Resistance measurement device and resistance measurement method

Abstract

The present invention provides a resistance measuring device capable of suppressing a decrease in insulating properties after measuring the insulation resistance of a stator coil. This resistance measurement device measures the insulation resistance of a stator coil wound around a stator core, which is a magnetic body, and is provided with: a resistance measurement unit that measures the resistance of a site to be measured; and an electrode which is connected to the resistance measurement unit via a wiring and is used for bringing the electrode into contact with a conductor of the stator coil, the electrode having a hollow structure and being provided with a hole for injecting a resin into the hollow structure and discharging the resin from the inside of the hollow structure.

Description

Technical Field

[0001] This invention relates to a device and method for measuring the resistance of the stator of a rotating electric machine. Background Technology

[0002] A known technique involves using the electrodes at the tip of a probe to scratch the insulating coating of a stator coil assembly to measure the insulation resistance between the probe and the stator coil. Patent Document 1 discloses a technique where a knife-mark-like incision is cut into the insulating coating, an insulation resistance meter is connected between the coil's connector terminal and the stator core to measure the insulation resistance value, and the insulation performance is determined based on the measurement result.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2001-289921 Summary of the Invention

[0004] When stator coils are joined within an iron core, the joint cannot be observed with the naked eye. Therefore, the insulation resistance is measured by scratching the insulating coating at the end of the stator coil to ensure the insulation resistance of the joint. In the technology disclosed in Patent Document 1, the conductor is exposed due to the scratching of the insulating coating, which poses a risk of reduced insulation after the insulation resistance is measured.

[0005] The purpose of this invention is to provide a resistance measuring device that can suppress the decrease in insulation performance after measuring the insulation resistance of the stator coil.

[0006] The present invention relates to a resistance measuring device for measuring the insulation resistance of a stator coil wound on a stator core, which is a magnetic body. The resistance measuring device comprises: a resistance measuring part for measuring the resistance of the part to be measured; and an electrode connected to the resistance measuring part via wiring for contacting the conductor of the stator coil. The electrode has a hollow structure and is provided with a hole for injecting resin into the hollow structure and discharging the resin from the hollow structure.

[0007] Invention Effects

[0008] This invention provides a resistance measuring device that can suppress the decrease in insulation performance after measuring the insulation resistance of the stator coil. Attached Figure Description

[0009] Figure 1 This is a diagram showing the structure of a resistance measuring device according to an embodiment of the present invention.

[0010] Figure 2 This is a perspective view showing the structure of the stator according to one embodiment of the present invention.

[0011] Figure 3 yes Figure 2 The stator shown is a cross-sectional view along line III-III.

[0012] Figure 4 It is used for explanation Figure 2 The diagram shows the structure of the stator coil.

[0013] Figure 5 This is a diagram illustrating a resistance measurement method according to an embodiment of the present invention. Detailed Implementation

[0014] Hereinafter, embodiments will be described with reference to the accompanying drawings. However, since the drawings are simplified, the technical scope of the embodiments should not be narrowly interpreted based on the description in the drawings. Furthermore, the same symbols are used to denote the same elements, and repeated descriptions are omitted. Also, in the following embodiments, when referring to the quantity of elements (including number, value, quantity, range, etc.), the quantity is not limited to that specific quantity, except in particularly explicit cases or cases where it is clearly limited to a specific quantity in principle; it may be more than that specific quantity or less.

[0015] Furthermore, in the following embodiments, the constituent elements are not necessarily essential, except in cases where they are particularly explicit or where they are clearly considered essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of constituent elements, etc., this includes structures that are substantially similar to or analogous to their shape, except in cases where they are particularly explicit or where they are clearly not considered essential in principle. This also applies to the quantities, etc. (including number, value, quantity, range, etc.) mentioned above.

[0016] [Implementation Method]

[0017] <Structure of Resistance Measuring Device 1>

[0018] Figure 1 This diagram illustrates the structure of a resistance measuring apparatus 1 according to an embodiment of the present invention. The resistance measuring apparatus 1 includes 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 a wiring 2a. The resistance measuring unit 2 includes a control circuit 5, an indicator 6, and a DC voltage generating circuit 7, and is connected to a clip 8. The resistance measuring unit 2 measures the resistance of the area to be measured. In this embodiment, the resistance measuring apparatus 1 will be used later. Figure 2 The insulation resistance is measured by taking the conductor 22a of the stator coil 20, which will be described in detail, as the part to be measured.

[0019] Furthermore, a switch 9 is provided on the probe 4, configured such that the electrode 3, which extends from the front end of the probe 4, is protruded by a spring 3a. In the illustrated example, the switch 9 is located on the probe 4, but it could also be located in a component other than the probe 4.

[0020] When measuring insulation resistance, for example, the tip portion 32 of electrode 3 is used to puncture the film 23a of the stator coil 20, which is the object of insulation resistance measurement, 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.

[0021] Then, by pressing the front end portion 32 of electrode 3 onto the conductor 22a of stator coil 20, which is the object being measured, electrode 3 is retracted against spring 3a, and terminal 3b of electrode 3 is connected to terminal 9a of switch, transmitting information to control circuit 5. Furthermore, the insulation resistance of stator coil 20 is measured by displaying information on indicator 6 provided on resistance measuring unit 2.

[0022] In this embodiment, the electrode 3 has a hollow structure with holes 31 for injecting or discharging resin. In addition to the holes 31, another hole (not shown) is provided on the front end portion 32 of the electrode 3. Before measuring the insulation resistance, resin is injected into the hollow structure of the electrode 3. The resin inside the hollow structure is discharging from the holes in the front end portion 32 of the electrode 3. Furthermore, the discharging of the resin is not limited to the holes in the front end portion 32; it can also be discharging from the holes 31 on the side, etc. Moreover, the holes 31 are not limited to one; multiple holes can be provided.

[0023] Resin ejected from the front end portion 32 of electrode 3 is injected into stator coil 20 to cover the exposed conductor 22a. The resin can be, for example, insulating varnish or silicone sealant, but is not limited to these; any resin with insulating properties is acceptable. The resin injected into stator coil 20 contacts the exposed conductor 22a, restoring the insulation of stator coil 20. According to the resistance measuring apparatus 1 of this embodiment, resin can be injected directly from electrode 3 into stator coil 20 immediately after resistance measurement, thus immediately restoring the insulation of stator coil 20.

[0024] Furthermore, at least on the holes 31, a surface treatment to prevent resin adhesion is applied to the electrode 3. The surface treatment is, for example, a fluorine coating, but is not limited to this; any treatment capable of preventing resin adhesion is acceptable. Therefore, resin residue in the electrode 3 can be easily removed.

[0025] Furthermore, the resistance measuring device 1 described in this embodiment is not limited to... Figure 1 The structure shown can be adapted to various configurations.

[0026] <Structure of Stator 100>

[0027] Here, use Figures 2-4 The structure of the stator 100 will be described, which includes a stator coil 20 for measuring insulation resistance using the resistance measuring device 1 according to this embodiment. Figure 2 This is a perspective view showing the structure of the stator 100 according to an embodiment of the present invention. Figure 3 yes Figure 2 The stator 100 shown is a cross-sectional view along line III-III. Figure 4 It is used for explanation Figure 2 A diagram showing the structure of the stator coil 20.

[0028] like Figure 2 and Figure 3 As shown, in the stator 100 of this embodiment, two stator coils 20 are connected inside the stator core 10, which is a magnetic body, by means of a connector tube 30. The stator 100 configured in this way, when combined with a rotor (not shown), can be used, for example, as a rotary motor mounted in vehicles such as electric motors, generators, battery electric vehicles (BEVs), and hybrid electric vehicles (HEVs).

[0029] The rotary motor rotates around the rotating shaft C by the electromagnetic interaction between the rotating magnetic field and the rotor. The rotating magnetic field is generated by the current flowing in the stator coils 20 contained in the stator 100.

[0030] The direction of the rotation axis C will be explained below as the axial direction.

[0031] The stator core 10 can be constructed by stacking multiple generally cylindrical electromagnetic steel plates. Each electromagnetic steel plate has a substantially identical shape and can be formed separately by processes such as punching. The stator core 10 includes an annular yoke 11 extending circumferentially and multiple teeth 12 extending radially inward from the inner circumferential surface of the yoke 11. The multiple teeth 12 are spaced apart from each other in the circumferential direction, and slots are formed between adjacent teeth 12 in the circumferential direction.

[0032] The stator coil 20 may include a three-phase stator coil 20. The stator coil 20 is mounted on each tooth 12 via slots between the teeth 12. The coil ends 21 of the stator coil 20 pass through slots at different circumferential positions and extend out of the axial end face of the stator core 10, and the coil ends 21 are bent together in the circumferential direction.

[0033] like Figure 2As shown, the insulation resistance of the stator coil 20 is measured using a 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 a wiring 2a. More specifically, in the coil ends 21 of the two stator coils 20 connected by a connector tube 30 inside the stator core 10, the front end portion 32 of the electrode 3 of the resistance measuring device 1 contacts the conductor 22a of the stator coil 20.

[0034] like Figure 4 As shown, the stator coil 20 includes a coil pressing portion 22 and an insulating portion 23. The stator coil 20 is configured such that the outer periphery of the conductor 22a is covered by a coating 23a. The coating 23a is made of an insulating material.

[0035] The coil pressing portion 22 exposes the conductor 22a by peeling off the film 23a from both ends of the stator coil 20. The front end of the coil pressing portion 22 is tapered to facilitate pressing into the connector tube 30. Furthermore, the insulating portion 23 is configured such that the film 23a made of an insulating material covers the outer periphery of the conductor 22a.

[0036] <Methods for measuring resistance>

[0037] Figure 5 This is a diagram illustrating a resistance measurement method according to an embodiment of the present invention. Resin is injected into the hollow structure of the electrode 3 of the resistance measuring device 1 through the hole 31 of the electrode 3 beforehand (S101).

[0038] For example, the tip portion 32 of electrode 3 is used to cut through the film 23a of stator coil 20, exposing conductor 22a (S102). Electrode 3 is brought into contact with the exposed conductor 22a, and the insulation resistance of stator coil 20 is measured (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).

[0039] When the insulation resistance of all stator coils 20 has been measured (S105 "Yes"), the measurement is complete. If there are stator coils 20 whose insulation resistance has not been measured (S105 "No"), the insulation resistance of the remaining stator coils 20 is measured.

[0040] When measuring the insulation resistance of the remaining stator coils 20, the process can begin from step S102, which is the process of exposing the conductors 22a of the stator coils 20. Alternatively, the process can begin from step S103, which is the process of measuring the insulation resistance, after all the conductors 22a of the stator coils 20 have been exposed in advance.

[0041] These steps implement the 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 appropriately include other steps depending on the measurement conditions or measurement environment.

[0042] <Effects of the resistance measuring device 1 according to this embodiment>

[0043] In the resistance measuring apparatus 1 according to this embodiment, a hole is provided at the front end portion 32 of the electrode 3 for discharging resin from the interior of the hollow structure into the stator coil 20. After measuring the insulation resistance of the stator coil 20, resin is injected into the exposed portion of the conductor 22a of the stator coil 20. The injected resin has insulating properties, thus restoring the insulation of the stator coil 20. Therefore, according to the resistance measuring apparatus 1 according to this embodiment, the decrease in insulation after measuring the insulation resistance of the stator coil 20 can be suppressed.

[0044] Furthermore, a surface treatment to prevent resin adhesion is applied to at least the surface of the hole 31 containing the electrode 3. Therefore, it is possible to easily remove resin residue from the electrode 3.

[0045] Therefore, according to the resistance measuring device 1 of this embodiment, insulation recovery processing is performed immediately after the insulation resistance is measured, thereby improving the efficiency of the process related to the insulation resistance measurement and the reliability of the stator 100.

[0046] The present invention has been described above according to the above embodiments, but the present invention is not limited to the above embodiments. Various modifications, alterations and combinations that can be made by those skilled in the art within the scope of the claims of this application are naturally included within the scope of the present invention.

[0047] Symbol Explanation

[0048] 1-Resistance measuring device, 2-Resistance measuring part, 3-Electrode, 4-Probe, 10-Stator core, 20-Stator coil, 21-Coil end, 22a-Conductor, 23a-Sheet, 31-Hole, 32-Front end part, 100-Stator.

Claims

1. A resistance measuring device for measuring the insulation resistance of a stator coil wound on a stator core that is a magnetic body, characterized in that it comprises: A resistance measuring unit that measures the resistance of the part to be measured; and An electrode, connected to the resistance measuring unit via wiring, is used to bring the electrode into contact with the conductor of the stator coil. The electrode has a hollow structure and is provided with holes for injecting resin into the hollow structure and discharging resin from the hollow structure.

2. The resistance measuring device according to claim 1, characterized in that, In the electrode, at least the pores of the electrode are treated with a surface treatment to prevent the resin from adhering.

3. The resistance measuring device according to claim 2, characterized in that, The surface treatment is a fluorine coating treatment.

4. The resistance measuring device according to claim 1, characterized in that, The resin is either an insulating varnish or a silicone sealant.

5. A method for measuring resistance, comprising measuring insulation resistance using the resistance measuring device according to any one of claims 1 to 4, wherein the method for measuring resistance comprises: The process of piercing the liner of the stator coil to expose the conductor; The process of contacting the electrode with the exposed conductor to measure the insulation resistance; and The process of injecting resin into the perforated portion of the diaphragm on the stator coil after measuring the insulation resistance.

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