Hollow inductance type encoder

Abstract

The invention discloses a hollow inductance type encoder, and relates to the field of encoders, the hollow inductance type encoder comprises a stator assembly and a rotor assembly which are arranged in parallel and opposite to each other, the stator assembly comprises a stator protection shell, a signal plate and a coil plate, and a first excitation coil, a second excitation coil and a third excitation coil are concentrically arranged on the coil plate. The rotor assembly comprises a rotor protection shell and a code disc, N fan-shaped first copper foils are uniformly arranged on the radial inner side of the code disc in the circumferential direction, the first copper foils are right opposite to the first induction coil, M fan-shaped second copper foils are uniformly arranged on the radial outer side of the code disc in the circumferential direction, the second copper foils are right opposite to the second induction coil, and Mgt; n. Compared with the prior art, the hollow inductance type encoder provided by the invention can adapt to various working conditions, outputs accurate angle values in a high-stability manner, improves the measurement precision, enhances the dynamic performance and stability of a system, and improves the anti-interference capability.

Description

Technical Field

[0001] The invention relates to the field of encoders, and in particular to a hollow inductive encoder. Background Art

[0002] The inductive encoder works based on the principle of electromagnetic induction. The excitation coil generates a high-frequency magnetic field, making the initial differential output of the induction coil zero. When a ferrite or conductor enters, due to the eddy current effect, it generates a reverse magnetic field that interferes with the original magnetic field, causing the output voltage of the induction coil to change. This change is related to the position of the object. After signal processing, the angle, position and other measurement results can be converted. Inductive encoders are widely used in many fields such as industrial automation, automobiles and transportation, aerospace, energy and environmental protection equipment. These fields often face harsh working conditions such as high dust / oil pollution, humid / underwater environment, strong magnetic interference, extreme temperature, etc. The existing hollow inductive encoder is generally composed of a stator and a rotor made of a PCB board. Under harsh working conditions, it may face erroneous output or even damage and stop working. In order to ensure that the encoder can adapt to harsh working conditions, a hollow inductive encoder with high environmental adaptability and high stable output is required. Summary of the invention

[0003] In view of the above problems, the present invention provides a hollow inductive encoder, which is used to solve the problem that the hollow inductive angle encoder in the prior art cannot adapt to various working conditions and is easily damaged.

[0004] The present invention provides a hollow inductive encoder, comprising a stator assembly and a rotor assembly which are arranged in parallel and facing each other, wherein the stator assembly comprises a stator protective shell having an open first annular accommodating cavity; a signal board which is arranged in the first annular accommodating cavity; a coil board which is electrically connected to the signal board, is arranged at the opening of the first annular accommodating cavity and closes the opening, a first excitation coil, a second excitation coil and a third excitation coil which are connected in series through PCB leads and layer-changing holes are concentrically arranged on the coil board, a first induction coil is arranged in the induction space between the first excitation coil and the second excitation coil, a second induction coil is arranged in the induction space between the second excitation coil and the third excitation coil, and the first induction coil and the second induction coil are respectively connected through PCB leads and layer-changing holes. The lead wire and the layer-changing hole lead out the induction signal; the rotor assembly includes a rotor protective shell with an open second annular accommodating cavity; a code disk is arranged at the opening of the second annular accommodating cavity and closes the opening, and N first copper foils are evenly arranged in the circumferential direction on the radial inner side of the code disk, and the first copper foils are directly opposite to the first induction coil, and M second copper foils are evenly arranged in the circumferential direction on the radial outer side of the code disk, and the second copper foils are directly opposite to the second induction coil, wherein M>N.

[0005] Preferably, it further comprises an isolation plate, which is arranged between the signal plate and the coil plate and is welded to the signal plate and the coil plate respectively.

[0006] Preferably, the isolation board is a FR4 blank board.

[0007] Preferably, a plurality of first potting holes are formed at the bottom of the first accommodating cavity; and a plurality of second potting holes are formed at the bottom of the second accommodating cavity.

[0008] Preferably, it further comprises a signal line, the stator protective shell is provided with a line outlet slot, the line outlet slot is located at the outer periphery of the stator protective shell, and the signal line passes through the line outlet slot to be connected with the signal board.

[0009] Preferably, a stator mounting surface is provided on the outer circumference of the stator protective shell, and a plurality of groups of stator mounting holes are provided on the stator mounting surface; a rotor mounting surface is provided on the inner circumference of the rotor protective shell, and a plurality of groups of rotor mounting holes are provided on the rotor mounting surface.

[0010] Preferably, the first induction coil and the second induction coil are both sinusoidally periodic.

[0011] Preferably, the N first copper foils and the M second copper foils are all copper foil rows in which metal copper foils and insulating dielectrics are evenly spaced apart.

[0012] Preferably, in the axial orthographic projection of the rotor assembly on the stator assembly, the second copper foil covers the second induction coil and the upper and lower edge arcs of the second copper foil overlap with the third excitation coil and the second excitation coil respectively, and the first copper foil covers the first induction coil and there is a gap between the edge of the first copper foil and the second excitation coil.

[0013] Preferably, a 180° symmetrical position compensation setting is provided with the center of the coil plate as the center of the circle where the excitation coil is connected in series through the PCB lead and the layer-changing hole; and a 180° symmetrical position compensation setting is provided with the center of the coil substrate as the center of the circle where the induction coil leads out the induction signal through the PCB lead and the layer-changing hole respectively.

[0014] Preferably, the compensation setting is a compensation via or a compensation pad.

[0015] Compared with the prior art, the hollow inductive encoder provided by the present invention can adapt to various working conditions, output accurate angle values ​​with high stability, improve measurement accuracy, enhance system dynamic performance and stability, and improve anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a hollow inductive encoder.

[0017] Figure 2 It is a schematic diagram of the explosion of a hollow inductive encoder.

[0018] Figure 3 It is a cross-sectional schematic diagram of a hollow inductive encoder.

[0019] Figure 4 It is a schematic diagram of the stator protective shell of a hollow inductive encoder.

[0020] Figure 5 It is a schematic diagram of a hollow inductive encoder rotor protective shell.

[0021] Figure 6 It is a schematic diagram of the stator assembly of a hollow inductive encoder.

[0022] Figure 7 It is a schematic diagram of a hollow inductive encoder rotor assembly.

[0023] Description of reference numerals: 1. stator assembly, 11. stator protective shell, 111. first annular accommodating cavity, 112. first potting hole, 113. outlet slot, 114. stator mounting surface, 1141. stator mounting hole, 12. coil plate, 121. first excitation coil, 122. second excitation coil, 123. third excitation coil, 124. first induction coil, 125. second induction coil, 126. compensation via, 13. signal plate, 14. isolation plate; 2. rotor assembly, 21. rotor protective shell, 211. second annular accommodating cavity, 212. second potting hole, 213. rotor mounting surface, 2131. rotor mounting hole, 22. code disc, 221. first copper foil, 222. second copper foil; 3. Signal line. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0025] The embodiment of the present invention discloses a hollow inductive encoder, referring to Figures 1 to 7 A hollow inductive encoder comprises a stator component 1 and a rotor component 2 which are arranged in parallel and opposite to each other, and a signal line 3 led out from the stator component 1, and the rotor component 1 is projected on the stator component 2 in the axial direction. The stator assembly 1 includes a stator protection case 11 , a coil plate 12 , a signal plate 13 and an isolation plate 14 .

[0026] The stator protective shell 11 is made of metal aluminum. A stator mounting surface 114 is designed on the outer peripheral side of the stator protective shell 11. Three groups of stator mounting holes 1141 symmetrically distributed and located on the same circumference are arranged on the stator mounting surface 114. The inner holes of any group of symmetrical stator mounting holes 1141 located on the same diameter are provided with threads for use as disassembly holes, and a wire outlet slot 113 is opened between any two stator mounting holes 1141.

[0027] On the inner side of the stator mounting surface 114 is a first annular accommodating cavity 111 with one end open. The signal board 13 is arranged in the first accommodating cavity 111, and the signal line 3 is introduced into the first accommodating cavity 111 through the outlet groove 113 and connected to the signal board 13. The coil board 12 is arranged at the opening of the first accommodating cavity 111 and the opening is closed. Since the coil board 12 is not provided with a shielding layer, an isolation plate 14 made of a blank FR4 board is arranged between the signal board 13 and the coil board 12 to increase the distance between the signal board 13 and the coil board 12, reduce the influence of the signal board 13 on the coil board 12, and enhance the signal. The size and shape of the isolation plate 14 are consistent with the signal board 13, and are respectively welded to the signal board 13 and the coil board 12 through the pad and the half hole to realize the electrical connection between the coil board 12 and the signal board 13.

[0028] Four first potting holes 112 are symmetrically distributed and located on the same circumference at the bottom of the first annular accommodating cavity 111 facing the opening. The four first potting holes 112 are arranged on the same diameter and are grouped together. Any first potting hole 112 is selected for the entry of liquid epoxy glue. The first potting holes 112 in the same group can balance the air pressure to ensure that the liquid epoxy glue can fill the first annular accommodating cavity 111. The two first potting holes 112 in another group can be used for plane leveling of the stator assembly.

[0029] The coil board 12 adopts a 4-layer circular PCB multilayer board, and a first excitation coil 121, a second excitation coil 122 and a third excitation coil 123 of different diameters connected in series through PCB leads and layer-changing holes are concentrically arranged on the third and fourth layers. Each group of excitation coils is wound in an overlapping manner on each layer, and each layer is wound with three turns of annular coils. The winding directions of two adjacent groups of excitation coils are opposite, and an annular induction space is formed between the two groups of excitation coils; a first induction coil 124 is arranged in the induction space between the first excitation coil 121 and the second excitation coil 122, and a second induction coil 125 is arranged in the induction space between the second excitation coil 122 and the third excitation coil 123. The first induction coil 124 and the second induction coil 125 are both composed of four sinusoidal curves of multiple periods in polar coordinates. The four curves are based on a 0° phase, and have a phase difference of 90°, 180°, and 270°, wherein the number of periods of the first induction coil 124 is less than the number of periods of the second induction coil 125. Each sinusoidal curve is alternately arranged on the third and fourth layers of the coil plate 12, and the layers are changed every half cycle. The first induction coil 124 and the second induction coil 125 both lead out the induction signal through the PCB lead and the layer-changing hole; in order to ensure the symmetry of the coil plate, the compensation via 126 is placed at a 180° symmetrical position with the center of the coil substrate as the center of the circle at the place where the excitation coil is connected in series through the PCB lead and the layer-changing hole and where the induction coil leads out the induction signal through the PCB lead and the layer-changing hole respectively. The size and shape of the compensation via 126 are completely consistent with the size and shape of the layer-changing hole.

[0030] The rotor assembly 2 includes a rotor protection shell 21 and a code disc 22 .

[0031] The rotor protection shell 21 is made of aluminum. A rotor mounting surface 213 is designed on the inner circumference of the rotor protection shell 21. Three groups of symmetrically distributed rotor mounting holes 2131 located on the same circumference are set on the rotor mounting surface 213. The inner holes of any group of symmetrical rotor mounting holes 2131 located on the same diameter are provided with threads for use as disassembly holes. On the outer side of the rotor mounting surface 213 is a second annular accommodating cavity 211 with an opening at one end. The code disc 22 is set at the opening of the second annular accommodating cavity 211 and closes the opening.

[0032] Four second potting holes 212 are symmetrically distributed and located on the same circumference at the bottom of the second annular accommodating cavity 211 opposite to the opening. The second potting holes 212 are distributed and function the same as the first potting holes 112 .

[0033] On the radial inner side of the code disk 22, 45 fan-shaped copper foils are evenly arranged in the circumferential direction as the first copper foil 221. The first copper foil 221 is directly opposite to the first induction coil 124 on the coil plate 12. The orthographic projection of the first copper foil 221 on the coil plate 12 covers the first induction coil 124 but does not overlap with the second excitation coil 122 and the third excitation coil 123. Instead, a gap of 0.1 mm is maintained to generate an eddy current effect.

[0034] On the radial outer side of the code disk 22, 125 fan-shaped copper foils are evenly arranged in the circumferential direction as the second copper foil 222. The second copper foil 222 is directly opposite to the second induction coil 125. The orthographic projection of the second copper foil 222 on the coil plate 12 covers the second induction coil 125, and the edge arcs of the fan-shaped copper foil overlap the first excitation coil 121 and the second excitation coil 112 respectively to generate an eddy current effect.

[0035] The first copper foil 221 and the second copper foil 222 are both copper foil arrays in which metal copper foil and insulating medium are evenly spaced.

[0036] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A hollow inductive encoder, comprising a stator assembly and a rotor assembly arranged in parallel and facing each other, characterized in that: The stator assembly comprises: A stator protective shell having an open first annular accommodating cavity; A signal plate, disposed in the first annular accommodating cavity; A coil plate, electrically connected to the signal plate, disposed at the opening of the first annular accommodating cavity and closing the opening, a first excitation coil, a second excitation coil and a third excitation coil connected in series through PCB leads and layer-changing holes are concentrically disposed on the coil plate, a first induction coil is disposed in the induction space between the first excitation coil and the second excitation coil, a second induction coil is disposed in the induction space between the second excitation coil and the third excitation coil, and the first induction coil and the second induction coil respectively lead out induction signals through the PCB leads and the layer-changing holes; The rotor assembly comprises: A rotor protective shell having an open second annular accommodating cavity; A code disk is arranged at the opening of the second circular accommodating cavity and closes the opening. On the radial inner side of the code disk, N first copper foils are evenly arranged in the circumferential direction, and the first copper foils are directly opposite to the first induction coil. On the radial outer side of the code disk, M second copper foils are evenly arranged in the circumferential direction, and the second copper foils are directly opposite to the second induction coil, wherein M>N.

2. A hollow inductive encoder according to claim 1, characterized in that: It also includes a shielding plate isolation plate, which is arranged between the signal plate and the coil plate and is welded to the signal plate and the coil plate respectively.

3. A hollow inductive encoder according to claim 2, characterized in that: The isolation board is a FR4 blank board.

4. The hollow inductive encoder according to claim 1, characterized in that: It also includes a signal line. The stator protective shell is provided with a line outlet slot, the line outlet slot is located at the outer periphery of the stator protective shell, and the signal line passes through the line outlet slot and is connected to the signal board.

5. The hollow inductive encoder according to claim 1, characterized in that: The stator protective shell is provided with a stator mounting surface on the outer circumference side, and a plurality of groups of stator mounting holes are arranged on the stator mounting surface. The rotor protective shell is provided with a rotor mounting surface on the inner circumference side, and a plurality of groups of rotor mounting holes are arranged on the rotor mounting surface.

6. The hollow inductive encoder according to claim 1, characterized in that: The first induction coil and the second induction coil are both sinusoidally periodic.

7. The hollow inductive encoder according to claim 1, characterized in that: The N first copper foils and the M second copper foils are all copper foil rows in which metal copper foils and insulating dielectrics are evenly spaced.

8. The hollow inductive encoder according to claim 1, characterized in that: In the axial orthographic projection of the rotor assembly on the stator assembly, the second copper foil covers the second induction coil and the upper and lower edge arcs of the second copper foil overlap the third excitation coil and the second excitation coil respectively, and the first copper foil covers the first induction coil and there is a gap between the edge of the first copper foil and the second excitation coil.

9. The hollow inductive encoder according to claim 1, characterized in that: A 180° symmetrical position compensation setting is provided with the center of the coil plate as the center of the circle where the excitation coil is connected in series through the PCB lead and the layer-changing hole; a 180° symmetrical position compensation setting is provided with the center of the coil substrate as the center of the circle where the induction coil leads out the induction signal through the PCB lead and the layer-changing hole respectively.

10. The hollow inductive encoder according to claim 9, characterized in that: The compensation setting is a compensation via or a compensation pad.

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