DE20005442U1 - Tool support bezel and deep drilling unit equipped with it - Google Patents

Description

Dipl.-Chem. Dr. Michael Ruff Dipl.-lng. Joachim Beier Dipl.-Phys. Jürgen Schöndorf Dipl.-Chem. Dr. Thomas Mütschele

Ruff, Beier and Partner · PO Box 104036 · D-70035 Stuttgart European Patent and Trade Mark Attorneys

Partnership Register Stuttgart PR 43

Applicant: Nagel Maschinen- und Postfach (POB) 10 40 36, D-70035 Stuttgart

Werkzeugfabrik GmbH Willy-Brandt-Str. 28, D-70173 Stuttgart

Oberboihingerstraße 60 Telephone+49 (0)711-22 2976-0

Fax+49 (0)711-22 29 76-76

__,.”” _-T ... . e-mail: info@RBuP.DE

72 622 Nurtmgen

Dresdner Bank (bank code 600 800 00) Account 9 011341 Landesgirokasse (bank code 600501 01) Account 2530413

A 34 85 0 Postbank Stuttgart (bank code 60010070) account 42930-708

VAT number: DE 147528073

27 March 2000 JB/Mu/sc

Description

Tool support steady rest and deep drilling unit equipped with it

The invention relates to a tool support rest according to the preamble of claim 1 and to a deep drilling unit equipped with at least one tool support rest.

Deep drilling is a modern, economical machining process that is not only used to produce long or deep holes, but also for shorter holes with higher accuracy, i.e. for precision drilling. The special feature of deep drilling is the pressure flushing with a liquid medium, usually referred to as coolant, which, in conjunction with specially designed deep drilling tools that have a coolant supply and a chip return system, enables the chips created during machining to be transported back out of the hole, the cutting and guide strips of the deep drilling tool to be lubricated and the cutting heat to be dissipated.

For trouble-free operation, it is advisable to collect the coolant carrying the chips from the borehole in a chip collecting container and to transport it away from the

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The coolant can be returned to the processing location after filtering if necessary.

When deep drilling holes with a greater hole depth than the hole diameter, for example holes with a hole depth more than forty times the hole diameter, there is a risk that the deep drilling tools will swing open, buckle and possibly break off during drilling. This risk is particularly increased with single-lip deep drilling tools due to their asymmetrical design, which can lead to an imbalance.

In addition, high spindle speeds of several thousand rpm, for example up to around 20,000 rpm, are sometimes used. The axial load on the tool caused by the feed itself also contributes to this risk. Economical work therefore becomes more difficult, especially with small bore diameters, as the risk of tool breakage increases.

To counteract this danger, so-called tool support rests are used to support the tool, 0 for example to prevent the described oscillation. A tool support rest has a rest body with at least one tool guide opening provided therein, which runs through in the guide direction, for guiding a deep drilling tool that can be guided through the tool guide opening in the guide direction. The diameter of the guide opening is suitably adapted to the tool diameter in the section provided for guidance so that the tool fits through the guide opening essentially without play, so that vibrations transverse to the guide direction are largely avoided 0 or can be limited to small amplitudes.

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For larger drilling diameters, the tool length often does not play a decisive role. In such cases, steady rests are usually arranged between the so-called drill bush carrier and the drilling spindle, which has a tool holder for the deep drilling tool. Depending on the drilling depth, there can be one or more steady rests. These are then pushed together one after the other towards the drill bush carrier during the drilling process. They mean tool length loss, since the tool has to be made longer by the amount of the axial steady rest width than when drilling without steady rests. For smaller drilling diameters, this use of conventional steady rests can be disadvantageous, since the deep drilling tools for smaller hole diameters should be designed as short as possible for reasons of stability.

The invention is based on the object of creating a tool support lunette, the use of which reduces or prevents the risk of tool breakage even with tools for smaller drilling diameters.

To solve this problem, the invention proposes a tool support rest with the features of claim 1. Preferred developments are specified in the dependent claims. The wording of all claims is incorporated into the content of the description by reference.

A tool support lunette according to the invention of the type mentioned at the beginning is characterized in that it can be moved away from the area of the deep drilling tool without axial relative displacement between the tool support lunette and the deep drilling tool, while releasing the deep drilling tool from the guide opening. This makes it possible, for example, to move the tool support lunette, also referred to below as the lunette, away from the tool area as soon as

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of the tool feed, the tool holder on the drilling spindle has moved so close to the steady rest that, due to the short free length between the steady rest and the tool holder, no support is required. The further tool feed can then take place in such a way that the tool holder can be pushed forward into the area where the steady rest was previously located. This can be moved to the side, i.e. across or perpendicular to the guide direction, so far away that it does not form an interference contour for the tool feed. Steady rests according to the invention therefore clear the feed path when they are no longer required.

The invention makes it possible in particular for the tool support rest to be arranged or able to be arranged essentially completely within a chip collecting space of a chip collecting container of the deep drilling unit that is essentially sealed off from the outside. As mentioned above, for small drilling diameters, the shortest possible deep drilling tools should be used. For this reason, the closed drill bush carrier used for larger drilling diameters is often dispensed with, so that a space is formed between the drill bush, i.e. the tool guide closest to the workpiece, and the drill spindle, in whose tool holder the deep drilling tool is clamped. The drilling chips flowing back are thrown into this space at high speed, since lubricant pressures of up to 200 bar are usually used. This space between the drill bush and the drill spindle is expediently enclosed with a chip collecting container of variable length, in particular a telescopic chip box of the type shown in DE 196 13 443.

0 In this space between the drill bush and the tool holder, tool support lunettes according to the invention can be implemented. Since tool support lunettes according to the invention are made of the

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tool area, it is also possible to plunge the shaft reinforcement of the tool holder into the drill bushing holder that carries the drill bushing during the tool feed. This enables the use of the shortest possible tools, since their length between the tool tip and the shaft reinforcement only needs to be approximately the axial length of the drill bushing longer than the desired drilling depth.

In a further development explained in more detail in connection with the embodiments, the tool support steady rest is arranged or can be arranged in the area of the drill bushing carrier of the deep drilling unit, i.e. in the area of a tool guide device facing the workpiece in the immediate axial proximity to the workpiece. In particular, the drill bushing carrier can also serve as a carrier for the steady rest, which can therefore be an integral part of the drill bushing carrier. As a result, the steady rest can be arranged in the axial direction particularly close to the drill bushing in a movement-stable manner, which enables the tool to be supported by the steady rest until immediately before the end of the feed process.

0 The invention can be implemented in various ways that can be selected or combined depending on the application. In a further development, the steady rest body has a transverse opening that runs transversely to the guide direction and leads to the guide opening, the clear width of which is adapted to the cross section of the deep drilling tool in such a way that the deep drilling tool can be guided through the transverse opening in at least one of its rotational positions, i.e. can be inserted into the guide opening or removed from it. The steady rest body can be designed, for example, as a fork-shaped support shoe, with the guide opening typically only being closed over a circumference of approx. 18 0° and otherwise being open to form the transverse opening.

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In this case, the movement of the steady rest body away from the tool area can be achieved, for example, by mounting the steady rest body so that it can be moved linearly across the guide direction. It is also possible to mount the steady rest body so that it can pivot about a pivot axis that preferably runs parallel to the guide direction, in which case the side opening can be curved so that its radius of curvature coincides with the pivot axis.

If, with such support rests that are open on one side, there is a risk that the tool guidance in the direction of the transverse opening is not sufficient, several such support shoes with different opening directions can of course be provided one behind the other, possibly at a short axial distance, in order to provide a guide that essentially encloses the entire circumference of the tool.

It is also possible for the steady rest body to have several, in particular two, steady rest elements forming the tool guide opening, which are movable relative to one another in such a way that the guide opening can be opened by relative movement of the steady rest elements to release the deep drilling tool from the guide opening or closed to accommodate the deep drilling tool in the guide opening. Such open embodiments make it possible for the guide opening to be essentially closed in the circumferential direction and therefore enable the tool to be guided on all sides. The guide opening can then be formed in particular by two half-shells or recesses, each enclosing approximately 18° and located at the same axial height.

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Here too, there are various implementation options depending on the installation environment and use. For example, the steady rest body can be hinged open by pivoting at least one of the steady rest elements to open the guide opening. It is also possible for it to be pulled apart by linear displacement of at least one of the steady rest elements to open the guide opening. Two steady rest elements are expediently arranged symmetrically to a plane containing the tool's longitudinal axis and can be moved symmetrically towards or away from the tool.

The tool support rest can be actuated manually to move it away from the tool. Preferably, however, the tool support rest is assigned an automatic actuating device for moving the tool support rest away from the area of the deep drilling tool, whereby this actuating device can preferably be controlled in a path-related or path-dependent manner, so that an automatic removal or evasive movement of the tool support rest can take place automatically when the drilling spindle approaches the area of the rest to a certain extent. The drive of the actuating device is preferably mechanical, pneumatic or hydraulic, but can also be electrical if necessary. The coupling between the drive and the rest or rest element can be carried out, for example, via mechanical actuating systems, spindles, cam systems, push rods and/or the like.

In order to ensure trouble-free operation, a further development provides that the tool support rest is assigned an automatic cleaning device to keep the tool support rest clean. This can include at least one spray nozzle for rinsing fluid directed at the tool support rest. Such cleaning devices are particularly advantageous for support rests that are in direct

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are arranged in close proximity to the drill bushing and/or in a chip collection container, which ensures that chips hitting the steady rest at high speed do not clog the system, which in turn could lead to tool breakage or other malfunctions.

Although tool rests according to the invention are particularly advantageously arranged or can be arranged inside a chip collection container, and in particular inside a drill bushing carrier, this steady rest system can also be used outside the drill bushing carrier instead of the known systems in order to enable the desired general shortening of the deep drilling tools. Of course, designs are possible for both single-spindle and multi-spindle machines, whereby a tool support steady rest can have one or more tool guide openings arranged one above the other, for example.

These and other features emerge not only from the claims but also from the description and the drawings, whereby the individual features can be implemented individually or in combination in the form of sub-combinations in an embodiment of the invention and in other fields and can represent advantageous embodiments.

Embodiments of the invention are shown in the drawings and are explained in more detail below. In the drawings:

Fig. 1 is a vertical longitudinal section through a preferred embodiment of a deep drilling unit with an embodiment attached to a drill bush carrier.

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shape of a tool support rest according to the invention;

Fig. 2 and 3 two in the manner of a one-sided open

Support shoe formed, moved linearly in the transverse direction from the tool area

bare tool support lunettes;

Fig. 4 a one-sided open

Swiveling tool support rest designed as a support shoe,

Fig. 5 an embodiment of a hinged

Tool support rest and

Fig. 6 an embodiment of a disassembled

pull-out tool support rest.

The deep drilling unit 1 shown in Fig. 1 in a vertical section is clamped on a clamping table (not shown) on which a clamping element (not shown) is also arranged, which holds the workpiece 2. The flat face of the workpiece 2 facing the deep drilling unit rests on a tool guide device 4 of the deep drilling unit. The tool guide device 4 comprises a solid drill bush carrier 5 with an axial through-opening in which a drill bush holder 6 is seated, which carries a drill bush 7 on its side facing the workpiece. The workpiece 2 rests with its front side directly on the drill bush which projects beyond the front side of the drill bush carrier facing the workpiece. The drill bush 7, with its axial through-opening, forms the tool guide of the deep drilling unit closest to the workpiece.

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On the side of the drill bushing carrier facing away from the workpiece, a headstock with a drill spindle 10 that can rotate about a horizontal spindle axis is clamped on the clamping table at an axial distance from the latter, the end of which facing the workpiece has a tool holder 11 for clamping a deep drilling tool 12. The deep drilling tool has a tubular shaft 13, at one end of which a shaft reinforcement 14 serving as a clamping sleeve is arranged for clamping the tool in the drill spindle. At the opposite end of the shaft, a drill head 15 is attached, which contains at least one cutting edge. The hollow tool shaft has at least one longitudinal channel 16 running parallel to the tool's longitudinal axis 18, through which flushing and cooling liquid introduced in the area of the tool holder 11 is conveyed under pressure to the front side of the drill head 15, where it exits the drill head and flushes the drilling chips out of the hole. In order to enable the drilling chips to be flushed out of the bore, both the drill head and the shaft contain a groove 0 or bead 17 running in the axial direction, through which the flushed-out material is discharged to the side of the drill bush carrier facing away from the workpiece, i.e. into the space between the drill bush and the drill spindle.

This space is covered by a telescopic cover 19. This, together with the drill bushing carrier serving as the front wall, a rear wall supporting the drill spindle and side walls (not shown), forms a chip collecting container 20 which is essentially splash-tight against the outside. This can be constructed in detail like the chip collecting container disclosed in DE 196 13 443, the features of which are incorporated into the content of this application by reference. When the tool is fed towards the workpiece, the rear wall moves towards the drill bushing carrier, whereby the length of the chip collecting container decreases.

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The tool 12 is supported in the area between its clamping on the drilling spindle 10 and the guide formed by the drilling bushing 7 and close to the workpiece by means of a tool support lunette 25 in the transverse direction, in particular perpendicular to the axis of rotation 18 of the tool. This serves to prevent the deep drilling tool from swinging up, buckling and possibly breaking off during drilling due to its movement in the transverse direction. A corresponding vibration antinode between the fixing points on the tool holder 11 and the drilling bushing 7, which act as "nodes", is shown in a greatly exaggerated dash-dotted line. This risk of swinging up occurs with the single-lip deep drilling tools shown, among other things, due to their asymmetrical structure, which leads to an imbalance, and the typically very high spindle speeds, as well as due to the axial load on the tool during feed. The deep drilling tool shown schematically, for example, has an effective diameter of less than 2 mm and is designed for a drilling depth at least forty times greater. Typical spindle speeds are in the range up to approx. 20,000 rpm.

The steady rest 25 shown in Fig. 2 in an axial view is attached directly to the drill bushing carrier 5 and protrudes from above into the chip collection container. It has a steady rest body in the form of a support shoe 26 in which a tool guide opening 27 is formed that runs through the guide direction or the tool longitudinal direction 18. This is dimensioned in such a way that it encloses the circumference of the tool 12 over a circumferential length of approx. 180° with a small radial distance. The guide opening merges downwards or perpendicular to the guide direction 18 into a transverse opening 28, which widens outwards in the shape of a mouth. The transverse opening has a clear width corresponding to the diameter of the guide opening, which corresponds to the transverse

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section of the deep drilling tool is adapted so that the steady rest can be pulled off the tool transversely to the longitudinal direction of the tool in order to be removed from the area of the tool. In the embodiment shown, this vertical adjustment movement (arrow 29) for applying the tool steady rest (by vertical movement downwards) or for pulling the tool steady rest out of the tool area (by moving the tool steady rest upwards) is carried out automatically with the aid of a hydraulic or pneumatic drive (not shown).

From Fig. 3 and 4 it can be seen that such generally fork-shaped or mouth-like steady rest bodies can also be moved out of the area of the tool or placed against the tool in another expedient manner without axial movement parallel to the tool axis. For this purpose, Fig. 3 shows a horizontally movable support shoe 30 which is essentially identical to the support shoe 25 and whose transverse opening is aligned horizontally in accordance with the alignment of the travel path.

In the steady rest 35 shown in Fig. 4, however, the steady rest body 36 designed as a support shoe is pivotably mounted, for example, on the drill bushing carrier, about a pivot axis 37 running parallel to the guide direction 18. Here too, the guide opening 38 encloses a circumferential angle of the tool of 180°.

Fig. 5 shows an embodiment of a hinged steady rest 40. The steady rest body is essentially formed by two steady rest elements 41, 42 in the form of swivel arms which are pivotably mounted on a common carrier, for example the drill bush carrier 5. These are mirror-symmetrical to a

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Vertical plane 43 and can be pivoted about pivot axes 44 that are parallel to the axis and aligned parallel to the guide direction 18. In this hinged steady rest, the steady rest elements, which are arranged in mirror symmetry and may be identical to one another, with semicircular recesses directed towards one another, enclose a tool guide opening 45 in the closed or folded configuration shown, which is essentially closed in the circumferential direction and can be opened by pivoting the steady rest elements. The guide opening, which essentially completely encloses the tool, ensures particularly reliable guidance in all radial directions.

Although the inside of the tool guide opening facing the workpiece can be made of the same material as the steady rest body or the steady rest element, in the embodiment according to Fig. 5, separate, essentially half-ring-shaped support bushing elements 46 are attached to the steady rest elements 41, 42 to form the tool guide opening. These can be, for example, rings or half-rings made of hard metal, ceramic, a plastic or another suitable soft or hard material.

In the extendible steady rest 50 shown in Fig. 6, two steady rest elements 51, 52 are also provided, which may be identically constructed but are arranged mirror-symmetrically to the vertical plane and which, like a two-part sliding door, can be brought into contact with the deep drilling tool enclosed between them by horizontal linear movement or can be removed from its area by counter-movement. The advantage of an essentially completely enclosed tool guide opening can also be realized in this embodiment. Such embodiments are

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Particularly suitable for multi-spindle machines, for example by providing two or more guide openings one above the other that can be opened or closed at the same time.

When designing a deep drilling device, depending on the intended application, available installation space or other technical requirements, one can choose between these different embodiments or similar embodiments within the scope of the claims, or they can be combined. All embodiments advantageously enable one or more tool support rests to be implemented in the space between the drill bush 7 and the tool holder 11. Thanks to the possibility of moving the tool rest transversely, in particular perpendicular to the tool's longitudinal direction, away from the area of the tool, it is possible to work with shorter tools compared to the prior art, which avoids the risk of tool breakage and other problems associated with the swinging of deep drilling tools. In particular, for example, in the arrangement shown in Fig. 1, the steady rest can be immersed in the drill bush holder 5 with the shaft reinforcement 14 after it has been removed from the tool area, because the steady rest can be moved out of the tool area in the transverse direction. This is not possible with normal circumferentially closed or non-opening steady rests, so that even if their axial extension is very small, a significant axial section of the tool shank near the shank extension cannot be used to penetrate the hole. Therefore, when using conventional support strips, the tools must be comparatively longer in order to achieve the same drilling depth.

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Steady rest systems according to the invention can also be used advantageously outside the drill bush carrier or outside a chip box instead of the known systems, since in the manner mentioned they contribute to the fact that comparatively shorter deep drilling tools can be used.

Claims (13)

1. Tool support rest with a rest body and at least one tool guide opening provided in the rest body for guiding a deep drilling tool that can be guided through the tool guide opening in a guide direction; characterized in that the tool support rest (25; 30; 35; 40; 50) can be moved away from the area of the deep drilling tool without axial relative displacement between the tool support rest and the deep drilling tool, releasing the deep drilling tool (12) from the guide opening (27; 38; 45; 53). 2. Tool support rest according to claim 1, characterized in that it is arranged or can be arranged at least with the region of the guide opening (27) within a chip collecting space of a chip collecting container (20) of a deep drilling unit (1) that can be closed essentially to the outside, in particular in a chip collecting container with variable length. 3. Tool support rest according to claim 1 or 2, characterized in that it is arranged or can be arranged in the region of a tool guide device (4) of the deep drilling unit facing the workpiece, wherein preferably a drill bushing carrier (5) serves as a carrier for the tool support rest (25; 30; 35; 40; 50). 4. Tool support steady rest according to one of the preceding claims, characterized in that the steady rest body (26; 36) has a transverse opening (28; 39) running transversely to the guide direction (18) and leading to the guide opening (27; 38), the clear width of which is adapted to the cross section of the deep drilling tool in such a way that the deep drilling tool can be guided through the transverse opening in the transverse direction. 5. Tool support rest according to claim 4, characterized in that the rest body (26) is mounted so as to be linearly displaceable transversely to the guide direction (18). 6. Tool support rest according to claim 4 or 5, characterized in that the rest body (36) is pivotally mounted about a pivot axis (37) preferably running parallel to the guide direction (18). 7. Tool support rest according to one of the preceding claims, characterized in that the rest body has several, in particular two, rest elements (41, 42; 51, 52) forming the tool guide opening (45; 53), which are movable relative to one another in such a way that the guide opening can be opened by relative movement of the rest elements to release the deep drilling tool (12) or closed to accommodate the deep drilling tool in the guide opening. 8. Tool support rest according to claim 7, characterized in that it can be folded open to open the guide opening (45) by pivoting at least one of the rest elements (41, 42). 9. Tool support rest according to one of claims 7 or 8, characterized in that it can be pulled apart to open the guide opening under linear displacement of at least one of the rest elements (50, 51). 10. Tool support steady rest according to one of the preceding claims, characterized in that it is assigned an automatic, preferably mechanically, hydraulically or pneumatically actuated actuating device for moving the tool steady rest away from the area of the deep drilling tool (12), wherein the actuating device is preferably controllable as a function of the path. 11. Tool support rest according to one of the preceding claims, characterized in that it is assigned an automatic cleaning device for keeping the tool support rest clean, in particular with at least one spray nozzle directed at the tool support rest. 12. Tool support rest according to one of the preceding claims, characterized in that to form the guide opening on the rest body at least one preferably substantially semicircular support element (46) is arranged, which consists of a material promoting the guide, in particular of hard metal, ceramic or plastic. 13. Deep drilling unit with at least one tool support rest according to one of claims 1 to 12.