Eddy current sensor

Abstract

The invention discloses an eddy current sensor, the eddy current sensor comprises a rotor and a coil assembly, the coil assembly comprises a circuit board, a receiving coil and an exciting coil, the receiving coil comprises a first coil and a second coil, the first coil comprises a plurality of coil segments connected in sequence, each coil segment comprises a first segment and a second segment, a cylindrical surface coaxial with the yoke part and passing through a connecting point of the first section and the second section is defined, the first section and the second section are located on the two sides of the cylindrical surface respectively, the diameter of the yoke part passing through the connecting point is defined as a preset diameter, and the first section and the second section are located on the two sides of the preset diameter respectively; the first section and the second section are each composed of at least two wires extending in the linear direction. The second coil and the first coil are consistent in structure, the sine coil and the cosine coil are consistent in structure, and the excitation coil is installed on the circuit board and surrounds the receiving coil. Through the arrangement, the resolution ratio, the signal-to-noise ratio and the anti-interference performance of the eddy current sensor can be improved.

Description

Technical Field

[0001] This application relates to the technical field of detection equipment, and particularly to an eddy current sensor. Background Art

[0002] In the current detection field, eddy current sensors based on electromagnetic induction and without magnets have obvious advantages of small volume and weight, low cost, and strong robustness.

[0003] The performance design of an eddy current sensor focuses on its receiving coil. The receiving coil structure of existing eddy current sensors is usually a sinusoidal 2-phase (sin phase and cos phase), with each phase containing 1 - 2 groups, each group containing 2 turns, and each turn being segmented and distributed on 2 layers of the PCB, forming a complete closed sinusoidal trajectory.

[0004] Among them, an eddy current sensor can increase the amplitude of its output signal, which helps to improve its signal-to-noise ratio and anti-interference ability. The amplitude of the output signal of an eddy current sensor is the amplitude of the induced voltage of its receiving coil, and the main influencing factors of this amplitude are: the width of the coil induction area, the total effective induction area, and the number of turns per phase.

[0005] For current eddy current sensors, due to the inherently low design freedom of the sinusoidal trace of the receiving coil, its maximum number of pole pairs and the number of turns per phase are limited by the trace density, and the utilization rate of the total effective induction area of the coil under a certain induction area width is not high. Therefore, it will restrict the improvement of important performance such as the resolution, signal-to-noise ratio, and anti-interference ability of eddy current sensors. Summary of the Invention

[0006] In order to solve the deficiencies of the prior art, the purpose of this application is to provide an eddy current sensor with better resolution, signal-to-noise ratio, and anti-interference ability.

[0007] To achieve the above purpose, this application adopts the following technical solutions: An eddy current sensor, which includes a rotor and a coil assembly. The rotor includes a yoke and a plurality of teeth. The yoke has an annular structure. Each tooth extends radially along the yoke. The plurality of teeth are evenly distributed on the outer peripheral surface of the yoke. A tooth groove is formed between two adjacent teeth. Along the circumferential direction of the yoke, the width of the tooth groove is the same as the width of the tooth and is defined as a preset width. The coil assembly is located on one side of the rotor along the axial direction of the yoke. The coil assembly includes a circuit board, a receiving coil, and an exciting coil. The receiving coil includes a cosine coil and a sine coil mounted on the circuit board. The cosine coil includes a first coil and a second coil. The first coil includes a plurality of sequentially connected coil segments. Each coil segment includes a first section and a second section. Along the circumferential direction of the yoke, the width of the first section and the width of the second section are both the preset width. Define a cylindrical surface that is coaxial with the yoke and passes through the connection point of the first section and the second section. The first section and the second section are respectively located on both sides of the cylindrical surface. Define the diameter of the yoke passing through the connection point as the preset diameter. The first section and the second section are respectively located on both sides of the preset diameter. The first section and the second section are each composed of at least two wires extending in a straight line direction. The second coil has the same structure as the first coil. When the second coil moves a preset width along the circumferential direction of the yoke, the second coil and the first coil overlap axially along the yoke. The sine coil has the same structure as the cosine coil. When the sine coil moves a distance of half of the preset width along the circumferential direction of the yoke, the sine coil and the cosine coil overlap axially along the yoke. The exciting coil is mounted on the circuit board and is arranged around the receiving coil.

[0008] Further, the cosine coil can generate a sine envelope waveform signal, and the sine coil can generate a cosine envelope waveform signal.

[0009] Further, the first section includes a first part and a second part extending radially along the yoke and a third part extending perpendicular to the radial direction of the yoke. The first part, the third part, and the second part are sequentially connected. The structure of the second section is basically the same as that of the first section.

[0010] Further, the first section includes a first part forming an acute angle with the radial direction of the yoke, a second part forming an acute angle with the radial direction of the yoke, and a third part extending perpendicular to the radial direction of the yoke. The first part, the third part, and the second part are sequentially connected. The structure of the second section is basically the same as that of the first section.

[0011] Further, the first section further includes a first transition part. The first transition part extends along a straight line. The first transition part is connected between the first part and the third part. The first transition part enables the first part and the third part to satisfy a first arrangement; and / or the first transition part is connected between the second part and the third part. The first transition part enables the second part and the third part to satisfy a second arrangement.

[0012] Further, the first section includes a first part and a second part that form acute angles with the yoke in the radial direction, and the first part and the second part are connected; the structure of the second section is the same as that of the first section.

[0013] Further, the first section further includes a second transition part, which is connected to the first part and the second part, and the second transition part makes the included angle formed by the first part and the second part satisfy a preset angle.

[0014] Further, the circuit board includes an upper layer and a lower layer distributed along the axial direction of the yoke. The connection point of the first section and the second section is defined as a preset point. The coil section includes an upper section installed on the upper layer and a lower section installed on the lower layer. The first section includes a first upper sub-section with a distance from the preset point of zero to one-half of the preset width and a first lower sub-section with a distance from the preset point of one-half of the preset width to the preset width. The second section includes a second upper sub-section with a distance from the preset point of zero to one-half of the preset width and a second lower sub-section with a distance from the preset point of one-half of the preset width to the preset width. The first upper sub-section is connected to the second upper sub-section. The upper section includes the first upper sub-section and the second upper sub-section. The lower section includes the first lower sub-section and the second lower sub-section.

[0015] To achieve the above object, the present application adopts the following technical solutions: An eddy current sensor, which includes a mover and a coil assembly. The mover includes a plurality of second tooth parts, and the plurality of second tooth parts are evenly arranged along a preset linear direction. A second tooth slot is formed between adjacent two second tooth parts. Along the preset linear direction, the width of the second tooth slot is the same as the width of the second tooth part and is both defined as the second width; the coil assembly is located on one side of the plurality of second tooth parts along a first direction, and the first direction is perpendicular to the preset linear direction. The coil assembly includes a circuit board, a receiving coil, and an exciting coil. The receiving coil includes a cosine coil and a sine coil installed on the circuit board. The cosine coil includes a first coil and a second coil. The first coil includes a plurality of sequentially connected coil sections, and each coil section includes a first section and a second section. Along the preset linear direction, the width of the first section and the second section are both the second width. The first section and the second section are centrosymmetric structures with respect to their connection point. The first section and the second section are both composed of at least two wires extending in the linear direction; the second coil has the same structure as the first coil. When the second coil moves a distance of the second width along the preset linear direction, the second coil overlaps with the first coil along the first direction; the sine coil has the same structure as the cosine coil. When the sine coil moves a distance of one-half of the second width along the preset linear direction, the sine coil overlaps with the cosine coil along the first direction; the exciting coil is installed on the circuit board and is arranged around the receiving coil.

[0016] Further, the first section includes a first part and a second part extending along a second direction and a third part extending along a preset straight line direction, and the first part, the third part and the second part are connected in sequence; the second direction is perpendicular to the first direction and perpendicular to the preset straight line direction; or, the first section includes a first part forming an acute angle with the second direction, a second part forming an acute angle with the second direction and a third part extending along the preset straight line direction, and the first part, the third part and the second part are connected in sequence; or, the first section includes a first part forming an acute angle with the second direction and a second part forming an acute angle with the second direction, and the first part and the second part are connected; the structure of the second section is the same as that of the first section.

[0017] The cosine coil of the eddy current sensor described above includes a first coil and a second coil. The first coil includes a plurality of coil segments connected in sequence. Each coil segment includes a first section and a second section. Both the first section and the second section are composed of at least two wires extending along a straight line direction; the structure of the second coil is the same as that of the first coil, and the structure of the sine coil is the same as that of the cosine coil. Thus, by adjusting the length and angle of the wires of each coil segment, when the volume of the eddy current sensor is fixed, the number of pole pairs of the eddy current sensor can be increased, the number of turns per phase can be increased, and the effective induction area can be increased, thereby improving the resolution, signal-to-noise ratio and anti-interference ability of the eddy current sensor. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the eddy current sensor provided by an embodiment of the present application.

[0019] Figure 2 It is a front view of the eddy current sensor provided by an embodiment of the present application.

[0020] Figure 3 For an embodiment of the present application Figure 2 The partial enlarged view at A in the figure.

[0021] Figure 4 It is a structural cross-sectional view of the circuit board and the coil assembly of the eddy current sensor provided by an embodiment of the present application.

[0022] Figure 5 It is another angle structural cross-sectional view of the circuit board and the coil assembly of the eddy current sensor provided by an embodiment of the present application.

[0023] Figure 6 It is a schematic structural diagram of the first cosine coil of the eddy current sensor provided by an embodiment of the present application.

[0024] Figure 7 It is a schematic diagram of the induced voltage and the envelope line of the cosine coil of the eddy current sensor provided by an embodiment of the present application.

[0025] Figure 8Schematic diagram of the induced voltages of the cosine coil and sine coil of the eddy current sensor provided by the embodiments of the present application.

[0026] Figure 9 Schematic diagram of the structure of the second cosine coil of the eddy current sensor provided by the embodiments of the present application.

[0027] Figure 10 Schematic diagram of the structure of the third cosine coil of the eddy current sensor provided by the embodiments of the present application.

[0028] Figure 11 Schematic diagram of the structure of the coil segment of the eddy current sensor provided by the embodiments of the present application.

[0029] Figure 12 Schematic diagram of the structure of another eddy current sensor provided by the embodiments of the present application.

[0030] Figure 13 Schematic diagram of the structure of the first cosine coil of another eddy current sensor provided by the embodiments of the present application.

[0031] Figure 14 Schematic diagram of the structure of the second cosine coil of another eddy current sensor provided by the embodiments of the present application.

[0032] Figure 15 Schematic diagram of the structure of the third cosine coil of another eddy current sensor provided by the embodiments of the present application. Detailed implementation manners

[0033] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the specific embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0034] It should be noted that the "first", "second" and similar terms used in the specification and claims of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but indicate that there is at least one. "Multiple" or "several" means at least two. Unless otherwise specified, terms such as "front", "rear", "left", "right", "lower" and / or "upper" are only for convenience of description and are not limited to a position or a spatial orientation. Terms such as "including" or "comprising" mean that the elements or objects appearing before "including" or "comprising" cover the elements or objects listed after "including" or "comprising" and their equivalents, and do not exclude other elements or objects. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0035] As used in the specification and appended claims of the present application, the singular forms "a", "said", and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0036] As Figure 1 and Figure 2 shown, the present application provides an eddy current sensor 100, which can achieve the measurement of the absolute angular position of a rotating component. For example, the eddy current sensor 100 can achieve the measurement of the absolute angular position of a motor rotor.

[0037] Wherein, the eddy current sensor 100 includes a rotor 11 and a coil assembly 12. When the eddy current sensor 100 detects the absolute angular position of a motor, the rotor 11 is fixed to the rotor of the motor; when the eddy current sensor 100 detects the absolute angular position of other rotating components, the rotor 11 is fixed to the rotating component. The coil assembly 12 is located on one side of the rotor 11 and has a preset interval from the rotor 11, and this preset interval enables the coil assembly 12 to cooperate with the rotor 11 to achieve non-contact measurement.

[0038] As Figures 1 to 3 shown, specifically, the rotor 11 includes a yoke portion 111 and a plurality of tooth portions 112, and the yoke portion 111 and the plurality of tooth portions 112 are integrally formed. Among them, the yoke portion 111 has an annular structure, and each tooth portion 112 extends along the radial direction of the yoke portion 111, and the plurality of tooth portions 112 are evenly distributed on the outer peripheral surface of the yoke portion 111, so that the rotor 11 is basically in a gear-like structure and makes the rotor 11 more stable when rotating. A tooth groove 113 is formed between two adjacent tooth portions 112. Along the circumferential direction of the yoke portion 111, the width of the tooth groove 113 is the same as the width of the tooth portion 112 and is both defined as a preset width D1. It should be noted that the distance along the circumferential direction of the yoke portion 111 between the middle positions of the tooth portions 112 is the above-mentioned preset width D1, and the distance along the circumferential direction of the yoke portion 111 between the middle positions of the tooth grooves 113 is the above-mentioned preset width D1; a cylindrical surface 101 having the same axis as the yoke portion 111 is defined, and the cylindrical surface 101 divides the tooth portion 112 along the radial direction of the yoke portion 111 into two parts with basically the same length, and the intersection point of the cylindrical surface 101 and the tooth portion 112 is the middle position of the tooth portion 112, and the intersection point of the cylindrical surface 101 and the tooth groove 113 is the middle position of the tooth groove 113.

[0039] It should be noted that the preset width D1 is essentially an arc length on the cylindrical surface 101. If the number of pole pairs of the eddy current sensor 100 is set as p, then the central angle corresponding to the preset width D1 is π / p.

[0040] As Figures 2 to 5As shown, specifically, the coil assembly 12 is located on one side of the rotor 11 along the axial direction of the yoke 111. Among them, the coil assembly 12 includes a circuit board 121, a receiving coil 122, and an exciting coil 123. The exciting coil 123 can conduct high-frequency alternating current to generate an exciting magnetic field; the receiving coil 122 can sense the change of the magnetic field and output an induced voltage. The receiving coil 122 and the exciting coil 123 are both mounted on the circuit board 121, and the exciting coil 123 is arranged around the receiving coil 122. In this application, the exciting coil 123 is substantially circular, and the axis of the exciting coil 123 coincides with the axis of the yoke 111 substantially.

[0041] It should be noted that in this application, the circuit board 121 can be a PCB (Printed Circuit Board).

[0042] In this embodiment, the receiving coil 122 includes a cosine coil 200 and a sine coil 1221, and both the cosine coil 200 and the sine coil 1221 are mounted on the circuit board 121.

[0043] It should be noted that the receiving coil 122 needs to meet the following constraint conditions: (1) The number of pole pairs of the eddy current sensor 100 is p, and both the cosine coil 200 and the sine coil 1221 include n groups of coils, where n is an integer greater than or equal to 1, and each group of coils includes 2 turns of coils; the above 2 turns of coils have a total of p cycles on the circumference, and the central angle corresponding to one cycle is θturn = 2π / p. Among them, the definition of the cycle will be described below and will not be elaborated here.

[0044] (2) The circuit board 121 includes an upper layer 1211 and a lower layer 1212 distributed along the axial direction of the yoke 111. The above 2 turns of coils are distributed in a segmented and spaced manner on the upper layer 1211 and the lower layer 1212 of the circuit board 121 (that is, two adjacent segments are located on the upper layer 1211 and the lower layer 1212 respectively), and the central angle corresponding to each segment is θset = π / p. Adjacent segments are connected through the via holes 1213 on the circuit board 121. Among them, the definition of adjacent segments will be described below and will not be elaborated here.

[0045] (3) The above 2 turns of coils are exactly the same, only having a phase difference of π / p.

[0046] (4) The above 2 turns of coils are reversely connected in series through wiring on the circuit board 121 (two coils of the same specification are combined in the opposite direction (clockwise + counterclockwise), and are electrically connected in series to form a differential pair).

[0047] (5) If the cosine coil 200 and the sine coil 1221 include a number of turns n greater than 1, the phase difference between each group of coils is θset / 2n, and each group of coils is connected in series forward through wiring on the circuit board 121 (two coils of the same specification are combined in the same direction (both clockwise or counterclockwise), electrically connected in series to form signal superposition).

[0048] (6) The phase difference between the cosine coil 200 and the sine coil 1221 is θset / 2, and the cosine coil 200 and the sine coil 1221 are electrically insulated from each other.

[0049] (7) The rotor 11 is made of a metal material, and the structure of the rotor 11 is gear-shaped. The central angle corresponding to the tooth part 112 is θset = π / p, and the central angle corresponding to the tooth groove 113 is θset = π / p. The dimensional requirement of the tooth groove 113 in the radial direction of the yoke part 111 is: the projection of the induction area of the receiving coil 122 is located within the projection of the tooth groove 113 part.

[0050] (8) The excitation coil 123 is circular and is located on the upper layer 1211 or the lower layer 1212 of the circuit board 121. The radius of the excitation coil 123 is greater than the maximum distance between the receiving coil 122 and the axis of the yoke part 111, and the minimum distance between the excitation coil 123 and the receiving coil 122 is close to the minimum line distance required by the circuit board 121.

[0051] Through the above settings, the eddy current sensor 100 of the present application can perform the same measurement function as the eddy current sensor 100 with a sinusoidal trace.

[0052] It should be noted that the central angle corresponding to the preset width D1 is the above θset = π / p.

[0053] As Figure 3 and Figure 6 shown, as an implementation manner, the cosine coil 200 includes a first coil 21 and a second coil 22. It should be noted that the two turns of the cosine coil 200 in the above constraint conditions are the first coil 21 and the second coil 22; and as in the above constraint condition (1), the cosine coil 200 may include n groups of coils, and each group of coils includes a first coil 21 and a second coil 22.

[0054] Among them, the first coil 21 includes a plurality of sequentially connected coil segments 211. Each coil segment 211 includes a first segment 2111 and a second segment 2112. Along the circumferential direction of the yoke portion 111, the widths of both the first segment 2111 and the second segment 2112 are a preset width D1. Among them, the cylindrical surface 101 also passes through the connection point of the first segment 2111 and the second segment 2112. The first segment 2111 and the second segment 2112 are respectively located on both sides of the cylindrical surface 101, that is, the first segment 2111 and the second segment 2112 are respectively located on the inner side and the outer side of the cylindrical surface 101. Secondly, the diameter of the yoke portion 111 passing through the connection point of the first segment 2111 and the second segment 2112 is defined as a preset diameter 103. The first segment 2111 and the second segment 2112 are respectively located on both sides of the preset diameter 103, that is, the first segment 2111 and the second segment 2112 are respectively located on both sides of the preset diameter 103 along the circumferential direction of the yoke portion 111. Specifically, both the first segment 2111 and the second segment 2112 are composed of at least two wires extending in a straight line direction. It should be noted that each coil segment 211 forms a period, that is, the central angle corresponding to each coil segment 211 is θturn = 2π / p; the central angles corresponding to the first segment 2111 and the second segment 2112 are θset = π / p, so as to satisfy the above constraint condition (1).

[0055] Through the above settings, each period of the first coil 21 (that is, each coil segment 211) can be composed of one or more wire segments, and each wire segment extends in a straight line direction. The length of each wire segment and the angle between multiple wire segments can be adjusted according to actual situations. The above settings enable each wire segment of the coil segment 211 of the present application to have a design freedom degree, which refers to that the length of each wire segment in the first segment 2111 and the second segment 2112 and the inclination angle relative to the radial direction of the yoke portion 111 can be adjusted, so that the structural flexibility and deformability of the coil segment 211 are relatively high. Therefore, compared with the current sinusoidal-wiring eddy current sensor, the eddy current sensor 100 of the present application is more suitable for adjusting the effective induction area utilization rate, the number of turns per phase, and the number of pole pairs according to actual situations, and has a higher designable maximum effective induction area utilization rate, designable maximum number of turns per phase, and designable maximum number of pole pairs, thereby improving the resolution, signal-to-noise ratio, and anti-interference ability of the eddy current sensor 100.

[0056] For example, by adjusting the inclination angle of the wires in the first section 2111 and the second section 2112 relative to the radial direction of the yoke 111, the projections of the induction regions of the first section 2111 and the second section 2112 can be made into different shapes, thereby increasing the utilization rate of the effective induction area; by adjusting the included angle and length between the wires in the first section 2111 and the second section 2112, the shape of each coil section 211 can be adapted to the wiring density brought about by the increase in the number of turns of the first coil 21, so as to obtain a higher maximum number of turns per phase that can be designed; by overall adjusting the preset width D1 of each coil section 211, the number of pole pairs of the eddy current sensor 100 can be increased to adapt to different application requirements and detection requirements.

[0057] It should be noted that if it is necessary to increase the number of poles of the eddy current sensor 100 (such as applied to a multi-pole motor) or the number of turns per phase (such as the need to increase the output signal amplitude) due to application scenarios, the coil with a sinusoidal wiring is often difficult to meet the multi-pole design with pole number matching or the dense design with a large number of turns per phase under certain dimensions, resulting in a multiple loss of the electrical angle measurement resolution of the motor or the output signal amplitude and its signal-to-noise ratio not meeting the detection requirements. In this application, since each wire segment of the coil section 211 of this application has a design freedom, the structural flexibility and deformability of the coil section 211 are relatively high. Through the adjustment embodiments given in this application but not limited to them, the highest number of pole pairs and the highest number of turns per phase of the eddy current sensor 100 of this application can be increased. That is, compared with the coil with a sinusoidal wiring, the resolution, signal-to-noise ratio and anti-interference ability of the eddy current sensor 100 of this application are improved.

[0058] In this embodiment, the structure of the second coil 22 is the same as that of the first coil 21. When the second coil 22 moves a distance of the preset width D1 along the circumferential direction of the yoke 111, the second coil 22 and the first coil 21 overlap axially along the yoke 111. That is, the above constraint condition (2) is satisfied: "The two-turn coils are exactly the same, and there is only a phase difference of π / p".

[0059] Among them, the beneficial effects brought by the second coil 22 are basically the same as those brought by the first coil 21, and will not be elaborated here.

[0060] It should be noted that the first coil 21 and the second coil 22 enable the length of each wire segment of the cosine coil 200 and the angle between multiple wire segments to be adjusted according to the actual situation, so that the number of pole pairs of the eddy current sensor 100 can be increased, the number of turns per phase can be increased, and the utilization rate of the effective induction area can be increased. Furthermore, the resolution, signal-to-noise ratio and anti-interference ability of the eddy current sensor 100 can be improved.

[0061] In this embodiment, the sine coil 1221 has the same structure as the cosine coil 200. When the sine coil 1221 moves a distance equal to half of the preset width D1 along the circumferential direction of the yoke 111, the sine coil 1221 and the cosine coil 200 overlap axially along the yoke 111. That is, the above-mentioned constraint condition (6) is satisfied: the phase difference between the cosine coil 200 and the sine coil 1221 is θset / 2. At the same time, the sine coil 1221 and the cosine coil 200 are electrically insulated from each other.

[0062] Among them, the beneficial effects brought by the sine coil 1221 are basically the same as those brought by the cosine coil 200, and will not be elaborated here.

[0063] It should be noted that the sine coil 1221 and the cosine coil 200 enable the length of each wire segment of the receiving coil 122 and the angle between multiple wire segments to be adjusted according to actual conditions, so that the number of pole pairs of the eddy current sensor 100 can be increased, the number of turns per phase of the receiving coil 122 can be increased, and the utilization rate of the effective induction area can be increased. Furthermore, the resolution, signal-to-noise ratio, and anti-interference ability of the eddy current sensor 100 can be improved.

[0064] It should be noted that different from the existing sine-shaped wiring technology, the constraint conditions (1) to (8) extend the wiring shape of the receiving coil 122 of the eddy current sensor 100 from the existing sine shape to an arbitrary shape: for the wiring of the receiving coil 122 with an arbitrary shape, satisfying the above constraint conditions is a necessary and sufficient condition for the eddy current sensor 100 of the present application to perform the same measurement function as the existing sine-shaped wiring eddy current sensor. Based on the above constraint conditions, using the design freedom brought by the technical solution of the present application, the wiring shape of the receiving coil 122 can be designed. When the volume of the eddy current sensor 100 is certain, the number of pole pairs of the eddy current sensor 100 can be increased, the number of turns per phase can be increased, and when the width of the induction area is certain, the maximum effective induction area can be obtained, thereby improving the resolution, signal-to-noise ratio, and anti-interference ability of the eddy current sensor 100.

[0065] As Figure 7 and Figure 8 shown, as an implementation, the cosine coil 200 can generate a sine envelope waveform signal, and the sine coil 1221 can generate a cosine envelope waveform signal. It can be seen from this that the eddy current sensor 100 of the present application can perform the same measurement function as the eddy current sensor 100 with sine-shaped wiring.

[0066] As Figure 6As shown, as an alternative implementation, the first segment 2111 includes a first portion 2111a and a second portion 2111b that extend radially along the yoke 111, and a third portion 2111c that extends perpendicular to the radial direction of the yoke 111. That is, both the first portion 2111a and the second portion 2111b extend along a straight line, and when the number of coil segments 211 is large enough, the first portion 2111a and the second portion 2111b can be considered substantially parallel.

[0067] Among them, the first portion 2111a, the third portion 2111c, and the second portion 2111b are connected in sequence; the structure of the second segment 2112 is substantially the same as the structure of the first segment 2111. Through the above settings, the projection M1 of the induction area of the first segment 2111 can be substantially a rectangular structure, and the projection M2 of the induction area of the second segment 2112 can be substantially a rectangular structure. It should be noted that the structure of the second segment 2112 being substantially the same as the structure of the first segment 2111 means that there are minor differences between the two. The difference between the two structures lies in that: the second segment 2112 includes a corresponding portion corresponding to the third portion 2111c, and the length of the corresponding portion is less than the length of the third portion 2111c, that is, the difference between the second segment 2112 and the first segment 2111 is only in the length of the corresponding portion and the third portion 2111c.

[0068] It should be noted that this implementation can obtain the maximum effective induction area under a certain induction area width, that is, this implementation can maximize the utilization rate of the effective induction area, thereby improving the output signal amplitude, waveform quality, signal-to-noise ratio, and anti-interference ability of the eddy current sensor 100.

[0069] As Figure 9 shown, as an alternative implementation, for Figure 6 a simple deformation of the implementation shown to demonstrate one of the design freedoms brought by the technical solution of the present application. The first segment 2111 includes a first portion 2111a that forms an acute angle α with the radial direction of the yoke 111, a second portion 2111b that forms an acute angle β with the radial direction of the yoke 111, and a third portion 2111c that extends perpendicular to the radial direction of the yoke 111. That is, both the first portion 2111a and the second portion 2111b extend along a straight line, and an included angle is formed between the first portion 2111a and the second portion 2111b. It should be noted that the acute angle α formed by the first portion 2111a and the radial direction of the yoke 111 can be equal to the acute angle β formed by the second portion 2111b and the radial direction of the yoke 111, or the acute angle α formed by the first portion 2111a and the radial direction of the yoke 111 can be different from the acute angle β formed by the second portion 2111b and the radial direction of the yoke 111, that is, the positions of the first portion 2111a and the second portion 2111b can be adjusted according to the actual situation.

[0070] Among them, the first part 2111a, the third part 2111c and the second part 2111b are connected in sequence; the structure of the second section 2112 is basically the same as that of the first section 2111. Through the above settings, the projection M1 of the sensing area of ​​the first section 2111 can be basically a trapezoidal structure, and the projection M2 of the sensing area of ​​the second section 2112 can be basically a trapezoidal structure. It should be noted that the structure of the second section 2112 is basically the same as that of the first section 2111, which means that there are minor differences between the two. The difference between the two structures is that the second section 2112 includes a corresponding part corresponding to the third part 2111c, and the length of the corresponding part is less than the length of the third part 2111c, that is, the difference between the second section 2112 and the first section 2111 is only the difference in the length of the corresponding part and the third part 2111c.

[0071] like Figure 6 and Figure 9 As shown, in the above two embodiments, the first section 2111 also includes a first transition portion 2111d, the first transition portion 2111d extends along a straight line, the first transition portion 2111d is connected between the first portion 2111a and the third portion 2111c, and the first transition portion 2111d makes the first portion 2111a and the third portion 2111c satisfy the first arrangement mode; and / or the first transition portion 2111d is connected between the second portion 2111b and the third portion 2111c, and the first transition portion 2111d makes the second portion 2111b and the third portion 2111c satisfy the second arrangement mode. The first arrangement mode, i.e., the arrangement angle and arrangement position between the first part 2111a and the third part 2111c, meet the use requirements of the first section 2111, so that the first section 2111 can work normally; the second arrangement mode, i.e., the arrangement angle and arrangement position between the second part 2111b and the third part 2111c, meet the use requirements of the first section 2111, so that the first section 2111 can work normally. It should be noted that the normal operation of the first section 2111 above means that the first section 2111 of the cosine coil 200 will not conflict with the routing of the portion of the adjacent sine coil 1221 corresponding to the first section 2111, thereby avoiding the cosine coil 200 and the sine coil 1221 from being unable to route. The specific length, angle, and starting and ending positions of the first transition part 2111d are relatively freely adjustable, thereby further improving the design freedom of the cosine coil 200.

[0072] It should be noted that, under a certain sensing area width, by adjusting the specific length, angle, start and end positions of the first transition portion 2111d, Figure 6 The implementation shown in the figure obtains the maximum utilization rate of the effective sensing area. Specifically: Figure 3As shown, by adjusting the starting and ending positions of the first transition portion 2111d, shortening the length of the first transition portion 2111d, and adjusting the angle of the first transition portion 2111d, the starting and ending positions of the first transition portion 2111d are aligned with the via hole 1213 (refer to FIG. 1 ) on the circuit board 121 while meeting the minimum line spacing required by the circuit board 121. Figure 4 ) is the shortest. At this time, under a certain sensing area width, the effective sensing area of ​​the eddy current sensor 100 is the largest, that is, the utilization rate of the effective sensing area is maximized, thereby improving the output signal amplitude and waveform quality, signal-to-noise ratio and anti-interference of the eddy current sensor 100.

[0073] It should be noted that the first arrangement and the second arrangement can be adjusted according to actual needs, and this application does not limit them.

[0074] For example, the first arrangement can make the transition between the first portion 2111a and the third portion 2111c a non-right angle or non-sharp angle transition through the first transition portion 2111d, thereby avoiding signal interference caused by an increase in distributed capacitance of the wiring.

[0075] The second arrangement can make the transition between the second portion 2111b and the third portion 2111c a non-right angle or non-sharp angle transition through the first transition portion 2111d, thereby avoiding signal interference caused by an increase in distributed capacitance of the wiring.

[0076] like Figure 10 As shown, as another optional implementation, the first section 2111 includes a first portion 2111a that forms an acute angle Ω with the yoke 111 in the radial direction and a second portion 2111b that forms an acute angle γ with the yoke 111 in the radial direction, that is, the first portion 2111a and the second portion 2111b both extend along a straight line, and the first portion 2111a and the second portion 2111b form an angle. It should be noted that the acute angle Ω formed by the first portion 2111a and the yoke 111 in the radial direction can be equal to the acute angle γ formed by the second portion 2111b and the yoke 111 in the radial direction, and the acute angle Ω formed by the first portion 2111a and the yoke 111 in the radial direction can also be different from the acute angle γ formed by the second portion 2111b and the yoke 111 in the radial direction, that is, the positions of the first portion 2111a and the second portion 2111b can be adjusted according to actual conditions.

[0077] The first part 2111a and the second part 2111b are connected, and the structure of the second section 2112 is substantially the same as that of the first section 2111. Through the above configuration, the projection M1 of the sensing area of ​​the first section 2111 can be substantially a triangular structure, and the projection M2 of the sensing area of ​​the second section 2112 can be substantially a triangular structure.

[0078] It should be noted that the structure of the second section 2112 is basically the same as that of the first section 2111, which means that there are minor differences between the two. The difference between the two structures is that the first section 2111 also includes a second transition portion 2111e, which is connected to the first portion 2111a and the second portion 2111b, and the second transition portion 2111e makes the angle between the first portion 2111a and the second portion 2111b meet the preset angle. The preset angle can be adjusted according to actual needs, and this application does not limit it. The second section 2112 does not have the second transition portion 2111e.

[0079] It should be noted that the function of the second transition portion 2111e is substantially the same as that of the first transition portion 2111d, and will not be described in detail herein.

[0080] It should be noted that compared with the existing sinusoidal routing and other implementation methods of the present application, this implementation method is more conducive to designing a higher routing density, because the angle between the first part 2111a and the second part 2111b can be adjusted arbitrarily, and is more suitable for meeting the needs of increasing the number of pole pairs and the number of turns per phase. Therefore, when the volume of the eddy current sensor 100 is constant, the eddy current sensor 100 can have a larger maximum designable number of pole pairs and turns per phase, thereby improving the maximum pole pair number, resolution, signal-to-noise ratio and anti-interference performance of the adaptable motor of the eddy current sensor 100.

[0081] like Figure 5 and Figure 11 As shown, as an implementation, the circuit board 121 includes an upper layer 1211 distributed along the axial direction of the yoke 111 (refer to Figure 4 ) and lower layer 1212 (refer to Figure 5 ), the connection point between the first section 2111 and the second section 2112 is defined as a preset point 102. It should be noted that the preset point 102 is located on a cylindrical surface 101 coaxial with the yoke 111.

[0082] Specifically, the coil segment 211 includes an upper segment 2113 mounted on the upper layer 1211 and a lower segment 2114 mounted on the lower layer 1212. Among them, the first segment 2111 includes a first upper sub-segment 2111f with a distance from the preset point 102 being zero to one-half of the preset width D1 and a first lower sub-segment 2111g with a distance from the preset point 102 being one-half of the preset width D1 to the preset width D1. The second segment 2112 includes a second upper sub-segment 2112a with a distance from the preset point 102 being zero to one-half of the preset width D1 and a second lower sub-segment 2112b with a distance from the preset point 102 being one-half of the preset width D1 to the preset width D1. The first upper sub-segment 2111f is connected to the second upper sub-segment 2112a. The upper segment 2113 includes the first upper sub-segment 2111f and the second upper sub-segment 2112a. The lower segment 2114 includes the first lower sub-segment 2111g and the second lower sub-segment 2112b.

[0083] It should be noted that the upper segment 2113 and the first lower sub-segment 2111g are the "adjacent two segments" in the above-mentioned constraint condition (2), or the upper segment 2113 and the second lower sub-segment 2112b are the "adjacent two segments" in the above-mentioned constraint condition (2), so as to satisfy the above-mentioned constraint condition (2).

[0084] As Figure 12 and Figure 13 shown, the present application also provides another eddy current sensor 300, and this eddy current sensor 300 can measure the moving distance of a linear moving component. It should be noted that the linear moving component is any mechanism that can move along a straight line, such as a push rod, etc.

[0085] Among them, the eddy current sensor 300 includes a mover 31 and a coil assembly 32. When the eddy current sensor 300 detects the moving distance of the linear moving component, the mover 31 is fixed on the linear moving component. That is, in this embodiment, the eddy current sensor 300 does not include a rotor. The coil assembly 32 is located on one side of the mover 31 and has a preset interval from the mover 31, and this preset interval can enable the coil assembly 32 to cooperate with the mover 31 to achieve non-contact measurement.

[0086] Specifically, the mover 31 includes a plurality of second tooth portions 311, and the plurality of second tooth portions 311 are uniformly arranged along a preset straight line 301 direction. As an optional implementation manner, the plurality of second tooth portions 311 are fixed on the linear moving component and are uniformly arranged along the preset straight line 301 direction.

[0087] More specifically, a second tooth groove 312 is formed between two adjacent second tooth portions 311. Along the direction of the preset straight line 301, the width of the second tooth groove 312 is the same as that of the second tooth portion 311 and is defined as the second width D2. It should be noted that since multiple second tooth portions 311 are evenly arranged along the direction of the preset straight line 301, that is, multiple second tooth portions 311 are arranged at equal intervals along the direction of the preset straight line 301, the second width D2 is the width of the second tooth portion 311 along the direction of the preset straight line 301, and the second width D2 is the width of the second tooth groove 312 along the direction of the preset straight line 301.

[0088] Specifically, the coil assembly 32 is located on one side of multiple second tooth portions 311 along a first direction, and the first direction is perpendicular to the direction of the preset straight line 301. Among them, the coil assembly 32 includes a circuit board (not shown in the figure), a receiving coil 322, and an exciting coil 323. It should be noted that the receiving coil 322 of the coil assembly 32 in this embodiment is only different from the receiving coil 122 of the coil assembly 12 in the previous embodiment in the arrangement manner; the circuit board and the exciting coil 323 in this embodiment are basically the same as the circuit board 121 and the exciting coil 123 in the previous embodiment.

[0089] In this embodiment, the receiving coil 322 includes a cosine coil 400 and a sine coil 3221, and both the cosine coil 400 and the sine coil 3221 are mounted on the circuit board.

[0090] Among them, the cosine coil 400 includes a first coil 41 and a second coil 42. The first coil 41 includes multiple sequentially connected coil segments 411. Each coil segment 411 includes a first segment 4111 and a second segment 4112. Along the direction of the preset straight line 301, the widths of both the first segment 4111 and the second segment 4112 are the second width D2, and the first segment 4111 and the second segment 4112 are centrosymmetric structures with respect to the connection point between the two.

[0091] Specifically, both the first segment 4111 and the second segment 4112 are composed of at least two wires extending in a straight line direction.

[0092] With the above settings, each coil segment 411 of the first coil 41 can be composed of one or more segments of wire, and each segment of wire extends along a straight line direction. The length of each segment of wire and the angle between multiple segments of wire can be adjusted according to the actual situation. The above settings enable each segment of wire of the coil segment 411 in the present application to have a design freedom, which refers to the fact that the length and the inclination angle relative to the second direction 303 of each segment of wire in the first segment 4111 and the second segment 4112 can be adjusted, so that the structural flexibility and deformability of the coil segment 411 are relatively high. As a result, the eddy current sensor 300 in the present application is more suitable for adjusting the effective induction area utilization rate, the number of turns per phase, and the period length (i.e., the second width D2) according to the actual situation compared with the current sinusoidal-wiring eddy current sensor, and has a higher designable maximum effective induction area utilization rate, a designable maximum number of turns per phase, and a designable shortest period length, thereby improving the resolution, signal-to-noise ratio, and anti-interference ability of the eddy current sensor 300.

[0093] For example, by adjusting the inclination angles of the wires in the first segment 4111 and the second segment 4112 relative to the second direction 303, the projections of the induction regions of the first segment 4111 and the second segment 4112 can be made into different shapes to adapt to different application requirements and detection requirements. Among them, the second direction 303 is perpendicular to the first direction and perpendicular to the direction of the preset straight line 301.

[0094] In this embodiment, the structure of the second coil 42 is the same as that of the first coil 41. When the second coil 42 moves a distance of the second width D2 along the direction of the preset straight line 301, the second coil 42 overlaps with the first coil 41 along the first direction; the structure of the sine coil 3221 is the same as that of the cosine coil 400. When the sine coil 3221 moves a distance of half of the second width D2 along the direction of the preset straight line 301, the sine coil 3221 overlaps with the cosine coil 400 along the first direction.

[0095] Among them, the beneficial effects brought by the second coil 42 are basically the same as those brought by the first coil 41, and will not be elaborated here; the beneficial effects brought by the sine coil 3221 are basically the same as those brought by the cosine coil 400, and will not be elaborated here.

[0096] More specifically, the cosine coil 400 is the same as the cosine coil 200, and both can generate a cosine-sine envelope waveform signal. The sine coil 3221 is the same as the sine coil 1221, and both can generate a sine-cosine envelope waveform signal.

[0097] Such as Figure 13As shown, in this embodiment, exemplarily, the first section 4111 includes a first portion 4111a and a second portion 4111b extending along the second direction 303 and a third portion 4111c extending along the direction of the preset straight line 301, that is, the first portion 4111a and the second portion 4111b both extend along a straight line, and the first portion 4111a and the second portion 4111b are substantially parallel.

[0098] The first part 4111a, the third part 4111c and the second part 4111b are connected in sequence; the structure of the second section 4112 is consistent with the structure of the first section 4111. Through the above configuration, the projection M3 of the sensing area of ​​the first section 4111 can be basically a rectangular structure, and the projection M4 of the sensing area of ​​the second section 4112 can be basically a rectangular structure, and the projections of the sensing areas of the first section 4111 and the second section 4112 are centrally symmetrical structures about the connection point between the two.

[0099] like Figure 14 As shown, illustratively, the first section 4111 includes a first portion 4111a that forms an acute angle with the second direction 303, a second portion 4111b that forms an acute angle with the second direction 303, and a third portion 4111c that extends along the preset straight line 301, that is, the first portion 4111a and the second portion 4111b both extend along a straight line, and the first portion 4111a and the second portion 4111b form an angle. It should be noted that the acute angle formed by the first portion 4111a and the second direction 303 can be equal to the acute angle formed by the second portion 4111b and the second direction 303, and the acute angle formed by the first portion 4111a and the second direction 303 can also be different from the acute angle formed by the second portion 4111b and the second direction 303, that is, the positions of the first portion 4111a and the second portion 4111b can be adjusted according to actual conditions.

[0100] The first part 4111a, the third part 4111c and the second part 4111b are connected in sequence; the structure of the second section 4112 is consistent with the structure of the first section 4111. Through the above configuration, the projection M3 of the sensing area of ​​the first section 4111 can be basically a trapezoidal structure, and the projection M4 of the sensing area of ​​the second section 4112 can be basically a trapezoidal structure, and the projections of the sensing areas of the first section 4111 and the second section 4112 are centrally symmetrical structures about the connection point between the two.

[0101] It should be noted that in the above two embodiments, the first section 4111 also includes the same first transition portion 4111d as in the previous embodiment. The first transition portion 4111d has the same structure and effect as the first transition portion 2111d in the previous embodiment, and will not be described in detail here.

[0102] likeFigure 15 As shown, illustratively, the first section 4111 includes a first portion 4111a which is at an acute angle with the second direction 303 and a second portion 4111b which is at an acute angle with the second direction 303, that is, the first portion 4111a and the second portion 4111b both extend along a straight line, and the first portion 4111a and the second portion 4111b form an angle. It should be noted that the acute angle formed by the first portion 4111a and the second direction 303 may be equal to the acute angle formed by the second portion 4111b and the second direction 303, and the acute angle formed by the first portion 4111a and the second direction 303 may also be different from the acute angle formed by the second portion 4111b and the second direction 303, that is, the positions of the first portion 4111a and the second portion 4111b may be adjusted according to actual conditions.

[0103] The first part 4111a and the second part 4111b are connected; the structure of the second section 4112 is consistent with the structure of the first section 4111. Through the above configuration, the projection of the sensing area of ​​the first section 4111 can be basically a triangular structure, and the projection M3 of the sensing area of ​​the second section 4112 can be basically a triangular structure, and the projection M4 of the sensing area of ​​the first section 4111 and the second section 4112 are centrally symmetrical structures about the connection point between the two.

[0104] It should be noted that, in the above embodiment, the first section 4111 also includes the same second transition portion 4111e as in the previous embodiment. The second transition portion 4111e has the same structure and effect as the second transition portion 2111e in the previous embodiment, and will not be described in detail here.

[0105] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. An eddy current sensor, characterized in that: include: A rotor, the rotor comprising a yoke and a plurality of teeth, the yoke being in a circular ring structure, each of the teeth extending in a radial direction of the yoke, the plurality of teeth being evenly distributed on an outer peripheral surface of the yoke, a tooth groove being formed between two adjacent teeth, and a width of the tooth groove being consistent with a width of the teeth along the circumference of the yoke and both being defined as a preset width; A coil assembly, the coil assembly is located on one side of the rotor along the axial direction of the yoke, and the coil assembly includes: Circuit boards; A receiving coil, wherein the receiving coil comprises a cosine coil and a sine coil mounted on the circuit board, the cosine coil comprises a first coil and a second coil, the first coil comprises a plurality of coil segments connected in sequence, each of the coil segments comprises a first segment and a second segment, along the circumference of the yoke, the width of the first segment and the width of the second segment are both the preset width, a cylindrical surface coaxial with the yoke and passing through a connection point of the first segment and the second segment is defined, the first segment and the second segment are respectively located on both sides of the cylindrical surface, the diameter of the yoke passing through the connection point is defined as a preset diameter, the first segment and the second segment are respectively located on both sides of the preset diameter, the first segment and the second segment are both composed of at least two conducting wires extending in a straight line direction; the second coil has the same structure as the first coil, and when the second coil moves along the circumference of the yoke by a distance of the preset width, the second coil overlaps with the first coil axially along the yoke; the sine coil has the same structure as the cosine coil, and when the sine coil moves along the circumference of the yoke by a distance of half of the preset width, the sine coil overlaps with the cosine coil axially along the yoke; The exciting coil is mounted on the circuit board and is arranged around the receiving coil.

2. The eddy current sensor according to claim 1, characterized in that: The cosine coil can generate a sine envelope waveform signal, and the sine coil can generate a cosine envelope waveform signal.

3. The eddy current sensor according to claim 1, characterized in that: The first section includes a first part and a second part extending radially along the yoke and a third part extending radially perpendicular to the yoke, and the first part, the third part and the second part are connected in sequence; the structure of the second section is basically consistent with the structure of the first section.

4. The eddy current sensor according to claim 1, characterized in that: The first section includes a first part that forms an acute angle with the radial direction of the yoke, a second part that forms an acute angle with the radial direction of the yoke, and a third part that extends perpendicularly to the radial direction of the yoke, and the first part, the third part and the second part are connected in sequence; the structure of the second section is basically the same as the structure of the first section.

5. The eddy current sensor according to claim 3 or 4, characterized in that: The first section further includes a first transition portion, the first transition portion extends along a straight line, the first transition portion is connected between the first portion and the third portion, and the first transition portion enables the first portion and the third portion to meet a first arrangement mode; And / or the first transition portion is connected between the second portion and the third portion, and the first transition portion enables the second portion and the third portion to satisfy a second arrangement manner.

6. The eddy current sensor according to claim 1, characterized in that: The first section includes a first portion which forms an acute angle with the yoke in the radial direction and a second portion which forms an acute angle with the yoke in the radial direction, and the first portion and the second portion are connected; the structure of the second section is substantially consistent with that of the first section.

7. The eddy current sensor according to claim 6, characterized in that: The first section also includes a second transition portion, which is connected to the first portion and the second portion, and the second transition portion enables an angle between the first portion and the second portion to meet a preset angle.

8. The eddy current sensor according to claim 1, characterized in that: The circuit board includes an upper layer and a lower layer distributed axially along the yoke, and the connection point between the first segment and the second segment is defined as a preset point. The coil segment includes an upper segment installed on the upper layer and a lower segment installed on the lower layer. The first segment includes a first upper sub-segment whose distance from the preset point is zero to one-half of the preset width and a first lower segment whose distance from the preset point is one-half of the preset width to the preset width. The second segment includes a second upper sub-segment whose distance from the preset point is zero to one-half of the preset width and a second lower sub-segment whose distance from the preset point is one-half of the preset width to the preset width. The first upper sub-segment is connected to the second upper sub-segment. The upper segment includes the first upper sub-segment and the second upper sub-segment, and the lower segment includes the first lower sub-segment and the second lower sub-segment.

9. An eddy current sensor, characterized in that: include: A mover, wherein the mover comprises a plurality of second teeth, the plurality of second teeth are evenly arranged along a preset straight line direction, a second tooth groove is formed between two adjacent second teeth, and along the preset straight line direction, the width of the second tooth groove is consistent with the width of the second tooth and both are defined as the second width; A coil component, wherein the coil component is located on one side of the plurality of second teeth along a first direction, wherein the first direction is perpendicular to the preset straight line direction, and the coil component comprises: Circuit boards; A receiving coil, wherein the receiving coil comprises a cosine coil and a sine coil mounted on the circuit board, the cosine coil comprises a first coil and a second coil, the first coil comprises a plurality of coil segments connected in sequence, each of the coil segments comprises a first segment and a second segment, along the preset straight line direction, the width of the first segment and the width of the second segment are both the second width, the first segment and the second segment are centrally symmetrical about a connection point between the first segment and the second segment, and the first segment and the second segment are both composed of at least two conducting wires extending along a straight line direction; the second coil has the same structure as the first coil, and when the second coil moves along the preset straight line direction by a distance of the second width, the second coil overlaps with the first coil along the first direction; the sine coil has the same structure as the cosine coil, and when the sine coil moves along the preset straight line direction by a distance of half of the second width, the sine coil overlaps with the cosine coil along the first direction; The exciting coil is mounted on the circuit board and is arranged around the receiving coil.

10. The eddy current sensor according to claim 9, characterized in that: The first section includes a first portion and a second portion extending along a second direction and a third portion extending along the preset straight line direction, the first portion, the third portion and the second portion are sequentially connected; the second direction is perpendicular to the first direction and perpendicular to the preset straight line direction; Or, the first section includes a first portion forming an acute angle with the second direction, a second portion forming an acute angle with the second direction, and a third portion extending along the preset straight line direction, and the first portion, the third portion, and the second portion are sequentially connected; or, the first section includes a first portion forming an acute angle with the second direction, and a second portion forming an acute angle with the second direction, and the first portion and the second portion are connected; The structure of the second section is consistent with that of the first section.

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