.

[0041] In some embodiments, the auxiliary tooth combination also includes an eddy current damper 24, which is sandwiched between the first auxiliary tooth 21 and the second auxiliary tooth 22. The eddy current damper 24 is located on the side of the permanent magnet 23 away from the first side plane. The eddy current damper 24 can be made of copper sheet, for example. When the mover and the stator move relative to each other, eddy currents will be generated in the copper sheet due to the principle of electromagnetic induction. The thrust fluctuation can be adjusted by damping action, which can further reduce the thrust fluctuation.

[0042] As a specific implementation method, the eddy current damper 24 has a first clamping portion 241 and a second clamping portion 242 relative to each other, and the first clamping portion 241 and the second clamping portion 242 respectively correspond to the two ends of the stacking direction of the first auxiliary tooth 21 and the second auxiliary tooth 22 to clamp the first auxiliary tooth 21 and the second auxiliary tooth 22, that is, on the first projection plane, the eddy current damper 24 is in an I-shape, which can clamp and reinforce the first auxiliary tooth 21 and the second auxiliary tooth 22 in the stacking direction.

[0043] In some embodiments, the free end faces of the first auxiliary tooth 21 and the free end faces of the second auxiliary tooth 22 have an inclined surface on the side away from the primary iron core 1. On the first projection plane, an angle A is formed between the inclined surface and the first side plane. The design of the first inclined surface can be beneficial to improving the magnetic field and further reducing the positioning force. As a more optimal implementation method, 0°<A≤45°, the inclined surface passes through the midpoint of the width of the first auxiliary tooth 21 or the midpoint of the width of the second auxiliary tooth 22, so that the first auxiliary tooth 21 and the second auxiliary tooth 22 both have a plane parallel to the first side plane, reducing the magnetic field saturation at the bottom of the tooth and reducing motor losses.

[0044] The distance between the free end face of the eddy current damper 24 and the free end face of the first auxiliary tooth 21 is smaller than the distance between the free end face of the second auxiliary tooth 22 and the free end face of the first auxiliary tooth 21 , and the free end face of the eddy current damper 24 does not exceed the free end face of the first auxiliary tooth 21 .

[0045] In some embodiments, the permanent magnet 23 can be rectangular or T-shaped. When it is T-shaped, the permanent magnet 23 has a parallel portion 231 parallel to the first side plane and a vertical portion 232 perpendicular to the parallel portion 231. The first auxiliary tooth 21 and the second auxiliary tooth 22 are respectively located on both sides of the vertical portion 232 and on the side of the parallel portion 231 away from the first side plane.

[0046] In some embodiments, the stacking height of the primary core 1 is greater than the stacking height of the first auxiliary teeth 21 and the second auxiliary teeth 22 , and greater than the height of the permanent magnet 23 in the stacking height direction of the primary core 1 .

[0047] Figure 7 It can be seen that the linear motor in the present invention has smaller thrust fluctuation than the linear motor in the prior art, that is, the amplitude of the thrust fluctuation is smaller.

[0048] According to an embodiment of the present invention, there is further provided a linear motor, comprising a primary component, wherein the primary component is the above-mentioned linear motor primary component.

[0049] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0050] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A linear motor primary assembly, characterized in that: The invention comprises a first side plane, on which a primary iron core (1) and an auxiliary tooth assembly are mounted, the auxiliary tooth assembly being located at at least one of the two ends in the length direction of the primary iron core (1), the auxiliary tooth assembly comprising a first auxiliary tooth (21), a second auxiliary tooth (22) and a permanent magnet (23) at least partially sandwiched between the first auxiliary tooth (21) and the second auxiliary tooth (22), the distance between the free end face of the first auxiliary tooth (21) and the first side plane being b1, the distance between the free end face of the second auxiliary tooth (22) and the first side plane being b2, and b1 and b2 being unequal; the primary iron core (1) There is a gap between the end and the auxiliary tooth combination; the first auxiliary tooth (21) is between the primary iron core (1) and the second auxiliary tooth (22), and b1>b2; the primary iron core (1) includes a yoke (11) and a plurality of spaced teeth (12) on the yoke (11), the distance between the free end face of the tooth (12) and the first side plane is b0, b0≥b1; and / or any plane perpendicular to the stacking direction of the first auxiliary tooth (21) is a first projection plane, and on the first projection plane, the width a1 of the first auxiliary tooth (21) is not less than the width a2 of the second auxiliary tooth (22).

2. The linear motor primary component according to claim 1, characterized in that: The gap is filled with insulating heat-conducting material (4).

3. The linear motor primary component according to claim 1, characterized in that: The auxiliary tooth assembly further comprises an eddy current damping member (24), wherein the eddy current damping member (24) is sandwiched between the first auxiliary tooth (21) and the second auxiliary tooth (22), and the eddy current damping member (24) is located on a side of the permanent magnet (23) away from the first side plane.

4. The linear motor primary component according to claim 3, characterized in that: The eddy current damping member (24) has a first clamping portion (241) and a second clamping portion (242) which are opposite to each other, and the first clamping portion (241) and the second clamping portion (242) respectively correspond to two ends of the stacking direction of the first auxiliary tooth (21) and the second auxiliary tooth (22) to clamp the first auxiliary tooth (21) and the second auxiliary tooth (22); and / or the eddy current damping member (24) comprises a copper sheet.

5. The linear motor primary component according to claim 3, characterized in that: The free end face of the first auxiliary tooth (21) and the free end face of the second auxiliary tooth (22) have an inclined surface on the side away from the primary core (1), and on the first projection plane, an angle A is formed between the inclined surface and the first side plane, 0°<A≤45°; and / or the distance between the free end face of the eddy current damping element (24) and the free end face of the first auxiliary tooth (21) is smaller than the distance between the free end face of the second auxiliary tooth (22) and the free end face of the first auxiliary tooth (21), and the free end face of the eddy current damping element (24) does not exceed the free end face of the first auxiliary tooth (21).

6. The linear motor primary component according to claim 1, characterized in that: The permanent magnet (23) has a parallel portion (231) parallel to the first side plane and a vertical portion (232) vertical to the parallel portion (231); the first auxiliary tooth (21) and the second auxiliary tooth (22) are respectively located on both sides of the vertical portion (232) and on the side of the parallel portion (231) away from the first side plane; and / or the stacking height of the primary iron core (1) is greater than the stacking height of the first auxiliary tooth (21) and the second auxiliary tooth (22), and is greater than the height of the permanent magnet (23) in the stacking height direction of the primary iron core (1).

7. A linear motor comprising a primary assembly, characterized in that: The primary component is a linear motor primary component according to any one of claims 1 to 6.

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