Stator assembly method and stator assembly apparatus

A stator assembly method in which coils that have slot housed portions and coil ends formed from a conductive wire are mounted to an annular stator core that has a plurality of teeth that extend from a back yoke toward an inner side in a radial direction and slots formed between two of the teeth.

BACKGROUND

The present disclosure relates to a stator assembly method and a stator assembly apparatus, and in particular to a method and an apparatus that mount coils that each have slot housed portions and coil end portions formed from a conductive wire to an annular stator core that has a plurality of teeth that extend radially inward from a back yoke and slots formed between two teeth.

Hitherto, there have been known a stator assembly method and a stator assembly apparatus that mount coils to an annular stator core (see Japanese Patent Application Publication No. 2011-193597, for example). The stator core has a plurality of teeth that extend radially inward from a back yoke, and slots formed between two teeth. The coils are formed from a conductive wire, and each have linear portions to be housed in the slots and coil end portions positioned outside the slots. A plurality of coils are combined with each other to form an annular coil assembly.

The stator assembly apparatus includes a jig disposed on the radially inner side of the stator core. The jig is formed in a generally circular column shape, and has a plurality of holding grooves which are provided in the outer peripheral surface of the jig and to which the linear portions of the coils of the coil assembly are to be inserted. The stator assembly method includes a step of attaching coils sequentially in the circumferential direction to holding grooves of a jig one by one, and a step of disposing the coils, which have been attached to the jig, in a radially inner space of a stator core and pushing out the coils radially from the radially inner side toward the radially outer side to insert linear portions of the coils into slots of the stator core.

SUMMARY

In the stator assembly method and the stator assembly apparatus described in Japanese Patent Application Publication No. 2011-193597, the jig in a generally circular column shape is structured such that the interval of adjacent holding grooves formed in the outer peripheral surface of the jig is smaller at a position closer to the center of the jig. Thus, in the course of assembling the coils of the coil assembly to the jig, the coils are deformed such that the linear portions on both sides, which have been relatively far from each other, are brought closer to each other, and thereafter deformed again when the coils are assembled to the stator core.

Therefore, in the technique in which the coils configured as described above are assembled to the jig in a generally circular column shape and then mounted to the annular stator core, portions of the coil end portions that are preferably not bent are deformed to be work-hardened when the coils are assembled to the jig before being assembled to the stator core. For example, for coils formed in a generally hexagonal shape, the portions of the coil end portions that are preferably not bent include linear oblique portions of the coil end portions. Therefore, portions of the coils to be housed in the slots are defoimed significantly after the coils are assembled to the stator core, and a pressure (surface pressure) with which the coils are pressed against the wall surfaces of teeth in the slots is increased, which increases the insertion load. As a result, there may be a flaw in the coils, degradation in accuracy in shape of the coils after being assembled, and a disadvantage such as an increase in size of equipment, for example.

The present disclosure has been made in view of the foregoing issues, and therefore an exemplary aspect of the disclosure provides a stator assembly method and a stator assembly apparatus capable of suppressing the insertion load of inserting coils into slots when a coil assembly, in which a plurality of coils that each have coil end portions and linear portions are combined with each other, is inserted from the radially inner side toward the radially outer side of an annular stator core to be mounted to the stator core.

An exemplary aspect of the present disclosure provides a stator assembly method in which coils that have slot housed portions and coil ends formed from a conductive wire are mounted to an annular stator core that has a plurality of teeth that extend from a back yoke toward an inner side in a radial direction and slots formed between two of the teeth, including: forming a coil assembly in which a plurality of the coils are disposed in an annular arrangement and in which the slot housed portions of two of the coils located away from each other in a circumferential direction form slot housed bundles to be housed in the same slot of the stator core; moving guide jigs configured to form guide surfaces with respect to tooth holes, of the coil assembly, formed between two of the slot housed bundles disposed adjacent to each other in the circumferential direction and inserting the guide jigs into the tooth holes to dispose the guide jigs with respect to the coil assembly; and pushing out the plurality of the coils which form the coil assembly radially from a radially inner side toward a radially outer side, with the coil assembly disposed in a radially inner space of the stator core and with the guide surfaces of the guide jigs in parallel with wall surfaces of the teeth, to insert the slot housed portions of the coils into the slots of the stator core while the guide jigs are guiding the plurality of the coils.

Another aspect of the present disclosure provides a stator assembly apparatus that mounts coils that have slot housed portions and coil ends formed from a conductive wire to an annular stator core that has a plurality of teeth that extend from a back yoke toward an inner side in a radial direction and slots formed between two of the teeth, including: guide jigs configured to form guide surfaces, the guide jigs being moved with respect to tooth holes of a coil assembly and inserted into the tooth holes to be disposed with respect to the coil assembly, the tooth holes being formed between two of slot housed bundles, which are disposed adjacent to each other in a circumferential direction, the coil assembly in which a plurality of the coils are disposed in an annular arrangement and in which the slot housed portions of two of the coils located away from each other in a circumferential direction form the slot housed bundles to be housed in the same slot of the stator core; and a pusher for pushing out the plurality of the coils which faun the coil assembly radially from a radially inner side toward a radially outer side, with the coil assembly disposed in a radially inner space of the stator core and with the guide surfaces of the guide jigs in parallel with wall surfaces of the teeth, to insert the slot housed portions of the coils into the slots of the stator core while the guide jigs are guiding the plurality of the coils.

According to the present disclosure, it is possible to suppress the insertion load of inserting coils into slots when a coil assembly, in which a plurality of coils that each have coil ends and linear portions are combined with each other, is inserted from the radially inner side toward the radially outer side of an annular stator core to be mounted to the stator core.

DETAILED DESCRIPTION OF EMBODIMENTS

A stator assembly method and a stator assembly apparatus according to a specific embodiment of the present disclosure will be described below with reference to the drawings.

FIG. 1is a perspective view of a stator that has been assembled using a stator assembly method and a stator assembly apparatus according to an embodiment of the present disclosure.FIG. 2illustrates a procedure for forming a coil assembly in an annular cage shape from a plurality of coaxially wound coils in the embodiment.FIG. 3illustrates the positional relationship between two coaxially wound coils of the same phase, slot housed portions of which are to be housed in the same slot, in the embodiment.FIG. 3Ais a view as seen from the axial center side.FIG. 3Bis a view as seen from a side in the axial direction.

A stator assembly apparatus10according to the embodiment is an apparatus that assembles a stator12, which serves as a stationary element for use in a rotary electric machine such as a three-phase AC motor, for example. The stator12is a member disposed on the radially outer side with respect to a rotor, which serves as a rotary element, via a predetermined air gap to generate a magnetic field that rotates the rotor when the stator12is energized. The stator12includes a stator core14and stator coils16.

The stator core14is a member formed in a hollow cylindrical shape. A space (radially inner space)18configured to house the rotor is formed on the radially inner side of the stator core14. The stator core14may be formed by stacking a plurality of magnetic steel sheets coated for insulation in the axial direction. A cylindrical yoke formed from a material compacted from soft magnetic powder and coated for insulation may be attached to an end surface of the stator core14on the radially outer side.

The stator core14has a back yoke20formed in an annular shape, and teeth22that extend from an end surface of the back yoke20on the radially inner side toward the radially inner side (toward the axial center). The back yoke20includes a plurality of (e.g. 48) teeth22provided in the circumferential direction. The teeth22are provided at equal intervals along the circumferential direction. A slot24in which the stator coil16is held is formed between two teeth22that are adjacent to each other in the circumferential direction.

The stator core14is provided with lug portions26configured to attach and fix the stator12to a motor case. The lug portions26are formed in a mound shape to project radially outward from an end surface (outer peripheral surface) of the body (specifically, the back yoke20) of the stator core14on the radially outer side. A plurality of (e.g. three) lug portions26are provided away from each other in the circumferential direction. The lug portions26are provided with through holes28that penetrate in the axial direction. The stator12is fixed to the motor case with bolts that penetrate the through holes28of the lug portions26fastened to nuts via the motor case.

The stator coils16are formed from a conductive wire. The conductive wire is constituted of highly conductive metal such as copper or aluminum, for example. The conductive wire may be formed in a circular shape in cross section, but may be a rectangular conductive wire formed in a rectangular shape (specifically, an oblong shape) in cross section. In the following description, the conductive wire is assumed to be a rectangular conductive wire. The corner portions, in cross section, of the rectangular conductive wire may be rounded. The stator core14includes a plurality of (e.g. 48) stator coils16disposed in the circumferential direction.

The stator coils16are each a coaxially wound coil (cassette coil) shaped by bending a conductive wire wound a plurality of turns (e.g. five turns). In the following description, the stator coils16will be referred to as “coaxially wound coils16”. The coaxially wound coils16are shaped by a winding forming device by winding a single linear conductive wire a predetermined plural number of turns while being formed into an elliptical shape, and thereafter by a shaping device by bending the winding into a generally hexagonal shape or a generally octagonal shape.

The coaxially wound coils16each have slot housed portions30and32and coil end portions34and36(i.e., coil ends). The slot housed portions30and32are portions to be housed in the slots24of the stator core14, and extend generally linearly so as to penetrate the slots24in the axial direction. The slot housed portion30and the slot housed portion32are housed in different slots24located at a predetermined distance away from each other in the circumferential direction of the stator core14. The coil end portions34and36are portions that project axially outward from end portions of the stator core14in the axial direction, and are curved so as to link the two slot housed portions30and32, which are located away from each other in the circumferential direction, to each other.

The coaxially wound coils16are configured such that a plurality of conductive wires are stacked on each other, and configured such that a predetermined clearance is formed between conductive wires that are adjacent to each other in the stacking direction. In the case where the conductive wire is a rectangular conductive wire, the stacking direction of the conductive wires may be the direction of the short sides, in cross section, of the rectangular conductive wire. The coaxially wound coils16are formed in a trapezoidal shape in section such that the separation distance (interval) between the two slot housed portions30and32is varied in accordance with the position in the stacking direction. The coaxially wound coils16are formed in a trapezoidal shape in section so that the slot housed portions30and32of the coaxially wound coils16are appropriately housed in the slots24. The coaxially wound coils16are assembled to the stator core14such that the stacking direction of the conductive wires coincides with radial directions that are orthogonal to the axial direction of the stator core14.

The coil end portions34and36of the coaxially wound coils16are formed into a plurality of different non-linear shapes. Specifically, the coil end portions34and36are formed into three types of non-linear shapes, and crank-shaped into a crank shape in which the conductive wire is bent in a staircase shape in the radial direction of the stator core14, arc-shaped into an arc shape in which the conductive wire is curved in accordance with the arc of the annular stator core14, and edgewise-shaped into a bent shape in which the conductive wire is bent in the direction of the long sides, in cross section, of the rectangular conductive wire. Crank-shaping is a bending process performed for a lane change between conductive wires in the stacking direction of the rectangular conductive wires. Arc-shaping is a bending process performed in order that the coaxially wound coils16are efficiently housed in the slots24. Edgewise-shaping is a bending process performed in order that the plurality of coaxially wound coils16are efficiently disposed.

A plurality of coaxially wound coils16are disposed in the circumferential direction to constitute the coil assembly40in an annular cage shape. The coil assembly40is formed in an annular cage shape with the plurality of coaxially wound coils16arranged side by side in the circumferential direction and disposed in an annular arrangement. The coaxially wound coils16are configured such that the interval of the slot housed portions30and32on both sides is relatively small before the coaxially wound coils16are combined with each other to form the coil assembly40. After the plurality of coaxially wound coils16are disposed in an annular arrangement and combined with each other to form the coil assembly40, the coil assembly40has an outside diameter that allows the coil assembly40to be housed in the radially inner space18of the stator core14.

The coil assembly40is formed such that the contents of the following (A) to (C) are achieved. (A) The plurality of coaxially wound coils16are disposed so as to be housed in the slots24as displaced one by one in the circumferential direction. (B) Two coaxially wound coils16disposed adjacent to each other in the circumferential direction are assembled such that the rectangular conductive wires in each level alternately overlap each other in the stacking direction (i.e. the radial direction). (C) Two coaxially wound coils16of the same phase disposed a predetermined distance away from each other in the circumferential direction are assembled such that the rectangular conductive wire in each level of the slot housed portion30of one of the coaxially wound coils16and the rectangular conductive wire in each level of the slot housed portion32of the other are housed side by side alternately in the stacking direction (i.e. the radial direction) in the same slot24of the stator core14.

When the assembly described in (B) is performed, tooth holes42, into which the teeth22of the stator core14are to be inserted to be disposed, are formed between the slot housed portions30and32of two coaxially wound coils16, of the coil assembly40, disposed adjacent to each other in the circumferential direction. In the following description, a bundle of the slot housed portions30and32of two coaxially wound coils16, of the coil assembly40, to be housed in the same slot24will be referred to as a “slot housed bundle46”. That is, the tooth holes42are each formed between two slot housed bundles46, of the coil assembly40, disposed adjacent to each other in the circumferential direction.

In the case where the stator12is applied to a three-phase AC motor, for example, the coaxially wound coils16constitute any of a U-phase coil, a V-phase coil, and a W-phase coil. For example, the coil assembly40is configured such that two coils of the same phase, namely U-phase coils, V-phase coils, and W-phase coils, which are the coaxially wound coils16, are disposed side by side in the circumferential direction so that six coaxially wound coils16arranged in the circumferential direction form one pole.

The stator12includes insulating members44configured to secure electrical insulation between the stator core14and the coaxially wound coils16. The insulating members44each have a shape that matches the slot24of the stator core14, and are each formed in a C-shape in section to be mounted to the slot24. The insulating members44are each formed in a thin film shape from paper, a resin (such as a thermosetting resin or a thermoplastic resin, for example), or the like. After the coil assembly40is formed from a predetermined plural number of coaxially wound coils16, the insulating members44are mounted to the coil assembly40by fitting the insulating members44onto the slot housed portions30and32of the coaxially wound coils16(i.e. the slot housed bundles46of the coil assembly40) from the radially outer side toward the radially inner side of the slot housed portions30and32.

Next, a procedure for assembling the stator12using the stator assembly apparatus10according to the embodiment will be described with reference toFIGS. 4 to 10.

FIG. 4is a perspective view of a guide jig of the stator assembly apparatus10according to the embodiment.FIG. 5illustrates steps of assembling the stator12in the stator assembly apparatus10according to the embodiment. InFIG. 5, from the viewpoint of the convenience of description and the ease of understanding, the stator assembly apparatus10and the stator12are illustrated as cut into a half along a direction that is parallel to the axis.

In the embodiment, the stator assembly apparatus10includes guide jigs50that are necessary to assemble the stator12(specifically, to insert the coaxially wound coils16into the slots24of the stator core14). The guide jigs50are attached to each of the tooth holes42of the coil assembly40. A plurality of guide jigs50are provided to one coil assembly40. The guide jigs50are attached to the coil assembly40after the coil assembly40in an annular cage shape is formed and after the insulating members44are mounted to the slot housed portions30and32of the coaxially wound coils16of the coil assembly40.

The coil assembly40is configured such that the separation distance between the two slot housed portions30and32of each coaxially wound coil16(i.e. the interval of two slot housed bundles46that are adjacent to each other in the circumferential direction) is small before the slot housed portions30and32of each coaxially wound coil16are inserted into the slots24of the stator core14compared to that after such insertion. That is, the coil assembly40is configured such that the axial length (the distance from the distal end of the coil end portion34in the axial direction to the distal end of the coil end portion36in the axial direction) is large and the outside diameter is small (specifically, the outside diameter is slightly smaller than the inside diameter of the teeth22of the stator core14) before the insertion described above compared to those after the insertion.

In the following description, for convenience, the coil assembly40before the slot housed portions30and32are inserted into the slots24of the stator core14will be referred to as an “initial coil assembly40”, and the coil assembly40after the slot housed portions30and32are inserted into the slots24of the stator core14will be referred to as a “final coil assembly40”.

As illustrated inFIG. 4, the guide jigs50each have a first guide jig52, the entirety of which is to be inserted into the tooth hole42of the initial coil assembly40. The first guide jig52is a jig formed in the shape of a plate that extends in both the radial direction and the axial direction of the stator12and the stator core14so as to be fitted in the tooth hole42of the initial coil assembly40. The first guide jig52is formed in a tapered shape in which the thickness (width) in the circumferential direction becomes smaller from the radially outer side toward the radially inner side.

The first guide jigs52are provided adjacently on the radially inner side of the teeth22to oppose the teeth22when the slot housed portions30and32of the coaxially wound coils16of the coil assembly40are inserted into the slots24. The first guide jigs52each have a planar guide surface. The guide surfaces of the first guide jigs52are parallel to the wall surfaces of the teeth22(i.e. side surfaces that face the slots24in the circumferential direction) when the coaxially wound coils16are inserted into the slots24. The first guide jigs52are formed such that the width (i.e. the thickness in the circumferential direction) at the position of the radially outer end is generally the same as or slightly larger than the width at the distal end (the position of the radially inner end) of the teeth22of the stator core14. The first guide jigs52have a function of guiding the coaxially wound coils16of the coil assembly40in the circumferential direction when the coaxially wound coils16are inserted into the slots24.

The guide jigs50each also have second and third guide jigs54and56that are partially inserted into the tooth holes42of the initial coil assembly40. The second guide jig54is disposed adjacently on one side, in the axial direction, with respect to the first guide jig52. The third guide jig56is disposed adjacently on the other side, in the axial direction, with respect to the first guide jig52. The second and third guide jigs54and56are each formed in the shape of a wedge that extends in the radial direction and that has a pointed end on the radially inner side.

The second and third guide jigs54and56are each formed in a tapered shape in which the thickness in the circumferential direction becomes smaller from the radially outer side toward the radially inner side. The second guide jigs54are provided adjacently on the outer side, in the axial direction, of the teeth22to oppose the teeth22when the coaxially wound coils16of the coil assembly40are inserted into the slots24. The third guide jigs56are provided adjacently on the outer side, in the axial direction, of the teeth22to oppose the teeth22when the coaxially wound coils16of the coil assembly40are inserted into the slots24.

The second and third guide jigs54and56extend in the radial direction on the outer side, in the axial direction, of the stator core14so as to overlap the teeth22as seen in the axial direction. The second and third guide jigs54and56are formed such that the width (i.e. the thickness in the circumferential direction) of the second and third guide jigs54and56at each position in the radial direction on the radially inner side is generally the same as the width of the first guide jigs52at the same position in the radial direction, and formed such that the width of the second and third guide jigs54and56at each position in the radial direction is equal to or more than the width of the teeth22at the same position in the radial direction.

The second and third guide jigs54and56have a function of guiding the coaxially wound coils16of the coil assembly40in the circumferential direction when the slot housed portions30and32of the coaxially wound coils16are inserted into the slots24, and have a function of preventing the insulating members44from slipping off in the axial direction from the teeth22.

The second and third guide jigs54and56are each provided with cut portions60and62. The cut portions60and62are portions that are provided on the radially inner side and that communicate with holes formed between two first guide jigs52that are adjacent to each other in the circumferential direction and the slots24of the stator core14when the coaxially wound coils16are inserted into the slots24. When two second guide jigs54disposed adjacent to each other in the circumferential direction are arranged in the circumferential direction, the cut portion60of one of the guide jigs54and the cut portion62of the other guide jig54form a hole that guides the coaxially wound coils16when the coaxially wound coils16are inserted into the slots. When two third guide jigs56disposed adjacent to each other in the circumferential direction are arranged in the circumferential direction, the cut portion60of one of the guide jigs56and the cut portion62of the other guide jig56form a hole that guides the coaxially wound coils16when the coaxially wound coils16are inserted into the slots.

In the stator assembly apparatus10according to the embodiment, the initial coil assembly40in which the plurality of coaxially wound coils16are disposed in an annular arrangement is formed, the insulating members44are mounted to the slot housed portions30and32of the coaxially wound coils16of the initial coil assembly40, and thereafter the guide jigs50are inserted into the tooth holes42of the initial coil assembly40to be attached. Specifically, first, as illustrated inFIG. 5A, the initial coil assembly40in which the plurality of coaxially wound coils16are disposed in an annular arrangement and to which the insulating members44are mounted, the plurality of guide jigs50, and the stator core14are prepared. Then, as illustrated inFIG. 5B, the first guide jigs52and the third guide jigs56are moved from the radially outer side toward the radially inner side of the coil assembly40to be inserted into the tooth holes42of the initial coil assembly40so that the guide jigs52and56are disposed with respect to the coil assembly40.

As described above, the initial coil assembly40is configured such that the outside diameter of the initial coil assembly40is slightly smaller than the inside diameter of the teeth22of the stator core14. Thus, the stator core14can be assembled to the initial coil assembly40, in which the first guide jigs52and the third guide jigs56have been inserted into the tooth hole42, from the side, in the axial direction, on which the second guide jigs54have not been attached yet.

Thus, after the first and third guide jigs52and56are attached to the initial coil assembly40, as illustrated inFIG. 5C, the stator core14, in which the teeth22project toward the radially inner side, is assembled to the initial coil assembly40from the side, in the axial direction, on which the second guide jigs54have not been attached yet. When such assembly is performed, the initial coil assembly40is disposed in the radially inner space18of the stator core14. Lastly, as illustrated inFIG. 5D, the second guide jigs54are moved from the radially outer side toward the radially inner side of the coil assembly40to be inserted into the tooth holes42of the initial coil assembly40so that the second guide jigs54are disposed with respect to the coil assembly40.

After insertion and disposition of the initial coil assembly40, to which the first and third guide jigs52and56have been attached, and the stator core14, or after insertion of the second guide jigs54into the tooth holes42after such insertion and disposition, the initial coil assembly40and the stator core14are positioned with respect to each other in the circumferential direction. This positioning is performed such that the first guide jigs52are provided adjacently on the radially inner side of the teeth22to oppose the teeth22, and such that the slot housed portions30and32of the coaxially wound coils16are provided adjacently on the radially inner side of the slots24to oppose the slots24.

FIG. 6is a perspective view of a pushing device of the stator assembly apparatus10according to the embodiment.FIG. 6Aillustrates a state before insertion of the coaxially wound coils16into the slots24of the stator core14.FIG. 6Billustrates a state during insertion of the coaxially wound coils16into the slots24of the stator core14.FIG. 7is a view of the pushing device of the stator assembly apparatus10according to the embodiment, illustrating a state before insertion of the coaxially wound coils16into the slots24.FIG. 8is a view of the pushing device of the stator assembly apparatus10according to the embodiment, illustrating a state during insertion of the coaxially wound coils16into the slots24.FIGS. 7A and 8Aare each a side view of the pushing device.FIGS. 7B and 8Bare each a sectional view of the pushing device illustrated inFIGS. 7A and 8Btaken along the line III-III.FIGS. 7C and 8Care each a side view of the pushing device illustrated inFIGS. 7B and 8Bin the state of being cut along the line IV-IV.

The stator assembly apparatus10also includes a pushing device70that generates a pressing force that is necessary to assemble the stator12(specifically, to insert the coaxially wound coils16into the slots24of the stator core14). The pushing device70has a holding stand72and a roller74.

The holding stand72holds the stator12which includes the coil assembly40, in which the insulating members44are mounted to the slot housed portions30and32of the coaxially wound coils16and in which the guide jigs50are attached to the tooth holes42, and the stator core14. The holding stand72holds the stator12so as to be rotatable about an axis. The holding stand72holds the stator12such that the axis of the stator12is directed in the horizontal direction as illustrated inFIG. 6, for example.

The roller74is a member that pushes out the plurality of coaxially wound coils16(specifically, the coil end portions34and36), which constitute the coil assembly40of the stator12which is held by the holding stand72, radially from the radially inner side toward the radially outer side. The roller74is disposed on the radially inner side of the coil assembly40, and disposed on the axially outer side of the stator core14. The roller74is a member formed in a circular column shape, and is disposed such that the axis of the roller74extends in the same direction as the axis of the stator12.

The roller74includes a roller74athat contacts the coil end portions34of the coaxially wound coils16of the coil assembly40, and a roller74bthat contacts the coil end portions36of the coaxially wound coils16of the coil assembly40. The roller74aand the roller74bare coupled to each other by a shaft76that penetrates the radially inner side of the coil assembly40in the axial direction.

The holding stand72and the roller74are relatively movable in the radial direction. For example, the roller74is movable with respect to the holding stand72in the radial direction of the stator12which is held by the holding stand72. In the case where the holding stand72holds the stator12such that the axis of the stator12is directed in the horizontal direction, the holding stand72(i.e. the stator12) and the roller74are relatively movable in the up-down direction. The relative movement of the holding stand72and the roller74described above is performed in such a range that the slot housed portions30and32of the coaxially wound coils16of the coil assembly40are appropriately housed in the slots24, and that the shaft76does not contact the distal ends of the teeth22of the stator core14.

The roller74aand the roller74bmay not be coupled to each other by the shaft76, and may be supported in a so-called cantilever manner to contact the coil end portions34and36, respectively. The roller74aand the roller74bmay be coupled to each other by the shaft76, and only one of the two rollers74aand74bmay be supported.

FIG. 9illustrates the positional relationship between the guide jig50and the coaxially wound coil16during stator assembly by the stator assembly apparatus10according to the embodiment.FIG. 9Aillustrates a state before insertion of the slot housed portions30and32into the slots24.FIG. 9Billustrates a state after insertion of the slot housed portions30and32into the slots24.FIG. 10illustrates the effect of stator assembly by the stator assembly apparatus10according to the embodiment.

In the stator assembly apparatus10according to the embodiment, as described above, the guide jigs50are attached to the tooth holes42of the initial coil assembly40, the initial coil assembly40is inserted into the radially inner space18of the stator core14to be disposed, and thereafter the stator12, in which the initial coil assembly40with the guide jigs50is disposed in the radially inner space18of the stator core14, is rotatably set to the holding stand72(the state illustrated inFIGS. 6A and 7). In the following description, the stator12with the guide jigs50will be referred to as a “jigged stator12” as appropriate. In the jigged stator12, bolts or the like (not illustrated) are used for fixation such that the positional relationship between the guide jigs50and the positional relationship between the stator core14and the guide jigs50are not varied.

The roller74is gradually relatively moved with respect to the holding stand72from the side of the axial center of the stator12toward the radially outer side while rotating the jigged stator12which is held by the holding stand72. When such rotation of the stator12and relative movement of the roller74are performed, the roller74aconsecutively presses the coil end portions34of the coaxially wound coils16, which constitute the coil assembly40of the stator12, radially outward while consecutively contacting the coil end portions34, and the roller74bconsecutively presses the coil end portions36of the coaxially wound coils16radially outward while consecutively contacting the coil end portions36.

When the coil end portions34and36of the coaxially wound coils16are pressed toward the radially outer side by the roller74, the slot housed portions30and32, which are linked to the coil end portions34and36, are pulled from the radially inner side toward the radially outer side in accordance with the pressing of the coil end portions34and36. As described above, the initial coil assembly40and the stator core14are positioned with respect to each other in the circumferential direction such that the first guide jigs52are provided adjacently on the radially inner side of the teeth22to oppose the teeth22, and such that the slot housed portions30and32of the coaxially wound coils16are provided adjacently on the radially inner side of the slots24to oppose the slots24. In this event, the guide surfaces of the first guide jigs52are parallel to the wall surfaces of the slots24. The second and third guide jigs54and56are provided with the cut portions60and62which guide the coaxially wound coils16when the coaxially wound coils16are inserted into the slots.

Therefore, the slot housed portions30and32are pulled toward the radially outer side in accordance with the pressing of the coil end portions34and36as described above to be inserted into the slots24while being guided by the first, second, and third guide jigs52,54, and56. In the course of the insertion, the coaxially wound coils16are deformed such that the distance (interval), in the circumferential direction, between the slot housed portions30and the slot housed portions32is gradually increased while the distance, in the axial direction, between the distal end of the coil end portions34in the axial direction and the distal end of the coil end portions36in the axial direction is gradually reduced (seeFIG. 9).

When the slot housed portions30and32of all the coaxially wound coils16that constitute the coil assembly40in an annular cage shape are pressed toward the radially outer side, all the coaxially wound coils16that are present in the circumferential direction are pushed out radially from the radially inner side toward the radially outer side, and thus the slot housed portions30and32are inserted into the slots24while the coaxially wound coils16are guided by the guide jigs50. The slot housed portions30and32are inserted as the slot housed bundle46which include the slot housed portions30and32of two coaxially wound coils16to be housed in the same slot24. After the slot housed portions30and32of all the coaxially wound coils16are inserted into the slots24, relative movement of the roller74toward the radially outer side and rotation of the stator12are stopped.

With such a stator assembly technique, two coaxially wound coils16, which are disposed away from each other in the circumferential direction at different positions in the circumferential direction, are assembled such that the rectangular conductive wires of the slot housed portion30of one of the coaxially wound coils16and the rectangular conductive wires of the slot housed portion32of the other coaxially wound coil16are arranged alternately in the radial direction in the same slot24. In addition, after the coil assembly40in which a predetermined plural number of coaxially wound coils16are disposed in an annular arrangement is formed, the slot housed portions30and32of the plurality of coaxially wound coils16which constitute the coil assembly40can be inserted into the slots24of the annular stator core14.

That is, after the initial coil assembly structured as described above is formed, the coil assembly40can be assembled to the annular stator core14by attaching the guide jigs50to the tooth holes42which are formed between the slot housed portions30and32(i.e. two slot housed bundles46) of two coaxially wound coils16, of the initial coil assembly40, disposed adjacent to each other in the circumferential direction, and pushing out the coaxially wound coils16toward the radially outer side while inserting the slot housed portions30and32of the coaxially wound coils16into the slots24by pressing the coil end portions34and36of the coaxially wound coils16, which constitute the initial coil assembly40with the guide jigs50, toward the radially outer side using the roller74of the pushing device70, with the initial coil assembly40with the guide jigs50disposed in the radially inner space18of the stator core14and with the guide surfaces of the guide jigs50(specifically, the first guide jigs52) in parallel with the wall surfaces of the teeth22.

In the stator assembly technique performed by the stator assembly apparatus10according to the embodiment, when the coil assembly40, in which the guide jigs50are attached to the tooth holes42, is assembled to the annular stator core14by pushing out the coaxially wound coils16toward the radially outer side, the slot housed portions30and32of the coaxially wound coils16are supported by the guide jigs50. Specifically, the slot housed portions30and32are guided as interposed between two first guide jigs52provided adjacently on both sides in the circumferential direction, guided by the cut portions60and62of two second guide jigs54that are adjacent to each other in the circumferential direction, and guided by the cut portions60and62of two third guide jigs56that are adjacent to each other in the circumferential direction.

Therefore, with the embodiment, as illustrated inFIG. 10, in guiding the slot housed portions30and32of the coaxially wound coils16of the coil assembly40during insertion of the slot housed portions30and32into the slots24, it is possible to suppress bulging of the slot housed portions30and32in the circumferential direction, and to suppress buckling of the slot housed portions30and32.

In a configuration (a configuration according to a contrastive example) in which a plurality of coaxially wound coils16are disposed in a guide jig, in the outer peripheral surface of which a plurality of holding grooves are formed, unlike the configuration according to the embodiment, in the course of assembling the coils16to the guide jig, the coils16are deformed such that the slot housed portions30and32on both sides, which have been relatively far from each other, are brought closer to each other, and thereafter deformed again when the coils16are assembled to the stator core14. Therefore, with the configuration according to the contrastive example, portions (e.g. linear oblique side portions of the coil end portions34and36) of the coil end portions34and36that are preferably not bent are deformed to be work-hardened when the coils16are assembled to the jig before being assembled to the stator core14. In this case, the slot housed portions30and32to be housed in the slots24are deformed significantly after the coils16are assembled to the stator core14, and a pressure (surface pressure) with which the coils16are pressed against the wall surfaces of teeth22in the slots24is increased, which increases the insertion load.

In the configuration according to the embodiment, in contrast, deformation of the slot housed portions30and32of the coils16closer to each other is not necessary, or the amount of such deformation is significantly small, in the course of assembling the coils16and the guide jigs50to each other before the coaxially wound coils16of the coil assembly40are assembled to the stator core14. Therefore, the oblique side portions etc. of the coil end portions34and36are not deformed to be work-hardened during assembly of the coils16and the guide jigs50, and deformation of the slot housed portions30and32is not increased.

Thus, with the embodiment, a pressure (surface pressure), with which the coils16are pressed against the wall surfaces of the teeth22in the slots24, is not increased during assembly of the coils16to the stator core14, which suppresses the insertion load during insertion of the coils16into the slots24. Therefore, it is possible to prevent a flaw in the coils16and degradation in accuracy in shape of the coils16after being assembled to the stator core14, and to avoid a disadvantage such as an increase in size of manufacturing equipment.

In the stator assembly apparatus10according to the embodiment, the second and third guide jigs54and56are formed such that the width (i.e. the thickness in the circumferential direction) of the second and third guide jigs54and56at each position in the radial direction is equal to or more than the width of the teeth22of the stator core14at the same position in the radial direction. Therefore, with the embodiment, rubbing of the rectangular conductive wires of the slot housed portions30and32of the coaxially wound coils16of the coil assembly40against surfaces (in particular, sharp corner portions formed on end surfaces) of the teeth22can be avoided when the slot housed portions30and32are guided by the second and third guide jigs54and56when the slot housed portions30and32are inserted into the slots24. Thus, it is possible to prevent a flaw in the coaxially wound coils16and a flaw in the surfaces of the teeth22, and to prevent the insulating members44from being easily broken.

In the stator assembly technique performed by the stator assembly apparatus10according to the embodiment, when the coil assembly40, in which the guide jigs50are attached to the tooth holes42, is assembled to the annular stator core14by pushing out the coaxially wound coils16toward the radially outer side, the assembly can be performed while deforming the coaxially wound coils16using only pressing by the roller74of the pushing device70toward the radially outer side.

Therefore, in the embodiment, unlike a structure in which a pressing jig that presses the coaxially wound coils16toward a side in the axial direction is provided, when the coil assembly40is assembled to the stator core14, the coaxially wound coils16are not pressed toward a side in the axial direction by a pressing jig located on a side in the axial direction, and the contact surface between such a pressing jig located on a side in the axial direction and the coaxially wound coils16does not become minute. Thus, a flaw in the coaxially wound coils16can be prevented.

In the stator assembly technique performed by the stator assembly apparatus10according to the embodiment, when the coil assembly40, in which the guide jigs50are attached to the tooth holes42, is assembled to the annular stator core14by pushing out the coaxially wound coils16toward the radially outer side, the assembly is performed with the stator core14held by the holding stand72without moving the stator core14. Thus, it is not necessary to provide a device that moves the stator core14, which makes it possible to simplify the stator assembly apparatus10.

In the stator assembly technique performed by the stator assembly apparatus10according to the embodiment, the initial coil assembly40in which the plurality of coaxially wound coils16are disposed in an annular arrangement is formed, and thereafter the insulating members44in a C-shape in section are inserted into the slot housed portions30and32of the coaxially wound coils16of the initial coil assembly40from the radially outer side toward the radially inner side. As described above, the tooth holes42, into which the teeth22of the stator core14are to be inserted to be disposed, are formed between the slot housed portions30and32of two coaxially wound coils16, of the coil assembly40, disposed adjacent to each other in the circumferential direction. Thus, spaces in which the teeth22or the like are not present are formed in the circumferential direction of the slot housed portions30and32of the coaxially wound coils16before the coil assembly40is assembled to the stator core14. Therefore, the insulating members44can be easily inserted into the slot housed portions30and32of the coaxially wound coils16. Insertion of the insulating members44can be performed at the same time as insertion of the coils unlike the related art, in which insertion of the insulating members and insertion of the coils are performed in separate processes. Therefore, it is possible to shorten the working time, and to improve the productivity.

After the insulating members44are mounted to the slot housed portions30and32of the coaxially wound coils16from the radially outer side as described above, the coaxially wound coils16of the coil assembly40are pushed out toward the radially outer side to be assembled to the annular stator core14. In this event, the slot housed portions30and32of the coaxially wound coils16are moved from the radially inner side toward the radially outer side together with the insulating members44to be inserted into the slots24of the stator core14. Therefore, the insulating members44in a thin film shape, which are disposed between the coaxially wound coils16and the stator core14, can be disposed appropriately in the slots24when the coil assembly40is assembled to the annular stator core14by pushing out the coaxially wound coils16toward the radially outer side, which suppresses formation of wrinkles in the insulating members44or a break of the insulating members44.

In the embodiment described above, the pushing device70corresponds to the “pusher,” the first guide jigs52correspond to the “guide jigs,” and the second and third guide jigs54and56correspond to the “widened guide portions.”

In the embodiment described above, the guide jigs50are attached to the initial coil assembly40by inserting the guide jigs50from the radially outer side toward the radially inner side of the coil assembly40. With such a configuration, the guide jigs50can be easily attached to the initial coil assembly40. However, the present disclosure is not limited thereto. The guide jigs50may be attached to the initial coil assembly40by inserting the guide jigs50from the radially inner side toward the radially outer side of the coil assembly40if there is a sufficient space on the radially inner side of the initial coil assembly40.

In the embodiment described above, the rollers74aand74bwhich push out the coaxially wound coils16which constitute the coil assembly40radially from the radially inner side toward the radially outer side are formed in a circular column shape. However, the present disclosure is not limited thereto. The rollers74aand74bmay be formed in a tapered shape in which corner portions on the radially outer side contacted by the coaxially wound coils16are cut. With such a modification, the coil end portions34and36of the coaxially wound coils16can be shaped so as to be inclined radially outward with respect to the slot housed portions30and32, which can shorten the axial length of the stator12.

In the embodiment described above, the rollers74aand74bwhich push out the coaxially wound coils16which constitute the coil assembly40radially from the radially inner side toward the radially outer side are coupled to each other by the shaft76which penetrates the radially inner side of the coil assembly40in the axial direction. However, the present disclosure is not limited thereto. The roller74aand the roller74bmay be supported separately and independently without using the shaft76. Also with such a modification, the coil end portions34and36of the coaxially wound coils16can be shaped so as to be inclined radially outward with respect to the slot housed portions30and32, which can shorten the axial length of the stator12.

In the embodiment described above, the coaxially wound coils16are pushed out radially while changing the position, in the circumferential direction, of the coil assembly40contacted by the roller74by relatively moving the roller74from the side of the axial center of the stator12toward the radially outer side while rotating the jigged stator12which is held by the holding stand72. However, the present disclosure is not limited thereto. For example, all the coaxially wound coils16over the entire circumference may be pushed out radially at the same time using bar-like or plate-like jigs that are moved from the side of the axial center of the stator12toward the radially outer side.

In the embodiment described above, the insulating members44are disposed with respect to the coil assembly40in which the plurality of coaxially wound coils16are disposed in an annular arrangement, and thereafter inserted into the slots24of the stator core14together with the coaxially wound coils16. However, the present disclosure is not limited thereto. The insulating members44may be disposed in the slots24of the stator core14, and thereafter the coaxially wound coils16of the coil assembly40may be inserted into the slots24.

In the embodiment described above, the guide jigs50are assembled to the coil assembly40after the coil assembly40in an annular cage shape is completed. However, the present disclosure is not limited thereto. The guide jigs50may be assembled when a certain number (e.g. half the number) of the coaxially wound coils16of the coil assembly40are assembled. After that, semi-assemblies each with half the number of the coaxially wound coils16may be assembled to each other to finally assemble the guide jigs50.

In the embodiment described above, The guide jigs50each have a tapered shape, and the guide jigs50are inserted from the radially outer side toward the radially inner side of the coil assembly40. However, the present disclosure is not limited thereto. For example, plate-like guide jigs may be slid from the radially inner side toward the radially outer side of the coil assembly40to be assembled to the coil assembly40.

In the embodiment described above, the coil assembly40, which is constituted of the plurality of coaxially wound coils16, is formed in a cylindrical shape so as to have the same diameter on the side of the coil end portions34and on the side of the coil end portions36. However, the present disclosure is not limited thereto. The coil assembly40may be formed in a conical shape (i.e. a tapered shape in section) so as to have different diameters between the side of the coil end portions34and the side of the coil end portions36.

In relation to the embodiment described above, the following configurations are further disclosed.

[1] A stator assembly method in which coils (16) that have slot housed portions (30,32) and coil end portions (34,36) formed from a conductive wire are mounted to an annular stator core (14) that has a plurality of teeth (22) that extend from a back yoke (20) toward an inner side in a radial direction and slots (24) formed between two of the teeth (22), including: a coil assembly forming step of forming a coil assembly (40) in which a plurality of the coils (16) are disposed in an annular arrangement and in which the slot housed portions (30,32) of two of the coils (16) located away from each other in a circumferential direction form slot housed bundles (46) to be housed in the same slot (24) of the stator core (14); a jig disposing step of moving guide jigs (50) configured to form guide surfaces with respect to tooth holes (42), of the coil assembly (40), formed between two of the slot housed bundles (46) disposed adjacent to each other in the circumferential direction and inserting the guide jigs (50) into the tooth holes (42) to dispose the guide jigs (50) with respect to the coil assembly (40); and a coil inserting step of pushing out the plurality of coils (16) which constitute the coil assembly (40) radially from a radially inner side toward a radially outer side, with the coil assembly (40) disposed in a radially inner space of the stator core (14) and with the guide surfaces of the guide jigs (50) in parallel with wall surfaces of the teeth (22), to insert the slot housed portions (30,32) of the coils (16) into the slots (24) of the stator core (14) while the guide jigs (50) are guiding the plurality of coils (16).

According to the configuration described in [1], a coil assembly (40), in which a plurality of the coils (16) are disposed in an annular arrangement and in which the slot housed portions (30,32) of two of the coils (16) located away from each other in a circumferential direction form slot housed bundles to be housed in the same slot (24), is formed. The guide jigs (50) are moved with respect to the tooth holes (40) of the coil assembly (40), and inserted into the tooth holes (42) to dispose the guide jigs (50) with respect to the coil assembly (40). With the coil assembly (40) disposed in a radially inner space of the stator core (14) and with the guide surfaces of the guide jigs (50) in parallel with wall surfaces of the teeth (22), the slot housed portions (30,32) of the coils (16) are inserted into the slots (24) of the stator core (14) while the guide jigs (50) are guiding the coils (16) of the coil assembly (40).

With such a technique, in constituting the coil assembly (40) from the plurality of coils (16), it is not necessary to assemble the coils (16) to the jigs, and deformation of the coils (16) that brings the slot housed portions (30,32) on both sides closer to each other is not necessary, or the amount of such deformation is small. Thus, it is possible to suppress the insertion load of inserting the coils (16) into the slots (24) in mounting the coil assembly (40) to the stator core (14).

[2] The stator assembly method described in [1], in which: a width of the guide jigs (50) gradually becomes smaller from one side toward the other side; and the jig disposing step includes disposing the guide jigs (50) with respect to the coil assembly (40) such that the one side of the guide jigs (50) faces the radially outer side of the coil assembly (40) and the other side of the guide jigs (50) faces the radially inner side of the coil assembly (40).

[3] The stator assembly method described in [1] or [2], in which the jig disposing step includes disposing the guide jigs (50) with respect to the coil assembly (40) by inserting the guide jigs (50) into the tooth holes (42) from the radially outer side toward the radially inner side of the coil assembly (40).

According to the configuration described in [3], the guide jigs (50) can be easily disposed with respect to the coil assembly (40).

[4] The stator assembly method described in any one of [1] to [3], in which the guide jigs (50) are plate-like members that extend in both the radial direction and an axial direction of the stator core (14).

[5] The stator assembly method described in any one of [1] to [4], in which: the guide jigs (50) include widened guide portions (54,56) provided on an outer side, in the axial direction, of the stator core (14) to extend in the radial direction so as to overlap the teeth (22) as seen in the axial direction; and a width of the widened guide portions (54,56) at each position in the radial direction is equal to or more than a width of the teeth (22) at the same position in the radial direction.

According to the configuration described in [5], rubbing of the conductive wires of the coils (16) of the coil assembly40against surfaces of the teeth22can be avoided when the coils (16) are guided by the widened guide portions (54,56) when the coils (16) are inserted into the slots (24).

[6] The stator assembly method described in any one of [1] to [5], in which the conductive wire is a rectangular conductive wire.

[7] The stator assembly method described in any one of [1] to [6], in which the coils (16) are coaxially wound coils.

[8] The stator assembly method described in any one of [1] to [7], in which two of the coils (16) of the coil assembly (40), the slot housed portions (30,32) of which are to be housed in the same slot (24), are assembled such that the conductive wires of the slot housed portions (30,32) are arranged alternately in the radial direction.

[9] The stator assembly method according to any one of [1] to [8], further including: an insulating member mounting step of mounting insulating members (44) to the plurality of slot housed bundles of the coil assembly (40), which has been formed in the coil assembly forming step, in which the coil inserting step includes inserting the slot housed portions (30,32) of the coils (16) into the slots (24) of the stator core (14) by inserting the slot housed bundles of the coil assembly (40), to which the insulating members (44) have been mounted in the insulating member mounting step, into the slots (24) of the stator core (14).

According to the configuration described in [9], the insulating members (44), which are configured to secure electrical insulation between the coils (16) and the stator core (14), can be easily mounted to the coils (16) of the coil assembly (40).

[10] A stator assembly apparatus (10) that mounts coils (16) that have slot housed portions (30,32) and coil end portions (34,36) formed from a conductive wire to an annular stator core (14) that has a plurality of teeth (22) that extend from a back yoke (20) toward an inner side in a radial direction and slots (24) formed between two of the teeth (22), including: guide jigs (50) configured to form guide surfaces, the guide jigs (50) being moved with respect to tooth holes (42) of a coil assembly (40) and inserted into the tooth holes (42) to be disposed with respect to the coil assembly (40), the tooth holes (42) being formed between two of slot housed bundles, which are disposed adjacent to each other in a circumferential direction, the coil assembly (40) in which a plurality of the coils (16) are disposed in an annular arrangement and in which the slot housed portions (30,32) of two of the coils (16) located away from each other in the circumferential direction form the slot housed bundles to be housed in the same slot (24) of the stator core (14); and a pusher (70) for pushing out the plurality of coils (16) which constitute the coil assembly (40) radially from a radially inner side toward a radially outer side, with the coil assembly (40) disposed in a radially inner space of the stator core (14) and with the guide surfaces of the guide jigs (50) in parallel with wall surfaces of the teeth (22), to insert the slot housed portions (30,32) of the coils (16) into the slots (24) of the stator core (14) while the guide jigs (50) are guiding the plurality of coils (16).

According to the configuration described in [10], a coil assembly (40), in which a plurality of the coils (16) are disposed in an annular arrangement and in which the slot housed portions (30,32) of two of the coils (16) located away from each other in a circumferential direction form slot housed bundles to be housed in the same slot (24), is formed, and thereafter the guide jigs (50) are moved with respect to the tooth holes (42) of the coil assembly (40), and inserted into the tooth holes (42) to dispose the guide jigs (50) with respect to the coil assembly (40). With the coil assembly (40) disposed in a radially inner space of the stator core (14) and with the guide surfaces of the guide jigs (50) in parallel with wall surfaces of the teeth (22), the pusher (70) inserts the slot housed portions (30,32) of the coils (16) into the slots (24) of the stator core (14) while the guide jigs are guiding the coils (16) of the coil assembly (40).

With such an apparatus, in constituting the coil assembly (40) from the plurality of coils (16), it is not necessary to assemble the coils (16) to the jigs, and deformation of the coils (16) that brings the slot housed portions (30,32) on both sides closer to each other is not necessary, or the amount of such deformation is small. Thus, it is possible to suppress the insertion load of inserting the coils (16) into the slots (24) in mounting the coil assembly (40) to the stator core (14).

[11] The stator assembly apparatus (10) described in [10], in which the pusher (70) includes a roller (74) that contacts the coil end portions (34,36) of the coils (16).

The present international application claims priority to Japanese Patent Application No. 2014-117144 filed Jun. 5, 2014, the entire contents of which are incorporated herein.