Power tools with self-cleaning dust filters

Abstract

This invention relates to a handheld power tool having a housing and a drive unit including at least one waste heat component. The drive unit is arranged in a flow-isolated housing within the internal space of the handheld power tool. The flow-isolated housing has an internal space, and an external air delivery space is formed by arranging the flow-isolated housing within the housing of the power tool. The internal space and the external air delivery space are fluidly connected through a flow window having a dust filter. The handheld power tool has a cooling air delivery device arranged in the external air delivery space and establishing a coolant main flow for generating preferred turbulence along the external air delivery space. The filter surface of the dust filter is arranged tangentially to the flow direction of the coolant main flow, and a filtered coolant bypass for cooling at least one waste heat component can be diverted through the dust filter.

Description

Technical Field

[0001] Handheld grinding and polishing tools, such as straight grinders, belt grinders, tube grinders, fillet weld grinders, belt file grinders, or angle polishers, are used extensively not only in industry but also in handicrafts. All these power tools have in common that they generate dust during use, which is released through the abrasive process of grinding or polishing. This dust poses a risk because it can be drawn into the tool's interior along with the cooling airflow through the fan, causing damage there. Background Technology

[0002] If dust or other particles accumulate on sensitive components, it can cause premature wear or damage to components such as drive units or electronic devices, which can impair the appliance's lifespan and functional performance.

[0003] To avoid such damage, various protective measures have been developed over time. Common solutions include power tools with partially or fully enclosed drive units, ensuring protection of the drive unit. These structures are currently in use and help reduce dust ingress. However, the main drawback of this enclosed structure compared to open drive units is limited heat dissipation, which in turn reduces the appliance's effective power. Efficient heat exchange is crucial for frictionless operation, which presents a problem in the case of enclosed units.

[0004] In addition to the encapsulated drive unit, there are power tools equipped with an external dust filter at the motor unit. Such filters can be removed for cleaning in some cases, as described, for example, in patent document CN218397485U. While this type of dust filter provides some protection against dust ingress, it also has drawbacks. After a certain period of operation, fine grinding or polishing dust accumulates on the filter, which obstructs cooling airflow and reduces the cooling performance and effective power of the drive unit. Cleaning such filters is typically time-consuming and therefore often neglected in practice, which can impair the efficiency and durability of the power tool in the long run.

[0005] CN21617936U discloses an angle grinder that cleans air flowing into its housing through a deflector plate using a filter. The filter is arranged within a support structure, the receiving portion of which is subjected to different frequencies. During operation, the support structure, including the filter, oscillates together, and the filter is cleaned using the resonant frequency.

[0006] A handheld machine tool is known from EP 3 549 717, in which air entering the housing is divided into an external airflow flowing through the motor and an internal airflow. A separator disc is arranged in front of the motor, which, upon rotation, exerts a radially outward force on dirt particles contained in the cooling air. Thus, the dirt particles are guided into the external airflow and flow through the motor externally. A filter structure is arranged in the air inlet area to prevent dirt particles from entering the housing at all. Details regarding the cleaning of this filter structure are not available from published literature. Summary of the Invention

[0007] The purpose of this invention is to provide a maintenance-free handheld tool with improved user-friendliness.

[0008] This objective is achieved through the subject matter of independent claim 1. Preferred technical solutions and preferred improvements to the casing according to claim 1 can be derived from the dependent claims, the specification, and the drawings and their descriptions.

[0009] This invention relates to a handheld power tool, wherein "handheld power tool" should be understood as a portable device that can be operated by hand and is designed for various grinding or polishing tasks.

[0010] The handheld power tool described herein includes a drive unit. "Drive unit" should be understood as the core component of the handheld power tool, responsible for converting electrical energy into mechanical energy. The drive unit typically includes a motor and an electronic unit that generates the necessary power and controls and regulates the motor's functions. In this case, it may also include waste heat dissipation components, such as a cooler or fan, for dissipating heat generated during operation. The drive unit is crucial to the tool's effective power and helps ensure the tool's efficiency and durability.

[0011] Waste heat assemblies can comprise various elements or components that are subject to the removal of heat generated during operation. "Waste heat assembly" should be understood as a component within the drive unit of a handheld power tool that outputs heat during operation and therefore must be actively cooled. Typical waste heat assemblies consist of components that generate heat through energy conversion, such as motors and electronic units. These components require targeted cooling to prevent overheating and ensure optimal functionality and durability of the handheld power tool. Other components requiring cooling may also be included.

[0012] The drive unit is surrounded by a housing in the form of a flow-isolating housing and has an internal space within the housing. The flow-isolating housing is arranged within the power tool such that an external air supply space is formed between the inner side of the power tool's housing and the outer side of the flow-isolating housing.

[0013] The housing surrounding the flow isolation housing can itself be, in different embodiments, wholly or partially, surrounded by one or more other housings.

[0014] Alternatively, the flow isolation housing can be configured to surround only the waste heat components, with the drive unit located outside the flow isolation housing. Therefore, the "flow isolation housing" should be understood as a special housing within a handheld power tool, which, through its specific arrangement, creates an external airflow space. In addition to arranging other feasible components to be cooled, such as the drive unit, the internal space of the flow isolation housing can also be used. Thus, the flow isolation housing is used to control and isolate the flow within the power tool to enable targeted cooling of the waste heat components.

[0015] The flow mentioned above can include any type of fluid, especially gaseous fluids such as air or air mixtures, which can also be referred to as coolants in the following text.

[0016] The internal space of the flow isolation housing and the external air supply space are fluidly connected to each other through flow windows. The cooling air isolation caused by the flow isolation housing ensures that only filtered air enters the internal space of the housing and prevents dust and other contaminants from entering the sensitive components of the drive unit.

[0017] Therefore, the "flow window" should be understood as an opening in the flow isolation housing that connects the interior space of the housing to the external air supply space. The flow window is equipped with a dust filter to prevent dust and particles (depending on their size) from entering the interior space of the housing. This flow window allows a targeted bypass of filtered cooling air into the interior space for efficient cooling of waste heat components, while guiding the main airflow along the external air supply space.

[0018] "Dust filter" should be understood as a filter element arranged in a flow window within the flow isolation housing of a handheld power tool. The dust filter prevents abrasive particles and contaminants from entering the housing's interior space from the external airflow space, while allowing a filtered bypass of the cooling airflow to pass through. The dust filter is positioned such that its filter surface is tangential to the direction of the mainstream coolant flow. This ensures that particles are efficiently trapped and do not accumulate at the filter, but are instead carried away by the mainstream coolant, resulting in a longer filter life and consistent cooling performance.

[0019] The handheld power tool further includes a cooling air delivery device arranged in the external air delivery space of the power tool and configured to generate a coolant mainstream that flows around the flow isolation housing and serves to externally cool the flow isolation housing and simultaneously remove dust. Therefore, "cooling air delivery device" should be understood as a component in the external air delivery space of the handheld power tool configured to generate an airflow and selectively guide this airflow along the external air delivery space through the tool's internal space. This device can be implemented as a fan, blower, or other air-delivering element. The device generates a coolant mainstream, which is preferably turbulent and flows around the flow isolation housing.

[0020] A filtered coolant bypass can be diverted from the preferred turbulent coolant main stream. This bypass coolant enters the internal space of the housing through a flow window, where it is specifically used to cool waste heat components. This ensures efficient cooling while the internal space of the housing remains protected from dust and particles. Here, the filter surface of the dust filter is designed to efficiently filter the main coolant stream.

[0021] Preferably, the handheld power tool further includes a pump assembly, which is at least partially disposed within the housing interior space. The pump assembly and the pump configuration are designed to generate a low pressure within the housing interior space relative to the housing exterior space, so as to draw in filtered coolant bypass flow diverted from the coolant mainstream through a flow window in a filtered manner, transverse to the flow direction of the coolant mainstream.

[0022] Here, "pump assembly" should be understood as a low-pressure generating component, preferably arranged within the housing of the handheld power tool. The pump is preferably positioned such that it generates a lower pressure within the housing compared to the external air delivery space. This lower pressure is used to draw in filtered coolant bypass flow diverted from the main coolant flow through a flow window, transverse to the flow direction of the main coolant flow. The pump thus supports targeted flow of coolant through the internal space, enabling efficient cooling of waste heat components within the housing.

[0023] Preferably, the handheld power tool also has a drive shaft, and a cooling air delivery device is coupled to the drive shaft.

[0024] The term "drive shaft" should be understood as a rotating element that is a component of the cooling air delivery system of a handheld power tool. The drive shaft is designed to be coupled to the cooling air delivery system, which generates a main stream of coolant and actively guides it along the external air delivery space. The rotation of the drive shaft generates a turbulent main stream of coolant, which, due to the diversion of filtered coolant bypass, contributes to the efficient cooling of waste heat components. The coupling of the drive shaft to the cooling air delivery system enables synchronized and efficient airflow that supports constant and targeted cooling of the drive unit.

[0025] The pump assembly or pump is preferably a rotatable, closed, especially disc-shaped or columnar component with a conveying structure arranged in a columnar opening of a flow isolation housing, particularly an engagement disc having a helical recess on the outer side of the engagement disc extending in the circumferential direction.

[0026] Preferably, the pump assembly has a helical recess at the cylindrical periphery. Preferably, the pump assembly is coupled to and driven by the rotor of the drive shaft.

[0027] The term "spiral recess" should be understood as a special structure arranged around the periphery of a column. This recess is designed in a spiral or helical shape and helps optimize airflow or coolant flow within the flow isolation housing. The spiral recess enables controlled airflow delivery and targeted guidance.

[0028] Because the pump is preferably coupled to the drive shaft, the spiral recess actively participates in the rotational motion of the drive shaft. This coupling generates a low pressure that draws in filtered coolant bypass, thereby cooling the waste heat components inside the power tool's housing, which contributes to the tool's optimal performance and durability.

[0029] Preferably, the pump assembly has a left-hand threaded groove with a pitch in the range of 1.5 mm to 3.5 mm, preferably in the range of 2.0 mm to 2.5 mm.

[0030] Preferably, there is a gap between the outer diameter of the columnar periphery of the pump assembly and the inner diameter of the internal space of the housing in the region of the pump assembly, the gap preferably being in the range of 0.2 mm to 1.0 mm, and particularly preferably in the range of 0.4 mm to 0.6 mm.

[0031] The flow isolation housing preferably has a motor cover, and the flow window is arranged on the circumferential surface of the motor cover.

[0032] "Motor cover" should be understood as a protective device that at least partially covers the movable isolation housing of a handheld power tool and, in particular, protects the motor of the drive unit. The motor cover protects the motor from external influences such as dust, dirt, and mechanical damage, thereby promoting the motor's durability and functionality.

[0033] The motor cover has at least one flow window disposed on its circumferential surface. This flow window enables fluid connection between the internal space of the housing and the external air supply space. Through the flow window, airflow can pass from the external air supply space into the internal space of the housing. By arranging the flow window on the motor cover, filtered coolant bypass flow is efficiently guided through the motor cover, enabling targeted cooling of the motor while minimizing the ingress of dust and contaminants into the internal space of the flow-isolated housing. This contributes to efficient cooling and optimal performance of the handheld power tool. In different embodiments, the flow window may also be disposed on the circumferential surface of the flow-isolated housing.

[0034] Preferably, the flow window is a plurality of flow windows, wherein the plurality of flow windows are preferably arranged at equal intervals.

[0035] "Multiple flow windows" should be understood as multiple openings in the flow isolation housing and / or motor cover that enable fluid connection between the internal space of the housing and the external air supply space. The multiple flow windows are preferably arranged such that they are equidistant from each other, meaning they have a uniform spacing relative to each other.

[0036] The arrangement of multiple flow windows promotes improved airflow and enables uniform distribution of filtered coolant bypass within the flow isolation housing. This allows for more efficient cooling of waste heat components and improves the performance of handheld power tools. Furthermore, the equidistant arrangement ensures uniform ventilation and cooling of all areas of the motor or drive unit, further enhancing cooling efficiency and minimizing the risk of overheating.

[0037] Preferably, the dust filter and / or pump has at least one of the following materials: metal, sintered metal, ceramic, sintered ceramic, polymer, non-magnetic material or stainless steel.

[0038] Therefore, dust filters and pumps can be constructed from a variety of materials to ensure optimal performance and durability. This includes metals, which are frequently used due to their high strength and stability, as well as their ability to withstand high temperatures. One particular form is sintered metal, produced through a sintering process. This sintered metal provides a porous structure that enables efficient filtration and improved airflow, thereby enhancing the efficiency of the dust filter.

[0039] Ceramics are another important material, produced by heating and cooling inorganic components. They are hard, wear-resistant, and offer high thermal stability, making them ideal for applications with high heat loads. Similarly, sintered ceramics, also made through sintering and additionally chemically stable, are suitable for use in dusty and humid environments.

[0040] Polymers offer a cost-effective and flexible alternative due to their lightweight and chemical stability. The versatility of polymers allows them to be processed into various shapes, making them ideal for sealing and flexible applications. Complementing this is the use of non-magnetic materials to ensure that the performance of power tools is unaffected by electromagnetic interference. This contributes to the reliability and stability of the tools.

[0041] Stainless steel offers high corrosion resistance and robustness. With at least 10.5% chromium, it provides excellent rust protection and is therefore particularly suitable for use in demanding environments. The use of these materials in dust filters and pumps significantly improves the efficiency and durability of handheld power tools.

[0042] The dust filter is preferably implemented as a filter cloth.

[0043] Here, "filter cloth" should be understood as a special, permeable fabric designed to filter dust and other particles. The fabric is composed of fibers arranged in such a way that it provides a large surface area that can trap particles from air or coolant flow while simultaneously allowing air or liquid to flow through.

[0044] Using filter cloth as a dust filter offers several advantages. First, the outstanding feature of filter cloth is its flexibility and adaptability, which allows for easy integration into the design of power tools. Furthermore, filter cloth can be manufactured in different densities and material combinations to meet specific filtration requirements, ensuring high adaptability to various usage conditions. Another advantage is its good air permeability, which promotes efficient airflow and simultaneously enables efficient dust filtration.

[0045] The dust filter is preferably implemented as a screen and / or a screen plate.

[0046] "Sieve" should be understood as a finely meshed material made of interwoven threads or filaments used to filter dust and other particles. This fabric is able to block small particles while allowing air or liquid to flow through the mesh.

[0047] "Sieve plate" should be understood as a flat metal plate with multiple holes to perform a function similar to a sieve. Alternatively, the sieve plate can be formed using a metal mesh or a plate with gill-like openings. The sieve plate can have openings of different shapes, sizes, and protrusions, selected according to the specific filtration requirements.

[0048] Using screens and / or screen plates as dust filters offers several advantages. First, screens can efficiently separate dust and other unwanted particles while maintaining airflow or fluid flow. Second, both screens and screen plates are extremely robust and durable. Furthermore, the structure of the screen allows for high flow rates, which benefits the efficiency of cooling processes in power tools and reduces the risk of overheating.

[0049] The dust filter is preferably manufactured as a gap filter made of wound metal wire.

[0050] "Gap filter" should be understood as a special type of filter constructed from wound metal wire. This type of filter is designed so that air or coolant passes through the narrow gaps or spaces formed by the wound wire, while simultaneously blocking larger particles such as dust and dirt. The structure of a gap filter enables the efficient separation of unwanted particles and contaminants.

[0051] Using interstitial filters made of wound metal wire as dust filters offers several advantages. First, the high strength and durability of metal wire ensure a long filter lifespan, even under harsh operating conditions. Second, the wound structure ensures an increased filter surface area, improving dust separation efficiency without restricting air or liquid flow. Furthermore, metal wire can be configured in various cross-sectional shapes (circular, trapezoidal, rectangular, square, with and without edges), allowing for the creation of interstitial filters that meet desired requirements. Therefore, using interstitial filters helps optimize the performance of handheld power tools by minimizing dust and contaminant buildup and maintaining efficient coolant flow.

[0052] Dust filters are preferably calendered at the surface.

[0053] "Calendar dust filters" should be understood as filter materials (filter cloth, filter fabric) processed through a calendering process, in which the filter material is guided through two rotating rollers. This process compresses and smooths the surface structure of the filter, thereby making the porous structure and mesh of the material more uniform and controlled. This improves the filter's filtration characteristics by optimizing the permeability to air or coolant while maximizing the retention of dust and other particles.

[0054] Using calendered dust filters offers several advantages. First, the calendering process improves the filter's structural integrity, resulting in a longer service life and greater resistance to mechanical loads. Second, calendered filters achieve a more uniform filtration effect, meaning they can trap particles more efficiently without significantly impeding airflow or liquid flow. Furthermore, the smooth surface of calendered filters makes cleaning easier, as less dirt and deposits accumulate. This contributes to improved efficiency in the cooling process. Overall, calendered dust filters significantly improve the performance of power tools by minimizing dust accumulation and ensuring optimal airflow or coolant flow.

[0055] Handheld power tools preferably have a cooling air inlet and a cooling air outlet.

[0056] "Cooling air inlet" should be understood as a specially designed opening or channel in a handheld power tool through which air or coolant can enter the tool.

[0057] "Cooling air outlet" should be understood as an additional opening or passage that allows heated airflow to exit the power tool. These two openings, the inlet and the outlet, are shaped and arranged such that they facilitate the guidance of turbulent airflow and maximize the delivery or dissipation of cooling air.

[0058] The cooling air inlet and outlet are integrated into the handheld power tool, enabling continuous airflow that helps keep the drive unit temperature low and prevents overheating. This is particularly important because excessively high temperatures can impair tool performance and lead to tool failure.

[0059] Furthermore, the combination of cooling air inlet and cooling air outlet improves the efficiency of the cooling system by providing targeted airflow that efficiently removes waste heat. This not only results in better performance of the power tool but also contributes to the durability of the drive unit.

[0060] Furthermore, the cooling air outlet allows dust and other particles generated during operation to be expelled, minimizing the accumulation of dirt inside the tool. Therefore, these structural features are crucial for optimal functionality and ease of maintenance of handheld power tools.

[0061] Preferably, the turbulent flow of the coolant mainstream and the resulting shear force cause the dust filter to self-clean.

[0062] "Turbulent flow" should be understood as the design of the coolant flow channel in a handheld power tool, resulting in chaotic and irregular movement within the channel, rather than a stratified flow. This turbulent flow causes air particles within the coolant flow channel to move in different directions, which improves the efficiency of heat transfer and ensures more uniform cooling of the drive unit. Turbulent processes are common in airflow. Turbulent flow occurs at high Reynolds numbers, which are typical for most practical applications involving air, such as the cooling air in power tools.

[0063] Furthermore, turbulent flow generates shear forces within the coolant mainstream. These forces are generated by the varying velocities and directions of motion of air particles in the airflow. This shear force acts directly on the surface of the dust filter, causing accumulated dust and contaminants to detach from the filter surface and be guided back into the coolant mainstream, rather than depositing on the filter surface.

[0064] The turbulent flow that generates shear forces offers several advantages to dust filters. First, it reduces the need for frequent manual cleaning of the filter, as the shear forces ensure less or almost no dust and deposit buildup. This results in a longer filter lifespan and lower maintenance costs.

[0065] Secondly, this self-cleaning property improves the overall efficiency of the cooling system. A cleaner dust filter ensures that the coolant bypass can flow unimpeded, thereby optimizing cooling performance and reducing the risk of overheating of the drive unit.

[0066] Overall, turbulent flow and the resulting shear forces significantly contribute to the functionality and durability of handheld power tools by ensuring efficient cooling and continuous self-cleaning of the dust filter.

[0067] Preferably, at least one waste heat component includes at least one or a portion of the following components: a drive unit, a motor unit, and an electronic device unit.

[0068] Therefore, this invention ensures efficient cooling of waste heat components through targeted airflow, thereby preventing overheating and improving the performance and lifespan of power tools. Here, the dust filter's design, flowing transversely to the mainstream coolant flow, minimizes the accumulation of dust and contaminants inside the tool, reducing the need for frequent cleaning. Furthermore, a self-cleaning mechanism induced by turbulent flow enables continuous dust removal, thereby reducing maintenance costs. In addition, robust materials such as metals, sintered metals, and stainless steel ensure a long component lifespan even under particularly demanding operating conditions. Finally, minimizing dust accumulation and efficient cooling improve the overall performance of the power tool.

[0069] Overall, this invention demonstrates significant improvements in the design and functionality of handheld power tools by combining efficient cooling with efficient dust control, which results in greater reliability and user satisfaction. Attached Figure Description

[0070] Further preferred designs of the handheld power tool according to the invention are derived from the embodiments described below with reference to the accompanying drawings and the drawings themselves. The drawings show: Figure 1 A cross-section of a handheld power tool according to an embodiment of the present invention is shown. Figure 2 It shows that according to Figure 1 A cross-section of a portion of the power tool, through which the flow-isolating housing can be seen. Figure 3 A perspective view shows the flow isolation housing 4, which is the core component of the handheld power tool 1. Figure 4 It shows Figure 1 A perspective view of the motor cover of a handheld power tool. Figure 5 It shows Figure 1 A three-dimensional view of a handheld power tool with a pump in the form of a meshing disc, and Figure 6 It shows the method for generating Figure 1 The filtration principle of the filtered coolant bypass in handheld power tools. Detailed Implementation

[0071] Figure 1 A handheld power tool 1 is shown, which is particularly designed for grinding and polishing work, for example, in the case of an angle grinder, straight grinder, belt grinder, tube grinder, fillet weld grinder, belt file grinder or angle polisher.

[0072] This power tool 1 includes a central drive unit 2, which has a motor unit and an electronics unit (not shown) and puts a drive shaft 14 into rotational motion. Adjacent to the drive unit 2 is a pump 11 and a cooling air delivery device 8. The pump 11 and the cooling air delivery device 8 are connected to the drive shaft 14 and rotate together with it in the same direction. An output shaft is arranged at an angle of approximately 90° relative to the drive shaft 14. An angular transmission mechanism 19 exists between the drive shaft 14 and the output shaft 18, which converts the drive motion arranged along the longitudinal direction of the power tool into an output motion arranged transversely to the longitudinal direction. A tool (not shown) is arranged at the output shaft 18.

[0073] Figure 2 A partial area of ​​the power tool 1 is shown, from which a perspective view of the flow isolation housing 4 can be seen. The flow isolation housing 4 is arranged within the housing 20 of the power tool 1. The flow isolation housing 4 contains a drive unit 2, which has at least one waste heat component 3, here a motor unit. The motor unit generates heat during operation, which must be cooled to maintain the tool's lifespan and effective power.

[0074] The flow isolation housing 4, which is the drive unit housing 4, is located within the housing 20 of the power tool 1. An internal space 5 is formed between the inner side of the housing 20 and the outer side of the flow isolation housing 4. In other words, the outer side of the flow isolation housing 4 is spaced apart from the inner side of the housing 20 of the power tool 1. Based on this arrangement, the internal space 5, or external air delivery space 13, is formed. The flow isolation housing 4 is designed such that it has an internal housing space 12, which is fluidly connected to the external air delivery space 13 through a flow window 6. This flow window 6 is equipped with a dust filter 7, which prevents abrasive particles generated during operation from entering the internal housing space 12. The dust filter 7 protects the motor unit from wear and thus ensures an extended service life and reliability of the power tool 1.

[0075] To optimally cool the power tool 1, a cooling air delivery device 8 is installed in the external air delivery space 13, which generates a cooling airflow. This cooling air delivery device 8 ensures a mainstream of coolant 9 along the turbulent flow of the external air delivery space 13.

[0076] Here, the filter surface of the dust filter 7 is arranged tangentially to the flow direction of the coolant mainstream 9, thereby directly blowing away dust particles from the filter 7, where self-cleaning is supported. This tangential arrangement of the filter surface of the dust filter 7 relative to the flow direction of the coolant mainstream 9 ensures efficient filtration and reduces the risk of clogging due to dust particles. Targeted guidance of the coolant mainstream 9 through flow control helps maintain the dust filter's high efficiency over a long period.

[0077] Here, a portion of the airflow from the main coolant stream 9, namely the filtered coolant bypass 10, is diverted into the internal space 12 of the housing to specifically cool the waste heat components 3 there. This enables controlled temperature regulation and prevents the motor from overheating. It also prevents dust from potentially entering the sensitive areas of the drive unit 2.

[0078] In the illustrated embodiment, the power tool 1 also includes a pump assembly (also referred to as a pump) 11, which is constructed within the housing interior space 12. The pump 11 generates a low pressure within the housing to draw in filtered coolant bypass 10. The filtered bypass 10 is drawn in through flow window 6, transverse to the main flow direction 9, further improving cooling efficiency.

[0079] The drive shaft 14 of the power tool 1 is coupled to the cooling air delivery device 8. This coupling enables efficient control of airflow and actively supports the removal of excess heat. To induce air delivery, the pump 11, also connected to the drive shaft 14, has a spiral recess at its cylindrical periphery. This structure, with its given shape at the periphery, facilitates the extraction of airflow from the internal space 12 of the flow isolation housing 4. The combination of the cooling air delivery device 8 and the pump 11 creates a suction effect when they are in rotational motion. As a result, a portion of the coolant main stream 9 is diverted and enters the internal space 12 of the flow isolation housing 4 through the flow window 8 and the dust filter 7. This portion, i.e., the filtered coolant bypass 10, efficiently cools the drive unit 2.

[0080] To efficiently control airflow and achieve uniform cooling distribution, the flow isolation housing 4 is equipped with a motor cover 15, in which the flow window 6 is positioned on the circumferential surface of the motor cover 15. Furthermore, the flow window 6 is implemented as a plurality of equally spaced openings. This arrangement supports uniform airflow distribution and facilitates the self-cleaning of the filter 7, as turbulent flow and the resulting shear force are reduced, and ideally, dust accumulation on the filter 7 is prevented. Additionally, the handheld power tool 1 has a cooling air inlet 21 and a cooling air outlet 22. Air can enter and exit the power tool 1 through these cooling air inlets and outlets. These openings are strategically positioned to ensure efficient airflow guidance for cooling and to remove waste heat from the drive unit 2.

[0081] The combination of these components results in a durable power tool 1 with increased effective power, which is protected from damage caused by abrasive dust and ensures efficient cooling of critical components.

[0082] Figure 3 A perspective view shows the flow isolation housing 4, a core component of the handheld power tool 1, which surrounds and protects the drive unit 2, particularly the motor unit. The closed external shape of the flow isolation housing 4 creates a clear separation between the internal space 12 of the housing and the external air delivery space 13, in which the sensitive components of the drive unit 2 are located, and where the filtered coolant bypass 10 can be diverted into the internal space via the flow window 6, while the turbulent coolant main flow 9 flows through the external air delivery space.

[0083] The flow isolation housing 4 is designed such that it fluidly connects the internal space 12 of the housing to the external air delivery space 13 through a flow window 6 with an integrated dust filter 7. The flow window 6 is strategically arranged so that the filtered coolant bypass 10 can be directed into the internal space 12 of the housing. Here, the internal space 12 is thus largely kept free of dust particles, while the coolant bypass 10 gains a passage to the waste heat components to ensure cooling of the waste heat components.

[0084] In summary, the flow-through housing 4 serves as a protective and steering structure, enabling efficient cooling of the drive unit while simultaneously preventing abrasive particles from entering sensitive components. This improves the durability and reliability of the power tool 1 through an enclosed yet well-ventilated system.

[0085] Figure 4The motor cover 15 is shown as an integral component of the flow isolation housing 4. This motor cover contributes to the stability and reliability of the drive unit 2 by protecting the drive unit from external influences such as dust, dirt, and other contaminants.

[0086] The motor cover 15 is designed with multiple equidistant flow windows 6 on its circumferential surface. These flow windows 6 allow for the controlled passage of a coolant bypass 10, which, before flowing into the housing interior space 12, is diverted from the main coolant stream 9 by a flow isolation housing 4 equipped with a pump 11 and a cooling air delivery device 8 disposed at the pump, and is cleaned by a dust filter 7. In this arrangement, the motor cover 15 actively supports air guidance and ensures that only filtered air reaches the vicinity of the waste heat assembly 3.

[0087] Overall, the motor cover 15 serves the dual function of protecting the waste heat assembly 3 and supporting its efficient cooling, which contributes to the improved power efficiency and durability of the power tool 1.

[0088] Figure 5 A pump assembly 11 is shown, which in the illustrated embodiment is designed as an engaging disc 11 with a helical recess at its cylindrical periphery and directly coupled to the drive shaft 14 of the handheld power tool 1. This configuration ensures efficient air delivery and low-pressure generation for targeted intake of coolant bypass 10. A continuous low pressure is generated within the housing interior space 12 along the helical recess of the engaging disc, acting relative to the external air delivery space 13.

[0089] This low pressure facilitates the intake of filtered coolant bypass 10 transverse to the flow direction of the main coolant stream 9, by guiding air through the flow window 6 and the dust filter 7 installed at the flow window. The concave spiral design ensures targeted and uniform flow, which ensures constant cooling of the waste heat assembly 3 of the drive unit 2.

[0090] The specially shaped engagement disc 11 generates a constant low pressure within the flow isolation housing 4, thereby ensuring reliable separation of the coolant bypass 10 from the main coolant flow 9. The cleaned coolant bypass 10, obtained through a dust filter, allows for cleaner and more controlled cooling of sensitive motor components.

[0091] Figure 6The filtration principle of the hand-held power tool 1 is shown. The main coolant flow 9 flows tangentially past the dust filter 7 at high speed and in a turbulent motion. By this arrangement, large particles in the main coolant flow 9 are guided along the surface of the dust filter 7, such that these large particles flow in the direction of the cooling air outlet 22 within the external air conveyance space 13 and do not enter the housing interior space 12.

[0092] The filtered coolant bypass flow 10 is diverted by the low pressure (p2 < p1) present in the housing interior space 12, and this coolant bypass flow is purposefully drawn in to cool the waste heat component 3.

[0093] The turbulent flow of the main flow 9 ensures that the particles do not adhere to the filter surface but are continuously carried away together. Thus, the filtering function always remains active without restriction, which significantly improves the service life and performance of the dust filter 7 and thereby improves the service life and performance of the power tool 1.

[0094] List of reference numerals: 1 Power tool 2 Drive unit [[ID=I5]]3 Waste heat component 4 Flow isolation housing 5 Interior space of the power tool 6 Flow window 7 Dust filter 8 Cooling air conveyance device 9 Main coolant flow 10 Filtered coolant bypass flow 11 Pump, engagement disk (Kammscheibe) 12 Housing interior space 13 External air conveyance space 14 Drive shaft 15 Motor cover 16 Particle 18 Output shaft 19 Angular transmission mechanism 20 Housing of the power tool 1 21 Cooling air inlet 22 Cooling air outlet

Claims

1. A handheld power tool (1), particularly an angle grinder, straight grinder, belt grinder, tube grinder, fillet weld grinder, belt file grinder, or angle polisher, The hand-held power tool has a housing (20), a drive unit (2), preferably a motor unit, and an electronics unit (3), the drive unit comprising at least one waste heat component (3), wherein The drive unit (2) is arranged in the fluid isolation housing (4) within the internal space (5) of the handheld power tool (1). The flow isolation housing (4) has an internal space (12), and an external air delivery space (13) is formed by arranging the flow isolation housing (4) in the housing (20) of the power tool (1), wherein the internal space (12) and the external air delivery space (13) are fluidly connected by a flow window (6) having a dust filter (7). The handheld power tool has a cooling air delivery device (8) arranged in the external air delivery space (13) and provides a coolant main stream (9) for generating preferred turbulence along the external air delivery space (13). The dust filter (7) has its filter surface arranged tangentially relative to the flow direction of the coolant mainstream (9), and The dust filter (7) can divert filtered coolant bypass (10) for cooling at least one waste heat component (3).

2. The hand-held power tool (1) as claimed in claim 1, characterized in that The handheld power tool (1) further includes a pump device (11) which is at least partially arranged in the internal space (12) of the housing and is configured to generate a low pressure in the internal space (12) of the housing relative to the external air delivery space (13) so as to draw in filtered coolant bypass (13) diverted from the main coolant flow (9) through the flow window (6) in a direction transverse to the flow direction of the main coolant flow (9).

3. The handheld power tool (1) according to claim 1, characterized in that, The handheld power tool (1) also has a drive shaft (14), and the cooling air delivery device (8) is coupled to the drive shaft (14).

4. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The pump assembly (11) has a spiral recess at the columnar periphery and is coupled to the drive shaft (14).

5. The handheld power tool (1) according to claim 3, characterized in that, The pump assembly (11) has a left-hand threaded groove with a pitch ranging from 1.5 mm to 3.5 mm, preferably from 2.0 mm to 2.5 mm.

6. The handheld power tool (1) according to claim 3 or 4, characterized in that, The power tool (1) has a gap between the outer diameter of the columnar periphery of the pump assembly (11) and the inner diameter of the housing interior space (12) in the region of the pump assembly (11), the gap preferably being in the range of 0.2 mm to 1.0 mm, and particularly preferably in the range of 0.4 mm to 0.6 mm.

7. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The flow isolation housing (4) has a motor cover (15), and the flow window (6) is arranged on the circumferential surface of the motor cover (15).

8. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The flow window (6) is a plurality of flow windows, wherein the plurality of flow windows are preferably arranged at equal intervals.

9. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The dust filter (7) and / or the pump device (11) have at least one of the following materials: metal, sintered metal, ceramic, sintered ceramic, polymer, non-magnetic material, stainless steel.

10. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The dust filter (7): a) Implemented as filter cloth; b) Implemented as a screen and / or screen plate; c) Manufactured as a gap filter made of wound metal wire; or d) Calendering at the surface.

11. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The handheld power tool (1) has a cooling air inlet (22) and a cooling air outlet (21).

12. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The turbulent flow and shear force generated by the mainstream coolant (9) cause the dust filter (7) to self-clean.

13. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The at least one waste heat component (3) includes at least one or a portion of the following components: a drive unit, a motor unit, and an electronic device unit.

14. The handheld power tool (1) according to any one of the preceding claims, characterized in that, The fluid isolation housing (4) is a drive unit housing, a motor unit housing, and / or an electronic device unit housing.

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