Brushless DC motor power tool with combined PCB design

Patent metadata

Field	Value
Publication number	US-10530220-B2
Application number	US-201916388422-A
Country	US
Kind code	B2
Filing date	Apr 18, 2019
Priority date	May 24, 2012
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A power tool with a combined printed circuit board (PCB) that reduces internal wiring of the power tool and provides a large amount of air flow to internal components. In some instances, the combined PCB has a surfboard shape and includes a motor control unit and power switching elements (Field Effect Transistors or FETs). The combined surfboard PCB is located above the trigger, but below the motor and drive mechanism. In other instances, the combined PCB has a doughnut shape and is located coaxially with a motor shaft. The combined PCB may be positioned between a doughnut-shaped control PCB and the motor.

First claim

What is claimed is:

1. A power tool comprising:
a housing having a motor housing portion, a handle portion, and a battery interface, wherein the handle portion spacially connects the motor housing portion and the battery interface;
a brushless direct current (DC) motor within the motor housing portion and having a rotor and a stator, wherein the rotor is coupled to a motor shaft arranged to rotate about a longitudinal axis, which extends through the motor shaft, and to produce an output outside of the housing;
a combined printed circuit board (PCB) having a Hall sensor, power switching elements, and a first through-hole, wherein the power switching elements are mounted on the combined PCB in a flat orientation and wherein the longitudinal axis extends through the first through-hole;
a heat sink attached to an end of the brushless DC motor, wherein the heat sink has a second through-hole through which the longitudinal axis extends and wherein the heat sink is located between the brushless DC motor and the combined PCB; and
a control PCB configured to receive motor positional information from the Hall sensor and control the power switching elements to drive the brushless DC motor, wherein the control PCB is located between the handle portion and the battery interface;
wherein the second through-hole is larger than the first through-hole and the Hall sensor is located radially outward of the first through-hole and radially inward of the second through-hole.

2. The power tool of claim 1 , further comprising a cable connector located on the combined PCB, wherein the cable connector is configured to receive a cable that communicatively couples the combined PCB with the control PCB.

3. The power tool of claim 1 , wherein the control PCB includes a processor and a memory.

4. The power tool of claim 1 , further comprising:
a transmission, wherein the motor shaft is coupled to the transmission; and
at least one selected from the group consisting of a chuck and a bit holder that is coupled to an output of the transmission, wherein the longitudinal axis extends through the at least one selected from the group consisting of the chuck and the bit holder, and
wherein the motor shaft is arranged to drive the at least one selected from the group consisting of the chuck and the bit holder via the transmission to produce the output outside of the housing.

5. The power tool of claim 1 , wherein the output outside of the housing is a rotational output.

6. The power tool of claim 1 , wherein the battery interface removably receives and supports a battery pack.

7. The power tool of claim 1 , wherein the motor shaft extends through at least one selected from the group of the first through-hole and the second through-hole.

8. A power tool comprising:
a brushless direct current (DC) motor having a rotor and a stator, wherein the rotor is coupled to a motor shaft to produce a rotational output, wherein the motor shaft is configured to rotate about a longitudinal axis, which extends through the motor shaft;
a transmission coupled to the motor shaft configured to be driven by the rotational output;
a combined printed circuit board (PCB) having a Hall sensor, power switching elements, and a first through-hole, wherein the power switching elements are mounted on the combined PCB in a flat orientation and wherein the longitudinal axis extends through the first through-hole;
a heat sink attached to an end of the brushless DC motor, wherein the heat sink has a second through-hole through which the longitudinal axis extends and wherein the heat sink is located between the brushless DC motor and the combined PCB;
a control PCB configured to receive motor positional information from the Hall sensor and control the power switching elements to drive the brushless DC motor; and
a cable that communicatively couples the combined PCB with the control PCB;
wherein the second through-hole is larger than the first through-hole and the Hall sensor is located radially outward of the first through-hole and radially inward of the second through-hole.

9. The power tool of claim 8 , wherein the control PCB includes a processor and a memory.

10. The power tool of claim 8 ,
wherein at least two of the power switching elements on the combined PCB are located on a first side of a second axis that bisects the first through-hole of the combined PCB and is perpendicular to the longitudinal axis extending through the motor shaft; and
wherein at least two other of the power switching elements on the combined PCB are located on a second side of the second axis that bisects the first through-hole of the combined PCB and is perpendicular to the longitudinal axis extending through the motor shaft.

11. The power tool of claim 8 ,
wherein the combined PCB includes a second Hall sensor and a third Hall sensor, wherein the second Hall sensor and the third Hall sensor are located radially outward of the first through-hole and radially inward of the second through-hole; and
wherein the power switching elements are located on a first face of the combined PCB and the Hall sensor, the second Hall sensor, and the third Hall sensor are located on a second face of the combined PCB.

12. The power tool of claim 8 , wherein the heat sink receives a screw that secures the heat sink between the combined PCB and the brushless DC motor.

13. The power tool of claim 8 , further comprising:
a frame supporting the brushless DC motor, the combined PCB and the heat sink.

14. The power tool of claim 13 , wherein the frame is a housing in which the brushless DC motor, the combined PCB, and the heat sink are located.

15. The power tool of claim 8 , further comprising:
at least one selected from the group consisting of a chuck and a bit holder that is coupled to an output of the transmission, wherein the longitudinal axis extends through the at least one selected from the group consisting of the chuck and the bit holder, and
wherein the motor shaft is arranged to drive the at least one selected from the group consisting of the chuck and the bit holder via the transmission to produce an output outside of the housing.

16. The power tool of claim 8 , wherein the motor shaft extends through at least one selected from the group of the first through-hole and the second through-hole.

17. A power tool comprising:
a frame;
a brushless direct current (DC) motor supported by the frame and having a motor shaft arranged to rotate about a longitudinal axis, which extends through the motor shaft, and to produce a rotational output;
a combined printed circuit board (PCB) having a Hall sensor, power switching elements, and a first through-hole, wherein the longitudinal axis extends through the first through-hole;
a heat sink attached to an end of the brushless DC motor, wherein the heat sink has a second through-hole through which the longitudinal axis extends and wherein the heat sink is located between the brushless DC motor and the combined PCB; and
a control PCB configured to receive motor positional information from the Hall sensor and control the power switching elements to drive the brushless DC motor;
wherein the second through-hole is larger than the first through-hole and the Hall sensor is located radially outward of the first through-hole and radially inward of the second through-hole.

18. The power tool of claim 17 , wherein the control PCB includes a processor and a memory.

19. The power tool of claim 17 , wherein the power switching elements are mounted on the combined PCB in a flat orientation.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Mergener Matthew J
• Kolden Michael
• Check William E
• Wycklendt Matthew P
• Beyerl Andrew T
• Thiele John W
• Hunkins Todd C

Classifications

• B25B21/02

  with means for imparting impact to screwdriver blade or nut socket · CPC title

• H05K7/20136

  Forced ventilation, e.g. by fans (H05K7/202 takes precedence) · CPC title

• H05K1/18

  structurally associated with non-printed electric components (H05K1/16 takes precedence) · CPC title

• H05K2201/10151

  Sensor · CPC title

• H05K7/20436

  Inner thermal coupling elements in heat dissipating housings, e.g. protrusions or depressions integrally formed in the housing · CPC title