Brushless DC motors with remote Hall sensing and methods of making the same

A brushless DC motor apparatus, comprising:

• a housing;
• a stator assembly coupled to the housing,the stator assembly having a support and windings coupled to the support;
• a magnetic rotor assembly rotatably coupled to the housing, the magnetic rotor assembly being configured to rotate within the housing in response to electric currents through the windings;
• and
• position sensors which are configured to provide position signals identifying angular position of the magnetic rotor assembly relative to the stator assembly, each position sensor including (i) a Hall-effect sensor disposed distally from the windings, and (ii) means for conducting a magnetic field from a location adjacent to the windings to a location adjacent to the Hall-effect sensor, wherein the windings of the stator assembly are configured to operate at a
• maximum temperature which is greater than 150 degrees Celsius, and wherein the Hall effect sensors of the position sensors are configured to operate at a maximum temperature which is less than 150 degrees Celsius.

A DC motor system, comprising:

• an interface;
• a brushless DC motor apparatus which includes:
• a housing;
• a stator assembly coupled to the housing, the stator assembly having a support and windings coupled to the support,
• a magnetic rotor assembly rotatably coupled to the housing, the magnetic rotor assembly being configured to rotate within the housing in response to electric currents through the windings, and
• position sensors which are configured to provide position signals identifying angular position of the magnetic rotor assembly relative to the stator assembly, each position sensor including (i) a Hall-effect sensor disposed distally from the windings, and (ii) magnetic circuit members having first end portions adjacent to the windings and second end portions adjacent to the Hall-effect sensor,
• wherein the windings of the stator assembly are configured to operate at a maximum temperature which is greater than 150 degrees Celsius, and wherein the Hall-effect sensors of the position sensors are configured to operate at a maximum temperature which is less than 150 degrees Celsius;
• and
• a controller coupled to the interface, the wind ings of the stator assembly and the position sensors, the controller being configured to receive the position signals provided by the position sensors and generate the electric currents through the windings in response to commands from the interface.

A method for manufacturing a brushless DC motor apparatus, the method comprising:

• coupling a stator assembly to a housing, the stator assembly having a support and wind ings supported by the support;
• installing position sensors adjacent to the stator assembly, the position sensors being configured to provide position signals identifying angular position of a magnetic rotor assembly relative to the stator assembly, each position sensor including (i) a Hall effect sensor disposed distally from the windings, and (ii) magnetic circuit members having first end portions adjacent to the windings and second end portions adjacent to the Hall-effect sensor;
• and
• rotatably coupling the magnetic rotor assembly to the housing, the magnetic rotor assembly being configured to rotate within the housing in response to electric currents through the windings,
• wherein the windings of the stator assembly are configured to operate at a maximum temperature which is greater than 150 degrees Celsius, and wherein the Hall-effect sensors of the position sensors are configured to operate at a maximum temperature which is less than 150 degrees Celsius.