Today the U.S. Patent and Trademark Office officially granted Apple a patent that’s titled “Electric Motor with Bar Wound Stator and End Turn Cooling.” Although the patent never clearly identifies the electric motor is specifically for vehicles, an article from Green Car Congress reveals GM study that discusses “Bar Wound Stators” in relation to electric-vehicles.
Apple’s granted patent lists Dillon Thomasson as one of the inventors. Thomasson is currently the R&D Manager, Actuation Systems in Apple’s Special Products Group where Project Titan resides. His previous employer was General Dynamics, a company that makes Gulfstream jets to nuclear-powered submarines and electric and hybrid electric vehicles.
Notice: Unless you’re an engineer or someone in the field of electric vehicles, Apple’s patent could be a difficult read.
With that said, Apple notes in their patent background that electric motor designs typically include a stator and a rotor. The stator is an annular structure that is fixed in a housing. The rotor is positioned within the stator along an axis and is supported with respect to the housing such that it is able to rotate relative to the stator. In some electric motor designs, permanent magnets are connected to the rotor, and windings are connected to the stator. The windings are energized to induce rotation of the rotor with respect to the stator in response to interaction of the magnetic fields created by energization of the phase windings with the permanent magnets.
The stator windings may be of the wire-wound type or of the bar-wound type. Wire-wound windings include bundles of conductors that are wrapped around stator teeth of the stator and disposed within the slots of the stator. Bar-wound windings include rigid bars, typically formed from copper, that are disposed within the slots of the stator. Both types of windings include end turns, which are portions of the windings located at the ends of the stator to interconnect portions of the windings that are located in different slots.
Apple’s patent covers an electric motor that includes a stator body that defines slots. Winding bars are each disposed in one of the slots defined by the stator body. An end turn ring has an upper ring surface and a lower ring surface, and includes bus bars that are arranged in a circular array. Each bus bar of the bus bars has a first end portion that is connected to one of the winding bars and a second end portion that is connected to one of the winding bars. The first end portion has a lower bar surface that defines part of the lower ring surface. The second end portion has an upper bar surface that defines part of the upper ring surface. A cooling structure is disposed in a thermally conductive relationship with at least one of the upper ring surfaces or the lower ring surfaces for receiving heat from the end turn ring.
Another aspect of the disclosed embodiments is an electric motor that includes a stator body that defines slots. The electric motor also includes winding bars that are each disposed in one of the slots defined by the stator body. An end turn assembly has an upper surface and a lower surface, and is connected to the winding bars. A cooling structure has a first portion that is in a thermally conductive relationship with the lower surface of the end turn assembly and a second portion that is in a thermally conductive relationship with the upper surface of the end turn assembly.
Another aspect of the disclosed embodiments is a three-phase electric motor that includes a stator body that defines slots, an upper end turn assembly and a lower end turn assembly each having bus bars that are arranged in a circular array, and winding bars. The winding bars are each disposed in one of the slots defined by the stator body. The winding bars are straight and each extend from one of the bus bars of the upper end turn assembly to one of the bus bars of the lower end turn assembly.
Apple’s patent FIG. 1 below is a side cross-section view of an electric motor; FIG. 2 is an exploded view showing an upper end turn assembly, phase windings, and a stator of the electric motor of FIG. 1; FIG. 8 is a perspective view showing an annular cooling manifold.
For more details, review Apple’s granted patent 11,381,126.
Earlier today Patently Apple posted a report titled “Apple wins a patent for advanced energy-absorbing safety devices to control motion of Seating Systems in future Autonomous Vehicles.” Once again, Volkswagen’s CEO stating that Apple’s interesting in electric vehicles is limited to software seems to be out to lunch, as the design of an electric motor is far from being software.
