Handheld power tool comprising an air cooling system

Abstract

A handheld power tool (1) is disclosed comprising a motor (3) configured to power a tool of the handheld power tool (1), wherein the power tool (1) comprises a fan housing (5) and a fan unit (7). The fan housing (5) comprises an inlet (9) and three separate outlets (o1, o2, o3), wherein the fan unit (7) is arranged to rotate in the fan housing (5) during operation of the power tool (1) to generate an airflow from the inlet (9) into each of the three separate outlets (o1, o2, o3). The power tool (1) further comprises three separate air passages (p1, p2, p3) each connected to one of the three separate outlets (o1, o2, o3). Each of the three separate air passages (p1, p2, p3) is configured to cool a respective arrangement (a1, a2, a3) of the power tool (1).

Description

[0001] Handheld Power Tool Comprising an Air Cooling System

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a handheld power tool comprising a motor configured to power a tool of the handheld power tool.

[0004] BACKGROUND

[0005] Today, there are many kinds of handheld power tools available on the market. Examples are chain saws, circular saws, and various types of trimmers, including hedge- and combi- trimmers. Handheld power tools are for example used in industry, construction, and home gardening, as well as for various household and property maintenance tasks.

[0006] A common feature of handheld power tools is that they comprise a tool which can be driven by a power source other than solely manual labour. The power source may for example comprise a motor, such as a combustion engine, an electric motor, a pneumatic motor, or the like. Traditionally, handheld power tools such as chain saws, circular saws, trimmers, hedge trimmers, and combi-trimmers, have typically been powered by combustion engines. These engines are most often compact two-stroke internal combustion models that provide a great power-to-weight ratio as compared to other types of engines.

[0007] Nonetheless, the introduction of high-capacity and high-discharge batteries, such as lithium- ion batteries, has led to a shift towards power tools with electric motors. These batteries help electric power tools compete in performance with those comprising combustion engines.

[0008] However, some electrically driven power tools alternatively or additionally comprise an electrical connection for connecting the power tool to an external electric power supply. Electric motors provide several advantages over combustion engines especially when it comes to emission levels, efficiency, noise levels, and the like.

[0009] To meet consumer and professional demands, many power tools are equipped with high- performance electric motors, which requires power supply arrangements, such as electrical wires, contacts, control units, and batteries, which are capable of delivering high power for extended durations of time. Such electrical components, particularly motors and power supply units, generate heat during operation and more heat is generated when the power level is high. The generated heat must be transferred from these components in an efficient manner to ensure reliability and operational longevity of the power tool. Likewise, an internal combustion engine produces a lot of heat during operation which must be transferred from the engine in an efficient manner to ensure reliability and operational longevity of the engine. Moreover, handheld power tools normally comprise other types of arrangements than the motor that require cooling during operation of the handheld power tool to sustain the functionality and the operational life-span handheld power tool. Examples are batteries, battery connections, electrical connection assemblies, electrical components, control arrangements, power electronics, motors, user interface devices, transmission assemblies, fuel systems, ignition systems, cylinders, lubricant systems, and the like.

[0010] Handheld power tools typically comprise an air cooling system, which includes a fan assembly designed to dissipate heat from the motor and other arrangements by circulating air through an internal space of the power tool. Liquid cooling systems are generally not used in handheld power tools due to their added weight, complexity, and costs. In most designs, both the motor and arrangements requiring cooling are positioned to be cooled by the airflow within the internal space. Usually, the air flows through the internal space of the power tool in a chaotic and uncontrolled manner.

[0011] Handheld power tools of various types are associated with some mutual problems. One problem is to ensure sufficient cooling of the motor of the handheld power tool, and of the additional arrangements that require cooling, at various operational conditions of the handheld power tool. As indicated above, insufficient cooling of one or more arrangements of the handheld power tool may reduce the operational lifespan of the handheld power tool, and operational reliability is a major concern for handheld power tools. In addition, insufficient cooling of one or more arrangements of a handheld power tool may reduce the operational efficiency, and / or available power output, of arrangements of the power tool, such as of a motor of the power tool.

[0012] Moreover, handheld power tools are typically used in dusty and dirty environments and the operation of the tool of the handheld power tool may generate a lot of dust, dirt, and debris. Therefore, a common problem of a handheld power tool is clogging of various parts of the internal space during operation of a handheld power tool. Accumulated dust, dirt, or debris can significantly reduce the cooling efficiency of various parts and arrangements of the handheld power tool.

[0013] Another problem associated with handheld power tools comprising an air cooling system is recirculation of air within the air cooling system. Recirculation of air within an air cooling system can reduce the cooling efficiency of various parts of the system because many parts of the internal space of the power tool will be subjected to already heated air.

[0014] Still other problems with handheld power tools of various types are packing problems. That is, from a consumer / user perspective, it is an advantage if the handheld power tool can be made compact and lightweight.

[0015] SUMMARY

[0016] It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks. The object is achieved by the subject-matter of the appended independent claim(s).

[0017] According to an aspect of the present disclosure, the object is achieved by a handheld power tool comprising a motor configured to power a tool of the handheld power tool. The power tool further comprises a fan housing and a fan unit, wherein the fan housing comprises an inlet and three separate outlets. The fan unit is arranged to rotate in the fan housing during operation of the power tool to generate an airflow from the inlet into each of the three separate outlets. The power tool further comprises three separate air passages each connected to one of the three separate outlets, wherein each of the three separate air passages is configured to cool a respective arrangement of the power tool.

[0018] Thereby, a handheld power tool is provided in which the three separate air passages can cool a respective arrangement without using air that is preheated by another of the respective arrangements. In other words, it can be ensured that the arrangements, cooled by the three separate air passages, are cooled in a parallel manner without any recirculation of air between the arrangements. Accordingly, phrased differently, conditions are provided for cooling at least three different arrangements in a parallel manner without any recirculation of air between the arrangements. Thereby, an efficient cooling of each of the arrangements can be ensured at various operational states of the handheld power tool.

[0019] Moreover, a handheld power tool is provided in which the geometry and design of the three separate air passages can be adapted to meet cooling requirements of different types of arrangements of different types and configurations of handheld power tools in a simple and cost-efficient manner.

[0020] Furthermore, since the fan housing comprises the three separate outlets, and since the power tool comprises three separate air passages each connected to one of the three separate outlets, conditions are provided for reducing the likelihood of clogging in the air passages the handheld power tool. This is because the geometry and design of the air passages are easily adaptable, allowing for a sufficient airflow rate through each of the three passages to avoid accumulation of matter therein. As a result, conditions are provided for operating the power tool for extended operational periods before the handheld power tool requires cleaning or servicing.

[0021] Accordingly, due to the features of the power tool, efficient cooling of the arrangements of the power tool can be ensured during extended operational periods at various operational conditions of the power tool.

[0022] Accordingly, a handheld power tool is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0023] Optionally, the motor of the power tool is an electric motor, and wherein a first air passage of the three separate air passages is configured to cool the motor. Thereby, conditions are provided for an environmentally friendly power tool capable of generating low noise levels during operation while ensuring efficient cooling of the electric motor at various operational states of the electric motor for extended operational periods.

[0024] Optionally, the power tool comprises a battery compartment configured to accommodate a battery for supplying electricity to the motor, and wherein a second air passage of the three separate air passages is configured to cool the battery compartment. Thereby, conditions are provided for a user-friendly power tool while ensuring efficient cooling of the battery compartment, as well as a battery accommodated therein, at various operational states of the power tool for extended operational periods.

[0025] Optionally, the power tool comprises a control arrangement, and wherein a third air passage of the three separate air passages is configured to cool the control arrangement. Thereby, efficient cooling of the control arrangement can be ensured at various operational states of the power tool for extended operational periods.

[0026] Optionally, the motor of the power tool is an electric motor, and wherein the control arrangement comprises power electronics configured to regulate the supply of electricity to the motor. Thereby, conditions are provided for an environmentally friendly power tool capable of generating low noise levels during operation, while efficient cooling of the power electronics can be ensured at various operational states of the power tool for extended operational periods.

[0027] Optionally, the fan unit is connected to an output shaft of the motor. Thereby, a simple and efficient powering of the fan unit can be provided in a cost-efficient manner.

[0028] Optionally, the fan unit is a radial fan unit. Thereby, a high operational efficiency of the fan unit can be ensured.

[0029] Optionally, a first outlet of the three separate outlets forms an axial outlet. Thereby, conditions are provided for alleviating packing problems in the handheld power tool, thereby providing conditions for a compact power tool, while being able to cool at least three different arrangements in a parallel manner.

[0030] Optionally, the first outlet is formed by a number of apertures provided in a wall of the fan housing. Thereby, conditions are provided for a simple and compact fan housing, while being able to cool at least three different arrangements in a parallel manner.

[0031] Optionally, the fan housing comprises a number of air guide members each arranged adjacent to one aperture of the number of apertures, and wherein the number of air guide members is arranged to divert the airflow through the first outlet. Thereby, the total operational efficiency of the fan unit can be improved. Moreover, a sufficient and steady airflow rate can be ensured through the first outlet at various operational conditions of the power tool while also being able to cool at least three different arrangements in a parallel manner.

[0032] Optionally, the fan unit comprises a number of fan blades, and wherein the radial extension of the number of fan blades is greater than a radial distance between a rotation axis of the fan unit and radially inner delimiting walls of the number of apertures. Thereby, a sufficient airflow rate through the first outlet of the fan housing can be further ensured at various operational conditions of the power tool while also being able to ensure sufficient airflow rates into the remaining outlets of the fan housing.

[0033] Optionally, the fan unit comprises an axial end disc, and wherein the axial end disc faces the wall of the fan housing. Thereby, a high operational efficiency of the fan unit can be further ensured, while being able to cool at least three different arrangements in a parallel manner. Optionally, the radial extension of the axial end disc is smaller than a radial distance between a rotation axis of the fan unit and radially inner delimiting walls of the number of apertures. Thereby, a sufficient airflow rate through the first outlet of the fan housing can be further ensured at various operational conditions of the power tool.

[0034] Optionally, the motor of the power tool is an electric motor, wherein the first outlet is connected to a first air passage of the three separate air passages, and wherein the first air passage is configured to cool the motor. Thereby, conditions are provided for an environmentally friendly power tool capable of generating low noise levels during operation, while efficient cooling of the electric motor can be ensured at various operational states of the power tool for extended operational periods.

[0035] Optionally, a second outlet of the three separate outlets forms a radial outlet, a tangential outlet, or a combination therebetween. Thereby, conditions are provided for alleviating packing problems in the handheld power tool, thereby providing conditions for a compact power tool, while being able to cool at least three different arrangements of the power tool in a parallel manner.

[0036] Optionally, the power tool comprises a battery compartment configured to accommodate a battery for supplying electricity to the motor, wherein the second outlet is connected to a second air passage of the three separate air passages, and wherein the second air passage is configured to cool the battery compartment. Thereby, conditions are provided for an environmentally friendly power tool, while efficient cooling of the battery compartment, as well as a battery accommodated therein, can be ensured at various operational states of the power tool for extended operational periods.

[0037] Optionally, a third outlet of the three separate outlets forms a radial outlet, a tangential outlet, or a combination therebetween. Thereby, conditions are provided for alleviating packing problems in the handheld power tool, thereby providing conditions for a compact power tool, while being able to cool at least three different arrangements of the power tool in a parallel manner.

[0038] Optionally, the power tool comprises a control arrangement, wherein the third outlet is connected to a third air passage of the three separate air passages, and wherein the third air passage is configured to cool the control arrangement. Thereby, conditions are provided for an efficient cooling of the control arrangement at various operational states of the power tool for extended operational periods. Optionally, the power tool comprises three separate air outlets each configured to discharge air from one of the three separate air passages to the surroundings. Thereby, an efficient discharge of air from the three separate air passages to the surroundings can be ensured while avoiding any internal mixing of air from the three separate air passages. In this manner, an efficient cooling of various parts of the handheld power tool can be further ensured.

[0039] Optionally, the power tool is configured as one selected from the group consisting of: a chainsaw, a power cutter, a trimmer, a hedge trimmer, a combi-trimmer, and a leaf / debris blower. Thereby, a power tool configured as one selected from the group above is provided having at least some of the above-mentioned advantages.

[0040] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Various aspects of the present disclosure, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0043] Fig. 1 illustrates a first perspective view of a handheld power tool according to some embodiments,

[0044] Fig. 2 illustrates a second perspective view of the handheld power tool illustrated in Fig. 1, Fig. 3 illustrates a first perspective view of a fan assembly of a cooling system of the handheld power tool illustrated in Fig. 1 and Fig. 2,

[0045] Fig. 4 illustrates a second perspective view of the fan assembly illustrated in Fig. 3, in which a front portion of a fan housing has been omitted for reasons of visibility,

[0046] Fig. 5 illustrates a schematic representation of the cooling system of the handheld power tool illustrated in Fig. 1 and Fig. 2,

[0047] Fig. 6 illustrates a perspective view of a first side of a fan housing of the cooling system of the handheld power tool illustrated in Fig. 1 and Fig. 2, and

[0048] Fig. 7 illustrates a perspective view of a second side of the fan housing of the cooling system of the handheld power tool illustrated in Fig. 1 and Fig. 2.

[0049] DETAILED DESCRIPTION Aspects of the present disclosure will now be described more fully. Like reference signs refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0050] Fig. 1 illustrates a first perspective view of a handheld power tool 1 according to some embodiments of the present disclosure. For reasons of brevity and clarity, the handheld power tool 1 is in some places herein simply referred to as “the power tool 1”. The feature that the power tool 1 is handheld means that the power tool 1 is configured to be supported by one or two hands of a user during operation thereof.

[0051] According to the illustrated embodiments, the power tool 1 comprises a first and a second handle hi , h2. The second handle h2 is separate from the first handle hi and is arranged at a distance from the first handle hi . The power tool 1 is configured to be supported via each of the first and second handles hi, h2 during operation of the power tool 1. In other words, the power tool 1 is configured to be supported by two hands of a user during operation of the power tool 1, i.e. , is configured to be supported by one hand grabbing the first handle hi and the other hand grabbing the second handle h2. According to further embodiments, the power tool 1 may comprise one handle only.

[0052] The power tool 1 comprises a tool portion 30’ for the attachment of a tool to the power tool 1. The tool of the power tool 1 is not illustrated in Fig. 1 for reasons of brevity. According to the illustrated embodiments, the power tool 1 is a chainsaw. Therefore, according to the illustrated embodiments, the tool portion 30’ of the power tool 1 is configured for the connection of a tool in the form of a guide bar and a cutting chain, wherein the cutting chain is movably arranged around the guide bar.

[0053] However, according to further embodiments, the power tool 1, as referred to herein, may be another type of handheld power tool, such as a power cutter, a trimmer, a hedge trimmer, a combi-trimmer, and a leaf / debris blower. Obviously, according to such embodiments, the power tool 1 may comprise another type of tool portion 30’ for the connection of another type of tool than a cutting bar and a cutting chain, such as for example a saw blade, a trimmer head, a hedge trimmer cutting assembly, a fan assembly, or the like.

[0054] A combi-trimmer refers to a type of multifunctional gardening tool that combines several functions into one device, making it versatile for various tasks. A combi-trimmer typically has a base unit with a motor and interchangeable attachments that can be swapped out depending on the task to be performed, such as trimming grass, cutting brush, or pruning hedges.

[0055] Fig. 2 illustrates a second perspective view of the handheld power tool 1 illustrated in Fig. 1. As indicated in Fig. 2, the power tool 1 comprises a motor 3. The motor 3 is configured to power a tool of the power tool 1. Accordingly, the motor 3 is operably connected to the tool portion 30’ of the power tool 1 , indicated in Fig. 1 , and is configured to power a tool connected thereto. Since the power tool according to the illustrated embodiments is a chainsaw, the motor 3 is configured to rotate a cutting chain around a guide bar attached to the tool portion 30’ of the power tool 1 as explained with reference to Fig. 1 above. Below, simultaneous reference is made to Fig. 1 and Fig. 2, if not indicated otherwise.

[0056] According to the illustrated embodiments, the motor 3 of the power tool 1 is an electric motor. Moreover, the power tool 1 comprises a battery compartment 11 configured to accommodate a battery 13 for supplying electricity to the motor 3. As an alternative, or in addition, the power tool 1 may comprise an electrical connection assembly for the electrical connection of the power tool to an external electric power supply.

[0057] Moreover, according to some embodiments of the present disclosure, the power tool 1 may comprise another type of motor than an electric motor, such as an internal combustion engine. In such embodiments, the motor of the power tool 1, as referred to herein, may be a small sized two-stroke internal combustion engine or a small sized four stroke internal combustion engine. The term “small sized” in this context may encompass that the internal combustion engine has an engine displacement of less than 250 cubic centimetres. In embodiments in which the motor of the power tool 1 is a combustion engine, the power tool may further comprise a fuelling system, comprising a fuel tank, a fuel pump, a carburettor, or a number of fuel injectors. Moreover, according to such embodiments, the power tool 1 may comprise one or more further engine-related systems such as an ignition system, an engine lubricant system, and the like.

[0058] As indicated in Fig. 1 and Fig. 2, the power tool 1 comprises a cooling system 6. As is explained in greater detail below, the cooling system 6 is an air cooling system. In Fig. 1, three separate air outlets oT, o2’, o3’ of the cooling system 6 can be seen. As is explained in greater detail below, each of the three separate air outlets oT, o2’, o3’ is configured to discharge air to the surroundings from one of three separate air passages arranged inside the power tool 1. The cooling system 6 further comprises an air inlet 9’, which is indicated in Fig. 2. Fig. 3 illustrates a first perspective view of a fan assembly 4 of the cooling system 6 of the handheld power tool 1 illustrated in Fig. 1 and Fig. 2. The fan assembly 4 comprises a fan housing 5 and a fan unit 7. The fan housing 5 comprises an inlet 9 and three separate outlets o1 , o2, o3. In Fig. 3, one outlet o1 of the three separate outlets o1, o2, o3 is hidden behind the fan housing 5. The position of the first outlet o1 has been indicated with an arrow provided with the reference sign “o1”. The inlet 9 of the fan housing 5 is arranged at the air inlet 9’ of handheld power tool 1 indicated in Fig. 2.

[0059] The fan unit 7 is arranged to rotate around a rotation axis Ax in the fan housing 5 during operation of the power tool 1 to generate an airflow from the inlet 9 into each of the three separate outlets o1, o2, o3.

[0060] Fig. 4 illustrates a second perspective view of the fan assembly 4 illustrated in Fig. 3, in which a front portion of the fan housing 5 has been omitted for reasons of visibility. The front portion of the fan housing 5 is configured to face the air inlet 9’ of the cooling system 6 of the handheld power tool 1 indicated in Fig. 2.

[0061] As is best seen in Fig. 4, according to the illustrated embodiments, the fan unit 7 is a radial fan unit, i.e. , a fan unit configured to pump air at a substantially right angle to the inlet 9. According to the illustrated embodiments, the direction of the inlet 9, or expressed more accurately, a direction of an intended main air flow direction towards the inlet 9 of the fan housing 5, substantially coincides with the rotation axis Ax of the fan unit 7. According to further embodiments, the fan unit 7 may be another type of fan unit, such as an axial fan unit, or a mixed fan design operating both axially and radially relative to the inlet 9 of the fan assembly 4.

[0062] All of the three separate outlets o1, o2, o3 of the fan housing 5 are visible in Fig. 4. The feature that the outlets o1 , o2, o3 are separate means that each of the outlets o1 , o2, o3 are separate from, i.e., distinct from, the other outlets o1 , o2, o3 of the fan housing 5. The three separate outlets o1, o2, o3 are in some places herein referred to as a first outlet o1, a second outlet o2, and a third outlet o3.

[0063] Fig. 5 illustrates a schematic representation of the cooling system 6 of the handheld power tool 1 illustrated in Fig. 1 and Fig. 2. In Fig. 5, the fan assembly 4 of the cooling system 6 is illustrated as viewed in a direction coinciding with the rotation axis Ax of the fan unit 7. Also in Fig. 5, the front portion of the fan housing 5 has been removed for reasons of visibility.

[0064] Below, simultaneous reference is made to Fig. 1 - Fig. 5, if not indicated otherwise.

[0065] As seen in Fig. 5, the cooling system 6 of the power tool 1 comprises three separate air passages p1, p2, p3. The feature that the three air passages p1, p2, p3 are separate means that each air passage p1, p2, p3 is separate from, i.e. , distinct from, the other air passages p1 , p2, p3 of the cooling system 6.

[0066] Moreover, as seen in Fig. 5, each air passage p1, p2, p3 is connected to one of the three separate outlets o1, o2, o3. Furthermore, as is further explained herein, each of the three separate air passages p1 , p2, p3 is configured to cool a respective arrangement a1 , a2, a3 of the power tool 1. In other words, the handheld power tool 1 comprises three separate arrangements a1 , a2, a3 each configured to be cooled by a separate air passage p1 , p2, p3.

[0067] In this manner, each of the three separate arrangements a1 , a2, a3 can be cooled without using air that is already preheated by another of the three separate arrangements a1 , a2, a3. In other words, it can be ensured that the three separate arrangements a1, a2, a3 are cooled in a parallel manner without any recirculation of air between the three separate arrangements a1 , a2, a3 inside the handheld power tool 1. Thereby, an efficient cooling of each of the three separate arrangements a1, a2, a3 can be ensured at various operational states of the handheld power tool 1, as is further explained herein.

[0068] Furthermore, since the fan housing 5 comprises the three separate outlets o1 , o2, o3, and since the handheld power tool 1 comprises three separate air passages p1, p2, p3 each connected to one of the three separate outlets o1, o2, o3, conditions are provided for reducing the likelihood of clogging of matter in the air passages p1, p2, p3 the handheld power tool 1.

[0069] In some places herein, the three separate air passages p1, p2, p3 are referred to as a first air passage p1, a second air passage p2, and a third air passage p3. Likewise, in some places herein, the three separate arrangements a1, a2, a3 are referred to as a first arrangement a1, a second arrangement a2, and a third arrangement a3. According to the illustrated embodiments, the first arrangement a1 comprises the motor 3, the second arrangement a2 comprises the battery compartment 11, and the third arrangement a3 comprises a control arrangement 21 of the handheld power tool 1. However, according to further embodiments, each of the first, second, and third arrangement a1 , a2, a3, as referred to herein, may comprise one or more other types of arrangements. Purely as examples, such one or more other types of arrangements may comprise one or more of a motor, an electric motor, a battery compartment, a battery, an electrical connection assembly, a number of electrical components, a control arrangement, power electronics, a user interface, a combustion engine, a transmission assembly, a fuel system, an ignition system, a cylinder, a lubricant system, or the like.

[0070] The first outlet o1 of the fan housing 5 is connected to the first air passage p1 and the first air passage p1 is arranged in heat exchanging contact with the first arrangement a1. As explained above, according to the illustrated embodiments, the first arrangement a1 comprises the motor 3. Thus, according to the illustrated embodiments, the first air passage p1 of the three separate air passages p1 , p2, p3 is configured to cool the motor 3. As is explained in greater detail below, according to the illustrated embodiments, the first outlet o1 forms an axial outlet which means that air is flowing through the first outlet o1 into the first air passage p1 in directions coinciding with viewing directions of Fig. 5. Moreover, in the schematic representation of the cooling system 6 illustrated in Fig. 5, the flow direction through the first air passage p1 coincides with the rotation axis Ax of the fan unit 7, i.e. , coincides with the rotation axis Ax of the fan unit 7.

[0071] According to the illustrated embodiments, the first air passage p1 extends through the motor 3. Since the motor 3 is an electric motor according to the illustrated embodiments, the first air passage p1 may extend through, and / or past, wire windings of the electric motor. Moreover, the first air passage p1 may extend through a space between a stator and a rotor of the motor 3. As an alternative, or in addition, the first air passage p1 may extend around at least part of an external casing of the motor 3. The air outlet oT of the first air passage p1 is schematically indicated in Fig. 5 and is also seen and is indicated in Fig. 1.

[0072] The second outlet o2 of the fan housing 5 is connected to the second air passage p2 and the second air passage p2 is arranged in heat exchanging contact with the second arrangement a2. As explained above, according to the illustrated embodiments, the second arrangement a2 comprises the battery compartment 11. Thus, according to the illustrated embodiments, the second air passage p2 of the three separate air passages p1, p2, p3 is configured to cool the battery compartment 11 of the handheld power tool 1, and therefore also a battery 13 accommodated in the battery compartment 11. The air outlet o2’ of the second air passage p2 is schematically indicated in Fig. 5 and is also seen and is indicated in Fig. 1 and Fig. 2. The third outlet o3 of the fan housing 5 is connected to the third air passage p3 and the third air passage p3 is arranged in heat exchanging contact with the third arrangement a3. As explained above, according to the illustrated embodiments, the third arrangement a3 comprises the control arrangement 21 of the handheld power tool 1. In other words, according to the illustrated embodiments, the third air passage p3 of the three separate air passages p1, p2, p3 is configured to cool the control arrangement 21. The air outlet o3’ of the third air passage p3 is schematically indicated in Fig. 5 and is also seen and is indicated in Fig. 1.

[0073] According to the illustrated embodiments, the control arrangement 21 of the handheld power tool 1 comprises power electronics 23 configured to regulate the supply of electricity to the motor 3. In more detail, according to the illustrated embodiments, the power electronics 23 is configured to regulate the supply of electricity to the motor 3 based on an actuator position of a throttle actuator 25 of the handheld power tool 1. The throttle actuator 25 is seen and is indicated in Fig. 2. According to the illustrated embodiments, the throttle actuator 25 is arranged at the first handle hi of the handheld power tool 1.

[0074] The control arrangement 21 of the handheld power tool 1 may as an alternative to the power electronics 23, or in addition to the power electronics 23, comprise one or more further electrical components including one or more of a resistor, a memory unit, a processor, a Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, an Application Specific Integrated Circuit (ASIC), a circuit for digital signal processing (digital signal processor, DSP), a microcomputer, a programmable logic unit, a microprocessor, or any other device capable of electronically performing operations in a defined manner, or other processing logic that may interpret and execute instructions.

[0075] According to the illustrated embodiments, the fan unit 7 is connected to an output shaft 3’ of the motor 3. In more detail, according to the illustrated embodiments, the fan unit 7 is connected to the output shaft 3’ of the motor 3 such that the rotation axis Ax of the fan unit 7 coincides with the rotation axis of the output shaft 3’ of the motor 3. The fan unit 7 may be arranged on the output shaft 3’ of the motor 3, or on a separate shaft, wherein the separate shaft is connected or attached to the output shaft 3’ of the motor 3. According to some further embodiments, the fan unit 7 may be powered by a separate motor, such as by a separate electric motor.

[0076] According to the illustrated embodiments, each of the second and third outlets o2, o3 forms a radial / tangential outlet which means that a main airflow direction m2, h3 through the outlet o2, o3 is substantially parallel to a rotation plane Rp of the fan unit 7. The rotation plane Rp of the fan unit 7 is perpendicular to the rotation axis Ax of the fan unit 7. According to further embodiments, the angle between a rotation plane Rp of the fan unit 7 and a main airflow direction m2, m3 through one or both of the second and third outlets o2, o3 may be less than 40 degrees or is less than 15 degrees.

[0077] Moreover, according to some further embodiments of the present disclosure, one or both of the second and third outlets o2, o3 may be a radial outlet, a tangential outlet, and axial outlet, or any combination therebetween. A radial outlet is an outlet in which the main outflow direction through the outlet coincides with a radial direction of the fan unit 7 whereas a tangential outlet is an outlet in which the main outflow direction through the outlet coincides with a tangential direction of the fan unit 7.

[0078] Fig. 6 illustrates a perspective view of a first side of the fan housing 5 of the cooling system 6 of the handheld power tool 1 illustrated in Fig. 1 and Fig. 2. Also in Fig. 6, the front portion of the fan housing 5 has been omitted for reasons of visibility. The first side of the fan housing 5 faces the air inlet 9’ of handheld power tool 1 indicated in Fig. 2.

[0079] As is best seen in Fig. 6, and as is also indicated in Fig. 4 and Fig. 5, according to the illustrated embodiments, the first outlet o1 is formed by a number of apertures 15 provided in a wall 5’ of the fan housing 5. According to the illustrated embodiments, the first outlet o1 is formed by six apertures 15 provided in the wall 5’ of the fan housing 5. However, according to further embodiments, the first outlet o1 may be formed by another number of apertures 15 provided in the wall 5’ of the fan housing 5, such as a number within the range of 1 - 30, or within the range of 3 - 10.

[0080] In Fig. 6, a radial distance r15 between the rotation axis Ax of the fan unit 7 and radially inner delimiting walls 15’ of the number of apertures 15 is indicated. The radial distance r15 between the rotation axis Ax of the fan unit 7 and the radially inner delimiting walls 15’ of the number of apertures 15 can be measured between the radially inner delimiting walls 15’ and the rotation axis Ax in a plane perpendicular to the rotation axis Ax. The radial distance r15 between the rotation axis Ax of the fan unit 7 and the radially inner delimiting walls 15’ of the number of apertures 15 is also indicated in Fig. 5.

[0081] As is indicated in Fig. 4 and Fig. 5, the fan unit 7 comprises a number of fan blades 8. Moreover, as is indicated in Fig. 5, according to the illustrated embodiments, the radial extension r8 of the number of fan blades 8 is greater than the radial distance r15 between the rotation axis Ax of the fan unit 7 and the radially inner delimiting walls 15’ of the number of apertures 15. In this manner, an efficient air pumping action can be ensured through the number of apertures 15 of the first outlet o1.

[0082] As is indicated in Fig. 4 and Fig. 5, according to the illustrated embodiments, the fan unit 7 comprises an axial end disc 10. The axial end disc 10 faces the wall 5’ of the fan housing 5. Moreover, as is indicated in Fig. 5, the radial extension r10 of the axial end disc 10 is smaller than the radial distance r15 between the rotation axis Ax of the fan unit 7 and the radially inner delimiting walls 15’ of the number of apertures 15. Thereby, an efficient air pumping action can be ensured through the number of apertures 15 of the first outlet o1. Furthermore, the axial end disc 10 can improve the operational efficiency of the fan unit 7 through a reduced turbulence of air flowing in radial directions between the blades 8, especially in a boundary layer close to the axial end disc 10.

[0083] Fig. 7 illustrates a perspective view of a second side of the fan housing 5 of the cooling system 6 of the handheld power tool 1 illustrated in Fig. 1 and Fig. 2. Also in Fig. 7, the front portion of the fan housing 5 has been omitted. The second side of the fan housing 5 faces the motor 3 and the first air passage p1 in the schematic representation of the cooling system 6 illustrated in Fig. 5.

[0084] As can be seen in Fig. 7, according to the illustrated embodiments, the fan housing 5 comprises a number of air guide members 17. The air guide members 17 may also be referred to as guide vanes, stator vanes, or stator blades. According to the illustrated embodiments, the number of air guide members 17 protrudes out from the second side of the fan housing 5 and may protrude at least partially into the first air passage of the cooling system of the power tool.

[0085] According to the illustrated embodiments, the fan housing 5 comprises four air guide members 17. However, according to further embodiments, the fan housing 5 may comprise another number of air guide members 17, such as a number within the range of 1 - 20, or within the range of 3 - 10.

[0086] According to the illustrated embodiments, each air guide member 17 of the number of air guide members 17 is arranged adjacent to one aperture 15 of the number of apertures 15. The number of air guide members 17 is arranged to divert the airflow through the first outlet o1. Due to the number of air guide members 17, the total operational efficiency of fan assembly can be improved. Moreover, a sufficient and steady airflow rate can be ensured through the first outlet o1 at various operational conditions of the power tool.

[0087] As mentioned above, according to the illustrated embodiments, the first outlet o1 forms an axial outlet. The wording axial outlet, as used herein, may mean that the angle between a main airflow direction ml through the outlet o1 and a rotation axis Ax of the fan unit 7 is less than 40 degrees or is less than 15 degrees, at least when measured at a certain distance from the outlet o1. According to further embodiments, the first outlet o1 may form a radial outlet, a tangential outlet, or any combination between a radial, tangential, and axial outlet.

[0088] The following is explained with simultaneous reference to Fig. 1 - Fig. 7. As explained above, and as is indicated in Fig. 1, according to the illustrated embodiments, the power tool 1 comprises three separate air outlets oT, o2’, o3’ each configured to discharge air from one of the three separate air passages p1 , p2, p3 to the surroundings. The air outlet o1 ’ of the first air passage p1 may be referred to as a first air outlet oT, the air outlet o2’ of the second air passage p2 may be referred to as a second air outlet o2’, and the air outlet o3’ of the third air passage p3 may be referred to as a third air outlet o3’.

[0089] According to the illustrated embodiments, the first air outlet oT is formed by an aperture in an outer casing of the handheld power tool 1 located adjacent to an attachment portion of the second handle h2. However, according to further embodiments, the first air outlet oT may be formed by a plurality of apertures and the first air outlet oT may be positioned on the handheld power tool 1 differently than as depicted in Fig. 1.

[0090] The second air outlet o2’ of the handheld power tool 1 is visible in Fig. 1 and in Fig. 2. According to the illustrated embodiments, the second air outlet o2’ is formed by a plurality of apertures provided in a section of the handheld power tool 1 located adjacent to a user interface assembly 27 of the handheld power tool 1. The user interface assembly 27 of the handheld power tool 1 is indicated in Fig. 2.

[0091] However, according to further embodiments, the second air outlet o2’ of the handheld power tool 1 may be formed by one aperture. Moreover, the second air outlet o2’ may be positioned on the handheld power tool 1 differently than as depicted in Fig. 1 and Fig. 2.

[0092] The third air outlet o3’ of the handheld power tool 1 is visible in Fig. 1. According to the illustrated embodiments, the second air outlet o2’ is formed by a slot-shaped aperture provided in an outer casing of the handheld power tool 1 located adjacent to the tool portion 30’ of the power tool 1.

[0093] However, according to further embodiments, the third air outlet o3’ of the handheld power tool 1 may be formed by another number of apertures which may have a different shape than a slot-shape. Moreover, according to further embodiments, the third air outlet o3’ of the handheld power tool 1 may be positioned on the handheld power tool 1 differently than as depicted in Fig. 1.

[0094] As is evident from the herein described, according to the illustrated embodiments, the fan housing 5 comprises an inlet 9 and three separate outlets o1, o2, o3. However, according to further embodiments, the fan housing 5 may comprise more than one inlet 9. Likewise, according to further embodiments, the fan housing 5 comprises more than three separate outlets o1, o2, o3. In other words, the fan housing 5 may comprise one or more additional outlets in addition to the three separate outlets o1, o2, o3 explained herein. Such one or more additional outlets may be a radial, a tangential, or an axial outlet, or a combination therebetween.

[0095] Furthermore, the handheld power tool 1 may comprise one or more additional air passages in addition to the three separate air passages p1, p2, p3 explained herein. Each of such one or more additional air passages may be connected to an additional outlet of the fan housing 5 according to the above. Moreover, each of such one or more additional air passages may be configured to cool an additional arrangement being separate from the first, the second, and the third arrangement a1, a2, a3 explained herein. Furthermore, each of such one or more additional air passages may be connected to one of the first, the second, or the third air outlets o1’, o2’, o3’ of the handheld power tool 1, or to a separate air outlet being distinct / separate from each of the first, the second, and the third air outlets oT, o2’, o3’ of the handheld power tool 1 explained herein.

[0096] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims. As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

CLAIMS1. A handheld power tool (1) comprising a motor (3) configured to power a tool of the handheld power tool (1), wherein the power tool (1) comprises a fan housing (5) and a fan unit (7), wherein the fan housing (5) comprises an inlet (9) and three separate outlets (o1 , o2, o3), wherein the fan unit (7) is arranged to rotate in the fan housing (5) during operation of the power tool (1) to generate an airflow from the inlet (9) into each of the three separate outlets (o1, o2, o3), wherein the power tool (1) further comprises three separate air passages (p1, p2, p3) each connected to one of the three separate outlets (o1 , o2, o3), and wherein each of the three separate air passages (p1, p2, p3) is configured to cool a respective arrangement (a1 , a2, a3) of the power tool (1).

2. The handheld power tool (1) according to claim 1 , wherein the motor (3) of the power tool (1) is an electric motor, and wherein a first air passage (p1) of the three separate air passages (p1, p2, p3) is configured to cool the motor (3).

3. The handheld power tool (1) according to claim 2, wherein the power tool (1) comprises a battery compartment (11) configured to accommodate a battery (13) for supplying electricity to the motor (3), and wherein a second air passage (p2) of the three separate air passages (p1, p2, p3) is configured to cool the battery compartment (11).

4. The handheld power tool (1) according to any one of the preceding claims, wherein the power tool (1) comprises a control arrangement (21), and wherein a third air passage (p3) of the three separate air passages (p1, p2, p3) is configured to cool the control arrangement (21).

5. The handheld power tool (1) according to claim 4, wherein the motor (3) of the power tool (1) is an electric motor, and wherein the control arrangement (21) comprises power electronics (23) configured to regulate the supply of electricity to the motor (3).

6. The handheld power tool (1) according to any one of the preceding claims, wherein the fan unit (7) is connected to an output shaft (3’) of the motor (3).

7. The handheld power tool (1) according to any one of the preceding claims, wherein the fan unit (7) is a radial fan unit.

8. The handheld power tool (1) according to any one of the preceding claims, wherein a first outlet (o1) of the three separate outlets (o1, o2, o3) forms an axial outlet.

9. The handheld power tool (1) according to claim 8, wherein the first outlet (o1) is formed by a number of apertures (15) provided in a wall (5’) of the fan housing (5).

10. The handheld power tool (1) according to claim 9, wherein the fan housing (5) comprises a number of air guide members (17) each arranged adjacent to one aperture (15) of the number of apertures (15), and wherein the number of air guide members (17) is arranged to divert the airflow through the first outlet (o1).

11. The handheld power tool (1) according to claim 9 or 10, wherein the fan unit (7) comprises a number of fan blades (8), and wherein the radial extension (r8) of the number of fan blades (8) is greater than a radial distance (r15) between a rotation axis (Ax) of the fan unit (7) and radially inner delimiting walls (15’) of the number of apertures (15).

12. The handheld power tool (1) according to any one of the claims 9 - 11, wherein the fan unit (7) comprises an axial end disc (10), and wherein the axial end disc (10) faces the wall (5’) of the fan housing (5).

13. The handheld power tool (1) according to claim 12, wherein the radial extension (r10) of the axial end disc (10) is smaller than a radial distance (r15) between a rotation axis (Ax) of the fan unit (7) and radially inner delimiting walls (15’) of the number of apertures (15).

14. The handheld power tool (1) according to any one of the claims 8 - 13, wherein the motor (3) of the power tool (1) is an electric motor, wherein the first outlet (o1) is connected to a first air passage (p1) of the three separate air passages (p1 , p2, p3), and wherein the first air passage (p1) is configured to cool the motor (3).

15. The handheld power tool (1) according to any one of the preceding claims, wherein a second outlet (o2) of the three separate outlets (o1 , o2, o3) forms a radial outlet, a tangential outlet, or a combination therebetween.

16. The handheld power tool (1) according to claim 15, wherein the power tool (1) comprises a battery compartment (11) configured to accommodate a battery (13) for supplying electricity to the motor (3), wherein the second outlet (o2) is connected to a second air passage (p2) of the three separate air passages (p1, p2, p3), and wherein the second air passage (p2) is configured to cool the battery compartment (11).

17. The handheld power tool (1) according to any one of the preceding claims, wherein a third outlet (o3) of the three separate outlets (o1, o2, o3) forms a radial outlet, a tangential outlet, or a combination therebetween.

18. The handheld power tool (1) according to claim 17, wherein the power tool (1) comprises a control arrangement (21), wherein the third outlet (o3) is connected to a third air passage (p3) of the three separate air passages (p1, p2, p3), and wherein the third air passage (p3) is configured to cool the control arrangement (21).

19. The handheld power tool (1) according to any one of the preceding claims, wherein the power tool (1) comprises three separate air outlets (oT, o2’, o3’) each configured to discharge air from one of the three separate air passages (p1 , p2, p3) to the surroundings.

20. The handheld power tool (1) according to any one of the preceding claims, wherein the power tool (1) is configured as one selected from the group consisting of: a chainsaw, a power cutter, a trimmer, a hedge trimmer, a combi-trimmer, and a leaf / debris blower.

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