Using ribs in charger to dissipate heat generated by charging circuit

• US 9,728,984 B2
• Filed: 06/06/2014
• Issued: 08/08/2017
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Ogura, Hironori
• Primary Examiner(s): Levin, Naum B
• Application Number:
  US14/298,244
• Publication Number:
  US 20140375269A1
• Time in Patent Office: 1,159 Days
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H05K 7/20409 Outer radiating structures on heat dissipating housings, e.g. fins integrated with the housing
• CPC Class Codes: H05K 7/20436 Inner thermal coupling elements in heat dissipating housings, e.g. protrusions or depressions integrally formed in the housing

Abstract

An insulation rib is provided above a charging circuit and a plurality of heat radiation ribs are provided on the left side of the charging circuit. A space part is formed by the insulation rib. Little of the heat generated by the charging circuit is transferred to an upper sidewall portion of a case main body portion due to a heat insulation effect of the space part. Further, heat generated by the charging circuit is likely to be transferred to a left sidewall portion of the case main body portion due to a high heat dissipation effect of the heat radiation ribs. In this way, the generation of locally heated areas in the case main body portion can be reduced through balancing of the flow of heat generated by the charging circuit.

Claims

1. A charger for charging a battery pack, comprising a charging circuit inside a main body case thereof, wherein,

a plurality of heat radiation ribs lying parallel to each other are provided inside the main body case and on a lateral side of the charging circuit for dissipating heat generated by the charging circuit;

an insulation rib is disposed between the charging circuit and a sidewall where a rise in temperature caused by heat generated by the charging circuit is high,

the insulation rib is provided with a space part from an upper sidewall portion having low thermal conductivity in order to restrict heat transfer to the upper side wall portion, and

the main body case includes a case main body portion and a case bottom portion, the insulation rib directly contacting the case main body portion at two locations and extending toward the case bottom portion, and the space part being enclosed by the insulation rib and the upper sidewall portion.

2. The charger according to claim 1, wherein the plurality of heat radiation ribs extend from an inner surface of a sidewall of the main body case towards an inner side of the main body case.

3. The charger according to claim 1, wherein the plurality of heat radiation ribs are disposed in an area where a rise in temperature caused by heat generated by the charging circuit is low.

4. The charger according to claim 1, wherein the main body case is comprised of a material and the plurality of heat radiation ribs are integrally molded with the main body case using the material of the main body case.

5. The charger according to claim 1, wherein:

the case main body portion including a battery-mounting portion for mounting the battery pack on a front side thereof and an opening on a rear side thereof;

the main body case is configured such that the opening of the case main body portion is covered and joined by the case bottom portion; and

the plurality of heat radiation ribs extend from the front side of the case main body portion toward the opening of the rear side of the case main body portion.

6. The charger according to claim 1, wherein the main body case is configured to be tightly sealed.

7. The charger according to claim 1, wherein the plurality of heat radiation ribs are made from metal.

8. The charger according to claim 1, wherein the insulation rib has a first end and a second end, the first end directly contacting a sidewall portion of the main body case at a first location and the second end directly contacting a case bottom portion of the main body case at a second location that is different from the first location so as to enclose the space part between the insulation rib and the upper sidewall portion.

9. An electric device comprising:

a charging circuit inside a main body case thereof,

wherein;

a plurality of heat radiation ribs lying parallel to each other are provided inside the main body case and on a lateral side of the charging circuit for absorbing heat generated by the charging circuit and dissipating the heat to the outside of the main body case,

an insulation rib is disposed between the charging circuit and a sidewall where a rise in temperature caused by heat generated by the charging circuit is high,

the insulation rib is provided with a space part from an upper sidewall portion having low thermal conductivity in order to restrict heat transfer to the upper side wall portion, and

the main body case includes a case main body portion and a case bottom portion, the insulation rib directly contacting the case main body portion at two locations and extending toward the case bottom portion, and the space part being enclosed by the insulation rib and the upper sidewall portion.