Power tool with substrate having apertures for cooling coils and switching elements

Patent metadata

Field	Value
Publication number	US-9680349-B2
Application number	US-201414186001-A
Country	US
Kind code	B2
Filing date	Feb 21, 2014
Priority date	Feb 27, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

An electric power tool including: a housing; a brushless motor accommodated in the housing; a fan attached to a rotation shaft of the brushless motor; a switching element configured to control the brushless motor; and a substrate on which the switching element is mounted, wherein a first through-hole is provided to a switching element arranged portion of the substrate.

First claim

What is claimed is:

1. An electric power tool comprising:
a housing;
a brushless motor accommodated in the housing;
a fan attached to a rotation shaft of the brushless motor;
a switching element configured to control the brushless motor, the switching element including a body covered by resin; and
a substrate on which the switching element is mounted,
wherein a first through-hole is provided to a switching element arranged portion of the substrate at which the body of the switching element is located,
wherein the substrate is disposed at either of a front side or a rear side of the brushless motor,
wherein the brushless motor includes a plurality of coil slots, and
wherein, when viewed in an axial direction of the brushless motor, the first through-hole is positioned or extends between adjacent coil slots of the brushless motor.

2. The electric power tool according to claim 1 , wherein a portion of an opening of the first through-hole is blocked by the body of the switching element or a first heat radiator which contacts with the body of the switching element.

3. The electric power tool according to claim 1 , wherein a ventilator window is provided to the housing, and
wherein the first through-hole is provided adjacent to the ventilator window and is configured to suck air.

4. The electric power tool according to claim 1 , wherein a windbreak portion is provided in a gap between an inner surface of the housing and an outer peripheral portion of the brushless motor.

5. The electric power tool according to claim 4 , wherein the windbreak portion is a rib or a protrusion which is provided on the inner surface of the housing and protrudes to the gap.

6. The electric power tool according to claim 1 , wherein a second heat radiator is provided to a rear surface of a switching element arranged surface of the substrate, and
wherein the second heat radiator passes through the first through-hole and contacts with the body of the switching element or the first heat radiator contacting with the body of the switching element.

7. The electric power tool according to claim 1 , wherein a second through-hole, which has an opening blocked by the body of the switching element or the first heat radiator contacting with the body of the switching element, is provided to the substrate.

8. The electric power tool according to claim 7 , wherein a second heat radiator is provided to a rear surface of a switching element arranged surface of the substrate, and
wherein the second heat radiator passes through the first and second through-holes and contacts with the switching element or the first heat radiator at two locations.

9. The electric power tool according to claim 1 , wherein the switching element is a surface mounting type switching element.

10. The electric power tool according to claim 1 , wherein a third through-hole, through which the rotation shaft of the brushless motor passes, is provided to the substrate.

11. An electric power tool comprising:
a housing;
a brushless motor accommodated in the housing;
a switching element configured to control the brushless motor, the switching element including a body and a heat radiation plate,
wherein the heat radiation plate includes a first surface that contacts the switching element and a second surface opposite the first surface; and
a substrate on which the switching element is mounted,
wherein a first portion of the second surface of the heat radiation plate contacts with the substrate,
wherein a second portion of the second surface of the heat radiation plate contacts a heat radiation fin such that the heat radiation plate is at least partially sandwiched between the switching element and the heat radiation fin.

12. The electric power tool according to claim 11 , wherein a first through-hole is provided to the substrate, and
wherein the portion of the first surface of the heat radiation plate is exposed through the first-through hole.

13. An electric power tool comprising:
a housing;
a brushless motor accommodated in the housing;
a fan attached to a rotation shaft of the brushless motor;
a switching element configured to control the brushless motor, the switching element including a body covered by resin; and
a substrate on which the switching element is mounted,
wherein a first through-hole is provided to a switching element arranged portion of the substrate at which the body of the switching element is located,
wherein a second heat radiator is provided to a rear surface of a switching element arranged surface of the substrate, and
wherein the second heat radiator passes through the first through-hole and contacts with the body of the switching element or a first heat radiator contacting with the body of the switching element.

Assignees

• Hitachi Koki Kk

Inventors

• Tokairin Junichi
• Sato Naoki
• Ogawa Itsushi

Classifications

• H02K9/22

  by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges · CPC title

• H02K9/00

  Arrangements for cooling or ventilating (channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24) · CPC title

• H02K7/145 Primary

  Hand-held machine tool · CPC title

• B25F5/008

  Cooling means · CPC title

• H02K9/223

  Heat bridges · CPC title