Inductance type displacement sensor for magnetic suspension bearing

Abstract

The utility model discloses an inductive displacement sensor for a magnetic suspension bearing, which comprises a stator iron core, and the stator iron core comprises a first detection tooth group and a second detection tooth group which are used for detecting the radial displacement of a rotor, and a third detection tooth group which is used for detecting the axial displacement of the rotor. The axis of the stator core is taken as an original point, the second direction is taken as an axis in the stator core, and the first detection tooth groups in the two quadrants on one side are symmetrical to the first detection tooth groups in the two quadrants on the other side; with the first direction as an axis, the second detection tooth groups in the two quadrants on one side are symmetrical to the second detection tooth groups in the two quadrants on the other side; the first detection tooth set, the second detection tooth set and the axial detection tooth set are all sleeved with frameworks, and each framework is wound with a coil. The sensor adopts a single-layer structure, upper and lower layers of iron cores for axial displacement detection are combined into one layer of iron core and share the iron core with the radial layer, so that the purposes of simple structure, improvement of assembly efficiency and reduction of cost are achieved.

Description

Technical Field

[0001] The utility model relates to an inductive displacement sensor for a magnetic suspension bearing, belonging to the technical field of magnetic suspension. Background Art

[0002] Inductive displacement sensors detect the displacement of an object by converting changes in inductance caused by its displacement into a voltage signal. When used in high-speed magnetic levitation motors, they can monitor the position of the suspended rotor in space and confirm whether it is centered. Because the rotor can move up and down, left and right, and forward and backward, it is necessary to simultaneously detect changes in the rotor's displacement in both the radial and axial directions. Furthermore, magnetic levitation high-speed motors generally have limitations on their axial length, so displacement sensors integrate radial and axial monitoring to reduce the axial length.

[0003] In existing magnetic bearing systems, inductive displacement sensors generally adopt a three-layer structure. The middle layer of iron core and winding detects the radial displacement of the rotor, and the upper and lower layers of iron core and winding detect the axial displacement of the rotor. This structure requires the use of two types of iron core punchings, which increases mold costs. In addition, the upper and lower layers of coils overlap in the axial direction, causing interference during the assembly process and reducing assembly efficiency. Utility Model Content

[0004] The purpose of the utility model is to provide an inductive displacement sensor for magnetic bearings. The sensor adopts a single-layer structure, merges the upper and lower iron cores used for axial displacement detection into a single iron core, and shares the iron core with the radial layer, so as to achieve the purpose of simple structure, improved assembly efficiency and reduced cost. At the same time, the detection tooth groups in different directions can be powered in parallel, and the circuit connections are independent of each other and do not affect each other, which can improve the anti-interference performance of the detection.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present utility model is:

[0006] An inductive displacement sensor for a magnetic bearing includes a stator core, the stator core including an upper stator core and a lower stator core that are stacked, each including an annular stator yoke and a plurality of first stator teeth and a plurality of second stator teeth disposed within the stator yoke ring body, the number of the first stator teeth being ≥10 and being an even number, and the number of the second stator teeth being ≥2;

[0007] The radial length of the second stator teeth is less than the radial length of the first stator teeth; the first stator teeth and the second stator teeth in the same stator yoke are equiangularly spaced and arranged toward the ring center of the stator yoke, and the second stator teeth are symmetrically distributed within the stator yoke ring body about the axial centerline of the stator yoke; the second stator teeth in the upper stator core do not overlap with the second stator teeth in the lower stator core;

[0008] The two overlapping first stator teeth form a radial detection tooth group for detecting radial displacement of the rotor, and the overlapping first stator teeth and second stator teeth form an axial detection tooth group for detecting axial displacement of the rotor; the radial detection tooth group includes a first detection tooth group arranged along a first direction and a second detection tooth group arranged along a second direction; the axial detection tooth group includes a third detection tooth group arranged along a third direction; with the axis of the stator core as the origin, the first direction and the second direction are radial directions of the stator yoke and are perpendicular to each other, and the third direction is the axial direction of the stator core and is perpendicular to the first direction and the second direction;

[0009] With the axis of the stator core as the origin, within the stator core, with the second direction as the axis, the first detection tooth groups in the two quadrants on one side are symmetrical with the first detection tooth groups in the two quadrants on the other side; with the first direction as the axis, the second detection tooth groups in the two quadrants on one side are symmetrical with the second detection tooth groups in the two quadrants on the other side;

[0010] A skeleton is sleeved outside the first detection tooth group, the second detection tooth group and the third detection tooth group, and a coil is wound around each skeleton.

[0011] Preferably, the upper stator core and the lower stator core are both formed by stacking a plurality of stator punching sheets.

[0012] Preferably, the frame has a groove, and the coil is wound in the groove.

[0013] Preferably, the free end of the first stator tooth extends to the outside of the frame, and the free end of the second stator tooth is flush with the outer end of the frame or extends to the outside of the frame.

[0014] Preferably, the stator teeth set and the frame are interference fit.

[0015] Preferably, the first stator teeth and the second stator teeth have the same tooth width and thickness.

[0016] Preferably, the stacked stator punching sheets are welded to form an upper stator core or a lower stator core.

[0017] Preferably, the upper stator core and the lower stator core are welded into one body.

[0018] The beneficial effects of the present invention are:

[0019] This magnetic bearing inductive displacement sensor features a simple structure, high assembly efficiency, and a shorter axial length. The upper and lower stator cores use the same punching laminations, reducing the number of punching dies and lowering procurement and manufacturing costs. Compared to a three-layer structure, a single-layer structure has a shorter axial length. Furthermore, the fewer coils and the larger spacing between them improve assembly efficiency and save time. Furthermore, detection gears in different directions can be powered in parallel, with independent circuit connections that do not affect each other, improving the detection's anti-interference capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the inductive displacement sensor;

[0021] Figure 2 Schematic diagram of the structure of the stator core;

[0022] Figure 3 Schematic diagram of the structure of the stator punching;

[0023] Figure 4 This is the working circuit diagram of the inductive displacement sensor when detecting the rotor position.

[0024] The main reference numerals in the figures have the following meanings:

[0025] 1. Stator core, 2. Upper stator core, 3. Lower stator core, 4. Stator punching sheet, 5. Stator yoke, 6. First stator tooth, 7. Second stator tooth, 8. First detection tooth group, 9. Second detection tooth group, 10. Third detection tooth group, 11. Skeleton, 12. Coil. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] This embodiment provides an inductive displacement sensor for a magnetic bearing. Figure 1 、 2 As shown in Figures 3 and 4, the stator core 1 includes a stator core 1, which includes a stacked upper stator core 2 and a lower stator core 3. Each of the upper stator core 2 and the lower stator core 3 is formed by stacking and welding 12 stator laminations 4 of the same specifications, and the upper stator core 2 and the lower stator core 3 are welded together. The upper stator core 2 and the lower stator core 3 each include an annular stator yoke 5 and a plurality of first stator teeth 6 and a plurality of second stator teeth 7 disposed within the annular body of the stator yoke 5. The number of first stator teeth 6 is ≥10 and is an even number, and the number of second stator teeth 7 is ≥2.

[0028] The radial length of the second stator tooth 7 is smaller than the radial length of the first stator tooth 6, but the tooth width and thickness are the same; the first stator teeth 6 and the second stator teeth 7 in the same stator yoke 5 are distributed at equal angles and arranged toward the ring center of the stator yoke 5, and the second stator teeth 7 are symmetrically distributed in the ring body of the stator yoke 5 about the axial center line of the stator yoke 5; the second stator teeth 7 in the upper stator core 2 do not overlap with the second stator teeth 7 in the lower stator core 3.

[0029] The two overlapping first stator teeth 6 constitute a radial detection tooth group for detecting the radial displacement of the rotor, and the overlapping first stator teeth 6 and second stator teeth 7 constitute an axial detection tooth group for detecting the axial displacement of the rotor; the radial detection tooth group includes a first detection tooth group 8 arranged along the first direction and a second detection tooth group 9 arranged along the second direction; the axial detection tooth group includes a third detection tooth group 10 arranged along the third direction; with the axis of the stator core as the origin, the first direction and the second direction are the radial directions of the stator yoke 5 and are perpendicular to each other, and the third direction is the axial direction of the stator core and is perpendicular to the first direction and the second direction.

[0030] Taking the axis of the stator core as the origin, inside the stator core, with the second direction as the axis, the first detection tooth groups 8 in the two quadrants on one side are symmetrical with the first detection tooth groups 8 in the two quadrants on the other side; with the first direction as the axis, the second detection tooth groups 9 in the two quadrants on one side are symmetrical with the second detection tooth groups 9 in the two quadrants on the other side.

[0031] A skeleton 11 (interference fit) is provided outside the first detection tooth group 8, the second detection tooth group 9 and the third detection tooth group 10. Each skeleton 11 has a groove, and a coil 12 is wound in the groove; wherein the free end of the first stator tooth 6 extends to the outside of the skeleton 11, and the free end of the second stator tooth 7 is flush with the outer port of the skeleton 11.

[0032] For details, see Figure 2 As shown, taking the Cartesian coordinate system as an example, the axis center of the stator core is taken as the origin, the first direction is the X-axis direction, the second direction is the Y-axis direction, and the axial direction is the Z-axis direction. The first stator teeth 6 and the second stator teeth 7 in the same stator yoke 5 are distributed at equal angles (22.5°) and are arranged toward the center of the stator yoke 5.

[0033] A first detection tooth group 8X11 for detecting the positive X direction is distributed in the first quadrant, another first detection tooth group 8X12 for detecting the positive X direction is distributed in the fourth quadrant, and first detection tooth groups 8X21 and X22 for detecting the negative X direction are distributed in the second and third quadrants, respectively. X11 and X12 are symmetrical with X21 and X22 about the Y axis. In actual applications, the number of first detection tooth groups 8 in the two quadrants for detecting the positive X direction can be the same or different, but the distribution of the first detection tooth groups 8 in the two quadrants for detecting the negative X direction must be symmetrical about the Y axis with respect to the distribution of the first detection tooth groups 8 in the two quadrants for detecting the positive X direction.

[0034] Furthermore, a second detection tooth group 9 (Y11) for detecting the positive Y direction is distributed in the second quadrant, another second detection tooth group 9 (Y12) for detecting the positive Y direction is distributed in the first quadrant, and second detection tooth groups 9 (Y21, Y22) for detecting the negative X direction are distributed in the third and fourth quadrants, respectively, wherein Y11, Y12 and Y21, Y22 are symmetrical about the X-axis; in actual application, the number of second detection tooth groups 9 in the two quadrants for detecting the positive Y direction may be the same or different, but the distribution of the second detection tooth groups 9 in the two quadrants for detecting the negative Y direction must be symmetrical about the X-axis with the distribution of the first detection tooth groups 8 in the two quadrants for detecting the positive Y direction.

[0035] Furthermore, each quadrant is provided with a third detection tooth group 10 (Z11, Z12, Z13, and Z14) for detecting the negative Z direction, and a third detection tooth group 10 (Z21, Z22, Z23, and Z24) for detecting the positive Z direction. In actual applications, as long as the distribution requirements of the first detection tooth group 8 in the positive and negative X and Y directions are met, and the number of the first stator teeth 6 is ≥10 and an even number, and the number of the second stator teeth 7 is ≥2, there are no special requirements for the distribution of the third detection tooth group 10.

[0036] The coils 12 on the positive X direction detection gear groups X11 and X12 are connected in series to form the X+ detection winding. Figure 4 The circuit diagram shows X+, with the remaining X-, Y+, Y-, Z+, and Z- being similar. X+ and X- are connected in series, and a sinusoidal or pulsed voltage with an amplitude of 5 to 20V and a frequency of 5k to 50kHz is applied to form an X-direction displacement detection circuit. By detecting the voltage Vx between X+ and X-, the X-direction displacement can be determined (the detection method is conventional and will not be repeated here). The remaining directions are similar. Using this embodiment, the rotor displacement in different directions can be detected, thereby determining the rotor position.

[0037] The above is only a preferred embodiment of the present utility model patent. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present utility model patent. These improvements and modifications should also be regarded as the scope of protection of the present utility model patent.

Claims

1. An inductive displacement sensor for a magnetic bearing, characterized in that: The stator core includes an upper stator core and a lower stator core that are stacked together. The upper stator core and the lower stator core each include an annular stator yoke and a plurality of first stator teeth and a plurality of second stator teeth disposed within the stator yoke ring. The number of the first stator teeth is ≥10 and is an even number, and the number of the second stator teeth is ≥2. The radial length of the second stator teeth is less than the radial length of the first stator teeth; the first stator teeth and the second stator teeth in the same stator yoke are equiangularly spaced and arranged toward the ring center of the stator yoke, and the second stator teeth are symmetrically distributed within the stator yoke ring body about the axial centerline of the stator yoke; the second stator teeth in the upper stator core do not overlap with the second stator teeth in the lower stator core; The two overlapping first stator teeth form a radial detection tooth group for detecting radial displacement of the rotor, and the overlapping first stator teeth and second stator teeth form an axial detection tooth group for detecting axial displacement of the rotor; the radial detection tooth group includes a first detection tooth group arranged along a first direction and a second detection tooth group arranged along a second direction; and the axial detection tooth group includes a third detection tooth group arranged along a third direction; With the axis of the stator core as the origin, the first direction and the second direction are radial directions of the stator yoke and are perpendicular to each other, and the third direction is the axial direction of the stator core and is perpendicular to the first direction and the second direction; With the axis of the stator core as the origin, within the stator core, with the second direction as the axis, the first detection tooth groups in the two quadrants on one side are symmetrical with the first detection tooth groups in the two quadrants on the other side; with the first direction as the axis, the second detection tooth groups in the two quadrants on one side are symmetrical with the second detection tooth groups in the two quadrants on the other side; A skeleton is sleeved outside the first detection tooth group, the second detection tooth group and the third detection tooth group, and a coil is wound around each skeleton.

2. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: The upper stator core and the lower stator core are both formed by stacking a number of stator punching sheets.

3. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: The frame has a groove, and the coil is wound in the groove.

4. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: The free end of the first stator tooth extends to the outside of the frame, and the free end of the second stator tooth is flush with the outer end of the frame or extends to the outside of the frame.

5. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: There is interference fit between the stator tooth group and the frame.

6. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: The first stator teeth and the second stator teeth have the same tooth width and thickness.

7. The inductive displacement sensor for magnetic bearing according to claim 2, characterized in that: The stacked stator punchings are welded to form an upper stator core or a lower stator core.

8. The inductive displacement sensor for magnetic bearing according to claim 1, characterized in that: The upper stator core and the lower stator core are welded into one body.

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