Insulation treatment method for stator for rotary electric machine, insulation treatment system for stator for rotary electric machine, and manufacturing method for rotary electric machine

Abstract

This insulation treatment method for applying varnish to a stator for a rotary electric machine with the stator being fixed to the inside of a stator frame comprises: a varnish injection step for injecting varnish to the inside of the stator frame; a varnish discharge step for discharging varnish from the inside of the stator frame; and a varnish drying step for, subsequent to the varnish discharge step, disposing a heater inside the stator, and drying varnish by heating from the inside of the stator frame. By using this method, varnish can be dried using simple equipment after a stator for a rotary electric machine is impregnated with varnish and has the same adhered thereto, and costs pertaining to the insulation treatment of the stator can be reduced.

Description

Insulation method for stator of rotating electric machine, insulation system for stator of rotating electric machine, and manufacturing method of rotating electric machine

[0001] The present disclosure relates to a method for insulating a stator of a rotating electric machine, a system for insulating a stator of a rotating electric machine, and a method for manufacturing a rotating electric machine.

[0002] Conventionally, when impregnating the stator core and stator windings of a rotating electric machine with varnish, a so-called vacuum impregnation method has been used in which the varnish is injected under reduced pressure to uniformly impregnate the stator windings to their depths.

[0003] For example, Patent Document 1 discloses a method in which both end openings of a stator frame are closed with detachable lids to form a sealed container, the inside of the sealed container is evacuated, and then varnish is poured into the container to impregnate the stator windings, and in which a cylindrical core whose outer diameter is smaller than the inner diameter of the stator core is used when carrying out this method.

[0004] Japanese Unexamined Patent Publication No. 62-23347

[0005] The method of Patent Document 1 does not require a vacuum tank for varnish impregnation, so varnish does not adhere to unnecessary areas such as the outer periphery of the stator frame, eliminating waste of varnish and the need for varnish removal. However, drying the varnish requires a large drying oven that can accommodate the rotating electric machine, and insulating the stator requires a large capital investment.

[0006] An object of the present disclosure is to impregnate and adhere varnish to a stator of a rotating electrical machine, and then dry the varnish using simple equipment.

[0007] The insulating treatment method for a stator of a rotating electric machine disclosed herein is an insulating treatment method in which varnish is applied to the stator of a rotating electric machine while the stator is fixed inside a stator frame, and includes a varnish injection step in which varnish is injected inside the stator frame, a varnish discharge step in which the varnish is discharged from inside the stator frame, and a varnish drying step in which a heater is placed inside the stator and the varnish is dried by heating from inside the stator frame after the varnish discharge step.

[0008] According to the present disclosure, after the stator of a rotating electrical machine is impregnated with and adhered to the varnish, the varnish can be dried using simple equipment, thereby reducing the cost associated with insulating the stator.

[0009] 1 is a diagram showing a rotating electric machine according to Example 1. FIG. 2 is a diagram showing only the stator frame and the stator of the rotating electric machine of FIG. 1. FIG. 3 is a diagram showing a sealed container configured for varnish impregnation according to Example 1. FIG. 4 is a diagram showing a configuration during varnish injection and varnish discharge according to Example 1. FIG. 5 is a diagram showing a state in which a core is attached to the upper lid of the sealed container of FIG. 3. FIG. 6 is a diagram showing a state in which a heater is inserted inside the stator frame according to Example 1. FIG. 7 is a flowchart showing a method for insulating a stator according to Example 1. FIG. 8 is a diagram showing a configuration during varnish discharge according to Example 2. FIG. 9 is a diagram showing a configuration for suctioning air from inside the stator frame during varnish drying according to Example 3. FIG. 10 is a flowchart showing a method for insulating a stator according to Example 4. FIG. 11 is a diagram showing a sealed container configured for varnish impregnation according to Example 5. FIG. 12 is a diagram showing a sealed container configured for varnish impregnation according to Example 6. FIG. 13 is a diagram showing the upper lid according to Example 6, viewed from the side where a packing is attached. FIG. 14 is a diagram showing the lower lid according to Example 6, viewed from the side where a packing is attached. FIG. 15 is a diagram showing a state in which a heater is attached to the upper lid according to Example 7. FIG. 16 is a diagram showing a sealed container configured such that a portion of the upper lid is detachable according to Example 8. Fig. 16 is a diagram showing a state in which a plug with a heater is attached instead of the plug 13d in Fig. 15. Fig. 17 is a flowchart showing a stator insulation method according to an eighth embodiment.

[0010] Hereinafter, examples of the present disclosure will be described with reference to the drawings. In principle, identical elements are assigned the same reference numerals in all drawings. Furthermore, descriptions of parts having the same functions will be omitted. Note that the configurations described below are merely examples, and it is not intended that the embodiments of the present disclosure be limited to the specific aspects below.

[0011] A first embodiment will be described with reference to FIGS. 1 to 7. FIG.

[0012] FIG. 1 is a diagram showing a rotating electric machine according to this embodiment. FIG. 2 is a diagram showing only the stator frame and stator of the rotating electric machine of FIG. 1. FIG. 3 is a diagram showing a sealed container configured for varnish impregnation according to this embodiment. FIG. 4 is a diagram showing the configuration when injecting and discharging varnish according to this embodiment. FIG. 5 is a diagram showing a state in which a core is attached to the upper lid of the sealed container of FIG. 3. FIG. 6 is a diagram showing a state in which a heater is inserted inside the stator frame according to this embodiment. FIG. 7 is a flowchart showing a stator insulation treatment method according to this embodiment.

[0013] The configuration of the rotating electrical machine will be described with reference to FIG.

[0014] In this figure, the rotating electric machine 100 comprises a stator frame 1, a stator 2, a rotor 3, a shaft 4, a bearing 5, a bearing 6, a bracket 7, a bracket 8, a fastener 9, a fastener 10, a stator core pressing plate 11, and a rotor core pressing plate 12.

[0015] The stator frame 1 houses and fixes the stator 2 inside. Removable brackets 7 and 8 are fastened to both axial ends of the stator frame 1 by fasteners 9 and 10. The stator frame 1 is usually cylindrical, but its outer shape may be a square pillar or other polygonal shape.

[0016] The stator 2 is composed of a stator core and a coil (stator winding). In this embodiment, the stator core is formed of laminated electromagnetic steel sheets. The laminated electromagnetic steel sheets are fixed in the axial direction by a stator core holder plate 11.

[0017] The rotor 3 is, for example, a squirrel-cage rotor made up of laminated electromagnetic steel sheets, secondary conductors, and short-circuit rings. The electromagnetic steel sheets are fixed in the axial direction by a rotor core retainer plate 12. Note that the effects of the present disclosure are not limited by the configuration of the rotor 3.

[0018] The shaft 4 is supported by a bearing 5 and a bearing 6. The bearing 5 is supported by a bracket 7, and the bearing 6 is supported by a bracket 8.

[0019] Fastener 9 fastens bracket 7 to stator frame 1, and fastener 10 fastens bracket 8 to stator frame 1. For convenience of illustration, one fastener 9 and one fastener 10 are shown, but it is usually desirable to use multiple fasteners.

[0020] Brackets 7 and 8 are detachable from stator frame 1. Therefore, bearings 5 ​​and 6 supported by brackets 7 and 8, as well as shaft 4 supported by bearings 5 ​​and 6, can also be removed from stator frame 1.

[0021] This allows components other than the stator frame 1 and the stator 2 to be removed as shown in FIG.

[0022] Next, a sealed container configured when insulating the stator frame 1 and the stator 2 will be described with reference to FIG.

[0023] The sealed container 200 shown in this figure is composed of a stator frame 1, an upper lid 13, and a lower lid 14. As described above, the stator 2 is fixed inside the stator frame 1. That is, the brackets 7 and 8 have been removed from the sealed container 200, and instead the upper lid 13 and the lower lid 14 have been attached.

[0024] The upper cover 13 has a varnish injection port 13 a and a vacuum suction port 13 b , and is detachably attached to the stator frame 1 .

[0025] The lower cover 14 has a varnish discharge port 14 a and is detachably attached to the stator frame 1 .

[0026] An upper cover 13 and a lower cover 14 are attached to the stator frame 1 and sealed to form a sealed container 200 .

[0027] Next, varnish injection and varnish discharge in the stator insulation process will be described with reference to FIG.

[0028] First, varnish injection will be described.

[0029] First, the pump 15 is operated to draw a vacuum inside the sealed container 200 through the vacuum suction port 13b. After the inside of the sealed container 200 reaches a vacuum state, the valve of the injection-side varnish tank 16 is opened and varnish is injected into the sealed container 200 through the varnish injection port 13a. Here, the injection-side varnish tank 16 and the piping arranged between the injection-side varnish tank 16 and the varnish injection port 13a constitute a varnish injection section.

[0030] On the other hand, when discharging the varnish, the valve of the discharge-side varnish tank 17 is opened and the varnish is discharged into the discharge-side varnish tank 17 through the varnish discharge port 14a. Here, the discharge-side varnish tank 17 and the piping arranged between the discharge-side varnish tank 17 and the varnish discharge port 14a constitute a varnish discharge section.

[0031] 5, if the upper cover 13 is configured to include the core 18, the amount of varnish required for insulating the stator can be reduced compared to when the core is not included. The same effect can be obtained by providing the core 18 on the lower cover 14.

[0032] Next, the configuration for drying the varnish, which is a feature of the first embodiment, will be described with reference to FIG.

[0033] 6, a heater 19 is inserted into the stator frame 1 and heated by passing current through it. When the inside of the stator frame 1 is sufficiently dried by the heating by the heater 19, the drying step is completed.

[0034] Next, a flowchart showing the overall stator insulation method will be described.

[0035] 7, when the stator insulation process is started, a drying step (step S11) is first performed. This removes moisture absorbed by the coils of the stator 2, etc., and ensures that the effects of the varnish impregnation are fully achieved. It is desirable to perform the drying step (step S11) by drawing a vacuum using a vacuum pump or the like.

[0036] Next, a varnish injection step (step S12) is performed, and after the varnish injection step is completed, the varnish discharge step (step S13) is started when the coil of the stator 2 is sufficiently impregnated. After the varnish discharge step (step S13) is completed, a drying step (step S14) is performed to dry the varnish. When the drying step (step S14) is completed, the stator insulation process is completed. The drying step of step S11 is also called the "moisture drying step." The drying step of step S14 is also called the "varnish drying step."

[0037] As described above, in Example 1, the stator insulation process can be easily performed without using a large drying oven that can accommodate a rotating electric machine, thereby achieving the effect of reducing the cost associated with the stator insulation process.

[0038] Second Embodiment A second embodiment will be described with reference to Fig. 8. In this embodiment, differences from the first embodiment will be mainly described.

[0039] FIG. 8 is a diagram showing the configuration when discharging varnish according to the second embodiment.

[0040] In this figure, in the varnish discharge step (step S13) in Fig. 7, a pump 15 is provided between the varnish discharge port 14a and the discharge-side varnish tank 17. The pump 15 is used to create a negative pressure inside the stator frame 1, thereby discharging the varnish. In other words, the discharge of the varnish is promoted in the varnish discharge step without using additional equipment such as a pressure pump.

[0041] Next, the effects of the second embodiment will be described.

[0042] In this embodiment, the inside of the stator frame 1 is kept under negative pressure, eliminating the risk of varnish escaping and allowing the surrounding area to be kept clean. Therefore, there is no need for additional equipment to inject pressurized gas, and no additional equipment installation space is required. Labor for transporting additional equipment is also reduced, and no cleaning labor is required, reducing labor costs. Furthermore, the pump 15 used for vacuuming can be reused to remove the varnish, eliminating the need for additional equipment.

[0043] As described above, according to the second embodiment, the effect of further reducing costs is achieved.

[0044] Third Embodiment A third embodiment will be described with reference to Fig. 9. In this embodiment, differences from the first and second embodiments will be mainly described.

[0045] FIG. 9 is a diagram showing a configuration for sucking air from inside the stator frame when the varnish is drying according to the third embodiment.

[0046] In this figure, in the drying step (varnish drying step) of step S14 in Fig. 7, air is sucked out of the stator frame 1 by the pump 15. In this case, since the top surface of the stator frame 1 is open, air flows in from the top surface and flows out from the bottom of the stator frame 1. Note that the position at which the pipe connected to the pump 15 is inserted into the stator frame 1 is merely an example, and the effect of the present disclosure is not limited to the insertion position.

[0047] Next, the effects of the third embodiment will be described.

[0048] Varnish typically contains volatile organic compounds, which can generate toxic gases when it dries. This can cause the toxic gas to fill the inside and surrounding area of ​​the stator frame 1, potentially endangering the safety of workers. In response to this issue, in Example 3, air is sucked out from inside the stator frame 1, preventing the toxic gas from filling the inside and surrounding area of ​​the stator frame 1 and improving work safety.

[0049] A fourth embodiment will be described with reference to Fig. 10. In this embodiment, differences from the first to third embodiments will be mainly described.

[0050] FIG. 10 is a flowchart showing a stator insulating method according to the fourth embodiment.

[0051] This figure differs from FIG. 7 (Example 1) in that a cleaning step (step S10) is included before a drying step (step S11).

[0052] In the cleaning step (step S10), the inside of the stator frame 1 is cleaned to remove dust adhering to the coils of the stator 2 and the like.

[0053] 10, a cleaning step is first performed (step S10). Thereafter, as in the first embodiment, a drying step (step S11), a varnish injection step (step S12), a varnish discharge step (step S13), and a drying step (step S14) are performed in this order, completing the stator insulation process.

[0054] Next, the effects of the fourth embodiment will be described.

[0055] The rotating electric machine 100 may be used in a dirty environment where dust is scattered, and dust may enter and adhere to the rotating electric machine 100 through a refrigerant intake port (not shown) or the like. If the stator is insulated while dust is attached, there is a concern that the effect of the varnish impregnation may not be fully achieved. In response to this issue, in Example 4, the inside of the stator frame 1 is cleaned to remove dust, so that the effect of the varnish impregnation can be fully achieved even for a rotating electric machine used in a dirty environment.

[0056] A fifth embodiment will be described with reference to Fig. 11. In this embodiment, differences from the first to fourth embodiments will be mainly described.

[0057] FIG. 11 is a diagram showing a sealed container configured for varnish impregnation according to Example 5.

[0058] In this figure, the difference from FIG. 3 (first embodiment) is that an upper cover 13 and a lower cover 14 are fixed by fasteners 9 and 10 that fasten brackets 7 and 8 (FIG. 1).

[0059] Next, the effects of the fifth embodiment will be described.

[0060] When attaching the upper cover 13 and the lower cover 14, fixing devices are required to prevent the covers from shifting, which increases the cost of insulating the stator. In response to this issue, in the fifth embodiment, the fasteners 9 and 10 that fasten the brackets 7 and 8 are reused, eliminating the need for additional fixing devices and achieving further cost reductions.

[0061] Sixth embodiment will be described with reference to Figures 12 and 13. In this embodiment, differences from the fifth embodiment will be mainly described.

[0062] Fig. 12 is a diagram showing a sealed container configured for varnish impregnation according to Example 6. Fig. 13A is a diagram showing the upper lid according to this Example as viewed from the side where the packing is attached. Fig. 13B is a diagram showing the lower lid according to this Example as viewed from the side where the packing is attached.

[0063] 12 , the packing 20 of the upper cover 13 and the packing 21 of the lower cover 14 are attached at positions where they come into contact with the stator frame 1. That is, the packing 20 is sandwiched between the upper cover 13 and the stator frame 1. In addition, the packing 21 is sandwiched between the lower cover 14 and the stator frame 1.

[0064] The configurations of the upper cover 13 and the lower cover 14 in this embodiment will be described in more detail with reference to FIGS. 13A and 13B.

[0065] 13A, the packing 20 is attached to the peripheral edge of the upper cover 13. The packing 20 has a fastener insertion opening 13c for inserting the fastener 9 therein.

[0066] As shown in FIG. 13B, the packing 21 is also attached to the peripheral edge of the lower cover 14 in a similar manner.

[0067] The number and positions of the fastener insertion openings 13c and the fastener insertion openings 14b are merely examples.

[0068] Next, the effects of the sixth embodiment will be described.

[0069] The stator frame and the lid are usually made of metal. This creates a small gap at the contact point between the stator frame and the lid, which can lead to varnish leakage and soiling of the surrounding area. To address this issue, in Example 6, the upper lid 13 and the lower lid 14 each have a gasket 20 and a gasket 21, respectively, which improves airtightness and prevents varnish leakage. This reduces labor costs associated with cleaning, further reducing costs.

[0070] Seventh Embodiment A seventh embodiment will be described with reference to Fig. 14. In this embodiment, differences from the first to sixth embodiments will be mainly described.

[0071] FIG. 14 is a diagram showing a state in which a heater is attached to the upper cover according to the seventh embodiment.

[0072] In this figure, the heater 19 is attached to the upper lid 13. However, the heater 19 may also be attached to the lower lid 14. That is, the heater 19 is fixed to at least one of the upper lid 13 and the lower lid 14. This makes it possible to heat the inside of the stator frame 1 with the lid attached. The heat from the heater 19 evaporates the water or solvent contained in the varnish inside the stator frame 1 and dissipates into the atmosphere via the varnish injection port 13a, the vacuum port 13b, etc. That is, the water drying step may be performed by heating with the heater 19.

[0073] Next, the effects of the seventh embodiment will be described.

[0074] When inserting the heater 19 into the stator frame 1, personnel or additional holders are required to hold the heater 19 so that it does not fall, which raises concerns about increased costs associated with insulating the stator. In response to this issue, in Example 7, the heater 19 is attached to the upper cover 13, eliminating the need for personnel or additional holders, and achieving the effect of further reducing costs associated with insulating the stator.

[0075] An eighth embodiment will be described with reference to Figures 15 to 17. In this embodiment, differences from the first to seventh embodiments will be mainly described.

[0076] Fig. 15 is a diagram showing a sealed container having a removable upper cover portion according to Example 8. Fig. 16 is a diagram showing a state in which a plug with a heater is attached instead of the plug 13d shown in Fig. 15. Fig. 17 is a flowchart showing a stator insulation method according to this example.

[0077] In FIG. 15, a part of the upper cover 13 is formed of a detachable plug 13d.

[0078] In FIG. 16, a part of the upper cover 13 is configured as a detachable plug 13e with a heater.

[0079] 15, the removable plug 13d is fixed to the upper cover 13 by a fastener. By removing the fastener, the removable plug 13d can be removed from the upper cover 13. The removable plug 13d may be configured to include a core, which can reduce the amount of varnish required for insulating the stator compared to when no core is included.

[0080] As shown in FIG. 16, the detachable heater plug 13e is also fixed to the upper cover 13 by the same fastener as the detachable plug 13d, and is configured to be attached to the location where the detachable plug 13d was removed.

[0081] That is, the heater 19 is fixed to a plug 13e that is detachable from the upper lid 13 (or the lower lid 14). The plug 13e is replaceable with another detachable plug 13d that does not have a heater.

[0082] Next, the insulating method for the stator of this embodiment will be described with reference to FIG.

[0083] First, a drying step (step S71) is performed. At this time, a detachable heater plug 13e is fixed to the upper lid 13 as shown in FIG. 16. That is, the drying step of step S71 is a moisture drying step. Next, a part replacement step (step S72), which is a feature of this embodiment, is performed. In the part replacement step (step S72), the detachable heater plug 13e is removed and a detachable plug 13d is attached. After this, a varnish injection step (step S73) and a varnish discharge step (step S74) are performed in order.

[0084] Next, a part replacement step (step S75), which is a feature of the eighth embodiment, is performed. In the part replacement step (step S75), the detachable plug 13d is removed and a detachable heater-equipped plug 13e is installed. Next, a drying step (step S76) is performed to dry the varnish. That is, the drying step of step S76 is a varnish drying step. When step S76 is completed, the stator insulation process is completed.

[0085] That is, in the part replacement steps of steps S72 and S75, the detachable heater-equipped plug 13e is replaced with another plug 13d.

[0086] Next, the effects of the eighth embodiment will be described.

[0087] 14 of Example 7, in the case where the heater 19 is directly attached to the upper lid 13, in order to prevent varnish from adhering to the heater 19 and causing a malfunction, it is necessary to exchange the upper lid 13 to which the heater 19 is directly attached with the upper lid (not shown) at the timing of transition from the drying step to the varnish injection step. In addition, it is also necessary to exchange the upper lid (not shown) with the upper lid 13 to which the heater 19 is directly attached at the timing of transition from the varnish discharge step to the drying step. In this way, the lid itself needs to be replaced.

[0088] In contrast, in Example 8, only a portion of the lid is replaced, which has the effect of reducing the number of steps required for insulating the stator compared to replacing the lid itself.

[0089] The stator insulating method of the eighth embodiment is based on the stator insulating method of the first embodiment, but may also be based on the stator insulating method of the fourth embodiment.

[0090] Next, a rotating electric machine manufactured using the stator insulation treatment method including the step of drying the varnish by disposing a heater inside the stator and drying the inside of the stator frame as in the above embodiment will be described, namely, a manufacturing method of the rotating electric machine and the completed rotating electric machine.

[0091] In addition, when a used rotating electric machine whose stator insulation film has deteriorated due to use is restored to a state similar to new, this also includes a case where a rotating electric machine whose useful life has expired and whose insulation film has deteriorated to the point where it is difficult to use normally is restored to a usable state again. In this case, since the useful life has expired, it is considered to be the reproduction of a rotating electric machine, which is a new product. Therefore, the insulation treatment method according to the present disclosure can also be applied when manufacturing a new rotating electric machine. The insulation treatment method according to the present disclosure may also be applied to a used stator even before the useful life has expired.

[0092] 1: stator frame, 2: stator, 3: rotor, 4: shaft, 5, 6: bearing, 7, 8: bracket, 9, 10: fastener, 11: stator core retainer plate, 12: rotor core retainer plate, 13: upper lid, 13a: varnish injection port, 13b: vacuum port, 13c, 14b: fastener insertion port, 13d, 13e: plug, 14: lower lid, 14a: varnish discharge port, 15: pump, 16: varnish injection tank, 17: varnish discharge tank, 18: core, 19: heater, 20, 21: packing, 100: rotating electric machine, 200: sealed container.

Claims

1. An insulation treatment method for applying varnish to a stator of a rotating electric machine while the stator is fixed inside a stator frame, the method comprising: a varnish injection step for injecting the varnish into the inside of the stator frame; a varnish discharge step for discharging the varnish from the inside of the stator frame; and a varnish drying step for, after the varnish discharge step, arranging a heater inside the stator and heating the stator frame from the inside to dry the varnish.

2. The insulation method of claim 1, further comprising a moisture drying step of drying the inside of the stator frame prior to the varnish injecting step.

3. The insulation treatment method according to claim 1, wherein the varnish injection step is performed by placing a core inside the stator.

4. The insulation treatment method according to claim 1, wherein the varnish removal step is performed by creating a negative pressure inside the stator frame.

5. The insulation treatment method according to claim 1, wherein the varnish drying step is performed by sucking air from inside the stator frame.

6. The insulation method of claim 2, further comprising a cleaning step of cleaning the inside of the stator frame before the moisture drying step.

7. The insulation treatment method according to claim 2, wherein the varnish injection step is carried out after both ends of the stator frame are sealed with lids and a vacuum is drawn using a pump, and the lids are fixed to the stator frame with the same fasteners as the brackets on the stator frame.

8. The insulation method according to claim 7, wherein a packing is sandwiched between the cover and the stator frame.

9. The insulation treatment method according to claim 7, wherein the heater is fixed to at least one of the lids.

10. The insulation treatment method according to claim 9, wherein the heater is fixed to a plug that is detachable from the lid, and the plug is configured to be replaceable with another detachable plug that does not have the heater.

11. The insulation treatment method according to claim 10, further comprising a part replacement step of replacing the plug with the other plug before the varnish injection step and after the varnish discharge step.

12. An insulation treatment system for applying varnish to a stator of a rotating electric machine while the stator is fixed inside a stator frame, the insulation treatment system comprising: a varnish injection unit that injects the varnish into the inside of the stator frame; a varnish discharge unit that discharges the varnish from the inside of the stator frame; and a heater that is placed inside the stator.

13. A method for manufacturing a rotating electric machine, comprising an insulating treatment step of applying varnish to a stator of a rotating electric machine while the stator is fixed inside a stator frame, the insulating treatment step comprising: a varnish injection step of injecting the varnish into the inside of the stator frame; a varnish discharge step of discharging the varnish from the inside of the stator frame; and a varnish drying step of, after the varnish discharge step, arranging a heater inside the stator and heating the stator frame from the inside to dry the varnish.

Images