Patent Application
20160082522
The invention relates to a material-removing machine tool according to the preamble of claim 1. According to a second aspect, the invention refers to a tool set. According to a third aspect, the invention relates to a method for production of a cylinder with a blind and/or stepped bore, particularly a deep-hole drilling method.
The production of cylinders usually requires at least three work steps, i.e. to drill out, skiving, and subsequent burnishing. This way, the high requirements to accurate form and surface needs of the cylinder's inner wall can be achieved.
The production of cylinders is particularly elaborate if they have a blind bore and/or a stepped bore. The reason for this is that the resulting chips must be transported away specifically when drilling out. This is only possible through the tool in a blind bore. To subsequently skive and burnish the cylinder's inner wall, at least another tool is needed, which requires a high fluid pressure, i.e. either for folding in and out of the skiving knives and/or to charge the rollers with pressure. This tool change is difficult because of the different requirements of the individual tools.
Specifically in production of larger lots, it has therefore become established to first drill out all workpieces, then to install the skiving tool and to perform the skiving treatment for all workpieces of the lot. The detrimental part of this procedure is that the re-clamping makes it difficult to achieve highest accuracies and that re-clamping is also high effort.
From DE 10 2010 013 480 A1, a material-removing machine tool is known in which the drilling head is connected to a drilling tube with a tool carrier. A direction control permits active influence on the processing direction during processing, increasing the achievable accuracy specifically in production of eccentric inner tube structures.
From DE 10 2011 110 044 B4, a method for producing a cylinder unit is known, with which the cylinder and the front can be processed in one clamp. To make do without additional components to switch the skiving knives used for skiving, the skiving knives can be switched with the cooling lubricant used for material removal.
From EP 048 578 A2, a tool holder is known that has a conical bore with which a truncated cone-shaped shaft of a tool can be fastened. The shaft is attached to the tool holder with a union nut tool holder. This kind of tool holder is not suitable for drilling open cylinders, since the transporting away of chips is not ensured.
From WO 2014/011 198 A1, a deep-drilling machine is known that has an adapter. The adapter permits a deep-drilling machine to drill open, skive and burnish non-continuous cylinders in one clamp. The skiving knives can be charged with pressure fluid by a central pressure line and thus switched. This deep-drilling machine has the disadvantaged of not being able to produce blind holes.
The invention is based on the task of improving the production of cylinders with blind and/or stepped bores.
The invention solves the problem with a machine tool with the characteristics of claim 1. According to a second aspect, the invention solves the problem by a tool set according to the secondary claim. According to a third aspect, the invention solves the problem by a method with the characteristics of the method claim.
The advantage of the invention is that even present material-removing machine tools, such as lathes or deep-drilling machines, can be upgraded for automatic tool change.
Another advantage is that the risk of damaging one of the threads involved during tool change and thus rendering the entire tool useless is much reduced. The tapered bore and the anti-rotation device make it possible to not completely bring the drill head into contact with the adapter axially flush, without endangering a thread by this. The drill head can be then aligned flush with the adapter by pushing it into the adapter. When this has been achieved, the drill head is firmly connected to the adapter with the union nut.
The adapter according to the invention permits, depending on tool type, machine type and processing task, to discharge essentially pressure-free cooling lubricant with chips, providing hydraulic pressure to control a skiving tool or cooling lubricant with a pressure of more than 40 bar for cooling the blades and material removal as well as concurrent tool control.
In the scope of this description, the material-removing machine tool may be a deep-drilling machine. A deep-drilling machine specifically is a device constructed to drill holes with an aspect ratio of at least 10 in workpieces of metal. The aspect ratio is the quotient of length of the bore and its diameter. Such deep-drilling machines are special machines, since deep drilling must be performed with a sufficient accuracy so that specifically hydraulic cylinders can be produced.
The drill head is a unit that can be separated from the adapter and the tool holder, on which a blade or several blades are formed with which the cylinder inner face of the resulting cylinder is processed. The anti-rotation device is specifically a device that prevents a twist between the adapter and drill head in at least one direction. However, it is particularly beneficial if the anti-rotation device prevents twisting of the drill head and adapter relative to each other in both rotating directions. For example, the anti-rotation device comprises a fitted key or a fitted pin.
The term of torque-proof means that a torque can be transmitted in at least one rotating direction from the one object, in this case the tool holder, to the other object, in this case the base. It is possible, but not necessary, that a torque can be transmitted in both directions.
According to a preferred embodiment, the adapter has a base to which the union nut is attached, and a ring element that is placed between a front face of a tapered shaft and the base so that the central channel for the machining direction of the drill head is free of undercuts. This ring element is preferably made of a material that is more elastic than the material of which the base and/or the tapered shaft of the drill head are made.
This way, the ring element will deform more easily than the adapter or the drill head, and their fitting accuracy relative to each other is not influenced by the ring element.
The characteristic that the central channel is undercut-free at least regarding the machining direction of the drill head between the front face and an opposite face of the adapter, specifically means that an imagined ball with a diameter of 1 mm, when moving in the machining direction of the drill head from the input side to the output side along the inner wall of the adapter and drill head, will at no point be moved radially outwards by more than 1 mm. In reverse, this means that chips that flow from the drill head onto the input side will not be subjected to any radially inward pointing edge where they could catch. This ensures optimised chip flow.
According to one preferred embodiment, the material-removing machine tool in the form of a CNC-lathe has a pressurised fluid line that runs through the central channel, and a drill head cooling lubricant line that is connected to the adapter cooling lubricant line and that has an opening at a radially outer face of the drill head, so that cooling lubricant from the adapter-cooling lubricant line can be supplied to a space between the drill head and an inner wall of the workpiece. Both cooling lubricant lines are specifically formed for conducting cooling lubricant with a pressure of at least 50 bar.
It is particularly beneficial when the material-removing tool also comprises a skiving tool that can be connected positive-lockingly to the adapter as an alternative for the drill head, with the skiving tool comprising a tapered shaft for form-locking connection of the tapered bore of the adapter and a skiving tool-cooling lubricant line that is formed so that it can be connected to the adapter-cooling lubricant line and an opening at a radially outer face of the skiving too, so that cooling lubricant from the adapter-cooling lubricant line can be supplied to the space between the skiving tool and the inner wall of the workpiece.
It is of particular advantage when the drill head, the skiving tool and the burnishing tool are provided in a tool magazine that can be actuated automatically, which can be controlled from a machine control of the material-removing machine tool. Particularly preferentially, the material-removing machine tool comprises an automatically controllable gripper unit comprising a gripper that is formed for positive-locking connection to the union nut, so that the connection between adapter and drilling head can be released and/or produced automatically. The positive-locking connection can be achieved, e.g. by interlocking of the gripper in a recess of the drill head and/or interlocking of the protrusion of the union nut with a recess of the gripper. Of course, a friction-locking connection is generally imaginable as well, even though these can usually transmit only lower torques.
It is of particular advantage if the material-removing machine tool also comprises a rolling tool that can be connected positive-lockingly to the adapter as an alternative for the drill head, and a tapered shaft for a positive-locking connection to the tapered bore of the adapter and a rolling tool-cooling lubricant line that is formed connectable to the adapter-cooling lubricant line and that comprises an opening at a radially outer face of the burnishing tools, so that cooling lubricant from the adapter-cooling lubricant line can be supplied to a space between the burnishing tool and an inner wall of the workpiece. This burnishing tool can be used for final processing of a cylinder.
Due to the presence of the tapered shaft and tapered bore with anti-rotation device, it is possible to provide for an automatic gripper, since the accuracies achievable with grippers usually are not sufficient to screw a thread directly. The construction of the adapter, however, leads to an increased alignment tolerance of the system, so that the accuracy that can easily be achieved with an automatic gripper is sufficient to connect the tools to the adapter and loosen them from it.
It is of particular advantage if the gripper if formed turning relative to a holder of the gripper. A particularly simple setup results when the rotation between gripper and holder can be achieved by a cylinder, specifically a hydraulic cylinder. This cylinder can then be charged with pressure fluid, specifically cooling lubricant, and a hydraulic fluid that can also be used to actuate the skiving knives of the skiving tool.
Preferably, the adapter, in particular the union nut, and the respective tool are formed so that the die union nut can be moved from the locking position in which the drill head is positive-lockingly connected to the adapter, into a release position, in which the drill head can be moved in the axial direction relative to the adapter by turning it by no more than 90°, specifically no more than 80°. This movement can be performed by the gripper relative to its holder by actuating a drive cylinder, that the gripper can be easily controlled.
Preferably, the adapter has an output valve on the output side that comprises an output valve body that can opens the output valve by movement toward the input side. It is beneficial when the drill head, the skiving tool and/or the fixed roller tool comprise a handover valve that comprises a handover valve body that closes the handover valve by movement in the axial direction away from the adapter. This prevents the fluid, specifically cooling lubricant and/or pressure fluid from escaping at disconnection.
According to a preferred embodiment, the adapter has a central pressurised fluid line, placed in the central channel and connected to a pressure fluid supply unit for charging with fluid pressure on the side towards the workpiece holder, so that the fluid pressure can be transferred from the input side to the output side.
The pressure fluid supply unit specifically comprises a cooling lubricant supply unit and/or a hydraulic fluid supply unit. The central pressurised fluid line permits, e.g., conducting hydraulic fluid to a skiving tool that is connected to the adapter. The fluid pressure of the hydraulic fluid permits retraction and/or extension of a skiving knife. In this case, the machine tool preferably has a cooling lubricant supply unit with which the cooling lubricant can be supplied to a space between the skiving tool and an inner wall of the workpiece.
Preferably, the tool holder is formed hollow, so that a channel is formed. It is beneficial when the channel is connected to the pressure fluid supply unit so that pressure fluid can be routed through the tool holder in the form of cooling lubricant and/or pressure fluid in the form of hydraulic fluid. Alternatively or additionally, the tool holder is connected to the pressure fluid supply unit so that cooling lubricant from the central channel of the adapter can be routed through the tool holder to the cooling lubricant supply unit that cleans the cooling lubricant with a filter and routes it under pressure to the adapter and/or through a cooling lubricant line into the space between the skiving tool and an inner wall of the workpiece.
According to the invention a material-removing machine tool, specifically a deep-drilling machine or CNC-lathe, with (a) an adapter that (i) can be connected to a tool holder of a material-removing machine tool torque-proofly, and (ii) a union nut comprising an adapter-thread and (iii) a tapered bore, with the adapter comprising a input side facing towards the tool holder and an output side facing away from the tool holder, and a central, continuous channel, through which chips can be removed opposite a processing direction of the drilling-open tool, and with (b) a drill head, comprising (i) a drill head thread for form-locking interaction with the adapter thread and (ii) a tapered shaft for form-locking interaction with the tapered bore, with (c) the adapter comprising an adapter guiding surface and the drill head comprising a drill head guiding surface, which interact to prevent twisting of the drill head and adapter relative to each other, with (d) the tool set comprising a skiving tool, specifically a combined skiving-burnishing tool comprising a skiving tool guiding surface that is formed for interaction with the adapter guiding surface to prevent twisting of the skiving tool and adapter relative to each other.
The following explains the invention in more detail based on the enclosed drawings. Therefore
The machine tool 10 has a pressure fluid supply unit that comprises a cooling lubricant supply unit 24, through which cooling lubricant can be supplied via a cooling lubricant supply line 26 into a space 64 (see below,
The workpiece 30 is clamped in the workpiece holder 14. The workpiece holder 14 and tool holder 16 can be moved towards each other linearly guided by a motor. The corresponding guide and the drive motors or the drive motor are not drawn in, as they are part of prior art.
The adapter 20 comprises a tapered bore 38, with this tapered bore specifically being a recess rotationally symmetric around a rotating axis L, the radius of which increases monotonously, specifically strictly monotonously, with increasing distance from a input side 40 of the adapter 22. Therefore, it is possible and preferred, but not necessary, that the inner contour of the tapered bore 38 is a truncated cone in the mathematic sense.
The adapter 20 also comprises an anti-rotation device 42, in this case comprising two tappets that are inserted into longitudinal grooves. In the adapter 20, a central, continuous channel 44 is formed that is connected to a drill head-channel 46 of the drill head 22. The adapter-thread 36 combs with a drill head-thread 48 of the drill head 22, so that a tapered shaft 50 of the drill head 22 can be pulled form-lockingly connected to the tapered bore 38. In this condition, a shoulder 52 of the drill head 22 and an opposite application surface 54 of the base 32 are flush against each other and ensure a stiff connection.
Between a front face 56 of the tapered shaft 50 and a supporting surface 58 of the base 32, a ring element 60 segmented depending on the number of tappets 42 is placed. This ring element 60 fills the otherwise present undercut im the area between tapered shaft 50 and base 32, so that a continuous transfer results between the drill head-channel 46 and the central channel 44. This prevents chip accumulation.
a shows schematically how cooling lubricant 62 is supplied to a space 64 between workpiece 30 and drill head 22. This cooling lubricant 62 is removed in blind hole processing together with the resulting chips through the drill head-channel 46, which is open towards the front face of the drill head 22, and thus enters channel 44 (
From there, the cooling lubricant enters a bore 66 in the tool holder and is supplied to a cooling lubricant treatment system from there.
In the right partial figure, recesses 67.1, 67.2, 67.3, 67.4 are shown, which are introduced into the union nut 34, so that a gripper described above can positive-lockingly, i.e. form-lockingly, interlock with them.
The skiving tool 70 comprises an input opening 72 that is formed to connect to the pressurised fluid line 68 and that is formed at a pressure channel 64. The pressure channel 64 leads to a control cylinder not drawn in
b shows an alternative skiving tool 70, which comprises a skiving tool-cooling lubricant line 68 that also is connected to a channel 88, in turn connected to the pressurised fluid line 68 (cf.
c shows an alternative rolling tool 82 with a rolling tool-cooling lubricant line 90, which is also connected to a channel 92, which in turn is connected to the pressurised fluid line 68 in operation.
The gripper unit 94 can be positioned automatically. For example, it is attached to a tool changer of the machine tool, so that the gripper 96 can be positioned automatically by a machine control of the machine tool that is not illustrated. For this purpose, it is beneficial if the machine tool is formed to bring the workpiece holder to a specifiable angle position. In other words, it is beneficial if the machine tool comprises an angle encoder based on which the angle position of the tool holder can be specified relative to the machine frame. However, it is also possible that the gripper unit is attached relative to the machine bed and comprises a dedicated control unit by which the gripper 96 can be positioned. In this case, it is beneficial if the machine control with the control of the gripper unit is at the bottom so that a programme running on the machine control can also position the gripper.
Since the respective tool 22, 70, 82 as shown in
A method according to the invention is performed by initially clamping a workpiece in the form of a cylinder blank on the machine tool 10. Then the workpiece inside 80 is drilled out with the drill head 22. Subsequently, the drilling head is released from the adapter by positioning the gripper unit automatically as described above and loosening the connection between the union nut and the drilling head 22 by turning the gripper 96.
Then the drill head is automatically put down by the gripper unit, e.g. in a tool magazine, and the skiving tool is collected and automatically connected to the adapter, with the connection connecting the pressurised fluid line 68 (cf.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 209 243.1 | May 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/001302 | 5/14/2014 | WO | 00 |
