Direct drive roller motor
AssigneePacific Scientific Company
InventorsBradley A. Trago, Richard Nelson, William T. Fejes, Jr.
Life of this patent
Estimating the term…
Abstract
A direct drive roller motor for use in a belt drive system includes a brushless DC motor that has an external rotor that functions as a direct drive roller. The motor has stator coils mounted on a stator shaft that is physically and thermally coupled at both ends thereof to a support structure which provides in addition to support, a function of dissipating thermal energy generated by the i2R losses of the stator coils and the magnetic core losses of the stator.
Claims11
A direct drive external rotor DC motor for use in driving a belt carried by an external rotor, the motor comprising:
- a high thermal conductivity nonrotatable stator support shaft having a stator mounted thereon, the stator support shaft secured at either end thereof in a thermally conductive manner to a heat dissipating motor support structure;
- the external rotor including a cylindrical rotor housing surrounding the stator and mounted for rotation on the stator shaft, the cylindrical rotor housing acting as a drive roller to propel the belt carried by the external rotor cylindrical rotor housing;
- and
- the cylindrical rotor housing having internally secured thereto for rotation therewith an annular permanent magnetic structure that cooperates with a rotating magnetic field in the stator to generate a drive torque in the external rotor/permanent magnetic structure to thereby propel the belt;
- wherein thermal energy defined by the i2R losses in stator coils and the magnetic core loss of the stator is thermally conducted via the stator support shaft into the motor support structure to be dissipated therefrom thereby enhancing the DC motor operating efficiency.
A low speed, high torque, direct drive external roller rotor DC motor for use in driving a belt carried by the external rotor, the DC motor including in combination:
- an external roller rotor including an elongated cylindrical housing having a length that is at least as long as the width of the belt to be driven;
- the cylindrical external roller rotor housing having integrally secured internal thereto at one end thereof an annular magnetic structure that cooperates with a rotating magnetic field in a stator to produce a torque in the rotor, the stator being mounted on a high thermally conductivity stator shaft that extends through and beyond ends of the cylindrical rotor housing, the stator shaft being thermally and physically coupled to a heat dissipating support structure for thermally conducting thermal energy from the stator to the dissipating support structure;
- and
- the cylindrical external roller housing being mounted for rotation on bearings adjacent ends of the roller housing, the bearings being carried by the thermally conductive stator shaft.
Dependencies are inferred from the claim text.