JP7213424B2 - STATOR INSPECTION METHOD AND INSPECTION SYSTEM - Google Patents

Description

The present invention relates to a stator inspection method and inspection system.

A stator that constitutes a motor or the like has a coil, and the coil is made of an insulated wire. A specific example of the insulated wire is an enameled wire in which a copper wire as a conducting wire is coated with an insulating layer made of enamel. If there is an invisible defect such as a pinhole or a flaw in the insulation layer of the insulation-coated conductor, the coil will be short-circuited in an electrically conductive atmosphere, and the original function of the motor will be impaired.

Patent Literature 1 discloses a decompression heating bath that can be used for inspection of such stators. When inspecting the quality of the stator using this decompression heating bath, first, an inspection container having an inspection chamber is prepared, and an electrically conductive inspection liquid is supplied into the inspection chamber. Then, the stator is housed in the inspection chamber and immersed in the inspection liquid. After that, the pressure inside the inspection chamber is reduced, and the air existing inside the stator including the coil is removed as air bubbles. Then, by measuring the insulation resistance value and the amount of leakage current, leakage from the stator through the inspection liquid is inspected.

Japanese Utility Model Laid-Open No. 60-15658

However, according to the inventors' confirmation, the above-described conventional inspection method has a low accuracy in inspecting the quality of the stator, requires a long period of time for inspection, and is difficult to keep the inspection time constant.

That is, in this inspection method, since the pressure in the inspection chamber is reduced after the stator is immersed in the inspection liquid, the components of the inspection liquid tend to volatilize together with the air bubbles. For this reason, the electrical conductivity of the test liquid changes for each test, and the reference insulation resistance value and leakage current amount tend to change, so high test accuracy cannot be ensured.

In addition, in this inspection method, since the pressure in the inspection chamber is reduced after the stator is immersed in the inspection liquid, it is difficult for air to move from the inspection liquid that has permeated the inside of the stator, and it takes a long time to achieve a predetermined degree of vacuum. requires. In addition, since the amount of air contained in the test liquid may vary, the test time tends to vary.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stator inspection method and inspection system capable of inspecting the quality of a stator with high accuracy in a short and stable period of time. It is an issue that should be addressed.

A stator inspection method of the present invention is a method for inspecting a stator having a coil made of an insulated conductor,
a housing step of housing the stator in an inspection chamber in a sealed state;
After the housing step, a depressurization step of depressurizing the inspection chamber;
an immersion step of supplying a test liquid having electrical conductivity into the test chamber after the depressurization step, and immersing the stator in the test liquid ;
After the immersion step, an inspection step of inspecting electric leakage from the stator via the inspection liquid is provided.

In the inspection method of the present invention, since the storage process, decompression process, immersion process, and inspection process are executed in this order, the components of the inspection solution do not volatilize during the decompression process, and the electrical conductivity of the inspection solution changes for each inspection. hard. Therefore, the reference insulation resistance value and leakage current amount do not change, and high inspection accuracy can be ensured.

In addition, in this inspection method, since the immersion process is performed after the depressurization process of the inspection chamber containing the stator, the inspection liquid can be quickly penetrated into the inside of the stator including the coil simply by supplying the inspection liquid. can be done. Therefore, a predetermined degree of vacuum can be achieved in a shorter time than conventionally. Moreover, since the test solution is not subjected to the decompression process, the decompression time is stabilized.

Therefore, according to the stator inspection method of the present invention, the quality of the stator can be inspected with high accuracy in a short and stable period of time.

Further, the stator inspection system of the present invention is a stator inspection system having a coil made of an insulated conductor,
an inspection container formed therein with an inspection chamber capable of housing the stator in a sealed state and capable of immersing the stator in an electrically conductive inspection liquid;
a decompression device communicating with the examination room through a decompression passage and capable of decompressing the examination room;
a liquid tank communicating with the examination chamber through a liquid supply passage and storing the examination liquid;
a first on-off valve capable of opening and closing the pressure reducing passage;
a second on-off valve capable of opening and closing the liquid supply passage;
a control device that controls at least the first on-off valve and the second on-off valve;
an inspection device for inspecting electric leakage from the stator via the inspection liquid,
The control device closes the second on-off valve and opens the first on-off valve when there is no test liquid in the test chamber containing the stator,
When the inspection chamber reaches a predetermined degree of vacuum, the first on-off valve is closed and the second on-off valve is opened to supply the test solution into the inspection chamber,
The second on-off valve is closed and the inspection device is operated when the stator is immersed in the inspection liquid in the inspection chamber.

In the inspection system of the present invention, the control device closes the second on-off valve and opens the first on-off valve when there is no test liquid in the inspection chamber containing the stator. Therefore, the test liquid is not supplied from the liquid tank to the examination room, and the pressure in the examination room is reduced by the decompression device. Therefore, the components of the test liquid do not volatilize due to the decompression device. In addition, since the test liquid is not decompressed, a predetermined degree of vacuum can be achieved in a shorter and more stable period of time than in the conventional case.

Then, the control device closes the first on-off valve and opens the second on-off valve when the examination room reaches a predetermined degree of vacuum. Therefore, the examination room is maintained at a predetermined degree of vacuum, and the examination liquid is supplied from the liquid tank to the examination room. For this reason, the test liquid immerses the stator, and the test liquid quickly penetrates into the inside of the stator including the coil.

Next, the control device closes the second on-off valve and operates the inspection device when the stator is immersed in the inspection liquid in the inspection chamber. Therefore, the supply of the test liquid to the test chamber is stopped, and the electric leakage through the test liquid from the stator is tested. At this time, since the electrical conductivity of the test liquid is unlikely to change for each test, the reference insulation resistance value and leakage current amount do not change, and high test accuracy can be ensured.

Therefore, according to the stator inspection system of the present invention, the quality of the stator can be inspected with high accuracy in a short and stable period of time.

In the stator inspection method of the present invention, it is preferable to perform an atmosphere release step of opening the inspection chamber to the atmosphere between the immersion step and the inspection step.

The stator inspection system of the present invention preferably includes an atmosphere release valve capable of opening the inspection chamber to the atmosphere. Then, when the stator is immersed in the test liquid in the inspection chamber, the control device preferably closes the second on-off valve and then opens the inspection chamber to the atmosphere by the atmosphere release valve to operate the inspection device.

In this case, a small amount of air bubbles contained in the test liquid under reduced pressure can be eliminated from the test liquid by applying atmospheric pressure to the test liquid, so that higher inspection accuracy can be ensured than when the inspection process is performed under reduced pressure. .

According to the stator inspection method and inspection system of the present invention, the quality of the stator can be inspected with high accuracy in a short and stable period of time.

FIG. 1 is a process chart according to the inspection method and inspection system of the embodiment. FIG. 2 shows the inspection system of the embodiment, and is a schematic cross-sectional view during the storage process. FIG. 3 relates to the inspection system of the embodiment, and is a cross-sectional view of the motor housing and the like. FIG. 4 relates to the inspection system of the embodiment, and is a partially enlarged cross-sectional view of a cluster block and the like. FIG. 5 is a schematic diagram showing a stator and an inspection device. FIG. 6 shows the inspection system of the embodiment, and is a schematic cross-sectional view during the decompression process. FIG. 7 shows the inspection system of the embodiment, and is a schematic cross-sectional view during an immersion process, an atmospheric release process, and an inspection process.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the embodiment, quality of a stator 1 (see FIGS. 1, 3, 6 and 7) employed in a motor portion of an electric compressor for a vehicle is inspected.

In the inspection method of the embodiment, as shown in FIG. 1, a storage step S1, a decompression step S2, an immersion step S3, an atmosphere release step S4 and an inspection step S5 are performed. At this time, the inspection system of the embodiment is used. This inspection system includes an inspection container 3 , a vacuum pump 5 , a liquid tank 7 , a first on-off valve 9 , a second on-off valve 16 , a control device 13 and an inspection device 15 .

The inspection container 3, as shown in FIGS. 2 and 3, comprises a motor housing 3a and a lid 3b. The motor housing 3a forms part of the outer shell of the vehicle electric compressor. The motor housing 3a has an upper opening 3d and has a bottomed cylindrical shape. The stator 1 is fixed in the motor chamber 3c of the motor housing 3a by shrink fitting. A suction port 3e is formed at the lower end of the side wall of the motor housing 3a to communicate the outside with the motor chamber 3c. The motor room 3c is the inspection room of the present invention.

The lid 3b is made of resin. The lid 3b can be fitted into the opening 3d of the motor housing 3a from above to close the opening 3d and seal the motor chamber 3c. The stator 1 can be immersed in the motor chamber 3 c by being supplied with the test liquid 17 shown in FIG. 2 from the liquid tank 7 . As the test liquid 17, water adjusted to have a constant electrical conductivity, a mixed liquid of a fluorine-based inert liquid and a conductive liquid, a saline solution, or the like can be used.

The lid 3b is provided with a liquid supply passage 8b, a decompression passage 19b, and an air opening passage 20 communicating with the motor chamber 3c. The liquid supply passage 8 b is connected to the liquid supply passage 8 a connected to the liquid tank 7 , and the pressure reduction passage 19 b is connected to the pressure reduction passage 19 a connected to the vacuum pump 5 . The atmosphere release passage 20 communicates the motor chamber 3c with the atmosphere, and an atmosphere release valve 21 is provided in the middle. Further, the cover 3b is provided with a pressure sensor 25 capable of detecting the pressure in the motor chamber 3c.

The stator 1, as shown in FIGS. 3 and 4, has coils 1a, cores 1b, cluster blocks 1c, tubes 1d, terminals 1e, and sealing members 1f and 1g.

The coil 1a is made of an enameled wire in which an insulating layer made of enamel is coated on a copper wire. The core 1b has a plurality of slots, and each slot is provided with a coil 1a. The cluster block 1c is held within the motor housing 3a. The cluster block 1c is made of resin and has three passages inside.

As shown in FIG. 4, three pairs of leads 1i made of enameled wires extending from the coil 1a are inserted into a resin tube 1d before the cluster block 1c. Each tube 1d is held by a terminal 1e in each passage of the cluster block 1c, and the copper wire of the lead 1i in each tube 1d is electrically connected to the terminal 1e.

A current-carrying pin 29 is inserted through each terminal 1e. Each energizing pin 29 is to be connected to an inverter for driving the electric compressor outside the motor housing 3a.

The space between the sealing member 1f and the cluster block 1c is sealed with a resin sealant. Thus, in this stator 1, only the gap between the tube 1d and the lead 1i serves as a pressure equalizing passage. The sealing member 1g is fitted into the through hole 3f of the motor housing 3a through which the three energizing pins 29 are inserted, so that each energizing pin 29 can be sealed.

As shown in FIG. 2, the test container 3 is communicated with the filtering device 12 by a first recovery passage 10a communicating with the suction port 3e of the motor housing 3a. The filtering device 12 communicates with the liquid tank 7 via the second recovery path 10b. A liquid feed pump (not shown) is provided in the first recovery path 10a and the second recovery path 10b.

The liquid tank 7 stores the test liquid 17 recovered from the motor chamber 3c of the test container 3 in a vacuum state. A heater 7 a for adjusting the temperature of the test liquid 17 is provided in the liquid tank 7 . The liquid supply passages 8a and 8b communicate the bottom of the liquid tank 7 and the motor chamber 3c. A second on-off valve 16 is provided in the liquid supply passage 8a.

The first recovery path 10a is provided with an electromagnetic opening/closing device 14 that can open the suction port 3e to allow communication between the motor chamber 3c and the inside of the first recovery channel 10a, and can close the suction port 3e to seal the motor chamber 3c. there is

The test system of the embodiment also comprises a vacuum pump 5 connected to each test container 3 by vacuum passages 19a, 19b. A first on-off valve 9 is provided in the pressure reducing passage 19a. The vacuum pump 5 corresponds to a decompression device as a transformation device, and the decompression passages 19a and 19b correspond to the transformation passages. The vacuum pump 5 can depressurize the motor chamber 3c to a predetermined degree of vacuum or higher if the first on-off valve 9 is open.

5, the inspection device 15 is electrically connected to a connection terminal 27 connected to the motor housing 3a and a connection terminal 31 connected to a current-carrying pin 29 connected to the stator 1. As shown in FIG. The coil 1a consists of three phases and is Y-connected. Therefore, the connection terminal 31 is electrically connected to one terminal 1e in the cluster block 1c, as shown in FIG. The inspection device 15, as shown in FIG. 5, has a resistance meter 15a and a correction circuit 15b.

The correction circuit 15b is provided between the connection point P1 on the ohmmeter 15a side and the connection point P2 on the connection terminal 27 side. A conductor L1 having a resistance R1 is connected to the connection point P1. Conductors L2 to L4 are connected in parallel to the conductor L1 on the connection point P2 side of the resistor R1. A resistor R2 is provided on the conductor L2. The conducting wire L3 is provided with a capacitor C1 located on the side of the resistor R1 and a resistor R3 located on the side of the connection point P2. A capacitor C2 is provided on the conductor L4. This correction circuit 15b equalizes the change characteristics of the absorption current flowing between the ohmmeter 15a and the connection terminal 27 between the time and the insulation resistance value. The ohmmeter 15a detects an insulation resistance value between the connection terminal 31 and the correction circuit 15b, and inspects leakage from the stator 1 through the inspection liquid 17. FIG.

The inspection system also comprises a controller 13 . The control device 13 is electrically connected to the vacuum pump 5 and the inspection device 15 . Also, the motor housing 3a is placed on the weight scale 33. As shown in FIG. The control device 13 is also electrically connected to the weight scale 33 and the pressure sensor 25 . In addition, the first and second on-off valves 9 and 16, the air release valve 21, and the electromagnetic opening/closing device 14 are also electrically connected to the control device 13. A control device 13 controls these.

The quality of the stator 1 is inspected by this inspection system. First, as shown in FIGS. 1 and 2, as a storage step S1, the stator 1 is stored in the motor chamber 3c as an inspection room. At this time, as shown in FIG. 3, the stator 1 is already fixed in the motor chamber 3c of the motor housing 3a. As shown in FIG. 4, three current-carrying pins 29 provided on the cluster block 1c protrude outside the motor housing 3a through a through hole 3f and a sealing member 1g formed in the motor housing 3a. A connection terminal 31 is connected to one of the three conducting pins 29 .

After that, as shown in FIG. 6, the lid 3b is closed. At this time, the control device 13 closes the first on-off valve 9 and the second on-off valve 16 while the test liquid 17 is not in the motor chamber 3c. Further, the control device 13 operates the electromagnetic opening/closing device 14 to close the suction port 3e.

Next, as shown in FIGS. 1 and 6, the control device 13 operates the vacuum pump 5 and opens the first on-off valve 9 as a decompression step S2. Therefore, the test liquid 17 is not supplied from the liquid tank 7 to the motor chamber 3c, and the vacuum pump 5 decompresses the motor chamber 3c. Therefore, the components of the test liquid 17 are not volatilized by the vacuum pump 5 . In addition, since the test liquid 17 is not decompressed, a predetermined degree of vacuum can be achieved in a shorter and more stable time than in the conventional case.

The control device 13 determines whether or not the motor chamber 3c has reached a predetermined degree of vacuum based on the signal from the pressure sensor 25. When the motor chamber 3c reaches a predetermined degree of vacuum, the control unit 13 performs the operation as shown in FIGS. , the immersion step S3 is performed. At this time, first, the controller 13 closes the first on-off valve 9 and stops the operation of the vacuum pump 5 . Therefore, the motor chamber 3c is maintained at a predetermined degree of vacuum.

After that, the control device 13 opens the second on-off valve 16 . Therefore, the test liquid 17 is supplied from the liquid tank 7 to the motor chamber 3c. Therefore, the test liquid 17 begins to immerse the stator 1 . At this time, since the liquid supply passages 8a and 8b are provided in the lid 3b provided in the motor housing 3a, the test liquid 17 in the liquid tank 7 can be easily supplied to the motor chamber 3c. Further, the heater 7a heats the test liquid 17 in the liquid tank 7 in advance. Therefore, in the motor chamber 3c, the temperature of the motor housing 3a in which the stator 1 is shrink-fitted and the temperature of the test liquid 17 are quickly equalized, and variations in the insulation resistance value are quickly eliminated.

Next, the control device 13 determines whether or not the stator 1 is immersed in the test liquid 17 based on the signal from the weighing scale 33. If the test liquid 17 is supplied in an amount sufficient to immerse the stator 1, the second on-off valve is opened. Close 16. Therefore, the supply of the test liquid 17 to the motor chamber 3c is stopped. Thus, the test liquid 17 is managed in a vacuum state.

As shown in FIG. 1, after the immersion step S3, the controller 13 opens the atmosphere release valve 21 to perform an atmosphere release step S4 in which the inside of the motor chamber 3c is exposed to the atmosphere. At this time, a small number of air bubbles contained in the test liquid 17 are removed from the test liquid 17 under reduced pressure by applying atmospheric pressure to the test liquid 17 .

After the atmospheric release step S4, the controller 13 first measures the electric conductivity of the test liquid 17 in the motor chamber 3c. If the electrical conductivity is within a certain range, the inspection device 15 is operated to perform the inspection step S5. Specifically, the insulation resistance value is detected by the ohmmeter 15a, and leakage from the stator 1 through the test liquid 17 is inspected.

In this manner, in this inspection method and inspection system, since the storing step S1, the depressurization step S2, the immersion step S3, the atmospheric release step S4, and the inspection step S5 are executed in this order, volatilization of the components of the inspection liquid 17 during the depressurization step S2 is prevented. Therefore, the electrical conductivity of the test liquid 17 is less likely to change for each test. Therefore, the reference insulation resistance value does not change, and high inspection accuracy can be ensured.

Further, in this inspection method and inspection system, since the immersion step S3 is performed after the depressurization step S2 of the motor chamber 3c containing the stator 1 is performed, the stator 1 including the coil 1a can be inspected only by supplying the inspection liquid 17. The test liquid 17 can be quickly permeated to the inside. Therefore, a predetermined degree of vacuum can be achieved in a shorter time than conventionally. Moreover, since the test liquid 17 is not subjected to the decompression step S2, the decompression time is stabilized.

Furthermore, in this inspection method and inspection system, since the atmosphere release step S4 is performed between the immersion step S3 and the inspection step S5, even a small amount of air bubbles contained in the inspection liquid 17 is eliminated under reduced pressure, and high inspection accuracy is achieved. can be ensured.

Therefore, according to this inspection method and inspection system, the quality of the stator 1 can be inspected with high accuracy in a short and stable period of time.

Further, in this embodiment, the motor housing 3a to which the stator 1 is fixed is used as a part of the inspection container 3, so that the vehicle electric compressor can be assembled quickly after the inspection.

Although the present invention has been described above with reference to the embodiments, it goes without saying that the present invention is not limited to the above embodiments, and can be modified and applied without departing from the scope of the invention.

For example, in the embodiments, the quality of the stator 1 used in the motor portion of the electric compressor for a vehicle was inspected. Inspection is also possible. Also, the stator may not have the cluster block 1c or the like, and may not have a core or a housing.

Furthermore, instead of using the motor housing 3a as the inspection container, the stator may be stored in a separate inspection container for inspection.

A liquid feed pump may be provided between the liquid tank 7 and the test container 3 . The inspection device 15 can also inspect the quality of the stator 1 by detecting the amount of leakage current between the connection terminals 27 and the current-carrying pins 29 . It is also possible to employ other temperature control means for temperature control of the test solution instead of the heater 7a.

INDUSTRIAL APPLICABILITY The present invention can be used for production equipment such as motors.

DESCRIPTION OF SYMBOLS 1a... Coil 1... Stator 3... Inspection container 3c... Inspection room (motor room)
S1... Storage process S2... Decompression process 17... Inspection liquid S3... Immersion process S4... Atmospheric release process S5... Inspection process 19a, 19b... Decompression passage 5... Decompression device (vacuum pump)
8a, 8b... Liquid supply passage 7... Liquid tank 9... First on-off valve 16... Second on-off valve 13... Control device 15... Inspection device 21... Atmospheric release valve

Claims (4)

A method for inspecting a stator having coils made of insulated conductors, comprising:
a housing step of housing the stator in an inspection chamber in a sealed state;
After the housing step, a depressurization step of depressurizing the inspection chamber;
an immersion step of supplying a test liquid having electrical conductivity into the test chamber after the depressurization step, and immersing the stator in the test liquid ;
and an inspection step of inspecting electric leakage from the stator through the inspection liquid after the immersion step. 2. The method of inspecting a stator according to claim 1, wherein between said immersion step and said inspection step, an atmosphere opening step of opening said inspection chamber to the atmosphere is performed. An inspection system for a stator having coils made of insulated conductors,
an inspection container formed therein with an inspection chamber capable of housing the stator in a sealed state and capable of immersing the stator in an electrically conductive inspection liquid;
a decompression device that communicates with the examination room through a decompression passage and is capable of decompressing the examination room;
a liquid tank communicating with the examination chamber through a liquid supply passage and storing the examination liquid;
a first on-off valve capable of opening and closing the pressure reducing passage;
a second on-off valve capable of opening and closing the liquid supply passage;
a control device that controls at least the first on-off valve and the second on-off valve;
an inspection device for inspecting electric leakage from the stator via the inspection liquid,
The control device closes the second on-off valve and opens the first on-off valve when there is no test liquid in the test chamber containing the stator,
When the inspection chamber reaches a predetermined degree of vacuum, the first on-off valve is closed and the second on-off valve is opened to supply the test solution into the inspection chamber,
A stator inspection system, wherein the second on-off valve is closed and the inspection device is operated when the stator is immersed in the inspection liquid in the inspection chamber. Equipped with an air release valve capable of opening the inspection room to the atmosphere,
When the stator is immersed in the test solution in the inspection chamber, the control device closes the second on-off valve, and then opens the inspection chamber to the atmosphere by the atmosphere release valve to operate the inspection device. 4. The stator inspection system according to claim 3.

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