JP2014079114A - Method for manufacturing induction rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form stable weld metal when arc-welding a conductor bar and an end ring.SOLUTION: A method for manufacturing an induction rotary electric machine includes the steps of: assembling a conductor bar 254 and an end ring 226 to a rotor core to form a rotor assembly (assembling step); forming a welding groove over an end surface side of the end ring 226 to an outer peripheral surface side of the end ring 226 in the whole periphery of the end ring 226 while the conductor bar 254 is fitted to the end ring 226 (groove forming step); and performing build-up welding of the welding groove by using arc welding by circulating a torch with respect to the rotor assembly (build-up welding step). The build-up welding step includes the steps of: starting arc discharge between an electrode of a torch 229, and the end ring 226 and the conductor bar 254 to form a molten pool 225 (first step); and circulating the torch 229 while forming an arc between an electrode of the torch 229 and the molten pool 225 so as to prevent the arc discharge from being projected from the molten pool (second step).

Description

  The present invention relates to a method for manufacturing an induction rotating electrical machine.

  As a method for manufacturing a squirrel-cage rotor of an induction rotating electrical machine, a method is known in which a conductor bar is fitted into each of a large number of fitting portions (grooves) provided in an end ring and arc welding is performed. Patent Document 1 discloses a method of manufacturing a squirrel-cage rotor by arc-welding a conductor bar and an end ring while applying rotation to an assembly in which both ends of the conductor bar are fitted in fitting portions of the end ring. It is disclosed.

JP 56-35661 A

  High efficiency is desired in an induction rotating electrical machine for driving an electric vehicle. When arc welding the conductor bar and the end ring, it is desirable to increase the amount of weld overlay and increase the cross-sectional area of the weld metal (weld bead) from the viewpoint of improving the efficiency of the rotating electrical machine.

  However, since a gap exists between the conductor bar and the fitting portion of the end ring, the torch approaches the gap when performing arc welding while rotating the rotor assembly in which the conductor bar is assembled to the end ring. And an arc is generated between the electrode of the torch and the conductor bar (or end ring), and then an arc is generated between the electrode and the end ring (or conductor bar). In some cases, an arc occurs between the conductor bar and the end ring, such as an arc between the end ring and the end ring.

  Patent Document 1 does not disclose a welding method that takes into account the gap between the conductor bar and the fitting portion of the end ring. Therefore, in the welding method of Patent Document 1, the arc becomes unstable, and there is a possibility that a stable weld metal cannot be obtained. As a result, the cross-sectional area of the weld metal in the plane including the rotation center axis of the rotor becomes nonuniform in the circumferential direction of the rotor, and the secondary resistance value becomes high without obtaining a desired cross-sectional area in part. Therefore, there is a problem that it is difficult to increase the efficiency of the induction rotating electrical machine.

The invention according to claim 1 is accommodated in each of a plurality of slots formed in the rotor core, and a plurality of conductor bars whose both ends protrude from the axial end surface of the rotor core, and at both ends of the rotor core. In a method of manufacturing an induction rotating electrical machine comprising: a pair of end rings that are disposed and have end portions of conductor bars protruding from both axial end faces of the rotor core, the end portions of which are fitted; In an assembly process in which a rotor assembly is formed by fitting the end of the conductor bar into the fitting portion of the end ring, and the conductor bar and the end ring are fitted in the slot of the rotor core, In the entire circumference of the end ring, a groove forming step for forming a weld groove from the end face side of the end ring to the outer peripheral face side of the end ring, and by rotating the torch around the rotor assembly, or Rotor assembly Including overlay welding process of forming weld metal that forms a conduction path between the end ring and the conductor bar by overlay welding of the welding groove by arc welding by rotating with respect to the torch. The process includes a first step of starting an arc discharge between the torch electrode and the end ring and the conductor bar to form a molten pool; and the torch electrode and the molten pool so that the arc discharge does not protrude from the molten pool. And a second step of rotating the rotor assembly relative to the torch while forming an arc between them.
According to a second aspect of the present invention, in the manufacturing method of the induction rotating electrical machine according to the first aspect, in the groove forming step, the deepest portion of the weld groove is the outer side in the axial direction of the weld front end portion on the outer peripheral surface side of the end ring. And a welding groove is formed so that it may be located in the diameter direction outside of the welding opening front-end | tip part in the end surface side of an end ring.
According to a third aspect of the present invention, in the method for manufacturing an induction rotating electrical machine according to the first or second aspect, in the build-up welding process, the cross-sectional area of the weld metal in a plane including the rotation center axis of the rotor is the rotation center. The weld metal is formed so as to be larger than the cross-sectional area of the conductor bar in a plane orthogonal to the axis.
The invention according to claim 4 is accommodated in each of a plurality of slots formed in the rotor core, and a plurality of conductor bars whose both ends protrude from the axial end surface of the rotor core, and at both ends of the rotor core. In a method of manufacturing an induction rotating electrical machine comprising: a pair of end rings that are disposed and have end portions of conductor bars protruding from both axial end faces of the rotor core, the end portions of which are fitted; In an assembly process in which a rotor assembly is formed by fitting the end of the conductor bar into the fitting portion of the end ring, and the conductor bar and the end ring are fitted in the slot of the rotor core, In the entire circumference of the end ring, a groove forming process for forming a weld groove from the end face side of the end ring to the outer peripheral face side of the end ring, and by rotating the torch around the rotor assembly a plurality of times, Or the rotor By overlaying the welding groove by arc welding by rotating the solid body multiple times with respect to the torch, the overlay is formed by forming a weld metal that constitutes a conduction path between the end ring and the conductor bar by a plurality of overlay layers. A method of manufacturing an induction rotating electrical machine including a welding step, wherein a gap between a conductor bar and a fitting portion of an end ring is covered with a first overlay layer in the overlay welding step is there.
According to a fifth aspect of the present invention, in the method for manufacturing an induction rotating electrical machine according to the fourth aspect, in the build-up welding step, the build-up amount for forming the first build-up layer is changed to the second layer build-up amount. It is characterized by being less than the amount of overlay for forming the subsequent overlay layer.
The invention according to claim 6 is the method of manufacturing an induction rotating electrical machine according to claim 4 or 5, wherein in the groove forming step, the deepest portion of the weld groove is the axis of the weld opening tip portion on the outer peripheral surface side of the end ring. The welding groove is formed so as to be located on the outer side in the direction and on the outer side in the radial direction of the weld opening tip on the end face side of the end ring.
The invention according to claim 7 is the method of manufacturing an induction rotating electrical machine according to any one of claims 4 to 6, wherein the weld metal is cut off in a plane including the rotation center axis of the rotor in the overlay welding process. The weld metal is formed so that the area is larger than the cross-sectional area of the conductor bar in a plane orthogonal to the rotation center axis.

  According to the present invention, when arc welding the conductor bar and the end ring, a stable weld metal can be formed, so that the induction rotating electrical machine can be highly efficient.

The figure which shows schematic structure of the hybrid electric vehicle carrying the rotary electric machine which concerns on embodiment of this invention. The circuit diagram which shows the power converter device of FIG. The half sectional view showing the rotary electric machine concerning an embodiment of the invention. FIG. 4 is an external perspective view of the rotor of FIG. 3. The disassembled perspective view of the rotor of FIG. The partial expansion side surface schematic diagram which looked at the rotor of FIG. 4 from the axial direction. Sectional drawing of a conductor bar. The external appearance perspective view which shows the rotor assembly which assembled | attached the conductor bar and the end ring to the rotor core. The external appearance perspective view which shows the rotor assembly in which the welding groove | channel was formed. 10A is an enlarged view of a portion B in FIG. 9, and FIG. 10B is a cross-sectional view taken along the line CC in FIG. 10A. FIG. 11A illustrates a molten pool forming process for forming a molten pool, and FIG. 11B illustrates a torch rotating process for rotating the torch while forming an arc between the electrode of the torch and the molten pool. To do. 12A is an enlarged view of a portion A in FIG. 4, and FIG. 12B is a cross-sectional view taken along line FF in FIG. The figure which shows the comparative example of FIG.10 (b). 14A is a diagram showing a comparative example of FIG. 10B, and FIG. 14B is a diagram showing a comparative example of FIG. 12B. Fig.15 (a) is a perspective view which shows the 1st layer weld metal (facing layer), FIG.15 (b) is the DD sectional view taken on the line of Fig.15 (a). 16A is an enlarged view of a portion A in FIG. 4, and FIG. 16B is a cross-sectional view taken along the line EE in FIG. The partial expanded sectional view which shows the groove shape of the rotor in the rotary electric machine which concerns on the modification of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
An induction rotating electrical machine (hereinafter simply referred to as a rotating electrical machine) manufactured by the manufacturing method according to the present invention is a pure electric vehicle that runs only by the rotating electrical machine, a hybrid electric vehicle that is driven by both the engine and the rotating electrical machine, or the like. Applicable. Below, the example applied to the hybrid electric vehicle is demonstrated.

-First embodiment-
As shown in FIG. 1, a hybrid electric vehicle (hereinafter referred to as a vehicle) 100 is equipped with an engine 120, a first rotating electrical machine 200, a second rotating electrical machine 202, and a high-voltage battery 180. .

  The battery 180 is composed of a secondary battery such as a lithium ion battery or a nickel metal hydride battery, and outputs high-voltage DC power of 250 to 600 volts or more. The battery 180 supplies DC power to the rotating electrical machines 200 and 202 during power running, and DC power is supplied from the rotating electrical machines 200 and 202 to the battery 180 during regenerative traveling. Transfer of direct-current power between the battery 180 and the rotating electrical machines 200 and 202 is performed via the power converter 600.

  The vehicle 100 is equipped with a battery (not shown) that supplies low voltage power (for example, 14 volt system power), and supplies DC power to a control circuit described below.

  Rotational torque generated by engine 120 and rotating electrical machines 200 and 202 is transmitted to front wheel 110 via transmission 130 and differential gear 160. Transmission 130 is controlled by transmission control device 134, engine 120 is controlled by engine control device 124, and charging / discharging of battery 180 is controlled by battery control device 184.

  An integrated control device 170 is connected to the transmission control device 134, the engine control device 124, the battery control device 184, and the power conversion device 600 via a communication line 174.

  The integrated control device 170 manages the output torque of the engine 120 and the rotating electric machines 200 and 202, calculates the total torque of the output torque of the engine 120 and the output torque of the rotating electric machines 200 and 202, and the torque distribution ratio, and the calculation processing result. The control command is transmitted to the transmission control device 134, the engine control device 124, and the power conversion device 600 based on the above.

  Therefore, information representing the respective states is input to the integrated control device 170 from the transmission control device 134, the engine control device 124, the power conversion device 600, and the battery control device 184 via the communication line 174. These control devices are lower-level control devices than the integrated control device 170. The integrated control device 170 calculates a control command for each control device based on these pieces of information. The calculated control command is transmitted to each control device via the communication line 174.

  The battery control device 184 outputs the charge / discharge status of the battery 180 and the state of each unit cell battery constituting the battery 180 to the integrated control device 170 via the communication line 174. The integrated control device 170 controls the power conversion device 600 based on the information from the battery control device 184, and when it determines that the battery 180 needs to be charged, issues an instruction for power generation operation to the power conversion device 600.

  Based on the torque command from the integrated control device 170, the power conversion device 600 controls the rotating electrical machines 200 and 202 so that torque output or generated power is generated as commanded. Therefore, the power conversion device 600 is provided with a power semiconductor that constitutes an inverter. The power conversion device 600 controls the switching operation of the power semiconductor based on a command from the integrated control device 170. By such a power semiconductor switching operation, the rotating electrical machines 200 and 202 are operated as an electric motor or a generator.

  When the rotary electric machines 200 and 202 are operated as an electric motor, DC power from the high-voltage battery 180 is supplied to the DC terminal of the inverter of the power conversion device 600. The power converter 600 converts the supplied DC power into three-phase AC power by controlling the switching operation of the power semiconductor, and supplies the three-phase AC power to the rotating electrical machines 200 and 202.

  On the other hand, when the rotary electric machines 200 and 202 are operated as a generator, the rotor is rotationally driven with a rotational torque applied from the outside, and three-phase AC power is generated in the stator winding. The generated three-phase AC power is converted into DC power by the power converter 600, and charging is performed by supplying the DC power to the high-voltage battery 180.

  As shown in FIG. 2, the power conversion device 600 is provided with a first inverter device for the first rotating electrical machine 200 and a second inverter device for the second rotating electrical machine 202. . The first inverter device includes a power module 610, a first drive circuit 652 that controls the switching operation of each power semiconductor element 21 of the power module 610, and a current sensor 660 that detects the current of the rotating electrical machine 200. Yes. The drive circuit 652 is provided on the drive circuit board 650.

  The second inverter device includes a power module 620, a second drive circuit 656 that controls the switching operation of each power semiconductor element 21 in the power module 620, and a current sensor 662 that detects the current of the rotating electrical machine 202. Yes. The drive circuit 656 is provided on the drive circuit board 654.

  The current sensors 660 and 662 and the drive circuits 652 and 656 are connected to a control circuit 648 provided on the control circuit board 646, and further, a communication line 174 via a transmission / reception circuit 644 is connected to the control circuit 648. . The transmission / reception circuit 644 is provided on the transmission / reception circuit board 642 and is used in common by the first and second inverter devices. The transmission / reception circuit 644 is for electrically connecting the power conversion apparatus 600 and an external control apparatus, and transmits / receives information to / from other apparatuses via the communication line 174 in FIG.

  The control circuit 648 constitutes a control unit of each inverter device, and is constituted by a microcomputer that calculates a control signal (control value) for operating (turning on / off) the power semiconductor element 21. The control circuit 648 includes a torque command signal (torque command value) from the integrated control device 170, sensor outputs of the current sensors 660 and 662, rotation sensors mounted on the rotating electrical machines 200 and 202, that is, a resolver 224 (see FIG. 3). Sensor output is input. The control circuit 648 calculates a control value based on these input signals and outputs a control signal for controlling the switching timing to the drive circuits 652 and 656.

  Each of the drive circuits 652 and 656 is provided with six integrated circuits that generate drive signals to be supplied to the gates of the upper and lower arms of each phase, and the six integrated circuits are configured as one block. The drive signals generated by the drive circuits 652 and 656 are output to the gates of the power semiconductor elements 21 of the corresponding power modules 610 and 620, respectively.

  A capacitor module 630 is electrically connected in parallel to the DC side terminals of the power modules 610 and 620, and the capacitor module 630 is a smoothing circuit for suppressing fluctuations in DC voltage caused by the switching operation of the power semiconductor element 21. Configure. The capacitor module 630 is commonly used in the first and second inverter devices.

  Each of the power modules 610 and 620 converts DC power supplied from the battery 180 into three-phase AC power and supplies the power to stator windings that are armature windings of the corresponding rotating electric machines 200 and 202. The power modules 610 and 620 convert the alternating current power induced in the stator windings of the rotating electric machines 200 and 202 into direct current and supply the direct current to the high voltage battery 180.

  The power modules 610 and 620 include a three-phase bridge circuit as shown in FIG. 2, and series circuits corresponding to the three phases are electrically connected in parallel between the positive electrode side and the negative electrode side of the battery 180, respectively. ing. Each series circuit includes a power semiconductor element 21 constituting an upper arm and a power semiconductor element 21 constituting a lower arm, and these power semiconductor elements 21 are connected in series.

  The power module 610 and the power module 620 are configured in substantially the same manner, and here, the power module 610 will be described as a representative.

  The power module 610 uses an IGBT (insulated gate bipolar transistor) as a switching power semiconductor element. The IGBT includes three electrodes, a collector electrode, an emitter electrode, and a gate electrode. A diode 38 is electrically connected between the collector electrode and the emitter electrode of the IGBT. The diode 38 includes two electrodes, a cathode electrode and an anode electrode. The cathode electrode is the IGBT collector electrode and the anode electrode is the IGBT so that the direction from the emitter electrode to the collector electrode of the IGBT is the forward direction. Each is electrically connected to the emitter electrode.

The arm of each phase is configured by electrically connecting an IGBT emitter electrode and an IGBT collector electrode in series.
In FIG. 2, only one IGBT for each upper and lower arm of each phase is shown, but since the current capacity to be controlled is large, actually, a plurality of IGBTs are electrically connected in parallel. Yes.

  The collector electrode of the IGBT of each upper arm of each phase is electrically connected to the positive electrode side of the battery 180, and the emitter electrode of the IGBT of each lower arm of each phase is electrically connected to the negative electrode side of the battery 180. The middle point of each arm of each phase (the connection portion between the emitter electrode of the upper arm side IGBT and the collector electrode of the IGBT on the lower arm side) is the armature winding (fixed) of the corresponding phase of the corresponding rotating electric machine 200, 202. Is electrically connected to the secondary winding.

  Since the rotating electrical machines 200 and 202 are configured in substantially the same manner, the rotating electrical machine 200 will be described below as a representative.

  As shown in FIG. 3, the rotating electrical machine 200 includes a housing 212 and a stator 230 held inside the housing 212, and the stator 230 includes a stator core 232 and a stator winding 238. . Inside the stator core 232, a rotor 250 is rotatably held through a gap 222. In other words, the stator core 232 is disposed with a gap 222 on the outer peripheral side of the rotor 250. The rotor 250 includes a rotor core 252, a conductor bar 254, and an end ring 226, and the rotor core 252 is fixed to a columnar shaft (rotary shaft body) 218.

  The housing 212 has a pair of end brackets 214 provided with bearings 216, and the shaft 218 is rotatably held by these bearings 216. The shaft 218 is provided with a resolver 224 that detects the rotational position and rotational speed of the rotor 250, and the output of the resolver 224 is input to the control circuit 648 shown in FIG.

  Referring to FIG. 2, the control circuit 648 controls the drive circuit 652 based on the output of the resolver 224. The drive circuit 652 performs a switching operation of the power module 610 to convert the DC power supplied from the battery 180 into three-phase AC power. Similarly, the control circuit 648 switches the power module 620 via the drive circuit 656, and converts the DC power supplied from the battery 180 into three-phase AC power. This three-phase AC power is supplied to the stator winding 238, and a rotating magnetic field is generated in the stator 230. The frequency of the three-phase alternating current is controlled based on the detected value of the resolver 224, and the phase of the three-phase alternating current with respect to the rotor 250 is also controlled based on the detected value of the resolver 224. AC power is supplied.

  As shown in FIG. 3, the stator 230 includes a cylindrical stator core 232 and a stator winding 238 that is inserted into the stator core 232. The stator core 232 is formed by stacking a plurality of annular magnetic steel sheets. The magnetic steel sheet constituting the stator core 232 has a thickness of about 0.05 to 1.0 mm and is formed by punching or etching.

  The stator core 232 is formed by laminating electromagnetic steel plates so that a plurality of slots (not shown) extending in the axial direction of the stator core 232 are equally spaced in the circumferential direction. The slot is provided with insulating paper (not shown) corresponding to the slot shape, and accommodates U, V, W phase windings constituting the stator winding 238. The teeth formed between the slots guide the rotating magnetic field generated by the stator winding 238 to the rotor 250 and cause the rotor 250 to generate rotational torque.

  In the present embodiment, distributed winding is adopted as a method of winding the stator winding 238. The distributed winding is a winding method in which the phase winding is wound around the stator core 232 so that the phase winding of each phase is accommodated in two slots that are spaced apart from each other across a plurality of slots.

  4 and 5 are an external perspective view and an exploded perspective view of the rotor 250, respectively. FIG. 6 is a partially enlarged side schematic view of the rotor 250 of FIG. 4 viewed from the axial direction. 4 to 6, illustration of the shaft 218 is omitted. As shown in FIGS. 4 and 5, the rotor 250 according to the present embodiment has a large number of conductor bars 254 and a pair of end rings 226 assembled to the rotor core 252, and both axial ends of the rotor 250. This is an assembly type squirrel-cage rotor in which the end ring 226 and the conductor bar 254 are joined by arc welding such as TIG welding or MIG welding. The welding method will be described later.

  As shown in FIGS. 4 and 5, the rotor 250 is inserted into a cylindrical rotor core 252 having a through hole 251 through which the shaft 218 (see FIG. 3) is inserted, and a slot 252 b of the rotor core 252. And a pair of end rings 226 disposed at both ends of the rotor core 252 and electrically connected to the conductor bar 254 by arc welding.

  The rotor core 252 is formed by laminating a plurality of annular electromagnetic steel plates. The electrical steel sheet constituting the rotor core 252 has a thickness of about 0.05 to 1.0 mm and is formed by punching or etching. In the rotor core 252, a plurality of teeth 252a and slots 252b parallel to the axial direction are formed at equal intervals in the circumferential direction.

  The width (circumferential length) of the teeth 252a of the rotor core 252 is a substantially constant width from the rotation center side (root portion) toward the radially outer side. As a result, the width of the slot 252b defined by the adjacent teeth 252a is maximum on the outer peripheral side (opening side), gradually decreases from the outer peripheral side toward the radial inner side, and is minimum on the rotation center side. It has become.

  In each slot 252 b extending in the axial direction of the rotor 250, a long plate-like conductor bar 254 is accommodated, and both ends of the conductor bar 254 in the longitudinal direction are disposed at both ends of the rotor core 252. The end ring 226 is fitted.

  The conductor bar 254 is a long flat plate member made of a metal material having a low electrical resistivity such as copper or aluminum and extending in the axial direction of the rotor 250. As shown in FIGS. 5 and 6, the conductor bar 254 has substantially the same outer shape as the slot 252b of the rotor core 252 and is accommodated in the slot 252b. As shown in FIG. 7, the conductor bar 254 has a tapered shape in which a cross-sectional shape in a plane orthogonal to the rotation center axis of the rotor 250 gradually decreases from the outer peripheral side to the center side of the rotor 250. Has been.

  As shown in FIG. 4, the conductor bar 254 is formed longer than the axial length of the rotor core 252, and both end portions of the conductor bar 254 protrude outward from the axial end surface of the rotor core 252. Yes.

  The pair of end rings 226 are made of the same kind of metal as the conductor bar 254 and are disposed at both ends of the rotor core 252. As shown in FIGS. 4 to 6, each end ring 226 has a plurality of fitting portions 227 into which the end portions of the conductor bars 254 protruding from the axial end surface of the rotor core 252 are fitted. As shown in FIGS. 5 and 6, a plurality of fitting portions 227 are formed so as to be equidistant in the circumferential direction corresponding to the slots 252 b of the rotor core 252. Each fitting portion 227 is a through hole that is parallel to the axial direction and is formed in a groove shape that is open on the outer peripheral side.

  As shown in FIG. 7, the fitting portion 227 of the end ring 226 has substantially the same cross-sectional shape as the conductor bar 254, and the circumference of the fitting portion 227 (opening) is larger than the circumferential dimension of the conductor bar 254. The directional dimension is formed to be slightly larger. As shown in FIG. 7, when the conductor bar 254 is accommodated in the fitting portion 227 of the end ring 226, a gap 228 is formed between the flat portion 254 </ b> P of the conductor bar 254 and the inner side surface of the fitting portion 227. The

  When the end of the conductor bar 254 in the longitudinal direction is fitted to each fitting portion 227 of each end ring 226 and the conductor bar 254 is joined to the end ring 226 by arc welding, when viewed from the axial direction, An annular weld metal (joint) 220 is formed (see FIGS. 4 and 6).

  A method for manufacturing the rotary electric machine 200 according to the first embodiment will be described in detail. 8 is an external perspective view showing a rotor assembly 250A in which the conductor bar 254 and the end ring 226 are assembled to the rotor core 252. FIG. 9 is an external perspective view showing the rotor assembly 250A in which a weld groove is formed. FIG. FIG. 10A is an enlarged view of a portion B in FIG. 9, and FIG. 10B is a cross-sectional view taken along the line CC in FIG. As shown in FIG. 10B, the axial direction of the rotor 250 is defined as the x direction, and the radial direction of the rotor 250 is defined as the y direction. FIG. 11A is a perspective view showing the first overlay layer 220A (welded metal), and FIG. 11B is a cross-sectional view taken along the line DD in FIG. 11A.

-Preparation process-
As shown in FIG. 5, a rotor core 252, a plurality of conductor bars 254, and a pair of end rings 226 are prepared.

-Assembly process-
As shown in FIG. 8, the conductor bar 254 is accommodated in the slot 252b of the rotor core 252, and both ends of the conductor bar 254 are fitted to the fitting portions 227 provided in the pair of end rings 226, respectively. A child assembly 250A is formed.

  As shown in FIG. 7, the conductor bar 254 is fitted into the fitting portion 227 of the end ring 226. At this time, a gap 228 is formed between the flat portion 254P of the conductor bar 254 and the inner side surface of the fitting portion 227.

-Groove formation process-
As shown in FIG. 9 and FIG. 10A, a welding groove is formed by cutting out the conductor bar 254 and the end ring 226 in a state where the conductor bar 254 and the end ring 226 are fitted. The weld groove is formed into a curved concave shape by cutting out from the end surface 226a side of the end ring 226 to the outer peripheral surface 226b side of the end ring 226 on the entire circumference of the end ring 226.

  As shown in FIG. 10B, the weld groove is a welded open front end where the cross-sectional shape in the plane including the rotation center axis of the rotor 250 corresponds to the end of the end face 226 a of the end ring 226. 300a and the welded open end 300b, which is a position corresponding to the end of the outer peripheral surface 226b of the end ring 226, are connected by an arcuate curve.

  In the groove forming step described above, as shown in FIG. 10B, the deepest portion DP of the weld groove is on the outer side in the x direction (axial direction) of the weld opening tip 300b on the outer peripheral surface 226b side of the end ring 226. In addition, the welding groove is formed so as to be positioned on the outer side in the y direction (radial direction) of the weld opening tip portion 300a on the end surface 226a side of the end ring 226.

  The deepest portion DP of the welding groove is a normal direction distance m with respect to the line segment A between the line segment A connecting the weld opening tip part 300a and the welding opening tip part 300b and the curve B constituting the groove surface GF. Is defined as the position where is the maximum.

-Overlay welding process-
As shown in FIG. 9, the weld groove is build-up welded by rotating the torch 229 around the weld groove surface GF one or more times with respect to the rotor assembly 250 </ b> A, and the end ring 226, the conductor bar 254, A weld metal 220 (weld bead) that forms a conduction path is formed (see FIG. 4). In the present embodiment, a welding machine (not shown) having a wire feeding device capable of automatically and continuously feeding a welding wire (not shown) to the torch 229 is used, and an electrode (welding wire) of the torch 229 and An arc was generated between the workpiece and the workpiece, and the end ring 226 and the conductor bar 254 were gas shielded arc welded. In the first embodiment, as described below, a molten pool formation process and a torch circulation process are included. A specific overlay welding process will be described below.

  FIG. 11A is a diagram for explaining a molten pool forming process for forming the molten pool 225, and FIG. 11B is a circuit around the torch 229 while forming an arc between the electrode of the torch 229 and the molten pool 225. It is a figure explaining the torch turning process to be performed. In FIG. 11A, the initial molten pool 225i that is initially formed by forming an arc between the electrode of the torch 229 and the arc discharge region 221 on the end ring 226 and the conductor bar 254 is indicated by hatching. . In FIG. 11A, the manner in which the molten pool 225 expands is conceptually indicated by a dashed arrow. In FIG. 11 (b), the arc discharge region 221 and the molten pool 225 on the molten pool 225 that have moved in accordance with the movement of the moved torch 229 and the torch 229 are indicated by two-dot chain lines. 12A is an enlarged view of a portion A in FIG. 4, and FIG. 12B is a cross-sectional view taken along line FF in FIG.

-Molten pool formation process-
As shown in FIG. 11A, the torch 229 is fixed, and arc discharge (not shown) is performed between the electrode of the torch 229 and the arc discharge region 221 on the end ring 226 and the conductor bar 254 at a predetermined position. The initial molten pool 225i is formed by starting. Here, the arc discharge region is a region on the work piece that generates an arc between the electrodes of the torch 229.

  As shown in FIG. 11A, the molten pool 225 is expanded to a region wider than the arc discharge region 221 by forming an arc mainly between the electrode of the torch 229 and the initial molten pool 225 i. By sufficiently expanding the molten pool 225, the arc discharge region 221 can be formed only on the molten pool 225. In this state, arc discharge does not protrude from the molten pool 225.

-Torch circulation process-
As shown in FIG. 11B, the torch 229 is circulated while forming an arc between the electrode of the torch 229 and the molten pool 225 so that the arc discharge region 221 does not protrude from the molten pool 225. When rotating, the welding wire feeding speed and the rotating speed of the torch 229 are adjusted so that the arc discharge region 221 does not protrude from the molten pool 225. Since the arc discharge does not protrude from the molten pool 225 during the circulation, a stable arc can be maintained.

  The gap 228 (see FIG. 10A) between the conductor bar 254 and the fitting portion 227 of the end ring 226 is covered in advance by the molten pool 225, and the arc melts with the electrode of the torch 229 during the circulation of the torch 229. Occurs with the pond 225. In other words, an arc is prevented from being generated between the electrode of the torch 229 and the end ring 226 or the conductor bar 254 during the rotation of the torch 229.

  In the torch circulation process, since the gap 228 between the conductor bar 254 and the fitting portion 227 of the end ring 226 is already covered by the molten pool 225, an arc can be generated stably. As a result, the cross-sectional area of the built-up layer 220 in the plane including the rotation center axis of the rotor 250 becomes substantially uniform in the circumferential direction.

  In the overlay welding process described above, the cross-sectional area Sw (see FIG. 12B) of the weld metal 220 in the plane including the rotation center axis of the rotor 250 is in the plane orthogonal to the rotation center axis of the rotor 250. The weld metal 220 is formed so as to be larger than the cross-sectional area Sb (see FIG. 7) of the conductor bar 254.

-Assembly process-
A stator 230 in which a stator winding 238 is mounted on the stator core 232 is fixed to the housing 212 by shrink fitting or press fitting. The shaft 218 of the rotor 250 is attached to the bearing 216 of the one end bracket 214, and the one end bracket 214 is attached to the housing 212 so that the rotor 250 is disposed inside the stator 230. The rotary electric machine 200 is completed by attaching the shaft 218 of the rotor 250 to the bearing 216 of the other end bracket 214 and attaching the other end bracket 214 to the housing 212.

According to 1st Embodiment described above, there can exist the following effects.
(1) When the conductor bar 254 and the end ring 226 are assembled to the rotor core 252 and the conductor bar 254 and the end ring 226 are fitted, the end ring 226 has an entire circumference from the end surface 226a side of the end ring 226. A weld groove is formed over the outer peripheral surface 226b side of the end ring 226, and the torch 229 is turned around the rotor assembly 250A, so that the weld groove is welded by arc welding, and the end ring 226 is welded. The weld metal 220 constituting the conduction path between the conductor bar 254 and the conductor bar 254 was formed. In the overlay welding process, the molten pool 225 was expanded until it became a region wider than the arc discharge region 221, and the torch 229 was rotated so that the arc discharge region 221 did not protrude from the molten pool 225. Since the gap 228 between the conductor bar 254 and the fitting portion 227 is covered in advance by the molten pool 225, it is possible to prevent the arc from becoming unstable when the torch 229 is rotated.

  As a result, a stable weld metal 220 can be formed, and a desired cross-sectional area can be ensured over the entire circumference of the weld metal 220, so that the efficiency of the rotating electrical machine 200 can be increased. Furthermore, a good bead appearance can be obtained.

  On the other hand, if the torch 229 is turned around without considering the relationship between the molten pool 225 and the arc discharge region 221, the arc discharge region 221 protrudes from the molten pool 225 and the arc becomes unstable, and the rotor The entire cross section of the weld metal 220 in the plane including the rotation center axis 250 may be greatly uneven in the circumferential direction, and a desired cross sectional area may not be obtained.

(2) As shown in FIG. 10, in the state where the conductor bar 254 and the end ring 226 are fitted, the end ring 226 has an entire circumference from the end face 226a side of the end ring 226 to the outer peripheral face 226b side of the end ring 226. A weld groove having a curved concave shape was formed. Accordingly, for example, as shown in FIG. 13, the cross-sectional area of the weld metal 220 in the plane including the rotation center axis of the rotor is larger than that in the case where planar weld grooves are formed on the conductor bar 954 and the end ring 926. Can be widened.

(3) The cross section Sw of the weld metal 220 in the plane including the rotation center axis of the rotor 250 (see FIG. 12B) is the break of the conductor bar 254 in the plane orthogonal to the rotation center axis of the rotor 250. Since the weld metal 220 is formed so as to be larger than the area Sb (see FIG. 7), the secondary resistance value can be lowered as compared with the case where the cross-sectional area Sw is smaller than the cross-sectional area Sb. That is, according to the present embodiment, the efficiency of rotating electric machine 200 can be improved.

(4) As shown in FIG. 10B, the deepest portion DP of the weld groove is outside the weld opening tip portion 300b on the outer peripheral surface 226b side of the end ring 226 in the x direction (axial direction), and the end. Since the welding groove is formed so as to be located on the outer side in the y direction (radial direction) of the weld opening tip portion 300a on the end surface 226a side of the ring 226, occurrence of poor penetration can be suppressed. As a result, it is possible to prevent a decrease in strength against the rotational centrifugal force generated when the rotor 250 is rotationally driven.

  On the other hand, as shown in FIG. 14A, the deepest portion DP0 of the weld groove is the inner side in the axial direction of the weld opening tip 300b on the outer peripheral surface 226b side of the end ring 226, and the end ring 226 If the welding groove is formed so as to be located on the inner side in the radial direction of the weld opening tip portion 300a on the end face 226a side, a poor penetration may occur as shown in FIG. 14B. If the cavity portion 900 is formed due to poor penetration, the strength against the rotational centrifugal force may decrease due to stress concentration in the cavity portion 900.

-Second embodiment-
A method for manufacturing the induction rotating electrical machine according to the second embodiment will be described with reference to the drawings. FIG. 15A is a perspective view showing the first build-up layer 220A (welded metal), and FIG. 15B is a cross-sectional view taken along the line DD in FIG. 15A. 16A is an enlarged view of a portion A in FIG. 4, and FIG. 16B is a cross-sectional view taken along the line EE in FIG. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described.

  In the second embodiment, in the build-up welding process, the weld groove is built-up welded by causing the torch 229 to make two turns along the weld groove surface GF with respect to the rotor assembly 250A. A weld metal 220 (weld bead) that forms a conduction path between the end ring 226 and the conductor bar 254 is formed by the overlaying layer (see FIG. 4).

  In the second embodiment, only the build-up welding process is different from the first embodiment described above, and the preparation process, assembly process, groove forming process, and assembly process, which are other processes, are the same as those in the first embodiment. Since it is the same process as the embodiment and the configuration of the rotating electrical machine is the same as that of the first embodiment, only the overlay welding process will be described in detail.

  In the second embodiment, similarly to the first embodiment, a welding machine (not shown) including a wire feeding device capable of automatically and continuously feeding a welding wire (not shown) to the torch 229 is provided. The arc was generated between the electrode (welding wire) of the torch 229 and the work piece, and the end ring 226 and the conductor bar 254 were gas shielded arc welded. A specific overlay welding process will be described below.

  As shown in FIG. 9, by making the torch 229 make one turn with respect to the rotor assembly 250A, as shown in FIG. 15, the first build-up layer 220A is formed thin. A gap 228 (see FIG. 10A) between the conductor bar 254 and the fitting portion 227 of the end ring 226 is covered with the first overlay layer 220A. In the welding work for the first round, since a gap 228 exists between the conductor bar 254 and the fitting portion 227 of the end ring 226 (see FIG. 10A), the arc becomes unstable during the welding work. As a result, the cross-sectional area of the first build-up layer 220A may become uneven in the circumferential direction.

  After the first build-up layer 220A is formed, the torch 229 is further rotated once with respect to the rotor assembly 250A to form the second build-up layer 220B as shown in FIG. To do. At the time of the second round welding operation, the gap 228 between the conductor bar 254 and the fitting portion 227 of the end ring 226 is already covered, so that an arc can be generated stably. As a result, the cross-sectional area of the second build-up layer 220B in the plane including the rotation center axis of the rotor 250 becomes substantially uniform in the circumferential direction.

  In the build-up welding process described above, the build-up amount for forming the first build-up layer 220A was made smaller than the build-up amount for forming the second build-up layer 220B. In other words, the cross-sectional area Sw2 of the second built-up layer 220B shown in FIG. 16B is different from the cross-sectional area Sw1 of the first built-up layer 220A shown in FIG. Was adjusted so that the feeding speed of the welding wire and the rotating speed of the torch 229 were increased.

  In the overlay welding process described above, the cross-sectional area Sw = Sw1 + Sw2 (see FIG. 16B) of the weld metal 220 in the plane including the rotation center axis of the rotor 250 is a plane orthogonal to the rotation center axis of the rotor 250. The weld metal 220 is formed so as to be larger than the cross-sectional area Sb (see FIG. 7) of the conductor bar 254 inside.

  As described above, in the second embodiment, the torch 229 is rotated twice with respect to the rotor assembly 250A, so that the welding groove is welded by arc welding, and the end ring 226 and the conductor bar 254 are connected. A weld metal 220 constituting a conduction path was formed. Since the gap 228 between the conductor bar 254 and the fitting portion 227 of the end ring 226 is covered by the first build-up layer 220A, when forming the second build-up layer 220B, It is possible to prevent the arc from becoming unstable.

  The first build-up layer 220 </ b> A is formed between the conductor bar 254 and the fitting portion 227 in order to prevent the arc from becoming unstable when forming the second build-up layer 220 </ b> B. What is necessary is just to be able to ensure the amount of overlaying which can cover the gap 228 between them.

  In the build-up welding process, the build-up amount for forming the first build-up layer 220A is less than the build-up amount for forming the second build-up layer 220B. The ratio of the non-uniform cross-sectional area due to the instability of the arc can be reduced with respect to the entire cross section of the weld metal 220 in the plane including the rotation center axis of the child 250. Furthermore, when the second build-up layer 220B is formed, non-uniformity in the cross-sectional area of the first build-up layer 220A is improved by welding heat input.

  That is, according to the second embodiment, a stable weld metal 220 can be formed as in the effect (1) described in the first embodiment, and the entire circumference of the weld metal 220 can be formed. Since a desired cross-sectional area can be ensured, high efficiency of the rotating electrical machine 200 can be achieved. Furthermore, a good bead appearance can be obtained.

  Furthermore, according to 2nd Embodiment, there exists an effect similar to (2)-(4) demonstrated in 1st Embodiment.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(1) In the first and second embodiments described above, the weld groove is formed in an arc shape when viewed from a direction orthogonal to the rotation center axis, but the present invention is not limited to this. As shown in FIG. 17, when viewed from a direction orthogonal to the rotation center axis, a plurality of straight lines 301 a, 301 b, 301 c may be processed to form a welding groove.

(2) In the first embodiment described above, the end groove 226 and the conductor are welded by arc welding the welding groove by rotating the torch 229 around the rotor assembly 250A one or more times. Although the weld metal 220 forming the conduction path with the bar 254 is formed, the present invention is not limited to this. The weld metal 220 may be formed by rotating the torch 229 around the rotor assembly 250A two or more times. In the case of two or more turns, the torch 229 may be turned so that the arc discharge region 221 does not protrude from the molten pool 225 during the first turn.

(3) In the second embodiment described above, the end ring 226 and the conductor bar 254 are welded by arc welding of the welding groove by turning the torch 229 twice with respect to the rotor assembly 250A. However, the present invention is not limited to this. The weld metal 220 may be formed by rotating the torch 229 around the rotor assembly 250A three or more times. In this case, it is sufficient that the first overlay layer has a sufficient amount of overlay so as to cover at least the gap 228 between the fitting portion 227 of the end ring 226 and the conductor bar 254. It is preferable that the amount of overlay for forming the build-up layer is less than the amount of build-up for forming the build-up layers for the second and subsequent layers.

(4) The present invention is not limited to the case where the torch 229 rotates around the rotor assembly 250A, but the torch 229 is fixed and the rotor assembly 250A is rotated relative to the torch 229. Thus, the weld metal 220 may be formed.

(5) In the above embodiment, the method of arc welding by a welding machine (not shown) provided with a wire feeding device capable of automatically and continuously feeding a welding wire (not shown) to the torch 229 has been described. However, the present invention is not limited to this. Arc welding may be performed by manual welding. In addition to automatically feeding the wire, arc welding may be performed by a fully automatic welding machine (not shown) provided with a rotating device (not shown) that automatically rotates the torch 229 or the rotor assembly 250A.

(6) The rotating electrical machines 200 and 202 may be used for other electric vehicles, for example, railway vehicles such as hybrid trains, passenger cars such as buses, cargo vehicles such as trucks, industrial vehicles such as battery-type forklift trucks, and the like. it can.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

  200,202 Rotating electric machine, 212 Housing, 214 End bracket, 216 Bearing, 218 shaft, 220 Weld metal, 220A, 220B Overlay layer, 221 Arc discharge area, 222 Clearance, 225 Weld pool, 226 End ring, 226a End face, 226b Outer peripheral surface, 227 fitting portion, 228 clearance, 229 torch, 230 stator, 232 stator core, 238 stator winding, 250 rotor, 250A rotor assembly, 251 through hole, 252 rotor core, 252a teeth , 252b slot, 254 conductor bar, 300a, 300b weld open tip, 301a-301c straight line

Claims (7)

A plurality of conductor bars which are housed in each of a plurality of slots formed in the rotor core and whose both end portions protrude from an axial end surface of the rotor core, and are disposed at both ends of the rotor core; In a method of manufacturing an induction rotating electrical machine including a pair of end rings having fitting portions into which ends of conductor bars protruding from both axial end faces of the iron core are fitted,
An assembly step in which the conductor bar is accommodated in a slot of the rotor core, and an end portion of the conductor bar is fitted into a fitting portion of the end ring to form a rotor assembly;
A groove forming step of forming a welding groove from the end face side of the end ring to the outer peripheral face side of the end ring in the entire circumference of the end ring in a state where the conductor bar and the end ring are fitted. When,
By welding the weld groove by arc welding by rotating a torch around the rotor assembly or by rotating the rotor assembly relative to the torch, the end ring and Including overlay welding forming a weld metal that constitutes a conduction path with the conductor bar,
The overlay welding process includes:
A first step of starting arc discharge between the electrode of the torch and the end ring and the conductor bar to form a molten pool;
The arc is formed between the electrode of the torch and the molten pool so that arc discharge does not protrude from the molten pool, and the torch is rotated or the rotor assembly is rotated with respect to the torch. And a second step of making the induction rotating electrical machine. In the manufacturing method of the induction rotating electric machine according to claim 1,
In the groove forming step, the deepest portion of the weld groove is on the outer side in the axial direction of the weld open front end portion on the outer peripheral surface side of the end ring, and the radial direction of the weld open front end portion on the end face side of the end ring The method of manufacturing an induction rotating electrical machine, wherein the welding groove is formed so as to be located outside. In the manufacturing method of the induction rotating electric machine according to claim 1 or 2,
In the build-up welding step, the cross-sectional area of the weld metal in a plane including the rotation center axis of the rotor is larger than the cross-sectional area of the conductor bar in a plane orthogonal to the rotation center axis. A method of manufacturing an induction rotating electrical machine, wherein the weld metal is formed. A plurality of conductor bars which are housed in each of a plurality of slots formed in the rotor core and whose both end portions protrude from an axial end surface of the rotor core, and are disposed at both ends of the rotor core; In a method of manufacturing an induction rotating electrical machine including a pair of end rings having fitting portions into which ends of conductor bars protruding from both axial end faces of the iron core are fitted,
An assembly step in which the conductor bar is accommodated in a slot of the rotor core, and an end portion of the conductor bar is fitted into a fitting portion of the end ring to form a rotor assembly;
A groove forming step of forming a welding groove from the end face side of the end ring to the outer peripheral face side of the end ring in the entire circumference of the end ring in a state where the conductor bar and the end ring are fitted. When,
The weld groove is overlaid by arc welding by rotating the torch around the rotor assembly a plurality of times, or by rotating the rotor assembly around the torch a plurality of times. An overlay welding step of forming a weld metal that constitutes a conduction path between the end ring and the conductor bar by the overlay layer of
In the build-up welding process, a gap between the conductor bar and the fitting portion of the end ring is covered with a first build-up layer. In the manufacturing method of the induction rotating electric machine according to claim 4,
In the build-up welding process, the build-up amount for forming the first build-up layer is less than the build-up amount for forming the build-up layers after the second layer. A method of manufacturing an induction rotating electrical machine. In the manufacturing method of the induction rotating electric machine according to claim 4 or 5,
In the groove forming step, the deepest portion of the weld groove is on the outer side in the axial direction of the weld open front end portion on the outer peripheral surface side of the end ring, and the radial direction of the weld open front end portion on the end face side of the end ring The method of manufacturing an induction rotating electrical machine, wherein the welding groove is formed so as to be located outside. In the manufacturing method of the induction rotating electric machine according to any one of claims 4 to 6,
In the build-up welding step, the cross-sectional area of the weld metal in a plane including the rotation center axis of the rotor is larger than the cross-sectional area of the conductor bar in a plane orthogonal to the rotation center axis. A method of manufacturing an induction rotating electrical machine, wherein the weld metal is formed.

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