Stator of rotating electrical machine
A stator for a rotating electrical machine includes a stator core, a stator winding disposed on or in the stator core, and an annular resinous seal which covers an axial end portion of a coil end of the stator winding. The resinous seal has an inner circumferential surface which is shaped to have a first inner diameter close to the stator core and a second inner diameter farther away from the stator core. The first inner diameter is selected to be smaller than the second inner diameter. This ensures the stability of electrical insulation of the stator winding.
1 . A stator for a rotating electrical machine comprising:
a stator core;
a stator winding which is disposed on or in the stator core and has a coil end exposed outside an end of the stator core; and
a resinous seal which is in an annular shape and covers an axial end portion of the coil end with an insulating resin,
the resinous seal has an inner circumferential surface facing radially inward thereof, the inner circumferential surface being shaped to have a first inner diameter close to the stator core and a second inner diameter farther away from the stator core, the first inner diameter being smaller than the second inner diameter, wherein
the stator is disposed in a rotating electrical machine, an axis of the rotating electrical machine being oriented in a horizontal direction, the coil end of the stator being cooled by a cooling medium delivered from a position vertically above the coil end to the coil end,
the inner circumferential surface of the resinous seal is inclined such that it slopes radially inward relative to a center axis of the stator core from a first edge of the resinous seal to a second edge of the resinous seal, the first edge being farther from the stator core than the second edge,
the resinous seal has an outer surface facing away from the stator core, the outer surface having at least one of a protrusion and a recess serving as a heat dissipator, and
the protrusion or the recess serving as the heat dissipator being positioned in a path of the cooling medium,
an outer circumferential surface of the resinous seal is inclined such that it slopes radially outward relative to a center axis of the stator core from a third edge of the resinous seal to a fourth edge of the resinous seal, the third edge being farther from the stator core than fourth edge,
the outer circumferential surface serves to direct the cooling medium toward the protrusion or the recess serving as the heat dissipator,
the resinous seal and the stator core define therebetween the cooling path into which the cooling medium enters from above the stator to cool portions of the stator winding which are exposed to the cooling path, and
the inner circumferential surface of the resinous seal leads a portion of the cooling medium from the cooling path between the resinous seal and the stator core to flow along the inner circumferential surface and to redirect toward the protrusion or the recess serving as the heat dissipator located on the outer surface of the resinous seal.
2 . The stator as set forth in claim 1 , wherein the resinous seal has an outer circumferential surface facing radially outward thereof, the outer circumferential surface being shaped to have a first outer diameter close to the stator core and a second outer diameter farther away from the stator core, the first outer diameter being larger than the second outer diameter.
3 . The stator as set forth in claim 1 , wherein the resinous seal has an end surface which faces the stator core and has protrusions formed on a radially inner edge and a radially outer edge which protrude toward the stator core and extend in a circumferential direction of the resinous seal.
4 . The stator as set forth in claim 1 , further comprising a bus bar which connects with the coil end of the stator winding and is arranged to face the coil end in a radial direction of the stator winding, and
the resinous seal is configured to have a bus bar-sealing portion which covers the coil end and the bus bar using the insulating resin wherein
the protrusion or the recess serving as the heat dissipator is formed in or on an outer surface of the bus bar-sealing portion.
5 . The stator as set forth in claim 1 , wherein the inner circumferential surface of the resinous seal is shaped to have formed thereon a plurality of protrusions which bulge radially inward and are arranged at a given interval away from each other in the circumferential direction of the resinous seal.
6 . The stator as set forth in claim 1 , wherein the inner circumferential surface of the resinous seal is formed in a wave-shape with curved concave and convex portions which are arranged alternately.
7 . The stator as set forth in claim 1 , wherein
the stator defines a first cooling path between the resinous seal and the stator core through which cooling medium flows to cool exposed portions of the stator winding, and a second cooling path along the outer surface of the resinous seal where the heat dissipator is positioned, and
the inner circumferential surface of the resinous seal redirects a portion of the cooling medium from the first cooling path to the second cooling path.
8 . The stator as set forth in claim 1 , wherein the resinous seal has an end surface facing the stator core and has protrusions formed on a radially inner edge and a radially outer edge which protrude toward the stator core, the protrusions extending axially beyond portions of the stator winding that contact the resinous seal.