Control and power module for driving a brushless motor in a power tool

Patent metadata

Field	Value
Publication number	US-11370100-B2
Application number	US-201916460187-A
Country	US
Kind code	B2
Filing date	Jul 2, 2019
Priority date	Oct 30, 2015
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

A power tool is provided including a motor housing having a substantially-cylindrical main body having an open end and a rear end. A brushless DC motor is provided including a stator assembly received through the open end of the motor housing and secured within the main body of the motor housing. A motor control and power module disposed proximate the rear end of the motor housing includes a printed circuit board (PCB) on which power switch and a controller are mounted. A mounting bracket is secured to the motor housing at the rear end to support the module such that the PCB is substantially parallel to the rear end. The mounting bracket includes a mating portion projecting axially to come to contact with the motor housing around the rear end to structurally support the mounting bracket with respect to the motor housing.

First claim

The invention claimed is:

1. A power tool comprising:
a tool housing;
a motor housing disposed within the tool housing and having a substantially-cylindrical main body having an open end and a rear end at least partially closing the main body disposed opposite the open end;
a brushless DC (BLDC) motor disposed within the motor housing, the motor including: a stator assembly received through the open end of the motor housing and secured within the main body, and a rotor assembly rotatably disposed within the stator assembly;
a motor control and power module disposed proximate the rear end of the motor housing, the motor control and power module comprising a printed circuit board (PCB), a power switch circuit including a plurality of semiconductor switches electrically mounted on the PCB and coupled to the motor, and a controller being a programmable device also mounted on the PCB and configured to output a plurality of drive control signals to operate the plurality of semiconductor switches to supply power from a power source to the motor; and
a mounting bracket secured to the motor housing at the rear end thereof, the mounting bracket supporting the motor control and power module such that the PCB is substantially parallel to the rear end of the motor housing, the mounting bracket comprising a mating portion projecting axially to come to contact with the motor housing around the rear end thereof to structurally support the mounting bracket with respect to the motor housing.

2. The power tool of claim 1 , wherein the mating portion comprises a substantially cylindrical portion arranged to mate around a circumferential portion of the motor housing at or near the rear end of the motor housing.

3. The power tool of claim 2 , wherein the motor housing comprises a plurality of guide rails on its outer surface, and the cylindrical portion comprises a plurality of legs that slidingly mate with the guide rails of the motor housing.

4. The power tool of claim 2 , wherein the mounting bracket further comprises a planar portion extending radially outwardly from the substantially cylindrical portion, and a plurality of mount posts located around the planar portion.

5. The power tool of claim 4 , wherein the plurality of mount posts extends outwardly at an angle from the planar portion.

6. The power tool of claim 5 , wherein the plurality of mount posts is arranged along a circumference having a larger diameter than the substantially cylindrical portion.

7. The power tool of claim 4 , further comprising a rear cover configured to mate with the plurality of mount posts to support the motor control and power module proximate the rear end of the motor housing.

8. The power tool of claim 7 , wherein the power switch circuit comprises a plurality of Insulated-Gate Bipolar Transistors (IGBTs) configured as a three-phase bridge driver circuit, and at least one heat sink mounted on the PCB in thermal communication with the IGBTs, the rear cover and the mounting bracket together defining at least one peripheral opening adjacent the motor control and power module to allow passage of air to the heat sink.

9. The power tool of claim 8 , wherein the at least one heat sink includes a curved surface that substantially covers a side surface and a top surface of the plurality of IGBTs, and a plurality of fins projecting outwardly from the curved surface.

10. The power tool of claim 8 , wherein the motor further comprises a fan rotatably coupled to the rotor assembly generating an airflow path, and the rear end of the motor housing comprises at least one opening to provide fluid communication between the motor fan and the motor control and power module to provide the airflow path through the at least one peripheral opening in contact with the heat sink, through the mounting bracket, and into the motor housing.

11. The power tool of claim 2 , wherein the substantially cylindrical portion is sized to fittingly receive the rear end of the motor housing therein.

12. The power tool of claim 2 , further comprising a plurality of motor terminals axially extending from the stator assembly and protruding through a plurality of openings of the rear end of the motor housing, the plurality of motor terminals being received within the substantially cylindrical portion of the mounting bracket and electrically coupled to the power switch circuit via a plurality of motor wires.

13. The power tool of claim 1 , wherein the mounting bracket comprises wire routing and retention features on an inner portion thereof for receiving motor wires from the motor.

14. The power tool of claim 1 , further comprising at least one battery receptacle accommodated on the tool housing, the battery receptacle being adapted to receive a battery pack having a maximum voltage of at least 60 volts.

15. The power tool of claim 14 , further comprising a battery management module comprising a secondary printed circuit board (PCB) disposed within the tool housing near the battery receptacle and at a distance from the PCB, and a battery-management controller being a programmable device mounted on the secondary PCB, the second controller being configured to receive a signal related to at least one of a temperature or voltage of the battery pack from the battery receptacle and mange an operation of the battery pack accordingly.

16. The power tool of claim 15 , wherein the battery management module is disposed along a plane that is substantially perpendicular to the PCB.

17. The power tool of claim 1 , wherein the motor housing comprises a radially-extending slot formed at or near the rear end thereof, the power tool further comprising a positional sensor board radially received within the slot and a plurality of positional sensors mounted on the positional sensor board.

18. The power tool of claim 17 , wherein the mounting bracket comprises at least one axially-projecting finger arranged to engage an outer end of the positional sensor board to hold the positional sensor board within the slot.

Assignees

• Black & Decker Inc

Inventors

• Palich Andrew M
• Marjomaa Michael R
• Pulley Kevin L
• Smith David J
• Bush Dennis A
• Cherry Mark T
• Eshlemann Scott
• Gottesman Tal

Classifications

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title

• B25F5/02 Primary

  Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} · CPC title

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M10/42

  Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells (H01M10/60 takes precedence) · CPC title