Power tool with busbar

Abstract

A power tool can include a housing. The power tool can include an electric motor. The power tool can include a printed circuit board assembly configured to supply current to the electric motor. The power tool can include an output unit operably coupled to the electric motor. The power tool can include a tool terminal block supported by the housing and including a tool terminal configured to electrically couple to a battery pack. The power tool can include a busbar extending between the tool terminal and the printed circuit board assembly and electrically connecting the tool terminal to the printed circuit board assembly, wherein a portion of the busbar defines the tool terminal.

Description

[0001] Cross-reference to related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 728,374, filed December 5, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to power tools, and more particularly to battery-powered portable power tools. Background Technology

[0003] Power tools, especially those operating at high power levels, rely on efficient electrical connections to ensure optimal performance. Traditional interconnections, such as the B+ and B- lines and phase lines to the motor, are typically made of conductive metal wires of various gauges, usually surrounded by an insulating sheath. These wires have limitations related to contact resistance at solder joints, heat dissipation due to insulation on the wires, and assembly complexity due to the soldering required during assembly. Summary of the Invention

[0004] In some aspects, the technology described in this invention relates to a power tool configured to be selectively and removably coupled to a battery pack, the power tool comprising: a housing; an electric motor; a printed circuit board assembly configured to supply current to the electric motor; an output unit operatively coupled to the electric motor; a tool terminal block supported by the housing and including tool terminals configured to be electrically coupled to the battery pack; and a busbar extending between the tool terminals and the printed circuit board assembly and electrically connecting the tool terminals to the printed circuit board assembly; wherein at least a portion of the busbar defines the tool terminals.

[0005] In some aspects, the technology described in this invention relates to power tools, wherein the housing comprises a resin material, and wherein the busbar is at least partially embedded within the resin material.

[0006] In some aspects, the technology described in this invention relates to power tools in which busbars and housing inserts are molded.

[0007] In some aspects, the technology described in this invention relates to power tools, wherein the busbar is rigid and comprises a plurality of straight sections connected by a plurality of non-linear portions.

[0008] In some aspects, the technology described in this invention relates to power tools, wherein a plurality of straight segments include a first segment, a second segment, a third segment, and a fourth segment that are not oriented parallel to each other and are connected at non-straight portions.

[0009] In some aspects, the technology described in this invention relates to power tools, wherein a busbar includes a first end and a second end, a tool terminal is located at the first end, and the second end defines an aperture configured to receive a screw for fastening the second end to a printed circuit board assembly.

[0010] In some aspects, the technology described in this invention relates to power tools, wherein a busbar is a first busbar and a tool terminal is a first tool terminal, and wherein the power tool further includes a second tool terminal and a second busbar extending between and electrically connecting the second tool terminal and the printed circuit board assembly.

[0011] In some aspects, the technology described in this invention relates to power tools, wherein the busbar comprises a single monolithic conductive member formed of a conductive metal selected from copper, zinc, aluminum, or alloys thereof.

[0012] In some aspects, the technology described in this invention relates to power tools, wherein at least a portion of the busbar is exposed within the housing to airflow generated by the power tool's fan for heat dissipation.

[0013] In some aspects, the technology described in this invention relates to power tools in which an exposed portion of a busbar is thermally coupled to a radiator disposed within a housing.

[0014] In some aspects, the technology described in this invention relates to power tools, wherein a busbar includes a first end and a second end, a tool terminal is located at the first end, and the second end is electrically attached to a printed circuit board assembly via solder connection.

[0015] In some aspects, the technology described in this invention relates to power tools, wherein the power tools further include a plurality of phase busbars that electrically connect printed circuit board assemblies to respective phase windings of an electric motor.

[0016] In some aspects, the technology described in this invention relates to power tools, wherein the end of each phase busbar is fixed to the stator insulator of an electric motor.

[0017] In some aspects, the technology described in this invention relates to power tools, wherein each phase busbar includes a single monolithic conductive member formed of conductive metal and molded to a housing.

[0018] In some aspects, the technology described in this invention relates to power tools, wherein the tool terminals are male terminals configured to be received by corresponding female terminals of a battery pack.

[0019] In some aspects, the technology described in this invention relates to a busbar for a battery-powered portable power tool, the busbar comprising: a single monolithic conductive member having: a first end defining a tool terminal configured to mate with a battery pack terminal, a second end configured to be electrically attached to a printed circuit board assembly, and a plurality of straight segments connected by a non-linear portion between the first end and the second end; wherein the busbar is rigid and formed of a conductive metal.

[0020] In some aspects, the technology described in this invention relates to a busbar, wherein a second end defines a mounting hole configured to receive threaded fasteners to couple the busbar to a printed circuit board assembly.

[0021] In some aspects, the technology described in this invention relates to busbars configured as inserts molded into the housing of a battery-powered portable power tool.

[0022] In some aspects, the technology described in this invention relates to a method of assembling a battery-powered portable power tool, the method comprising: molding a busbar insert into a housing of the battery-powered portable power tool, the busbar having a first end and a second end; and electrically attaching the second end of the busbar to a printed circuit board assembly of the battery-powered portable power tool; wherein the first end of the busbar defines a tool terminal configured to mate with battery pack terminals of a battery pack.

[0023] In some aspects, the technology described in this invention relates to a method that further includes inserting a screw through a hole in a second end of a busbar and fastening the second end to a printed circuit board assembly via the screw, wherein the busbar is rigid and formed of copper, zinc, aluminum, or an alloy thereof. Attached Figure Description

[0024] Figure 1 This is a side view of a conventional power tool, with a portion of the housing removed.

[0025] Figure 2 yes Figure 1 A partial perspective view of the terminal block of a prior art power tool.

[0026] Figure 3 It is a 3D diagram of the battery pack.

[0027] Figure 4 This is a side view of a power tool according to an embodiment of the present invention, wherein a portion of the housing has been removed.

[0028] Figure 5 yes Figure 4 A partial perspective view of the terminal block of a power tool.

[0029] Figure 6 yes Figure 4 A 3D view of the power busbar of a power tool.

[0030] Figure 7A It is attached to Figure 4 Printed circuit board assembly (PCBA) of power tools Figure 6 A partial 3D view of the power busbar.

[0031] Figure 7B It is attached to another embodiment of the present invention. Figure 4 Printed circuit board assembly (PCBA) of power tools Figure 6 A partial 3D view of the power busbar.

[0032] Figure 8 yes Figure 4 The housing of the power tool and Figure 6 A partial side view of the power busbar.

[0033] Figure 9 It is shown Figure 4 A schematic diagram of a power tool comprising a plurality of phase busbars. Detailed Implementation

[0034] Before explaining any independent embodiments of the invention in detail, it should be understood that the invention, in its application, is not limited to the details of the construction and arrangement of the components described in the following description or shown in the drawings. The invention can have other independent embodiments and can be practiced or implemented in various ways.

[0035] When used in this invention, the words “comprising” and “including” and variations thereof are intended to cover the items listed thereafter and their equivalents, as well as additional items. When used in this invention, the words “consisting of” and variations thereof are intended to cover only the items listed thereafter and their equivalents.

[0036] Relative terms used in conjunction with quantities or conditions, such as “about,” “approximately,” “generally,” etc., will be understood by one of ordinary skill in the art to include the stated value and have a meaning determined by the context (e.g., the term includes at least the degree of error associated with the measurement, the tolerance associated with a particular value (e.g., manufacturing, assembly, use, etc.)). Such terms should also be considered to disclose a range defined by the absolute values ​​of two endpoints. For example, the expression “about 2 to about 4” also discloses a range “2 to 4.” Relative terms may refer to a percentage added to or subtracted from the indicated value (e.g., 1%, 5%, 10% or more).

[0037] Furthermore, the functions described in this invention as performed by one component can be performed by multiple components in a distributed manner. Similarly, functions performed by multiple components can be combined and performed by a single component. Likewise, components described as performing specific functions can also perform additional functions not described in this invention. For example, a device or structure "configured" in a certain way is at least configured in that way, but may also be configured in ways not listed.

[0038] Figure 1 and Figure 2 This illustration shows all or part of a prior art power tool 10 (e.g., a cutting saw). The power tool 10 includes a housing 14, a battery socket 18, an electric motor 22, a printed circuit board assembly (PCBA) 26, and an output unit 30. The electric motor 22 is operatively coupled to the output unit 30 to provide torque to the output unit 30. The PCBA 26 provides current to the electric motor 22 to electronically commutate the electric motor 22. The battery socket 18 is selectively coupled to a removable battery pack 34. The battery socket 18 includes a tool terminal block 38 having a plurality of tool terminals 42 (e.g., male terminals, such as blade terminals). Figure 2 Battery pack 34 ( Figure 3 It includes a corresponding battery terminal block 46 having a plurality of battery terminals 50 (e.g., female terminals, such as spring clip terminals), which receive tool terminals 42 when the battery pack 34 is coupled to the power tool 10.

[0039] Figure 2 A tool terminal block 38 of a prior art power tool 10 is shown. Tool terminals 42 are connected to power conductors 54 (e.g., via soldering), which extend from tool terminals 42 to PCBA 26. Figure 1 Power conductor 54 electrically connects tool terminal 42 to PCBA 26 and allows current to flow from battery pack 34 to PCBA 26. The ends of power conductor 54 are typically attached to PCBA 26 and tool terminal 42 via solder joints.

[0040] Figure 4-8 A power tool 100 according to an embodiment of the present invention is shown. Similar to power tool 10, power tool 100 includes a housing 114, a battery socket 118, an electric motor 122, a printed circuit board assembly (PCBA) 126, and an output unit 130. The electric motor 122 is operatively coupled to the output unit 130 to provide torque to the output unit 130. The PCBA 126 provides current to the electric motor 122 to electronically commutate the electric motor 122. The battery socket 118 is selectively coupled to a removable battery pack 34. Figure 3 The battery socket 118 includes a tool terminal block 138 having a plurality of tool terminals 142 (e.g., male terminals, such as blade terminals). Figure 5When the battery pack 34 is coupled to the power tool 100, the battery terminal 50 of the battery pack 34 receives the tool terminal 142.

[0041] The power tool 100 does not include power leads connecting tool terminals 142 to PCBA 126. Instead, the power tool 100 includes busbars 154 electrically connecting PCBA 126 to battery pack 34. Busbars 154 are formed of a conductive metal (e.g., copper, zinc, aluminum, their alloys, or other metals). Unlike prior art power leads 54, each busbar 154 may include a single monolithic section and may be relatively rigid, i.e., non-flexible.

[0042] See Figure 4-6 In the illustrated embodiment, each busbar 154 includes a first end 158 and a second end 162 opposite to the first end. The first end 158 of each busbar 154 defines a tool terminal 142. Thus, the first end 158 does not require soldering or other electrical connection to a separate tool terminal assembly, resulting in lower impedance and resistance compared to the prior art. The second end 162 is configured for electrical connection to a PCBA 126. In the illustrated embodiment, the second end 162 defines a hole 166 (e.g., a mounting hole) that can receive a screw 170. Figure 7A (or other fasteners) to form a direct connection with PCBA 126. In other embodiments, hole 166 may be omitted, and busbar 154 may be connected via means such as soldering ( Figure 7B Other means such as clamping connection, welding connection, etc., are electrically attached to PCBA 126.

[0043] See Figure 6 Each busbar 154 includes a plurality of sections or straight segments 172, including a first segment 172a, a second segment 172b, a third segment 172c, and a fourth segment 172d. Each of the straight segments 172 is oriented to be non-parallel to each other and connects to each other at non-straight portions 176. Because the busbar 154 is rigid, it can be pre-formed (e.g., stamped, bent, etc.) into a non-straight shape including multiple non-parallel straight segments 172 to extend unimpeded through the housing 114 of the power tool 100.

[0044] See Figure 8All or part of the busbar 154 can be molded to the housing 114. For example, in some embodiments, the busbar 154 can be insert-molded with the housing 114. In such embodiments, the busbar 154 can be substantially embedded within the resin material forming the housing 114, or the busbar 154 can be partially embedded such that a portion of the busbar 154 remains substantially exposed. Inserting the busbar 154 into the housing 114 simplifies and accelerates the assembly process of the power tool 100. Furthermore, the exposed portion of the busbar 154 can improve the heat dissipation of the power tool 100 by keeping it exposed to the cooling airflow moving through the power tool 100 during operation (e.g., generated by a fan within the power tool 100). The exposed portion of the busbar 154 can also be selectively coupled to one or more heat sinks (not shown) within the housing 114 to further improve cooling.

[0045] See Figure 9 In some embodiments, the power tool 10 includes busbars 180, such as phase busbars, that electrically connect the PCBA 126 to the electric motor 22. Similar to busbar 154, busbars 180 are formed of a conductive metal (e.g., copper, zinc, aluminum, their alloys, or other metals). Each busbar 180 may include a single monolithic portion and may be relatively rigid, i.e., non-flexible. Busbars 180 may also be coupled to housing 114 by molding in a manner similar to that described in this invention with respect to busbar 154. One end of each busbar 180 may be attached to the PCBA 126 via threaded fasteners or by other means such as brazing, clamping, fusion welding, etc. The other end of each busbar 180 may be secured to the electric motor 22, for example, to a stator insulator (not shown), and may be connected to a corresponding phase (not shown) of the motor windings to provide current to each winding phase.

[0046] Although the invention has been described in detail in conjunction with certain preferred embodiments, variations and modifications are possible within the scope and spirit of one or more independent aspects of the invention described. Various features and / or advantages of the invention are set forth in the appended claims.

Claims

1. A power tool configured to be selectively and removably coupled to a battery pack, the power tool comprising: case; electric motor; A printed circuit board assembly configured to supply current to the electric motor; An output unit, the output unit being operatively coupled to the electric motor; A tool terminal block, the tool terminal block being supported by the housing and including tool terminals configured to be electrically coupled to the battery pack; and A busbar extending between the tool terminals and the printed circuit board and electrically connecting the tool terminals to the printed circuit board assembly; At least a portion of the busbar defines the tool terminal.

2. The power tool of claim 1, wherein the housing comprises a resin material, and wherein the busbar is at least partially embedded within the resin material.

3. The power tool as claimed in claim 2, wherein, The busbar is molded with the housing insert.

4. The power tool as claimed in claim 1, wherein, The busbar is rigid and comprises a plurality of straight sections connected by a plurality of non-straight portions.

5. The power tool as claimed in claim 4, wherein, The plurality of straight segments include a first segment, a second segment, a third segment, and a fourth segment, which are oriented to be non-parallel to each other and connected at the non-straight portions.

6. The power tool as claimed in claim 1, wherein, The busbar includes a first end and a second end, the tool terminal is located at the first end, and the second end defines a hole configured to receive a screw for fastening the second end to the printed circuit board assembly.

7. The power tool of claim 1, wherein the busbar is a first busbar and the tool terminal is a first tool terminal, and wherein the power tool further includes a second tool terminal and a second busbar, the second busbar extending between the second tool terminal and the printed circuit board assembly and electrically connecting the second tool terminal and the printed circuit board assembly.

8. The power tool of claim 1, wherein the busbar comprises a single monolithic conductive member formed of a conductive metal selected from copper, zinc, aluminum, or alloys thereof.

9. The power tool as claimed in claim 8, wherein, At least a portion of the busbar is exposed within the housing to airflow generated by the fan of the power tool for heat dissipation.

10. The power tool of claim 9, wherein the exposed portion of the busbar is thermally coupled to a radiator disposed within the housing.

11. The power tool of claim 1, wherein the busbar includes a first end and a second end, the tool terminal is located at the first end, and the second end is electrically attached to the printed circuit board assembly by solder connection.

12. The power tool as claimed in claim 1, wherein, The power tool further includes a plurality of phase busbars that electrically connect the printed circuit board assembly to the respective phase windings of the electric motor.

13. The power tool as claimed in claim 12, wherein, The end of each phase busbar is fixed to the stator insulator of the electric motor.

14. The power tool as claimed in claim 12, wherein, Each phase busbar includes a single monolithic conductive component formed of conductive metal and molded to the housing.

15. The power tool as claimed in claim 1, wherein, The tool terminal is a male terminal, and the male terminal is configured to be received by the corresponding female terminal of the battery pack.

16. A busbar for a battery-powered portable power tool, the busbar comprising: A single monolithic conductive component, wherein the single monolithic conductive component has: A first end defines a tool terminal configured to mate with a battery pack terminal. The second terminal is configured to be electrically attached to a printed circuit board assembly, and A plurality of straight segments, wherein the plurality of straight segments are connected by a non-straight portion between the first end and the second end; The busbars thereon are rigid and formed of conductive metal.

17. The busbar as described in claim 16, wherein, The second end defines a mounting hole configured to receive a threaded fastener to couple the busbar to the printed circuit board assembly.

18. The busbar as described in claim 16, wherein, The busbar is configured as an insert molded into the housing of the battery-powered portable power tool.

19. A method for assembling a battery-powered portable power tool, the method comprising: A busbar insert is molded into the housing of the battery-powered portable power tool, the busbar having a first end and a second end; and The second terminal of the busbar is electrically attached to the printed circuit board assembly of the battery-powered portable power tool; The first end of the busbar defines a tool terminal, which is configured to mate with the battery pack terminal of the battery pack.

20. The method of claim 19, further comprising inserting a screw through a hole in the second end of the busbar and securing the second end to the printed circuit board assembly via the screw, wherein the busbar is rigid and formed of copper, zinc, aluminum, or an alloy thereof.

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