Stator for rotary electric machine and method for manufacturing the stator
Provided is a stator for a rotary electric machine, capable of reducing a space on an end surface of a stator core on an inner diameter side to reduce a size in an axial direction to realize a compact size by maintaining an insulating distance corresponding to a potential difference. In the stator for a rotary electric machine according to the present invention, a coil portion includes a coil main-body portion ( 21 ) and a second connecting wire ( 23 ). The second connecting wire ( 23 ) includes a first bent portion ( 24 ) and a second connecting-wire end portion ( 23 A). The second connecting wire ( 23 ) is configured so that a differential value of a length z in the axial direction of the stator to a length r in the radial direction of the stator is Δz/Δr≧0.
1. A stator for a rotary electric machine, comprising:
a stator core having a hollow cylindrical shape, including a plurality of slots formed along a circumferential direction by a plurality of teeth, each having a distal end portion projecting to an inner diameter side; and
a stator winding provided to the stator core, including a plurality of coil portions, each including a conductor wound around each tooth of the plurality of teeth, electrically connected to each other through terminal members provided on an outer diameter side of an end surface of the stator core, wherein:
each coil portion of the plurality of coil portions includes: a coil main-body portion; a first connecting wire drawn from an outermost diameter portion of the coil main-body portion; and a second connecting wire drawn from an innermost diameter portion of the coil main-body portion;
the first connecting wire includes a first connecting-wire end portion connected to one terminal-member end portion of a corresponding one of the terminal members;
the second connecting wire includes a first bent portion formed by bending the second connecting wire outward in a radial direction of the stator core and a second connecting-wire end portion connected to another terminal-member end portion of the corresponding one of the terminal members; and
the second connecting wire is configured so that a differential value of a length z in an axial direction of the stator, provided that an axially outward direction is a +-direction, to a length r in a radial direction of the stator, provided that a radially outward direction is a +-direction, is Δz/Δr>0,
wherein an electric field intensity between the second connecting wire and a coil end of a coil main-body portion proportionally increases toward the outer side in the radial direction within a region of the coil main-body portion,
wherein the second connecting wire has a linearly inclined portion extending from the first bent portion to a second bent portion located at the second connecting-wire end portion, the linear inclined portion extending over the entire axial direction of the coil main-body portion.
2. The stator for a rotary electric machine according to claim 1 , wherein:
the plurality of coil portions in the same phase are connected in parallel to each other through the terminal members; and
the each coil portion of the plurality of coil portions is formed by spirally winding the conductor around a corresponding one of the plurality of teeth in a single layer.
3. The stator for a rotary electric machine according to claim 1 , wherein the conductor has a rectangular sectional shape and is wound with one of short sides of a cross section of the conductor being located on an inner side so that a pair of long sides becomes vertical to an axis of winding.
4. The stator for a rotary electric machine according to claim 1 , wherein the first bent portion of the second connecting wire is formed at a position away from an outermost circumferential surface of the coil main-body portion in the radial direction and is formed at a position lower than a second bonded portion, in which the second connecting-wire end portion of the second connecting wire and a corresponding one of the terminal-member end portions of the terminal members are bonded, based on the end surface of the stator core as a reference.
5. The stator for a rotary electric machine according to claim 1 , wherein the first connecting wire extends outward along an axial direction of the stator core and has a crank-like shape with the first bent portion and the second bent portion formed in a middle part.
6. The stator for a rotary electric machine according to claim 1 , wherein the first connecting-wire end portion, the second connecting-wire end portion, and both the terminal-member end portions of each of the terminal members all extend along the axial direction of the stator core.
7. The stator for a rotary electric machine according to claim 1 , wherein a first bonded portion, in which the first connecting-wire end portion of the first connecting wire and the terminal-member end portions of each of the terminal members are bonded, and a second bonded portion, in which the second connecting-wire end portion of the second connecting wire and the terminal-member end portions of each of the terminal members are bonded, are located on a circumference.