JP2014155369A - Method and device for impregnating stator coil with varnish and stator coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a stator core from being contaminated by varnish with which a stator coil is impregnated.SOLUTION: A stator coil 2 is wound around a slot 3A which is formed inside of a cylindrical stator core 3, and coil ends 2A, 2B extrude outside from the stator core 3. After winding, varnish is dripped from nozzles 5A, 5B, 6A, 6B to the coil ends 2A, 2B and the stator coil 2 within the stator core 3 is impregnated with the varnish. Recesses 8 formed on inner circumferential surfaces of the coil ends 2A, 2B store therein surplus of varnish dripped from the inner diameter nozzles 5B, 6B, thereby preventing the stator core 3 from being contaminated by varnish dripped from the inner diameter nozzles 5B, 6B.

Description

  The present invention relates to impregnation of varnish into a stator coil of an electric motor or a generator.

  A stator of an electric motor or a generator generally has a slot for winding a stator coil around the inner periphery of a cylindrical stator core. The stator coil wound around the slot is in a state in which the coil ends are projected from both axial ends of the stator core. In order to maintain the insulation and shape of the entire stator coil, the stator coil wound around the slot is impregnated with varnish.

  The stator coil is impregnated with varnish by dropping the varnish from the nozzle onto the coil end. The varnish dropped on the coil end penetrates between the coil wires in the slot by capillary action, and then solidifies to coat the stator coil. The nozzle includes an outer diameter nozzle that drops varnish on the outer periphery of the coil end and an inner diameter nozzle that drops varnish on the inner periphery of the coil end. All stator coils wound around the stator core can be impregnated with the varnish by rotating the stator core while dropping the varnish from the outer diameter nozzle and the inner diameter nozzle.

  At this time, if the amount of varnish dripping is too small, the coating of the stator coil in the slot becomes insufficient. If the amount of varnish dripping is excessive, surplus varnish that cannot penetrate the stator coil will drip or scatter from the stator coil, and will adhere to the inner periphery and end face of the stator core, which will have an undesirable effect on the subsequent stator manufacturing process. Effect.

  In order to accurately control the amount of varnish impregnation into the stator coil, Patent Document 1 measures the varnish impregnation state in the slot for each phase of the distributed winding stator coil, and drops the varnish from the nozzle based on the measured value. Teaches to determine the amount. According to this method, the stator coil can be impregnated with the varnish without any need.

JP 2009-201273 A

  However, in order to apply this conventional technique, for example, the impregnation state of the varnish must be measured by a break test or the like, and there is a problem that much labor and cost are required to determine an appropriate supply amount of the varnish. there were.

  Accordingly, an object of the present invention is to realize a structure in which when the varnish is impregnated into the stator coil, the varnish is not easily dropped or scattered from the stator coil.

  In order to achieve the above object, the present invention provides a slot in which a varnish is dropped from a nozzle onto a coil end protruding outward from a stator core of a stator coil wound around a slot formed inside a cylindrical stator core. A method for impregnating a varnish into a stator coil is provided.

  In the impregnation method, a concave portion is formed on the inner peripheral surface of the coil end prior to the dropping of the varnish by the nozzle.

  The varnish dripped from the nozzle to the coil end is temporarily stored in the recess and then impregnated in the stator coil. Even when the dripping amount of the varnish exceeds the impregnation amount, the concave portion temporarily stores the excess varnish, so that it is possible to prevent a problem that the excess varnish hangs down from the coil end or is scattered and contaminates the steer core.

It is a perspective view of the impregnation mechanism of the stator coil and varnish by this invention. It is a schematic longitudinal cross-sectional view of the stator explaining the impregnation process of a varnish. It is a schematic longitudinal cross-sectional view of the coil end of the stator coil which shows the recessed part by this invention. It is a schematic longitudinal cross-sectional view of the coil end principal part of the stator coil explaining the formation process of the recessed part by this invention. It is a perspective view of the coil end of the stator coil which shows the recessed part by this invention. It is a longitudinal cross-sectional view of the recessed part explaining the level | step difference of the both sides of a recessed part.

  Referring to FIG. 1, a stator 1 of an electric motor or a generator includes a cylindrical stator core 3. Slots 3A extending in the axial direction are formed in the stator core 3 at equal angular intervals, and the stator coil 2 is wound around the stator core 3 using the slots 3A.

  The motor or generator to which the stator 1 is applied is for a three-phase alternating current consisting of a U phase, a V phase, and a W phase, and the stator coil 2 is a coil of a plurality of groups in which the U phase, V phase, and W phase coils are grouped. Consists of. Each phase coil is connected to a lead wire 4.

  Each of the U-phase, V-phase, and W-phase coils has coil ends 2 </ b> A and 2 </ b> B that protrude outward from both axial ends of the stator core 3. Each coil bends approximately 180 degrees at the coil ends 2A and 2B.

  In order to maintain the overall insulation and shape of the stator coil 2, the stator coil 2 that has been wound is covered with a varnish. The varnish is performed by a varnish impregnation mechanism. In the varnish impregnation step, the stator coil 2 is held in a state where the central axis is horizontal as shown in the figure. In this state, the coil ends 2A and 2B protrude from the stator core 3 on both sides in the horizontal direction.

  The varnish impregnation mechanism includes an outer diameter nozzle 5A and an inner diameter nozzle 5B connected to the varnish supply pipe 10, and an outer diameter nozzle 6A and an inner diameter nozzle 6B connected to the varnish supply pipe 9.

  The varnish supply pipe 10, the outer diameter nozzle 5A, and the inner diameter nozzle 5B are disposed in the vicinity of the coil end 2A, and the varnish supply pipe 9, the outer diameter nozzle 6A, and the inner diameter nozzle 6B are disposed in the vicinity of the coil end 2B.

  The outer diameter nozzle 5A (6A) is disposed above the outer periphery of the coil end 2A (2B) protruding in the horizontal direction from the stator core 3, and a predetermined amount of varnish is dropped toward the outer periphery of the coil end 2A (2B). To do. The inner diameter nozzles 5B and 6B enter the inside of the coil end 2A (2B) from the axial direction, and drop a predetermined amount of varnish toward the inner periphery of the coil end 2A (2B).

  Referring to FIG. 2, the varnish dripped onto the portions corresponding to the top and bottom of the coil ends 2A and 2B in this way penetrates into the gaps of the coil windings as indicated by the arrows in the figure by capillary action. And reaches the center of the stator coil 2 inside the slot 3A.

  The inner periphery of the stator core 3 is supported by a support mechanism 12 fixed to the rotating shaft 7. The stator 1 is rotated and displaced integrally with the support mechanism 12 according to the rotation of the rotating shaft 7. On the other hand, the outer diameter nozzles 5A and 6A and the inner diameter nozzles 5B and 6B drop varnish at fixed positions. As a result, varnish is successively dropped from the outer diameter nozzles 5A and 6A onto the portions corresponding to the tops of the rotating coil ends 2A and 2B. Further, varnish is sequentially dropped from the inner diameter nozzles 5B and 6B to the portions corresponding to the bottoms of the rotating coil ends 2A and 2B.

  In this manner, the varnish is impregnated over the entire circumference and the entire length of the stator coil 2 by dropping the varnish while rotating the stator core 3. That is, the varnish is impregnated over the entire length of all the U-phase, V-phase, and W-phase coils of the plurality of groups constituting the stator coil 2.

  At this time, if the amount of varnish dropped from the outer diameter nozzles 5A and 6A and the inner diameter nozzles 5B and 6B is too small, the varnish cannot reach the center of the stator coil 2, and the coating of the stator coil 2 becomes insufficient. If the amount of varnish dripping is increased in order to sufficiently cover the stator coil 2, excess varnish that cannot penetrate the stator coil 2 may drop off or scatter from the stator coil 2, and the inner periphery of the stator core 3. And may adhere to the end face and adversely affect the subsequent stator manufacturing process.

  Referring to FIG. 3, the stator coil 2 includes a recess 8 on the inner periphery of the coil ends 2A and 2B. The recess 8 is formed by the method described below.

  In the manufacturing process of the stator 1, after the winding of the coil to the stator core 3 is completed, the coil ends 2A and 2B are shaped prior to the varnish impregnation operation by the nozzles 5A, 5B, 6A, 6B. Specifically, as shown in FIG. 4, the molds 15 are arranged on the inner peripheral side and the outer peripheral side of the coil end 2 </ b> A (2 </ b> B), and the coil end 2 </ b> A (2 </ b> B) is sandwiched in the radial direction by these molds 15. Thus, the coil end 2A (2B) is shaped into a predetermined shape. Protrusions 14 are formed in advance on the inner peripheral mold 15 used in this shaping step. Thereby, the recessed part 8 of the shape corresponding to the processus | protrusion 14 is formed in the internal peripheral surface of coil end 2A (2B) after shaping.

  In addition, regarding the arrangement of the U-phase, V-phase, and W-phase coils of each group, when a specific phase is arranged closer to the center than the other phases, a recess is formed in the coil of the phase arranged closest to the center. 8 may be formed. In the stator coil 2 shown in FIGS. 3 and 4, a recess 8 is formed in the W-phase coil of each group. Thus, by forming the recess 8 only in the phase arranged at the position closest to the center, the operation of forming the recess 8 can be easily performed.

  If the concave portion 8 is formed in the stator coil 2, the varnish dripped from the inner diameter nozzle 5B in the step of impregnating the stator coil 2 with the varnish is received by the concave portion 8 at a position corresponding to the bottom portion of the coil end 2A. The varnish is temporarily stored in the recess 8 and then infiltrates the gap between the coil windings and permeates into the central portion of the stator coil 2 inside the slot 3A by capillary action. The same applies to the varnish dropped from the inner diameter nozzle 6B.

  At this time, for example, it is assumed that the amount of varnish dropped from the inner diameter nozzle 5B (6B) exceeds the amount of penetration. In this case as well, the surplus of the dropped varnish is stored in the recess 8 and does not sag or scatter from the stator coil 2 to contaminate the stator core 3. The varnish stored in the recess 8 permeates toward the center of the stator coil 2 over time.

  On the other hand, with respect to the varnish dripping from the outer diameter nozzle 5A (6A) to the top of the coil end 2A (2B), since the concave portion 8 corresponding to the dropping position faces downward, the varnish cannot be stored in the concave portion 8. . However, when the varnish dripped onto the top of the coil end 2A (2B) does not penetrate the coil end 2A (2B) and overflows to the outside of the coil end 2A (2B), the stator core 3 is contaminated by the overflow varnish. Don't worry.

  In this way, the recess 8 at the position corresponding to the bottom of the coil end 2A (2B) stores the surplus varnish dripping from the inner diameter nozzle 5B (6B), so that the surplus varnish droops from the stator coil 2. It is possible to prevent a problem that the stator core 3 is contaminated by being scattered or scattered.

  Referring to FIG. 5, the recess 8 formed on the inner periphery of the coil end 2A (2B) is preferably formed independently for each of a plurality of groups. In the coil ends 2A and 2B of the stator coil 2, the boundary portion 13 of each group is a region where no coil exists, as shown in the figure. When the concave portion 8 is formed using the mold 15, if the concave portion 8 is formed as an annular groove, the varnish dripped into the concave portion 8 flows out from the boundary portion 13 to the outside of the concave portion 8, and the concave portion 8 cannot store the varnish. There is sex. By forming the recesses 8 independently for each group, it is possible to ensure the varnish storage function of the recesses 8.

  Referring to FIG. 6, the coil located on the opposite side of the recess 8 with respect to the diameter of the inner peripheral surface 2 </ b> C of the coil end 2 </ b> A (2 </ b> B) between the recess 8 and the stator core 3 with respect to the longitudinal section of the recess 8. It is desirable to set the dimensions of the mold 15 used in the shaping process of the coil end 2A (2B) in advance so that the diameter of the inner peripheral surface 2D of the end 2A (2B) is slightly larger.

  When the concave portion 8 is formed using the mold 15 having the dimensions set as described above, a step as shown in the figure is generated between the inner peripheral surfaces 2C and 2D. This step serves to guide the varnish overflowing from the recess 8 to the outside in the axial direction of the stator coil 2. If this step is provided, even when the varnish overflows from the recess 8, the varnish falls down to the outside of the stator core 3, so that the stator core 3 can be prevented from being contaminated by the varnish overflowing from the recess 8.

  As described above, the varnish impregnation method and impregnation apparatus according to the present invention forms the recesses 8 on the inner peripheral surfaces of the coil ends 2A and 2B prior to the dripping of the varnish by the nozzles 5A, 5B, 6A, 6B. As a result, the varnish dripped from the inner diameter nozzles 5B and 6B is stored in the concave portion 8, and infiltrates the gaps of the coil windings by capillary action over time, and into the central part of the stator coil 2 inside the slot 3A by capillary action. Will penetrate. Therefore, even when the appropriate amount of varnish exceeds the amount of penetration, it is possible to prevent the excess varnish from immediately dropping from the stator coil 2 or scattering. As a result, it is possible to create an environment in which the stator core 3 is not easily contaminated by the varnish with a simple configuration.

  In the above embodiment, the mold 15 and the protrusion 14 constitute a recess forming mechanism of the varnish impregnation apparatus according to the present invention.

  As described above, the present invention has been described through specific embodiments. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various modifications or changes to these embodiments within the scope of the claims. For example, it is good also as a structure which performs the impregnation process of a varnish after fixing a stator core in a case by shrink fitting. Further, the formation position of the recess 8 is not limited to the W phase, but can be changed as appropriate depending on the coil structure, the configuration of the recess formation mechanism, and the like.

DESCRIPTION OF SYMBOLS 1 Stator 2 Stator coil 2A Coil end 2B Coil end 2C Inner peripheral surface 2D Inner peripheral surface 3 Stator core 3A Slot 4 Lead wire 5A Outer diameter nozzle 5B Inner diameter nozzle 6A Outer diameter nozzle 6B Inner diameter nozzle 7 Rotating shaft 8 Recess 9 Varnish supply pipe 10 Varnish supply pipe 12 Support mechanism 13 Boundary part 14 Protrusion 15 Mold

Claims (6)

A stator coil in which a varnish is dropped from a nozzle onto a coil end projecting outward from the stator core of a stator coil wound inside a slot formed inside a cylindrical stator core, and the stator coil in the slot is impregnated with the varnish. In the method of impregnating varnish into
A method for impregnating a varnish into a stator coil, wherein a concave portion is formed on an inner peripheral surface of a coil end prior to dripping of the varnish by a nozzle.   The method for impregnating a varnish into a stator coil according to claim 1, wherein the stator coil includes a plurality of groups of coils, and each of the plurality of groups includes the independent recess.   3. The method for impregnating a varnish into a stator coil according to claim 2, wherein each of the plurality of groups is formed of a plurality of phases of coils, and the concave portion is formed in a coil of a phase disposed closest to the center in the stator core.   The level | step difference was provided between the internal peripheral surface of the coil end extended from the said recessed part to the said stator core in the axial direction opposite direction, and the internal peripheral surface of the coil end extended from the said recessed part to the said stator core. A method for impregnating a varnish into a stator coil according to claim 1.   In a stator coil wound around a slot formed inside a cylindrical stator core, a concave portion is formed on the inner peripheral surface of the coil end protruding outward from the stator core and temporarily stores the varnish dropped on the coil end. A stator coil comprising a stator coil. A stator coil in which a varnish is dropped from a nozzle onto a coil end projecting outward from the stator core of a stator coil wound inside a slot formed inside a cylindrical stator core, and the stator coil in the slot is impregnated with the varnish. In the varnish impregnation equipment
An apparatus for impregnating a varnish into a stator coil, comprising a recess forming mechanism for forming a recess on an inner peripheral surface of a coil end prior to the dropping of varnish by a nozzle.

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