Work equipment, in particular electrical equipment, in particular hand-held electrical equipment, and method for operating a work equipment

Abstract

A working device (1), in particular an electrical device, especially a handheld electrical device, comprises at least one working section (2), a drive (3), in particular an electric motor (4), for driving the working section (2), at least one device (5) for generating a main airflow (11), and at least one housing (6) that at least partially surrounds the drive (3) and / or the device (5) for generating the main airflow (11), and which has an air intake opening (7) and an air outlet opening (8). The air intake opening (7) and the air outlet opening (8) define an airflow path (13). The working device also comprises at least one further component (9) that is subjected to heat during operation of the electrical device. The housing (6) has at least one intake opening (10) for cooling air, which is connected to the airflow path (13) and through which a cooling airflow (12) can be directed over the heat-loaded component (9).

Description

[0001] The present invention relates to a work device, in particular an electrical device, in particular a hand-held electrical device, with at least one working section, with a drive, in particular an electric motor, for driving the working section, with at least one device for generating a main airflow, with at least one housing at least partially surrounding the drive and / or the device for generating the main airflow, which has an air intake opening and an air outlet opening, wherein the air intake opening and the air outlet opening define an airflow path, and with at least one further component that is subjected to heat during operation of the electrical device.Furthermore, the invention relates to a method for operating such a working device with at least one working section, a drive, in particular an electric motor, for driving the working section, at least one housing at least partially surrounding the drive and / or the fan wheel, and with at least one further component that is subjected to heat during operation of the electrical device, wherein an airflow is generated by means of a fan wheel, which is drawn in through an air intake opening of the housing and discharged through an air outlet opening of the housing.

[0002] From EP 2 065 128 B1, a power tool is known that can be designed, for example, as a jigsaw or router and includes an electric motor. The power tool also includes a tool, such as a saw blade. The electric motor has a cooling fan that cools the motor during operation. The power tool also has a base plate that incorporates a system for removing sawdust. For this purpose, the base plate has a blowing channel and a suction channel, which are connected to the airflow of the electric motor's cooling fan. Sawdust is blown towards a suction opening via a blowing opening, allowing it to be removed from the work area.Despite the cooling fan for the electric motor, undesirable heat generation can occur during operation of the power tool, especially if the power tool has other heat-generating components.

[0003] The object of the present invention is to further improve the power tool known from the prior art.

[0004] The problem is solved by an electric tool and a method with the features of the independent patent claims.

[0005] A working device, in particular an electrical device, especially a handheld electrical device, comprises at least one working section, a drive, in particular an electric motor, for driving the working section, at least one device for generating a main airflow, and at least one housing that at least partially surrounds the drive and / or the device for generating the main airflow, and which has an air intake opening and an air outlet opening, wherein the air intake opening and the air outlet opening define an airflow path. The working device also comprises at least one further component that is subjected to heat during operation of the electrical device.

[0006] It is proposed that the housing have at least one intake opening for cooling air, which is connected to the airflow path and allows a cooling airflow to be directed over the heat-stressed component. Because the intake opening is fluidically connected to the airflow path of the main airflow, a negative pressure is created in the area of ​​the intake opening and within the fluidic connection, which allows the intake of a cooling airflow. The intake opening is positioned such that at least a portion of the cooling airflow is directed over the heat-stressed component. This allows the heat-stressed component to be cooled, thereby reducing the overall heat generation in the working device. Failures of the working device and / or its components due to excessive heat generation can thus be avoided.

[0007] The heat-stressed component can be of various types and may, for example, include a control component, a power supply component, a working component connected to the working section, or another drive component.

[0008] The main airflow can also be designed in various ways and, for example, be a cooling airflow for the drive or another drive, or a working airflow, for example, for supplying or removing working air, for sucking up dust or chips, or for blowing off surfaces, as in the case of a leaf blower.

[0009] The working section can include a tool holder connected to the drive, such as a sprocket in the case of a chainsaw, and possibly also a working tool, such as a saw chain, a saw blade, a grinding wheel, or the like. If the main airflow is a working airflow, for example in the case of a leaf blower, the working section can also simply include a fan wheel and / or an air guide and / or an exhaust nozzle.

[0010] The same advantages can also be achieved by a method for operating a work device, in particular an electrical device, especially a handheld electrical device, for which protection is also claimed. The work device comprises at least one working section, a drive, in particular an electric motor, for driving the working section, at least one housing at least partially surrounding the drive and / or the fan wheel, and at least one further component that is subjected to heat during operation of the work device. An airflow is generated by means of a device for producing a main airflow, which is drawn in through an air intake opening of the housing and discharged through an air outlet opening of the housing. A cooling airflow is drawn in through at least one further intake opening of the housing and directed over the heat-stressed component. The heat-stressed component is thereby cooled.

[0011] It is advantageous if the device for generating the main airflow is a fan. This allows the electric motors of such equipment to be reliably cooled. Often, these fan units are integrated with the electric motor, so that the existing device for generating the main airflow can also be used to generate the cooling airflow. However, the drive could also be, for example, an internal combustion engine. In this case, the main airflow would be generated by the intake of combustion air and the expulsion of exhaust gases. The device for generating the main airflow would then be the drive itself.

[0012] It also offers advantages to have a Venturi nozzle in the flow path, with the intake opening connected to a suction port on the Venturi nozzle. This significantly improves the motive power of the main airflow used as the motive medium compared to an arrangement without a Venturi nozzle, thus making the intake of the cooling airflow particularly efficient. The Venturi nozzle can be positioned at any point along the airflow path and can, for example, be located within the air outlet or even formed by the air outlet itself.

[0013] However, if the main airflow is itself a cooling airflow, it is advantageous for the Venturi nozzle to be positioned downstream of the electric motor to be cooled. The cooling airflow, already warmed by heat dissipation from the other, heat-loaded component, thus only enters the main airflow after the electric motor, thereby preventing further heat buildup on the electric motor.

[0014] It is also advantageous if the intake opening is connected to the airflow path, particularly the suction port, via a suction duct. By arranging a suction duct within the working tool, defined flow conditions can be created, enabling the effective passage of the cooling airflow through the working tool.

[0015] It is also advantageous if the suction channel is formed, at least partially, through the housing of the tool. This eliminates the need to manufacture and install an additional component as a suction channel. Instead, the suction channel can be easily formed by corresponding recesses in the tool housing. In this way, suction channels can be manufactured cost-effectively.

[0016] In this method, it is advantageous if the cooling airflow is guided at least partially directly through the housing of the working device, in particular through a handle section and / or a finger guard section of the working device.

[0017] Advantages arise if the suction channel includes at least one suction line, preferably extending at least between the flow path, particularly the suction port, and the heat-stressed component. The suction channel can also be easily and cost-effectively constructed and installed using a clean line, such as a plastic suction hose. For this, it is only necessary to run the suction line, for example, from the suction port of the Venturi nozzle to at least the heat-stressed component, or preferably to the intake opening. It is also possible to combine such a suction line, particularly a suction hose, with sections of the housing that form the suction channel in sections.

[0018] It is also advantageous to have an air purification unit, particularly a filter element, attached to or positioned upstream of the intake opening. In this process, it is beneficial to clean the cooling airflow with an air purification unit before it passes over the heat-stressed component. This makes it possible to clean the air, which is often contaminated with dust or other impurities such as sawdust, metal shavings, and the like, preventing damage to the heat-stressed component being cooled and the device for generating the main airflow, while also keeping the airflow paths clear. Instead of or in addition to a filter element, a separator, particularly a cyclone separator, could also be used as the air purification unit.

[0019] It is also advantageous if the air purification unit is removable, especially without tools, from the work equipment. This simplifies maintenance, cleaning, and replacement of the air purification unit. Regular cleaning or replacement of the air purification unit, particularly of a filter element, ensures an effective flow of cooling air even after extended use.

[0020] It is also advantageous if the heat-stressed component is a control unit of the machine, particularly a printed circuit board (PCB). Such PCBs are usually very sensitive to heat. Heat can develop within the control units due to the currents flowing through them. Furthermore, due to their position within the component, the control units can be exposed to heat loads from adjacent components. By providing an additional intake opening and generating a cooling airflow, the control units can be efficiently cooled and the heat dissipated.

[0021] It is also advantageous if the heat-stressed component is a battery pack for powering the tool. Such battery packs also generate considerable heat during operation, particularly at the interface with the tool, which is often difficult to dissipate. Providing an air intake near the battery pack interface allows for efficient cooling of the battery pack and / or the battery housing.

[0022] In this method, it is advantageous if the cooling airflow is directed via a control unit of the working device, in particular a circuit board, and / or via a battery pack to supply power to the working device.

[0023] It is also advantageous if the tool includes a handle section and / or a finger guard section, and the suction channel is routed through this section. Particularly advantageous is the ability to form the suction channel directly through the tool housing that contains the handle section and / or finger guard section. Depending on the design of the handle section and / or finger guard section, it is also possible to integrate a suction line within the handle section and / or finger guard section.

[0024] It also offers advantages if the fan wheel is mounted directly on the motor shaft of the drive or is automatically driven along with it, thus eliminating the need for a separate drive for the fan wheel. However, it is also possible to connect the fan wheel to the motor shaft of the drive via a gearbox. This is particularly relevant if the fan wheel is not intended for cooling the drive, but rather for generating a working airflow.

[0025] It is also advantageous if the tool is a pruning saw, in particular a battery-powered pruning chainsaw, driven by an electric motor. Such tools often generate a particularly high amount of heat due to the nature of the work, which also makes it difficult to dissipate the heat from the electric motor and other heat-generating or heat-stressed components. The invention can therefore be used particularly advantageously with such tools.

[0026] Further advantages of the invention are described in the following exemplary embodiments. These show: Fig. 1 a working device with a drive, at least one further heat-stressed component and an intake opening for cooling air according to a first embodiment, Fig. 2 a working device with a drive, at least one further heat-stressed component and an intake opening for cooling air according to a second embodiment, Fig. 3 a working device with a drive, at least one further heat-stressed component and an intake opening for cooling air according to a third design, Fig. 4 a device for generating a main airflow with a main airflow and a cooling airflow according to a first embodiment in a schematic representation, Fig. 5 a device for generating a main airflow with a main airflow and a cooling airflow according to an alternative embodiment in a schematic representation, Fig. 6 a flow path with a Venturi nozzle with a main airflow and a cooling airflow according to a first embodiment in a schematic representation, Fig. 7 a flow path with a Venturi nozzle with a main airflow and a cooling airflow according to a second, alternative design in a schematic representation, as well as Fig. 8 A schematic, cutaway representation of a tool with a suction channel passing through a handle section.

[0027] In the following description of the exemplary embodiments, features that are identical and / or comparable in their design and / or function across the various figures are each designated with the same reference numerals. Furthermore, features are generally only explained in detail upon their initial mention, while subsequent exemplary embodiments focus solely on the differences compared to those already described. Unless features are explained in detail again, their design and / or function correspond to the design and function of the features already described with reference to one or more of the preceding figures. For the sake of clarity, often only one or a few identical components or features are labeled.

[0028] Fig. Figure 1 shows a schematic top view of a working device 1 according to a first embodiment. The working device 1 shown here is designed as an electric device in the form of a chainsaw. The working device 1 has a working section 2, which in this case comprises a sprocket 29 driven by a drive 3, which here is designed as an electric motor 4. During operation of the working device 1, the sprocket 29 drives a saw chain 30, which, as is known per se, is guided on a guide bar (not labeled). The working device 1 also has a front handle section 22 and a rear handle section 22, with which the working device 1 can be held and guided during operation and can also be carried when not in use.Furthermore, the work device 1 has an emergency stop switch 31, which also forms a finger guard section 23, as well as another finger guard section 23, which protects the hand at the rear handle section 22. For the power supply of the work device 1, a power supply section 32 is also provided, which can either include a mains connection or, as shown here, a battery compartment 26 for a battery pack 21.

[0029] The electric motor 4 is equipped with a fan 14, which is mounted directly on a motor shaft 24 of the electric motor 4 and forms a device 5 for generating a main airflow 11. The fan 14 serves to cool the electric motor 4, with the main airflow 11, symbolized here by two thick, dashed lines, flowing axially over the cooling fins of the electric motor 4 (not shown here). This ensures reliable cooling of the electric motor 4 during operation. The electric motor 4 is arranged in a housing 6 of the working device 1, which can be designed as a separate drive housing or as a single-piece housing 6 for the drive 3 and the working section 2, and optionally other components. The housing 6 can also be designed as a single piece with at least the rear handle section 22 and the rear finger guard section 23.The housing 6 of the working device 1 can also be made up of multiple parts and can only partially surround the electric motor 4. The housing 6 can also, for example, be at least partially formed by a fan shroud of a drive 3. The housing 6 has an air intake opening 7 through which the main airflow 11 can be drawn in, and an air outlet opening 8 through which the main airflow 11 can be discharged. The air intake opening 7 and the air outlet opening 8 define an airflow path 13 for the main airflow 11, which in this case runs between the housing 6 and the surface of the drive 3.

[0030] The working device 1 also has one or more heat-stressed components 9, which can be located at various points on the working device 1. Such heat-stressed components 9 can be, for example, control units 20, such as circuit boards, or parts of the working section 2, as well as other functional assemblies of the working device 1. The battery holder 26 and the battery pack 21 itself can also represent such heat-stressed components 9. In the present example, a control unit 20 is shown as a heat-stressed component 9.

[0031] To cool the heat-stressed component 9, an intake opening 10 is provided in the housing 6 through which cooling air can be drawn in. The intake opening 10 is connected to the airflow path 13, creating a negative pressure in the area of ​​the intake opening 10 to draw in the cooling air. The intake opening 10 is positioned such that the drawn-in cooling airflow 12, which is also represented here by a dashed arrow, can be directed over the heat-stressed component 9. This allows the heat-stressed component 9 to be cooled efficiently and with minimal effort.

[0032] Connecting the intake opening 10 to the airflow path 13 can be done in various ways, as shown by the Fig. As explained in Figures 4-8. In particular, the intake opening 10 can be connected to the airflow path 13 via the channels formed in the housing 6 and / or via a cooling line. The airflow path 13 can also be formed by components of the housing 6 and / or components or parts of the working device 1, or it can include inserted channel components. Combinations of channel components and components of the housing 6 and / or components of the working device 1 are also possible.

[0033] In the present example, the intake opening 10 is also located near the battery pack 21 and the battery holder 26. By drawing in the cooling airflow 12, at least a portion of the intake air can simultaneously be directed over the battery holder 26 and / or the battery pack 21, thus also providing them with a cooling effect. In the example shown, the fan wheel 14 is mounted directly on the motor shaft 24 of the electric motor 4, so that the fan wheel 14 is directly driven during operation. However, contrary to the illustration shown, it would also be possible to drive the fan wheel 14 with a separate electric motor 4 (not shown here).

[0034] Fig. Figure 2 shows a different embodiment of a work device 1 in a schematic top view. The work device 1 shown here is also designed as a chainsaw, but has an internal combustion engine 25 as its drive 3, as can also be seen from the spark plugs 27, which are also represented symbolically. The main airflow 11 is formed in this case by the supplied combustion air and the exhaust gases of the internal combustion engine 25 and is also represented by dotted, thick lines. As previously shown in Fig. As described in Figure 1, a front and a rear handle section 22, as well as a front and a rear finger guard section 23, are also visible. As previously described, working section 2 also includes a sprocket 29 and a saw chain 30. Working section 2 is, as also described in Figure 1, Fig. 1, connected to the motor shaft 24 of the drive 3. The energy supply unit in this case is formed by a fuel system not shown here.

[0035] The device 5 for generating a main airflow 11 is formed, according to the present example, by the drive 3 itself, in particular by a piston-cylinder unit of the internal combustion engine 25. Also shown are an air intake opening 7 and an air outlet opening 8 in the housing 6 of the working device 1, which in this case at least surrounds the drive 3. The airflow path 13 is designed in this case as an air supply channel (not labeled) and an air discharge channel (not labeled).

[0036] The heat-stressed component 9 is not further specified here and, as already described, can be a control unit 20, any auxiliary unit, or other component of the working device 1. An intake opening 10 for a cooling airflow 12 (shown here in dashed, thick lines) is arranged such that the cooling airflow 12 can be directed over the heat-stressed component 9. In particular, the intake opening 10 is located adjacent to the heat-stressed component 9.

[0037] According to the present example, the intake opening 10 is connected to the air supply duct (not labeled), which, as already mentioned, Fig. As described in section 1, this can be done in various ways and will be further explained with reference to the following figures. In contrast to the illustration shown here, the intake opening 10 could also be connected to the air discharge duct.

[0038] Fig. Figure 3 shows another embodiment of a work device 1, which in this case is designed in the form of a leaf blower. The work device 1 is also designed as an electric device and has an electric motor 4 as its drive 3. The power supply section 32 can be, as already shown in Figure 3, Fig. As described in Figure 1, the connection can be in the form of a mains connection or, as shown, in the form of a battery holder 26 for a battery pack 21. The battery pack 21 is also shown here in dashed lines. The working device 1 shown here has a one-piece housing 6 to which a one- or multi-piece blower nozzle 33 is connected.

[0039] A fan wheel 14 is also arranged on the motor shaft 24 of the electric motor 4. This simultaneously forms the working section 2 and the device 5 for generating a main airflow 11. The main airflow 11 is again represented by thick, dashed lines. To draw in the main airflow 11, the housing 6 has one or, in this case, several air intake openings 7. The main airflow 11 is then discharged through the opening of the blower nozzle 33, which here also forms the air outlet opening 8. The airflow path 13, which extends between the air intake opening 7 and the air outlet opening 8, is only partially shown here and is formed on the outlet side by the blower nozzle 33. On the inlet side, the airflow path 13 can be connected by an air supply channel, similar to that shown in Fig. 2 shown, or may also be formed by components of the housing 6 or other components of the working device 1. A heat-stressed component 9 is also provided here in the form of a control unit 20, but could also be formed by another component.

[0040] The housing 6 of the working device 1 again has an intake opening 10 through which a cooling airflow 12 can be drawn in, which is directed over the heat-stressed component 9 and thereby cools it. The intake opening 10 is fluidically connected to the airflow path 13 so that the cooling airflow 12 can be drawn in.

[0041] Various ways of connecting the intake opening 10 to the airflow path 13 are described below using the following examples. Fig. 4-7 are shown and can be used in all examples of the Fig. 1-3 will be used.

[0042] Fig. Figure 4 shows a device 5 for generating a main airflow 11 with a main airflow 11 and a cooling airflow 12 according to a first embodiment in a schematic, abbreviated representation. The device 5 for generating the main airflow 11 is not specified in detail and can, for example, be designed by a fan wheel 14, a piston-cylinder unit of an internal combustion engine 25, or in some other way. Likewise, the airflow path 13, as with respect to the Fig. 1-3 already described, include both an air supply channel and an air discharge channel, or at least be formed by components of the working device 1.

[0043] Furthermore, the housing 6 of the working device 1 and the air intake opening 7 are visible. According to the present example, the intake opening 10 is connected to the airflow path 13 of the main airflow 11 via a suction duct 17. The suction duct 17 can be formed in various ways by components of the working device 1 or include a suction line 18, such as a suction hose. In this example, the suction duct 17 opens into the airflow path 13 upstream of the device 5 for generating the main airflow 11, in the direction of flow. The suction of the main airflow 11 also creates a negative pressure in the suction duct 17, so that the cooling airflow 12 can be drawn in through the intake opening 10. As can be seen, the suction duct 17 also extends over the heat-stressed component 9, which is shown here only schematically and is not described in detail.The heat-stressed component 9 can be cooled by the cooling effect of the cooling airflow 12 passing over it.

[0044] Is the device 5 for generating the main airflow 11 a fan wheel 14 (see Fig. 1 and Fig. 3), due to the action of the fan wheel 14, air is drawn in through both the air intake opening 7 and the intake opening 10. The cooling airflow 12 absorbs heat from the heat-stressed component 9, so that it has warmed up when it meets the main airflow 11 and is conveyed together with it. If the main airflow 11 serves to cool a component or the electric motor 4 (see Fig. 1 and Fig. 3) This results in warm air being supplied to the component or the electric motor 4 via the cooling airflow 12. This could impair the cooling of the electric motor 4 or the component. Therefore, it may also be advantageous to supply the cooling airflow 12, in the direction of flow of the main airflow 11, to the airflow path 13 only after the component to be cooled or only after the electric motor 4.

[0045] According to another version, which is in Fig. As shown in Figure 5, the cooling airflow 12 is intended to be supplied to the airflow path 13 in the direction of flow of the main airflow 11 only after the device 5 for generating the main airflow 11. If the device 5 for generating the main airflow 11 is a fan wheel 14, the intake duct 17 would accordingly open on the exhaust side of the airflow path 13. If the device 5 for generating the main airflow 11 is an internal combustion engine, the intake duct 17 would accordingly open on the exhaust side of the airflow path 13, in particular into an exhaust pipe. If the main airflow 11 also serves to cool a component, it can also be designed as follows: Fig. 5. It may be advantageous to introduce the cooling airflow 12 into the airflow path 13 only after the component to be cooled, as already described in [reference]. Fig. 4 described. Furthermore, the execution corresponds to the Fig. 5 of the Fig. 4, so that the statements made there also apply here accordingly.

[0046] Fig. Figure 6 shows another embodiment of a working device 1 in a schematic, abbreviated representation. In this case, only a section of the flow path 13 of the main airflow 11 is shown. The air intake opening 7 and the air outlet opening 8, as well as the device 5 for generating the main airflow 11, are not shown. Furthermore, a part of the housing 6 with the air intake opening 7 is shown. The air intake opening 7 is located at the end of a suction duct 17, which is at least partially formed in the housing 6 of the working device 1. The suction duct 17 connects the air intake opening 7 with the airflow path 13. As can be further seen, the suction duct 17 is arranged such that the cooling airflow 12 generated by means of the air intake opening 7 again passes over a heat-stressed component 9 and is thus able to cool it.

[0047] According to the present example, a Venturi nozzle 15 is arranged in the airflow path 13. This nozzle narrows the airflow path 13 and is thereby able to increase the suction effect in the suction channel 17. For this purpose, the suction channel 17 is connected to a suction port 16 of the Venturi nozzle 15. In this case, the suction channel 17 is designed as a suction line 18 between the suction port 16 and the heat-stressed component 9. This suction line can be, for example, a suction hose or a plastic or metal pipe. The Venturi nozzle 15 can be arranged at any point within the airflow path 13 and, depending on the requirements, upstream or downstream of a drive 3 or other component to be cooled.

[0048] Fig. Figure 7 shows another embodiment of a work device 1 in a schematic, abbreviated representation. In contrast to the embodiment of the Fig. In this case, an air purification unit 19 is assigned to the intake opening 10. This unit is designed in the form of a filter element. The air purification unit 19 is preferably arranged on the working device 1 in such a way that it can be removed, cleaned, or replaced without tools. This simplifies the maintenance of the working device 1. Furthermore, the design corresponds to the Fig. 6.

[0049] Fig. Figure 8 shows another embodiment of a work device 1 in a schematic, cutaway view. The work device 1 is also designed as an electric device and has a battery compartment 26 for a battery pack 21 (not shown here). The housing 6 forms a drive housing 28 for a drive 3 (not shown here), which is similar to the one shown in Figure 8. Fig. 1 is described by means of a main airflow 11 (not shown here). Only the air intake opening 7 and the air outlet opening 8 for the main airflow 11 are shown schematically here. The airflow path 13 is also shown schematically. It should be understood that this is only an example and that the airflow path 13, as already mentioned in the Fig. The working section 1-7 can be executed in various ways through the housing 6 of the working device 1 and can be configured in various ways. The working device 1 shown here could, for example, be configured as an electric pruning saw. The working section 2 of the working device 1 is not visible here. Only a saw chain 30, which is driven by the working section 2, is shown schematically. A heat-stressed component 9 in the form of a control unit 20 is arranged here near the battery holder 26.

[0050] The working device 1 has a handle section 22 and a finger guard section 23. The suction channel 17, which connects the intake opening 10 to the airflow path 13, runs through the finger guard section 23 of the working device 1. The suction channel 17 can be designed in various ways and is advantageously formed directly by contours of the housing 6, so that no separate component for the suction channel 17 is required. However, it is also conceivable to provide the suction channel 17 in the form of a suction line 18, which connects the heat-stressed component 9 and / or the intake opening 10 to the airflow path 13. A cooling airflow 12 is drawn in through the intake opening 10, which is capable of cooling the control unit 20.

[0051] The present invention is not limited to the illustrated and described embodiments. For example, it is not necessary to have the intake opening 10 or the intake channel 17 at a larger angle than in the Fig. 4, Fig. 5 and Fig. 8 or even at a right angle as in the Fig. 6 and Fig. Figure 7 shows the connection to the airflow path 13. However, any angle at which the cooling airflow 12 enters the main airflow 11 is possible. Further modifications within the scope of the patent claims are also possible. Reference list 1 work tool 2nd work section 3 Drive 4 electric motor 5 Device for generating a main airflow 6 cases 7 Air intake opening 8 Air outlet opening 9. Heat-stressed component 10 Intake opening 11 Main airflow 12 Cooling airflow 13 Airflow path 14 Fan wheel 15 Venturi nozzles 16 Suction ports 17 Suction channel 18 Suction line 19 air purification units 20 Control unit 21 battery pack 22 Handle section 23 Finger protection section 24 Motor shaft 25 Internal combustion engine 26 Battery compartment 27 Spark plug 28 drive housings 29 chainring 30 saw chain 31 Emergency stop switches 32 Energy supply section 33 Blower nozzle QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 065 128 B1

[0002]

Claims

Working device (1), in particular electrical device, in particular hand-held electrical device, with at least one working section (2), with a drive (3), in particular an electric motor (4), for driving the working section (2), with at least one device (5) for generating a main airflow (11), with at least one housing (6) at least partially surrounding the drive (3) and / or the device (5) for generating the main airflow (11), which has an air intake opening (7) and an air outlet opening (8), wherein the air intake opening (7) and the air outlet opening (8) define an airflow path (13), and with at least one further component (9) that is subjected to heat during operation of the working device, characterized in that the housing (6) has at least one intake opening (10) for cooling air, which is connected to the airflow path (13) and with which a cooling airflow (12) can be directed over the heat-stressed component (9). Working device (1) according to the preceding claim, characterized in that the device (5) for generating the main airflow (11) is a fan wheel (14). Working device (1) according to one of the preceding claims, characterized in that a Venturi nozzle (15) is arranged in the airflow path (13) and that the intake opening (10) is connected to a suction port (16) of the Venturi nozzle (15). Working device (1) according to one of the preceding claims, characterized in that the intake opening (10) is connected to the airflow path (13), in particular the suction port (16), via a suction channel (17). Working device (1) according to one of the preceding claims, characterized in that the suction channel (17) is formed at least sectionally through the housing (6) of the working device (1). Working device (1) according to one of the preceding claims, characterized in that the suction channel (17) includes at least one suction line (18), wherein preferably the suction line (18) extends at least between the airflow path (13), in particular the suction connection (16), and the heat-stressed component (9). Working device (1) according to one of the preceding claims, characterized in that an air purification unit (19), in particular a filter element, is associated with the intake opening (10), in particular is arranged upstream. Working device (1) according to one of the preceding claims, characterized in that the air purification unit (19) is arranged on the working device (1) in a demountable manner, in particular in a demountable manner without tools. Working device (1) according to one of the preceding claims, characterized in that the heat-stressed component (9) is a control unit of the working device (1), in particular a printed circuit board. Working device (1) according to one of the preceding claims, characterized in that the heat-stressed component (9) is a battery pack (21) for supplying energy to the working device (1). Working device (1) according to one of the preceding claims, characterized in that the working device (1) includes a handle section (22) and / or a finger protection section (23) and that the suction channel (17) is guided through the handle section (22) and / or the finger protection section (23). Working device (1) according to one of the preceding claims, characterized in that the fan wheel (14) is arranged directly on a motor shaft (24) of the drive (3). Working device (1) according to one of the preceding claims, characterized in that the working device (1) is a branch saw, in particular a battery-powered branch chainsaw, wherein the drive (3) is an electric motor (4). A method for operating a work device (1), in particular an electrical device, especially a hand-held electrical device, wherein the work device (1) comprises at least one working section (2), a drive (3), in particular an electric motor (4), for driving the working section (2), at least a housing (6) at least partially surrounding the drive (3) and / or the fan wheel (14), and at least one further component (9) that is subjected to heat during operation of the work device (1), wherein a main airflow (11) is generated by a device (5) for generating a main airflow (11), which is drawn in through an air intake opening (7) of the housing (6) and discharged through an air outlet opening (8) of the housing (6), characterized in that a cooling airflow (12) is drawn in through at least one further intake opening (10) of the housing (6) and is directed over the heat-loaded component (9). Method according to the preceding claim, characterized in that the cooling airflow (12) is guided at least section by section directly through the housing (6) of the working device (1), in particular through a handle section (22) and / or a finger protection section (23) of the working device (1). Method according to one of the preceding method claims, characterized in that the cooling air flow (12) is directed via a control unit (20) of the working device (1), in particular a circuit board, and / or via a battery pack (21) to supply energy to the working device (1). Method according to one of the preceding method claims, characterized in that the cooling air flow (12) is cleaned with an air purification unit (19) before it is passed over the heat-stressed component (9).

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