Power tool including hybrid electric motor design

• US 8,508,084 B2
• Filed: 04/03/2009
• Issued: 08/13/2013
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: Techtronic Power Tools Technology Limited (Techtronic Industries Company Limited)
• Original Assignee: Techtronic Power Tools Technology Limited (Techtronic Industries Company Limited)
• Inventors: Satterfield, Roger G., Hembroff, Stephen C.
• Primary Examiner(s): Nguyen, Tran
• Assistant Examiner(s): Johnson, Eric
• Application Number:
  US12/417,777
• Publication Number:
  US 20090322166A1
• Time in Patent Office: 1,593 Days
• Field of Search: 310/50, 310/47, 310/249, 310/58, 310 62- 63, 173/217
• US Class Current: 310/50
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence
• CPC Class Codes: H02K 5/145 Fixedly supported brushes or brush holders, e.g. leaf or leaf-mounted brushes
• CPC Class Codes: H02K 5/1672 radially supporting the rotary shaft at both ends of the rotor H02K5/1677 takes precedence
• CPC Class Codes: H02K 7/083 radially supporting the rotary shaft at both ends of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 7/145 Hand-held machine tool
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft

Abstract

An electric motor for use with a power tool includes a motor housing having a first end and an open second end, a first bearing coupled to the first end of the motor housing, a plurality of magnets coupled to the motor housing, and an armature having a first end and a second end. The first end of the armature is rotatably supported by the first bearing. The second end of the armature protrudes from the open second end of the motor housing without being supported by the open second end of the motor housing. The electric motor also includes a second bearing coupled to the second end of the armature. The motor housing is supportable by a first portion of the power tool housing. The second bearing is supportable by a second portion of the power tool housing.

Claims

1. An electric motor for use with a power tool including a power tool housing, the power tool housing including a first portion and a second portion, the electric motor comprising:

a motor housing having a first end and an open second end;

a first bearing coupled to the first end of the motor housing and at least partially disposed within the motor housing;

a plurality of magnets coupled to the motor housing;

an armature having a first end and a second end, the first end of the armature being rotatably supported by the first bearing, the second end of the armature protruding from the open second end of the motor housing without being supported by the open second end of the motor housing;

a second bearing coupled to the second end of the armature;

a brush assembly supportable by the power tool housing and positioned outside the motor housing between the open second end of the motor housing and the second end of the armature; and

a fan coupled for co-rotation with the armature, the fan positioned outside the motor housing between the open second end of the motor housing and the brush assembly;

wherein the fan includes a plurality of blades having respective blade tips that circumscribe an outer diameter of the fan, wherein the outer diameter of the fan is greater than or equal to an outer diameter of the motor housing;

wherein the motor housing is supportable by the first portion of the power tool housing, and wherein the second bearing is captured within a receptacle in the second portion of the power tool housing.

2. The electric motor of claim 1, wherein the brush assembly includes:

a brush holder;

at least one brush supported by the brush holder; and

an electrical lead extending from the at least one brush.

3. The electric motor of claim 2, wherein the armature defines a longitudinal axis, and wherein the electrical lead of the at least one brush extends from the brush holder in a direction substantially normal to the longitudinal axis.

4. The electric motor of claim 2, wherein an outer diameter of the brush holder is at least as large as an outer diameter of the motor housing.

5. The electric motor of claim 1, wherein the first bearing is one of a ball bearing and a sleeve bearing.

6. The electric motor of claim 1, wherein the second bearing is one of a ball bearing and a sleeve bearing.

7. A power tool comprising:

a power tool housing;

a motor housing supported by a first portion of the power tool housing, the motor housing having a first end and an open second end;

a first bearing coupled to the first end of the motor housing and at least partially disposed within the motor housing;

a plurality of magnets coupled to the motor housing;

an armature having a first end and a second end, the first end of the armature being rotatably supported by the first bearing, the second end of the armature protruding from the open second end of the motor housing without being supported by the open second end of the motor housing;

a second bearing coupled to the second end of the armature and captured within a receptacle in a second portion of the power tool housing;

a brush assembly supported by the power tool housing and positioned outside of the motor housing between the open second end of the motor housing and the second end of the armature; and

a fan coupled for co-rotation with the armature, the fan positioned outside the motor housing between the open second end of the motor housing and the brush assembly;

wherein the fan includes a plurality of blades having respective blade tips that circumscribe an outer diameter of the fan, and wherein the outer diameter of the fan is greater than or equal to an outer diameter of the motor housing.

8. The power tool of claim 7, wherein the brush assembly includes:

a brush holder;

at least one brush supported by the brush holder; and

an electrical lead extending from the at least one brush.

9. The power tool of claim 8, wherein the armature defines a longitudinal axis, and wherein the electrical lead of the at least one brush extends from the brush holder in a direction substantially normal to the longitudinal axis.

10. The power tool of claim 8, wherein an outer diameter of the brush holder is at least as large as an outer diameter of the motor housing.

11. The power tool of claim 7, wherein the first bearing is one of a ball bearing and a sleeve bearing.

12. The power tool of claim 7, wherein the second bearing is one of a ball bearing and a sleeve bearing.

13. The power tool of claim 7, wherein the power tool housing includes two interconnected shells, and wherein the receptacle is defined by a combination of the shells.

14. The power tool of claim 13, wherein at least one of the shells includes a plurality of cooling apertures proximate the fan, and wherein the fan is operable to generate an airflow through the motor housing and exhaust the airflow through the cooling apertures.

15. The power tool of claim 13, wherein each of the shells includes a plurality of cooling apertures proximate the fan, and wherein the fan is operable to generate an airflow through the motor housing and exhaust the airflow through the cooling apertures.

16. The power tool of claim 13, wherein the interconnected shells define an interior of the power tool housing, and wherein the fan is directly exposed to the interior of the power tool housing.