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US 8,803,377 B2Granted
Power tool
AssigneeJohnson Electric S.A.
InventorJames Ching-Sik Lau
Life of this patent
Estimating the term…
Abstract
A power tool has a casing and a motor assembly installed within the casing. The motor assembly comprises a motor, a heat dissipation device, a fan and a guiding member. The motor has a stator and a rotor. The heat dissipation device has an annular heat absorbing section which is fitted to a housing of the stator and a plurality of fins extending from the heat absorbing section for dissipating heat. Air flow generated by the fan is guided to the fins of the heat dissipation device by the guiding member to cool the motor.
Claims11
A motor assembly comprising:
- a motor comprising a stator, a rotor installed inside the stator, and an airflow passage formed inside the motor, the airflow passage having two axial ends both being open to communicate with outside of the motor;
- a heat dissipation device disposed on a radially outer surface of the stator for absorbing heat from the stator,
- a fan attached to the rotor and located outside of the motor adjacent to one axial open end of the motor for generating an airflow to pass through the airflow passage inside the motor;
- and
- a guiding member arranged at one end of the motor and configured to guide the airflow generated by the fan to the heat dissipation device on the radially outer surface of the stator,
- wherein the airflow generated by the fan enters into the airflow passage inside the motor from outside of the motor via the other one axial open end of the motor away from the fan and exits the airflow passage via the one axial open end of the motor adjacent the fan, the airflow reaches the fan located outside of the motor after exiting the airflow passage inside the motor and is then guided to the heat dissipation device by the guiding member.
3 more elements
A power tool comprising:
- a casing with an inlet and an outlet;
- and
- a motor assembly installed within the casing, the motor assembly comprising a motor with a ring, a heat dissipation device, and a fan, an air passage being formed between the casing and the ring,
- the motor comprising a stator and a rotor having a shaft;
- the heat dissipation device being arranged on a radially outer surface of the ring for absorbing heat from the motor, the heat dissipation device being disposed at the air passage,
- the fan being attached on the shaft of the rotor,
- wherein air flow generated by the fan enters the casing via the inlet and then flows to the outlet through the air passage and heat dissipation device to thereby cool the motor, and
- wherein the inlet is defined at an axial end of the casing adjacent to one axial end of the motor, and the outlet is defined at a portion of the casing adjacent to the other axial end of the motor.
5 more elements
Dependencies are inferred from the claim text.