JP2014108005A - Rotor, induction motor with the rotor and manufacturing method of rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor capable of appropriately reducing deformation of a short-circuit ring with rotational drive without using any reinforcement member, the rotor being configured by connecting a plurality of secondary conductors via the short-circuit ring.SOLUTION: A short-circuit ring 25 included in a rotor 20 is provided in such a mode that a rotary shaft 21 is inserted through a shaft hole 25A and can be integrally rotated. On an outer circumferential surface 21C of the rotary shaft 21, a first spray coating film 41 is formed which is insulative in a portion of the short-circuit ring 25 corresponding to an inner circumferential surface of the shaft hole 25A. The short-circuit ring 25 is firmly joined to the first spray-coating film 41 by casting, thereby regulating the radially outward movement thereof with rotational drive.

Description

  The present invention relates to a rotor in which a plurality of secondary conductors are connected by a short-circuit ring, an induction motor including the rotor, and a method for manufacturing the rotor.

  2. Description of the Related Art Conventionally, there is an induction motor including a rotor (for example, a squirrel-cage rotor) in which a plurality of secondary conductors inserted into a conductor slot of a rotor core are connected at their end faces with a short-circuit ring (end ring) at an end surface of the rotor core. In this type of rotor (rotor), deformation or the like may occur in the short-circuit ring due to centrifugal force accompanying rotation, and therefore a technique for preventing these is desired. For example, as disclosed in Patent Document 1, a reinforcing ring is fixed to a portion that is closer to the end in the axial direction than the short-circuit ring on the rotating shaft, and the deformation of the short-circuit ring is suppressed by the reinforcing ring. There is a rotor. In this rotor, deformation is suppressed by locking the inner peripheral surface of the reinforcing ring to the outer peripheral surface of the short-circuiting ring and restricting the movement toward the radially outer side of the short-circuiting ring by the reinforcing ring.

Japanese Patent Laid-Open No. 61-132063

  The reinforcing member intended to prevent the deformation of the short-circuited ring such as the above-described reinforcing ring is limited in the material used due to various factors. For example, the reinforcing member is required to have higher strength than the short-circuited ring, but it is preferable that the deformation mode due to the heat change is the same as the short-circuited ring. Therefore, for example, in the reinforcing ring of Patent Document 1 described above, ultra-duralumin is used as a material that has higher strength and the same thermal expansion coefficient than a short-circuit ring made of aluminum. However, the use of a reinforcing member that is restricted by such a material may lead to an increase in the manufacturing cost of the rotor, and thus the induction motor, and a technique that does not use the reinforcing member has been studied.

  Further, the above-described reinforcing ring is provided separately from the short-circuit ring, and is connected to the short-circuit ring only at a part on the outside in the radial direction, and the electrical resistance between the short-circuit ring is large. For this reason, the reinforcing ring does not function as a conductor for short-circuiting the secondary conductor like the short-circuited ring, and the effect is that the current density of the induced current flowing through the short-circuited ring is reduced, and further, the amount of heat generated by the induced current is reduced. Was not what you could expect. For these reasons, a technique that does not use a reinforcing member has been studied.

  The present invention relates to a rotor in which a plurality of secondary conductors are connected by a short-circuit ring, a rotor capable of suitably reducing deformation of the short-circuit ring accompanying rotation driving without using a reinforcing member, and an induction motor including the rotor, And a method of manufacturing a rotor.

  A rotor according to one aspect of the present invention includes a rotor core provided so as to be integrally rotatable with respect to a rotating shaft, a plurality of secondary conductors inserted through conductor slots provided in a circumferential direction of the rotor core, A short-circuiting ring that interconnects the ends of the secondary conductors at the end face of the rotor core in the axial direction of the shaft, the short-circuiting ring having a shaft hole through which the rotation shaft is inserted, and the rotation shaft Is characterized in that an insulating first film is formed on the outer peripheral surface corresponding to the inner peripheral surface of the shaft hole, and the inner peripheral surface of the shaft hole of the short-circuit ring is cast-bonded to the first film. To do.

  The rotor has a rotating shaft, a rotor core, a plurality of secondary conductors, and a short-circuit ring. The short-circuit ring is provided in such a manner that the rotary shaft is inserted into the shaft hole and can rotate integrally. A first film is formed on the outer peripheral surface of the rotating shaft at a portion corresponding to the inner peripheral surface of the shaft hole of the short-circuit ring. The coating referred to here is, for example, a coating formed by heating the sprayed material to be melted or nearly melted and sprayed onto the target portion (here, the outer peripheral surface of the rotating shaft), and is firmly attached to the target. This means that a bonded film is formed. The short-circuit ring is cast-bonded to the first film, and the insulating film and the short-circuit ring are firmly diffusion-bonded. In such a configuration, the inner circumferential surface of the shaft hole of the short-circuiting ring and the outer circumferential surface of the rotating shaft are firmly joined by the formation of the coating and the casting joining to the coating, and the movement toward the radially outer side of the short-circuiting ring can be restricted. As a result, it is possible to configure a rotor that can favorably suppress deformation of the short-circuit ring accompanying rotational driving without using a reinforcing member such as a reinforcing ring.

  In addition, since the short circuit ring generates heat by short-circuiting the induced current flowing through the secondary conductor, for example, it is required to increase the axial thickness (cross-sectional area) to reduce the electrical resistance. If the axial thickness is increased, problems such as deformation due to centrifugal force may occur. On the other hand, although a reinforcing member such as a reinforcing ring can suppress deformation of the short-circuited ring, it may not function as a conductor that short-circuits the secondary conductor, such as a short-circuited ring. There is a high possibility that it will not contribute to the reduction of loss due to On the other hand, according to the present invention, the short-circuit ring can be firmly fixed to the rotating shaft even if the short-circuit ring sufficiently secures the axial thickness (cross-sectional area) in order to reduce electrical resistance. The short-circuit ring can be stably held on the rotating shaft without using a reinforcing member that does not contribute to a reduction in loss.

  Moreover, the rotor which concerns on the other side surface of this invention is a rotor of Claim 1, Comprising: The rotor coat | cover further forms the 2nd film | membrane which has insulation on the end surface of the rotor core corresponding to a short circuit ring. The short-circuit ring is cast-bonded to the second film.

  In the rotor, in addition to the first film, a second film is further formed on the end face of the rotor core corresponding to the short-circuit ring, and the short-circuit ring is cast-bonded to the second film. Thereby, the short-circuit ring is firmly fixed also to the end face of the rotor core, so that not only the movement in the radial direction but also the movement in the axial direction is more reliably regulated. As a result, for example, it is possible to suppress the deformation that causes the short-circuit ring to turn away from the rotor core in the axial direction.

  A rotor machine according to another aspect of the present invention is the rotor according to claim 1 or 2, wherein the rotor core has a third insulating property on the inner wall of the conductor slot corresponding to the secondary conductor. A film is further formed, and the secondary conductor is cast-bonded to the third film.

  In the rotor, a third coating is further formed on the inner wall of the conductor slot of the rotor core corresponding to the secondary conductor, and the secondary conductor is cast-bonded to the third coating. Thereby, each secondary conductor connected with a short circuit ring is firmly fixed to a rotor core. Therefore, the short circuit ring is firmly fixed to the rotor core via the secondary conductor, so that the movement is restricted and the deformation accompanying the rotation is more reliably suppressed.

  A rotor machine according to another aspect of the present invention is the rotor according to any one of claims 1 to 3, wherein the first to third coatings are made of a ceramic spray material. .

  In the rotor, by forming each film using a ceramic sprayed material, it is possible to easily form an insulating film that is firmly bonded to each member.

  A rotor machine according to another aspect of the present invention is the rotor according to any one of claims 1 to 4, wherein the short-circuit ring and the secondary conductor are integrally die-cast. To do.

  In the rotor, when the short-circuit ring and the secondary conductor are die-cast, for example, the short-circuit ring is cast-bonded to the first film. Thereby, since formation of a short circuit ring and a secondary conductor, and casting joining can be implemented by the same process, a required man-hour can be reduced and the reduction of the manufacturing cost of the rotor which can suppress a deformation | transformation of a short circuit ring can be aimed at.

  A rotor according to another aspect of the present invention is the rotor according to any one of claims 1 to 5, wherein the short-circuiting ring has a substantially disc shape, and at least a part thereof is removed. A processing unit is provided.

  In the rotor, the short-circuiting ring is firmly fixed to the rotating shaft, and the processing part is formed so as to remove a part of the short-circuiting ring, thereby reducing the weight of the short-circuiting ring and increasing the rotational efficiency of the rotor. Can be reduced.

  Moreover, the induction motor which concerns on 1 side of this invention can reduce suitably the deformation | transformation of the short circuit ring accompanying a rotational drive, without using a reinforcement member by providing the rotor in any one of Claim 1 thru | or 6. An induction motor can be configured.

  Also, a method of manufacturing a rotor according to one aspect of the present invention includes a rotor core provided so as to be integrally rotatable with respect to a rotating shaft, and a plurality of secondary parts inserted through conductor slots provided dispersed in the circumferential direction of the rotor core. A method of manufacturing a rotor having a conductor and a short-circuiting ring that interconnects ends of secondary conductors at the end face of the rotor core in the axial direction of the rotation shaft, the shaft hole of the short-circuiting ring through which the rotation shaft is inserted Forming a first coating having an insulating property on the outer peripheral surface of the rotating shaft corresponding to the inner peripheral surface of the rotor, and fixing the rotor core so as to be integrally rotatable with respect to the rotating shaft on which the first coating is formed. And a step of casting and joining the inner peripheral surface of the shaft hole of the short-circuit ring to the first film.

  In the rotor manufacturing method, it is possible to manufacture a rotor that can suitably reduce the deformation of the short-circuited ring accompanying rotation driving without using a reinforcing member. In addition, since the first film is formed on the rotating shaft before the rotor core is fixed, it is easy to handle the rotating shaft in the manufacturing process, and the film can be formed with high accuracy.

  Also, a method of manufacturing a rotor according to one aspect of the present invention includes a rotor core provided so as to be integrally rotatable with respect to a rotating shaft, and a plurality of secondary parts inserted through conductor slots provided dispersed in the circumferential direction of the rotor core. A method of manufacturing a rotor having a conductor and a short-circuiting ring that interconnects ends of secondary conductors at the end face of the rotor core in the axial direction of the rotating shaft, the rotor core being integrally rotatable with respect to the rotating shaft A first coating having an insulating property on the outer peripheral surface of the rotating shaft corresponding to the inner peripheral surface of the shaft hole of the short-circuit ring through which the rotating shaft is inserted in the outer peripheral surface of the rotating shaft to which the rotor core is fixed; And a step of casting and joining the inner peripheral surface of the shaft hole of the short-circuiting ring to the first film.

  In the rotor manufacturing method, it is possible to manufacture a rotor that can suitably reduce the deformation of the short-circuited ring accompanying rotation driving without using a reinforcing member. Further, since the first film is formed on the rotor after the rotor core is fixed, the film can be formed on other portions, for example, the rotor core in the same process as the first film. As a result, the number of steps for forming the film can be reduced and the manufacturing cost can be reduced.

  The present invention relates to a rotor in which a plurality of secondary conductors are connected by a short-circuiting ring, and a rotor that can suitably reduce deformation of the short-circuiting ring accompanying rotation driving without using a reinforcing member, and an induction including the rotor An electric motor and a method for manufacturing a rotor can be provided.

It is a schematic block diagram of the induction motor which concerns on embodiment. It is a top view which shows the structure of the short circuit ring which concerns on embodiment. It is a fragmentary sectional view showing the composition of the rotor concerning an embodiment. It is a fragmentary sectional view which shows the structure of another rotor, and is sectional drawing in the AA of FIG. It is a top view which shows the structure of another short circuit ring. It is a top view which shows the structure of another short circuit ring.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
First, the configuration of the induction motor 1 according to the embodiment will be described in detail with reference to FIGS. The induction motor 1 of the embodiment is a cage type three-phase induction motor. The induction motor 1 has a stator 10 and a rotor 20.

  The stator 10 includes a stator core 11 fixed to an inner peripheral surface of a case (not shown), and a coil 12 wound around the stator core 11. The stator core 11 is formed by laminating a plurality of electromagnetic steel plates and is formed in a substantially cylindrical shape. The stator core 11 is formed with a plurality of slots (not shown) that are distributed in the circumferential direction and penetrate along the axial direction. A coil 12 is wound around this slot. The coil 12 includes coils corresponding to three-phase alternating current phases (U-phase, V-phase, and W-phase), and rotating magnetic flux is generated by supplying alternating current of each phase. A rotor 20 is disposed inside the stator 10 in the radial direction.

  The rotor 20 is configured as a cage rotor having a rotating shaft 21, a rotor core 30, a secondary conductor (rotor bar) 23, and a pair of short-circuit rings 25 and 26. The rotating shaft 21 is rotatably supported by a bearing (not shown). The rotary shaft 21 is formed with a first large-diameter portion 21A to which the short-circuit rings 25 and 26 are fixed, and a second large-diameter portion 21B to which the rotor core 30 is fixed. The second large diameter portion 21B is formed at the central portion in the axial direction of the rotary shaft 21, and the first large diameter portion 21A is formed on both axial sides of the second large diameter portion 21B. The first large-diameter portion 21A has a cylindrical shape with a larger radius than the portion of the rotating shaft 21 where the rotor core 30 and the short-circuit rings 25 and 26 are not mounted. Further, the second large diameter portion 21B has a cylindrical shape with a larger radius than the first large diameter portion 21A.

  The rotor core 30 is formed by laminating a plurality of electromagnetic steel plates and has a substantially cylindrical shape. The rotor core 30 is provided so as to be able to rotate integrally with the rotary shaft 21 by being inserted into and fixed to the through hole 31 provided in the central portion in the radial direction through the second large diameter portion 21B of the rotary shaft 21. ing. The outer peripheral surface of the rotor core 30 and the inner peripheral surface (the surface on the rotating shaft 21 side) of the stator 10 are opposed to each other with a predetermined interval in the radial direction. The rotor 20 is supported so as to be rotatable around the axis of the rotation shaft 21 on the radially inner side of the stator 10.

  A plurality of insertion holes 32 are provided in the rotor core 30 in the axial direction of the rotary shaft 21. The insertion holes 32 are formed at equal intervals along the circumferential direction of the rotor core 30 so as to surround the periphery of the through hole 31 through which the rotary shaft 21 is inserted. Each insertion hole 32 is filled with a secondary conductor 23 made of aluminum. The secondary conductor 23 is formed in a solid rod shape, and the first end 23A on one side (right side in the drawing) in the axial direction protrudes from the first end face 33 side of the rotor core 30, and the other second end 23B. Is a mode in which it protrudes from the other second end face 34 side of the rotor core 30.

  At both ends of the rotor core 30, short-circuit rings 25 and 26 having substantially the same shape of a disk are provided. The short-circuit rings 25 and 26 are members called end-to-end rings or end rings. A portion of the first end portion 23A of the secondary conductor 23 that protrudes from the first end surface 33 of the rotor core 30 is joined to the short-circuit ring 25, and the first end portion 23A and the short-circuit ring 25 are integrally formed. Further, the second end portion 23B of the secondary conductor 23 is joined to the short-circuit ring 26 at a portion protruding from the second end surface 34 of the rotor core 30, and the second end portion 23B and the short-circuit ring 26 are integrally formed. Therefore, each secondary conductor 23 is short-circuited by being connected to the pair of short-circuit rings 25 and 26. The secondary conductor 23 and the short-circuit rings 25 and 26 are integrally formed using, for example, aluminum die casting.

  FIG. 2 is a view of the short-circuit ring 25 as viewed from the outside in the axial direction of the rotating shaft 21. As shown in FIG. 2, in the short-circuit ring 25, the first large-diameter portion 21 </ b> A of the rotating shaft 21 is inserted into a shaft hole 25 </ b> A that is provided in the central portion in the radial direction and penetrates in the axial direction. A ceramic first spray coating 41 is formed on the outer peripheral surface 21C of the first large diameter portion 21A (rotary shaft 21) over the entire circumference of the first large diameter portion 21A. As shown in FIG. 3, the first thermal spray coating 41 has a cylindrical shape formed on the outer peripheral surface 21 </ b> C along the axial direction so as to face the inner peripheral surface of the shaft hole 25 </ b> A of the short-circuit ring 25. . Therefore, the short circuit ring 25 is electrically insulated from the rotating shaft 21 by providing the first thermal spray coating 41 between the first large diameter portion 21 </ b> A. The short ring 25 is fixed to the first large diameter portion 21 </ b> A by diffusion bonding by casting bonding to the first thermal spray coating 41. Note that the casting joining here refers to, for example, a high-pressure casting method applied to the joining of the short-circuited ring 25 made of a metal member and the first thermal spray coating 41 having an insulating property, and the metal member is in a molten state. This is a method of injecting onto the joining surface and joining while applying pressure.

  In addition, the rotor core 30 is formed with a second sprayed coating 42 having insulating properties on the first end face 33 in the axial direction facing the short-circuit ring 25. The second thermal spray coating 42 is formed on the entire portion of the first end face 33 facing the short-circuit ring 25. Therefore, the second thermal spray coating 42 is provided between the short-circuit ring 25 and the first end surface 33 so as to be electrically insulated from the rotor core 30. Further, the short ring 25 is fixed to the rotor core 30 by diffusion bonding by casting bonding to the second thermal spray coating 42. As shown in FIG. 1, the short-circuit ring 26 is joined to the first large-diameter portion 21 </ b> A of the rotating shaft 21 via the first thermal spray coating 41, similarly to the short-circuit ring 25. The short-circuit ring 26 is joined to the second end surface 34 of the rotor core 30 via a second sprayed coating 42.

  As shown in FIG. 3, the rotor core 30 has a third sprayed coating 43 having insulating properties on the inner wall of the insertion hole 32. The third sprayed coating 43 is formed over the entire circumference of the inner wall and has a cylindrical shape. Accordingly, the secondary conductor 23 is electrically insulated from the rotor core 30 by providing the third thermal spray coating 43 between the secondary conductor 23 and the insertion hole 32. In addition, the secondary conductor 23 is fixed to the rotor core 30 by diffusion bonding by casting bonding to the third thermal spray coating 43.

  The induction motor 1 configured as described above includes a rotating magnetic flux generated when a three-phase alternating current is supplied to the coil 12 of the stator 10, and an induced current generated in the secondary conductor 23 of the rotor 20. The rotor 20 is driven to rotate by interlinking.

  The short ring 25 is fixed so as to be integrally rotatable in a mode in which the rotary shaft 21 is inserted into the shaft hole 25A. On the outer peripheral surface 21C of the first large-diameter portion 21A of the rotating shaft 21, the first sprayed coating is formed over the entire portion corresponding to the inner peripheral surface of the shaft hole 25A of the short-circuit ring 25 (the entire periphery of the outer peripheral surface 21C). 41 is formed, and the first thermal spray coating 41 is firmly bonded to the outer peripheral surface 21C. The short-circuit ring 25 is firmly bonded to the first thermal spray coating 41 by diffusion bonding by casting. In such a configuration, the inner peripheral surface of the shaft hole 25 </ b> A of the short-circuit ring 25 and the outer peripheral surface 21 </ b> C of the rotary shaft 21 are firmly bonded by forming the first sprayed coating 41 and casting the first sprayed coating 41. Is done. Similarly, the short circuit ring 26 is firmly joined to the rotating shaft 21 via the first thermal spray coating 41. Therefore, when a force toward the radially outer side is applied to the short-circuiting rings 25 and 26 due to the centrifugal force accompanying the rotational drive of the rotor 20, the shaft hole 25A is formed in the radially inner portion of the short-circuiting rings 25 and 26. Since the portion is firmly joined to the rotating shaft 21, movement toward the radially outer side is restricted. As a result, without using a reinforcing member such as a reinforcing ring, deformation of the short-circuit rings 25 and 26 accompanying rotation can be suitably suppressed.

  Further, in the rotor 20, the second sprayed coating 42 is formed on the entire surface facing the short-circuiting rings 25 and 26 on the first and second end faces 33 and 34 of the rotor core 30 so that the short-circuiting rings 25 and 26 are the second. The thermal spray coating 42 is cast and joined to the rotor core 30. Therefore, the short-circuit rings 25 and 26 are firmly fixed to the first and second end faces 33 and 34 of the rotor core 30, so that not only the movement in the radial direction but also the movement in the axial direction can be performed more reliably. Be regulated. As a result, for example, the deformation that causes the short-circuit rings 25 and 26 to be separated from the rotor core 30 in the axial direction can be suppressed.

  Further, in the rotor 20, the third sprayed coating 43 is formed on the entire inner wall corresponding to the secondary conductor 23 on the inner wall of the insertion hole 32 of the rotor core 30, and the secondary conductor 23 is cast on the third sprayed coating 43. Joined to the rotor core 30. The secondary conductor 23 is penetrated in the axial direction with respect to the rotor core 30, and the first and second end portions 23 </ b> A and 23 </ b> B are integrally formed with the pair of short-circuit rings 25 and 26. By firmly fixing the secondary conductor 23 to the rotor core 30, the short-circuit rings 25 and 26 are firmly fixed to the rotor core 30 via the secondary conductor 23. Accordingly, the movement of the short-circuit rings 25 and 26 is restricted, and deformation due to rotation is more reliably suppressed.

Next, an example of a method for manufacturing the rotor 20 will be described.
As a manufacturing process of the rotor 20, for example, the rotor core 30 on which the second and third thermal spray coatings 42 and 43 are formed is assembled to the rotary shaft 21 on which the first thermal spray coating 41 is formed. Note that the first to third sprayed coatings 41 to 43 may be formed after the rotor core 30 is assembled to the rotating shaft 21. The rotating shaft 21 is formed in a substantially cylindrical shape in which the first and second large diameter portions 21A and 21B are formed by cutting or forging using, for example, stainless steel (SUS).

  The first thermal spray coating 41 is formed, for example, by heating a thermal spray material to be in a molten state or a state close to melting, and spraying the outer peripheral surface 21C of the first large diameter portion 21A. In addition, the thermal spray coating on the end surface in the axial direction of the second large diameter portion 21B shown by the thermal spray coating portion 51 in FIG. 3, in other words, the second thermal spray coating 42 in the rotor 20 after manufacture is the second large diameter portion. You may form the part used as the aspect extended to the end surface of 21B at this process. The thermal spray coating portion 51 joins the second large diameter portion 21B and the short-circuit rings 25 and 26 by casting joining described later. Further, the sprayed coating 51 need not be formed.

  Similar to the first thermal spray coating 41, the second and third thermal spray coatings 42 and 43 are formed on the first and second end surfaces 33 and 34 of the rotor core 30 on which the electromagnetic steel plates are laminated and on the inner wall of the insertion hole 32. Sprayed material is formed by spraying. In addition, when an insulating film is formed in advance on the surface of each electromagnetic steel sheet constituting the rotor core 30, for example, the second and third thermal sprayed films 42 and 43 may be formed on the insulating film. Good. In addition, the electromagnetic steel sheet has a configuration in which the insulating coating is removed from the portion where the second and third thermal spray coatings 42 and 43 are formed, and the second and third thermal spray coatings 42 and 43 are directly sprayed onto the electrical steel plate. May be formed.

  As a material of the first to third thermal spray coatings 41 to 43, for example, an oxide-based ceramic thermal spray material, a carbide-based ceramic thermal spray material, or the like can be used. More specifically, the oxide-based ceramic sprayed material is alumina, titania, zirconia, chromia, yttria, or a compound containing these. Further, the carbide-based ceramic sprayed material is tungsten carbide, chromium carbide, or a compound containing these with cobalt, nickel chromium, or the like.

  Next, the rotor core 30 on which the second and third thermal spray coatings 42 and 43 are formed is fixed to the rotating shaft 21 on which the first thermal spray coating 41 is formed. The through hole 31 of the rotor core 30 is formed in accordance with the outer diameter of the second large diameter portion 21B having a larger radius than the first large diameter portion 21A. Therefore, for example, when the second large diameter portion 21B is shrink-fitted to the rotor core 30, the rotary shaft 21 is not damaged without damaging the first thermal spray coating 41 formed on the outer peripheral surface 21C of the first large diameter portion 21A. The rotor core 30 can be suitably fixed.

  Next, aluminum die casting is performed on the rotor core 30 fixed to the rotating shaft 21 to form the short-circuit rings 25 and 26 and the secondary conductor 23. In die-casting, the short rings 25 and 26 and the secondary conductor 23 are formed using a mold, and casting joining to the first to third thermal spray coatings 41 to 43 is performed. More specifically, for example, the mold and the first to third sprayed coatings 41 to 43 (rotary shaft 21) are preheated to dissolve aluminum and hold it in a liquid state. Next, the rotating shaft 21 to which the rotor core 30 is fixed is placed in a mold, and the short-circuit rings 25 and 26 and the secondary conductor 23 are formed while injecting and pressurizing liquid aluminum. At this time, the joining portions of the short-circuit rings 25 and 26 and the secondary conductor 23 with respect to the first to third thermal spray coatings 41 to 43 are diffusion-bonded. In this way, the rotor 20 shown in FIG. 1 is formed.

According to the above-described embodiment, the following effects can be obtained.
(1) The short-circuit rings 25 and 26 are firmly joined to the rotating shaft 21 via the first sprayed coating 41. Further, the short-circuit rings 25 and 26 are firmly joined to the rotor core 30 via the second thermal spray coating 42. Further, each of the short-circuiting rings 25 and 26 is firmly joined to the rotor core 30 via the third spray coating 43 with each secondary conductor 23 formed integrally with the short-circuiting rings 25 and 26. Therefore, the short-circuit rings 25 and 26 are firmly fixed to the rotary shaft 21 or the rotor core 30 fixed to the rotary shaft 21 via the first to third thermal spray coatings 41 to 43, and the centrifugal force accompanying the rotational drive. The deformation due to is suppressed. As a result, it is possible to suppress deformation accompanying rotation without using a reinforcing member such as a reinforcing ring.
Further, since the short-circuit rings 25 and 26 generate heat by short-circuiting the induced current flowing through the secondary conductor 23, for example, the electrical resistance can be reduced by increasing the axial thickness (cross-sectional area). As required, when the axial thickness is increased, there is a risk of problems such as deformation due to centrifugal force. On the other hand, although a reinforcing member such as a reinforcing ring can suppress deformation of the short-circuited ring, it may not function as a conductor that short-circuits the secondary conductor 23 like the short-circuited rings 25 and 26. There is a high possibility that it does not contribute to a reduction in loss due to heat generation of the short-circuit rings 25 and 26. On the other hand, in the rotor 20 of the present embodiment, even if the short-circuiting rings 25 and 26 have a sufficient axial thickness (cross-sectional area) to reduce the electrical resistance, the short-circuiting rings 25 and 26 are provided. Since the rotary shaft 21 can be firmly fixed, the short-circuit rings 25 and 26 can be stably held on the rotary shaft 21 without using a reinforcing member that does not contribute to the reduction of loss.

(2) A ceramic sprayed material is used as a material of the first to third sprayed coatings 41 to 43, and an insulating sprayed coating that is firmly bonded to each member can be easily formed.
(3) When the short-circuit rings 25 and 26 and the secondary conductor 23 are integrally die-cast, the short-circuit rings 25 and 26 are the third and second sprayed coatings 41 and 42, and the secondary conductor 23 is the third. The thermal spray coating 43 is cast-joined. Thereby, since formation of the short-circuiting rings 25 and 26 and the secondary conductor 23 and casting joining can be performed in the same process, the required man-hours can be reduced, and the manufacture of the rotor 20 that can suitably suppress deformation of the short-circuiting rings 25 and 26. Cost can be reduced.

(4) As a manufacturing process of the rotor 20, the rotor core 30 on which the second and third thermal spray coatings 42 and 43 are formed is assembled to the rotary shaft 21 on which the first thermal spray coating 41 is formed. Thereby, since the 1st-3rd thermal spray coating 41-43 is formed with respect to each of the rotating shaft 21 and the rotor core 30 before an assembly | attachment, the handling in the manufacturing process of the rotating shaft 21 and the rotor core 30 becomes easy, and it is accurate. It becomes possible to form the 1st-3rd sprayed coatings 41-43.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention.
For example, in the manufacturing process of the rotors 20 and 100 of the above-described embodiment, the rotor core 30 on which the second and third sprayed coatings 42 and 43 are formed on the rotating shaft 21 on which the first sprayed coating 41 is formed. Although it assembled | attached, you may form the 1st-3rd sprayed coatings 41-43 in the same process, after attaching the rotor core 30 to the rotating shaft 21 previously. Thereby, it becomes possible to reduce the number of steps for forming the first to third thermal spray coatings 41 to 43 and to reduce the manufacturing cost.

For example, as shown in FIG. 4, it is good also as a structure where the short circuit rings 25 and 26 were provided with the cooling fin. In the rotor 101 shown in FIG. 4, for example, the cooling fin 120 is integrally die-cast on the short-circuit ring 25 of the above-described embodiment. 4 is a partial cross-sectional view taken along line AA in FIG. As shown in FIGS. 4 and 5, the cooling fin 120 includes a cylindrical portion 121 in which a part of the main body portion 25 </ b> B of the short-circuiting ring 25 extends outward in the axial direction so as to surround the rotating shaft 21, and the cylinder. Fin portions 122 formed radially from the portion 121 toward the radially outer side. The axial length of the first large-diameter portion 21A of the rotary shaft 21 is extended according to the length of the cylindrical portion 121, and the cylindrical portion 121 and the first large-diameter portion 21A are the first thermal spray coating. 41 is joined. The fin portion 122 has a plate shape that is erected and joined to the end surface in the axial direction of the disc-shaped main body portion 25B. As shown in FIG. 5, the radially outer portion of the fin portion 122 is formed from the radially outer peripheral surface of the main body portion 25 </ b> B to a position that is radially inward by a predetermined interval. In addition, a plurality of fin portions 122 (eight in the drawing) are formed at equal intervals in the circumferential direction of the short-circuit ring 25.

  Here, even in the short-circuit ring 25 including the cooling fins 120 as described above, there is a possibility that deformation occurs due to the centrifugal force accompanying the rotational drive. Therefore, such a cooling fin 120 is deformed by centrifugal force by joining its inner diameter portion (cylindrical portion 121) to the rotating shaft 21 (first large diameter portion 21A) via the first thermal spray coating 41. Can be suitably suppressed. Even if the cooling fin 120 is provided separately from the main body portion 25B, the same effect can be obtained by joining via the first thermal spray coating 41.

  The configuration of the short-circuit rings 25 and 26 in the above embodiment is an example, and may be changed as appropriate. For example, in the above-described embodiment, the short-circuiting ring 25 is configured in a disk shape, but the present invention is not limited to this, and as shown in FIG. May be. The processing part 131 shown in FIG. 6 is formed so as to penetrate the short-circuit ring 25 in the axial direction, and the shape orthogonal to the axial direction forms a fan shape whose width in the circumferential direction increases radially outward. A plurality (8 in FIG. 6) of processed portions 131 are formed at equal intervals along the circumferential direction of the short-circuit ring 25. Each process part 131 is formed in the position used between the circumferential directions of each secondary conductor 23 connected with the short circuit ring 25, for example.

  In such a configuration, the short circuit ring 25 is firmly fixed to the rotating shaft 21 by the first thermal spray coating 41, and the processing portion 131 is formed so as to partially cut the short circuit ring 25, thereby forming the short circuit ring 25. The weight of the rotor 20 can be reduced, the rotation efficiency of the rotor 20 can be increased, and the centrifugal force acting on the short-circuit ring 25 can be reduced. Further, the processing portion 131 serves as an electrical resistance portion against an induced current that short-circuits the short-circuit ring 25. At the time of rotational driving, the induced current generated in the secondary conductors 23 preferably flows while being short-circuited in the short-circuit ring 25 so as to connect the secondary conductors 23. In the configuration shown in FIG. 6, each secondary conductor 23 is connected to the radially outer portion of the short-circuit ring 25, and the outer peripheral portion of the short-circuit ring 25 can be short-circuited so that the induced current connects each secondary conductor 23. preferable. On the other hand, in the short-circuit ring 25 shown in FIG. 6, the processed portion 131 serving as an electric resistance is formed in a portion which is radially inward between the circumferential directions of the secondary conductors 23, and the induced current is supplied to each two A rectifying effect can be obtained that flows appropriately between the secondary conductors 23. Note that the shape, number, and the like of the processing portion 131 illustrated in FIG.

  In the said embodiment, the area | region which formed the 1st-3rd sprayed coatings 41-43 is an example, and may be changed suitably. For example, although the first sprayed coating 41 is formed over the entire circumference of the outer peripheral surface 21C, it may be formed on a part of the outer peripheral surface 21C.

The material of the short-circuit rings 25 and 26 and the secondary conductor 23 is not limited to aluminum, but may be an aluminum-based alloy or other metal such as copper or a copper-based alloy.
In the above-described embodiment, casting joining is performed when the entire short-circuiting ring 25 is formed by die casting. However, for example, only a part of the short-circuiting ring 25 including the shaft hole 25A may be die-casting and casting joining.

In the above embodiment, the rotary shaft 21 is fixed to the rotor core 30 by shrink fitting, but may be fixed by other methods, for example, press fitting.
In the above embodiment, the rotor 20 may be provided with a reinforcing member that prevents the deformation of the short-circuit rings 25 and 26, and the deformation of the short-circuit rings 25 and 26 may be more reliably suppressed.

  The configuration of the above embodiment is merely an example, and the shape, number, and the like may be changed as appropriate. For example, the rotating shaft 21 may be formed in a cylindrical shape in which the first and second large-diameter portions 21A and 21B are not formed, that is, a step portion is not formed. Further, for example, the insertion hole 32 may be configured as a conductor slot that is partially open to the outer peripheral surface of the rotor core 30 (is an open slot). The stator 10 is not limited to being driven by a three-phase alternating current, but may be driven by a single-phase alternating current, a two-phase alternating current, or a multiphase alternating current of four or more phases. Moreover, although the rotor core 30 was formed by laminating electromagnetic steel plates, it may be formed of an iron block or a powder-molded magnetic body (SMC: Soft Magnetic Composites). Moreover, the secondary conductor 23 is not restricted to the structure formed by aluminum die-casting. For example, the pre-formed secondary conductor 23 may be inserted into the insertion hole 32 from the end faces 33 and 34 of the rotor core 30, and the short-circuit ring 25 may be die-cast to the end portion 23 </ b> A of the inserted secondary conductor 23.

  The induction motor 1 is an example of an induction motor, the rotors 20, 100 and 101 are examples of a rotor, the rotary shaft 21 is an example of a rotary shaft, the rotor core 30 is an example of a rotor core, and the secondary conductor 23. As an example of the secondary conductor, the short-circuit rings 25 and 26 are examples of the short-circuit ring, the insertion hole 32 is an example of the conductor slot, and the first to third spray coatings 41 to 43 are examples of the film. The first short-circuit member 110 can be cited as an example of the first short-circuit member, and the second short-circuit member 111 can be cited as an example of the second short-circuit member.

  1 .. Induction motor, 10.. Stator, 20, 100, 101... Rotor, 21... Rotating shaft, 21 C ... Outer peripheral surface, 30 ... Rotor core, 33 ... First end face, 34 ... 2 end faces, 32 .... insertion holes, 23 ... secondary conductors, 25, 26 ... short-circuit rings, 25A ... shaft holes, 41 to 43 ... first to third spray coatings, 110 ... first short circuit Member, 111 .. second short-circuit member.

Claims (9)

A rotor core provided so as to be integrally rotatable with respect to the rotation shaft;
A plurality of secondary conductors inserted through conductor slots provided dispersed in the circumferential direction of the rotor core;
A short-circuit ring that interconnects the ends of the secondary conductors at the end face of the rotor core in the axial direction of the rotating shaft;
A rotor having
The short-circuit ring has a shaft hole through which the rotating shaft is inserted;
The rotary shaft has an insulating first film formed on the outer peripheral surface corresponding to the inner peripheral surface of the shaft hole,
The rotor, wherein an inner peripheral surface of the shaft hole of the short-circuit ring is cast-bonded to the first film. The rotor according to claim 1,
The rotor core is further formed with an insulating second film on the end face corresponding to the short-circuit ring,
The rotor, wherein the short ring is cast-bonded to the second coating. The rotor according to claim 1 or 2,
The rotor core is further formed with an insulating third film on the inner wall of the conductor slot corresponding to the secondary conductor,
The rotor, wherein the secondary conductor is cast-bonded to the third coating. The rotor according to any one of claims 1 to 3,
The rotor according to claim 1, wherein the first to third coatings are made of a ceramic spray material. The rotor according to any one of claims 1 to 4, wherein
The rotor, wherein the short-circuit ring and the secondary conductor are integrally die-cast. The rotor according to any one of claims 1 to 5,
The rotor is characterized in that the short-circuit ring has a substantially disk shape and includes a processed portion from which at least a part thereof is removed.   An induction motor comprising the rotor according to claim 1. A rotor core provided so as to be integrally rotatable with respect to the rotary shaft; a plurality of secondary conductors inserted into conductor slots provided in a distributed manner in the circumferential direction of the rotor core; and an end face of the rotor core in the axial direction of the rotary shaft A short-circuiting ring that interconnects ends of the secondary conductors, and a method of manufacturing a rotor,
Forming an insulating first film on the outer peripheral surface of the rotating shaft corresponding to the inner peripheral surface of the shaft hole of the short-circuit ring through which the rotating shaft is inserted;
Fixing the rotor core to be integrally rotatable with respect to the rotating shaft on which the first film is formed;
A step of casting and joining the inner peripheral surface of the shaft hole of the short-circuit ring to the first film;
A method for manufacturing a rotor, comprising: A rotor core provided so as to be integrally rotatable with respect to the rotary shaft; a plurality of secondary conductors inserted into conductor slots provided in a distributed manner in the circumferential direction of the rotor core; and an end face of the rotor core in the axial direction of the rotary shaft A short-circuiting ring that interconnects ends of the secondary conductors, and a method of manufacturing a rotor,
Fixing the rotor core so as to be integrally rotatable with respect to the rotating shaft;
In the outer peripheral surface of the rotating shaft to which the rotor core is fixed, a first insulating material is provided on the outer peripheral surface of the rotating shaft corresponding to the inner peripheral surface of the shaft hole of the short-circuit ring through which the rotating shaft is inserted. Forming a film;
A step of casting and joining the inner peripheral surface of the shaft hole of the short-circuit ring to the first film;
A method for manufacturing a rotor, comprising:

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