Power tool

• US 9,132,542 B2
• Filed: 03/27/2009
• Issued: 09/15/2015
• 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: Lau, James Ching Sik, Wong, Duncan Yiu Lung, Jin, Chang Lin, Liu, Aloys J.
• Primary Examiner(s): CHUKWURAH, NATHANIEL C
• Application Number:
  US12/412,833
• Publication Number:
  US 20090245958A1
• Time in Patent Office: 2,363 Days
• Field of Search: 173/48, 173/117, 173/170, 173/171, 173/216, 173/217, 310/47, 310/50, 310/64
• US Class Current: 1/1
• CPC Class Codes: B25F 5/008 Cooling means
• CPC Class Codes: Y10T 408/655 with specific Tool structure

Abstract

A power tool has a handle and a body. The handle is provided with a battery. A motor is fixed inside a shell of the tool. An impeller is driven by the motor to create an air current to cool the motor and the battery. A plurality of air outlets are formed in the shell at a position corresponding to the impeller. An air current channel is formed inside the handle and the body and connected to the environment via holes in an enclosure of the battery. A part of the air current passes through the air current channel to cool the battery before reaching the motor.

Claims

1. A power tool comprising:

a handle having a first end, a second end, and an air current channel formed between the first and second ends;

an enclosure at the first end of said handle and having a plurality of through holes;

a battery disposed in said enclosure;

a shell connected to the second end of said handle, in communication with the air current channel in said handle, and having an air inlet and an air outlet;

a chuck connected to the shell, the air inlet located closer to the chuck than the air outlet;

a motor in said shell having a first end and a second end opposite to each other, the second end of said motor located closer to the air inlet of the shell than the first end of said motor, the air outlet being disposed between the air inlet and the first end of the motor; and

an impeller mounted to an axle of said motor and disposed between the first and second ends of said motor, the impeller having a first axial end and a second axial end opposite to each other, and a plurality of vanes between said first and second axial ends, the vanes radially facing the outlet of the shell,

wherein the plurality of vanes of said impeller rotating with the axle of said motor generates a first air current entering said enclosure via the plurality of through holes, past said battery and the air current channel in said handle, flowing through the first end of said motor in said shell, reaching the impeller from the first axial end thereof, and exiting said shell via the air outlet, and a second air current entering said shell via the air inlet, flowing through the second end of said motor, and then reaching the impeller from the second axial end thereof and exiting said shell via the air outlet.

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 first 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 in a direction perpendicular to the air current channel, and any two adjacent fins are spaced from each other to form a passageway there between, the passageway parallel to the air current channel to allow the first air current to pass through the passageway in a direction parallel to the air current channel.

4. The power tool of claim 1, further comprising a vacuum pump adjacent said motor, the first air current passing through the vacuum pump before reaching the first end of said motor.

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 outlet from flowing to an opposite side of the partition shield away from the air outlet.

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 outlet from flowing back to an opposite side of the partition shield away from the air outlet.

7. The power tool of claim 1, wherein the motor comprises an armature and a number of brushes;

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

the second air current entering from the air inlet of the shell can cool the armature, and the first air current entering from the through holes of the enclosure and passing through the air current channel can cool the brushes.

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

10. The power tool of claim 1, wherein the impeller is located between the first and second ends of said motor and radially faces the outlet of said shell.

9. A power tool comprising:

a handle, one end of the handle being provided with an enclosure, the enclosure defining a plurality of through holes;

a battery disposed in said enclosure;

a body comprising a shell connected with the handle, the shell defining an air inlet;

a motor fixed in the shell, the motor having a first end and a second end opposite to each other; and

an impeller fixed to an axle of the motor and disposed between the first and second ends of said motor, the impeller comprising a plurality of vanes which is rotatable with the axle of the motor to produce an air current to cool the motor,

wherein;

the motor comprises an armature and a number of brushes, the impeller being axially located between the armature and the brushes;

the shell defines an air outlet at a position radially facing the impeller, the vanes of the impeller extending toward the air outlet in radial directions of the impeller,

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

a first part of the air current generated by the impeller fixed to the axle of the motor in the shell enters into the enclosure via the through holes of the enclosure in which the battery is disposed and passes through the air current channel before reaching the motor, said first part of the air current flowing from outside the enclosure, past the battery, the air current channel inside the handle and the brushes of the motor, and then to the impeller to thereafter exit the power tool via the outlet, and

a second part of the air current enters from the air inlets of the shell and passes through the armature of the motor, and then to the impeller.