DE20310828U1 - Motorised lathe for insides of tubes, includes forced guide for support device for opposite end of drill rod to workpiece chuck - Google Patents

Abstract

A support device (31) is provided on the second end (22) of the drill rod (20) extending away from the chuck (25). The support device can be moved along a guide track (32) in an axial direction, the guide track being present in a forced guide device securable directly to the machine bench (12). The lathe (10) has a rotary chuck for the workpiece (26) and includes a sleigh (18) movable in an axial direction along the machine bench for holding a drill rod with a tool (23), preferably holding the drill rod in its middle region. The first end (21) of the drill rod extends towards the chuck in an axial direction. An independent claim is also included for the forced guide device, comprising a part which is releasably securable to the machine bench via fasteners.

Description

The invention relates firstly to a device for the internal machining of tubular workpieces according to the preamble of claim 1.

Such a device has become known through obvious prior use. The known device is used to machine tubular workpieces, in particular stainless steel cast, gray cast or aluminum cast pipes produced using the permanent mold casting process, from their interior. The pipes of different diameters and different axial lengths used, for example, in seawater treatment plants, power plants or plants in the chemical or pharmaceutical industry require a high degree of dimensional accuracy of the pipe's inner diameter or wall thickness. After the pipe has been manufactured, it almost inevitably requires post-processing using the known device.

Postbank Essen I .

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(Bank code 330 600 98) 301 891 024 (Bank code 330 400 01) 4 034 823 Tax no.

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The known device is also generally referred to as a lathe, in particular as a heavy lathe, and has a rotationally driven chuck for the workpiece. The workpiece is inserted into a spindle bore provided for this purpose in a so-called spindle stock and is secured there at one end. The chuck can be driven in rotation so that the clamped workpiece can be rotated around its central longitudinal axis with an adjustable rotation speed if necessary.

The known device has a machine bed on which a slide is arranged so as to be axially movable. The slide is typically designed as a cross slide and can be moved both in the axial direction and in the transverse direction. The cross slide is assigned a support on which a boring bar is held. The boring bar protrudes from the slide or the support in the axial direction both towards the chuck and in the opposite direction.

The boring bar has a tool at its first end, directed towards the chuck, with which the tubular workpiece is machined from the inside. The boring bar of the previously known device has an axial length that ensures that the tool arranged at the first free end of the boring bar can penetrate completely into the interior of the workpiece to be machined. In this regard, it should be noted that the tubular workpiece is continuously machined from its free end until the tool reaches the clamped end of the workpiece, with the carriage, the boring bar and the tool being connected to one another in a uniform movement and being continuously moved towards the chuck.

In this context, it should be noted that the invention includes both devices in which the carriage is moved manually

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as well as devices in which the movement of the carriage is automatic and controlled.

A previously known device is known, for example, from the catalogue VoIz 2000 of the Maschinenhandelsgesellschaft Volz-Witten, pages 16 to 17.

The known device has a machine bed of a predetermined length, for example between 5,000 and 6,000 mm. If workpieces with a particularly large axial length are to be machined, correspondingly long boring bars must be provided. The torques that arise due to the large lever arm lengths are problematic, as they can lead to strong vibrations and only allow workpieces up to a maximum axial length to be machined. In order to be able to machine even longer workpieces and thus reduce the changeover times of the devices, it is known to not only clamp the boring bar to the support of the slide, but also to allow the boring bar to protrude with its second end beyond the support or slide. In this way, the boring bar is clamped essentially centrally in the area of the slide, so that a lateral or vertical movement of the first free end of the boring bar results in a corresponding counter movement of the second free end of the boring bar. The clamping of the boring bar to the slide thus essentially corresponds to a rocker arrangement.

Through prior public use, it has also become known that the second end of the drill rod can be stabilized by a mass element attached to it. The mass element can be, for example, a metal-filled bag or the like, which is attached in a suitable manner to the second end of the drill rod. Due to the mass element, a vibration-induced

Heinz-Dietmar Sieper *: ',

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The free movement of the first free end of the boring bar, on which the tool is arranged, is dampened. The first free end is prevented from moving to a certain extent due to the mass element attached to the other end of the boring bar. Vibrations are therefore suppressed, which leads to significantly improved work results and higher work speeds.

The invention is based on the task of

known, merely provisional device of the prior art, to develop the device according to the preamble of claim 1 in such a way that an improved processing

of the workpiece.

The invention solves this problem with the features of claim 1, in particular with those of the characterizing part, and is accordingly characterized in that a support device is provided for the second end of the boring bar, which is displaceable in the axial direction along a guide track, wherein the guide track is provided by a separate positive guide device that can be at least indirectly fastened to the machine bed.

The principle of the invention therefore essentially consists in providing a support device for the second end of the boring bar, which makes it possible to fix the second end of the boring bar so that it only has a single degree of freedom, namely the possibility of movement in the axial direction. Movement of the second boring bar end in both the vertical and lateral (=horizontal) direction can be excluded if the support device at least partially encompasses the second end of the boring bar. The second end of the boring bar is thus fixed relative to the machine bed up to the degree of freedom of the axial displacement, which at the same time also stabilizes the first end of the boring bar.

Heinz Dietmar Sieper *· ···.,· ; ,·

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According to the invention, the support device can be displaced in

Axial direction is provided in such a way that when the movable carriage is displaced in the axial direction, the support device to which the second end of the boring bar is attached is also displaced and is thus pulled behind the carriage.

In order to increase the working precision of the device, a special guideway is provided for the support device, along which the support device can be moved. The guideway is provided by a positive guide device that is arranged on a separate component. The positive guide device, and thus the component, can be attached to the machine bed in an at least indirectly detachable manner.

While a conventional machine bed typically has a groove-shaped receiving tray that is essentially axially elongated and is used to attach steady rests, as well as several contact and prism surfaces for the slide that are essentially arranged on the top of the machine bed, a new guide that is independent of the machine bed is made available by providing a separate positive guide device with its own guideway. This enables an existing device to be retrofitted and the positive guide device to be attached to different machine beds.

The invention enables the support device to be used even on heavily soiled or dirty machine beds, whose contact and prism surfaces would provide a guideway that is unsuitable for a support device. This makes it possible to create a device that is simple to manufacture in terms of design and construction, and thus inexpensive, which enables improved machining of the workpiece.

Heinz-Dietmar Sieper

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According to an advantageous embodiment of the invention, the component can be attached to the machine bed in a variety of different attachment positions spaced apart in the axial direction. This also makes it possible to attach the component in a position in which it protrudes beyond the machine bed in the opposite direction. This extends the machine bed in a particularly simple manner, so that workpieces with a significantly greater axial length can also be machined on the existing device with the axially limited machine bed.

According to a further advantageous embodiment of the invention, the component attached to the machine bed with the positive guide device is arranged essentially within the contour of the receiving trough. This embodiment of the invention enables a particularly simple attachment of the component to the machine bed on the existing holding or counter-holding surfaces provided for the attachment of steady rests.

According to another particularly advantageous embodiment of the invention, the positive guide device attached to the machine bed and/or the component attached to the machine bed can be traversed by the carriage. In this way, the invention can be used particularly flexibly.

According to a further aspect, the invention relates to a positive guide device for a support device of a device having a machine bed.

Such a positive guidance device for steady rests, which support a workpiece, for example, is known.

The invention is based on the object of developing the known forced guidance device in such a way that a processing

·

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machining of axially elongated, tubular workpieces is possible in an advantageous manner.

The invention solves this problem with the features of claim 14, in particular with those of the characterizing part, and is accordingly characterized in that the positive guide device is arranged on a component separate from the machine bed, and that the component has fastening means for detachable fastening to the machine bed.

Further advantages of the invention emerge from the uncited subclaims and from the following description of an embodiment shown in the figures. In the drawings:

Fig. 1 shows a schematic plan view of an embodiment of the device according to the invention,

Fig. 2 shows a schematic view of the device of Fig. 1 according to arrow II in Fig. 1,

Fig. 3 shows schematically, in partial section, the support device and the machine bed approximately along section line HI-III in Fig. 1, whereby the boring bar is omitted for the sake of clarity, and

Fig. 4 shows the embodiment according to Fig. 1 with an axially longer workpiece, an axially longer boring bar and a component located in a fastening position protruding beyond the machine bed.
30

The device designated as a whole with 10 in the figures will first be described with reference to Figs. 1 to 3:

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The device 10 has a base 11, i.e. a frame that supports the entire device 10 and is best seen in Fig. 2. The base 11 supports a machine bed 12, which is typically made of hardened and ground steel. The machine bed is explained as follows with reference to Fig. 3, which shows a schematic sectional view of the machine bed 12:

The machine bed 12 has a bottom wall area 14 which, although not shown in Fig. 3, rests on the base 11 of the device and is attached to it. A first side wall area 13a and a second side wall area 13b extend from the bottom wall areas 14, both of which have a large number of dimensionally accurate contact or guide and prism surfaces. The machine bed 12 according to Fig. 3 has prism surfaces 16a, 16b, 16c, 16d and top contact surfaces 17a, 17b, 17c, 17d. Lateral contact surfaces 17e, 17f, 17g and 17h are also provided. The essentially U-shaped cross-section of the machine bed 12 results in a receiving trough 15. The cross-section of the machine bed 12 is unchanged over the entire axial length I of the machine bed 12.

A carriage 18 can be moved on the machine bed 12 in the axial direction of the machine bed 12, i.e. along the double arrow x. The carriage uses some of the aforementioned prisms or contact surfaces 16a, 16b, 16c, 16d, 17a, 17b, 17c, 17d, 17e, 17f, 17g, 17h as guide surfaces. The carriage 18 can be adjusted in the axial direction x manually, but preferably automatically, i.e. controlled by a control device (not shown).

As can be seen from Fig. 2, a support 19 is arranged on the carriage 18, which provides a holder 46 for a boring bar 20. The holder 46 is arranged relative to the carriage 18 preferably along the direction of the double arrow y, i.e. transversely to the axial direction x, and also

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Preferably, it can also be displaced in the vertical direction ζ. Such carriage arrangements, comprising a carriage 18, a support 19 and a holder 46, are known and are usually referred to as cross slides.
5

The boring bar 20 has a first end 21, which is on the left with respect to Figs. 1 and 2, and a second end 22, which is on the right with respect to Figs. 1 and 2. A tool 23 is arranged at the first end 21, which is used for the internal machining of a workpiece 26.

The boring bar is firmly attached in the holder 46 and can thus be moved with the carriage 18. It should be noted that the boring bar 20 is preferably clamped approximately centrally in the holder 46.

The device 10 also comprises a headstock 24 with a chuck 25 for the workpiece 26 at its left end with respect to Figs. 1 and 2. The workpiece is a pipe, typically a cast metal pipe, which has a circular cross-section and is to be machined from its interior 30 with the tool 23. In particular, a uniform, constant wall thickness w of the workpiece 26 should be achieved. If machining of the workpiece 26 from its outside should also be necessary, this will not be explained further here.

The workpiece 26 is held with its first end 27 in the chuck 25 and is rotated about its central longitudinal axis by a rotary drive (not shown in detail), e.g. by an indicated shaft, so that the workpiece 26 rotates about the axis of rotation D. The workpiece 26 is held in a steady rest 29 with a second end 28, the non-clamped free end. A steady rest essentially refers to a support device which at least partially encompasses the workpiece 26 on its outer surface and has a

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not shown bracket which is attached to the machine bed 12.

To machine the workpiece 26, the tool 23 is gradually moved towards the workpiece 26, finally introduced into its interior 30 and moved with constant rotation of the workpiece 26 to its first end 27. For this purpose, the carriage 18 moves, preferably at a constant speed along the direction of the double arrow &khgr; towards the headstock 24.

In the case of particularly axially elongated workpieces 26, e.g. pipes with a length of more than 1500 mm, the drilling rods 20 must also be designed to be correspondingly long so that the tool 23 can completely immerse itself in the workpiece 26. This results in vibrations caused by the long lever arms, which are absorbed as follows: The second end 22 of the drilling rod 20 is arranged or fixed in a support device 31, which is shown schematically in Fig. 3. For example, the support device 31 can comprise two half-ring elements 41a, 41b, which completely surround the drilling rod 20 and can be fastened to one another by means of clamping areas 42.

The support device 31 is arranged on a separate component 34, which has a positive guide device 33 for providing a guide track 32. According to Fig. 3, the component 34 has a base 35 and two side wall areas 36a, 36b.

Two guide rails 37a, 37b are arranged on the base 25, along which a support carriage 39 can be moved by means of recirculating ball guides 38. The support carriage 39 is connected to a carrier 40 to which the support device 31 is attached. The guide rails 37a, 37b are only indicated by dot-dash lines in Fig. 1.

Heinz Dietmar Sieper ·; ·.. : : .

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The component 34 is arranged according to Fig. 3 within the receiving trough 15 of the machine bed and can be inserted into the machine bed 12 from the right-hand end of the machine bed 12 as shown in Fig. 2, for example. Its side regions 36a, 36b engage under corresponding holding surfaces 45a, 45b of the machine bed 12 and can therefore no longer be removed from the machine bed 12 by a movement in the vertical direction ζ.

To fix the component 34 to the machine bed 12, fastening elements 43a, 43b, 43c, 43d in the form of clamping claws are provided, which can be fixed by means of fastening means 44a, 44b, 44c, 44d, which are designed as clamping screws.

The component 34 fixed in the machine bed 12 provides a positive guide device 33 for the support device 31. In this regard, it should first be noted that the support device 31 can also be displaced in the direction of the double arrow y and in the direction of the double arrow ζ and can be fixed in selectable positions in order to be able to adjust the support device 31. The arrangement consisting of the support slide 39 and the carrier 40 can therefore also be designed as a cross slide. Any adjustment devices provided are not shown in Fig. 3, which is to be understood as merely schematic.

It is crucial that the support device 31 can be displaced at least indirectly via a support carriage 39 in the axial direction &khgr; relative to the machine bed 12, wherein the support carriage 39 uses the recirculating ball guide provided by the guide rails 37a, 37b as a positive guide device 33. The positive guide device 33 thus provides a guideway 32 for the support device 31 that runs only in the axial direction &khgr;, so that after fixing the support device 31 relative to the support carriage 39 with regard to possible degrees of freedom in the transverse direction y and in the vertical direction &zgr;, the support device

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direction 31 only has one degree of freedom, namely the possibility of movement in the axial direction x.

In the event that the carriage 18 is displaced in the direction &khgr; during a machining operation of the workpiece 26, the boring bar 20 pulls the support device 31 behind it. Since the positive guide device 33 is provided independently of the machine bed 12, the positive guide device 33 can be manufactured and aligned with appropriate dimensions and optimized to the existing requirements. It should be emphasized in this context that the holding surfaces 45a and 45b intended for fastening the steady rest 29 can now be used to fasten the component 34.

From Fig. 1 and 2 it is clear that the component 34 extends along an axial length a, so that during the entire machining of the workpiece 26 a displacement of the support device

31 along the guideway provided by the component 34

32 is possible. The component 34 therefore extends to below the carriage 18 in its starting position in Fig. 1. Due to a design of the clamping elements 43a, 43b, 43c, 43d such that they only have a small height In ₁ or h ₂ , it is ensured that the component 34 fastened to the machine bed 12 can be easily traveled over by the carriage 18 and does not interfere with its movement.

Since the second end 22 of the boring bar 20 is optimally fixed by the support device 31 and can be moved along a very precise guideway 32, the first end 21 of the boring bar 20 does not have the degrees of freedom that are disruptive in the prior art, so that the machining of the workpiece 26 is improved. This means that work can be carried out either with greater precision or at a higher working speed.

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In the case of particularly long workpieces 26, as shown for example in Fig. 4, the component 34 can also be fastened to the machine bed 12 in a fastening position in which the component 34 protrudes freely beyond the machine bed 12 (cf. excess length m in Fig. 4). This enables a particularly simple extension of the machine bed 12, which does not require any additional structural effort.

It should be emphasized that the component 34 can be used in a variety of different devices 10 of the prior art and can be exchanged as required, since the machine beds 12 of the known devices 10 vary only slightly. The component 34 provides an inexpensive, universally applicable positive guidance device that is separate from the machine bed 12.

The existing prism surfaces and contact surfaces 16a, 16b, 16c, 16d, 17a, 17b, 17c, 17d, 17e, 17f, 17g, 17h, which are not suitable for precise guidance of the support device 31 and are regularly very heavily soiled, can be used as fastening surfaces for the component 34, but make their use as a guide surface unnecessary.

If the component 34 is to protrude beyond the free end of the machine bed 12, care must be taken to ensure that more than half of the axial length a of the component 34 overlaps with the machine bed 12 in order to ensure sufficient stability. If necessary, the component can be supported by means of angle elements, which can also be attached to the base 11 of the device.

Since the wearing parts are made of commercially available components, the device 10 according to the invention can also be easily repaired using simple means.

Claims (14)

1. Device ( 10 ) for the internal machining of tubular workpieces ( 26 ), comprising a rotationally driven chuck ( 25 ) for the workpiece and a carriage ( 18 ) which is movable on a machine bed ( 12 ) in the axial direction (x) for holding, in particular for holding essentially centrally, a boring bar ( 20) carrying a tool (23 ) which projects from the carriage with its first end ( 21 ) axially in the direction of the chuck ( 25 ) and with its second end ( 22 ) from the carriage ( 18 ) in the opposite direction, characterized in that a support device ( 31 ) is provided for the second end ( 22 ) of the boring bar ( 20 ), which can be displaced in the axial direction along a guide track ( 32 ), the guide track being guided by a separate support device which can be at least indirectly fastened to the machine bed ( 12 ). Forced guidance device ( 33 ) is provided. 2. Device according to claim 1, characterized in that the positive guide device ( 33 ) is arranged on a component ( 34 ) separate from the machine bed ( 12 ). 3. Device according to claim 2, characterized in that the component ( 34 ) has fastening means ( 44 a, 44 b, 44 c, 44 d, 43 a, 43 b, 43 c, 43 d) for detachable connection to the machine bed ( 12 ). 4. Device according to claim 2 or 3, characterized in that the component ( 34 ) can be fastened to the machine bed ( 12 ) in a plurality of different fastening positions spaced apart from one another in the axial direction. 5. Device according to claim 4, characterized in that in at least one fastening position the component ( 34 ) projects in the opposite direction beyond the machine bed ( Fig. 4, distance m). 6. Device according to claim 5, characterized in that the component in its projecting fastening position covers the machine bed ( 12 ) with more than half of its axial length (a). 7. Device according to one of claims 2 to 6, characterized in that the component ( 34 ) has at least one guide rail ( 37 a, 37 b), in particular a pair of guide rails. 8. Device according to one of the preceding claims, characterized in that the machine bed ( 12 ) has a substantially groove-shaped receiving trough ( 15 ) extending in the axial direction (x). 9. Device according to claim 8, insofar as this is related to one of claims 2 to 7, characterized in that the component ( 34 ) fastened to the machine bed ( 12 ) with the positive guide device ( 33 ) is arranged substantially within the contour of the receiving trough ( 15 ). 10. Device according to claim 8 or 9, characterized in that the component ( 34 ) fastened to the machine bed ( 12 ) engages behind material areas (holding surfaces 45 a, 45 b) of the receiving trough ( 15 ). 11. Device according to one of claims 8 to 10, characterized in that the component ( 34 ) can be inserted axially into the receiving trough ( 15 ) from one end of the machine bed ( 12 ). 12. Device according to claim 11, insofar as this is at least indirectly related to claim 3, characterized in that the fastening means for securing the inserted component can be placed and/or actuated and/or released from an upper side of the machine bed ( 12 ). 13. Device according to one of the preceding claims, characterized in that the positive guide device ( 33 ) fastened to the machine bed ( 12 ) and/or a component ( 34 ) fastened to the machine bed ( 12 ) can be traversed by the carriage ( 18 ). 14. Forced guide device ( 33 ) for a support device ( 31 ) of a device ( 10 ) having a machine bed ( 12 ) for the internal machining of tubular workpieces ( 26 ), in particular a device according to one of the preceding claims, characterized in that the forced guide device ( 33 ) is arranged on a component ( 34 ) separate from the machine bed ( 12 ), and that the component ( 34 ) has fastening means ( 43 a, 43 b, 43 c, 43 d, 44 a, 44 b, 44 c, 44 d) for detachable fastening to the machine bed ( 12 ).