Printed circuit board assembly and power tool

Abstract

A printed circuit board assembly for use in a power tool includes a potting boat, a printed circuit board, a thermally conductive gap pad, a potting material, and an auxiliary heat sink. The potting boat includes main heat sink fins. An electronic component is mounted on a first surface of the printed circuit board. The gap pad contacts the electronic component and the pillar. The potting material at least partially encapsulates the printed circuit board within the potting boat. The auxiliary heat sink contacts a second surface of the printed circuit board opposite the first surface. The auxiliary radiator comprises auxiliary radiator fins. Heat generated by the electronic component is transferred via conduction to both the primary heat sink fin and the secondary heat sink fin. Heat is dissipated to the surroundings of the printed circuit board assembly.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 479,574, filed on January 12, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The utility model relates to a printed circuit board assembly, and more particularly to a printed circuit board assembly used in a power tool. Background Art

[0004] The power tool includes a motor configured to move a tool bit. The motor is operated by controlling the current supply of a power source. The flow of current to energize the motor can be controlled by one or more switches that are actuated during the energization of the motor. Actuating the switch generates heat. Some power tools include an impeller to dissipate the heat generated by the switch. Some power tools include a heat sink that is configured to conduct heat from the switch to heat sink fins for subsequent convection with the airflow generated by the impeller, thereby dissipating the heat generated by the switch to the surrounding environment of the power tool. Utility Model Content

[0005] On the one hand, the utility model provides a printed circuit board assembly for use in a power tool including a motor and a power supply. The printed circuit board assembly includes a potting boat, a printed circuit board, a thermally conductive gap pad, a potting material, and an auxiliary radiator. The potting boat includes an inner surface, at least one pillar extending away from the inner surface, and a plurality of main radiator fins. The printed circuit board includes a plurality of electronic components mounted on a first surface thereof, which are electrically connected to the motor and the power supply and are configured to transfer current from the power supply to the motor to enable the motor. The thermally conductive gap pad is positioned between the electronic components and the pillar and contacts the electronic components and the pillar. The potting material encapsulates the printed circuit board at least partially in the potting boat. The auxiliary radiator is at least partially positioned in the potting boat and contacts the second surface of the printed circuit board opposite to the first surface. The auxiliary radiator includes a plurality of auxiliary radiator fins protruding from the potting boat. The heat generated by the electronic components is transferred through a main conduction path passing through the gap pad, the pillar, and the main radiator fins. The heat generated by the electronic components is also transferred through an auxiliary conduction path passing through the auxiliary radiator and the auxiliary radiator fins. Heat generated by the electronic components is dissipated to the surrounding environment of the printed circuit board assembly along the primary conduction path and the secondary conduction path.

[0006] In some aspects, the printed circuit board includes a first hole, wherein the potting boat includes a fastener receiving boss, and wherein the printed circuit board assembly further includes a fastener securing the auxiliary heat sink and the printed circuit board to the potting boat.

[0007] In some aspects, the fastener receiving boss extends away from the interior surface.

[0008] In some aspects, the fastener secures both the printed circuit board and the auxiliary heat sink to the potting boat.

[0009] In some aspects, the thermally conductive gap pad at least partially deforms in response to the fastener securing the printed circuit board to the potting boat to reduce a gap between the electronic component and the standoff.

[0010] In some aspects, the auxiliary conductive path passes through the printed circuit board.

[0011] In some aspects, the potting boat includes an exterior surface having a non-finned section and a heat sink fin section from which at least one of the plurality of primary heat sink fins extends.

[0012] In some aspects, the heat sink fin section includes a first heat sink fin section and a second heat sink fin section, and the non-fin section is positioned between the first heat sink fin section and the second heat sink fin section.

[0013] In some aspects, the primary heat sink fins and the auxiliary heat sink fins are oriented substantially parallel to each other.

[0014] In some aspects, heat generated by the electronic components is dissipated both by a first airflow passing along the primary heat sink fins via a primary convection path and by a second airflow passing along the auxiliary heat sink fins via an auxiliary convection path.

[0015] In some aspects, at least one of the main heat sink fins extends only a partial width of the potting boat.

[0016] On the other hand, the utility model provides a power tool connected to a power source. The power tool includes a housing, a motor, an impeller and a printed circuit board assembly. The housing includes an inlet opening and a discharge opening. The impeller is rotated by the motor and is configured to generate an airflow in the housing, which is transferred from the inlet opening to the discharge opening. The printed circuit board assembly includes a potting boat, a printed circuit board, a thermally conductive gap pad, a potting material and an auxiliary radiator. The potting boat includes an inner surface, at least one pillar extending away from the inner surface, and a plurality of main radiator fins. The printed circuit board includes a plurality of electronic components mounted on its first surface. The plurality of electronic components are electrically connected to the motor and the power source and are configured to transfer current from the power source to the motor to enable the motor. The thermally conductive gap pad is positioned between the electronic components and the pillar and contacts both the electronic components and the pillar. The potting material encapsulates the printed circuit board at least partially in the potting boat. The auxiliary radiator is at least partially positioned in the potting boat and contacts the second surface of the printed circuit board opposite to the first surface. The auxiliary radiator includes a plurality of auxiliary radiator fins protruding from the potting boat. The heat generated by the electronic components is transferred through the primary conduction path through the gap pads, the protrusions, and the primary heat sink fins. The heat is also transferred through the secondary conduction path through the auxiliary heat sink and the secondary heat sink fins. The heat is dissipated along the primary conduction path, the secondary conduction path, and from the airflow via convection to the surrounding environment of the power tool.

[0017] In some aspects, the printed circuit board assembly is positioned upstream of the motor, and wherein the drain opening is positioned downstream of the motor.

[0018] In some aspects, the impeller is positioned downstream of the motor, between the motor and the discharge opening.

[0019] In some aspects, the motor is aligned along an axis that intersects the printed circuit board assembly.

[0020] In some aspects, the printed circuit board includes a first hole, wherein the potting boat includes a fastener receiving boss, and wherein the printed circuit board assembly further includes a fastener securing the auxiliary heat sink and the printed circuit board to the potting boat.

[0021] In some aspects, the auxiliary conductive path passes through the printed circuit board.

[0022] In some aspects, the potting boat further includes an exterior surface having a first heat sink fin section, a second heat sink fin section, and a non-fin section, and wherein at least one of the main heat sink fins extends from the exterior surface at the first heat sink fin section.

[0023] In some aspects, the airflow is divided into a first airflow path passing along these main heat sink fins and a second airflow path passing along these auxiliary heat sink fins, and wherein heat generated by these electronic components is dissipated via convection by the first airflow path along the main convection path and by the second airflow path along the auxiliary convection path.

[0024] On the other hand, the utility model provides a printed circuit board assembly for use in a power tool including a motor and a power supply. The printed circuit board assembly includes a potting boat, a printed circuit board, a thermally conductive gap pad, a potting material, and an auxiliary heat sink. The potting boat includes: an inner surface, at least one pillar extending from the inner surface; and an outer surface, the outer surface having a finless section, a full-length radiator fin section, and a partial-length radiator fin section, at least one full-length main radiator fin extending from the full-length radiator fin section, and at least one partial-length main radiator fin extending from the partial-length radiator fin section. The printed circuit board includes a plurality of electronic components mounted on a first surface thereof, which are electrically connected to the motor and the power supply and are configured to transfer current from the power supply to the motor to enable the motor. The thermally conductive gap pad is positioned between the electronic components and the pillar and contacts the electronic components and the pillar. The potting material encapsulates the printed circuit board at least partially in the potting boat. The auxiliary heat sink is at least partially positioned in the potting boat and contacts a second surface of the printed circuit board opposite to the first surface. The auxiliary heat sink includes a plurality of auxiliary heat sink fins protruding from the potting boat. The heat generated by the electronic components is transferred through a primary conduction path through the gap pads, the pillars, and both the main heat sink fins and the partial length main heat sink fins. The heat generated by the electronic components is also transferred through an auxiliary conduction path through the auxiliary heat sink and the auxiliary heat sink fins. The heat generated by the electronic components is dissipated to the surrounding environment of the printed circuit board assembly along the primary conduction path and the auxiliary conduction path.

[0025] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a cross-sectional view of a rotary hammer.

[0027] Figure 2 yes Figure 1 A perspective view of the printed circuit board assembly of the rotary hammer.

[0028] Figure 3 yes Figure 2 The printed circuit board assembly along Figure 2 A cross-sectional view taken along section line 3-3.

[0029] Figure 4 yes Figure 2The printed circuit board assembly along Figure 2 A cross-sectional view taken along section line 4-4.

[0030] Figure 5 yes Figure 1 A perspective view of an alternative printed circuit board assembly for a rotary hammer.

[0031] Figure 6 yes Figure 5 Another perspective view of an alternative printed circuit board assembly.

[0032] Figure 7 yes Figure 5 The printed circuit board assembly along Figure 5 A cross-sectional view taken along section line 7-7.

[0033] Before explaining any embodiment of the utility model in detail, it should be understood that the application of the utility model is not limited to the details of the construction and arrangement of components set forth in the following description or shown in the following drawings. The utility model can have other embodiments and can be practiced or implemented in many different ways. DETAILED DESCRIPTION

[0034] Figure 1 A reciprocating impact power tool, such as a rotary hammer 10, according to an embodiment of the present invention is shown. The rotary hammer 10 includes a housing 14, a motor 18 disposed within the housing 14, and a rotatable spindle 22 coupled to the motor 18 for receiving torque from the motor 18. In the illustrated embodiment, the rotary hammer 10 includes a quick release mechanism 24 that is coupled to rotate with the spindle 22 to facilitate quick removal and replacement of a tool bit 25. The tool bit 25 includes a recess 25a in which a stop member 26 of the quick release mechanism 24 is received to constrain axial movement of the tool bit 25 to the length of the recess 25a. The rotary hammer 10 defines a tool bit axis 27, which, in the illustrated embodiment, is coaxial with the rotation axis 28 of the spindle 22.

[0035] In the illustrated embodiment, the motor 18 is configured as a brushless direct current (BLDC) motor that receives power from an onboard power source 29 (e.g., a battery). The battery may include any of a number of different nominal voltages (e.g., 12V, 18V, etc.) and may be configured to have any of a number of different chemistries (e.g., lithium ion, nickel cadmium, etc.). In some embodiments, the battery is a battery pack that is removably coupled to the housing 14. In other embodiments, the motor 18 may be powered by a remote power source (e.g., a household electrical outlet) via a power cord (not shown). The motor 18 is selectively actuated by pressing an actuating member (e.g., a trigger 30), which in turn actuates an electrical switch 33. The switch 33 is electrically connected to the motor 18 via a printed circuit board assembly (PCBA) 200 (i.e., an electronic control unit 200). For example, the PCBA 200 may include a microprocessor and / or one or more circuits for controlling the operation of the motor 18.

[0036] The rotary hammer 10 further includes an impact mechanism 32 that can be switched between a plurality of operating modes by moving a mode selection dial 130 between a plurality of different positions. The mode selection dial 130 is configured to operate a mode selection assembly 300 to adjust the operation of the impact mechanism 32. Depending on the position of the mode selection dial 130, the impact mechanism 32 is configured to move the tool bit 25 axially and / or rotationally. In some examples, when operating the rotary hammer 10, the trigger 30 can be pressed and released to selectively enable the motor 18 at a plurality of different speeds. In other examples, the trigger 30 can be held in a pressed position to continuously operate the rotary hammer 10. In some embodiments, the rotary hammer 10 can include one or more control signal-based electrical overrides that involve driving the motor 18 in a direction opposite to the specified direction. There can be a variety of different arrangements for operating the rotary hammer 10.

[0037] Figures 1 to 5 A printed circuit board assembly (PCBA) 200 is shown that is configured to control the operation of the motor 18. Figure 1As shown, in the illustrated embodiment, the rotational axis 90 passes through the PCBA 200, wherein the PCBA 200 is positioned on an opposite side of the motor 18 than the mode selection dial 130. In the illustrated embodiment, the PCBA 200 is positioned adjacent to the bottom of the housing 14, and the mode selection dial 130 is positioned adjacent to the top of the housing 14. However, the PCBA 200 can be in other locations. For example, in the illustrated embodiment, the PCBA 200 is oriented substantially perpendicular to the rotational axis 90. However, in other embodiments, the PCBA 200 can be oriented at any angle (e.g., 15 degrees, 30 degrees, 45 degrees, 60 degrees, 105 degrees, 120 degrees, 135 degrees, 150 degrees, 175 degrees, etc.) relative to the rotational axis 90, which is inclined in any direction with respect to the rotational axis 90.

[0038] like Figure 1 As shown, the motor housing 14 has at least one side surface (eg, a side surface viewed from above) of the motor housing 14. Figure 1 The closest left side and the observer's observation Figure 1 The motor housing 14 includes one or more discharge openings 15 (schematically shown by dashed lines) on the right side (farthest away when in the mode selection dial 130). The discharge openings 15 are positioned between the motor 18 and the mode selection dial 130 so that fluid is discharged laterally from the motor housing 14. In other embodiments, the discharge openings 15 can be positioned downstream of the motor 18 in other ways. The motor housing 14 further includes a plurality of inlet openings 16, which are positioned at the bottom of the housing 14, wherein air enters the motor housing 14 in a direction parallel to the rotational axis 90. In this arrangement, the PCBA 200 is positioned upstream of the motor 18, between the motor 18 and the inlet openings 16. In other embodiments, the inlet openings 16 can be positioned upstream of the motor 18 in other ways, and optionally upstream of both the motor 18 and the PCBA 200. For example, the inlet openings 16 can be positioned adjacent to the bottom of the housing 14, but introduce and / or remove air in a lateral direction perpendicular to the direction of the rotational axis 90 as in Figure 1 Observed page.

[0039] Continue to refer Figure 1 , the motor 18 is coupled to an impeller 19 that generates an airflow AF through the housing 14 in response to rotation of the motor 18 and the impeller 19. In the illustrated embodiment, the impeller 19 is positioned downstream of the motor 18, between the motor 18 and the discharge opening 15. During operation of the rotary hammer 10, the motor 18 and the PCBA 200 generate heat. The airflow AF is directed through the inlet opening 16, around the PCBA 200, and then through and / or around the motor 18, thereby transferring heat from the PCBA 200 and the motor 18 to the airflow AF. The heated airflow AF is then discharged from the housing 14 via the discharge opening 15.

[0040] Figures 2 to 4 The PCBA 200 is shown in detail. The PCBA 200 includes a potting boat 204 including a plurality of primary fins 208 extending away from an exterior surface 209 of the potting boat 204. The potting boat 204 further includes a plurality of struts 212 extending away from an interior surface 210 in a direction opposite to the primary fins 208. In the illustrated embodiment, the primary fins 208 extend along the entire length of the potting boat 204 and include a thickness and spacing between the primary fins in the width dimension of the potting boat 204. In the illustrated embodiment, the primary fins 208 surround the sidewalls 206 of the potting boat 204. In other embodiments, the primary fins 208 may extend a portion of the length of the potting boat 204 and / or the sidewalls 206.

[0041] The PCBA 200 also includes a printed circuit board (PCB) 216 within the potting boat 204. Electronic components (e.g., a microprocessor, a field effect transistor or FET 220, etc.) are mounted on the PCB 216. The illustrated PCBA 200 includes a plurality of (e.g., six) FETs 220 mounted on the PCB 216 and configured to control the current supplied from the battery pack 29 to the motor 18. During operation of the motor 18, the FETs 220 are turned on and off in rapid succession, which generates heat. In some exemplary embodiments, the FETs 220 can be mounted to the PCB 216 in an H-bridge motor drive circuit. The FETs 220 are mounted on the PCB 216 at positions corresponding to the pillars 212.

[0042] A gap pad 224 having high thermal conductivity is positioned between the FET 220 and the pillar 212. In some embodiments, a single gap pad 224 may be positioned between each FET 220 and the pillar 212. In other embodiments, a plurality of gap pads 224 are provided, wherein each gap pad 224 is positioned between a corresponding one of the FETs 220 and a corresponding one of the pillars 212. The heat generated by the FET 220 is transferred through the gap pad 224 and enters the potting boat 204 (via the pillar 212). The potting boat 204 and the main fin 208 are also made of a thermally conductive material (e.g., aluminum), so that the heat generated by the FET 220 can be conducted to the main fin 208 through the potting boat 204 (e.g., via a first conduction path). As the airflow AF passes through the PCBA 200, heat is transferred from the main fins 208 to the airflow AF (more specifically, along the first airflow path AF1 of the main fins 208) via convection, and the heat is carried by the airflow AF through the discharge opening 16 and reaches the surrounding environment of the rotary hammer 10. Optionally, at least one side of the gap pad 224 may be applied with an adhesive. The adhesive may fix the gap pad 224 to the pillar 212 or one or more FETs 220, or both the pillar 212 and one or more FETs 220. The adhesive may be configured to improve the assembly efficiency of the PCBA 200 without affecting the thermal conductivity of the gap pad 224 and / or the PCBA 200 as a whole. In the illustrated embodiment, no adhesive is applied to the gap pad 224. In some embodiments, the gap pad 224 may be deformable (e.g., elastically deformable).

[0043] The PCBA 200 includes a potting material 228 ( Figure 3). The potting material 228 is positioned at least between the PCB 216 and the interior surface 210 of the potting boat 204. Optionally, the potting material 228 is also disposed on the opposite side of the PCB 216 that faces away from the interior surface 210. In the illustrated embodiment, the potting material 228 is disposed between the PCB 216 and the interior surface 210 of the potting boat 204, and on the opposite side of the PCB 216 that faces away from the interior surface 210. However, the potting material 228 is not positioned between the gap pad 224 and the pillar 212. The potting material 228 encapsulates at least some of the electronic devices (e.g., FET 220) mounted on the printed circuit board 216. The potting material 228 can inhibit damage to the electronic components. The potting material 228 is thermally conductive and electrically insulating. In this way, heat from the PCB 216 can be transferred to the potting boat 204 through the potting material 228. Due to the electrical insulation properties of the potting material 228, the current is inhibited from being transferred between the electronic components or multiple different electrical traces on the PCB 216 through the potting material 228. In some embodiments, the potting material 228 can be flame retardant. For example, the potting material 228 can be a polyurethane resin compound, such as RM2018 from Epic Resins of Palmyra, Wisconsin, USA. Since the potting material 228 is not positioned between the gap pad 224 and the pillar 212, heat can be directly transferred from the FET 220 to the potting boat 204 without being transferred through the potting material 228. In some embodiments, the thermal conductivity of the gap pad 224 can be higher than the thermal conductivity of the potting material 228. Accordingly, the heat generated by the FET 220 can be efficiently transferred to the potting boat 204 without passing through the potting material 228.

[0044] On the side of the PCB 216 opposite to the main fins 208, the PCBA 200 further includes an auxiliary heat sink 232. The auxiliary heat sink 232 includes auxiliary fins 236 and mounting holes 240 ( Figure 4 ). The auxiliary heat sink 232 and the auxiliary fins 236 are made of a thermally conductive material (e.g., aluminum). The auxiliary fins 236 of the auxiliary heat sink 232 extend away from both the interior surface 210 of the potting boat 204 and the PCB 216. The auxiliary fins 236 of the auxiliary heat sink 232 extend beyond the boundaries of the potting boat 204 so that these auxiliary fins are exposed to the airflow AF within the housing 14. Figure 4As shown, the mounting holes 240 receive fasteners 244 that secure the auxiliary heat sink 232 to the printed circuit board 216 and the potting boat 204. The potting boat 204 includes a fastening boss 248 having a threaded hole 252. The fastening boss 248 extends from the interior surface 210 in the same direction as the pillar 212. However, the fastening boss 248 extends further from the interior surface 210 than the pillar 212. The PCB 216 also has a fastening hole 256. The mounting hole 240 and the fastening holes 252, 256 are aligned with each other, and the fastener 244 passes through the mounting hole 240 and the fastening hole 256 to engage the threaded hole 252 in the fastening boss 248.

[0045] During assembly of PCBA 200, PCB 216 is positioned within potting boat 204, with fastening holes 252, 256 of PCB 216 and potting boat 204 aligned with each other. Gap pad 224 is positioned between pillar 212 and FET 220, optionally using the aforementioned adhesive. Auxiliary heat sink 232 is positioned on PCB 216, opposite potting boat 204, with mounting hole 240 aligned with fastening holes 252, 256. Fastener 244 is at least partially positioned within mounting hole 240 and fastening holes 252, 256, and fastener 244 is tightened. During tightening, a clamping force is applied to PCB 216, and gap pad 224 is pressed against pillar 212. During tightening of fastener 244, gap pad 224 is deformed (i.e., deflected) to reduce or occupy gap G1 ( Figure 4 ). The gap pad 224 is at least partially deformed in response to the fastener 244 securing the PCB 216 to the potting boat 204 to reduce the gap G1 between the pillars 212. When the fastener 244 is fully tightened, the gap pad 224 contacts both the FET 220 and the pillar 212. The clamping force generated by the fastener 244 deforms the gap pad 224 and holds the gap pad 224 on the pillar 212. After the fastener 244 is tightened, the potting material 228 is applied to the printed circuit board 216 through the injection hole 260 ( Figure 2 ). The injection hole 260 is a through hole configured to allow the potting material 228 to reach a position between the interior surface 210 and the PCB 216 from the surrounding environment of the PCBA 200 on one side of the PCB 216. After the interior of the PCBA 200, the PCB 216 and the interior surface 210 are filled with the potting material 228, the potting material 228 can continue to be applied to fill the potting boat 204 on the opposite side of the PCB 216 facing away from the interior surface 210.

[0046] The stacked arrangement of the FET 220, the printed circuit board 216, and the auxiliary heat sink 232 allows heat generated by the FET 220 to be conducted (e.g., via a second conduction path) through the printed circuit board 216, into the auxiliary heat sink 232, and to the auxiliary fins 236 of the auxiliary heat sink 232. During operation of the rotary hammer 10, the motor 18 rotates to drive the impeller 19 and draws an airflow AF into the motor housing 14 via the inlet opening 16. The airflow AF is guided through the PCBA 200 and the motor 18, and then discharged from the exhaust opening 15. As the airflow AF passes through the PCBA 200, heat is transferred from the auxiliary fins 236 of the auxiliary heat sink 232 to the airflow AF (more specifically, along the second airflow path AF2 passing through the auxiliary fins 236) via convection, and the heat is carried by the airflow AF through the exhaust opening 15 and to the surrounding environment of the rotary hammer 10. Depending on the orientation of the PCBA 200, the airflow AF generated by the impeller 19 may be divided into a first airflow path AF1 passing along the main fins 208 and a second airflow path AF2 passing along the auxiliary fins 236. After passing through the PCBA 200, the first airflow path AF1 and the second airflow path AF2 may converge with each other to be discharged through the discharge opening 15. Depending at least on the orientation of the PCBA 200, the order in which the airflow AF passes along the main fins 208 and the auxiliary fins 236 may be different. For example, the airflow AF may first contact the main fins 208 or the auxiliary fins 236. Alternatively, the airflow AF may contact both the main fins 208 and the auxiliary fins 236 at the same time. Figure 1 As shown, with the PCBA 200 shown oriented perpendicular to the axis of rotation 90, the first airflow path AF1 passes along the main fins 208, and then the second airflow path AF2 passes along the auxiliary fins 236. In the illustrated embodiment, the main fins 208 and the auxiliary fins 236 are oriented substantially parallel to each other. Despite possible manufacturing tolerances and other differences, this parallel arrangement of the main fins 208 and the auxiliary fins 236 promotes airflow along the PCBA 200 for convective heat transfer while being substantially unimpeded by the main fins 208 and the auxiliary fins 236 themselves.

[0047] Figures 5 to 7 An alternative printed circuit board assembly (PCBA) 300 is shown. The PCBA 300 includes a potting boat 304 that includes an exterior surface 304a. The exterior surface 304a includes at least one full-length fin segment 304b and at least one partial-length fin segment 304d. The potting boat 304 further includes at least one finless segment 304c. The potting boat 304 further includes an interior surface 304e opposite the exterior surface 304a.

[0048] The potting boat 304 includes a plurality of main fins 308 extending away from the external surface 304a. More specifically, the main fins 308 extend away from the external surface 304a at the full-length radiator fin section 304b and the partial-length fin section 304d. At the full-length fin section 304b, at least one full-length main radiator fin 308 extends from the external surface 304a. The full-length main radiator fins 308 extend along the entire width dimension D1 of the potting boat 304 and include thickness and spacing between the full-length main radiator fins on the length dimension D2 of the potting boat 304. In the illustrated embodiment, the full-length main radiator fins 308 surround the sidewall 306 of the potting boat 304.

[0049] At the displayed partial length fin section 304d, at least one partial length main radiator fin 308a extends from the external surface 304a. The partial length main radiator fin 308a extends a partial width (along the width dimension D1) of the potting boat 304 and / or the sidewall 306. The displayed finless section 304c is located between adjacent partial length main radiator fins 308a. Along the length dimension D2, the displayed potting boat 304 includes a plurality of full length fin sections 304b and a plurality of partial length fin sections 304d and a plurality of full length fin sections and a plurality of partial length fin sections alternate with each other. At a given length dimension D2 corresponding to the partial length fin section 304d, the finless section 304c separates the partial length fins 308a from each other. In other embodiments, along the length dimension D2, the radiator fin sections 308b, 304b can be separated from each other by the finless section 304c.

[0050] refer to Figure 5 and Figure 7 , the potting boat 304 includes a plurality of FET pillars 312, heat sink fastening pillars 313, and PCB fastening pillars 314 extending from the interior surface 304e. In the illustrated embodiment, the FET pillars 312, heat sink fastening pillars 313, and PCB fastening pillars 314 extend from the interior surface 304e by different distances. Figure 7 As shown, when the PCB 316 is mounted in the potting boat 304, gaps D3, D4, and D5 of different lengths exist between the first surface 316a of the PCB 316 and the inner surface 304e (gap D3), between the first surface 316a of the PCB 316 and the FET pillars 312 (gap D4), and between the first surface 316a of the PCB 316 and the PCB fastening pillars 314 (gap D5). In some embodiments, the PCB 316 may contact the PCB fastening pillars 314 so that the gap D5 is nominally zero.

[0051] refer to Figure 6 and Figure 7, the potting boat 304 includes a plurality of heat sink fastener receiving seats 320, FET cavities 324 and PCB fastening holes 328. The heat sink fastener receiving seats 320 are opposite to, or in other words aligned with, the heat sink fastening pillars 323. The heat sink fastener receiving seats 320 are sized to receive fasteners (not shown) that can secure the PCBA 300 to the rotary hammer 10 or any other device. The FET cavities 324 are opposite to, or in other words aligned with, the FET pillars 312. The FET cavities 324 are recessed into the outer surface 304a of the potting boat 304. The PCB fastening holes 328 are opposite to, or in other words aligned with, the PCB fastening pillars 314. In the illustrated embodiment, the PCB fastening holes 328 are sized to receive fasteners 329 that secure the PCB 316 to the potting boat 304. As shown Figure 7 As shown, the PCB fastening holes 328 are through holes that extend from the exterior surface 304a through the entire PCB fastening pillar 314 so that the fastening holes 328 can be accessed from the interior surface 304e. In the illustrated embodiment, the non-finned section 304c of the exterior surface 304a is located between the adjacent FET cavity 324 and the PCB fastening hole 328.

[0052] The PCBA 300 also includes a printed circuit board (PCB) 316 (such as PCB 216) in the potting boat 304 and will not be described in detail. The printed circuit board 316 further includes a second surface 316b opposite to the first surface 316a, and the second surface 316b can contact an auxiliary heat sink (such as auxiliary heat sink 232) to dissipate the heat generated by the FET 332 of the PCBA 300.

[0053] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention described.

[0054] Various features of the invention are set forth in the appended claims.

Claims

1. A printed circuit board assembly for use in a power tool comprising a motor and a power source, characterized in that: The printed circuit board assembly comprises: a potting boat comprising an interior surface, at least one strut extending away from the interior surface, and a plurality of main heat sink fins; a printed circuit board including a plurality of electronic components mounted on a first surface thereof, the electronic components being in electrical communication with the motor and the power source and configured to pass current from the power source to the motor to enable the motor; a thermally conductive gap pad positioned between the electronic component and the support post and in contact with both the electronic component and the support post; a potting material that at least partially encapsulates the printed circuit board within the potting boat; and an auxiliary heat sink at least partially positioned within the potting boat in contact with a second surface of the printed circuit board opposite the first surface, the auxiliary heat sink comprising a plurality of auxiliary heat sink fins protruding from the potting boat, wherein heat generated by the electronic components is transferred via a primary conduction path through the gap pad, the support and the primary heat sink fins, wherein the heat generated by the electronic components is also transferred via an auxiliary conduction path through the auxiliary heat sink and the auxiliary heat sink fins, and The heat generated by the electronic components is dissipated to the surrounding environment of the printed circuit board assembly along the main conduction path and the auxiliary conduction path.

2. The printed circuit board assembly according to claim 1, wherein: The printed circuit board includes a first hole, wherein the potting boat includes a fastener receiving boss, and wherein the printed circuit board assembly further includes a fastener securing the auxiliary heat sink and the printed circuit board to the potting boat.

3. The printed circuit board assembly according to claim 2, wherein: The fastener receiving boss extends away from the interior surface.

4. The printed circuit board assembly according to claim 2, wherein: The fastener secures both the printed circuit board and the auxiliary heat sink to the potting boat.

5. The printed circuit board assembly according to claim 4, wherein: The thermally conductive gap pad at least partially deforms in response to the fastener securing the printed circuit board to the potting boat to reduce a gap between the electronic component and the standoff.

6. The printed circuit board assembly according to claim 1, wherein: The auxiliary conducting path passes through the printed circuit board.

7. The printed circuit board assembly according to claim 1, wherein: The potting boat includes an exterior surface having a non-finned section and a heat sink fin section from which at least one of the plurality of main heat sink fins extends.

8. The printed circuit board assembly according to claim 7, wherein: The heat sink fin section includes a first heat sink fin section and a second heat sink fin section, and the finless section is positioned between the first heat sink fin section and the second heat sink fin section.

9. The printed circuit board assembly according to claim 1, wherein: The main radiator fins and the auxiliary radiator fins are oriented generally parallel to each other.

10. The printed circuit board assembly according to claim 1, wherein: Heat generated by the electronic components is dissipated both by a first airflow passing along the primary heat sink fins via a primary convection path and by a second airflow passing along the auxiliary heat sink fins via an auxiliary convection path.

11. The printed circuit board assembly according to claim 1, wherein: At least one of the main heat sink fins extends only a partial width of the potting boat.

12. A power tool connected to a power source, characterized in that: The power tool includes: a housing including an inlet opening and a discharge opening; motor; an impeller rotated by the motor and configured to generate an airflow within the housing that passes from the inlet opening to the discharge opening; and A printed circuit board assembly, the printed circuit board assembly comprising: a potting boat comprising an interior surface, at least one support leg extending away from the interior surface, and a plurality of main heat sink fins, a printed circuit board including a plurality of electronic components mounted on a first surface thereof, the plurality of electronic components being in electrical communication with the motor and the power source and configured to pass current from the power source to the motor to enable the motor, a thermally conductive gap pad positioned between the electronic component and the support post and in contact with both the electronic component and the support post, a potting material that at least partially encapsulates the printed circuit board within the potting boat, and an auxiliary heat sink at least partially positioned within the potting boat in contact with a second surface of the printed circuit board opposite the first surface, the auxiliary heat sink comprising a plurality of auxiliary heat sink fins protruding from the potting boat; wherein heat generated by the electronic components is transferred via a primary conduction path through the gap pad, the protrusions, and the primary heat sink fins, wherein the heat generated by the electronic components is also transferred via an auxiliary conduction path through the auxiliary heat sink and the auxiliary heat sink fins, and Therein, heat generated by the electronic components is dissipated along the primary conduction path, the secondary conduction path and from the airflow via convection to the surrounding environment of the power tool.

13. The power tool according to claim 12, characterized in that: The printed circuit board assembly is positioned upstream of the motor, and wherein the drain opening is positioned downstream of the motor.

14. The power tool according to claim 12, characterized in that: The impeller is positioned downstream of the motor, between the motor and the discharge opening.

15. The power tool according to claim 12, characterized in that: The motor is aligned along an axis that intersects the printed circuit board assembly.

16. The power tool according to claim 15, characterized in that: The printed circuit board includes a first hole, wherein the potting boat includes a fastener receiving boss, and wherein the printed circuit board assembly further includes a fastener securing the auxiliary heat sink and the printed circuit board to the potting boat.

17. The power tool according to claim 12, characterized in that: The auxiliary conducting path passes through the printed circuit board.

18. The power tool according to claim 12, characterized in that: The potting boat further includes an exterior surface having a first heat sink fin section, a second heat sink fin section, and a non-fin section, and wherein at least one of the main heat sink fins extends from the exterior surface at the first heat sink fin section.

19. The power tool according to claim 12, characterized in that: The airflow is divided into a first airflow path passing along these main heat sink fins and a second airflow path passing along these auxiliary heat sink fins, and wherein heat generated by these electronic components is dissipated by the first airflow path along the main convection path and by the second airflow path along the auxiliary convection path via convection.

20. A printed circuit board assembly for use in a power tool comprising a motor and a power source, characterized in that: The printed circuit board assembly comprises: A potting boat comprising: an interior surface from which at least one strut extends; and an exterior surface having a non-finned section, a full-length radiator fin section, and a partial-length radiator fin section, at least one full-length main radiator fin extending from the full-length radiator fin section, at least one partial-length main radiator fin extending from the partial-length radiator fin section, and a printed circuit board including a plurality of electronic components mounted on a first surface thereof, the electronic components being in electrical communication with the motor and the power source and configured to pass current from the power source to the motor to enable the motor; a thermally conductive gap pad positioned between the electronic component and the support post and in contact with both the electronic component and the support post; a potting material that at least partially encapsulates the printed circuit board within the potting boat; and an auxiliary heat sink at least partially positioned within the potting boat in contact with a second surface of the printed circuit board opposite the first surface, the auxiliary heat sink comprising a plurality of auxiliary heat sink fins protruding from the potting boat, wherein heat generated by the electronic components is transferred via a primary conduction path through the gap pad, the support, and both the full-length main heat sink fins and the partial-length main heat sink fins, wherein the heat generated by the electronic components is also transferred via an auxiliary conduction path through the auxiliary heat sink and the auxiliary heat sink fins, and The heat generated by the electronic components is dissipated to the surrounding environment of the printed circuit board assembly along the main conduction path and the auxiliary conduction path.

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