MOTOR-DRIVE UNIT HAVING HEAT RADIATOR

• US 20140198455A1
• Filed: 01/14/2014
• Published: 07/17/2014
• Est. Priority Date: 01/15/2013
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Inaba, Kiichi, Masuda, Naoki
• Granted Patent: US 9,155,231 B2
• Time in Patent Office: Days
• US Class Current: 361/720
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: H02M 7/00 Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
• CPC Class Codes: H05K 7/20845 for automotive electronic casings H05K7/2089 takes precedence
• CPC Class Codes: H05K 7/2089 for power electronics, e.g. for inverters for controlling motor
• CPC Class Codes: H05K 7/209 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20909 takes precedence

Abstract

A compact motor-drive unit wherein each component can be stably fixed to the unit. A motor-drive unit has a plurality of substrates each having a circuit for driving a motor; semiconductor devices mounted on the respective substrates; at least one smoothing capacitor mounted on at least one of the substrates; and a heat radiator having a heat-transferring surface adjacent to the semiconductors. The smoothing capacitor is positioned within a swept area formed by moving the first substrate arranged generally parallel to a base surface, in a counter-front direction, so that the smoothing capacitor is separated from the first substrate.

Claims

1. A motor-drive unit comprising:

a first substrate and a second substrate wherein a circuit for driving a motor is divided and divided sections of the circuit are formed on the first and second substrates;

a connecting part which connects the first and second substrates so that the first and second substrates intersect with each other;

a semiconductor device mounted on each of the first and second substrates;

a heat radiator having a first heat-transferring surface adjacent to the semiconductor device mounted on the first substrate; and

a capacitor positioned within a swept area formed by moving the first substrate in a direction perpendicular to the first heat-transferring surface, the capacitor being separated from the first substrate.

2. The motor-drive unit as set forth in claim 1, wherein the capacitor is a screw-fastening-type capacitor which is fastened to a first conductive arm member extending from the first substrate by means of a screw.

3. The motor-drive unit as set forth in claim 1, wherein the capacitor is mounted on a capacitor substrate attached to a second conductive arm member extending from the first substrate.

4. The motor-drive unit as set forth in claim 1, wherein the capacitor is mounted on an extended portion formed by extending the second substrate in a direction perpendicular to the first substrate.

5. The motor-drive unit as set forth in claim 1, wherein a part of the heat radiator has a projecting portion extending in a direction perpendicular to the first heat-transferring surface, and the semiconductor device is attached to the projecting portion.

6. The motor-drive unit as set forth in claim 1, wherein semiconductor devices are positioned adjacent to at least two heat-transferring surfaces having different surface directions.

7. The motor-drive unit as set forth in claim 6, wherein the heat radiator has a plurality of heat-releasing fins extending parallel to each other at an inclined angle relative to the first heat-transferring surface.

8. The motor-drive unit as set forth in claim 6, wherein the heat radiator has a plurality of heat-releasing fins including fins extending perpendicular to one of the at least two heat-transferring surfaces and including fins extending perpendicular to the other of the at least two heat-transferring surfaces.