Electromagnetic encoder and direction detection antenna

Abstract

The utility model provides an electromagnetic encoder and a direction detection antenna. The electromagnetic encoder comprises a control circuit, a direction detection antenna and a resonant circuit, the direction detection antenna is connected with the control circuit and comprises at least three mutually insulated detection coils, and the at least three detection coils are sequentially distributed along a preset direction to form an annular or semi-annular detection area; the resonance circuit is arranged opposite to the direction detection antenna and is arranged in a rotating mode on a preset track relative to the detection coils in the circumferential direction of the detection area, and at any rotating position, the inductance magnetic line of force of the resonance circuit penetrates through the at least two detection coils. According to the electromagnetic encoder of the utility model, the three detection coils form a detection area, the inductance magnetic line of force of the resonance circuit passes through the at least two detection coils at any rotation position, so that the signal amplitude of the at least two detection coils is obviously changed, and the rotation direction of the resonance circuit is confirmed according to the signal amplitude change of the detection coils. The structure is simple, and software algorithm requirements are met.

Description

Technical Field

[0001] The utility model relates to the field of encoders, in particular to an electromagnetic encoder and a direction detection antenna.

Background Art

[0002] An encoder is a device that converts angular displacement or linear displacement into an electrical signal. Existing encoders include optoelectronic encoders and electromagnetic encoders. Optoelectronic encoders use the principle of grating diffraction to achieve displacement-digital conversion, and through optoelectronic conversion, the mechanical speed on the output shaft is converted into a pulse digital quantity. However, optoelectronic encoders are sensitive to light and dust, have poor environmental adaptability, and use complex optical elements and high-precision manufacturing processes, resulting in high prices. In contrast, electromagnetic encoders are widely used in industrial production lines, machine tool processing, automation equipment, robots and other fields due to their strong environmental adaptability, simple structure and low cost.

[0003] Please refer to Figure 1 and Figure 2 , where Figure 1 is a schematic structural diagram of an electromagnetic encoder provided by the prior art, Figure 2 is Figure 1 a schematic structural diagram of the rotating unit and the antenna shown in . The electromagnetic encoder 10 provided by the prior art includes a rotating unit 11 and a transceiver unit 12. The rotating unit 11 includes an LC resonance circuit 111 and a runner 112, and the LC resonance circuit 111 is arranged on the runner 112. The transceiver unit 12 includes an antenna 121, a selection switch 122, a first amplifier 123, a second amplifier 124, a comparator 125, an MCU processor 126, a detector 128, a sample and hold circuit 129 and an antenna transmission signal driver 130. The antenna 121 is arranged under the runner 112 for transmitting an electromagnetic signal to the LC resonance circuit 111 and receiving the electromagnetic signal returned by the LC resonance circuit 111.

[0004] There are three groups of the LC resonance circuits 111, which are arranged around the runner 112 and have different resonance frequencies A, B, and C. When the antenna 121 rotates clockwise, a frequency signal of the ABCABCABC combination sequence will be received, and when the antenna 121 rotates counterclockwise, a frequency signal of the ACBACBACB combination sequence will be received. Therefore, according to the received frequency signal, the rotation information of the runner 112 can be determined.

[0005] However, the electromagnetic encoder 10 of the prior art needs to set three groups of LC resonance circuits 111 with different resonance frequencies, and needs to receive electromagnetic signals of different frequencies and accurately identify and distinguish them. The structure is relatively complex and the requirement for software algorithms is high.

Content of the Utility Model

[0006] In view of the technical problems of the complex structure of the electromagnetic encoder in the current prior art and the high requirements for software algorithms, the present utility model provides an electromagnetic encoder and a direction detection antenna for solving the above problems.

[0007] An embodiment of the present utility model provides an electromagnetic encoder, including a control circuit, a direction detection antenna and a resonant circuit. The direction detection antenna is electrically connected to the control circuit and includes at least three mutually insulated detection coils. At least three of the detection coils are sequentially distributed along a preset direction to form an annular or semi-annular detection area. The resonant circuit is disposed opposite to the direction detection antenna and rotates along a preset trajectory circumferentially relative to the detection coils in the detection area. At any rotation position of the projection of the resonant circuit in the detection area, the inductive magnetic force lines of the resonant circuit pass through at least two of the detection coils.

[0008] In some embodiments, at any rotation position of the projection of the resonant circuit in the detection area, there is an overlapping area with at least two of the detection coils.

[0009] In some embodiments, among three adjacent detection coils, the projection of the middle detection coil in the circumferential direction of the inner circle in the annular or semi-annular detection area is completely covered by the projections of the front and rear detection coils in the circumferential direction of the inner circle in the annular or semi-annular detection area.

[0010] In some embodiments, one end of the boundary line between two adjacent detection coils is located at the inner ring of the detection area, and the other end is located at the outer ring of the detection area. The projections of the two adjacent boundary lines in the circumferential direction of the inner circle in the annular or semi-annular detection area are connected or have an overlapping area.

[0011] In some embodiments, the detection area is annular, and each detection coil includes a first part and a second part. Along the preset direction, in two adjacent detection coils, the first part of the latter detection coil completely covers the second part of the former detection coil.

[0012] In some embodiments, it further includes a substrate. The substrate includes a via hole, a front surface and a back surface opposite to each other. The via hole communicates the front surface and the back surface. The first part is located on the front surface, the second part is located on the back surface, and the first part and the second part are connected through the via hole.

[0013] In some embodiments, at least three of the detection coils are correspondingly distributed to form at least three sub-detection regions. The shape of each sub-detection region is the same. The number of the detection coils is n. The central angle of the circle of the inner circle of the annular or semi-annular detection region between the centers of two adjacent sub-detection regions is α / n, and the central angle of the circle of the inner circle of the annular or semi-annular detection region of each sub-detection region is 2α / n, where n is an integer greater than or equal to 3, and α is the central angle of the detection region.

[0014] In some embodiments, at least three of the detection coils are correspondingly distributed to form at least three sub-detection regions. Each detection coil is a multi-turn coil wound by a wire and covers one sub-detection region.

[0015] An embodiment of the present invention provides a direction detection antenna, which includes at least three mutually insulated detection coils. The detection coils are sequentially distributed along a preset direction to form an annular or semi-annular detection region. Among three adjacent detection coils, the projection of the middle detection coil in the circumferential direction of the inner circle of the annular or semi-annular detection region is completely covered by the projections of the front and rear detection coils in the circumferential direction of the inner circle of the annular or semi-annular detection region.

[0016] In some embodiments, one end of the intersection line between two adjacent detection coils is located on the inner ring of the detection region, and the other end is located on the outer ring of the detection region. The projections of two adjacent intersection lines in the circumferential direction of the inner circle of the annular or semi-annular detection region are connected or have an overlapping region.

[0017] In some embodiments, the intersection point of the intersection line and the inner ring of the detection region is the inner-ring intersection point, and the intersection point of the intersection line and the outer ring of the detection region is the outer-ring intersection point. Along the preset direction, the straight line where the outer-ring intersection point of the previous intersection line and the inner-ring intersection point of the next intersection line are located passes through the center of the inner circle of the annular or semi-annular detection region.

[0018] In some embodiments, each detection coil includes a first part and a second part. Along the preset direction, among two adjacent detection coils, the first part of the latter detection coil completely covers the second part of the previous detection coil.

[0019] In some embodiments, the detection region is annular. Each detection coil includes a first part and a second part. Along the preset direction, among two adjacent detection coils, the second part of the previous detection coil completely overlaps with the first part of the latter detection coil.

[0020] In some embodiments, it further includes a substrate, the substrate includes vias, opposite front and back surfaces, the vias communicate the front and back surfaces, the first part is located on the front surface, the second part is located on the back surface, and the first part and the second part are connected through the vias.

[0021] In some embodiments, at least three of the detection coils are correspondingly distributed to form at least three sub-detection regions, the shape of each sub-detection region is the same, the number of the detection coils is n, the central angle of adjacent two sub-detection regions relative to the center of the inner circle of the annular or semi-annular detection region is α / n, and the central angle of each sub-detection region relative to the center of the inner circle of the annular or semi-annular detection region is 2α / n, where n is an integer greater than or equal to 3, and α is the central angle of the detection region.

[0022] In some embodiments, at least three of the detection coils are correspondingly distributed to form at least three sub-detection regions, and each detection coil is a multi-turn coil wound by a wire, covering one sub-detection region.

[0023] Compared with the prior art, in the electromagnetic encoder of the present utility model, three mutually insulated detection coils are arranged along a preset direction to form an annular or semi-annular detection region, the resonant circuit and the direction detection antenna are arranged to rotate relative to each other, the projection of the resonant circuit on the detection region is at any rotation position, the inductive magnetic force lines of the resonant circuit pass through at least two of the detection coils, thereby causing obvious changes in the signal amplitudes of at least two of the detection coils, and thus confirming the rotation direction of the resonant circuit according to the changes in the signal amplitudes of the detection coils. There is no need to set multiple resonant circuits with different frequencies, the structure is simple, and only the amplitude changes of the detection coils need to be detected and calculated, and the requirement for the software algorithm is low.

Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings, where:

[0025] Figure 1 is a connection schematic diagram of an electromagnetic encoder provided by the prior art;

[0026] Figure 2 is Figure 1 the structural schematic diagram of the rotation unit and the antenna shown;

[0027] Figure 3 is a connection schematic diagram of an electromagnetic encoder provided by an embodiment of the present utility model;

[0028] Figure 4 is a schematic structural diagram of a direction detection antenna provided by the first embodiment of the present utility model;

[0029] Figure 5 is another schematic structural diagram of a direction detection antenna provided by the first embodiment of the present utility model;

[0030] Figure 6 is yet another schematic structural diagram of a direction detection antenna provided by the first embodiment of the present utility model;

[0031] Figure 7A and 7B and 7C are schematic structural diagrams of a direction detection antenna provided by the second embodiment of the present utility model;

[0032] Figure 8 is a side view schematic diagram of another direction detection antenna provided by the second embodiment of the present utility model;

[0033] Figure 9, 9A, 9B, 9C, 9D are schematic structural diagrams of yet another direction detection antenna provided by the second embodiment of the present utility model;

[0034] Figure 10 is a side view schematic diagram of still another direction detection antenna provided by the second embodiment of the present utility model;

[0035] Figure 11 is a schematic structural diagram of a direction detection antenna provided by the third embodiment of the present utility model.

Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0037] Please refer to Figure 3, which is a schematic structural diagram of an electromagnetic encoder disclosed in an embodiment of the present invention. The electromagnetic encoder 20 includes a control circuit 21, a direction detection antenna 23, a resonant circuit 26, and a knob 27. The control circuit 21 is electrically connected to the direction detection antenna 23. The direction detection antenna 23 includes at least three mutually insulated detection coils 231. At least three of the detection coils 231 are sequentially distributed along a preset direction to form an annular or semi-annular detection area. At least three of the detection coils 231 are correspondingly distributed to form at least three sub-detection areas. Each of the detection coils 231 is a multi-turn coil wound by a wire, covering one of the sub-detection areas. The head and tail ends of the wire are led out and electrically connected to the control circuit 21. The resonant circuit 26 is disposed on the knob 27 and is disposed opposite to the direction detection antenna 23, so that the magnetic force lines of the resonant circuit 26 pass through the detection coils 231. And the resonant circuit 26 is rotatably disposed along the circumferential direction of the detection area relative to the detection coils 231 on a preset track. At any rotation position of the projection of the resonant circuit 26 in the detection area, the inductive magnetic force lines of the resonant circuit 26 pass through at least two of the detection coils 231.

[0038] It can be understood that the any rotation position refers to the rotation position on the preset track. The preset track is an effective rotation range area or a range area smaller than the rotation range area set as needed. For example, when the detection area is semi-annular, the other half ring of the circle where the detection area is located does not belong to the effective range area. Those skilled in the art can also set only a part of the detection area as the preset track as needed. The semi-annular shape can be a semi-ring with a central angle less than 360°, not limited to a semi-ring with a central angle equal to 180°.

[0039] The control circuit 21 includes a switch 211, a receiving unit 212, and a control unit 213. The control unit 213 controls the detection coils 231 to receive and process the electromagnetic signals sent by the resonant circuit 26 through the receiving unit 212 and the switch 211. When the knob 27 rotates, the resonant circuit 26 rotates accordingly. The projection of the resonant circuit 26 in the detection area moves from one detection coil 231 to another detection coil 231. The magnetic force lines passing through the previous detection coil 231 become fewer, and the trend of the signal amplitude received by the previous detection coil 231 decreases. The magnetic force lines passing through the latter detection coil 231 become more, and the trend of the signal amplitude received by the latter detection coil 231 increases. The control unit 213 can confirm the rotation direction of the knob 27 according to the amplitude change of the signals received by the detection coils 231.

[0040] Preferably, the projection of the resonant circuit 26 on the detection area overlaps with at least two of the detection coils 231 at any rotation position. The signal of the detection coil 231 with an overlapping area is the strongest, and the signal detection is accurate. The rotation direction of the knob 27 can be determined by comparing the signal amplitude changes of the detection coils 231 with larger signal amplitudes, improving the detection accuracy.

[0041] Among them, the preset direction can be the clockwise direction or the counterclockwise direction.

[0042] It should be noted that the receiving unit 212 can also be provided with a signal transmitter to transmit an electromagnetic signal to the resonant circuit 26 to energize the resonant circuit 26. The resonant circuit 26 can also be a self-excited oscillation circuit without being energized by the receiving unit 212. Those skilled in the art can set it according to actual needs and will not be specifically limited here.

[0043] Compared with the prior art, in the electromagnetic encoder 20 of the present invention, three mutually insulated detection coils 231 are arranged along a preset direction to form an annular or semi-annular detection area. The resonant circuit 26 and the direction detection antenna 23 are rotatably arranged relative to each other. At any rotation position of the projection of the resonant circuit 26 on the detection area, the inductive magnetic force lines of the resonant circuit 26 pass through at least two of the detection coils 231, thereby causing obvious changes in the signal amplitudes of at least two of the detection coils 231. Thus, the rotation direction of the knob 27 is confirmed according to the signal amplitude changes of the detection coils 231. There is no need to set multiple resonant circuits with different frequencies, the structure is simple, and only the amplitude changes of the detection coils 231 need to be detected and calculated, with low requirements for software algorithms.

[0044] First Embodiment

[0045] Please refer to Figure 4 , which is a schematic structural diagram of a direction detection antenna provided by the first embodiment of the present invention. The direction detection antenna 23 includes n mutually insulated detection coils 231a and a substrate 233a, and the detection coils 231a are arranged on the substrate 233a. Among three adjacent detection coils 231a, the projection of the middle detection coil 231a in the circumferential direction on the inner circle of the annular or semi-annular detection area is completely covered by the projections of the front and rear two detection coils 231a on the circle where the detection area is located. Specifically, one end of the intersection line of two adjacent detection coils 231a is located at the inner ring of the detection area, and the other end is located at the outer ring of the detection area. The projection of the intersection line of two adjacent detection coils 231a in the circumferential direction on the inner circle of the annular or semi-annular detection area is connected or has an overlapping area, where n≥3 and n∈Z.

[0046] Therefore, when the resonant circuit 26 rotates relative to the detection coil 231a along the circumference of the detection area, it will inevitably reach the beginning of the next boundary line when it reaches the end of the previous boundary line. That is, when the resonant circuit 26 rotates on the boundary line, the projection of the resonant circuit 26 on the detection area will inevitably have an overlapping area with the two detection coils 231a forming the boundary line at any rotation position.

[0047] It should be noted that the detection coil 231a can be arranged on one side surface or both sides surface of the substrate 233a. For example, the same detection coil 231a can be partially arranged on one side surface of the substrate 233a, and the other part can be arranged on the other side surface of the substrate 233a. A hole is opened on the substrate 233a, and the parts of the detection coil 231a are interconnected through the hole. For multiple detection coils 231a, part of the detection coils 231a can be arranged on one side surface of the substrate 233a, and the other part of the detection coils 231a can be arranged on the other surface of the substrate 233a.

[0048] It can be understood that the projections of the n mutually insulated detection coils 231a in the circumferential direction of the inner circle of the annular or semi-annular detection area correspondingly form an annular or semi-annular shape.

[0049] The situation where the boundary line of two adjacent detection coils 231a is connected to the projection of the inner circle of the annular or semi-annular detection area in the circumferential direction is specifically described as follows:

[0050] The intersection point of the boundary line AB between two adjacent detection coils 231a and the inner ring of the detection area is the inner ring intersection point A, and the intersection point of the boundary line AB between two adjacent detection coils 231a and the outer ring of the detection area is the outer ring intersection point B. The straight line connecting the inner ring intersection point A and the outer ring intersection point B on the same boundary line AB does not pass through the center of the inner circle of the annular or semi-annular detection area. Along the preset direction, the previous boundary line A m-1 B m-1 The outer ring intersection point B m-1 The boundary line A m B m The inner ring intersection point A m The straight line where it is located passes through the center of the inner circle of the annular or semi-annular detection area. Wherein, n≥3, and n∈Z, n≥m≥2, m∈Z.

[0051] Therefore, when the resonant circuit 26 rotates relative to the detection coil 231a along the circumference of the detection area, it reaches the previous boundary line A. m-1 B m-1 At the same time as the end, it reaches the next intersection line A m Bm The start.

[0052] It should be noted that at least three sub - detection regions formed by the corresponding distribution of at least three of the detection coils 231a may have the same or different shapes for each sub - detection region, and those skilled in the art can set them according to actual needs. When the shapes of each sub - detection region are the same, the central angle of two adjacent sub - detection regions with respect to the center of the inner circle of the annular or semi - annular detection region is α / n, and the central angle of each sub - detection region with respect to the center of the inner circle of the annular or semi - annular detection region is 2α / n, where α is the central angle of the detection region. When the detection region is annular, α = 360°. For example, if the detection region is annular and n = 3, the central angle of two adjacent sub - detection regions with respect to the center of the inner circle of the annular detection region is 120°, and the central angle of each sub - detection region with respect to the center of the inner circle of the annular detection region is 240°, as shown in Figure 4 ; if the detection region is annular and n = 4, the central angle of two adjacent sub - detection regions with respect to the center of the inner circle of the annular detection region is 90°, and the central angle of each sub - detection region with respect to the center of the inner circle of the annular detection region is 180°, as shown in Figure 5 .

[0053] The situation where the projection of the intersection line between two adjacent detection coils 231a in the circumferential direction of the inner - circle circumference of the annular or semi - annular detection region has an overlapping area is specifically described as follows:

[0054] The intersection point of the intersection line AB between two adjacent detection coils 231a and the inner ring of the detection region is the inner - ring intersection point A, and the intersection point of the intersection line AB between two adjacent detection coils 231a and the outer ring of the detection region is the outer - ring intersection point B. The straight line connecting the inner - ring intersection point A and the outer - ring intersection point B on the same intersection line AB does not pass through the center of the inner circle of the annular or semi - annular detection region. Along the preset direction, the projection of the outer - ring intersection point B on the previous intersection line A m-1 B m-1 in the circumferential direction of the inner - circle circumference of the annular or semi - annular detection region is located behind the projection of the inner - ring intersection point A on the subsequent intersection line A m-1 B m in the circumferential direction of the inner - circle circumference of the annular or semi - annular detection region, as shown in m m Figure 6 . Among them, n≥3 and n∈Z, n≥m≥2 and m∈Z.

[0055]

[0056] In some embodiments, the intersection line between two adjacent detection coils is a curve, and the shape of the sub - detection region is crescent - shaped.

[0056] Second Embodiment

[0057] Please refer to Figure 7A 、 7B and 7C, which are schematic structural diagrams of a direction detection antenna provided by the second embodiment of the present utility model. Figure 7A 、 7B and 7C respectively show the layout diagrams of three detection coils on the same substrate. The direction detection antenna 23 includes n mutually insulated detection coils 231b and a substrate 233b. The detection coils 231b are arranged on the surface of the substrate 233b to form an annular detection area. Among three adjacent detection coils 231b, the projection of the middle detection coil 231b in the circumferential direction within the annular detection area is completely covered by the projections of the front and rear detection coils 231b in the circumferential direction within the annular detection area. Specifically, among three adjacent detection coils 231b, the middle detection coil 231b is completely covered by the front and rear detection coils 231b, that is, each part of the detection area is occupied by at least two detection coils 231b simultaneously.

[0058] Thus, when the resonant circuit 26 rotates relative to the detection coil 231b along the circumferential direction of the detection area, the projection of the resonant circuit 26 in the detection area must have an overlapping area with at least two mutually covering detection coils 231b.

[0059] It should be noted that the cases of being in the same layer, the lower layer covering the upper layer, and the upper layer covering the upper layer are all the above-mentioned covering situations. Specifically, the detection coil 231b is formed by winding a wire. For two adjacent detection coils 213b, a gap can be reserved between the wires when one detection coil 213b is wound to arrange the wire of the other detection coil 213b. At this time, the covering parts of the two adjacent detection coils 213b are on the same layer on one side surface of the substrate 233b; insulating glue can be used to space two partially overlapping detection coils 213b. At this time, the covering parts of the two adjacent detection coils 213b are on different layers on one side surface of the substrate 233b; the covering parts of two adjacent detection coils 213b are respectively arranged on two opposite surfaces of the substrate 233b and are on different layers.

[0060] It can be understood that complete coverage includes the cases of adjacent coverage and over-coverage.

[0061] The case of adjacent coverage is specifically described as follows:

[0062] Each of the detection coils 231b includes a first portion 2311b and a second portion 2313b. Along the preset direction, in two adjacent detection coils 231b, the second portion 2313b of the previous detection coil 231b completely overlaps with the first portion 2311b of the subsequent detection coil 231b, as Figure 7A-7C and Figure 8 shown, Figure 8 is a side view schematic diagram of the detection coils of the direction detection antenna provided in the second embodiment of the present invention disposed on the same side surface of the substrate. Among them, Figure 7A-7C the solid line portion of the detection coil 231b in the figure represents the portion located on one side surface of the substrate 233b, and the dashed line portion represents the portion located on the other side surface of the substrate 233b. The second portion 2313b of the previous detection coil 231b and the first portion 2311b of the subsequent detection coil 231b are respectively located on both side surfaces of the substrate 233b, forming a complete overlap; Figure 8 the detection coils 231b in the figure are disposed on the same side surface of the substrate 233b and are insulated and stacked on top of each other to form a complete overlap.

[0063] Preferably, at least three detection coils 231b are correspondingly distributed to form at least three sub-detection regions. The shape of each sub-detection region is the same. The number of detection coils 231b is n. The central angle of two adjacent sub-detection regions relative to the center of the inner circle of the annular detection region is 360° / n, and the central angle of each sub-detection region relative to the center of the inner circle of the annular detection region is 720° / n. For example, when n = 3, among the three sub-detection regions X1X1, X2X2, and X3X3, the central angle of two adjacent sub-detection regions relative to the center of the inner circle of the annular detection region is 120°, and the central angle of each sub-detection region relative to the center of the inner circle of the annular detection region is 240°, as Figure 7A-7C shown; when n = 4, the central angle of two adjacent sub-detection regions relative to the center of the inner circle of the annular detection region is 90°, and the central angle of each sub-detection region relative to the center of the inner circle of the annular detection region is 180°, as Figure 9A-9D shown, Figure 9A-9D respectively showing the setting diagrams of four detection coils on the same substrate.

[0064] The specific description of the over-coverage situation is as follows:

[0065] Please refer to Figure 10, which is a side view schematic diagram of the detection coil of the direction detection antenna provided in the second embodiment of the present invention, disposed on the same side surface of the substrate. Among the adjacent three detection coils 231b, the middle detection coil 231b is completely covered by the front and rear detection coils 231b in cooperation, and the front and rear detection coils 231b partially overlap each other to form a triple coverage area Y.

[0066] In some embodiments, the detection coils are disposed on the same layer or different layers on one side surface of the substrate. Each detection coil includes a first part and a second part. Along the preset direction, among the adjacent two detection coils, the second part of the previous detection coil completely overlaps with the first part of the subsequent detection coil.

[0067] In some embodiments, the detection coils are disposed on the same layer or different layers on one side surface of the substrate. Among the adjacent three detection coils, the middle detection coil is completely covered by the front and rear detection coils in cooperation, and the front and rear detection coils partially overlap each other to form a triple coverage area.

[0068] In some embodiments, the adjacent two detection coils are respectively disposed on the two side surfaces of the substrate. Each detection coil includes a first part and a second part. Along the preset direction, among the adjacent two detection coils, the second part of the previous detection coil completely overlaps with the first part of the subsequent detection coil.

[0069] In some embodiments, the adjacent two detection coils are respectively disposed on the two side surfaces of the substrate. Among the adjacent three detection coils, the middle detection coil is completely covered by the front and rear detection coils in cooperation, and the front and rear detection coils partially overlap each other to form a triple coverage area.

[0070] In some embodiments, each detection coil includes a first part and a second part. The substrate includes a via 2331, opposite front and back surfaces. The via 2331 connects the front surface and the back surface. The first part is located on the front surface, the second part is located on the back surface, and the first part and the second part are connected through the via 2331. Along the preset direction, among the adjacent two detection coils, the first part of the subsequent detection coil completely covers the second part of the previous detection coil.

[0071] Specifically, along the preset direction, among the adjacent two detection coils, the second part of the previous detection coil can completely overlap with the first part of the subsequent detection coil, as Figure 7A-7C shown in FIGS. 9C-9D; or, among the adjacent three detection coils, the middle detection coil is completely covered by the front and rear detection coils in cooperation, and the front and rear detection coils partially overlap each other to form a triple coverage area.

[0072] Third Embodiment

[0073] Please refer to Figure 11 , which is a schematic structural diagram of the direction detection antenna provided by the third embodiment of the present utility model. The direction detection antenna 23 includes n mutually insulated detection coils 231c and a substrate 233c. The detection coils 231c are arranged on one side or both sides of the substrate 233c. The arc length intercepted by the resonant circuit 26c on the preset trajectory is greater than the arc length intercepted by any one of the detection lines 231c on the preset trajectory, so that the projection Z of the resonant circuit 26c in the detection area has an overlapping area with at least two of the detection coils at any rotation position.

[0074] The above are only the embodiments of the present utility model. It should be noted here that for those of ordinary skill in the art, without departing from the creative concept of the present utility model, improvements can still be made, but these all fall within the protection scope of the present utility model.

Claims

1. An electromagnetic encoder, comprising a control circuit, characterized in that: include: A direction detection antenna, electrically connected to the control circuit, comprising at least three mutually insulated detection coils, wherein the at least three detection coils are sequentially distributed along a preset direction to form an annular or semi-annular detection area; The resonant circuit is arranged opposite to the direction detection antenna and is rotatably arranged on a preset trajectory relative to the detection coil along the circumference of the detection area. The projection of the resonant circuit on the detection area is at any rotation position, and the inductive magnetic lines of force of the resonant circuit pass through at least two of the detection coils.

2. The electromagnetic encoder according to claim 1, characterized in that: The projection of the resonant circuit on the detection area has an overlapping area with at least two detection coils at any rotation position.

3. The electromagnetic encoder according to claim 1, characterized in that: Among the three adjacent detection coils, the projection of the middle detection coil in the circumferential direction of the inner circle of the annular or semi-annular detection area is completely covered by the projections of the two front and rear detection coils in the circumferential direction of the inner circle of the annular or semi-annular detection area.

4. The electromagnetic encoder according to claim 1, characterized in that: One end of the boundary line of two adjacent detection coils is located in the inner ring of the detection area, and the other end is located in the outer ring of the detection area. The projections of the two adjacent boundary lines in the circumferential direction of the inner circle of the annular or semi-annular detection area are connected or there is an overlapping area.

5. The electromagnetic encoder according to claim 1, characterized in that: The detection area is annular, and each of the detection coils includes a first part and a second part. Along the preset direction, of two adjacent detection coils, the first part of the latter detection coil completely covers the second part of the former detection coil.

6. The electromagnetic encoder according to claim 5, characterized in that: It also includes a substrate, which includes a via hole, a front side and a back side opposite to each other, the via hole connects the front side and the back side, the first part is located on the front side, the second part is located on the back side, and the first part and the second part are connected through the via hole.

7. The electromagnetic encoder according to claim 1, characterized in that: At least three detection coils are correspondingly distributed to form at least three sub-detection areas, each of the sub-detection areas has the same shape, the number of the detection coils is n, the center angle of two adjacent sub-detection areas relative to the inner circle of the annular or semi-annular detection area is α / n, and the center angle of each sub-detection area relative to the inner circle of the annular or semi-annular detection area is 2α / n, wherein n is an integer greater than or equal to 3, and α is the center angle of the detection area.

8. The electromagnetic encoder according to claim 1, characterized in that: At least three detection coils are distributed correspondingly to form at least three sub-detection areas, and each detection coil is a multi-turn coil wound by a wire, covering one sub-detection area.

9. A direction detection antenna, characterized in that: include: At least three mutually insulated detection coils are sequentially distributed along a preset direction to form an annular or semi-annular detection area. Among the three adjacent detection coils, the projection of the middle detection coil in the circumferential direction of the inner circle of the annular or semi-annular detection area is completely covered by the projections of the two front and rear detection coils in the circumferential direction of the inner circle of the annular or semi-annular detection area.

10. The direction detection antenna according to claim 9, characterized in that: One end of the boundary line of two adjacent detection coils is located in the inner ring of the detection area, and the other end is located in the outer ring of the detection area. The projections of the two adjacent boundary lines in the circumferential direction of the inner circle of the annular or semi-annular detection area are connected or there is an overlapping area.

11. The direction detection antenna according to claim 10, characterized in that: The intersection point of the boundary line with the inner ring of the detection area is the inner ring intersection point, and the intersection point of the boundary line with the outer ring of the detection area is the outer ring intersection point. Along the preset direction, the straight line where the outer ring intersection point of the previous boundary line and the inner ring intersection point on the next boundary line are located passes through the center of the inner circle of the annular or semi-annular detection area.

12. The direction detection antenna according to claim 9, characterized in that: Among the three adjacent detection coils, the detection coil located in the middle is completely covered by the two detection coils in front and behind.

13. The direction detection antenna according to claim 9, characterized in that: The detection area is annular, each of the detection coils includes a first part and a second part, and along the preset direction, of two adjacent detection coils, the second part of the previous detection coil completely overlaps with the first part of the next detection coil.

14. The direction detection antenna according to claim 13, characterized in that: It also includes a substrate, which includes a via hole, a front side and a back side opposite to each other, the via hole connects the front side and the back side, the first part is located on the front side, the second part is located on the back side, and the first part and the second part are connected through the via hole.

15. The direction detection antenna according to claim 9, characterized in that: At least three detection coils are correspondingly distributed to form at least three sub-detection areas, each of the sub-detection areas has the same shape, the number of the detection coils is n, the center angle of two adjacent sub-detection areas relative to the inner circle of the annular or semi-annular detection area is α / n, and the center angle of each sub-detection area relative to the inner circle of the annular or semi-annular detection area is 2α / n, wherein n is an integer greater than or equal to 3, and α is the center angle of the detection area.

16. The direction detection antenna according to claim 9, characterized in that: At least three detection coils are distributed correspondingly to form at least three sub-detection areas, and each detection coil is a multi-turn coil wound by a wire, covering one sub-detection area.

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