Device, system, and method for cooling a tool

Abstract

The invention relates to a device for cooling a tool, which device comprises a main body, a contact element, and at least one inlet into the main body and an outlet out of the main body, wherein the inlet and the outlet are interconnected by one or more inner channel(s) in the main body, and the device can be connected to the tool in such a way that the contact element is in contact with the tool, and the one or more inner channel(s) is / are designed to conduct a cooling fluid. One or more inner channels comprise(s) a contact portion, the contact portion being in contact with the contact element, and the contact portion comprising multiple flow-guiding elements which are designed in such a way that they locally increase the turbulence and the flow rate of the cooling fluid through the contact portion. The invention also relates to a system comprising the device and the tool, and to a cooling method using the system.

Description

[0001] DEVICE, SYSTEM AND METHOD FOR COOLING A TOOL

[0002] DESCRIPTION

[0003] The invention relates to a device for cooling a tool, wherein the device comprises a base body, a contact element and at least one inlet into the base body and one outlet from the base body, wherein the inlet and the outlet are connected to one another by one or more internal channels in the base body and the device is connectable to the tool such that the contact element is in contact with the tool, and the one or more internal channels are configured to conduct a cooling liquid. One or more internal channels comprise a contact section, wherein the contact section is in contact with the contact element, wherein the contact section comprises a plurality of flow guide elements that are configured to locally increase the turbulence and the flow velocity of the cooling liquid through the contact section.Furthermore, the invention relates to a system comprising the device and the tool as well as a cooling method using the system.

[0004] Background and state of the art

[0005] The invention relates to the field of industrial manufacturing, in particular turning for machining workpieces by means of a tool.

[0006] In industrial manufacturing processes, such as turning, effective cooling strategies are crucial to reduce the heat generated between the tool and workpiece during chip formation. Flood cooling, using cutting fluids, is the most commonly used method in metalworking to date. The cutting fluid is applied at flow rates of several hundred liters per hour to cool the tool or workpiece and is applied through external nozzles as close as possible to the cutting zone between the tool and workpiece. If these conditions are not met during turning, the cooling lubricant effect is insufficient. Furthermore, the use of large quantities of cutting fluid, its limited service life, and the associated high maintenance and disposal costs place considerable economic and health risks on companies.

[0007] In recent years, special cooling strategies such as minimum quantity lubrication and cryogenic cooling have been developed to reduce the use of cooling lubricants while ensuring efficient cooling. All processes are continuously being developed to ensure the most sustainable production possible. However, they still have some inherent disadvantages, such as high energy and resource consumption and the costly disposal of operating materials. Therefore, research and development are increasingly focusing on innovative approaches to improving cooling in industrial manufacturing processes to enable the most sustainable production possible.To counteract the disadvantages of inadequate process control and non-reproducible performance, innovative cooling strategies can be used. These are based on a closed circuit, so that no external cooling lubricant is introduced into the machining zone. Thus, all the heat generated during machining is dissipated, on the one hand, by the chip and, on the other hand, by the closed internal cooling system. Heat transfer for internal cooling occurs indirectly through conduction and forced convection, with the cooling fluid achieving targeted and uniform cooling of the tool, leading to improved temperature control and increased process stability. Furthermore, internal cooling significantly reduces the need for cooling lubricants and thus minimizes the associated storage and disposal costs.

[0008] Processes and systems that enable the use of closed circuits for internal cooling are already known. The following state of the art has now developed in this field:

[0009] DE19730539C1 describes a heat sink within a modified tool holder. It features segmented, plate-shaped microstructures with channels smaller than 300 pm to increase cooling efficiency. Heat transfer occurs through a highly thermally conductive material on the underside of the tool. The described heat sink can be arranged on two opposite sides.

[0010] WO2018046489A1 describes a modified tool holder that enables improved cooling and temperature control of the cutting element. The tool comprises a cutting insert and a cooling device. The cooling device consists of a double pipe that allows both the supply and removal of the cooling fluid. The coolant is directed to the underside of the tool through this double pipe.

[0011] SU795883A1 describes a tool holder or turning tool with internal cooling. It has a housing with an axial channel. This channel is connected to a tube made of heat-conducting material and partially filled with a coolant, e.g., water. Evaporation of the coolant dissipates heat from the cutting insert and transfers it to a distant, cooler area. The tube is hinged to the internal chamber and can be adjusted to various angles to enable cooling at any position of the tool holder or turning tool.

[0012] The techniques described so far require either an adaptation of the tool or the tool holder, which, due to standardized interfaces and geometries, are not suitable for industrial use. Furthermore, no investigations into cooling performance with regard to flow parameters and heat transfer mechanisms have been conducted. Based on the state of the art, there is therefore a need for a novel cooling strategy that is industrially applicable, transports heat more efficiently from the tool, and increases the energy efficiency of the tool system without requiring modification of the tool or the tool holder. Object of the invention

[0013] The object of the invention is to provide a technical solution for cooling a tool that avoids the release of toxic or irritating cooling fluids into the environment and reduces the consumables required for cooling. Furthermore, the object of the invention is to provide an economical solution for cooling the tool that ensures high and reproducible cooling performance and in which a cooling fluid can be brought particularly close to the heat-dissipating contact surface between the tool and the workpiece.

[0014] Summary of the invention

[0015] The object is achieved by the features of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0016] In a first aspect, the invention relates to a device for cooling a tool, wherein the device comprises a base body, a contact element and at least one inlet into the base body and one outlet from the base body. The inlet and the outlet are connected to each other by one or more internal channels in the base body. The device is connectable to the tool such that the contact element is in contact with the tool. The one or more internal channels are configured to conduct a cooling liquid. The one or more internal channels comprise a contact section, wherein the contact section is in contact with the contact element to enable heat transfer.The contact section comprises a plurality of flow guide elements that are configured to change the flow velocity and locally increase the turbulence of the cooling fluid through the contact section, which in turn leads to an increase in heat transfer from the contact element.

[0017] A coolant can be continuously fed through the fixture through the internal channels in the base body of the fixture. This allows the coolant to be kept in a closed circuit for cooling the fixture and the associated tool, preventing it from being released uncontrollably into the environment. Furthermore, a closed circuit, through which an environmentally friendly coolant flows, is preferably used, eliminating the need to introduce external coolant into the machining zone. Consequently, the health and safety risks associated with traditional flood cooling can be completely eliminated from the cooling process. Workers are not exposed to the coolant, and there is no risk of it escaping and contaminating workpiece and machine surfaces. At the same time, the consumables required for cooling are reduced.Since the inner channels can be connected to a peripheral system to form a closed fluid circuit, significantly smaller quantities of coolant (e.g., compared to flood cooling) can be used over a longer period of time before it needs to be replaced. This is particularly economical and environmentally friendly. Since the device according to the invention can be connected to the tool, it is also possible to bring the coolant flowing in the inner channels particularly close to the tool. In particular, the coolant can thus be brought extremely close to the contact area between the tool and a workpiece to be machined. Since this is the area where the most heat is released, the cooling process is significantly more efficient due to this close contact.This is particularly advantageous compared to flood cooling systems, where the coolant usually cannot reach this area or evaporates into the environment before reaching this area.

[0018] A further advantage of the invention is that the device for cooling the tool is a part independent of the tool itself. Although the device according to the invention can be connected to the tool, the tool does not necessarily have to be a component of the device according to the invention. Therefore, the device can be used directly with any suitable tool without the tool having to be modified. The fact that the tool does not have to be modified to attach the device can mean, in particular, that modifications to the tool are not absolutely necessary. This means that, advantageously, no adaptation of known or proven machining processes is necessary through the use of new tools. Furthermore, the strength of the tool is advantageously not negatively affected because no channels need to run inside the tool.Furthermore, it is not necessary to interrupt the coolant circuit when replacing the tool, which advantageously prevents contamination or leaks. Since the tool is usually a consumable part that is replaced frequently, it is economical that this part does not have to be modified for the application of the cooling solution according to the invention. Instead, the device itself can be manufactured or modified to have the internal channels and flow guide elements according to the invention. Since the device is not involved in the machining process, it experiences significantly less or even no wear compared to the tool. The device can therefore be used again and again over a long service life. The changes made to the material of the base body are therefore more economical in the long run than changes to a wearing part.The fact that the tool holder does not have to be modified to secure the tool and attach the device can mean, in particular, that no drilling or similar modifications to the tool holder are necessary, which advantageously means that an existing range of tool holders does not have to be replaced or adapted. Tools do not have to be recalibrated, which advantageously means that this does not result in a significant increase in setup time. Both the continued usability of an existing range of tool holders and the non-significant increase in setup time make the invention very economically attractive. Furthermore, the coolant circuit advantageously does not have to be interrupted when the tool holder is replaced. In particular, a part that is independent of the tool and tool holder can be transferred from one tool to another particularly easily.This can advantageously make it possible to use a device according to the invention for different tools without having to adapt each tool individually. However, it is of course possible and not excluded that channels for the cooling fluid are also built into the tool or tool holder.

[0019] For example, it can be provided that the tool holder has flow-guiding cavities, whereby the flow within the tool holder runs along a surface in contact with the tool. The inlet and outlet for the cooling liquid can be located on any surface of the tool holder. However, it can also be connected to the cooling unit, the base body and / or the clamping finger. It can therefore be provided that the inlet and outlet of the cooling liquid to the flow-guiding cavities within the tool holder runs via the device for cooling the tool and / or is directly adjacent to the tool holder. Additional flow-guiding cavities within the tool holder can advantageously contribute to particularly efficient cooling performance.

[0020] The presence of the base body in the device allows the device to have a manageable three-dimensional shape that can fulfill a secondary function, for example, as a clamping finger. In addition, the base body provides an interior space in which the internal channels can be freely arranged, e.g., in different planes with different angles of incidence to the contact section. Since the base body is a separate component from the contact element, different materials can be used for these two components. One material of the base body can be selected to be easy to machine or particularly economical. The material of the contact element, on the other hand, can be designed for maximum thermal conduction and very high temperature resistance.

[0021] The contact element is positioned so that it touches the tool when the fixture is connected to the tool. The material of the contact element can therefore be specifically selected for this purpose. Since an extremely highly conductive material can be cost-intensive, it is advantageous to provide the contact element separately from the main body of the fixture.

[0022] However, it can also be provided that the contact element and the base body are made of the same material, thus forming a material unit that serves as a whole for heat transfer. If the contact element and base body are made of the same material, a wall thickness of the contact element of < 1 mm, preferably < 0.5 mm, particularly preferably < 0.2 mm can be provided.

[0023] The material unit advantageously reduces the number of necessary manufacturing steps and achieves great flexibility in the geometric design of the contact element and / or contact surface between the tool and the cooling device. The reduced number of manufacturing steps advantageously reduces manufacturing costs, both through the elimination of assembly steps and / or joining processes and through the use of less cost-intensive materials for the contact element. Reducing the number of materials in contact also advantageously increases heat transfer, which can contribute to a particularly efficient cooling process. This also enables the use of smaller flow guide elements on the contact section.The wall thickness of < 1 mm in the presence of a material unit of contact element and base body advantageously enables effective heat transfer from the tool to the cooling liquid with a primarily high wall stability.

[0024] The preferred wall thickness of < 0.5 mm, when the contact element and base body are formed as a single material unit, advantageously achieves a particularly good ratio of heat transfer into the cooling fluid while maintaining high strength. This configuration is particularly preferred when the cooling device is used as a clamping finger.

[0025] Due to the particularly preferred wall thickness of < 0.2 mm in the presence of a material unit of contact element and base body, an increase in the heat flow into the cooling liquid is advantageously achieved, which is comparable to that of a separate contact element with a slightly higher wall thickness, which does not form a material unit with the base body.

[0026] A system peripheral can be connected to the inlet and outlet of the base body. This can include commercially available components (pump, hoses, condenser / chiller) or a customized arrangement for continuously pumping coolant into the device. The coolant can preferably circulate in a liquid circuit. This ensures that even if the coolant evaporates while flowing through the device, it is not lost to the atmosphere. This eliminates health risks and is particularly environmentally friendly.

[0027] By providing the device's internal channels with a contact section that is in contact with the contact element, this section can be specialized for maximum heat exchange. The use of a plurality of flow elements in the contact section of the internal channels enables a local taper of the cross-section of the contact section, which in turn causes a local increase in flow velocity. The shapes and positions of the flow elements can also be selected to stimulate the cooling fluid to form vortices, which increase the turbulence in this contact section.

[0028] The increased flow velocity and increased turbulence synergistically contribute to increasing the rate of heat transfer from the tool via the contact element into the cooling fluid, particularly by increasing the turbulent kinetic energy along the contact section. This increases the rate of heat dissipation from the tool and gives the inventive solution a surprising level of effectiveness compared to the prior art.

[0029] However, it can also be provided that the flow from the inlet, through the contact section, and then through the outlet functions without the arrangement of additional flow guide elements inside the contact section. In this case, the inlet, contact section, and outlet preferably function together as a flow guide element. This advantageously enables a particularly simple and cost-effective production of a device for cooling a tool with low flow resistance.

[0030] A "tool cooling device" within the meaning of the invention is preferably a device that can be used in conjunction with a tool to reduce the temperature of the tool during machining of the workpiece, in particular during turning of the workpiece. Preferably, the device is configured to reduce the local temperature of the tool at a contact point between the tool and the workpiece.

[0031] For the purposes of the invention, a "base body" is preferably a three-dimensional unit which consists essentially of a uniform material and is provided with an inlet, an outlet and internal channels, including the contact section. The base body preferably has larger dimensions than the contact element. More preferably, the base body has a thickness which is at least twice, preferably at least three times, the thickness of the contact element, wherein the thickness is measured in a direction which extends from a surface of the tool through the contact element and through the base body. Preferably, the base body has a length which is at least 110%, preferably at least 120% of the length of the contact element, wherein the length is preferably measured along a main flow direction through the contact section.The base body preferably has a width that is at least three times, preferably at least five times, the width of the contact element. The base body can preferably be formed with a recess for receiving the contact element, so that the base body surrounds the contact element from above and from one or more sides. In principle, the base body can surround one or all surfaces of the contact element, with the exception of the one intended for contact with the tool.

[0032] For the purposes of the invention, a "contact element" is preferably a plate made of a material that ensures higher thermal conductivity than the material of the base body. The contact element is preferably also particularly heat-resistant. The contact element is intended for contact with the tool on at least one of its sides, wherein the contact is preferably direct mechanical contact. An opposite surface of the contact element is provided for contact with the contact section of the inner channels of the base body. This opposite surface can also form part of the contact section, in particular a bottom surface thereof. The opposite surface of the contact element can alternatively be in contact with an independent solid bottom of the contact section, which is formed from the material of the base body or another material.Preferably, the contact element may also have a greater length and / or width than the contact section, so that it is in contact with the material of the base area at the boundaries of the contact section.

[0033] For the purposes of the invention, an "inner channel" is preferably a cavity extending between the inlet and outlet of the base body, wherein the inner channel defines a flow direction along its longitudinal axis. The cross-section of the inner channel can take any shape and be variable along the flow direction.

[0034] For the purposes of the invention, a "contact section" is preferably a cavity or a recess in the base body, along which a cooling liquid guided through the internal channels is passed on its path between the inlet and the outlet. The contact section is in contact with the contact element, wherein this contact is preferably direct. In the case of direct contact, for example, a bottom surface of the contact section is in mechanical contact with the contact element, or the contact element forms a bottom surface of the contact section, so that no further components are interposed between the cavity of the contact section and the contact element. This supports rapid heat transfer from the contact element to the cooling liquid.

[0035] For the purposes of the invention, a "flow guide element" is preferably a three-dimensional geometric element (also called a "geometric figure") that causes a local taper of the cross-section of the contact section. The flow guide element is connected to or protrudes from at least one inner wall of the contact section. For example, the flow guide element is connected to a bottom surface, a side wall, or both side walls of the contact section. The flow guide element preferably has a geometric shape that is configured to increase turbulence at least locally in the contact section and preferably to increase turbulent kinetic energy in a region adjacent to the contact element. The flow element can have a regular or irregular geometric shape.

[0036] In a preferred embodiment of the invention, the contact element forms an inner wall of the contact section, wherein one or more flow guide elements are preferably also in contact with the contact element, are permanently connected to it, or form part of the contact element. Preferably, several flow guide elements are configured for conductive heat transfer from the contact element to the cooling fluid. It is particularly preferred that the flow guide elements be made of the same material as the contact element or an alternative material with high thermal conductivity. This advantageously enables particularly efficient heat transfer and uniform temperature distribution.

[0037] When the contact element forms an inner wall (specifically, a "bottom surface") of the contact section, contact between the contact element and the cooling fluid is achieved without an additional layer. This allows the cooling fluid to be brought even closer to the tool, especially to the contact area with the highest heat. Because the contact element has high conductivity, its temperature is the same as or very close to that of the tool. A high temperature gradient is achieved between the contact element and the cooling fluid, which supports high heat flow and excellent cooling.

[0038] By having one or more flow guide elements in contact with the contact element, permanently bonded to it, or forming part of the contact element, heat transfer from the tool to the coolant can be increased. Since the flow guide elements may have a more complex geometry and a larger surface-to-volume ratio than the contact element, they can also increase the interface area between the contact element and the coolant.

[0039] In a further preferred embodiment of the invention, flow guide elements protrude from an inner wall of the contact section, in particular from a base or from the contact element. The flow guide elements preferably create a local taper of a cross-section of the contact section. Preferably, at least one surface of a flow guide element forms an outer angle of 90° to 175°, in particular of 100° to 150°, with the inner wall of the contact section. The inner angle can therefore preferably be between 5° and 90°, in particular 30° and 80°, and particularly preferably between 40° and 60°. This surface of the flow guide element is preferably directed downstream.A surface of the flow guide element facing upstream may also have internal and external angles in the same preferred ranges, wherein the upstream surface may have an identical angle to the downstream surface, in particular in the case of an isosceles triangular prism, a rounded triangular prism or a symmetrical trapezoidal prism.

[0040] It was surprisingly found that flow guide elements with the aforementioned preferred angles lead to flow separation and thus to forced vortex formation. Furthermore, positioning flow guide elements on a bottom of the contact section, particularly on the contact element, leads to vortex formation in the immediate vicinity of the contact element, so that the turbulent kinetic energy in this region is particularly increased. This contributes to maintaining a high temperature gradient between the contact element and the majority of the cooling fluid.

[0041] These preferred shapes and angles therefore lead to a particularly advantageous optimization of flow dynamics and improved heat transfer through turbulence in the flow. The preferred angles advantageously minimize dead zones (zones where the coolant stagnates), thereby promoting a particularly even distribution of the coolant.

[0042] In a further preferred embodiment of the invention, flow elements are positioned along one or more inner walls of the contact section. Preferably, one or more flow elements are positioned such that at least one of their surfaces is exposed to a cooling fluid flowing along the contact section and / or a cooling fluid entering the contact section, preferably such that the cooling fluid is directed onto the contact element. This advantageously enables particularly efficient cooling of the contact element.

[0043] In a further preferred embodiment of the invention, at least one flow guide element is connected to two parallel inner walls of the contact section. Preferably, the flow guide element is simultaneously separated from the other inner walls of the contact section, in particular so that a free space is created between the flow guide element and the contact element. The two parallel inner walls to which the flow guide element is connected are preferably substantially orthogonal to the contact element. For the purposes of the invention, such a flow element is referred to as an "exposed flow element."

[0044] The use of exposed flow elements enables the generation of an additional secondary flow, particularly through the free space between the exposed flow element and the bottom of the contact section, thereby locally increasing the flow velocity and turbulence. This further enhances heat transfer. In a further preferred embodiment of the invention, one or more inner walls of the contact section have at least one cavity. The cavity preferably represents a local enlargement of the cross-section of the contact section, with each cavity preferably being delimited by separation edges. The separation edges preferably form an external angle of between 90° and 175° to the respective inner wall in which they are present.

[0045] Preferably, the cavity comprises a different material than the base body. For example, the cavity may comprise an insert or coating made of a different material, with the other material preferably having a higher thermal conductivity than the material of the base body. Preferred materials for the cavity include copper, diamond, silver, or combinations thereof. These materials can advantageously enable rapid heat dissipation.

[0046] It may also be preferred that the cavity is positioned between inlets or between an inlet and an outlet from and out of the contact section.

[0047] The separation edges of the cavity have a positive influence on flow separation and can be adjusted by varying the obtuse outer angle to the inner wall of the contact section. Furthermore, this can be achieved by shifting the separation edge, in particular by shifting the tip of the separation edge, toward a feed or a subsequent cavity.

[0048] Vortices can form within the cavity, generating turbulent flow. The cavity's stall edges can promote this vortex formation by maintaining an upstream stall edge's outer angle between 90° and 175°. An orthogonal or low outer angle, e.g., between 90° and 120°, can cause impingement flow and thus particularly strong turbulence. The upstream stall edge's angle can also serve to direct the cooling fluid toward the contact element, causing it to impinge on a portion of the contact section's bottom surface and form vortices adjacent to the contact element.

[0049] It has also been shown that the combined use of cavities and flow guide elements synergistically increases turbulence along the contact section. Cavities and flow guide elements can be positioned within the contact section, particularly between inlets or between inlets and outlets, to adjust the flow of the cooling fluid and thus increase the heat flow or cooling performance. The integration of cavities and flow guide elements enables a uniform temperature distribution within the cooling fluid across the entire cross-section of the contact section.

[0050] Furthermore, the cavities and flow guide elements result in forced flow deformation through separation effects and vortex formation, equivalent to impingement flow. These separation effects and vortex formation direct the main flow toward the underside of the contact section (especially toward the contact element). Furthermore, the cavities and flow guide elements enable targeted adjustment of the flow cross-section of the contact section, which positively influences the flow velocity and turbulent behavior with regard to cooling performance.

[0051] In a preferred embodiment of the invention, the cooling fluid is supplied to the contact section via a single inlet and removed from the contact section via a single outlet. In such an embodiment, it may be preferable to arrange several cavities in a row between the inlet and outlet along an inner wall of the contact section. This makes it possible to realize surprisingly effective turbulence effects with minimal pressure loss.

[0052] The length of the cavity in the flow direction or along a longitudinal axis of the contact section can be selected to control the turbulence effects. Preferably, the length of the cavity is designed to increase the turbulent flow at a bottom surface of the contact section or at the contact element.

[0053] In a preferred embodiment of the invention, the contact section comprises a plurality of cavities, wherein the length of each cavity is not less than 2% and not greater than 40% of the length of the contact section. Preferably, the length of each cavity is between 6% and 30%, in particular 15% and 25% of the length of the contact section. Preferably, the height (or "depth") of each cavity is not less than 10% and not more than 85% of the thickness of the contact section. Preferably, the height of the cavity is between 30% and 60%, in particular approximately 45% of the thickness of the contact section. However, a greater height of the cavity may also be preferred in order to increase the areal or volumetric proportion of the turbulent vortices, thereby enhancing the effect of forced turbulence. These preferred dimensions have proven particularly suitable for increasing the turbulence along the contact section.In addition, the preferred dimensions can advantageously contribute to particularly advantageous cooling performance while maintaining high structural integrity. For the purposes of the invention, a “cavity” is preferably a recess in one or more inner walls of the contact section, which locally enlarges the cross-section of the contact section. The cavity preferably has a floor or a ceiling surface at the deepest point of the recess, wherein the floor or ceiling surface preferably runs substantially parallel to the respective inner wall of the contact section. Other embodiments of the cavity without a discernible floor or ceiling surface can also be preferred, e.g. when the deepest point of the recess is merely a point between separation edges. This can be particularly the case when one or more separation edges of the cavity have a very gentle gradient.

[0054] In a further preferred embodiment of the invention, to achieve a targeted backflow of the cooling fluid in the contact section and to increase turbulence, an inner angle is formed at a downstream separation edge in a cavity, wherein the inner angle is between 5° and 60°. This angle enables a gentle gradient between the inner wall of the contact section and the lowest point of the cavity. Preferably, the downstream separation edge seamlessly transitions from its lowest point through an inner radius in an upstream corner of the cavity back to the height level of the inner wall. This arrangement has been shown to increase turbulence particularly effectively.

[0055] In some preferred embodiments of the invention, an exposed flow element is arranged in the cavity with the separation edge and the inner radius as described above. Preferably, the exposed flow element is placed in a region of the radius.

[0056] In a further preferred embodiment of the invention, the cavities with the tear-off edge, with the slight slope and the rounded inner corner, as described above, are arranged directly one behind the other.

[0057] In the sense of the invention, a “tear-off edge” (also called “run-out edge”) preferably represents a transition from an inner wall of the contact section to the lowest point of the cavity, in particular to a floor or ceiling surface of the cavity.

[0058] In a further preferred embodiment of the invention, the flow guide elements have a prismatic, pyramidal, polyhedral, spherical, or ellipsoidal shape, or a combination thereof. "A combination thereof" preferably means that the same flow guide element has features of different shapes. It may also be preferred to use flow elements with different shapes in the contact section.

[0059] The shape of the flow guide elements is preferably such that they have at least one first inclined or curved surface upstream and at least one second inclined or curved surface downstream. However, the number of surfaces of the flow guide elements is not limited. Particularly preferably, at least some flow guide elements have a prismatic shape with an isosceles triangular cross-section and preferably a rounded tip. The prismatic shape is preferably oriented orthogonally to the longitudinal axis of the contact section, such that a first side of the triangle is directed upstream, a second side of the triangle is directed downstream, and a third side of the triangle faces a bottom surface or is connected to the bottom surface of the contact section or the contact element.Preferably, an interior angle between the third side of the triangle and the first side of the triangle is between 5° and 85°, in particular between 5° and 60°. Preferably, the interior angle between the third side of the triangle and the second side of the triangle lies within the same preferred range. This allows for the generation of a particularly advantageous turbulent flow, while at the same time advantageously allowing for simpler production.

[0060] In a preferred embodiment of the invention, the interior angle of the triangle between the first and third sides (i.e., upstream) is greater than the interior angle of the triangle between the second and third sides (i.e., downstream). This enables an impact flow of the cooling fluid onto the flow guide element and a subsequent guidance of the cooling fluid (e.g., from the supply or from a cavity) toward the contact element.

[0061] The flow separation through the flow guide element can be modified, in particular, by adding a feature such as a radius between the first and second sides of the triangular cross-section, so that the turbulent flow can be modified. In a further preferred embodiment of the invention, a ratio of a height to a width of the flow guide elements is between 1:10 and 3:1. This ensures a surprisingly effective balance between a local cross-sectional reduction of the contact section and a suitable angle of impact between the cooling liquid and the flow guide element. When selecting the shape and size of the flow guide element, it is particularly preferred that the outer angle of the upstream-facing surface of the flow guide element is no greater than 175° or that the inner angle is at least 5°. This enables impingement flow.

[0062] In a further preferred embodiment of the invention, a highly thermally conductive ductile material such as a copper alloy can be advantageous for the flow guide elements. Furthermore, geometries such as cylinders, prisms, irregular sponge shapes, or airfoil profiles can be precisely realized in the contact section.

[0063] In a further preferred embodiment of the invention, the flow-guiding elements locally reduce the cross-section of the contact section by at least 20%, in particular at least 30%. The flow-guiding elements therefore represent more than mere irregularities on the inner surfaces of the contact section. Rather, they are individual elements of significant size that are capable of significantly redirecting the flow of the cooling fluid. This can advantageously contribute to an increased flow velocity. Furthermore, a particularly uniform temperature distribution can be advantageously achieved.

[0064] In a further preferred embodiment of the invention, the contact element comprises a material which has a thermal conductivity of at least 100 W rrr 1 K- 1 and has a melting point of more than 600°C, wherein the material is preferably selected from the group consisting of diamond, copper, gold, silver, aluminum, or alloys of copper, gold, silver, or aluminum. Diamond is particularly preferred. These preferred materials have proven particularly efficient at transporting heat from the tool to the cooling fluid. At the same time, these materials are particularly heat-resistant and have the mechanical strength to withstand the vibrations of the tool.

[0065] The contact element is connected to the base body, for example, by clamping, screwing, or soldering, but preferably by adhesive bonding. The contact element is preferably integrated into the base body and forms a bottom surface of the contact section. It is further preferred that the contact element be in direct surface contact with the tool. Taking into account the thermal and mechanical properties of the contact element, the contact element should preferably be designed as thin as possible. The use of one of the preferred materials makes it possible to keep the thermal latency as low as possible.

[0066] In a further preferred embodiment of the invention, the thickness of the contact element is up to 2 mm, in particular up to 0.5 mm. With such a thickness, the thermal latency of the contact element can be kept particularly low, so that the heat from the tool is efficiently transported into the cooling liquid. By minimizing the contact element thickness, the heat flow from the tool into the contact section is further increased according to Fourier's law. Given the properties of the selected material, the temperature of the tool, and the temperature of the cooling liquid, the person skilled in the art can select a suitable thickness for the contact element in order to keep the thermal latency low while maintaining high thermal conduction.

[0067] The temperature difference at the contact element along the flow axis in the contact section is preferably not more than 20 K, in particular not more than 5 K.

[0068] In a further preferred embodiment of the invention, a surface of the contact element facing the contact section has a roughness between 0.1 pm and 200 pm, in particular between 25 pm and 50 pm. Such a roughness can correspond to the grain size of an untreated CVD diamond layer. The surface roughness of the contact element enables increased heat transfer to the cooling fluid.

[0069] In a further preferred embodiment of the invention, the distance between the contact element and the contact surface of the tool is selected to be as small as possible. This distance is preferably no more than half the distance between two symmetrically opposite tool edges.

[0070] Preferably, a surface of the contact element facing the tool has a roughness of less than 0.1 pm, in particular between 0.01 pm and 0.06 pm. This surface is preferably polished. This enables optimal, seamless contact between the contact element and the tool, thus achieving good heat conduction.

[0071] In a further preferred embodiment of the invention, the surface of the contact element facing the tool covers at least 10% and up to 100% of the surface of the tool. Particularly preferably, the contact element is in contact with at least the cutting face of the tool. However, it may also be preferred for another surface of the contact element facing the tool to cover between 10% and 100% of the surface of the tool to be cooled. This allows for the targeted use of cost-intensive materials such as diamond, whereby the contact section can be limited to generate a high flow velocity.

[0072] Preferably, a "surface to be cooled" of the tool is the rake face, a flank face, and / or a surface in contact with a tool holder. Particularly preferably, the surface to be cooled is the rake face.

[0073] The internal channels of the device can be divided into different sections depending on the flow direction, particularly with respect to the contact element. One or more sections of the internal channels that carry cooling fluid from the inlet to the contact element can be referred to as "supply channels" or "supplies." One or more sections of the internal channels that carry cooling fluid away from the contact element can be referred to as "discharge channels" or "discharges." The contact section is preferably arranged between the supply channels and the discharge channels in contact with the contact element.

[0074] In a further preferred embodiment of the invention, the one or more inner channels comprise one or more, preferably 1 to 15, in particular 3 to 8, inlets and one or more outlets. The inlets are preferably arranged in an inlet plane above an outlet plane occupied by the contact section and / or outlets. The arrangement of the inlets and outlets in different planes is preferably made possible by sufficient dimensions of the base body. It should be noted that the inlets do not have to run parallel to the outlets. Rather, they can open into the contact section from different planes. Furthermore, the inlets and outlets can be rectilinear or have a spatial course.This allows the feed lines to run at least partially obliquely to the contact element, allowing cooling fluid to impinge on a bottom of the contact section, which bottom can be formed by the contact element itself. If the contact element represents a lower part of the device, the "feed plane" is preferably a higher plane above the "discharge plane."

[0075] In a further preferred embodiment of the invention, the feeds open into the contact section, with a flow direction of the feeds preferably being arranged at an angle of 0° to 90°, in particular 30° to 60°, relative to the surface of the contact element facing the tool. The flow direction is preferably viewed in a plane orthogonal to the surface of the contact element.

[0076] By feeding the cooling liquid into the contact section at the preferred angles, an impingement flow occurs at the contact element. Furthermore, the shapes, sizes, and positions of the flow-guiding elements and / or cavities can act synergistically with the oblique feed to ensure increased turbulence in the contact section. The flow-guiding elements lead to flow separation and thus to forced turbulence. It may be particularly preferred for the flow-guiding elements to be arranged opposite the feed and / or opposite one or more cavities. This may mean that the flow-guiding elements are placed on a bottom surface of the contact section, while the feed or cavity is located in the same longitudinal position in a top surface of the contact section.Alternatively, this can also mean that the flow guide elements are exposed at a feed or cavity. Such an arrangement allows the flow guide elements to be exposed to both the feed or cavity and the main flow direction along the contact section, further increasing turbulence.

[0077] The cross-sections of the inlets and outlets can have any shape, such as circular, elliptical, rectangular, or free-form. A circular or elliptical cross-section is particularly preferred. Such a cross-section can enable laminar flow and minimize pressure losses due to friction between the cooling fluid and the inner walls of the channels.

[0078] In a further preferred embodiment of the invention, the inlets and outlets have a diameter between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm, in particular between 0.5 mm and 2 mm. Such small diameters enable very high flow velocities compared to the volumetric flow rate of the cooling fluid used. This makes the cooling process surprisingly efficient. In a further preferred embodiment of the invention, the inlets are tapered. This reduces the pressure loss along the inlet and increases the flow velocity of the cooling fluid into the contact section.

[0079] It may be preferred that the leads have thermal insulation, for example in the form of a corresponding coating, and / or be configured to minimize convection losses. The material of the base body and / or its coating can also be selected for thermal insulation of the leads. This thermal insulation makes it possible to prevent unwanted heating of the cooling fluid and condensation thereof due to the ambient temperature. The temperature difference between the cooling fluid and the contact element in the contact section can thus be maximized.

[0080] Preferably, there are at least one inlet and one outlet for the coolant transport through the contact section. This advantageously reduces the required operating pressure within the cooling circuit due to larger cross sections through the separation of the inlet and outlet compared to, for example, concentric bores. This is particularly advantageous if the flow velocity is to be varied in order to increase heat transfer. The inlet and outlet can be arranged horizontally, vertically, or at any angle to one another. This advantageously offers flexibility in the design of the cross sections of the inlet and outlet within the base body. Inlet and outlet cross sections should preferably be selected as large as possible in order to maximize the volume flow of the coolant at the maximum permissible operating pressure.

[0081] In a further preferred embodiment of the invention, the invention comprises 1 to 3 outlets from the contact section, with the use of a single outlet being particularly preferred. The cross-section of the outlet is preferably selected to be as large as possible, but should not exceed twice the cross-section of the outlet from the base body. Preferably, the cross-section of the outlet does not exceed the cross-section of the outlet. This ensures a low system pressure from the outlet. It may also be preferred for the flow through the outlet and / or out of the outlet of the base body to be a laminar flow. This reduces the pressure differences and loads on the downstream components of the system periphery for coolant treatment.

[0082] In a further preferred embodiment of the invention, the cross-section of the outlet is equal to or larger than the cross-section of an individual inlet. Particularly preferably, the cross-section of the outlet does not exceed the combined cross-section of all inlets. The outlet preferably opens into a longitudinal extremity of the contact section, preferably in the last 30% of the length of the contact section, viewed from any direction.

[0083] Preferably, the inlets and outlets are connected to the contact section at one end and to the inlet or outlet of the base body at another end. The inlet and outlet preferably each comprise a connection for connecting the device to a system peripheral. In some preferred embodiments of the invention, the device comprises a plurality of contact elements and a plurality of contact sections, for example, at least two contact elements with two associated contact sections, at least three contact elements with three associated contact sections, or more. It may also be preferred that the number of contact elements does not correspond to the number of contact sections; for example, a plurality of contact sections may be in contact with different areas of the same contact element.

[0084] In a further preferred embodiment of the invention, the contact section has a longitudinal axis. In this embodiment, the contact section comprises a plurality of inlets, wherein a first inlet opens into the contact section at a different lateral distance from the longitudinal axis of the contact section than a second inlet. In other words, two or more inlets open into the contact section at different lateral positions. The lateral distance of the center of the cross-section of each inlet can be shifted from the longitudinal axis (also called "centerline") of the contact section. Preferably, the center of the cross-section of no inlet extends beyond a bottom surface of the contact section. By varying the lateral positions of the inlets, vortices can form throughout the contact section as the flow from one inlet meets the flow from another.This in turn increases turbulence and the cooling rate.

[0085] In a further preferred embodiment of the invention, all inlets open into the longitudinal axis of the contact section. This can lead to a more predictable flow regime, with the angle of incidence of the inlets, the flow guide elements, and / or the cavities determining the vortex formation.

[0086] If multiple feeds are used, the spacing between the feeds can be selected as needed. It may be preferable for the feeds to be equidistant in the longitudinal direction of the contact section. Likewise, the spacing between one feed and the next can be varied.

[0087] The contact section may have any shape, with the smallest dimension of the contact section being its thickness. The contact section preferably has a longitudinal axis that represents the main current direction. Preferably, inlets are arranged along the longitudinal axis (optionally offset therefrom), while an outlet is arranged close to one end of the longitudinal axis. The cross-section of the contact section is preferably the size of its opening in a plane transverse to the longitudinal axis. Preferably, the cross-section of the contact section is between 0.008 mm 2 and 20 mm 2 , especially 0.2 mm 2 and 3.5 mm 2 . If the cross-section varies over the length of the contact section, these values ​​preferably represent average values.

[0088] A bottom surface (or "base surface") of the contact section can be circular, elliptical, rectangular, or free-form. The bottom surface is preferably rectangular, and edges of the contact section can be designed with a corner radius. This can reduce pressure losses. In a further aspect, the invention relates to a system for cooling a tool for machining a workpiece, according to one of the preceding claims, as well as a tool and means for connecting the device to the tool. Furthermore, the system comprises a fluid circuit for conveying a cooling liquid into the inlet and for conducting the cooling liquid out of the outlet of the device for cooling the tool.

[0089] The system according to the invention is based on a closed circuit, through which an environmentally friendly coolant preferably flows. This eliminates the need to supply external cooling lubricant (CLU) to the machining zone. The heat generated during machining is dissipated both by the chip and by the closed internal cooling system. Heat transfer for internal cooling occurs indirectly through conduction and forced convection. This is made possible by the contact between the tool and the tool cooling fixture, as well as by the coolant flowing through the fixture and the fluid circuit (part of the "system periphery").

[0090] The fluid circuit is preferably used to treat, move, and / or temper the coolant. The advantage here is that the coolant remains in the fluid circuit. This significantly reduces the operating costs for the system compared to flood cooling. Furthermore, the limited cross-sections of the fluid circuit and the internal channels of the device serve to increase the flow velocities and flow pressure. Compared to flood cooling, the required pressures and flow rates are up to 100 times lower. This allows the pumping capacity of the fluid circuit to be significantly reduced. Furthermore, significantly smaller quantities of coolant are required. The required quantities of coolant can be up to 10 times lower than with flood cooling.The closed circuit design and targeted heat dissipation result in significant advantages in terms of energy and resource consumption.

[0091] The means for connecting the device to the tool are preferably detachable means. These can, for example, comprise a screw which preferably passes through the base body, the contact element and the tool. When using a screw to connect the device to the tool, the screw can therefore preferably serve to fix both the device and the tool at the same time. This advantageously reduces the number of additional elements. Furthermore, a particularly precise positioning of the device in relation to the tool can be achieved. It can also be provided that an additional or separate screw is used for the connection. This advantageously enables particularly great flexibility in the use and / or positioning of the device. Alternatively, the device can also be connected to the tool by clamping or gluing.This advantageously enables particularly flexible and simple positioning of the device. The device can be used as a clamping finger or as an additional component that does not affect any existing clamping systems. The cooling device can be positioned above, below, or in combination with the tool. The terms "above" and "below" refer to the typical orientation of the tool during use with a workpiece. This orientation is known to those skilled in the art.

[0092] The device can also be positioned laterally and / or on multiple surfaces of the tool. This advantageously allows for particularly effective cooling of the tool. Multiple surfaces can also be cooled simultaneously, for example, by using multiple cooling elements and / or a single cooling element that can extend across multiple surfaces.

[0093] Depending on the positioning of the device, the device can also fulfill a dual function, for example, clamping and / or cooling. This advantageously allows the number of elements used to be kept as low as possible, thereby minimizing any negative influence on the process behavior caused by the cooling device. In particular, a negative influence on the vibration behavior of the tool holder, the cutting depth (a P ), and / or setup time can be avoided.

[0094] Alternatively, the fixture can also be an additional component that has no additional function in the tool system other than cooling and does not affect the existing clamping system. This advantageously allows the fixture to be integrated particularly easily into existing tool systems.

[0095] In a preferred embodiment of the invention, the system comprises a tool seat, wherein the cooling device functions as a tool seat or is integrated into a tool seat. According to this embodiment, the device can cool the tool from below.

[0096] One advantage of the system is that no modification of the tool, tool holder, or optional tool seat is necessary. This allows the use of standardized components such as tools and tool holders.

[0097] In a further preferred embodiment of the invention, the cooling device is configured as a tool seat, which is preferably designed for cooling the tool from below. This configuration can be additionally combined with another cooling device, designed as a clamping finger or otherwise connected to the tool from above, so that the tool is cooled from above and below. Such cooling devices can interact synergistically with each other to reduce the temperature of the tool.

[0098] In a further preferred embodiment of the invention, the device for cooling a tool functions as a clamping finger for clamping the tool. In this case, the device can be integrated into a clamping finger. The clamping finger can also be modified to implement the features of the device.

[0099] The base body of the device preferably comprises a metallic material. However, this can also have a thermally insulating layer. If the device functions as a clamping finger for clamping the tool, the base body is made of steel or a material with similar thermal and / or mechanical properties. This ensures the necessary stability to withstand mechanical stresses on the tool.

[0100] When the device is used as an additional component that does not serve to clamp the tool, the base body can comprise a metallic material such as steel or a thermally insulating material such as plastic. As explained for the device, the use of a thermally insulating material has advantages in maximizing the temperature difference between the cooling fluid and the contact element in the contact section.

[0101] In a further aspect, the invention relates to a method for cooling a tool using a system according to the invention. In the method, a cooling liquid is continuously fed into the inlet of the device for cooling the tool at a volume flow between 0.01 l / min 1 and 20 I mim 1 introduced, wherein the cooling liquid circulates in a closed circuit through the internal channels of the device. Preferably, the cooling liquid is delivered to the inlet of the device at a pressure of up to 10 bar, in particular up to 4 bar.

[0102] Heat dissipation from the tool can be achieved with either an uncooled or a tempered cooling fluid. In this case, the use of a cooling fluid with a high specific heat capacity (c P), such as water, of any quality, such as demineralized, deionized, or ultrapure water, is preferred. Environmentally friendly additives are used to inhibit corrosion in preferred embodiments of the process. Furthermore, when using cooling fluid temperatures below freezing, the addition of further additives or glycols is preferred. The mechanical and thermal properties of the cooling fluid mixed with additives are preferably designed to minimize the influence on the properties of the water.

[0103] In a further preferred embodiment of the invention, the volume flow of the cooling liquid is 0.01 l mim 1 up to 4 I mim 1 , preferably 1 I mim 1 up to 3 I mim 1These flow velocities ensure particularly rapid heat dissipation and work synergistically with the preferred dimensions of the contact section, cavities, and flow guide elements to create turbulence effects. At the same time, the flow velocities are low enough to allow the use of particularly economical pumps.

[0104] In a further preferred embodiment of the invention, the cooling liquid is tempered to -20 °C to 35 °C, with a temperature between 5 °C and -10 °C, in particular approximately -5 °C, being particularly preferred.

[0105] In a further preferred embodiment of the invention, the method for cooling a tool using the system according to the invention is combined with a flood cooling and / or a cooling lubrication strategy. This can synergistically improve cooling.

[0106] The person skilled in the art will recognize that preferred features and advantages of the device according to the invention also apply to the system according to the invention and the method according to the invention, and vice versa. Detailed description

[0107] In the following, the invention will be explained in more detail using examples and illustrations, without being limited to these.

[0108] Short description of the figures

[0109] Fig. 1 Schematic representation of a system for processing a workpiece under

[0110] Cooling according to a preferred embodiment of the invention

[0111] Fig. 2 Schematic representation of a cross-section of a device for cooling a

[0112] Tool according to a preferred embodiment of the invention

[0113] Fig. 3 Schematic representation of a plan view of a device for cooling a

[0114] Tool according to another preferred embodiment of the invention

[0115] Fig. 4A Schematic representation in plan view of a contact section according to a preferred embodiment of the invention

[0116] Fig. 4B Schematic representation in plan view of a contact section according to an alternative preferred embodiment of the invention

[0117] Fig. 5A Schematic representation in plan view of a device for cooling a tool, showing a preferred deviation of the position of the contact element from a center point.

[0118] Fig. 5B Schematic representation in plan view of a device for cooling a tool, showing a preferred small distance between the heat source of the tool and a base surface of the contact element.

[0119] Fig. 5C Schematic representation of a cross-section through a device for cooling a tool, showing a preferred deviation of the position of the contact element from a center point.

[0120] Fig. 5D Schematic representation of a cross section through a device for cooling a tool, showing a preferred small distance of the heat source of the tool from a base surface of the contact element.

[0121] Fig. 6 Schematic representation of a contact section of the device according to a preferred embodiment of the invention.

[0122] Fig. 7 Schematic representation of a contact section of the device according to another preferred embodiment of the invention.

[0123] Fig. 8 Schematic representation of a contact section of the device according to another preferred embodiment of the invention. Fig. 9 Schematic representation of a preferred embodiment of a

[0124] flow guide element

[0125] Fig. 10 Schematic representation of another preferred embodiment of a flow guide element

[0126] Fig. 11 Schematic representation of another preferred embodiment of a flow guide element

[0127] Fig. 12 Schematic representation of another preferred embodiment of a flow guide element

[0128] Fig. 13 Schematic representation of a preferred embodiment of a cavity

[0129] Fig. 14 Schematic representation of another preferred embodiment of the cavities

[0130] Fig. 15 Schematic representations of another preferred embodiment of the cavity

[0131] Detailed description of the illustrations

[0132] Figure 1 shows a schematic representation of a system for processing a workpiece under cooling according to a preferred embodiment of the invention. Shown are a device 1 for cooling the tool and a tool 2. The device 1 comprises a base body 4. The base body 4 of the device is in direct contact with the tool 2. Internal parts of the device 1 are not visible in this view. However, the base body 4 comprises an inlet and an outlet, which are fluidly connected to the system periphery 3. The tool 2 is arranged on a tool seat 6, wherein the device 1 is configured as a clamping finger for clamping the tool 2 and the tool seat 6 on the tool holder 5. The tool holder 5 can have a relevant interface to the tool seat 6 and / or tool 2, such as a polygonal shank taper or square.

[0133] A cooling fluid prepared by the system periphery 3 passes through the device 1 and is then returned to the system periphery 3. This creates a fluid circuit for tool cooling.

[0134] Fig. 2 shows a schematic cross-section through the device 1 along a supply channel 8 (see Fig. 3 for reference numerals). The supply channel 8 takes a spatial course 11 through the base body 4 and opens into the contact section 7 with an angle of incidence 12 of 60°. The contact section 7 represents a cavity in the device 1 and is arranged directly above the contact element 10, wherein the contact element 10 forms a bottom surface of the contact section 7. The contact section 7 is fluidly connected between the inlet and the outlet of the base body by internal channels, wherein the internal channels comprise at least one supply 8 and at least one discharge 9 (not shown, see Fig. 3). The contact section 7 is further provided with flow guide elements which locally increase the turbulence and flow velocity of the cooling liquid through the contact section.In this embodiment, the contact element 10 is a diamond plate with a thickness 13 of 0.5 mm. The contact element 10 transfers the heat from the tool 2 to the cooling fluid, so that a temperature difference along the longitudinal axis of the contact element 10 is no more than 5 K.

[0135] Fig. 3 shows a schematic representation of a device 1 in plan view with its contact section 7, showing internal components that are not necessarily on the same plane. The device 1 comprises an inlet 14, which is configured as a fluid connection to a system periphery 3. An inlet 8 with a constant diameter (solid line) connects the inlet 14 to the contact section 7. The dashed line shows an alternative embodiment, wherein the diameter of the inlet 8 is not constant, but tapers in the direction of flow. The contact section 7 lies above a contact element 10, which has a slightly greater width and length than the contact section. The contact section 7 is connected to an outlet by means of an outlet 9. The longitudinal and central axes of the inlet and outlet are shown, which represent a main flow direction of the cooling liquid through the base body.

[0136] Figures 4A and 4B show two alternative embodiments of the opening of several feeds 8 into the contact section 7. In the embodiment according to Fig. 4A, the contact section 7 has a substantially rectangular base surface with rounded corners 19. A longitudinal axis 16 runs along the contact section 7 and defines a main flow direction. The contact section 7 is supplied with cooling liquid by means of at least one feed 8. If only one feed 8 is used, it preferably opens at or near one end of the longitudinal axis 16. The at least one feed 8 is shown by solid lines. At least one outlet 9 leads the cooling liquid away from the contact section 7 and is preferably positioned at or near another end of the longitudinal axis 16. Between the first feed 8 and the outlet 9, further feeds 8, in this case three, can be introduced. In the embodiment of Fig.4A, all of these leads 8 are equidistant along the longitudinal axis 16. This means that the distance 17 between consecutive leads 8 is always the same. Furthermore, all leads open into the contact section 7 such that their center point 15 lands on the longitudinal axis 16 without any lateral deviation.

[0137] According to the embodiment of Fig. 4B, however, the first and third feed lines 8 and the discharge line 9 open along the longitudinal axis 16. A variable deviation 18 of the centers 15 of the second and fourth feed lines 8 from the longitudinal axis 16 is provided.

[0138] Figures 5A to 5D show preferred relative dimensions and positions of the contact element 10 with respect to a tool. A base surface of the contact element 10 is designated by the reference numeral

[0139] 20 and has a rectangular shape, for example. The area 21 to be cooled within the entire tool surface 22 is shown in dashed lines in Fig. 5B. As shown in these figures, the base area 20 of the contact element 10 covers between 10% and 100% of the area to be cooled.

[0140] 21. To increase the cooling performance, the contact element 10 can encircle the respective surface 21 to be cooled on the cutting edge of the tool 2. This may require a shift in the position of the contact element 10 from the shown rectangle 20 to one end of the surface 21 to be cooled, wherein the shift is represented by the reference numeral 23. A projection of the device 1 beyond the respective surface 21 of the tool 22 to be cooled is possible, but this consequently leads to reduced cooling performance.

[0141] Figures 5A to 5D show a distance 24 between the contact element 20 and the contact area 25 on the rake face of the tool. The contact area 25 can be considered a heat source. Preferably, the distance 24 is kept as small as possible to create optimal heat transfer from the rake face to the cooling liquid. Displacing the contact element 20 over the distance 23 can make this possible. Furthermore, the distance 24 between the contact element 20 and the heat source 25 should be a maximum of half the distance between two symmetrically opposite edges of the tool 2. By reducing the distance 24, a negative influence on the chip flow can generally be avoided.

[0142] Fig. 6 shows a schematic cross-section along the longitudinal axis 16 of a contact section 7 according to a preferred embodiment of the invention. The flow of cooling fluid from the supply line 8 to the contact element 10 is indicated by reference numeral 26. This flow occurs in a plane transverse to the viewing plane at an angle of incidence 12 of 90° to the bottom surface of the contact section 7. This maximum angle of incidence 12 realizes a high heat flow based on turbulence effects. Furthermore, by selecting such a large angle of incidence, the flow velocity can be selected to be lower while maintaining constant turbulence, which makes the technical solution particularly efficient.

[0143] Due to the temperature difference between the cooling fluid and the contact element 10 at the bottom surface 31 of the contact section 7, a thermal boundary layer forms along the bottom surface 31. The resulting temperature gradient and the thickness of the boundary layer influence the heat flow toward the cooling fluid. In this embodiment, the bottom surface 31 is a surface of the contact element 10. The cooling performance depends on the temperature difference of the contact element 10 along the flow axis in the contact section 7 and is less than 5 K. To further reduce the temperature difference, several feed lines 8 are used to supply a temperature-controlled cooling fluid along the entire contact section 7.

[0144] Cavities 27 are provided between successive inlets 8 and between the last inlet 8 and an outlet 9. These represent a local enlargement of the cross-section of the contact section 7 and are delimited by separation edges 32. Flow guide elements 28 designed as geometric figures are also used in front of the inlets 8 or between the inlets 8 on a bottom surface 31 of the contact section 7. By integrating cavities 27 and flow guide elements 28, a forced flow deformation is achieved through separation effects 29 and vortex formation 30. The impingement flow of the cooling liquid 26 from the inlets 8 and the inclined surfaces of the flow guide elements 28 and separation edges 32 guide the cooling liquid towards the bottom surface 31 for high heat transfer from the contact element 10. The areas 51 of the impact flow on the bottom surface are highlighted in dashed lines. Fig.Figure 7 shows possible variations of the separation edges 32 of the cavities 27. A main flow direction runs along the contact section 7 from right to left. Solid lines show an upstream outer angle of 90° between the separation edges 32 and the inner wall of the contact section 7 (the first three separation edges 32 on the right). The cooling fluid impacts these separation edges, creating vortices in the cavities 27. However, the flow behavior can be varied by varying the outer angles, for example, by shifting the tip 34 of a separation edge 32. Such a shift is indicated by an arrow pointing to the left. This also changes the obtuse angle 33 of the separation edge 32 in the downstream direction.Such variations in the shape of the separation edges 32 can be combined with the positioning and angling of the inclined surfaces of the flow guide elements 28 to guide the cooling liquid, in particular, to the bottom 31. Furthermore, Fig. 7, with reference numeral 35, shows a possible adaptation of the diameter of a feed 8, for example, by a taper, which causes the feed 8 to function like a nozzle, spraying cooling liquid at high speed into the contact section 7.

[0145] Fig. 8 shows further parameters of the cavities 27 that can be adjusted to change the flow regime. For example, the distance 36 between successive tips 34 of the stall edges can be changed to manipulate vortex generation near the bottom 31. Furthermore, the height or depth 37 of the cavity 27 can be adjusted to generate vortices with a larger radius.

[0146] Fig. 9 shows a schematic representation of a preferred embodiment of a flow guide element 28 according to the invention for realizing an impingement flow 26. The inlet 8 leads to an impingement flow 26 at the contact element 10. In order to control a mutual influence of the flow along the flow channel 7 and the flow of the inlet 8, flow guide elements 28 are implemented. The flow guide elements 28 lead to a separation of the flow and thus to forced turbulence. In this embodiment, the flow guide elements 28 are located in the region of the cavities 27, the cross-section of which is preferably described by an isosceles triangle with an internal angle 38 of a maximum of 60°. By adding a radius 37, the effect of the flow separation is changed, so that the turbulent flow is intensified.In a further preferred embodiment, the internal angles 38 of the flow guide element 28 are from 5° to 60°, so that the flow pattern changes both in the inlet 8 and in the separated flow 29.

[0147] Fig. 10 shows a schematic representation of a preferred embodiment of a flow guide element 28 according to the invention with different positions. The flow guide element 28 is preferably located along the flow channel, between the feed 8 and the outlet edge 32 of the cavity, with one side of the flow guide element 28 lying on the underside of the flow channel 31. If the distance 41 between the flow guide element 28 and the outlet edge 32 of the cavity 27 is reduced, the higher the resulting flow velocities are, whereby the position of the separation 29 of the cooling fluid is changed. Fig. 11 shows a schematic representation of a preferred embodiment of the flow guide element 28 with different heights 42 and widths 43 in order to achieve the desired resulting flow velocity. A reduction in the height 42 or an increase in the width 43 is possible.Particularly preferably, the angle 38 of the required edge for the separating flow 29 does not fall below 5°. The aspect ratio of height 42 to width 43 of the flow guide element 28 is preferably between 1:10 and 3:1.

[0148] Fig. 12 shows a schematic representation of a preferred embodiment of the flow guide element 28. Preferably, the flow guide element 28 is positioned collinearly with the contact element 10. The flow guide element 28 is preferably located on the central axis 11 of the feed line 8 or on a line parallel thereto. In a further embodiment, the flow guide element 28 is set free from the contact element 10, creating a free space 44. This leads to an additional secondary flow 45, which increases the flow velocity and turbulence in this area.

[0149] Fig. 13 shows a schematic representation of a preferred embodiment of the cavities 27 for implementing a targeted backflow of the fluid flow and for increasing turbulence in the flow channel on the side of the contact element 10. An angle 46 is introduced at the top 47 of the cavity, preferably with a size between 5° and 60°. In a further preferred embodiment, a radius is applied to the corners 48 of the cavity 27 to increase turbulent effects. Preferably, a flow guide element 28 is located within the cavity 27, based on the outlet edge 32, which has a vertical distance 49 of 15% to 90% measured from the underside of the flow channel 31 or the contact element 10. The flow guide element 28 does not touch the edges of the cavity 27 and lies freely in the flow channel. The preferred range extends from 20% to 40% of the vertical distance 49.The lower edge of the flow guide element 28 is preferably not located below the first outlet edge 32, depending on the flow direction. This allows the flow above and below the flow guide element 28 to be separated along the flow channel. A turbulent vortex with backflow preferably forms above the flow guide element 28, which increases the turbulent flow behavior on the underside of the flow channel 31.

[0150] Fig. 14 shows a schematic representation of a preferred embodiment of the cavities 27. The cavities 27 are arranged serially. The cavities 27 have both an angle 46 and a radius 48, so that the resulting flow pattern and the resulting turbulence on the underside of the flow channel 31 between the inlet 8 and the outlet 9 are reproduced along the flow channel 7.

[0151] Fig. 15 shows a schematic representation of a preferred embodiment of the cavity 27 and the flow guide element 28. The distance 50 between the center of the geometric figure 28 and the first outlet edge 32 is greater than 0 mm, so that a turbulent vortex with backflow can form in the upper fluid flow, which increases the turbulence of the flow below the flow guide element 28. With an increase in the size of the flow guide element 28 in the vertical direction and a resulting reduction in the vertical distance 49 between the flow guide element 28 and the outlet edge 32, the cross-section of the flow channel 7 is narrowed. This increases the turbulence on the underside of the flow channel 7. The corner radius enables the flow to separate within the cavity 27.

[0152] Reference symbol

[0153] 1 device for cooling a tool

[0154] 2 tools

[0155] 3 System peripherals

[0156] 4 basic bodies

[0157] 5 tool holders

[0158] 6 Tool seat

[0159] 7 Contact section

[0160] 8 feed channel

[0161] 9 Discharge channel

[0162] 10 Contact element

[0163] 11 Spatial course of the supply or discharge channel

[0164] 12 Angle of incidence between channel axis and base of the contact section

[0165] 13 Thickness of the contact element

[0166] 14 Inlet or outlet

[0167] 15 Cross-section of the supply or discharge channel

[0168] 16 Longitudinal axis of the contact section

[0169] 17 Distance between the center axes of the feed channels

[0170] 18 Distance between the central axis of a feed channel and the longitudinal axis of the contact section

[0171] 19 Edge of the contact section with corner radius

[0172] 20 Base area of ​​the contact element

[0173] 21 Surface of the tool to be cooled

[0174] 22 Plate shape of the tool

[0175] 23 Distance between a center point of the tool and the preferred center point of the contact element

[0176] 24 Distance between the contact element and the heat source of the tool, in particular the contact area of ​​the chip surface of the tool

[0177] 25 Contact area of ​​the tool's rake face

[0178] 26 Flow of the cooling liquid from the supply channel

[0179] 27 Cavity

[0180] 28 Flow guide element / geometric figure

[0181] 29 Flow separation

[0182] 30 Vortex formation

[0183] 31 Bottom / bottom of the contact section

[0184] 32 Lead-out or tear-off edge of the cavity

[0185] 33 Outer angle of the tear-off edge to the cavity

[0186] 34 Displacement of the tip of the tear-off edge from an orthogonal position towards a feed channel 35 Diameter of the feed or discharge channel

[0187] 36 Width of the cavity

[0188] 37 Height of the cavity

[0189] 38 Internal angle of a flow guide element to the inner wall of the contact section

[0190] 39 Displacement of the tip of the flow guide element by changing an internal angle to the inner wall of the contact section

[0191] 40 Position of the flow guide element

[0192] 41 Distance upstream between the tip of the flow element and the tip of the separation edge of the nearest cavity

[0193] 42 Flow guide element with reduced height

[0194] 43 Flow guide element with increased width

[0195] 44 Clearance between exposed flow guide element and contact element

[0196] 45 Secondary flow of the coolant through the free space

[0197] 46 Angle of an inclined inner wall of the cavity to the inner wall of the contact section

[0198] 47 Inner wall of the cavity

[0199] 48 Inner corners of the cavity

[0200] 49 Distance between an exposed flow guide element in the cavity and the contact element

[0201] 50 Distance upstream between the exposed flow guide element in the cavity and the nearest separation edge

[0202] 51 Impact flow towards the floor surface

Claims

PATENT CLAIMS 1. A device for cooling a tool (2), the device comprising a base body (4), a contact element (10), and at least one inlet into the base body (4) and one outlet from the base body (4), the inlet and the outlet being connected to one another by one or more internal channels in the base body (4), the device being connectable to the tool (2) such that the contact element (10) is in contact with the tool (2), and the one or more internal channels being configured to conduct a cooling liquid, characterized in that the one or more internal channels comprise a contact section (7), the contact section (7) being in contact with the contact element (10), the contact section (7) comprising a plurality of flow guide elements (28) configured to locally increase the turbulence and the flow velocity of the cooling liquid through the contact section (7).

2. Device according to claim 1, characterized in that the contact element (10) forms an inner wall of the contact section (7), wherein one or more flow guide elements (28) are preferably also in contact with the contact element (10), are permanently connected or form part of the contact element (10) and are configured for a conductive heat transfer from the contact element (10) to the cooling liquid.

3. Device according to one of the preceding claims, characterized in that the flow guide elements (28) protrude from an inner wall of the contact section (7), in particular from a base or from the contact element (10), and produce a local taper of a cross section of the contact section (7), wherein preferably at least one surface of a flow guide element (28) forms an outer angle of 90° - 175°, in particular 100° - 150°, to the inner wall of the contact section (7).

4. Device according to one of the preceding claims, characterized in that at least one flow guide element (28) is connected to two parallel inner walls of the contact section (7) and is separate from the other inner walls of the contact section (7), the two parallel inner walls being substantially orthogonal to the contact element (10).

5. Device according to one of the preceding claims characterized in that one or more inner walls of the contact section (7) have cavities (27) and the cavities (27) represent a local enlargement of the cross section of the contact section (7), wherein the cavities (27) are preferably delimited by tear-off edges (29), wherein the tear-off edges (29) preferably form an outer angle between 90° - 175° to the respective inner wall.

6. Device according to one of the preceding claims, characterized in that the flow guide elements (28) have a prismatic, pyramidal, polyhedral, spherical or ellipsoidal shape or a combination thereof, wherein a prismatic shape with an isosceles triangular cross-section and a rounded tip is preferred, wherein preferably a ratio of a height to a width of the flow guide elements (28) is between 1:10 and 3:

1.

7. Device according to one of the preceding claims, characterized in that the contact element (10) consists of a material which has a thermal conductivity of at least 100 W m _1 K' 1 and has a melting point of more than 600 °C, wherein the material is preferably selected from the group comprising diamond, copper, gold, silver, aluminum or alloys of copper, gold, silver or aluminum.

8. Device according to one of the preceding claims, characterized in that a surface of the contact element (10) facing the contact section (7) has a roughness of 0.1 pm - 200 pm, in particular 25 pm - 50 pm, and a surface of the contact element (10) facing the tool (2) has a roughness of less than 0.1 pm.

9. Device according to one of the preceding claims, characterized in that the one or more inner channels 1 - 15, in particular 3 - 8, comprise inlets (8) and one or more outlets (9), wherein the inlets (8) are arranged in an inlet plane above an outlet plane occupied by the contact section (7) and / or outlets (9).

10. Device according to the preceding claim, characterized in that the feeds (8) open into the contact section (7), wherein a flow direction of the feeds (8) is preferably arranged at 0° - 90°, in particular 30° - 60°, to the surface of the contact element (10) facing the tool (2).

11. Device according to one of the preceding claims, characterized in that the contact section (7) has a longitudinal axis and the one or more inner channels comprise a plurality of feeds (8), wherein a first feed opens into the contact section (7) at a different lateral distance (18) to the longitudinal axis (16) of the contact section (7) than a second feed.

12. Device according to one of the preceding claims, characterized in that the flow elements reduce the cross section of the contact section (7) locally by at least 20%, in particular at least 30%, wherein the cross section of the contact section (7) is preferably between 0.008 mm 2 - 20 mm 2, especially 0.2 mm 2 - 3.5 mm 2 amounts.

13. System for processing a workpiece with cooling, characterized in that the system comprises a device for cooling a tool (2) according to one of the preceding claims, a tool (2) and means for connecting the device to the tool (2), the system further comprising a fluid circuit for conveying a cooling liquid into the inlet and for guiding the cooling liquid out of the outlet of the device for cooling the tool (2).

14. System according to the preceding claim, characterized in that the device for cooling a tool (2) functions as a clamping finger for clamping the tool (2) or as a cooling unit, wherein the base body (4) of the device preferably comprises a metallic material.

15. A method for cooling a tool (2) using a system according to one of claims 13 or 14, characterized in that a cooling liquid is continuously fed into the inlet of the device for cooling the tool (2) with a volume flow between 0.01 l mi 1 - 20 I mim 1 is introduced, wherein the cooling liquid circulates in a closed circuit comprising the internal channels of the device.

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