JP5454709B2 - Method for manufacturing stator coil of rotating electric machine - Google Patents

Description

  The present invention relates to a method of manufacturing a stator coil of a rotating electrical machine in which an insulating resin is vacuum-impregnated and impregnated with a stator coil of an unimpregnated rotating electrical machine placed in a slot of a stator core.

  There are two types of insulation methods for stator coils of rotating electrical machines such as generators and electric motors: a single coil insulation method and a fully impregnated insulation method. The former is a system in which a coil impregnated with an insulating resin in advance is placed in a slot of a stator core. The latter is a method of impregnating an insulating resin after an unimpregnated coil is placed in a slot of a stator core.

  Since the latter fully impregnated insulation method can reduce the manufacturing process compared to the former method, in a stator coil of a recent rotating electric machine, all of this, from a small induction motor to a large turbine generator. The impregnation insulation method is widely adopted.

  FIG. 6 shows a configuration of a conventional stator coil based on the all-impregnation insulation method disclosed in Patent Document 1.

  The stator coil 5 is formed by winding a ground insulating tape 54 such as a miker tape around a wire coil 53 formed by winding a plurality of wire conductors 51 to which a wire insulation 52 is applied. A main insulating layer 56 which is impregnated and becomes a ground insulating layer is formed, and a slot corona preventing layer 57 is wound around the outer periphery of the main insulating layer 56. Two coils 5 are accommodated in the slots 41 of the stator core 4 in a vertically parallel manner, and an interlayer insulating material 32 is disposed between the upper coil 5 and the lower coil 5. The upper and lower coils 5 are housed inside the slot 41, and the upper portion of the upper coil 5 is pressed by a wedge 35.

  In FIG. 6, the ground insulating tape 54 of the main insulating layer 56 is wound in a state not impregnated with resin. The slot corona prevention layer 57 on the surface of the coil 5 is a layer formed by winding a semiconductive tape. This semiconductive tape is composed of a semiconductive non-woven fabric, a semiconductive film, a semiconductive glass cloth, or the like. The corona prevention layer 57 prevents the generation of corona between the main insulating layer 56 and the slot 41. The interlayer insulating material 32 is a glass laminated plate impregnated with an epoxy resin, and maintains the interval between the upper and lower coils 56 at a predetermined insulating dimension. The wedge 35 is also composed of a glass laminate impregnated with an epoxy resin. The wedge 35 prevents the coil 5 from vibrating inside the slot 41 during operation.

FIG. 7 is a cross-sectional view showing the main configuration of the slot exit of the stator coil of FIG. This is a cross-sectional view taken along line XI-XI in FIG. When the coil 5 protrudes outward from the end face 42 in the axial direction of the iron core 4, an end corona prevention layer 58 is provided, and the main insulating layer 56 is covered following the surface corona prevention layer 57. Further, the insulating protective layer 59 covers the end corona preventing layer 58 and the surface corona preventing layer 57. The end corona prevention layer 58 is formed by winding a semiconductive tape containing SiC, and prevents the occurrence of creeping corona outside the coil 5 (outside the iron core 4). The insulating protective layer 59 is formed by winding a heat-shrinkable tape or film, or a tape obtained by bonding a heat-shrinkable tape and a film, in order to suppress swelling of the main insulating layer 52 and the end corona-preventing layer 58. And for preventing leakage of the resin after the resin impregnation.
The finger 45 protruding from the end face 42 of the stator core 4 is a member for pressing a tooth portion forming the slot 41 of the stator core 4.
In this way, when the stator coil 5 thus configured is subjected to insulation treatment by a single coil impregnation method, the non-uniform bulge of the unimpregnated coil is molded when set in the impregnation mold, and thereafter Since the insulating resin can be impregnated and cured to be manufactured to a predetermined size, a coil having a uniform dimension and having no uneven bulge can be inserted into the iron core.

However, if the stator coil is insulated by impregnation and hardening with insulating resin after the stator coil is placed in the stator core, an unimpregnated coil with non-uniform swelling is inserted into the core. For this reason, the coil end portion outside the iron core remains swollen.
In order to suppress such a bulge, an insulating protective layer is formed by a heat-shrinkable tape having a function of shrinking the coil end portion by heat at the time of impregnation and curing and suppressing the bulge.
Japanese Patent Laid-Open No. 10-17433

  However, when the insulating protective layer 59 is formed by winding a heat shrink tape or the like around the coil end portion exposed to the outside of the iron core of the stator coil 5 inserted in the stator core 4, the thickness of the insulating protective layer is as follows. As shown in FIG. 7, the coil 5 has a thick free space and the free space near the core end surface of the coil end portion is small because the core pressing finger 45 protrudes toward the end surface 42 side of the core 4. The insulating protective layer 59 can be provided only to a certain distance L from the iron core end face of the coil end portion. For this reason, there is a problem that not only the bulge B is likely to be generated in the vicinity of the end face 42 of the iron core 4, but also the bulge generated in this portion cannot be suppressed even if the impregnation and hardening of the insulating resin is performed.

  Such swelling of the insulating layer in the stator coil reduces the insulation performance and shortens the insulation life of the stator coil when used in a high voltage rotating electrical machine. .

  In order to solve the above-described problems, the present invention provides a stator coil for a rotating electrical machine that performs insulation treatment by a full impregnation method, in which the stator core of the coil end portion exposed to the outside of the stator core of the stator coil is exposed. It is an object of the present invention to provide a method for manufacturing a stator coil that can suppress the occurrence of swelling of an insulating layer up to the vicinity of an end face.

  In order to solve the above-described problems, the present invention impregnates an insulating resin in a state where a stator coil in which a main insulating layer is formed by winding a tape insulating material around the whole wire coil is mounted in a slot of the stator core. In a method of manufacturing a stator coil of a rotating electrical machine that is cured and insulated, a core pressing member that protrudes from an axial end surface of a stator core on which the stator coil is mounted and a stator that protrudes from the stator core After inserting a jig for pressing the vicinity of the axial end surface of the stator core of the stator coil between the coils, the resin was impregnated and hardened, and the jig was removed after this process was completed. It is characterized by this.

  In the manufacturing method described above, the jig can be improved in peelability from the impregnated and hardened insulating resin by constituting the surface with a fluororesin.

  In the above manufacturing method, the releasability from the impregnated and hardened insulating resin can be enhanced by inserting the jig through a release material.

  According to the manufacturing method of the present invention, after the unimpregnated stator coil is mounted on the stator core, the core pressing member protruding from the axial end surface of the stator core and the stator coil extending outside the stator core. By inserting a jig that presses the coil between the coil end portion and the vicinity of the short surface of the stator core, the swelling of the insulating layer generated in the coil end portion of the stator coil attached to the iron core was suppressed. Since the insulation resin is impregnated and cured in this state, the fixed coil that has been subjected to the insulation treatment can be a coil without swelling of the insulation layer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional view of a stator coil according to a first embodiment of the present invention, in which (a) shows a state before impregnation hardening treatment of insulating resin, and (b) shows impregnation hardening treatment of insulating resin. Shown later. BRIEF DESCRIPTION OF THE DRAWINGS It shows the structure of an example of a heat-shrinkable semiconductive tape that locks and controls the heat-shrinkable slot corona prevention layer used in the first embodiment of the present invention, (a) is a plan view, (b) is a plan view. It is a longitudinal cross-sectional view. FIG. 2 shows the structure of another example of a heat-shrinkable semiconductive tape that locks and controls the heat-shrinkable slot corona prevention layer used in the first embodiment of the present invention. FIG. ) Is a longitudinal sectional view. It is a partial cross section figure explaining the structure of Example 2 of the manufacturing method of this invention. It is a longitudinal cross-sectional view which shows the example of the jig for coil pressing used in Example 2 of this invention. It is a partial longitudinal cross-sectional view which shows the structure of the stator coil of the conventional rotary electric machine. It is a partial cross-sectional view which shows the structure of the stator coil of the conventional rotary electric machine.

  Embodiments of the present invention will be described with reference to the embodiments shown in the drawings.

  1 to 3 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing the configuration of a stator coil manufactured according to the present invention, and FIGS. 2 and 3 are configuration diagrams of a semiconductive tape used in the first embodiment.

  The stator coil 5 of FIG. 1 is provided with a main insulating layer 56 made of a miker tape or the like as a ground insulating layer on the outer periphery of the wire coil 53 as in the conventional example described above. A heat-shrinkable slot corona prevention layer 57a formed by winding a heat-conducting semiconductive tape is formed outside the main insulating layer 56 of the wire coil 53. The slot corona prevention layer 57a is originally provided only in a portion that fits in the slot 41 of the coil 5 when the coil 5 is mounted in the slot 41 of the stator core 4. It is formed to extend to the coil end portion of the wire coil 53 that protrudes to the outside. This slot corona prevention layer 57a is extended until it overlaps with a portion of the end corona prevention layer 58 provided in the bent portion of the wire coil in the coil end portion outside the iron core 4 in the conventional example shown in FIG.

  The coil end portion outside the core 4 of the wire coil 53 in which the main insulating layer 56, the heat-shrinkable slot corona prevention layer 57a, and the end corona prevention layer 58 are formed in this way is further similar to the conventional example. The coil protective layer 59 is formed by winding a heat-shrinkable insulating tape around the coil.

  When the coil 5 configured in this manner is mounted in the slot 41 of the stator core 4 without impregnating the insulating resin, the portion that fits in the slot of the coil is regulated by the inner wall of the slot 41. Then, the insulating layer does not swell. However, when the outside of the slot 41 comes out, the restriction is removed, and as shown in FIG. 1A, a bulge B of the insulating layer occurs particularly near the outlet of the slot 41 on the axial end surface of the iron core 4.

  When the impregnating and hardening treatment of the thermosetting insulating resin is performed by a well-known method with the coil 5 not impregnated with the insulating resin being attached to the iron core 4, the heat-shrinkable slot corona is heated by heating in this treatment process. The prevention layer 57a and the heat-shrinkable insulating protective layer 59 contract, and the wire coil 53 is compressed from the outside of the main insulating layer 56 to the whole. Thereby, the bulge B generated near the outlet of the slot 41 at the end of the iron core 4 of the main insulating layer 56 is crushed and disappears. Therefore, the stator coil 5 that has been subjected to the impregnation hardening treatment of the insulating resin becomes a coil that does not swell in the insulating layer, as shown in FIG.

  An example of the heat-shrinkable semiconductive tape used for the heat-shrinkable slot corona prevention layer 57a in the present invention is shown in FIG. 2 and FIG.

  The semiconductive tape CK shown in FIG. 2 is a semiconductive agent formed by a tape-like or sheet-like base material T composed of warp Tl composed of polyester fiber having high heat shrinkability and weft TP composed of glass fiber. It is constructed by carrying SC. The semiconductive tape configured as described above has a property of increasing thermal shrinkage in the longitudinal (length) direction of the base material T.

  The semiconductive tape CK shown in FIG. 3 is configured by using a polyester film having a large heat shrinkability as a base material F of the tape and supporting the semiconductive agent SC by the base material F. The semiconductive tape configured as described above has heat shrinkability in the longitudinal (length) direction and the lateral (width) direction of the tape.

  Next, Example 2 which shows the manufacturing method of this invention in FIG.4 and FIG.5 is demonstrated.

  In a state where the stator coil 5 not impregnated with the insulating resin is mounted on the fixed iron core 4, as shown in FIG. 1A, the stator coil 5 swells in the vicinity of the outlet from the slot 4 of the iron core of the insulating layer 53 of the coil 5. B has occurred. In the second embodiment, as shown in FIG. 4 in this state, a finger 45 as a core pressing member protruding from an end surface in the axial direction of the iron core and a wire coil 53 having a main insulating layer 56 are provided. By press-fitting the coil holding jig 7 in between, it is possible to press the vicinity of the exit of the core slot of the insulating layer of the coil, so that the bulge generated in this vicinity is crushed and flattened. it can.

  As shown in FIG. 5, the coil pressing jig 7 used here is a coating layer in which the surface of a main body 71 made of plywood or the like is formed of an insulating resin, for example, a fluororesin having almost no adhesive force with an epoxy resin. 72.

In this way, by inserting the coil holding jig 7 between the finger 45 and the coil 5 in the stator core 4 to which the stator coil 5 not impregnated with the insulating resin is mounted, the iron core of the insulating layer of the coil is inserted. In a state in which the bulge B generated in the vicinity of the end face is crushed and flattened, an impregnation hardening treatment with an insulating resin is performed by a known method. In the course of this treatment, the insulating resin is also deposited on the surface of the jig 7, but the surface of the jig 7 is covered with a surface layer 71 made of a fluororesin that has little adhesion to the insulating resin. Thus, the jig 7 is not bonded to the finger 45 and the coil 5 via the insulating resin. For this reason, the jig 7 can be easily pulled out from between the finger 45 and the coil 5 after the impregnation hardening treatment of the insulating resin. By pulling out the jig 7 and removing it from between the iron core (finger) and the coil 5, the insulation treatment of the stator coil 5 is completed.
The same effect can be obtained even if the coil pressing jig 7 is press-fitted through a release material such as fluororesin or silicon resin without providing the coating layer 72 on the coil pressing jig 7. be able to.

  According to the method of the second embodiment, before the stator coil 5 is attached to the stator core 4 and impregnated and hardened with the insulating resin, the gap between the finger 45 protruding from the end surface of the core and the stator coil 5 is reduced. Since the coil holding jig 7 is press-fitted into the coil, the bulge B of the coil insulating layer generated in the vicinity of the end face of the coil core is crushed and removed, and then the insulating resin is impregnated and cured. A stator coil with no bulges in the layers can be obtained.

4: Stator core 41: Slot 5: Stator coil 53: Wire coil 56: Main insulation layer 57a: Heat-shrinkable slot corona prevention layer 59: Insulation protection layer

Claims (3)

  A stator coil of a rotating electric machine that performs insulation treatment by impregnating and hardening an insulating resin in a state where a stator coil in which a main insulating layer is formed by winding a tape insulating material around the whole wire coil is mounted in a slot of the stator core In this manufacturing method, the stator core of the stator coil is interposed between the core pressing member protruding from the axial end surface of the stator core to which the stator coil is mounted and the stator coil protruding from the stator core. A stator coil for a rotating electrical machine, wherein a jig for pressing the vicinity of the end face in the axial direction is inserted and then impregnated and hardened with an insulating resin, and the jig is removed after the treatment is completed. Manufacturing method. 2. The manufacturing method according to claim 1, wherein the jig has a surface made of a fluororesin.   The manufacturing method according to claim 1, wherein the jig is inserted through a release material.

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