Power Tools

Abstract

A power tool (1) is disclosed, comprising: an electric motor (3) configured to provide power to a tool (5) of the power tool (1); a power supply device (7, 9) configured to supply power to the electric motor (3); and an air cooling path (11, 11') extending through at least a portion of the electric motor (3) and at least a portion of the power supply device (7, 9) so as to cool the electric motor (3) and the power supply device (7, 9) when air flows through the air cooling path (11, 11'). The power tool (1) further comprises a fan (13) arranged in the air cooling path (11, 11') between the electric motor (3) and the power supply device (7, 9). The fan (13) is configured to generate an air flow passing through the air cooling path (11, 11') in a flow direction (d) from the electric motor (3) toward the power supply device (7, 9).

Description

Technical Field

[0001] The present disclosure relates to power tools, and more particularly to an electrically driven handheld power tool. Background Art

[0002] There are many kinds of power tools on the market today, such as chain saws, circular saws, trimmers, hedge trimmers, lawn mowers, multi-purpose tools, drills, etc. These power tools are used in industries, construction, gardens, housework, and around the house to achieve purposes such as driving fasteners, drilling, cutting, shaping, sanding, grinding, routing, polishing, painting, heating, etc.

[0003] A common feature of power tools is that they include tools that can be driven by a power source rather than just by manual labor. Currently, many power tools include an electric motor configured to provide power to the tool. Electric motors have some advantages over internal combustion engines, particularly in terms of emission levels, efficiency, noise levels, weight, etc. Some electrically driven power tools include batteries, and some power tools include electrical connections for connecting the power tool to a power source. In order to meet the needs of consumers and professional users, many power tools are equipped with high-power electric motors, which require high-power power supply devices, such as control units and batteries. Electrical components such as electric motors and power supply devices generate heat during operation, and more heat is generated when the power level is high. In order to obtain a reliable power tool, and in order to allow a certain operating time, it is preferred to transfer this heat from the electrical components.

[0004] Common issues associated with power tools are operational reliability and noise levels generated during operation. Furthermore, generally speaking, in today's consumer marketplace, it is advantageous for a product such as a power tool to have conditions and / or features suitable for manufacture and assembly in a cost-effective manner. Summary of the invention

[0005] It is an object of the present invention to overcome or at least alleviate at least some of the above mentioned problems and disadvantages.

[0006] According to a first aspect of the present invention, the object is achieved by a handheld power tool, which includes: an electric motor configured to provide power to a tool of the power tool; a power supply device configured to supply power to the electric motor; an air cooling path extending through at least a portion of the electric motor and at least a portion of the power supply device so as to cool the electric motor and the power supply device when air flows through the air cooling path; and a fan arranged in the air cooling path between the electric motor and the power supply device, wherein the fan is configured to generate an air flow passing through the air cooling path along a flow direction from the electric motor toward the power supply device.

[0007] Since the fan is configured to generate an air flow through the air cooling path in a flow direction from the electric motor toward the power supply unit, effective cooling of the electric motor and the power supply unit is provided. As a further result, a more reliable power tool is provided, and the electric motor and the power supply unit are allowed to operate at high power levels without becoming overheated.

[0008] During operation of the power tool, the electric motor may be the component that generates the most heat. However, since the fan is configured to generate an air flow in a flow direction from the electric motor toward the power unit, the electric motor will be most effectively cooled. This is because the electric motor is cooled using unheated ambient air. Therefore, since the fan is configured to generate an air flow in a flow direction from the electric motor toward the power unit, the electric motor is allowed to operate at high power levels without becoming overheated.

[0009] Furthermore, since the fan is arranged in the air cooling path between the electric motor and the power supply device, the fan is positioned in the power tool at a position that is more protected from being caught by objects entering the air cooling path. Therefore, as a further result, a condition for making the power tool more reliable is provided.

[0010] Furthermore, since the fan is arranged in the air cooling path between the electric motor and the power supply device, the noise generated by the fan can be attenuated in a more effective manner, thereby providing a condition for the power tool to generate less noise during operation.

[0011] Furthermore, since the power tool includes an air cooling path and since a fan is arranged in the air cooling path between the electric motor and the power supply device, a power tool having conditions and features suitable for manufacturing and assembling in a cost-effective manner is provided.

[0012] Therefore, there is provided a handheld power tool which overcomes or at least alleviates at least some of the above problems and disadvantages. As a result, the above objects are achieved.

[0013] Optionally, the electric motor is arranged to provide power to the fan. As a result, a power tool having conditions and features suitable for manufacturing and assembling in a cost-effective manner is provided, in part because a separate fan motor is no longer required. In addition, conditions are provided for a compact power tool with low weight.

[0014] Optionally, the fan is arranged on the motor shaft of the electric motor. As a result, a power tool having conditions and features suitable for manufacturing and assembling in a cost-effective manner is provided. Furthermore, conditions are provided for a compact power tool with low weight.

[0015] Optionally, the air cooling path comprises at least one inlet upstream of the electric motor and at least one outlet downstream of the power supply unit. Thus, further effective cooling of the electric motor and the power supply unit may be provided as air may be directed through and / or past these components in an efficient manner.

[0016] Optionally, the electric motor comprises a motor housing, and wherein at least a portion of the air cooling path extends through the motor housing. Thus, further effective cooling of the electric motor is provided. As a further result, a more reliable power tool is provided, wherein the electric motor is allowed to operate at higher power levels without becoming overheated.

[0017] Optionally, the electric motor comprises a conductor winding, and wherein at least a portion of the air cooling path extends through the conductor winding. The conductor winding is a component of the electric motor that generates a large amount of heat during operation. Since at least a portion of the air cooling path extends through the conductor winding, effective cooling of the conductor winding is provided. As a further result, a more reliable power tool is provided, wherein the electric motor is allowed to operate at higher power levels without becoming overheated.

[0018] Optionally, the electric motor comprises a motor shaft arranged to rotate about a motor axis, and wherein the air flow generated by the fan extends substantially parallel to the motor axis through the air cooling path at the location of the electric motor. Thus, effective cooling of the electric motor is provided, while providing for a compact power tool with low weight.

[0019] Optionally, the power supply device comprises a battery.Therefore, a user-friendly power tool is provided, which allows the battery of the power tool to be effectively cooled.

[0020] Optionally, the power supply device comprises a control unit configured to selectively supply power to the electric motor.Therefore, a power tool is provided in which the control unit of the power tool is effectively cooled.

[0021] Optionally, the power tool comprises a housing accommodating the power supply device, and wherein the housing forms at least part of the delimiting surface of the air cooling path. Thus, a power tool is provided, so that the components of the power tool are effectively cooled, and has conditions and features suitable for manufacturing and assembly in a cost-effective manner.

[0022] Optionally, the at least one inlet and / or the at least one outlet is formed by an opening in the housing.Therefore, a power tool having conditions and features suitable for manufacture and assembly in a cost-effective manner is provided.

[0023] Optionally, the housing also accommodates an electric motor and a fan. Thus, a power tool is provided which allows components of the power tool to be effectively cooled and which has conditions and features suitable for manufacture and assembly in a cost-effective manner.

[0024] Optionally, the power tool comprises at least one wall arranged to prevent air from recirculating from the outlet portion of the fan to the inlet portion of the fan. As a result, air is pumped through the air cooling path in a more efficient manner with lower pumping losses, thereby providing an electric motor and power supply unit that are further effectively cooled in a cost and energy efficient manner.

[0025] Optionally, the at least one wall is a wall of the housing.Therefore, a power tool is provided, the components of which are effectively cooled, and which has conditions and features suitable for manufacture and assembly in a cost-effective manner.

[0026] Optionally, the power tool is a handheld power tool comprising at least one handle portion. Thus, a reliable handheld power tool is provided, so that its components are effectively cooled. In addition, a handheld power tool having conditions and features that generate less noise during use is provided. In addition, a handheld power tool having conditions and features that are suitable for manufacturing and assembling in a cost-effective manner is provided.

[0027] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various aspects of the present invention, including specific features and advantages thereof, will be readily understood from the exemplary embodiments discussed in the following detailed description and accompanying drawings, in which:

[0029] Figure 1 shows a power tool according to some embodiments; and

[0030] Figure 2 Shows Figure 1 A cross section of a housing of a power tool is shown. DETAILED DESCRIPTION

[0031] Now will more fully describe the various aspects of the present invention. The same reference numerals represent the same elements throughout. For the sake of brevity and / or clarity, well-known functions or configurations need not be described in detail.

[0032] Figure 1A power tool 1 according to some embodiments is shown. According to the embodiment shown, the power tool 1 is a trimmer. The power tool 1 comprises a tool 5 in the form of a trimmer head. It should be understood that the power tool 1 shown constitutes an exemplary embodiment of the present invention, which is only limited by the appended claims. Therefore, according to the embodiments herein, the power tool 1 may be another type of power tool other than a trimmer, such as a chain saw, a circular saw, a multi-purpose tool, a hedge trimmer, a drill, a lawn mower, etc. In addition, it should be understood that according to these embodiments, the tools mentioned herein may, for example, include cutting chains, saw blades, cutting units, drill bits, etc.

[0033] The power tool 1 is an electrically driven power tool 1. The power tool 1 comprises a housing 23 and, as further explained herein, comprises an electric motor arranged in the housing 23. Furthermore, according to the illustrated embodiment, the power tool 1 comprises a battery arranged in the housing 23. The electric motor is arranged to use power from the battery to power the tool 5. According to the illustrated embodiment, the power tool 1 comprises an elongated body 2 extending between the tool 5 and the housing 23. The power tool 1 comprises a shaft extending through the elongated body 2, wherein the shaft is arranged to transfer power from the electric motor to the tool 5.

[0034] According to the embodiment shown, the power tool 1 comprises a first handle portion 29 arranged to be grasped by one hand of the user and a second handle portion 29' arranged to be grasped by the other hand of the user. The first handle portion 29 comprises a safety switch 6, which is arranged to be pressed by the palm of the user. In addition, the first handle portion 29 of the power tool 1 comprises a throttle lever 8. According to the embodiment shown, the throttle lever 8 is arranged to be pressed by one or more fingers of the user. The throttle lever 8 allows the user to control the power output by the electric motor of the power tool 1.

[0035] Figure 2 Shows Figure 1 The cross section of the housing 23 of the power tool 1 is shown. Figure 2 , the cross section is formed in a plane including a motor axis am of an electric motor 3 of the power tool. The electric motor 3 includes a motor shaft 15 arranged to rotate about the motor axis am. As described above, the electric motor 3 is configured to provide power to a tool of the power tool. According to the illustrated embodiment, the electric motor 3 is a brushless DC electric motor, also referred to as an electronically commutated motor (ECM, EC motor), or a synchronous DC motor. The power tool also includes a power supply device 7, 9 configured to supply power to the electric motor 3. According to the illustrated embodiment, the power supply device 7, 9 includes a battery 7 and a control unit 9. The control unit 9 is configured to selectively supply power to the electric motor 3. That is, according to the illustrated embodiment, the control unit 9 is arranged to supply power from the battery 7 to the electric motor 3 in an amount controlled by the throttle lever 8, such as Figure 1 The battery 7 may include a lithium-ion battery, for example.

[0036] The power tool 1 includes an air cooling path 11, 11', which extends through at least part of the electric motor 3 and at least part of the power supply device 7, 9, so as to cool the electric motor 3 and the power supply device 7, 9 when air flows through the air cooling path 11, 11'. The power tool 1 includes a fan 13, which is arranged in the air cooling path 11, 11' between the electric motor 3 and the power supply device 7, 9. According to the embodiment shown, the fan 13 is an axial flow fan arranged on the motor shaft 15 of the electric motor 3. Therefore, according to these embodiments, the electric motor 3 is arranged to provide power to the fan 13, that is, the fan 13 rotates. The fan 13 is configured to generate an air flow through the air cooling path 11, 11' along a flow direction d from the electric motor 3 toward the power supply device 7, 9. In this way, as further explained herein, effective cooling is provided to the electric motor 3 and the power supply device 7, 9.

[0037] According to the embodiment shown, the housing 23 accommodates the power supply devices 7, 9, the electric motor 3 and the fan 13. In addition, the housing 23 defines and delimits at least part of the air cooling path 11, 11' and forms at least part of the delimiting surface 25 of the air cooling path 11, 11'. The air cooling path 11, 11' includes a first inlet 17 and a second inlet 17', each of which is arranged upstream of the electric motor 3. The first inlet 17 and the second inlet 17' are each formed by an opening in the housing 23. In addition, according to the embodiment shown, the air cooling path 11, 11' includes a first outlet 19 and a second outlet 19', each of which is arranged downstream of the power supply devices 7, 9. The first outlet 19 is also Figure 1 Furthermore, the first outlet 19 and the second outlet 19' are each formed by an opening in the housing 23. Since the housing 23 accommodates the fan 13 and since the fan 13 is arranged in the air cooling path 11, 11' between the electric motor 3 and the power supply devices 7, 9, the noise generated by the fan 13 is attenuated in an effective manner.

[0038] The electric motor 3 comprises a motor housing 20 and a conductor winding 21. According to the embodiment shown, some parts of the air cooling paths 11, 11' extend through the motor housing 20 and through the conductor winding 21. Figure 2 As shown by the dashed lines showing the air cooling paths 11, 11' in FIG, a portion of the air cooling paths 11, 11' may also extend around the motor housing 20. In this way, since air can flow through the motor housing 20, through the conductor windings 21, and around the motor housing 20, the electric motor 3 is cooled in an effective manner.

[0039] from Figure 2It will be appreciated that during operation of the power tool, the fan 13 will create a pressure in the interior volume of the first housing portion 23' of the housing 23 that accommodates the electric motor 3 that is lower than the surrounding atmospheric pressure. As a result, ambient air will flow into the first inlet 17 and the second inlet 17', through the electric motor 3 and around the electric motor toward the fan 13. The air is pushed from the fan 13 toward the power supply unit 7, 9. Therefore, the fan 13 will create a pressure in the interior volume of the second housing portion 23" of the housing 23 that accommodates the power supply unit 7, 9 that is higher than the surrounding atmospheric pressure. The higher pressure in the second housing portion 23" will force air to flow out of the first outlet 19 and the second outlet 19'.

[0040] According to the embodiment shown, the power tool 1 comprises walls 27, which are arranged to prevent air from recirculating within the housing 23 from the outlet part 13" of the fan 13 to the inlet part 13' of the fan 13. These walls 27 extend essentially radially from the fan 13 and seal the internal volume of the first housing part 23' relative to the internal volume of the second housing part 23" at a position radially outside the fan 13. In this way, air is pumped through the air cooling paths 11, 11' in a more efficient manner with lower pumping losses. According to the embodiment shown, these walls 27 are inner walls of the housing 23. Therefore, the power tool can be assembled in a simple manner, and conditions are provided for manufacturing the power tool in a cost-effective manner.

[0041] like Figure 2 As shown, according to the embodiment shown, the air cooling path 11, 11' is divided into a first air cooling path portion 11 and a second air cooling path portion 11' by an inner wall 31 of the housing 23. Therefore, according to the embodiment shown, the housing includes walls 27, 31 that block air in some directions and guide air in other directions. The first air cooling path portion 11 extends through some parts of the battery 7, while the second air cooling path portion 11' extends through some parts of the control unit 9. Therefore, during operation of the power tool, some air is pushed from the fan 13 to the first outlet 19 and / or the second outlet 19' through the first air cooling path portion 11, while some air is pushed from the fan 13 to the first outlet 19 and / or the second outlet 19' through the second air cooling path portion 11'. In this way, the battery 7 and the control unit 9 are effectively cooled, respectively.

[0042] As can be understood from the above, even if the dotted line indicating the second air cooling path portion 11 ′ is led out through the second outlet 19 ′, the air flowing through the second air cooling path portion 11 ′ may flow out from the housing 23 via the first outlet 19 .

[0043] Furthermore, according to the illustrated embodiment, the flow direction d of the air flow generated by the fan 13 through the air cooling paths 11, 11' at the location of the electric motor 3 extends substantially parallel to the motor axis am. The flow direction d may be the average flow direction d of the air flow generated by the fan 13 through the air cooling paths 11, 11' at the location of the electric motor 3. The term "substantially parallel" as used herein means that the angle between the motor axis am and the flow direction d is less than 10 degrees.

[0044] It should be understood that the foregoing is an illustration of various exemplary embodiments, and the present invention is limited only by the appended claims. Those skilled in the art will recognize that the exemplary embodiments may be modified without departing from the scope of the present invention as defined by the appended claims, and that different features of the exemplary embodiments may be combined to create embodiments other than those described herein.

[0045] As used herein, the terms "comprise" or "include" are open ended and include one or more stated features, elements, steps, components or functions, but do not exclude the existence or addition of one or more other features, elements, steps, components, functions or combinations thereof.

Claims

1. A handheld power tool (1), comprising: - an electric motor (3) configured to provide power to a tool (5) of the power tool (1), - a power supply device (7, 9) configured to supply power to the electric motor (3), - an air cooling path (11, 11') extending through at least part of the electric motor (3) and at least part of the power supply device (7, 9) so as to cool the electric motor (3) and the power supply device (7, 9) when air flows through the air cooling path (11, 11'), and - a fan (13) arranged in the air cooling path (11, 11') between the electric motor (3) and the power supply device (7, 9), wherein the fan (13) is configured to generate an air flow passing through the air cooling path (11, 11') in a flow direction (d) from the electric motor (3) toward the power supply device (7, 9); The power tool (1) comprises a housing (23), the housing having a first housing portion for accommodating the electric motor (3) and a second housing portion for accommodating the power supply device (7, 9), wherein the electric motor (3) comprises a motor housing (20), and wherein a portion of the air cooling path (11, 11') extends through the motor housing (20), and wherein a portion of the air cooling path (11, 11') extends around the motor housing (20) and passes through the motor housing; The air cooling path (11, 11') comprises at least one inlet (17, 17') located upstream of the electric motor (3) and at least one outlet (19, 19') located downstream of the power supply device (7, 9), and the at least one outlet (19, 19') comprises a first outlet (19) and a second outlet (19'); Wherein, the power supply device (7, 9) comprises a battery (7); Wherein, the power supply device (7, 9) comprises a control unit (9), and the control unit is configured to selectively supply power to the electric motor (3); The air cooling path (11, 11') is divided into a first air cooling path portion (11) and a second air cooling path portion (11') by an inner wall of the housing (23); the first air cooling path portion (11) extends through some portions of the battery (7), and the second air cooling path portion (11') extends through some portions of the control unit (9), so that during operation of the handheld power tool, some air is pushed from the fan (13) through the first air cooling path portion (11) toward the first outlet (19) and / or the second outlet (19'), and some air is pushed from the fan (13) through the second air cooling path portion (11') toward the first outlet (19) and / or the second outlet (19'); wherein the electric motor (3) comprises a motor shaft (15) arranged to rotate about a motor axis (am), and wherein a flow direction (d) of the air flow generated by the fan (13) through the air cooling path (11, 11') at the location of the electric motor (3) extends substantially parallel to the motor axis (am); and Wherein, in the extension direction of the motor axis (am), the electric motor (3) and the power supply device are respectively located on opposite sides of the fan (13).

2. The handheld power tool (1) according to claim 1, wherein: The electric motor (3) is arranged to provide power to the fan (13).

3. The handheld power tool (1) according to claim 2, wherein: The fan (13) is arranged on a motor shaft (15) of the electric motor (3).

4. The handheld power tool (1) according to any one of claims 1 to 3, wherein: The electric motor (3) comprises a conductor winding (21), and wherein at least a portion of the air cooling path (11, 11') extends through the conductor winding (21).

5. The handheld power tool (1) according to claim 1, wherein: The housing (23) forms at least part of a delimiting surface (25) of the air cooling path (11, 11').

6. The handheld power tool (1) according to claim 5, wherein: The at least one inlet (17, 17') and / or the at least one outlet (19, 19') are formed by openings in the housing (23).

7. The handheld power tool (1) according to claim 5, wherein: The housing (23) also accommodates the fan (13).

8. The handheld power tool (1) according to claim 5, wherein: The power tool (1) comprises at least one wall (27) arranged to hinder the recirculation of air from an outlet portion (13'') of the fan (13) to an inlet portion (13') of the fan (13).

9. The handheld power tool (1) according to claim 8, wherein: The at least one wall (27) is a wall of the housing (23).

10. The handheld power tool (1) according to any one of claims 1 to 3, wherein: The power tool (1) is a handheld power tool (1) comprising at least one handle portion (29, 29').

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