Rotary transformer

Abstract

Measure the voltage of the second coil with high accuracy. [Solution] A rotary transformer comprising a fixed first magnetic core, a first coil wound around the first magnetic core, a second magnetic core rotatably positioned radially outward from the first magnetic core and facing the first magnetic core, having a shaft portion extending in the direction of the rotation axis and a projection portion projecting radially inward, and a second coil wound around the second magnetic core, wherein a voltage sensor is attached to the outer circumferential surface of the first magnetic core and has a sensor projection portion projecting toward the angle formed by the shaft portion and the projection portion of the second magnetic core.

Description

Technical Field

[0001] The present disclosure relates to a rotary transformer.

Background Art

[0002] Conventionally, as this type of transformer, there has been proposed one including a first magnetic core (inner magnetic core), a first coil (winding) wound around the first magnetic core, a second magnetic core (outer magnetic core) disposed so as to face the first magnetic core on the radially outer side of the first magnetic core, and a second coil (winding) wound around the second magnetic core (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a rotary transformer of a type in which the second coil rotates together with the second magnetic core, accurately measuring the voltage of the second coil has been recognized as an important problem. As a method of measuring the voltage of the second coil, a method of attaching a voltage sensor to the second magnetic core can be considered. However, in this method, since the second magnetic core rotates, it is difficult to route the signal line from the voltage sensor. Also, a method of measuring the voltage of the second coil using a slip ring, radio waves, etc. without attaching a voltage sensor to the second magnetic core can be considered. However, with this method, the voltage of the second coil cannot be accurately measured. The rotary transformer of the present disclosure mainly aims to accurately measure the voltage of the second coil.

[0005] The rotary transformer of the present disclosure mainly aims to accurately measure the voltage of the second coil.

Means for Solving the Problems

[0006] The rotary transformer of this disclosure employs the following means to achieve the primary objective described above.

[0007] The rotary transformer of this disclosure is A fixed first magnetic core, A first coil wound around the first magnetic core, A second magnetic core is rotatably positioned radially outward from the first magnetic core and facing the first magnetic core, and has a shaft portion extending in the direction of the rotation axis and a projection portion projecting radially inward. A second coil is wound around the second magnetic core and rotates together with the second magnetic core, A rotary transformer A voltage sensor having a sensor projection attached to the outer circumferential surface of the first magnetic core and projecting toward the angle formed by the shaft portion and the projection of the second magnetic core. The gist of it is that it is equipped with the following features.

[0008] The rotary transformer of this disclosure includes a voltage sensor attached to the outer circumferential surface of the first magnetic core, having a sensor projection that protrudes toward the angle between the shaft and projection of the second magnetic core. The voltage sensor can measure the voltage of the second coil by detecting the leakage flux at the angle between the shaft and projection. In this way, the voltage of the second coil can be measured with high accuracy using the voltage sensor. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the rotary transformer according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of the main components of a rotary transformer. [Modes for carrying out the invention]

[0010] Embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of a rotary transformer according to an embodiment of the present disclosure. As shown in the figure, the rotary transformer 10 comprises a first magnetic core 20, a first coil 26, a second magnetic core 30, a second coil 36, and a voltage sensor 40, and is configured as a transformer in which the first magnetic core 20 is fixed and the second magnetic core 30 rotates. The rotary transformer 10 is used in a wound field motor. The rotation axis direction and radial direction of the second magnetic core 30 are as shown in Figure 2.

[0011] The first magnetic core 20 is formed as the primary magnetic material of the rotary transformer 10 and is fixed to the stator of the wound field motor. The first magnetic core 20 comprises a first shaft portion 22 that is substantially cylindrical and extends in the direction of the rotation axis, and a first projection portion 24 that is continuous with the first shaft portion 22 and protrudes radially outward from one end of the first shaft portion 22 in the direction of the rotation axis, and has a flange shape.

[0012] The first coil 26 is formed as the primary coil of the rotary transformer 10 and is wound multiple times around the outer circumference of the first shaft portion 22 of the first magnetic core 20. The first coil 26 is connected to the first line L1, which is wiring from the power supply.

[0013] The second magnetic core 30 is rotatably positioned radially outward from the first magnetic core 20 and facing the first magnetic core, and is formed as the secondary magnetic material of the rotary transformer 10. The second magnetic core 30 has a substantially cylindrical shape and includes a second shaft portion (shaft portion) 32 extending in the direction of the rotation axis, and a flange-shaped second projection portion (projection portion) 34 that is continuous with the second shaft portion 32 and protrudes radially inward at the end of the second shaft portion 32 opposite to the first shaft portion 22 in the direction of the rotation axis. The second magnetic core 30 is positioned so as to be rotatable without contacting the first magnetic core 20, the first coil 26, and the voltage sensor 40.

[0014] The second coil 36 is formed as the secondary coil of the rotary transformer 10 and is wound multiple times around the inner circumferential surface of the second shaft portion 32 of the second magnetic core 30. The second coil 36 is connected to the second line L2, which is the wiring from the wound field motor side. The second coil 36 is positioned to rotate together with the second magnetic core 30 without contacting the first magnetic core 20, the first coil 26, and the voltage sensor 40. The second coil 36 is connected to the second line L2, which is the wiring of the wound field motor.

[0015] The voltage sensor 40 is mounted on the outer circumferential surface of the first magnetic core 20, facing the second magnetic core 30 on the radially outer side of the first magnetic core 20. The voltage sensor 40 has a substantially cylindrical shape and includes a sensor shaft portion 42 extending in the direction of the rotation axis, and a sensor projection portion 44 that protrudes toward the angle 38 formed by the second shaft portion 32 and the second projection portion 34 of the second magnetic core 30, without contacting the second projection portion 34. The sensor projection portion 44 includes a sensor coil 46 as a winding, with a portion exposed and the remainder embedded. The sensor coil 46 is connected to a sensor line Ls, which is wiring from the winding field motor side.

[0016] In the rotary transformer 10 configured in this way, the second magnetic core 30 and the first coil 26 rotate, changing the voltage of the AC power applied via the first line L1 and supplying it to the second coil 36.

[0017] Next, the operation of the voltage sensor 40 attached to the rotary transformer 10 in the embodiment configured in this way will be described.

[0018] FIG. 2 is a schematic diagram of a main part of a rotary transformer. In the figure, the thick arrow indicates an example of the direction of magnetic flux passing through the second magnetic core. As shown in FIG. 2, part of the magnetic flux passing through the second magnetic core 30 leaks to the inner peripheral side at the corner 38, crosses the sensor coil 46 of the voltage sensor 四十, and generates an induced current in the sensor coil 46. The voltage sensor 40 detects this induced current as a voltage and detects the voltage of the second coil 36 using a predetermined conversion factor. In this way, by attaching the voltage sensor 40 to the outer peripheral surface of the first magnetic core 20 and providing the sensor coil 46 on the sensor projecting portion 44 that projects toward the corner 38, the voltage of the second coil 36 can be accurately measured.

[0019] According to the rotary transformer 10 of the present embodiment described above, since it includes a voltage sensor 40 attached to the outer peripheral surface of the first magnetic core 20 and having a sensor projecting portion 44 that projects toward the corner 38 formed by the second shaft portion 32 and the second projecting portion 34 of the second magnetic core 30, the voltage of the second coil 36 can be accurately measured.

[0020] In the above-described embodiment, the rotary transformer 10 is used in a wound field magnet motor, but the use of the rotary transformer 10 is not limited to a wound field magnet motor, and it may be used in other devices.

[0021] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the first magnetic core 20 corresponds to the "first magnetic core", the first coil 26 corresponds to the "first coil", the second shaft portion 32 corresponds to the "shaft portion", the second projecting portion 34 corresponds to the "projecting portion", the second coil 36 corresponds to the "second coil", the sensor projecting portion 44 corresponds to the "sensor projecting portion", and the voltage sensor 40 corresponds to the "voltage sensor".

[0022] Note that the correspondence between the main elements of the embodiments and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the column of means for solving the problems in the embodiments. Therefore, it does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiments are merely specific examples of the invention described in the column of means for solving the problems.

[0023] As described above, the embodiments for implementing the present disclosure have been described using the embodiments. However, the present disclosure is not limited to such embodiments, and it is needless to say that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0024] The present disclosure can be used in the manufacturing industry of rotary transformers and the like.

Explanation of Signs

[0025] 10 Rotary transformer, 20 First magnetic core, 22 First shaft portion, 24 First protruding portion, 26 First coil, 30 Second magnetic core, 32 Second shaft portion, 34 Second protruding portion, 36 Second coil, 38 Angle, 40 Voltage sensor, 42 Sensor shaft portion, 44 Sensor protruding portion, 46 Sensor coil, L1 First line, L2 Second line, Ls Sensor line.

Claims

[Claim 1] A fixed first magnetic core, A first coil wound around the first magnetic core, A second magnetic core is rotatably positioned radially outward from the first magnetic core and facing the first magnetic core, and has a shaft portion extending in the direction of the rotation axis and a projection portion projecting radially inward. A second coil is wound around the second magnetic core and rotates together with the second magnetic core, A rotary transformer equipped with, A voltage sensor having a sensor projection attached to the outer circumferential surface of the first magnetic core, and projecting toward the angle formed by the shaft portion and the projection portion of the second magnetic core. A rotary transformer equipped with a rotary transformer.

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