Background of the invention

[0001] The invention relates to an operating module for performing power skiving machining tasks, in particular a module configured to be removably mounted on a tool- holding turret of a numerically controlled machine tool.

[0002] Specifically, but not exclusively, reference is made to a tool-holding module for power skiving that is mountable on a tool-holding turret of a numerically controlled lathe and is drivable by the lathe itself.

[0003] For the industrial manufacture of gears, the machining technology called power skiving is known. Patent publication DE 243514 discloses the first example of a power skiving process for machining toothed wheels.

[0004] In general, the workpiece, after it has been partially machined on a numerically controlled lathe, is removed and then positioned on a machine for power skiving that makes the toothing desired to obtain the finished workpiece. In the power skiving process, the rotation axis of the tool is placed at a desired cross angle with respect to the rotation axis of the workpiece. During machining, moreover, a relative axial movement between the tool and the workpiece is controlled.

[0005] The prior-art power skiving technology is expensive because both a numerically controlled lathe and a gear cutting machine for power skiving must be available. This also requires sufficiently large space to receive the machines.

[0006] The known process is moreover long and laborious because it requires the partially machined workpiece to be removed from the lathe and be positioned on the power skiving machine that makes the toothing. Possible positioning errors on the power skiving machine can also result in imprecise machining.

[0007] Further, it is complicated to perform machining tasks in phase, such as, for example, arranging a hole in a precise position in relation to the toothing.

Summary of the invention

[0008] One object of the invention is to provide means for performing power skiving that is able to overcome one or more of the aforesaid drawbacks of the prior art.

[0009] One advantage is to make means for performing power skiving by using a machine tool that also performs other tasks (drilling, milling, etc).

[0010] One advantage is to shorten the time to prepare the machine for performing toothing and the time to machine the workpiece. [0011] One advantage is to increase productivity and versatility in manufacturing short and medium runs of workpieces provided with external and/or internal toothing.

[0012] One advantage is to improve the machining precision of external or internal gears that were previously machined by a numerically controlled lathe.

[0013] One advantage is to provide an operating module that can be driven by a drive with which a tool-holding turret is provided.

[0014] One advantage is to make available an operating module that can be mounted on any driven tool-holding turret.

[0015] One advantage is to make an operating module that enables the performance and versatility of the numerically controlled machine to be improved that has the tool- holding turret on which the module is mounted.

[0016] Such objects and advantages, and still others, are achieved by the module for power skiving according to one or more of the following claims.

[0017] According to the invention, a tool-holding module is made that is mountable on a tool-holding turret of a numerically controlled machine; the module holds a tool for power skiving with the possibility of adjusting the angular position thereof around an adjusting axis; the module has a tool-driving rotor that is connectable to a drive of the tool-holding turret so as to receive mechanical energy through the drive.

[0018] The tool-holding module enables toothing to be made on a workpiece by means of the aforesaid numerically controlled machine.

[0019] The tool-holding module is constructionally cheap and simple and can effectively replace a dedicated machine for power skiving.

[0020] The tool-holding module enables the precision of gear cutting to be improved because all the other required workpiece machining tasks, in addition to generating the toothing, can be performed on the same machine tool. In other words, it is not necessary to reposition the workpiece on another machine.

[0021] In one embodiment, a module for power skiving is configured for mounting on a tool-holding turret of a numerically controlled machine, the module comprising a toothed tool for power skiving that is rotatable by a rotor provided with mechanical connecting means to a drive of the tool-holding turret, the rotor being rotatably coupled with supporting means having the possibility of adjusting the angular position thereof with respect to the turret by rotating around an adjusting axis.

Brief description of the drawings [0022] The invention can be better understood and implemented with reference to the attached drawings that illustrate one embodiment thereof by way of non-limiting example.

[0023] Figure 1 is a perspective view of an embodiment of a module for power skiving made according to the present invention.

[0024] Figure 2 is a partially sectioned side view of the module of figure 1.

[0025] Figure 3 is a view from the right of figure 2.

[0026] Figure 4 is a side view of the module of figure 1 during the machining of an internal toothed wheel.

[0027] Figure 5 is a view from the right of figure 4.

[0028] Figure 6 is a top view of figure 4 which is partially sectioned in the machining zone according to the plan of section VI- VI.

Detailed description

[0029] With reference to the aforesaid figures, with 1 overall a module for power skiving has been indicated that is intended for mounting on a tool-holding turret of a machine tool and is drivable by the machine tool. The module 1 for power skiving is in particular intended for mounting on a turret of a numerically controlled lathe.

[0030] The tool-holding turret (which is for example of known type and is not illustrated) may be set up for receiving a plurality of interchangeable operating modules.

[0031] The module 1 for power skiving may be, for example, mountable on a tool- holding turret of the twelve-position type.

[0032] The module 1 may comprise, as in this example, first supporting means 2 intended for fixing on the tool-holding turret. The first supporting means 2 may be fixed to the turret by removable locking means, for example screw-type locking means.

[0033] The module 1 may comprise, in particular, second supporting means 3 that is rotatably coupled with the first supporting means 2 with the possibility of adjusting the angular position thereof with respect to the first supporting means 2 by rotating around an adjusting axis H. The second supporting means 3 may comprise, in particular, a plurality of elements that are mutually interconnected to support various components of the module 1, as will be explained better below.

[0034] The module 1 may comprise, for example, a rotor 4 that is rotatably coupled with the second supporting means 3 around a first rotation axis J that may coincide, as in this example, with the adjusting axis H.

[0035] The rotor 4 may be provided with mechanical connecting means 5 to a drive of the tool-holding turret in such a manner that the rotor 4 receives mechanical energy through the drive. The mechanical connecting means 5 may comprise, for example, a shaped male element.

[0036] The module 1 may comprise, in particular, a toothed tool 6 for power skiving intended for machining a workpiece P rotatingly supported by the machine tool. The toothed tool 6 may comprise, for example, any tool of known type that is usable for power skiving tasks.

[0037] The toothed tool 6 may be rotated by the rotor 4 around a second rotation axis W supported by the second supporting means 3. The second rotation axis W may be connected to the first rotation axis J by means of a mechanical transmission system supported by the second supporting means 3.

[0038] The angular position of the second supporting means 3 may be adjustable around the adjusting axis H, in particular, within an angular range that is not less than 20° (adjustment range + 10° around a preset reference zero), or not less than 30°, or not less than 40°, or not less than 50°. In particular, the angular position of the second supporting means 3 may be adjustable around the adjusting axis H for a complete revolution angle of 360°. The orientation of the second supporting means 3, and thus the orientation of the axis of the tool 6 carried by the second supporting means 3 around the axis H, may be adjusted manually by a user. The second supporting means 3 is lockable in position with respect to the first supporting means 2 by means of removable locking means (for example of the screw type). In order to adjust the orientation around the axis H, the user will release the second supporting means 3, will rotate the second supporting means 3 until it reaches the desired orientation (assisted therein by suitable graduated scale means), lastly, the user will lock the second supporting means 3 on the first supporting means 2 in the desired position reached.

[0039] As said, the module 1 may comprise, for example, graduated scale means 7, which may be arranged on the first supporting means 2 and/or on the second supporting means 3 to facilitate orientation in position by a desired angle around the adjusting axis H of the second supporting means 3 with respect to the first supporting means 2. The graduated scale means 7 may be arranged to perform a complete revolution angle of 360°. In the specific case, for ease of representation, the numbering in degrees on a graduated scale means 7 has been illustrated only partially.

[0040] The graduated scale means 7, which is in particular arranged for indicating a relative angular position of the second supporting means 3 with respect to the first supporting means 2, may comprise, in another optional body that is not illustrated, a digital indicator that could comprise sensor means (for example electronic reading means, of optical, or magnetic, or capacitive, or resistive type, etc) arranged for reading a value of the aforesaid relative angular position by the graduated scale means and display means arranged for displaying the value read by the sensor means.

[0041] The second supporting means 3 may comprise, as in the case in point, a tubular portion 8 into which the rotor 4 is at least partially insertable. The rotor 4 may be, in particular, rotatably coupled with the tubular portion 8.

[0042] The first supporting means 2 may comprise, for example, at least a first flange portion 9 (fixed to the body of the tool-holding turret) into which the aforesaid tubular portion 8 is at least partially insertable. The second supporting means 3 may comprise, in particular, a second flange portion 10 that may be made integrally as a single piece with the tubular portion 8. The second flange portion 10 may be rotatably coupled in contact with the first flange portion 9.

[0043] The graduated scale means 7 may be arranged at least partially on the first flange portion 9 and/or on the second flange portion 10.

[0044] The module 1 may comprise, as in this example, at least one toothed wheel 11 that is rotatably carried by the second supporting means 3 around a third intermediate rotation axis K arranged for transmitting mechanical energy from the first rotation axis J to the second rotation axis. The toothed wheel 11 may be, for example, a conical wheel. The toothed wheel 11 may be coupled with a toothed wheel 18 carried by the second rotation axis W.

[0045] The third rotation axis K may comprise a further (for example cylindrical) toothed wheel 19 that is coaxial with the toothed wheel 11. The further toothed wheel 19 of the third rotation axis K may be coupled with a (for example cylindrical) toothed wheel 20 carried by the first rotation axis J.

[0046] The third rotation axis K may be, for example, transverse, in particular perpendicular to the second rotation axis W.

[0047] The third rotation axis K may be, in particular, parallel to the first rotation axis J and/or parallel to the adjusting axis H.

[0048] In one embodiment that is not illustrated, in which the third rotation axis K is absent, it is possible to arrange a conical toothed pair mounted on the first rotation axis J. [0049] The second rotation axis W may be, for example, transverse, in particular perpendicular, to the first rotation axis J.

[0050] The first rotation axis J and the second rotation axis W may be, as in this example, incident to one another.

[0051] The second rotation axis W may comprise, in particular, a spindle shaft 12 that may carry a quick connection at one end. This quick connection may comprise, as in this example, a tool carrier 13 that carries the aforesaid toothed tool 6 for power skiving. The quick connection may comprise, in particular, a ring nut 14 engaged with the tool carrier 13 and with the spindle shaft 12 to removably fix the tool carrier 13 to the spindle shaft 12. Optionally, the ring nut 14 could be rotatably mounted on the spindle shaft 12 and could have a side wall that is conformed so as to engage with a screwing tool.

[0052] The tool carrier 13 may comprise, in particular, a shank 15 coupled in a shapingly coupled manner with a seat obtained in the spindle shaft 12.

[0053] The second supporting means 3 may comprise, as in this example, a box body 16 (for example integrally fixed to the second flange portion 10) which contains and rotatingly supports the spindle shaft 12. The box body 16 may at least partially contain and/or at least partially rotatingly support the toothed wheel 11.

[0054] The module 1 may comprise, as in this example, dispensing means 17 arranged for dispensing a lubricating and/or coolant fluid by directing the fluid to a work zone of the tool 6. Such fluid dispensing means 17 may comprise one or more conduits that emerge, for example, from the second flange portion 10. The fluid dispensing means 17 may be supported, in particular, by the second supporting means 3.

[0055] The module 1 for power skiving may enable, as in this case, both internal and external gears to be generated.

[0056] In use, the module 1 is installed on the tool-holding turret of the numerically controlled lathe, in such a manner that the rotor 4 can take the mechanical energy supplied through a drive on the turret. The tool 6 can be oriented at the desired angle with respect to the rotation axis of the workpiece P rotatingly supported by the lathe, depending on the cross angle desired during the process of generating the toothing by power skiving. When the tool 6 is oriented, the process of power skiving can commence.

[0057] The motor of the turret rotates the rotor 4, which in turn rotates the tool 6, whilst the workpiece P is rotated by the lathe. The workpiece P may be provided with axial movement in relation to the tool 6 so as to perform toothing. This axial movement may be supplied to the workpiece P by the lathe itself and/or to the tool 6 by a carriage that carries the tool-holding turret. The workpiece P may be further provided with the possibility of another movement with respect to the tool 6, which is orthogonal to the aforesaid axial movement, for example an orthogonal movement supplied to the workpiece by the lathe and/or to the tool by the turret-carrying carriage. The lathe thus permits adaptation to power skiving for workpieces of various dimensions.