Resistance measuring device and resistance measuring method

Abstract

To provide a resistance measuring device that can suppress the decrease in insulation performance after measuring the insulation resistance of a stator coil. [Solution] The resistance measuring device according to the present invention is a resistance measuring device for measuring the insulation resistance of a stator coil wound around a stator core which is a magnetic material, and comprises a resistance measuring unit for measuring the electrical resistance of a part to be measured, and an electrode connected to the resistance measuring unit via wiring for contacting the conductor of the stator coil, wherein the electrode has a hollow structure, and holes are provided in the hollow structure for injecting resin and for discharging the resin from the inside of the hollow structure.

Description

Technical Field

[0001] The present invention relates to a resistance measuring device and a resistance measuring method for a stator of a rotating electrical machine.

Background Art

[0002] There is known a technique of cutting the insulation coating of a stator coil component with an electrode at the tip of a probe or the like and measuring the insulation resistance between the probe and the stator coil. Patent Document 1 discloses a technique of cutting the insulation coating in a knife scratch shape, connecting an insulation resistance meter between the connector terminal of the coil and the stator core, measuring the insulation resistance value, and making a determination of insulation based on the measurement result.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When joining the stator coil within the core, since the joint portion is not visible, the insulation resistance of the joint portion is ensured by cutting the insulation coating at the coil end of the stator coil and measuring the insulation resistance. In the technique disclosed in Patent Document 1, since the conductor is exposed by cutting the insulation coating, there is a risk that the insulation property after the insulation resistance measurement may deteriorate.

[0005] An object of the present invention is to provide a resistance measuring device capable of suppressing a decrease in the insulation property after measuring the insulation resistance of a stator coil.

Means for Solving the Problems

[0006] The resistance measuring device according to the present invention is a resistance measuring device for measuring the insulation resistance of a stator coil wound around a stator core which is a magnetic material, and comprises a resistance measuring unit for measuring the electrical resistance of a part to be measured, and an electrode connected to the resistance measuring unit via wiring for contacting the conductor of the stator coil, wherein the electrode has a hollow structure, and holes are provided in the hollow structure for injecting resin and for discharging the resin from the inside of the hollow structure. [Effects of the Invention]

[0007] The present invention provides a resistance measuring device that can suppress the decrease in insulation performance after measuring the insulation resistance of a stator coil. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the configuration of a resistance measuring device according to one embodiment of the present invention. [Figure 2] This is a perspective view showing the configuration of a stator according to one embodiment of the present invention. [Figure 3] Figure 2 shows a cross-sectional view of the stator along line III-III. [Figure 4] This diagram illustrates the structure of the stator coil shown in Figure 2. [Figure 5] This is a diagram illustrating a resistance measurement method according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. Note that the drawings are simplified, and the technical scope of the embodiments should not be narrowly interpreted based on their depiction. Furthermore, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. Also, in the following embodiments, when referring to the number of elements (including quantity, numerical value, amount, range, etc.), unless specifically stated or clearly limited to a particular number in principle, the number is not limited to that particular number and may be greater than or less than that number.

[0010] Furthermore, in the following embodiments, the components are not necessarily essential unless otherwise explicitly stated or considered to be clearly essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of the components, etc., it shall include those that substantially approximate or resemble their shape, etc., unless otherwise explicitly stated or considered to be clearly not essential in principle. The same applies to the numbers, etc. (including the number of items, numerical values, quantities, ranges, etc.).

[0011] [Embodiment] <Configuration of Resistance Measuring Device 1> Figure 1 shows the configuration of a resistance measuring device 1 according to one embodiment of the present invention. The resistance measuring device 1 comprises a resistance measuring unit 2 and a probe 4 connected to an electrode 3. The resistance measuring unit 2 and the probe 4 are connected via wiring 2a. The resistance measuring unit 2 comprises a control circuit 5, an indicator 6, and a DC voltage generation circuit 7, to which a clip 8 is connected. The resistance measuring unit 2 measures the electrical resistance of the part to be measured. In this embodiment, the resistance measuring device 1 measures the insulation resistance of the conductor 22a of the stator coil 20, which will be described later using Figure 2, etc., as the part to be measured.

[0012] Furthermore, the probe 4 is equipped with a switch 9, and the electrode 3, which protrudes from the tip of the probe 4, is made to protrude by a spring 3a. In the illustrated example, the switch 9 is provided on the probe 4, but it may also be provided on a component other than the probe 4.

[0013] To measure the insulation resistance, for example, the tip portion 32 of electrode 3 is used to cut through the coating 23a of the stator coil 20, which is the object to be measured for insulation resistance, exposing the conductor 22a. Then, electrode 3 is brought into contact with the exposed conductor 22a to measure the insulation resistance of the stator coil 20. At this time, clip 8 is connected to ground (not shown), and switch 9 provided on probe 4 is pressed.

[0014] Then, by pressing the tip portion 32 of the electrode 3 against the conductor 22a of the stator coil 20, which is the object to be measured, the electrode 3 is retracted against the spring 3a, the terminal 3b of the electrode 3 is connected to the terminal 9a of the switch, and information is transmitted to the control circuit 5. Further, the insulation resistance of the stator coil 20 is measured by displaying the information on the indicator 6 provided in the resistance measurement unit 2.

[0015] In this embodiment, the electrode 3 has a hollow structure provided with a hole 31 for injecting or discharging resin. In addition to the hole 31, the electrode 3 is provided with another hole (not shown) at the tip portion 32. Before measuring the insulation resistance, resin is injected into the hollow structure of the electrode 3. The resin inside the hollow structure is discharged from the hole at the tip portion 32 of the electrode 3. Further, the discharge of the resin is not limited to the hole at the tip portion 32, and may be discharged from the hole 31 on the side surface or the like. Furthermore, the number of the holes 31 is not limited to one, and a plurality of holes may be provided.

[0016] The resin discharged from the tip portion 32 of the electrode 3 is injected into the stator coil 20 so as to cover the exposed conductor 22a. The resin may be, for example, varnish and silicone seal, etc., but is not limited thereto, and any resin having insulation properties may be used. The resin injected into the stator coil 20 contacts the exposed conductor 22a, and the insulation property of the stator coil 20 can be restored. According to the resistance measurement device 1 according to this embodiment, since the resin can be directly injected from the electrode 3 into the stator coil 20 immediately after the resistance measurement, the insulation property of the stator coil 20 can be immediately restored.

[0017] In addition, the electrode 3 is subjected to a surface treatment for preventing the adhesion of resin, at least on the hole 31. The surface treatment is, for example, fluorine coating treatment, etc., but is not limited thereto, and various treatments capable of preventing the adhesion of resin are available. Therefore, the removal of the resin remaining on the electrode 3 can be easily performed.

[0018] Note that the resistance measurement device 1 according to this embodiment is not limited to the configuration shown in FIG. 1, and various configurations can be adopted.

[0019] <Configuration of the stator 100> Here, the configuration of the stator 100 including the stator coil 20 for measuring insulation resistance using the resistance measuring device 1 according to this embodiment will be described with reference to FIGS. 2 to 4. FIG. 2 is a perspective view showing the configuration of the stator 100 according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III of the stator 100 shown in FIG. 2. FIG. 4 is a diagram for explaining the structure of the stator coil 20 shown in FIG. 2.

[0020] As shown in FIGS. 2 and 3, in the stator 100 according to this embodiment, two stator coils 20 are connected by a joint pipe 30 inside a stator core 10 made of a magnetic material. The stator 100 configured in this way is combined with a rotor (not shown) and used as a rotating electric machine mounted on vehicles such as, for example, an electric motor, a generator, a battery electric vehicle (BEV), and a hybrid electric vehicle (HEV).

[0021] The rotating electric machine rotates about the rotation axis C due to the electromagnetic action acting between the rotating magnetic field generated by the flow of current in the stator coil 20 included in the stator 100 and the rotor. Hereinafter, the direction of the rotation axis C will be described as the axial direction.

[0022] The stator core 10 may be configured by laminating a plurality of substantially cylindrical electromagnetic steel sheets. At this time, each electromagnetic steel sheet has substantially the same shape and can be formed by punching or the like. The stator core 10 includes an annular yoke 11 extending along the circumferential direction and a plurality of teeth 12 protruding radially inward from the inner peripheral surface of the yoke 11. The plurality of teeth 12 are arranged at intervals in the circumferential direction, and slots are formed between the teeth 12 adjacent in the circumferential direction.

[0023] The stator coil 20 may include a three-phase stator coil 20. The stator coil 20 is mounted on each tooth 12 through slots between the teeth 12. The stator coil 20 is joined by bending the coil ends 21 that protrude beyond the axial end face of the stator core 10 through slots that are at different circumferential positions from each other in the circumferential direction.

[0024] As shown in Figure 2, the insulation resistance of the stator coil 20 is measured by the resistance measuring device 1. The resistance measuring device 1 measures the insulation resistance of the stator coil 20 using two electrodes 3 connected to the resistance measuring unit 2 via wiring 2a. More specifically, at the coil ends 21 of each of the two stator coils 20 connected by a joint pipe 30 inside the stator core 10, the tip portions 32 of the electrodes 3 of the resistance measuring device 1 are in contact with the conductors 22a of the stator coils 20.

[0025] As shown in Figure 4, the stator coil 20 includes a coil press-fit section 22 and an insulating section 23. The stator coil 20 is constructed by covering the outer circumference of a conductor 22a with a coating 23a. The coating 23a is made of an insulating material. In the coil press-fit section 22, the coating 23a is peeled off at both ends of the stator coil 20, exposing the conductor 22a. The tip of the coil press-fit section 22 is tapered to facilitate press-fitting into the joint pipe 30. The insulating section 23 is constructed such that the coating 23a, made of an insulating material, covers the outer circumference of the conductor 22a.

[0026] <Resistance measurement method> Figure 5 is a diagram illustrating a resistance measurement method according to one embodiment of the present invention. Resin is injected in advance into the hollow structure of the electrode 3 of the resistance measuring device 1 through the hole 31 of the electrode 3 (S101).

[0027] For example, the tip portion 32 of electrode 3 is used to cut through the coating 23a of the stator coil 20, exposing the conductor 22a (S102). Electrode 3 is brought into contact with the exposed conductor 22a to measure the insulation resistance of the stator coil 20 (S103). After measuring the insulation resistance, resin is injected, for example, from the tip portion 32 of electrode 3, to cover the exposed conductor 22a (S104).

[0028] Once the insulation resistance measurement of all stator coils 20 is complete (YES in S105), the measurement is complete. If there are any stator coils 20 whose insulation resistance has not been measured (NO in S105), the insulation resistance of the remaining stator coils 20 is measured.

[0029] When measuring the insulation resistance of the remaining stator coils 20, the process may begin with step S102, which involves exposing the conductors 22a of the stator coils 20. Alternatively, the process may begin with step S103, which involves measuring the insulation resistance, after exposing the conductors 22a of all stator coils 20 in advance.

[0030] These steps carry out a resistance measurement method according to one aspect of the present invention. However, the resistance measurement method according to one aspect of the present invention may include other steps as appropriate, depending on the measurement conditions, measurement environment, etc.

[0031] <Effects of the resistance measuring device 1 according to this embodiment> In the resistance measuring device 1 according to this embodiment, a hole is provided in the tip portion 32 of the electrode 3 to discharge resin from the inside of the hollow structure into the stator coil 20, and after measuring the insulation resistance of the stator coil 20, resin is injected into the portion of the conductor 22a of the stator coil 20 that is exposed. Since the injected resin has insulating properties, the insulation properties of the stator coil 20 can be restored. Therefore, according to the resistance measuring device 1 according to this embodiment, the decrease in insulation properties after measuring the insulation resistance of the stator coil 20 can be suppressed.

[0032] Furthermore, at least the surface of the electrode 3, including the pore 31, is treated to prevent resin from adhering. This makes it easy to remove any remaining resin from the electrode 3.

[0033] Therefore, according to the resistance measuring device 1 of this embodiment, after insulation resistance measurement, an insulation restoration process is performed immediately, thereby improving the efficiency of the insulation resistance measurement process and enhancing the reliability of the stator 100.

[0034] Although the present invention has been described above in accordance with the embodiments described above, the present invention is not limited to the configuration of the embodiments described above, and of course includes various modifications, alterations, and combinations that can be made by a person skilled in the art within the scope of the claims of the present patent application. [Explanation of Symbols]

[0035] 1. Resistance measuring device 2. Resistance Measurement Section 3 electrodes 4 probe 10 Stator Cores 20 Stator Coil 21 Coil End 22a Conductor 23a Coating 31 holes 32 Tip part 100 staters

Claims

1. A resistance measuring device for measuring the insulation resistance of a stator coil wound around a stator core which is a magnetic material, A resistance measuring unit for measuring the electrical resistance of the part to be measured, The resistance measuring unit is connected via wiring, and an electrode is provided to make contact with the conductor of the stator coil, Equipped with, The electrode has a hollow structure, and is provided with holes for injecting resin into the hollow structure and for discharging the resin from the hollow structure. Resistance measuring device.

2. The electrode is subjected to a surface treatment that prevents the resin from adhering to at least the holes in the electrode. The resistance measuring device according to claim 1.

3. The aforementioned surface treatment is a fluorine coating treatment. The resistance measuring device according to claim 2.

4. The aforementioned resin is either varnish or silicone sealant. The resistance measuring device according to claim 1.

5. A method for measuring insulation resistance using a resistance measuring device according to any one of claims 1 to 4, The process of cutting the coating of the stator coil to expose the conductor, A step of measuring the insulation resistance by bringing the electrode into contact with the exposed conductor, After measuring the insulation resistance, the process involves injecting the resin into the hole in the electrode at the location where the coating on the stator coil has been cut, A resistance measurement method including the following.

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