Electronic module having a fuse in a power tool

Abstract

An electronic module for a power tool having an electric motor is provided including a printed circuit board (PCB), an inverter bridge circuit, a first conductive track disposed on the PCB and coupled to the power source, a second conductive track disposed on the PCB and coupled to the inverter bridge circuit, and a fuse strap provided between the first conductive track and the second conductive track. The fuse strap includes a main body spaced apart from the PCB, a first mounting portion mounted on the first conductive track via a first solder joint, and a second mounting portion mounted on the second conductive track via a second solder joint.

1 . An electronic module for a power tool having an electric motor, comprising:
 a printed circuit board (PCB);   an inverter bridge circuit including a plurality of power switches mounted on the PCB and configured to switchably supply electric power from a power source to the electric motor;   a first conductive track disposed on the PCB and coupled to the power source;   a second conductive track disposed on the PCB and coupled to the inverter bridge circuit;   at least one fuse electrically coupled between the first conductive track and the second conductive track, the at least one fuse having a first node secured to the first conductive track via a first solder joint and a second node secured to the second conductive track via a second solder joint; and   a metal slug thermally coupled to the first conductive track to absorb heat from the first solder joint.   
     
     
         2 . The electronic module of  claim 1 , wherein the metal slug is mounted on the first conductive track adjacent the first solder joint. 
     
     
         3 . The electronic module of  claim 1 , wherein the at least one fuse comprises two fuses electronically provided in parallel for a combined current rating of at least 60 Amps. 
     
     
         4 . The electronic module of  claim 1 , wherein a surface area of the metal slug is at least twice as large as a surface area of each of the at least one fuse. 
     
     
         5 . The electronic module of  claim 1 , further comprising a secondary slug mounted on the second conductive track adjacent the second solder joint. 
     
     
         6 . The electronic module of  claim 5 , wherein the metal slug has a greater surface area than the second slug. 
     
     
         7 . The electronic module of  claim 1 , wherein the motor is a brushless DC motor configured to output at least 1500 watts of power and the power source is a removable power tool battery pack. 
     
     
         8 . An electronic module for a power tool having an electric motor, comprising:
 a printed circuit board (PCB);   an inverter bridge circuit including a plurality of power switches mounted on the PCB and configured to switchably supply electric power from a power source to the electric motor;   a first conductive track disposed on the PCB and coupled to the power source;   a second conductive track disposed on the PCB and coupled to the inverter bridge circuit;   a first metal slug mounted on the first conductive track;   a second metal slug mounted on the second conductive track; and   at least one fuse including a first node mounted on the first metal slug and a second node mounted on the second metal slug such that the at least one fuse is spaced apart from the PCB.   
     
     
         9 . The electronic module of  claim 8 , comprising a first solder joint that secures the first node to the first metal slug and a second solder joint that secures the second node to the second metal slug. 
     
     
         10 . The electronic module of  claim 8 , further comprising an overmold structure disposed between at least one fuse and the PCB to secure the at least one fuse to the first metal slug and the second metal slug. 
     
     
         11 . The electronic module of  claim 8 , wherein the motor is a brushless DC motor configured to output at least 1500 watts of power and the power source is a removable power tool battery pack. 
     
     
         12 . A power tool comprising:
 a housing;   an electric motor disposed within the housing; and   an electronic module electrically coupled to the electric motor, comprising:
 a printed circuit board (PCB); 
 an inverter bridge circuit including a plurality of power switches mounted on the PCB and configured to switchably supply electric power from a power source to the electric motor; 
 a first conductive track disposed on the PCB and coupled to the power source; 
 a second conductive track disposed on the PCB and coupled to the inverter bridge circuit; 
 at least one fuse electrically coupled between the first conductive track and the second conductive track, the at least one fuse having a first node secured to the first conductive track via a first solder joint and a second node secured to the second conductive track via a second solder joint; and 
 a metal slug thermally coupled to the first conductive track to absorb heat from the first solder joint. 
   
     
     
         13 . The power tool of  claim 12 , wherein the metal slug is mounted on the first conductive track adjacent the first solder joint. 
     
     
         14 . The power tool of  claim 12 , wherein the at least one fuse comprises two fuses electronically provided in parallel for a combined current rating of at least 60 Amps. 
     
     
         15 . The power tool of  claim 12 , wherein a surface area of the metal slug is at least twice as large as a surface area of each of the at least one fuse. 
     
     
         16 . The power tool of  claim 12 , further comprising a secondary slug mounted on the second conductive track adjacent the second solder joint. 
     
     
         17 . The power tool of  claim 16 , wherein the metal slug has a greater surface area than the second slug. 
     
     
         18 . The power tool of  claim 12 , wherein the motor is a brushless DC motor configured to output at least 1500 watts of power and the power source is a removable power tool battery pack.