Liquid cooled electrical machine with coolant flow control

摘要

An electric machine has a housing 5 carrying cast ribs 19 which define coolant channels and a partition wall 29 on the external side of which electronic/electrical component requiring cooling are mounted, an injection-moulded plastics ring 101 being supported on ledges 25 so as to define with the wall 29 and the end wall of the sleeve surrounding the stator (when installed), two pairs of coolant flow chambers extending around the internal circumference of the housing. The insert is of tapered form and the height of the ledges 25 with respect to the wall 29 is such as to cause the chamber pairs to taper such that a generally uniform rate of transfer of heat from portions of the machine to the coolant is achieved by the varying velocity of liquid though the chambers (see also fig 6). The insert has fluid inlet and outlet areas 107, 109 and two spacers 117 on the side facing wall 29 in conjunction with a plurality of spacers 117 on the side facing the stator sleeve support the insert such that the outlet 109 is positioned midway between the stator surface and wall 29 to allow coolant entering at 107 and flowing along the tapered channel between the insert and wall 29 to pass into the tapering channel between the insert and the stator sleeve where it is distributed to the channels formed between the ribs to flow axially along the machine. A cast-in structure may be substituted for the removable insert. Undulations on the wall 29 and/or the facing surface of the insert create turbulence to improve heat transfer. The ribs 19 are of different lengths so as to produce a circumferential arranged outlet chamber which also tapers at the other axial end of the machine when the housing closure is applied (see fig 7). A seal arrangement F for the housing closure is also disclosed (figs 10, 11).