Testing tool for magnetic conduction of stator core of rotary transformer

Abstract

The utility model discloses a tool for testing magnetic conduction of a stator core of a rotary transformer, and belongs to the technical field of rotary transformer testing. The device is characterized in that the device comprises a rotor tool (1), the rotor tool (1) is concentrically and rotatably arranged in a center hole of a to-be-detected iron core (2), a plurality of teeth are uniformly arranged on the outer ring of the rotor tool (1), and the number of the teeth on the outer ring of the rotor tool (1) is the same as the number of stator teeth of the to-be-detected iron core (2). And an excitation winding (4) and an output winding (5) are wound on the surface of each tooth of the outer ring of the rotor tool (1). In the tool for testing the magnetic permeability of the stator core of the rotary transformer, the magnetic permeability of the to-be-tested iron core is tested according to the output value of the induced voltage in the output winding by utilizing the principle that the induced voltage in the output winding only depends on the magnetic permeability and only the to-be-tested iron core only influences the magnetic permeability; and the situation that the output of the rotary transformer is abnormal due to inconsistent magnetic conduction of the iron core to be tested is avoided.

Description

Technical Field

[0001] A test fixture for testing the magnetic conductivity of the stator core of a rotary transformer belongs to the field of rotary transformer testing technology. Background Technology

[0002] A rotary transformer is a common electromechanical sensor that converts mechanical rotation into electrical signals, often used to measure parameters such as angle and speed. Its working principle is based on electromagnetic induction and the mutual inductance principle of transformers: a rotary transformer consists of a stator and a rotor. The stator typically has two windings: a primary winding and an output winding, while the rotor also has two windings: a sine winding and a cosine winding. The primary winding is excited by a sinusoidal voltage or current, generating a rotating magnetic field. This rotating magnetic field induces an electromotive force in the rotor windings. Due to the orthogonality of the rotor windings, the output windings induce two orthogonal voltage signals, one proportional to the sine of the rotor position and the other proportional to the cosine of the rotor position. By measuring the ratio of these two orthogonal output voltages, the angle of the rotor relative to the stator can be obtained. This is because the sine and cosine functions are orthogonal, and their ratio can be used to determine the angle.

[0003] Based on the working principle of rotary transformers, the consistency of the stator core's magnetic conductivity plays a crucial role in the output signal of the rotary transformer during manufacturing. Inconsistencies in the magnetic conductivity of the raw materials or residual magnetism generated within the core due to external forces during subsequent machining processes such as riveting can lead to variations in the stator core's consistency. If the stator core itself exhibits inconsistent magnetic conductivity, it will further affect the rotary transformer's output value. Therefore, designing a technical solution to detect the magnetic conductivity consistency of the rotary transformer stator core has become an urgent problem to be solved in this field. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a test fixture for the magnetic conductivity of the stator core of a rotary transformer that utilizes the principle that the induced voltage in the output winding depends only on the magnetic permeability, and the only factor affecting the magnetic permeability is the iron core under test. By measuring the output value of the induced voltage in the output winding, the magnetic permeability of the iron core under test is tested, thus avoiding abnormal output conditions of the rotary transformer caused by inconsistent magnetic permeability of the iron core under test.

[0005] The technical solution adopted by this utility model to solve its technical problem is: the test fixture for the magnetic conductivity of the stator core of the rotary transformer is characterized by: including a rotor fixture, the rotor fixture is concentrically arranged with the core to be tested, the rotor fixture is rotatably arranged in the central hole of the core to be tested, a number of teeth are evenly arranged on the outer ring of the rotor fixture, the number of teeth on the outer ring of the rotor fixture is the same as the number of stator teeth of the core to be tested, and an excitation winding and an output winding are wound on the surface of each tooth on the outer ring of the rotor fixture.

[0006] Preferably, the rotor tooling includes a test rotor and a frame covering the outside of the test rotor, wherein the frame teeth on the outer ring of the frame cover the rotor teeth on the outer periphery of the test rotor to form the teeth on the outer ring of the rotor tooling.

[0007] Preferably, the skeleton includes a first skeleton and a second skeleton arranged symmetrically, the first skeleton and the second skeleton include an annular skeleton frame, and the skeleton teeth are evenly arranged on the outer ring of the skeleton frame.

[0008] A groove is provided in the middle of each skeleton tooth, and the grooves in the middle of the skeleton teeth of the first and second skeletons are joined to form a space to accommodate the rotor teeth.

[0009] Preferably, the output winding is arranged on the outer ring of the excitation winding.

[0010] Preferably, the gap between the outer wall of the rotor tooling and the inner wall of the iron core to be tested is less than or equal to 0.5 mm.

[0011] Preferably, a chassis is also provided, and the iron core to be tested is placed inside the chassis.

[0012] Preferably, the chassis includes a disc body for accommodating the iron core to be tested, with a turntable located at the center of the disc body, and a rotor fixture mounted on the outer ring of the turntable.

[0013] Preferably, a rotor slot is provided on the inner wall of the center hole of the rotor tooling, and a turntable protrusion is provided on the outer wall of the turntable to engage with the rotor slot.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] In this test fixture for the magnetic permeability of the stator core of a rotary transformer, the principle that the induced voltage in the output winding depends only on the magnetic permeability, and the only factor affecting the magnetic permeability is the core under test, is utilized. By measuring the output value of the induced voltage in the output winding, the magnetic permeability of the core under test is tested, thus avoiding abnormal output conditions of the rotary transformer caused by inconsistent magnetic permeability of the core under test.

[0016] In the test fixture for the magnetic conduction of the stator core of this rotary transformer, a turntable is set at the center of the chassis, and the rotor fixture is clamped on the outside of the turntable to ensure the concentricity of the rotor fixture when rotating. Attached Figure Description

[0017] Figure 1 Isometric view of a test fixture for conducting magnetic flux through the stator core of a rotary transformer.

[0018] Figure 2 Front view of the test fixture for conducting magnetic flux to the stator core of a rotary transformer.

[0019] Figure 3 Exploded view of the test fixture for conducting magnetism on the stator core of a rotary transformer.

[0020] Figure 4 Axonometric view of the test fixture frame for conducting magnetic flux to the stator core of a rotary transformer.

[0021] Figure 5 Test tooling for conducting magnetic flux through the stator core of a rotary transformer; rotor isometric view.

[0022] Figure 6 The test tool for conducting magnetic flux to the stator core of a rotary transformer is shown in the front view of the test rotor.

[0023] Figure 7 Axonometric drawing of the test fixture chassis for conducting magnetic flux to the stator core of a rotary transformer.

[0024] Among them: 1. Rotor fixture 2. Iron core to be tested 3. Chassis 4. Excitation winding 5. Output winding 6. First frame 7. Second frame 8. Test rotor 9. Frame body 10. Frame teeth 11. Frame slot 12. Rotor teeth 13. Rotor slot 14. Rotor disk 15. Turntable protrusion 16. Turntable 17. Disk body. Detailed Implementation

[0025] Figures 1-7 This is the preferred embodiment of the present invention, which is described below in conjunction with the appendix. Figures 1-7 The present invention will be further described below.

[0026] like Figures 1-2 As shown, a test fixture for the magnetic conductivity of a rotary transformer stator core (hereinafter referred to as the test fixture) includes a chassis 3. The core 2 to be tested is placed inside the chassis 3. A rotor fixture 1 is positioned at the center hole of the core 2. The chassis 3, the core 2 to be tested, and the rotor fixture 1 are concentrically arranged, and the rotor fixture 1 is rotatably positioned at the center of the core 2. Multiple teeth are evenly arranged on the outside of the rotor fixture 1, and the number of teeth on the outside of the rotor fixture 1 is the same as the number of teeth on the inner ring stator of the core 2 to be tested. In this test fixture, a 14-tooth example is used for further explanation:

[0027] Combination Figure 3The rotor fixture 1 includes a test rotor 8, and a frame 6 and a second frame 7 are respectively provided in front of and behind the test rotor 8. The first frame 6 and the second frame 7 are fitted together in front of and behind each other to form an internal receiving cavity. The test rotor 8 is located in the receiving cavity formed by the first frame 6 and the second frame 7.

[0028] After the first frame 6 and the second frame 7 are connected and wrapped around the outside of the test rotor 8, multiple excitation windings 4 are evenly arranged on the outer ring of the first frame 6 and the second frame 7, and an output winding 5 is also provided on the outer surface of each excitation winding 4.

[0029] The first frame 6 and the second frame 7 have the same structure, and the first frame 6 and the second frame 7 are symmetrically arranged within the rotor tooling 1. The structures of the first frame 6 and the second frame 7 are as follows: Figure 4 As shown: The first frame 6 (second frame 7) includes an annular frame body 9, with multiple (14) frame teeth 10 evenly arranged on the outside of the frame body 9, and a frame groove 11 is formed in the middle of each frame tooth 10. Both the first frame 6 and the second frame 7 are made of insulating material.

[0030] The skeleton grooves 11 in the middle of all skeleton teeth 10 are located on the same side of the first skeleton 6 (second skeleton 7). Therefore, when the first skeleton 6 and the second skeleton 7 are fitted together in a symmetrical relationship, the skeleton grooves 11 in the middle of the corresponding skeleton teeth 10 of the first skeleton 6 and the second skeleton 7 connect to form a receiving space.

[0031] like Figures 5-6 As shown, the test rotor 8 includes an annular rotor disk 14, which is made of a magnetically conductive material, such as iron. Multiple (14) rotor teeth 12 are evenly arranged on the outside of the rotor disk 14, and rotor slots 13 are formed on the inner wall of the opening in the center of the rotor disk 14. After the first frame 6 and the second frame 7 are symmetrically fitted together, the rotor teeth 12 on the outer ring of the rotor disk 14 are located one-to-one within the corresponding receiving space formed by each set of the first frame 6 and the second frame 7, and the rotor disk 14 is located within the central hole of the first frame 6 and the second frame 7, thus achieving the covering of the rotor teeth 12 by the first frame 6 and the second frame 7.

[0032] The excitation winding 4 is wound around the surface of each set of mating skeleton teeth 10, and the output winding 5 is wound around the surface of each excitation winding 4.

[0033] Combination Figure 7The chassis 3 includes a disc body 17, with an axial protrusion forming around its periphery. This protrusion creates a circular space on the surface of the disc body 17 to accommodate the iron core 2 to be tested. A turntable 16 is rotatably mounted at the center of the disc body 17. A turntable protrusion 15 is provided on the outer wall of the turntable 16. The outer diameter of the turntable 16 matches the inner diameter of the center hole of the rotor disc 14, ensuring that the center hole of the rotor disc 14 can be fitted snugly onto the outside of the turntable 16. When the rotor disc 14 and the turntable 16 are assembled, the turntable protrusion 15 on the surface of the turntable 16 is correspondingly engaged into the rotor slot 13 at the center of the rotor disc 14. The chassis 3 is preferably made of a non-magnetic metal material, such as aluminum.

[0034] The specific working process and working principle are as follows:

[0035] A test rotor 8 with the same number of teeth as the iron core 2 under test is selected, and a test rotor 8 with a suitable outer diameter is selected according to the inner diameter of the iron core 2 under test. The simulation results show that when the gap between the outer wall of the test rotor 8 and the inner wall of the iron core 2 under test is less than or equal to 0.5 mm, the magnetic leakage caused by the gap between the test rotor 8 and the iron core 2 under test will not affect the test results.

[0036] Then, a first frame 6 and a second frame 7, matching the number of teeth and size of the test rotor 8, are selected. After the first frame 6 and the second frame 7 are mated together, the test rotor 8 is encased within them. Then, an excitation winding 4 and an output winding 5 are sequentially arranged outside each frame tooth 10 to form a rotor fixture 1. Next, the iron core 2 to be tested is placed inside the chassis 3, and the rotor fixture 1 is placed inside the iron core 2. The turntable protrusion 15 on the surface of the turntable 16 is then fitted into the rotor slot 13 at the center of the rotor disk 14, assembling the rotor into a complete unit. Figures 1-2 The structure shown.

[0037] During testing, the rotor fixture 1 is rotated. Since the rotor fixture 1 rotates around the turntable 16 inside the chassis 3, it rotates concentrically inside the iron core 2 under test. Simultaneously, a high-frequency excitation current I is passed through the excitation winding 4. f The excitation magnetomotive force generates the main magnetic flux in the air gap.

[0038]

[0039] Where F represents magnetomotive force, N1 represents the number of turns of excitation winding 4, μ represents the permeability of the magnetic material, R represents magnetic reluctance, S represents the coupling area of ​​the air gap magnetic circuit between the core 2 under test and the rotor fixture 1, and δ represents the length of the air gap magnetic circuit between the core 2 under test and the rotor fixture 1.

[0040] High-frequency excitation current I fMost of the main magnetic flux forms a closed loop through the test fixture rotor and the core of the test instrument, therefore the high-frequency excitation current I f The change in flux causes a change in the main magnetic flux, which in turn induces a voltage E in the output winding 5. A :

[0041]

[0042] φ f =M f I f

[0043] Where N2 represents the number of turns in output winding 5, I f φ represents the high-frequency excitation current flowing through excitation winding 4. f Represents the magnetic flux passing through a conductor. The leakage flux representing the presence of the air gap. This represents the main magnetic flux generated in the air gap by the excitation magnetomotive force. M f The proportional constant, known as the mutual inductance coefficient between excitation winding 4 and output winding 5, is M. f It is equal to the mutual inductance flux H passing through the output winding when a unit current flows through the excitation winding 4.

[0044] Due to φ f =M f I f And the main magnetic flux It equals the magnetomotive force generated by excitation winding 4 divided by the magnetic reluctance R along the path of mutual inductance flux, neglecting the influence of leakage flux, that is:

[0045]

[0046] Where, λ 21 The permeability represents the path of the mutual inductance flux, and is the reciprocal of the corresponding magnetic reluctance R. N1 represents the number of turns in the excitation winding 4, and N2 represents the number of turns in the output coil 5.

[0047] As can be seen from the above, a voltage E is induced in the output winding 5. A The change depends only on the permeability λ of the path traversed by the mutual inductance flux. 21 Since the rotor fixture 1 is made of the same material and the air gap between the rotor fixture 1 and the iron core 2 under test is the same, the only factor affecting the magnetic permeability λ is... 21 Only the iron core 2 to be tested is available. Therefore, the output voltage E can be used as a reference. A The error is used to determine whether the core material of the iron core 2 under test meets the requirements.

[0048] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A testing fixture for the magnetic conductivity of a rotary transformer stator core, characterized in that: The device includes a rotor fixture (1), which is concentrically set with the iron core (2) to be tested. The rotor fixture (1) is rotatably set in the center hole of the iron core (2) to be tested. Several teeth are evenly arranged on the outer ring of the rotor fixture (1). The number of teeth on the outer ring of the rotor fixture (1) is the same as the number of stator teeth on the iron core (2) to be tested. Excitation winding (4) and output winding (5) are wound on the surface of each tooth on the outer ring of the rotor fixture (1).

2. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 1, characterized in that: The rotor fixture (1) includes a test rotor (8) and a frame covering the outside of the test rotor (8). The frame teeth (10) of the outer ring of the frame cover the rotor teeth (12) on the outer periphery of the test rotor (8) to form the teeth of the outer ring of the rotor fixture (1).

3. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 2, characterized in that: The skeleton includes a first skeleton (6) and a second skeleton (7) arranged symmetrically. The first skeleton (6) and the second skeleton (7) include a ring-shaped skeleton frame (9), and skeleton teeth (10) are evenly arranged on the outer ring of the skeleton frame (9). A skeleton groove (11) is provided in the middle of each skeleton tooth (10), and the skeleton grooves (11) in the middle of the skeleton teeth (10) of the first skeleton (6) and the second skeleton (7) are joined to form a space to accommodate the rotor tooth (12).

4. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 1 or 2, characterized in that: The output winding (5) is arranged on the outer ring of the excitation winding (4).

5. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 1, characterized in that: The gap between the outer wall of the rotor fixture (1) and the inner wall of the iron core (2) to be tested is less than or equal to 0.5 mm.

6. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 1, characterized in that: A chassis (3) is also provided, and the iron core (2) to be tested is placed inside the chassis (3).

7. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 6, characterized in that: The chassis (3) includes a disc body (17) for accommodating the iron core (2) to be tested, and a turntable (16) is provided at the center of the disc body (17). The rotor fixture (1) is clamped on the outer ring of the turntable (16).

8. The testing fixture for the magnetic permeability of the stator core of a rotary transformer according to claim 7, characterized in that: A rotor slot (13) is provided on the inner wall of the center hole of the rotor tooling (1), and a turntable protrusion (15) is provided on the outer wall of the turntable (16) to engage with the rotor slot (13).

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