POWER TOOL

• US 20090245958A1
• Filed: 03/27/2009
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Johnson Electric International AG (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA (Johnson Electric Holdings Limited)
• Inventors: LIU, Alloys J., LAU, James Ching Sik, JIN, Chang Lin, WONG, Duncan Yiu Lung
• Granted Patent: US 9,132,542 B2
• Time in Patent Office: Days
• US Class Current: 408/125
• CPC Class Codes: B25F 5/008 Cooling means
• CPC Class Codes: Y10T 408/655 with specific Tool structure

Abstract

An electric drill has a handle, a body and a drill chuck. The handle is provided with a battery and a switch. The body comprising a shell, a motor fixed in the shell and an impeller fixed to an axle or shaft of the motor. The shell is provided with a plurality of air outlets at a position corresponding to the impeller, the impeller being able to rotate with the axle of the motor to produce an air current to cool the motor. An enclosure of the battery is provided with a plurality of through holes. An air current channel is formed inside the handle and the body and connected to the environment via the through holes of the battery enclosure. A heat dissipating device is located in the air current channel and contacts the switch. A part of the cooling air current passes through the air current channel to cool the battery before getting to the motor. Thus, a part of the cooling air current can cool the battery and the switch before cooling the motor, so as to prevent the battery and the switch from overheating and shortening their service life.

Claims

1. A power tool comprising a handle and a body, one end of the handle being provided with a battery, the body comprising a shell, a motor fixed in the shell and an impeller fixed to an axle of the motor, the shell having a plurality of air outlets at a position corresponding to the impeller, the impeller comprising a plurality of vanes rotating with the axle of the motor to produce an air current to cool the motor, wherein an enclosure of the battery is provided with a plurality of through holes;

an air current channel is formed inside the handle and the body, and connected to the environment via the through holes of the enclosure of the battery; and

a part of the cooling air current passes through the air current channel to cool the battery before reaching the motor.

2. The power tool of claim 1, further comprising a switch provided inside the handle and a heat dissipating device fixed to the switch for absorbing the heat produced by the switch;

the heat dissipating device is located at the air current channel, such that the air current is capable of cooling the heat dissipating device.

3. The power tool of claim 2, wherein the heat dissipating device comprises a base in contact with the switch and a plurality of fins extending from the base, and any two adjacent fins are spaced from each other to form a passageway there between.

4. The power tool of claim 1, further comprising a vacuum pump located at the air current channel.

5. The power tool of claim 1, wherein the motor has a housing, and the impeller has a flange, the flange cooperating with an inner side of the housing to form a partition shield to prevent the air current at one side of the partition shield adjacent to the air outlets from flowing to the air channel.

6. The power tool of claim 1, wherein a circular projecting rib is formed on an inner surface of the shell, and the impeller has a flange, the flange cooperating with the circular projecting rib to form a partition shield to prevent the air current at one side of the partition shield adjacent to the air outlets from flowing into the air channel.

7. The power tool of claim 1, wherein a plurality of air inlets are provided in the shell at a position adjacent to the motor.

8. The power tool of claim 7, wherein the motor comprises an armature and a number of brushes;

the impeller is axially located between the armature and the brushes;

the air current entering from the air inlets of the shell can cool the armature, and the air current entering from the through holes of the enclosure of the battery and passing through the air current channel can cool the brushes.

9. The power tool of claim 1, wherein the power tool is an electric drill and has a drill chuck.