Inductive encoder

Abstract

The invention discloses an inductive encoder. The inductance type encoder comprises a stator module and a rotor module. The stator module comprises a circuit board, at least two excitation coil groups and a plurality of induction coil groups; the circuit board comprises a plurality of laying layers and a plurality of wire outlet layers; the excitation coil group comprises at least two excitation coils; the excitation coils are arranged on the arrangement layers, and the excitation coils are arranged in one-to-one correspondence with the arrangement layers and the wire outlet layers. One excitation coil group leads out wires to be connected into each wire outlet layer; at least two induction coil groups form a code channel, and at least one code channel is arranged between the adjacent excitation coil groups; the induction coil group comprises at least two induction coils; a plurality of curve segments of the induction coil are sequentially arranged on the arrangement layers and are connected through via holes, and the induction coil group is led out through the via holes so as to be connected into the wire outlet layers; and the center of the rotor module is symmetrical with the center of the stator module. The technical problem of low precision of the encoder can be solved.

Description

Technical Field

[0001] This application relates to the technical field of encoders, and particularly to an inductive encoder. Background Art

[0002] An inductive encoder is a new type of magnetic encoder, which consists of a stator and a rotor. Among them, the stator includes a circuit board, excitation coils and induction coils arranged thereon, and other encoder circuits. The rotor includes a circuit board and copper or other metal materials with a specific shape arranged thereon. It can also be directly composed of metal materials with a specific shape.

[0003] The working principle of the existing inductive encoder is as follows: After a sine, triangular wave or square wave excitation signal is applied to the excitation coil, a changing magnetic field will be generated. Due to the principle of electromagnetic induction, the induction coil will generate an induced electromotive force signal corresponding to the excitation signal. Copper or other metals in the rotor will induce eddy currents in the magnetic field generated by the excitation coil, generating an electromagnetic field opposite to the direction of the magnetic field of the excitation coil, weakening the original magnetic field below it. According to the characteristics of the shape of the rotor baffle, at different positions, the induced electromotive force and polarity generated by the induction coil are also different. Therefore, the relative angle between the rotor and the induction coil can be calculated, thereby realizing the angle calculation of the encoder.

[0004] To ensure the accuracy of the angle calculation of the inductive encoder, the quality of the original induction signal generated by the induction coil is extremely important. There are many common coil drawing schemes at present. According to different actual application scenarios, there are certain differences in the drawing method of the coil. However, the induced electromotive force generated by the existing coil drawing method is very weak, and the quality of the generated induction signal is poor, seriously affecting the accuracy of the encoder. Summary of the Invention

[0005] The main technical problem to be solved by this application is to provide an inductive encoder that can solve the technical problem of low accuracy of the encoder.

[0006] To solve the above technical problem, a technical solution adopted by this application is: The inductive encoder includes: A stator module, the stator module includes a circuit board, at least two excitation coil groups and a plurality of induction coil groups; The circuit board includes a plurality of layout layers and a plurality of lead-out layers; The excitation coil group includes at least two excitation coils; the excitation coils are arranged on each of the layout layers, and each of the excitation coils is respectively arranged in one-to-one correspondence with the layout layer and the lead-out layer; and one of the excitation coil groups is led out to access each of the lead-out layers; The induction coil groups, with at least two of them forming a code track, and at least one code track being arranged between adjacent excitation coil groups; the induction coil groups include at least two induction coils; multiple curve segments of the induction coils are sequentially arranged on respective laying layers and connected by vias, and the induction coil groups lead out wires through vias to access respective wire-out layers; The rotor module, the center of which is symmetric with the center of the stator module.

[0007] Optionally, for the excitation coil, its starting point is connected to the starting point of the same group of excitation coils on the adjacent laying layer by a via, and its ending point is connected to the ending point of the same group of excitation coils on the adjacent laying layer by a via; and the wires are led out through the vias at the ending points of the outermost excitation coils to access respective wire-out layers.

[0008] Optionally, the excitation coils are connected to adjacent excitation coils on the same laying layer by wires.

[0009] Optionally, the excitation coil is in a spiral shape, and its ending point is connected to the starting point of the adjacent outer excitation coil on the same laying layer by a wire.

[0010] Optionally, the excitation coil is in an equally spaced circular arc shape or a straight line shape, and it is connected to the adjacent outer excitation coil on the same laying layer by multiple parallel straight lines.

[0011] Optionally, the drawing formula of the excitation coil is the following formula (1): M = a + b * θ (1); Wherein, M represents that the excitation coil is in a spiral shape; a is the distance between the starting point of the excitation coil and the polar coordinate center, which can be used as the inner diameter of the excitation coil; b represents the value corresponding to the increase of each unit angle r of the excitation coil, used to control the distance between adjacent excitation coils; θ represents the range and direction of the excitation coil; when θ ∈ [0, 2 * p * π], p represents the number of turns of the excitation coil.

[0012] Optionally, the induction coil is a sine curve, and each curve segment is between extreme value points in the sine curve. Adjacent curve segments are sequentially arranged on respective laying layers, and adjacent curve segments are connected by vias; The induction coils of at least two induction coil groups in the same code track are symmetric based on the same reference circle.

[0013] Optionally, the drawing formula of the induction coil is the following formula (2): R = c + m * sin(n * θ + θx) (2); Wherein, R represents the shape of the induction coil; c represents the radius of the reference circle; m represents the amplitude of the induction coil; n represents the number of pole pairs of the induction coil; θ ∈ [0, 2π]; θx represents the angle of clockwise rotation of the induction coil.

[0014] Optionally, the rotor module includes a baffle unit provided corresponding to each code track one by one; For the baffle unit, the inner diameter of its reference circle is at least smaller than the inner diameters of at least two induction coil groups on the same code track, and the outer diameter of its reference circle is at least larger than the outer diameters of at least two induction coil groups on the same code track; The baffle unit includes a plurality of baffles corresponding to the number of pole pairs of the induction coil; the baffles are in one-to-one correspondence with the number of pole pairs of the induction coil.

[0015] Optionally, for the induction coil group, each induction coil passes through holes at one end and each induction coil passes through holes at the other end to lead out wires, so as to be connected to each wire outlet layer.

[0016] Different from the prior art, the embodiment of the present application provides an inductive encoder, and the inductive encoder includes: a stator module and a rotor module; the stator module includes a circuit board, at least two excitation coil groups and a plurality of induction coil groups; the circuit board includes a plurality of layout layers and a plurality of wire outlet layers; the excitation coil group includes at least two excitation coils; the excitation coils are arranged on each layout layer, and each excitation coil is respectively arranged in one-to-one correspondence with the layout layer and the wire outlet layer; and one of the excitation coil groups leads out wires to be connected to each wire outlet layer; the induction coil group, at least two induction coil groups form a code track, and at least one code track is arranged between adjacent excitation coil groups; the induction coil group includes at least two induction coils; a plurality of curved segments of the induction coil are sequentially arranged on each layout layer and are connected by via holes, and the induction coil group uses via holes to lead out wires to be connected to each wire outlet layer; the rotor module, the center of the rotor module is symmetric with the center of the stator module. It can solve the technical problem of low accuracy of the encoder. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the layout effect of the stator module and the rotor module of the inductive encoder of the present application; Figure 2 It is a schematic diagram of the layout of the double code track type 2 coils of the inductive encoder of the present application; Figure 3 It is a schematic diagram of the configuration of a single excitation coil group of the inductive encoder of the present application; Figure 4 It is a schematic diagram of the layout of the double code track excitation coils and induction coils of the inductive encoder of the present application; Figure 5 It is an effect diagram of the layout of the arc-shaped excitation coils of the inductive encoder of the present application; Figure 6 This is the effect diagram of the linear encoder rotor module of the inductive encoder of the present application; Figure 7 This is a schematic diagram of the configuration of an induction coil group of the inductive encoder of the present application; Figure 8 This is a schematic diagram of the configuration of two induction coil groups of the inductive encoder of the present application; Figure 9 This is a schematic diagram of the layout of the single-track induction coils of the inductive encoder of the present application; Figure 10 This is a schematic diagram of the layer spacing of the inductive encoder of the present application; Figure 11 This is a schematic diagram of the layout of the rotor module of the inductive encoder of the present application; Figure 12 This is a schematic diagram of the copper plating effect of the rotor module of the inductive encoder of the present application.

[0018] Reference numerals: stator module 100; excitation coil 101; induction coil 102; rotor module 200; starting point 1 of the clockwise winding spiral; ending point 2 of the counterclockwise winding spiral; starting point 3 of the counterclockwise winding spiral; ending point 4 of the clockwise winding spiral; one of the vias 5 of the induction coil; layer spacing 6; starting point 7 of the black part and the gray part of the first excitation coil group; ending point 8 of the gray coil part of the first excitation coil group; ending point 9 of the black coil part of the first excitation coil group; starting point 10 of the gray part of the second excitation coil group; starting point 11 of the black coil part of the second excitation coil group; ending point 12 of the black part of the second excitation coil group; ending point 13 of the gray part of the second excitation coil group; starting point 14 of the black part of the third excitation coil group; starting point 15 of the gray part of the third excitation coil group connected; first via 17 of the first track; second via 18 of the first track; third via 19 of the first track; first via 20 of the second track; second via 21 of the second track; third via 22 of the second track; ending point 23 of the black part of the third excitation coil group; ending point 24 of the gray part of the third excitation coil group; connecting line 25 of the first excitation coil on the first layer; connecting line 26 of the first excitation coil on the second layer; first lead 27; second lead 28; excitation coil lead-out 30; excitation coil connection via 31; induction coil lead-out 32; equally spaced inner excitation coils 33; equally spaced outer excitation coils 34; induction coil 35; connection point 36 of the inner and outer excitation coils; mutually parallel straight lines 37; first sine curve 70; second sine curve 71; third sine curve 80; fourth sine curve 81; fifth sine curve 82; sixth sine curve 83; baffle 84. Detailed implementation manners

[0019] The present application will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0020] In this embodiment, it is considered that the original signal quality of the coils of the existing inductive encoder is relatively poor, resulting in a reduction in the accuracy of the encoder. Specifically, the peaks of the original signals obtained by two induction coils in the same code track are different; the sinusoidality of the original signal is poor; and the median points of the original envelope signals obtained by the two coils in the same code track are not the same.

[0021] To solve the above problems existing in the current inductive encoder, the embodiment of the present application provides a method for drawing and arranging the coils of an inductive encoder. By optimizing the drawing method and layout of the coils, the original induced electromotive force signal generated by the induction coils has better sinusoidality and anti-interference ability, and the amplitude difference of the induction signals between the same code tracks is small, thereby improving the accuracy of the inductive encoder.

[0022] Please refer to Figure 1 , Figure 1 which is a schematic diagram of the layout effect of the stator module and the rotor module of the inductive encoder of the present application. As Figure 1 shown, the inductive encoder may include a stator module 100 and a rotor module 200.

[0023] The center of the stator module 100 is symmetrical with the center of the rotor module 200, and through the combined action of the stator module 100 and the rotor module 200, electromagnetic induction can be generated to drive the movement of the device. Among them, the stator module 100 may be composed of a multi-layer circuit board, at least two groups of excitation coils 101, and multiple groups of induction coils 102.

[0024] The multi-layer circuit board may include a layout layer for arranging the excitation coils 101 and the induction coils 102, and an outgoing line layer for accessing the outgoing lines of the groups of excitation coils 101 and the groups of induction coils 102, and then accessing the encoder circuit through the outgoing line layer.

[0025] Each group of excitation coils 101 may include at least two excitation coils 101, and each excitation coil 101 is located on a different layout layer, thereby improving the utilization rate of the board surface of the circuit board and making the magnetic field signal generated by each group of excitation coils 101 stronger. It can be understood that the excitation coils 101 may also be grouped in more numbers. For example, each group of excitation coils 101 may have three or even four excitation coils 101 with the same outer diameter and inner diameter and are arranged on different layers of the circuit board. At the same time, since the number of excitation coils 101 in each group of excitation coils 101 corresponds to the number of layout layers and is set, the number of layout layers of the circuit board also correspondingly increases.

[0026] There are at least two sets of induction coils 102 in each code track, and there is at least one code track between adjacent sets of excitation coils 101. This can ensure that there are excitation coils 101 on both the outermost and innermost sides of the stator module 100, which can more effectively sense the change of the magnetic field signal of the excitation coil 101, making the induced electromotive force generated by the induction coil 102 larger, more stable, and with stronger anti-interference ability. Each set of induction coils 102 includes at least two induction coils 102. The induction coil 102 can be curved. By truncating the induction coil 102 into multiple curved segments, the adjacent curved segments can be arranged on each laying layer in sequence and connected by vias.

[0027] It can be understood that if the actual space of the stator module 100 is relatively small, in order to save wiring space, the number of sets of excitation coils 101 can also be reduced. For example, in an exemplary embodiment, please refer to Figure 2 , Figure 2 which is a schematic diagram of the wiring of the double-code track type 2 coils of the inductive encoder of the present application. Figure 2 It shows the wiring of the double-code track induction coils 102 of two sets of excitation coils 101.

[0028] Multiple sets of excitation coils 101 can be led out through one set of excitation coil 101 leads. For example, they can be led out through the excitation coil 101 leads of the innermost or outermost set of excitation coils 101, and then connected to each outgoing line layer of the circuit board by vias; at the same time, each set of induction coils 102 is intercepted and pulled out through the intersection point at one end of its induction coil 102, and the intercepted other end is connected by a via, and then led out to access each outgoing line layer of the circuit board.

[0029] Among them, the excitation coil 101 is arranged on the front side of the laying layer of the circuit board, the via is arranged on the back side of the laying layer of the circuit board, and the leads of the excitation coil 101 and the induction coil 102 can both be connected by vias from the other side of the multi-layer circuit board. This can reduce the interference to the signal caused by the induced electromotive force generated by capturing the magnetic field in the area surrounded by the leads on the plane perpendicular to the circuit board; and through the outgoing line layer, the leads of the excitation coil 101 and the induction coil 102 are on different layers respectively, so that all the wirings of the excitation coil 101 and the induction coil 102 do not intersect, and the reliability of the coil shape is high, avoiding the problem of poor signal quality caused by the abnormal shape of the coil.

[0030] It should be noted that each excitation coil 101 can be drawn by a single copper wire, avoiding the problem of current discontinuity that may be caused by the connection of multiple wires, making the generated magnetic field more consistent and smooth. And a certain distance can be set between each group of excitation coils 101. The specific wiring is related to the induction coil 102. For example, the distance between the two parts of the induction coil 102 is very small, and the distance from the rotor module 100 is closer, and the captured magnetic field is stronger and more uniform, effectively reducing the deterioration of the sinusoidality and the amplitude difference of the induction signal caused by the tilt of the rotor module 200. For example, for the excitation coil 101 in the middle of multiple induction coil 102 tracks, the distances from the two induction coil 102 tracks should be approximately the same.

[0031] Furthermore, the excitation coils 101 of the same group of excitation coils 101 are correspondingly arranged on different laying layers. The starting point of the excitation coil 101 on each laying layer and the starting point of the excitation coil 101 of the same group on the adjacent laying layer are connected by corresponding vias; the end point of the excitation coil 101 and the end point of the excitation coil 101 of the same group on the adjacent laying layer are connected by corresponding vias, so that the winding directions of the excitation coil 101 and the excitation coil 101 of the same group on the adjacent laying layer are opposite. Among them, the via connecting lines between the excitation coils 101 are located on the side of the circuit board opposite to the induction coil 102, thus avoiding the problem of crossing between the excitation coils 101 when they are connected.

[0032] Then, these groups of excitation coils 101 can be led out through the via lead-out lines at the end points of the excitation coils 101 of the outermost excitation coil group on each laying layer to access the lead-out layer, so that the excitation coils 101 of each laying layer can be respectively connected to the circuit through the lead-out layer.

[0033] Furthermore, the excitation coil 101 can be one of a spiral shape, an arc shape, and a straight shape.

[0034] In an exemplary embodiment, the excitation coil 101 can be in a spiral shape; please refer to Figure 3 , Figure 3 , which is a schematic diagram of the configuration of a single excitation coil group of the inductive encoder of the present application. Taking the three-turn spiral excitation coil 101 as an example, Figure 3 shows the starting point 1 of the clockwise winding spiral line, the ending point 2 of the counterclockwise winding spiral line, the starting point 3 of the counterclockwise winding spiral line, and the ending point 4 of the clockwise winding spiral line. A stronger alternating magnetic field can be generated through two superimposed excitation coils 101, making the generated induced electromotive force have a larger amplitude and be more stable.

[0035] Specifically, the end points of the excitation coils 101 can be connected to the start points of the excitation coils 101 in different adjacent outer groups on the same layout layer by wires, so that the winding directions of the excitation coils 101 in different adjacent groups on the same layout layer are the same. The end points and start points of the adjacent different groups of excitation coils 101 are connected to the end points and start points of the adjacent outer excitation coils 101 by vias, and the connecting wires are arranged on the wire outlet layer of a different board layer from the induction coils 102 and the excitation coils 101.

[0036] Among them, multiple groups of excitation coils 101 can be arranged on the circuit board, and the quantity can be determined by the size of the circuit board and the quantity of the induction coils 102. The optimal quantity of the excitation coils 101 can be determined by the quantity of the induction coils 102. When there are induction coils 102 with S barcode tracks, the optimal quantity of the groups of excitation coils 101 is S + 1 groups. To ensure that excitation coils 101 are arranged both inside and outside the barcode tracks of the induction coils 102.

[0037] Therefore, taking the double-barcode-track induction coils 102 and three groups of excitation coils 101 as an example, each group of excitation coils 101 includes two excitation coils 101 to explain the connection of multiple groups of excitation coils 101. Correspondingly, a four-layer circuit board is set up. Among them, this four-layer circuit board includes a first layout layer and a second layout layer for respectively arranging two excitation coils 101, and a wire outlet layer for the wire outlet of the groups of excitation coils 101 and the groups of induction coils 102.

[0038] In an exemplary embodiment, please refer to Figure 4 , Figure 4 which is a schematic diagram of the layout of the double-barcode excitation coils and induction coils of the inductive encoder of the present application. The black coil parts can be arranged on the first layout layer, and the gray coil parts can be arranged on the second layout layer. The black coil part and the gray coil part of the first group of excitation coils 101 can be connected through a via at the starting point position of the punching 7 of the first group of excitation coils 101. The end point 9 of the black coil part of the first group of excitation coils 101 is connected to the starting point 11 of the black coil part of the second group of excitation coils 101, and the end point 8 of the gray coil part of the first group of excitation coils 101 is connected to the starting point 10 of the gray part of the second group of excitation coils 101. And the connecting wires between each group of coils are located on the side of the four-layer circuit board opposite to the induction coils 102, so that there will be no intersection between the excitation coils 101 when they are connected. Similarly, the end point 12 of the black part of the second group of excitation coils 101 is connected to the starting point 14 of the black part of the third group of excitation coils 101, and the end point 13 of the gray part of the second group of excitation coils 101 is connected to the starting point 15 of the gray part of the third group of excitation coils 101. Finally, two wires are led out from the end point 23 of the black part of the third group of excitation coils 101 and the end point 24 of the gray part of the third group of excitation coils 101 and connected to the wire outlet layer of the circuit board.

[0039] In an exemplary embodiment, the excitation coil 101 can be in the form of equally spaced circular arcs. Among them, the circular arc inductive encoder excitation coil 101 can be drawn using equally spaced arcs, and adjacent two groups of excitation coils 101 can be connected by parallel straight lines.

[0040] Please refer to Figure 5 , Figure 5 which is the layout effect diagram of the circular arc excitation coil of the inductive encoder of the present application. As shown in the figure, the excitation coil lead 30; the excitation coil connection via hole 31; the induction coil lead 32; the equally spaced inner excitation coils 33; the equally spaced outer excitation coils 34; the induction coil 35; the connection part 36 of the inner and outer excitation coils; the parallel straight lines 37. It can be seen that the excitation coils 101 on the same layout layer surround from the outer excitation coil 101 to the inner excitation coil 101 in a "hui" shape, which can ensure that the current on the same layout layer flows in opposite directions on the inner and outer arcs. The ends of the excitation coils 101 on different layout layers are connected by vias. In general, the circular arc excitation coil 101 is suitable for single track or double track, and generally two groups of excitation coils 101 can be used.

[0041] For the equally spaced circular arc excitation coil 101, the induction coil 102 is generated in the same way. Please continue to refer to Figure 5 When obtaining the induction coil 102, a part can be intercepted from the generated complete circle according to requirements, and then the tails of each group of induction coils 102 are connected by vias and then placed between the two groups of excitation coils 101. The layout and lead methods of the induction coils 102 are the same, and the generation and layout of the rotor module 200 are the same.

[0042] In an exemplary embodiment, the excitation coil 101 can be in the form of equally spaced straight lines. Among them, the straight line inductive encoder excitation coil 101 is changed from the equally spaced circular arc excitation coil 101 to equally spaced parallel straight lines, and the connection and layout methods are the same. The induction coil 102 is obtained by using the above generation equation of the induction coil 102 in the rectangular coordinate system to generate multiple induction coils 102 with a certain phase difference, and then intercepted according to needs. The layout method of the induction coil 102 is also the same. Please refer to Figure 6 , Figure 6 which is the layout effect diagram of the straight line encoder rotor module of the inductive encoder of the present application. The copper-clad area of the rotor module 200 changes from a sector to a rectangle, and the layout method changes from a circle to a straight line.

[0043] Furthermore, the drawing formula of the excitation coil 101 is as follows formula (1): M = a + b * θ (1); Among them, M indicates that the excitation coil 101 is spiral; a is the distance between the starting point of the excitation coil 101 and the polar coordinate center, which can be used as the inner diameter of the excitation coil 101; b represents the value corresponding to each unit increase in the angle r of the excitation coil 101, and is used to control the distance between adjacent excitation coils 101; θ represents the range and direction of the excitation coil 101; when θ ∈ [0, 2*p*π], p represents the number of turns of the excitation coil 101.

[0044] Among them, the corresponding values of a, b, and θ can be determined according to the actual requirements of the inner diameter and outer diameter of the encoder, so as to design an excitation coil 101 with a suitable size. In an exemplary embodiment, please continue to refer to Figure 3 , such as Figure 3 shown. Taking the three-turn spiral excitation coil 101 as an example, for the forward coil, a is 15, b is 0.1, θ ∈ [0, 6π], and a spiral line that winds counterclockwise for three turns is drawn. For the reverse coil, θ ∈ [-6π, 0], a is 15, b is -0.1, and a spiral line that winds clockwise for three turns is drawn. The two spiral coils form a group of single-track excitation coils 101.

[0045] Furthermore, the drawing formula of the induction coil 102 is the following formula (2): R = c + m * sin(n * θ + θ x ) (2); Among them, R represents the shape of the induction coil 102; c represents the radius of the reference circle; m represents the amplitude of the induction coil 102; n represents the number of pole pairs of the induction coil 102; θ ∈ [0, 2π]; θ x represents the angle of clockwise rotation of the induction coil 102.

[0046] Each group of induction coils 102 is composed of two sine curves. The phase difference between the two curves is π. In an exemplary embodiment, please refer to Figure 7 , Figure 7 which is a schematic diagram of the configuration of a group of induction coils of the inductive encoder of the present application. The figure shows that a group of induction coils 102 includes a first sine curve 70 and a second sine curve 71. Generally, at least two groups of induction coils 102 are required for one track. Of course, it can also be three groups of induction coils 102, four groups of induction coils 102 or more. Among them, three groups of induction coils 102 correspond to a three-phase encoder, and four groups of induction coils 102 correspond to a four-phase encoder.

[0047] Furthermore, if the actual requirement is an inductive encoder coil with h phases, x phase difference, and y pairs of poles. Then, 2*h sine curves included in h groups of induction coils 102 need to be generated according to the above sine curve equation. The phase difference Δθ x between adjacent two groups of induction coils 102 is x.

[0048] In an exemplary embodiment, please refer to Figure 8 , Figure 8 which is a schematic diagram of the configurations of two induction coil groups of the inductive encoder of the present application. Taking the single-track, six-pole, two-phase 90° phase difference induction coil 102 as an example, assuming θ x = 0°, c = 10, m = 1, n = 6 and θ x = 180°, c = 10, m = 1, n = 6 to obtain the first induction coil 102 group, including the third sine curve 80 and the fourth sine curve 81; θ x = 90°, c = 10, m = 1, n = 6 and = θ x 270°, c = 10, m = 1, n = 6 to obtain the second induction coil 102 group, including the fifth sine curve 82 and the sixth sine curve 83.

[0049] Furthermore, the induction coil 102 is based on a circle. The induction coils 102 of at least two induction coil 102 groups in the same track are symmetric based on the same reference circle, and the induction coil 102 is a sinusoidal curve that is closed at the head and tail.

[0050] To avoid the problem that the induction coils 102 may intersect in the same laying layer, in the embodiment of the present application, since each radius of the sinusoidal curve has extreme points, that is, maximum and minimum values, when drawing the induction coil 102, the positions of the maximum and minimum values of each radius of the induction coil 102 can be truncated and punched to form the curve segments between the extreme points in the sinusoidal curve, and the adjacent curve segments are sequentially laid on each laying layer, and the adjacent curve segments are connected by vias.

[0051] In an exemplary embodiment, please refer to Figure 9 , Figure 9 which is a schematic diagram of the single-track induction coil layout of the inductive encoder of the present application. One via 5 of the induction coil 102 is a break point between two adjacent parts, so that the two parts of the induction coil 102 located in different layers are connected. Break points are made at the maximum and minimum points of each radius of the induction coil 102 to connect the coils of the upper and lower layers, so that the two induction coil 102 groups on the circuit board will not intersect. In addition, please refer to Figure 10 , Figure 10 which is a schematic diagram of the board layer spacing of the inductive encoder of the present application. As Figure 10 shown, the board layer spacing 6 between the board layer where the black part of the excitation coil 101 is located and the board layer where the gray part of the excitation coil 101 is located cannot be too large and can be on the same side of the circuit board. That is to say, the board layer spacing 6 between each laying layer can be separated by the thickness of an insulating film of the circuit board.

[0052] To solve the problems that the connecting wires of the excitation coils 101 in the inner and outer code tracks of the multi-code track coil intersect with the induction coils 102 in the outer code track and the leads of the induction coils 102 in the inner code track intersect with the excitation coils 101 in the outer code track, the embodiment of the present application is based on the layout method of the excitation coils 101 and the induction coils 102, and an example is given to illustrate the overall layout method of the excitation coils 101 and the induction coils 102 in the stator module 100. In an exemplary embodiment, please continue to refer to Figure 4 , it is assumed that the stator module 100 includes three groups of excitation coils 101, and each group of excitation coils 101 includes two excitation coils 101; and, two code tracks, each code track corresponds to two groups of induction coils 102, and each group of induction coils 102 includes two induction coils 102; wherein, the leads in each group of excitation coils 101 and the induction coils 102 need to be connected by vias from the other side of the four-layer circuit board. Therefore, the coils of the stator module 100 are correspondingly arranged on at least four-layer circuit boards, so that the outgoing wires of the excitation coils 101 are on different outgoing wire layers, and at the same time, the outgoing wires of the induction coils 102 are also on different outgoing wire layers to reduce magnetic field interference.

[0053] Specifically, it is assumed that the excitation coils 101 and the induction coils 102 are placed on the first and second layers of the circuit board. The connecting wire 25 of the first excitation coil 101 on the first layer is connected to the second group of excitation coils 101 by using the via at the end point 12 of the black part of the second group of excitation coils 101, and is connected to the third group of excitation coils 101 by using the via at the starting point 14 of the black part of the third group of excitation coils 101, and the connecting wire 25 of the first excitation coil 101 on the first layer is located on the third layer of the circuit board. The connecting wire 26 of the first excitation coil 101 on the second layer is connected to the second group of excitation coils 101 by using the via at the end point 13 of the gray part of the second group of excitation coils 101, and is connected to the third group of excitation coils 101 by using the via at the starting point 15 of the gray part of the third group of excitation coils 101, and is located on the fourth layer of the circuit board. Thus, it is possible to avoid the intersection of the connecting wire 25 of the first excitation coil 101 on the first layer and the connecting wire 26 of the first excitation coil 101 on the second layer with the induction coils 102 in the outer code track. The first lead 27 and the second lead 28 of the induction coil 102 are also placed on the third and fourth layers respectively. Thus, it is possible to avoid the intersection of the first lead 27 and the second lead 28 of the induction coil 102 with the third group of excitation coils 101. In addition, the area enclosed by the intersection of the first connecting wire 25 and the second connecting wire 26 of the excitation coil 101 and the first lead 27 and the second lead 28 of the induction coil on the Figure 4 plane shown is as small as possible, thereby reducing the interference caused by magnetic field non-uniformity.

[0054] Further, the 102 groups of induction coils lead out wires through the through holes of the induction coils 102 at one end and the through holes of the induction coils 102 at the other end to access each lead-out layer. In an exemplary embodiment, please continue to refer to Figure 4 , one end of the induction coil 102 corresponding to the first code track is connected through the first through hole 17 of the first code track, and the other end leads out wires from different laying layers through the second through hole 18 and the third through hole 19 of the first code track and then accesses the circuit; similarly, one end of the induction coil 102 corresponding to the second code track is connected through the first through hole 20 of the second code track, and the other end leads out wires from different laying layers through the second through hole 21 and the third through hole 22 of the second code track and then accesses the circuit.

[0055] Further, the rotor module 200 may include a baffle unit provided corresponding to each code track one by one. Each baffle unit generates two reference circle radii according to the corresponding code track, namely the inner diameter of the reference circle and the outer diameter of the reference circle; wherein, the inner diameter of the reference circle may be smaller than the inner diameters of the induction coil 102 and the excitation coil 101 of the same code track, and the outer diameter of the reference circle may be larger than the inner diameters of the induction coil 102 and the excitation coil 101 of the same code track, which can ensure that the baffle unit can completely cover the area of the induction coil 102.

[0056] After determining the reference circle, if coils with l pairs of poles are required, the circular ring area enclosed by the inner diameter and the outer diameter of the reference circle can be equally divided into 2*l regions. Finally, 2*l regions are obtained, and copper is plated in every other region among the 2*l regions to obtain the required baffle. The multiple regions obtained by equally dividing the circular ring area can be fan-shaped, horseshoe-shaped, or quasi-sinusoidal.

[0057] For the double code track, 2*l regions of the second code track are generated in the same way on the basis of the single code track, and there should be no connection between adjacent regions and the spacing is very small. It can be understood that the drawing and laying methods of the rotor module 200 with three or more code tracks are also the same.

[0058] In an exemplary embodiment, please refer to Figure 11 , Figure 11 is a schematic layout diagram of the rotor module of the inductive encoder of the present application, Figure 11 showing the corresponding multiple regions of the double code track encoder with 14 pairs of poles for the inner code track and 16 pairs of poles for the outer code track, that is, 2*14 regions for the inner code track and 2*16 regions for the outer code track. Please refer to Figure 12 , Figure 12 is a schematic diagram of the copper plating effect of the rotor module of the inductive encoder of the present application. Copper is plated in every other fan-shaped region in each code track-shaped region, resulting in 14 regions with copper plating in the inner code track, that is, obtaining 14 baffles 84 and 14 blank regions; 16 regions with copper plating in the outer code track, that is, obtaining 16 baffles 84 and 16 blank regions.

[0059] Among them, regarding the overall layout between the retaining piece 84 of the rotor module 200 and the coil in the stator module 100, the retaining piece 84 and the coil should be concentric; the distances between the two parts of the induction coil 102 in the stator module 100 and the retaining piece 84 should be as the same as possible and not too far apart. This can ensure that the retaining piece 84 can completely cover the area of the induction coil 102; and the generated retaining piece 84 should be able to completely cover the excitation coil 101 and the induction coil 102 in the radial direction. The finally obtained induced electromotive force has a small amplitude difference, an even smaller median difference, and a smaller background noise, effectively improving the accuracy of the inductive encoder.

[0060] In several implementation manners provided by the present application, it should be understood that the disclosed methods, electronic devices, and storage media can be implemented in other ways. For example, the device implementation manners described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections with each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0061] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this implementation manner.

[0062] In addition, in each functional unit in various implementation manners of the present application, it can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0063] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the inductive encoder described in various embodiments of this application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0064] The above are only the embodiments of this application, and do not limit the patent scope of this application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of this application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of this application.

Claims

1. An inductive encoder, characterized in that: The inductive encoder comprises: A stator module, the stator module comprising a circuit board, at least two excitation coil groups and a plurality of induction coil groups; The circuit board includes a plurality of layout layers and a plurality of lead-out layers; The excitation coil group includes at least two excitation coils; the excitation coils are arranged on each of the layout layers, and each of the excitation coils is arranged in one-to-one correspondence with the layout layer and the output line layer; and the output line is connected to each of the output line layers through one of the excitation coil groups; The induction coil group, at least two of the induction coil groups form a code channel, and at least one code channel is arranged between adjacent excitation coil groups; the induction coil group includes at least two induction coils; a plurality of curved segments of the induction coils are sequentially arranged on each of the arrangement layers and connected by vias, and the induction coil group uses vias to lead out wires to access each of the lead-out layers; The rotor module has a center that is symmetrical to the center of the stator module.

2. The inductive encoder according to claim 1, characterized in that: The starting point of the excitation coil is connected to the starting point of the excitation coil of the same group on the adjacent layout layer through a via, and the end point of the excitation coil of the same group on the adjacent layout layer through a via; and the wires are connected to each of the output wire layers through the vias at the end points of the excitation coils in the outermost circle.

3. The inductive encoder according to claim 1, characterized in that: The excitation coil is connected to the adjacent excitation coil on the same wiring layer by a wire.

4. The inductive encoder according to claim 3, characterized in that: The excitation coil is in a spiral shape, and an end point of the excitation coil is connected to a start point of the adjacent outer excitation coil on the same layout layer by a wire.

5. The inductive encoder according to claim 3, characterized in that: The excitation coils are in the shape of arcs or straight lines with equal spacing, and are connected to the adjacent outer excitation coils on the same layout layer by using a plurality of straight lines parallel to each other.

6. The inductive encoder according to claim 3, characterized in that: The drawing formula of the excitation coil is as follows (1): M = a + b * θ (1); Among them, M indicates that the excitation coil is spiral; a is the distance between the starting point of the excitation coil and the center of the polar coordinate, which can be used as the inner diameter of the excitation coil; b indicates the increase in the value corresponding to each increase in unit angle r of the excitation coil, which is used to control the distance between adjacent excitation coils; θ indicates the range and direction of the excitation coil; when θ∈[0,2*p*π], p indicates the number of turns of the excitation coil.

7. The inductive encoder according to claim 1, characterized in that: The induction coil is a sine curve, each extreme point in the sine curve is a curve segment, adjacent curve segments are sequentially arranged on each arrangement layer, and adjacent curve segments are connected by vias; The induction coils of at least two induction coil groups of the same code channel are symmetrical based on the same reference circle.

8. The inductive encoder according to claim 7, characterized in that: The drawing formula of the induction coil is as follows (2): R=c+m*sin(n*θ+θ x )(2); Wherein, R represents the shape of the induction coil; c represents the radius of the reference circle; m represents the amplitude of the induction coil; n represents the number of pole pairs of the induction coil; θ∈[0, 2π]; θ x represents the angle of the induction coil rotating clockwise.

9. The inductive encoder according to claim 8, characterized in that: The rotor module includes baffle units arranged in one-to-one correspondence with the code channels; The baffle unit has a reference circle inner diameter at least smaller than the inner diameters of at least two induction coil groups of the same code channel, and a reference circle outer diameter at least larger than the outer diameters of at least two induction coil groups of the same code channel; The baffle unit includes a plurality of baffles corresponding to the number of pole pairs of the induction coil; the baffles correspond to the number of pole pairs of the induction coil one by one.

10. The inductive encoder according to claim 1, characterized in that: The induction coil group is connected to each of the lead-out layers through each of the induction coil via holes at one end and each of the induction coil via holes at the other end.

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