INERTIAL FAN FOR POWER TOOL

• US 20190314968A1
• Filed: 04/05/2019
• Published: 10/17/2019
• Est. Priority Date: 04/16/2018
• Status: Active Grant

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Bailey, Matthew R., Didier, Will
• Granted Patent: US 11,667,021 B2
• Time in Patent Office: Days
• CPC Class Codes: B25C 1/047 Mechanical details
• CPC Class Codes: B25C 1/06 operated by electric power
• CPC Class Codes: B25F 5/008 Cooling means

Abstract

A power tool includes a motor having a motor shaft that rotates about a motor axis in a first rotational direction. The power tool also includes a fan assembly attachable to the motor shaft for rotation in the first rotational direction. The fan assembly includes a fan body and a bearing having a race that is rotatably affixed to the fan body. The race is freely rotatable relative to the motor shaft in the first rotational direction, and fixed against rotation relative to the motor shaft in a second rotational direction opposite the first rotational direction.

Claims

1. A power tool comprising:

a motor having a motor shaft that rotates about a motor axis in a first rotational direction;

a fan assembly attachable to the motor shaft for rotation in the first rotational direction, the fan assembly including

a fan body; and

a bearing having a race that is rotatably affixed to the fan body, the race being freely rotatable relative to the motor shaft in the first rotational direction, and fixed against rotation relative to the motor shaft in a second rotational direction opposite the first rotational direction.

2. The power tool of claim 1, wherein the fan assembly further includes a flywheel rotatably affixed to the fan body.

3. The power tool of claim 2, wherein the race is rotatably affixed to the flywheel.

4. The power tool of claim 1, wherein the bearing is a first bearing and the race is a first race, and the fan assembly further includes a second bearing having a second race that is rotatably affixed to the fan body.

5. The power tool of claim 4, wherein the second race is freely rotatable relative to the motor shaft in each of the first and second rotational directions.

6. The power tool of claim 1, further comprising an energy storage device coupled to the motor shaft and to the fan assembly, the energy storage device being configured to supply torque to the fan assembly upon deactivation of the electric motor.

7. The power tool of claim 1, further comprising an air compression and storage device coupled to the motor shaft, the air compression and storage device being configured to supply an airflow to cool the electric motor upon deactivation of the electric motor.

8. The power tool of claim 1, further comprising an auxiliary fan configured to supply an airflow to cool the electric motor upon deactivation of the electric motor.

9. A method of cooling an electric motor configured for use in a power tool, the electric motor having a motor shaft rotatable about a motor axis, and the power tool further including a fan assembly attachable to the motor shaft, the method comprising:

activating the electric motor to supply torque to the motor shaft;

rotating the motor shaft and the fan assembly about the motor axis, the fan assembly generating an airflow to cool the electric motor; and

deactivating the electric motor to stall rotation of the motor shaft;

wherein the fan assembly continues to rotate about the motor axis to generate the airflow after rotation of the motor shaft has ceased.

10. The method of claim 9, wherein the power tool further comprises an energy storage device coupled to the motor shaft and to the fan assembly, and wherein the method further comprises:

before the step of deactivating the electric motor, supplying torque from the electric motor to the energy storage device to store energy therein; and

after the step of deactivating the electric motor, supplying torque from the energy storage device to the fan assembly to rotate the fan assembly about the motor axis.

11. The method of claim 9, wherein the power tool further comprises an air compression and storage device coupled to the motor shaft, and wherein the method further comprises:

before the step of deactivating the electric motor, supplying torque form the electric motor to the air compression and storage device to compress and store air therein; and

after the step of deactivating the electric motor, releasing the air from the air compression and storage device to generate a secondary airflow to cool the electric motor.

12. The method of claim 9, wherein the power tool further comprises a power source and an auxiliary fan electrically coupled to the power source, and wherein the method further comprises:

after the step of deactivating the electric motor, supplying electrical power from the power source to the auxiliary fan to generate a secondary airflow to cool the electric motor.

13. A power tool comprising:

a motor having a motor shaft that rotates about a motor axis in a first rotational direction;

a fan assembly attachable to the motor shaft for rotation in the first rotational direction, the fan assembly including

a fan body; and

a flywheel rotatably affixed to the fan body;

wherein the fan body and the flywheel are freely rotatable relative to the motor shaft in the first rotational direction, and fixed against rotation relative to the motor shaft in a second rotational direction opposite the first rotational direction.

14. The power tool of claim 13, wherein the fan assembly further includes a bearing having a race that is rotatably affixed to the flywheel, the race being freely rotatable relative to the motor shaft in the first rotational direction, and fixed against rotation relative to the motor shaft in the second rotational direction.

15. The power tool of claim 14, wherein the bearing further includes a cage that supports a plurality of rollers.

16. The power tool of claim 14, wherein the bearing is a first bearing and the race is a first race, and the fan assembly further includes a second bearing having a second race that is rotatably affixed to the flywheel.

17. The power tool of claim 16, wherein the second race is freely rotatable relative to the motor shaft in each of the first and second rotational directions.

18. The power tool of claim 13, further comprising an energy storage device coupled to the motor shaft and to the fan assembly, the energy storage device being configured to supply torque to the fan assembly upon deactivation of the electric motor.

19. The power tool of claim 13, further comprising an air compression and storage device coupled to the motor shaft, the air compression and storage device being configured to supply an airflow to cool the electric motor upon deactivation of the electric motor.

20. The power tool of claim 13, further comprising an auxiliary fan configured to supply an airflow to cool the electric motor upon deactivation of the electric motor.