Cooling attachment for work machines

Abstract

The invention relates to a cooling attachment (100) for releasably mounting on a working machine (200), the working machine (200) having a shaft (210) in which a rod-shaped tool (300) is guided in a rotary or hammer-like manner and which emerges from the shaft with its free end. The cooling attachment has a housing (110) which surrounds the working machine (200), in particular its shaft and the tool (300) which emerges therefrom, but only partially. Inside the housing a first cooling passage (120) is formed for guiding a coolant from an inlet opening to the tool which emerges from the free end (114) of the housing shaft. In particular, in order to improve the cooling of the tool while simultaneously avoiding cooling the workpiece to be machined with the tool, the invention proposes that at the free end of the housing shank, between the first cooling passage (120) and the second cooling passage (130), at least one connecting hole (150) is provided for diverting the coolant from the first cooling passage to the second cooling passage.

Description

[Technical Field]

[0001] The present invention relates to a cooling attachment for detachable attachment to a work machine, the work machine having a shaft in which a rod-shaped tool is guided in a rotary or hammering manner and extends from the shaft at its free end. Furthermore, the present invention relates to an apparatus consisting of a work machine combined with the cooling attachment according to the present invention, as well as a method for operating the apparatus. A work machine within the meaning of the present invention is, in particular, a dot marking machine that imprints a data matrix or code, formed for the purpose of simplified traceability, into a workpiece, in particular a forged workpiece, after the forging process. However, a work machine within the meaning of the present invention can also be a drill or a battery-powered screwdriver that drives typically exchangeable tools, such as screwdrivers, turning tools, or marking stamps. Depending on the tool, the work machine can be operated in a rotary or hammering mode. Turning tools or marking stamps are typically operated in a hammering mode, while screwdrivers are typically operated in a rotary mode.

[0002] The cooling attachment described above for a work machine is basically known in the prior art, for example, from German Patent Application No. DE 19703094 A1. The cooling attachment disclosed therein is used, in particular, for cooling hand-held machine tools, in particular for cooling steel pins extending from the shank of the hand-held machine tool and used for stamping or machining the surface of a workpiece. The cooling attachment disclosed therein has all the features recited in the preamble of claim 1. Specifically, the cooling attachment disclosed therein has an outer housing with continuous slits for the inflow or outflow of a coolant. The housing is preferably made of a material with relatively poor thermal conductivity, in particular plastic. In addition to the outer housing, the cooling attachment also has an inner housing. The inner housing surrounds the working area of ​​the work machine. The working area of ​​the work machine houses striking pins, which are percussion transmission elements that generate frictional heat during the percussion operation of the work machine and contribute to the heating of the work machine. The inner housing is fabricated from a relatively good thermally conductive material which ensures sufficient conduction of frictional heat away from the working area of ​​the work machine.

[0003] The cooling attachment known from this specification is designed to guide the coolant from the end of the housing near the work machine to the free end, where it is guided to the tool to be cooled or in the opposite direction. This has the disadvantage that the cooling effect is not particularly high. Furthermore, if the coolant is guided to the tool to be cooled, it will exit the cooling attachment near the workpiece to be machined and cool the workpiece.

[0004] The problem underlying the present invention is to improve the known cooling attachment for a working machine, the known device consisting of a working machine equipped with a cooling attachment according to the invention, the known method for operating said device and the method for manufacturing a cooling attachment, in such a way that the cooling of the working machine and the tools driven by the working machine is improved or made more efficient, while at the same time cooling of the workpiece to be machined is prevented as far as possible.

[0005] This problem is solved for the cooling attachment according to the invention by the subject matter of claim 1. The cooling attachment according to the invention is characterized in that a second cooling passage extending in the longitudinal direction of the housing is formed inside the housing for guiding the coolant from the free end of the housing shaft to at least one outlet opening also formed at the end of the housing near the work machine, and at least one connecting hole is provided between both cooling passages at the free end of the housing shaft for diverting the coolant from the first cooling passage to the second cooling passage.

[0006] The expression "at / in / in the free end" means "in / in / in the region of the free end".

[0007] The claimed double channel guidance and the connecting hole between the two channels, one of which serves as a feed line for the coolant to the tool to be cooled and the other as a return line for the coolant, advantageously allow the flow of coolant in the feed line to influence the flow of coolant in the return line, advantageously causing the flow of coolant in the return line to swirl, thereby improving the cooling effect of the flow on the tool, and in particular on the stamping pins, which in turn reduces wear on the tool and extends its service life or service life.

[0008] Tools, such as pins of a dot stamping machine, can heat up to several hundred degrees Celsius when working on a still-hot forged workpiece. Since the tools therefore require particularly intensive cooling, it is advantageous if the coolant, preferably swirled, which has an improved cooling effect due to the double ducting and deflection claimed in the present invention, is first directed to the tool to be cooled and only then to the machine to be cooled. By means of a second or (return) duct, the coolant is advantageously also directed next to the area of ​​the machine where the heated drive is installed, thus cooling the machine.

[0009] In addition to the vortex, the claimed deflection has the significant advantage that the coolant leaves the cooling attachment, apart from at least small leakage losses, in the area of ​​the tool to be cooled, where it is smoothly deflected into the return line, rather than undesirably cooling the machined workpiece. The return line, i.e., the second cooling channel, terminates in at least one outlet opening. According to the invention, this outlet opening is formed at the end of the housing near the work machine, i.e., opposite the free end, and thus is formed sufficiently far away from the possibly hot workpiece to be machined. In this way, the formation of the outlet opening there effectively prevents undesired cooling of the workpiece.

[0010] According to one embodiment of the invention, the advantageous swirling of the coolant is achieved in addition to the deflection by the fact that at least one connecting hole is preferably formed in the form of a plurality of annularly arranged nozzle openings, each oriented not approximately along the central longitudinal axis of the cooling attachment, but tangentially to the edge of a hole in the cooling attachment housing that leads the tool out of the cooling attachment. This generates a circular swirling flow of the coolant, thereby improving the cooling effect of the coolant. After absorbing heat from the tool, the thus heated coolant flows into the outlet opening within the second cooling channel.

[0011] According to another advantageous embodiment of the invention, in order to achieve the largest possible cross-section for the outlet opening, multiple outlet openings are distributed around the entire circumference of the housing. A large cross-section is particularly advantageous in combination with the conical design of at least one outlet opening, which allows the heated coolant to be drawn through the first and second cooling passages and discharged toward the outside of the cooling attachment. This conical design of the outlet openings advantageously eliminates the need for a blower to introduce or draw the coolant into the cooling passages through the inlet openings. The coolant flowing through the second cooling passage advantageously insulates the working machine, i.e., a dot stamping machine, against the radiant heat of the possibly still hot workpiece, particularly the forged part, and also protects the cooling attachment itself against the radiant heat due to this inward flow of the coolant.

[0012] The inventive design of the housing shaft, whose free end tapers conically towards the longitudinal axis of the housing, also provides the advantage that in this region the coolant is directed from the radially outer cooling passages through at least one connecting hole towards the longitudinal axis of the housing and thus towards the tool to be cooled emerging from the shaft of the work machine. This effect of the conical end of the housing shaft does not prevent the coolant from being directed tangentially towards the tool to be cooled, provided that the connecting holes are oriented accordingly.

[0013] The above-mentioned problem is further solved by an arrangement relating to a combination of a working machine and a cooling attachment according to the invention, as set forth in claim 10. The advantages of this arrangement are essentially the same as those mentioned above for the claimed cooling attachment.

[0014] According to an advantageous embodiment of the device, the cooling attachment according to the invention has a cavity for accommodating at least part of the working machine. This cavity is formed at the free end of the housing by a bore having a cross section substantially corresponding to the cross section of the tool inserted therein. This phrase means that the bore is only large enough to allow the tool to move through the bore without friction, but is not unnecessarily large. According to the invention, it is desirable to leave as small a gap as possible between the tool and the cooling attachment housing, thereby ensuring that as little coolant as possible can escape from the housing through this gap (see above: leakage losses). The escape of the coolant through the gap is ensured by the aforementioned circular spiral flow of the coolant and also by the suction generated by the large conical outlet opening in the upper region of the cooling attachment. Thus, the present invention ensures in various ways that the temperature of the workpiece being machined by the tool, for example a still hot forged part, is not undesirably reduced, but instead that the tool and the work machine that drives it are sufficiently cooled.

[0015] Finally, the object of the present invention is achieved by a method for operating the device according to the present invention as set forth in claim 14 and a method for manufacturing the cooling attachment according to claim 17. Due to its complex geometry, the cooling attachment according to the present invention is particularly advantageously manufactured by 3D printing. Geometrically, the cooling attachment is optimized for additive process / additive manufacturing constraints, so that it can be used directly from the printer. This means that no support structures are required, which must be removed afterward with considerable effort; the only mechanical post-processing required is a threaded hole for the air connection. Otherwise, the advantages of the method correspond to those described above for the claimed cooling attachment and the claimed device.

[0016] Advantageous configurations of the cooling attachment according to the invention, the device according to the invention and the method according to the invention for operating the device are the subject of the dependent claims.

[0017] The present invention is accompanied by four drawings. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective exterior view of a cooling attachment according to the present invention; [Figure 2] 1 is a longitudinal section of an apparatus according to the present invention; [Figure 3] 3 is an enlarged view of the free end of the device according to the invention of FIG. 2; [Figure 4] 1 is a cross-sectional view of an apparatus according to the present invention;

[0019] The present invention will be described in detail below by way of examples with reference to these drawings, in which the same technical elements are designated by the same reference numerals.

[0020] FIG. 1 shows a perspective exterior view of a cooling attachment 100 according to the present invention. The cooling attachment has a housing 110 having a shaft 112. The housing, including the housing shaft, is typically formed with a hollow chamber 160 for releasably receiving a work machine 200 (see FIG. 2), also having a shaft 210. The housing shaft 112 preferably tapers conically at its free end toward the longitudinal axis L of the cooling attachment. At an end 116 adjacent to the work machine, spaced apart from the free end 114, the housing 110 of the cooling attachment 100 has one inlet opening 122 and preferably multiple outlet openings 126 for a coolant for cooling the work machine 200, which may be received therein, and a rod-shaped tool 300 (see FIG. 2) extending from the shaft 210 and the housing shaft 112.

[0021] 2 shows an apparatus 400 according to the present invention. This apparatus 400 shows the cooling attachment 100 according to the present invention when it is attached to the work machine 200. In other words, the apparatus 400 represents the work machine 200 when the work machine 200 is housed in the hollow chamber 160 of the cooling attachment 100. In this case, the shaft 210 of the work machine 200 is also housed by the shaft 112 of the housing 110, and a tool 300 driven by the work machine 200 extends from a hole 162 formed in the free end 114 of the housing shaft 112. The tool 300 is driven in rotation by the work machine 200 or moved up and down in a hammer-like manner along the longitudinal axis L of the housing 110, which coincides with the longitudinal axis of the shaft 210 of the work machine.

[0022] As can be seen in the longitudinal section of the device 400 shown in FIG. 2, a first cooling passage 120 is formed in the outer wall of the housing 110 of the cooling attachment, extending in the longitudinal direction of the housing, for guiding coolant from an inlet opening 122 at the end 116 near the work machine to the free end 114 of the housing shaft, where it cools the rod-shaped tool 300. Arranged inside the free end of the housing shaft 112 is at least one connecting hole 150, which is preferably formed in the form of a plurality of annularly arranged nozzle openings, so that the incoming coolant is redirected into the second cooling passage 130 after impinging on the tool 300 to be cooled. The nozzle openings are preferably not oriented centrally toward the longitudinal axis L of the housing or tool 300, but rather tangentially to the edge of the hole 162 or to the tool 300, e.g., the pin of a dot stamping machine. The tangential orientation of the nozzle opening and thus the coolant flow results in a swirling motion of the coolant flow, advantageously resulting in improved cooling. The second cooling passage 130 returns the coolant from the free end 114 to the end 116 of the housing 110 near the work machine, where it can exit through the outlet opening 126. The outlet opening 126 is preferably conically shaped to draw the coolant through the inlet opening 122 and the first cooling passage 120 into the second cooling passage 130.

[0023] As can be seen in FIG. 2 , the first cooling passage 120 and the second cooling passage 130 are preferably each formed as annular passages and preferably extend coaxially with one another. While the first cooling passage 120 is formed entirely within the wall of the housing 110, the second cooling passage 130 is only partially defined by a wall as part of the housing 110, radially spaced from the longitudinal axis L of the housing 110. At its other, more radially inward portion, the second cooling passage of the cooling attachment opens toward the longitudinal axis L of the housing, i.e., is not defined by the housing 110 itself. Instead, the second cooling passage is defined there by the outer surface of the work machine 200, and in particular by the shaft 210 of the work machine 200 itself. That is, while the coolant flows within the second cooling passage 130 to the outlet opening 126, the coolant automatically flows along the work machine 200 and its shaft 210, thereby cooling these parts.

[0024] Figure 3 shows an enlarged view of the free end 114 of the housing shank shown in Figure 2. It can be seen how the tool 300 emerges from the free end 114 of the housing shank to machine the workpiece 500.

[0025] 3 and 4, the hole 162 has a cross section that substantially corresponds to the cross section of the tool 300 that passes through it. According to the invention, the gap between the tool 300 and the edge of the hole 162 is preferably made as small as possible so as to prevent as much as possible the escape of the coolant through this gap. In this way, according to the invention, in particular, unwanted cooling of the workpiece 500 to be machined is prevented.

[0026] 4 shows the introduction of the coolant through the inlet openings 122 into the first cooling passage 120, which is configured as an annular passage. As can be seen in the center of FIG. 4, the annularly arranged connecting holes or nozzle openings 150 at the free end 114 of the shank 112 of the housing 110 are not oriented exactly radially toward the longitudinal axis L of the housing, but are oriented tangentially toward the edge of the bore 162 or the edge of the workpiece 300, so that the desired swirl of the coolant is achieved there. In this regard, FIG. 4 shows a cross section of the cooling attachment according to the invention in a plane in the region of the end 116 of the housing near the work machine at the level of the inlet openings 122, as well as in a plane in the free end 114 of the housing shank 112. [Explanation of symbols]

[0027] 100 Cooling Attachment 110 Housing 112 Housing shaft 114 Free end of housing shaft 116 End of cooling attachment near work machine 120 first cooling passage 122 Inflow opening 126 Outlet opening 130 Second cooling passage 150 connection hole 160 Hollow chamber 162 Edge of hole 200 Work Machines 210 Shaft of work machine 300 Rod-shaped tools 400 equipment 500 workpiece L longitudinal axis of housing

Claims

1. A cooling attachment (100) for releasably attaching to a work machine (200), comprising: The working machine (200) has a shaft (210), in which a rod-shaped tool (300) is guided in a rotary or hammering manner, and extends from the shaft at its free end. The cooling attachment (100) includes a housing (110) with a housing shank (112) for releasably mounting on the shaft (210) of the work machine, the housing shank having a free end (114) that at least partially surrounds the free end of the shaft of the work machine and the tool (300) advanced therefrom; a first cooling passage (120) extending in the longitudinal direction of the housing is formed inside the housing for guiding a coolant from an inlet opening (122) provided at an end (116) of the housing (110) adjacent to the work machine to the free end of the housing shaft, where the coolant cools the rod-shaped tool (300); a second cooling passage (130) extending longitudinally of the housing (110) is formed within the housing for guiding the coolant from the free end (114) of the housing shaft to at least one outlet opening (126) also formed in the end (116) of the housing near the work machine; At least one connecting hole (150) is provided between both cooling passages (120, 130) at the free end of the housing shaft portion (112) for diverting the coolant from the first cooling passage to the second cooling passage. In the cooling attachment (100), The at least one connection hole (150) is oriented in a tangential direction of an edge of a hole provided in the housing (110) of the cooling attachment (100) that allows the rod-shaped tool (300) to advance toward the outside of the cooling attachment (100). A cooling attachment (100).

2. The cooling attachment (100) of claim 1, wherein the first cooling passage (120) and the second cooling passage (130) are each formed as an annular passage.

3. 3. The cooling attachment (100) according to claim 1 or 2, wherein the first cooling passage (120) is formed inside the outer wall of the housing (110), and the second cooling passage (130) is formed inside the housing (110) at a position radially more inward than the first cooling passage (120).

4. 4. The cooling attachment (100) of claim 3, wherein the second cooling passage (130) is only partially defined by a wall as part of the housing, radially spaced from the longitudinal axis (L) of the housing, and opens toward the longitudinal axis (L) of the housing at another portion located more radially inward.

5. 3. The cooling attachment (100) according to claim 1 or 2, characterized in that the cooling attachment has a hollow chamber (160) for accommodating at least a portion of the work machine (200) and for passing the tool (300) at the free end (114) of the housing shaft portion (112), and the at least one connection hole (150) is formed in a direction tangential to an edge of the hollow chamber from an outer first annular passage.

6. 3. The cooling attachment (100) according to claim 1 or 2, characterized in that a plurality of said outlet openings (126) are distributed around the entire circumference of said housing (110).

7. 3. The cooling attachment (100) according to claim 1 or 2, characterized in that the at least one outlet opening (126) is conically shaped.

8. 3. The cooling attachment (100) according to claim 1 or 2, characterized in that the free end of the housing shaft (112) is conically tapered towards the longitudinal axis (L) of the housing.

9. An apparatus (400) comprising: A work machine (200) having a shaft (210), in which a rod-shaped tool (300) is guided in a rotary or hammering manner within the shaft (210), the rod-shaped tool extending from a free end of the shaft (210) of the work machine; a cooling attachment (100) having a housing (110) with a housing shank (112) for releasably mounting to the shaft of the work machine (200), the housing shank (112) having a free end (114) for at least partially surrounding the free end of the shaft (210) of the work machine and the tool (300) advanced therefrom; An apparatus (400) having 2. Apparatus (400) characterized in that the cooling attachment (100) is formed according to claim 1.

10. The apparatus (400) of claim 9, wherein at least a portion of the work machine (200) is housed within a hollow chamber (160) of the cooling attachment (100).

11. The device (400) according to claim 10, characterized in that the hollow space (160) is formed at the free end of the housing shank by a hole (162) having a cross section substantially corresponding to the cross section of the tool (300) advanced therein.

12. 12. The device (400) of claim 11, wherein the connecting hole (150) between both cooling passages (120, 130) at the free end (114) of the housing shaft is oriented in a tangential direction of the tool (300) extending from the shaft (210) of the work machine (200).

13. 11. The device (400) according to claim 9 or 10, characterized in that the radially inner portion of the wall of the second cooling passage (130) is formed by the outer wall of the work machine (200) and the tool (300) as long as the tool (300) extends from the shaft portion (210) of the work machine.

14. 10. The method of operating the device (400) of claim 9, comprising: - introducing said refrigerant into said first cooling passage (120) through said inlet opening (122) in said housing (110) of said cooling attachment (100); Including, the coolant is guided through the first cooling passage towards the tool (300) emerging from the shaft (210) of the work machine, where it is diverted into the second cooling passage (130) to cool the tool and the work machine (200), and from the second cooling passage (130) it flows out through the at least one outlet opening (126) provided in the end (116) of the housing (110) on the work machine side.

15. The method of claim 14, wherein the coolant flows turbulently within the second cooling passage (130) during return.

16. 16. The method of claim 14 or 15, characterized in that the coolant is drawn in at least the second cooling passage (130) towards the at least one conical outlet opening (126).

17. A method for manufacturing a cooling attachment (100) according to claim 1 or 2, comprising: 3D printing the cooling attachment.

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