Inductive encoder induction assembly
By employing concentric parallel coil plates and rotor code disks in an inductive encoder, combined with 180° symmetrical compensation, the problem of rotor copper foil arrangement affecting stator magnetic field distribution in traditional electromagnetic induction encoders is solved, achieving higher measurement accuracy and signal stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2026-03-27
AI Technical Summary
The arrangement of rotor copper foil in traditional electromagnetic induction encoders affects the distribution of the stator magnetic field, resulting in reduced position measurement accuracy. Furthermore, the via connection disrupts the radial symmetry of the magnetic field, affecting measurement accuracy and stability.
The coil board and rotor code disk are arranged concentrically and parallelly. The excitation coil and the induction coil are connected in series through PCB leads and layer replacement holes, and 180° symmetrical compensation is set at key positions. The copper foil array on the rotor code disk is set to correspond to the induction coil to ensure stable signal output.
It suppresses additional harmonics, improves measurement accuracy and system dynamic performance, enhances anti-interference capability, and improves signal stability and system stability.
Smart Images
Figure CN224051343U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of split type encoder installation, especially an inductive encoder sensing assembly. BACKGROUND
[0002] The electromagnetic induction type encoder has the characteristics of resisting oil dirt, dust, moisture resistance, easy manufacturing and the like, and is more and more applied to the measurement of rotary or linear motion positions. A common absolute value inductive rotary position sensor is composed of a stator component and a rotor component, the stator component is composed of a PCB on which three groups of excitation coils and two groups of inductive coils with prime number of pole pairs are printed, and is represented as a main code channel M and a vernier code channel N (M>N, and prime to each other), the main code channel M is located between excitation coil 1 and excitation coil 2 arranged radially from outside to inside, and the vernier code channel is located between excitation coil 2 and excitation coil 3. The rotor is composed of a PCB on which corresponding copper foil arrays are printed. There are M and N copper foil arrays.
[0003] In order to ensure the radial offset tolerance of the rotor, the M code channel copper foil array and the N code channel copper foil array of the rotor of the conventional electromagnetic induction type encoder are all pressed to the area where the excitation coil is located. This causes the N code channel to be too close to the stator main code channel inductive coil M, affects the magnetic field distribution of the M code channel inductive coil on the stator, and causes additional harmonic components.
[0004] Since the inductive coils on the stator assembly need to be led out to the calculation board, they are usually located on different layers of the PCB, so they need to be led out through vias. At the same time, the three groups of excitation coils 1, 2 and 3 are connected together through leads, the inductive coils and the excitation coils are located on the same layer, and the leads also need to be connected together through additional vias. These additional metal vias destroy the radial symmetry of the magnetic field distribution of the M code channel inductive coil on the stator, so that the influence of the rotor eccentricity on the position measurement accuracy becomes larger. SUMMARY
[0005] In view of the above problems, the utility model provides an inductive encoder sensing assembly for solving the problems of the prior art.
[0006] The utility model provides a kind of inductive encoder induction subassembly, including concentric parallel opposite arrangement coil board and rotor code disc, the coil board includes: coil substrate, the coil substrate is annular PCB multilayer board;Excitation coil includes first excitation coil, second excitation coil, the excitation coil is concentrically drawn on the coil substrate with different diameters and is connected in series by PCB lead and layer-changing hole, and it is compensated at the series connection place with the center of coil substrate as the center of 180 symmetry position;Induction coil includes M induction coil and N induction coil, wherein, the M induction coil is between the first excitation coil and second excitation coil, the N induction coil is inside the second excitation coil, and the M induction coil and N induction coil are all led out induction signal by PCB lead and layer-changing hole, and it is compensated at the induction signal place with the center of coil substrate as the center of 180 symmetry position;The rotor code disc includes: code disc substrate, the code disc substrate is annular PCB board;M code channel copper foil array is arranged on the code disc substrate, and is uniformly spaced in circumferential direction by first metal copper foil and insulating medium, and is opposite to the M induction coil;N code channel copper foil array is arranged on the code disc substrate, and is uniformly spaced in circumferential direction by second metal copper foil and insulating medium, and is opposite to the N induction coil.
[0007] Preferably, the excitation coil further includes a third excitation coil, the third excitation coil is arranged inside the N induction coil, and is connected in series with the second excitation coil by PCB lead and layer-changing hole, and is compensated at the series connection place with the center of coil substrate as the center of 180 symmetry position.
[0008] Preferably, the annular PCB board is a 4-layer board, a 6-layer board or an 8-layer board. Preferably, the compensation setting is a compensation via hole or a supplementary solder pad.
[0009] Preferably, the height of the first metal copper foil is greater than or equal to the distance from the first excitation coil to the second excitation coil.
[0010] Preferably, the distance between the N induction coil and the second excitation coil is greater than 0.7mm. Preferably, the number of periods of the M induction coil and the N induction coil are different and relatively prime, wherein the number of periods of the M induction coil is greater than the number of periods of the N induction coil.
[0011] Preferably, the M induction coil and the N induction coil each include four sinusoidal curves under polar coordinates, the sinusoidal curves take 0° phase as a reference, with phase differences of 90°, 180° and 270°, the 0° and 180° curves generate SIN induction coil signals, and the 90° and 270° curves generate COS induction coil signals.
[0012] Preferably, the sinusoidal curves are symmetrically and alternately distributed on the adjacent layers of the PCB, and the sinusoidal curves of different layers are connected together through the layer-changing holes at the wave crests and wave troughs.
[0013] Preferably, the M-channel copper foil array and the N-channel copper foil array respectively comprise different numbers of periods and are co-prime, and the number of copper foils of the M-channel copper foil array is greater than the number of copper foils of the N-channel copper foil array.
[0014] Compared with the prior art, the inductive encoder sensing assembly provided by the utility model can inhibit the inductive encoder from generating additional harmonics, ensure stable signal output, improve measurement accuracy, enhance system dynamic performance and stability, and improve anti-interference capability. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a schematic diagram of a coil plate of an inductive encoder sensing assembly.
[0016] Figure 2 It is a partially enlarged schematic diagram of a coil plate of an inductive encoder sensing assembly.
[0017] Figure 3 It is a partially enlarged schematic diagram of a coil plate of an inductive encoder sensing assembly.
[0018] Figure 4 It is a partially enlarged schematic diagram of a coil plate of an inductive encoder sensing assembly.
[0019] Figure 5 It is a partially enlarged schematic diagram of a coil plate of an inductive encoder sensing assembly.
[0020] Figure 6 It is a schematic diagram of a code disc of an inductive encoder sensing assembly.
[0021] Figure 7 It is a schematic diagram of an inductive encoder sensing assembly.
[0022] Figure 8 It is a schematic diagram of another embodiment of an inductive encoder sensing assembly. DETAILED DESCRIPTION
[0023] The utility model will be further described in detail below in combination with the drawings.
[0024] One embodiment of the utility model discloses an inductive encoder sensing assembly, and specifically refers to Figures 1-5 Among them Figures 2-5 It is Figure 1 The local amplification.
[0025] The coil plate 1 adopts a 4-layer circular ring PCB multilayer plate as a coil plate substrate 10, wherein the third layer and the fourth layer of the coil plate substrate 10 are drawn with the excitation coil 11 and the induction coil 12.
[0026] The excitation coil 11 includes a first excitation coil 111, a second excitation coil 112 and a third excitation coil 113 arranged radially and concentrically from outside to inside on the coil plate substrate 10. Each group of excitation coils is wound with three turns of annular coils on the third layer and the fourth layer, the winding directions of the adjacent two groups of excitation coils 11 are opposite, and the annular induction space is formed between the two groups of excitation coils; the fourth layer excitation coil is drawn on the upper and lower of the third layer excitation coil orthographic projection; the three turns of annular coils of each group of excitation coils on the third layer and the fourth layer are connected together through the vias A1 at the tail of the completed drawing; the PCB wiring connection between the first excitation coil 111 and the second excitation coil 112 on the third layer and the fourth layer is connected in series through the layer changing holes B1, B2 and the layer changing holes C1, C2 respectively changing layers to the first layer and the second layer, and then through the PCB wiring connection. The PCB wiring connection between the second excitation coil 112 and the third excitation coil 113 on the third layer and the fourth layer is connected in series through the layer changing holes D1, D2 and the layer changing holes E1, E2 respectively changing layers to the first layer and the second layer. The PCB wiring of the third excitation coil 113 on the third layer and the fourth layer is changed to the first layer and the second layer through the layer changing holes F1 and F2, and is led out to the coil plate 1 lead pad on the first layer.
[0027] M code channel 121 is arranged on the induction space formed by the first excitation coil 111 and the second excitation coil 112, and N code channel 122 is arranged on the induction space formed by the second excitation coil 112 and the third excitation coil 113. Each code channel is composed of four sinusoidal curves in polar coordinates, showing sinusoidal periodicity. The number of periods of the M code channel 121 is greater than that of the N code channel 122, and the number of periods of the two code channels is co-prime. The positions of the four sinusoidal curves in polar coordinates are based on the 0° phase as the reference, with phase differences of 90°, 180° and 270°. The 0° and 180° curve combination SIN induction coil is used to generate the SIN induction coil signal, and the 180° and 270° combination generates the COS induction coil to generate the COS induction coil signal. Each sinusoidal curve is alternately arranged on the third layer and the fourth layer of the coil plate substrate 10. Each half period changes once every two layers, and each half period of each sinusoidal curve is located in the fourth layer, and the other half period is located in the third layer. The front half period overlaps at both ends of the orthogonal projection of the third layer and the other half period. In order to make the front half period and the other half period communicate, layer changing holes are arranged in the overlapping area. However, in order to lead out the signal of the M code channel 121 for processing, the SIN induction coil selects an overlapping area without placing a layer changing hole, but continues to overlap in the direction of the adjacent excitation coil 11, and after a small distance, it is pulled apart in the circumferential direction and placed layer changing holes H1 and H2 to change layers to the first layer of the coil plate substrate 10, and led out to the coil plate lead-out pad located on the first layer. The COS induction coil places layer changing holes H3 and H4 in the same way to change layers to the first layer of the coil plate substrate 10, and leads out to the coil plate lead-out pad located on the first layer. When reaching the lead-out pad, layer changing holes H5, H6, H7 and H8 are also placed to uniformly change the leads to the pads on the first layer.
[0028] In the same way, the SIN induction coil on the N code channel 122 changes layers to the first layer of the coil plate substrate 10 through layer changing holes K1 and K2, and leads out to the coil plate lead-out pad located on the first layer. The COS induction coil on the N code channel 122 changes layers to the first layer through layer changing holes K3 and K4, and leads out to the coil plate lead-out pad located on the first layer. When reaching the lead-out pad, layer changing holes K5, K6, K7 and K8 are also placed to uniformly change the leads to the pads on the first layer.
[0029] For the additional layer-change holes A1, B1, B2, C1, C2, D1, D2, E1, E2, F1, F2, H1, H2, H3, H4, K1, K2, K3, K4, and H5, H6, H7, H8, K5, K6, K7, K8 required for routing, compensation vias should be placed at 180° symmetrical locations with the center of the coil board substrate 10 as the center, or metal pads should be placed at 180° symmetrical locations with the center of the coil board substrate 10 on the third and fourth layers. The diameter of the pads should be the same as the diameter of the pads of each layer-change hole, namely: a1, b1, c2, c1, c2, d1, d2, e1, e2, f1, f2, h1, h2, h3, h4, k1, k2, k3, k4, and h5, h6, h7, h8, k5, k6, k7, k8.
[0030] See Figure 6 , Figure 7 ,in Figure 6 This is a schematic diagram of encoder 2. Figure 7 This is a schematic diagram of the excitation coil 11 and the induction coil 12 projected onto the coil plate 1 by the M-track copper foil array 21 and the N-track copper foil array 22 on the code disk 2.
[0031] The peaks and troughs of the N-track induction coil 122 on the coil plate 1 are 0.8 mm away from the second excitation winding 112 and the third excitation 113, respectively. The layer-changing hole of the M-track induction coil 121 is 0.5 mm away from the first excitation coil 111 and the second excitation coil 112. The corresponding code disk 2 has an M-track copper foil array 21 and an N-track copper foil array 22 on its code disk substrate 20. The copper foil arrays are arranged in a ring, with fan-shaped metal copper foil and insulating medium spaced apart. The M-track copper foil array 21 and the N-track copper foil array 22 correspond one-to-one with the M-track 121 and the N-track 122 on the coil plate. In the operation of the inductive encoder, the rotor and stator need to be placed concentrically. The orthogonal projection of the M-track copper foil array 21 on the code disk 2 onto the coil plate 1 covers the M-track induction coil 121, and the arc edges of the fan-shaped copper foil overlap the first excitation coil 111 and the second excitation coil 112, respectively. The orthographic projection of the N-channel copper foil array 122 on the coil plate 1 covers the N-channel induction coil 122 but does not overlap with the second excitation coil 112 and the third excitation coil 113, but maintains a gap of 0.1 mm.
[0032] Figure 8The utility model discloses an inductive encoder induction subassembly another embodiment, and N code way induction coil 122 sets position is close to second excitation winding coil 112 and third excitation 113, and the distance of N code way induction coil 122 wave crest distance second excitation coil 112 is 1.2mm, and the distance of N code way induction coil 122 wave crest wave trough distance third excitation coil 113 is 0.5mm.M code way induction coil 121 wave crest and wave trough distance first excitation coil 111 and second excitation coil 112 respectively is 0.5mm.Corresponding code disc is provided with M code way copper foil array 21 and N code way copper foil array 22, and the copper foil array is placed in annular by sector metal copper foil and insulating medium spacing, and M code way copper foil array 21 and N code way copper foil array 22 and coil board M code way 121 and N code way 122 one to one correspondence.Inductive encoder's working condition rotor and stator need concentric placement, and M code way copper foil array 21 on code disc 2 is on coil board 1 M code way induction coil 121 and covers the projection of the edge arc of sector copper foil respectively overlaps first excitation coil 111 and second excitation coil 112.N code way copper foil array 122 is on coil board 1 N code way induction coil 122 and covers the projection of the edge arc of sector copper foil but does not overlap second excitation coil 112, but maintains 0.4mm gap, but sector copper foil edge arc overlaps third excitation coil 113.
[0033] The above is only the preferred embodiment of the utility model, the protection scope of the utility model is not only limited to the above-mentioned embodiment, and all technical schemes under the thought of the utility model belong to the protection scope of the utility model for the technical field of the utility model. It should be noted that for ordinary skilled in the art, under the premise of not departing from the principle of the utility model, a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the utility model.
Claims
1. An inductive encoder sensing assembly comprising a coil board and a rotor disc concentrically and parallelly arranged, characterized in that, the coil board comprises: a coil substrate, which is a circular ring PCB multilayer board; excitation coils, including a first excitation coil and a second excitation coil, which are connected in series by PCB leads and layer changing holes and are concentrically drawn on the coil substrate at different diameters, and are compensatively arranged at 180° symmetrical positions with the center of the coil substrate as the center; sensing coils, including M sensing coils and N sensing coils, wherein the M sensing coils are located between the first excitation coil and the second excitation coil, the N sensing coils are located inside the second excitation coil, and the M sensing coils and the N sensing coils are connected to the sensing signal by PCB leads and layer changing holes, and are compensatively arranged at 180° symmetrical positions with the center of the coil substrate as the center; the rotor disc comprises: a disc substrate, which is a circular ring PCB board; an M code copper foil array, which is arranged on the disc substrate, is uniformly spaced in the circumferential direction by a first metal copper foil and an insulating medium, and is opposite to the M sensing coils; 2. An inductive encoder sensing assembly according to claim 1, wherein, an N code copper foil array, which is arranged on the disc substrate, is uniformly spaced in the circumferential direction by a second metal copper foil and an insulating medium, and is opposite to the N sensing coils.
3. An inductive encoder sensing assembly according to claim 1, wherein, The excitation coils further comprise a third excitation coil, which is arranged inside the N sensing coil and is connected in series with the second excitation coil by PCB leads and layer changing holes, and is compensatively arranged at 180° symmetrical positions with the center of the coil substrate as the center.
4. An inductive encoder sensing assembly according to claim 1, wherein, The circular ring PCB multilayer board is a 4-layer board, a 6-layer board or an 8-layer board.
5. An inductive encoder sensing assembly according to claim 1, wherein, The compensative arrangement is a via hole or a supplementary pad.
6. An inductive encoder sensing assembly according to claim 1, wherein, The height of the first metal copper foil is greater than or equal to the distance from the first excitation coil to the second excitation coil.
7. An inductive encoder sensing assembly according to claim 1, wherein, The distance between the N sensing coil and the second excitation coil is greater than 0.7 mm.
8. An inductive encoder sensing assembly according to claim 1, wherein, The number of periods of the M sensing coil and the N sensing coil are different and relatively prime, wherein the number of periods of the M sensing coil is greater than the number of periods of the N sensing coil.
9. An inductive encoder sensing assembly according to claim 8, wherein, The M sensing coil and the N sensing coil each comprise four sinusoidal curves under polar coordinates, the sinusoidal curves are based on 0° phase, and the phase difference is 90°, 180° and 270°, wherein the 0° and 180° curves generate SIN sensing coil signals, and the 90° and 270° curves generate COS sensing coil signals.
10. An inductive encoder sensing assembly according to claim 1, wherein, The sinusoidal curves are symmetrically and alternately distributed on adjacent layers of the PCB, and the sinusoidal curves on different layers are connected together at the wave crests and troughs by layer changing holes. The M code copper foil array and the N code copper foil array respectively contain different numbers of copper foils, and the number of copper foils of the M code copper foil array is greater than the number of copper foils of the N code copper foil array.