The invention concerns a device and a method for machining a cylindrical bore, preferably a cylinder bore of an internal combustion engine.
The device for machining a cylindrical bore, preferably a cylinder bore of an internal combustion engine, comprises a base member, a first machining tool with at least one geometrically defined cutter and a second machining tool with at least one geometrically undefined cutter, as disclosed, for example, in DE 103 59 347 B3. In this device, a fine boring tool and a honing tool are integrated into the base member wherein the fine boring tool is arranged at an end face of the base member and produces the bore with the desired dimension in a first machining step. Subsequently, when the device is moved farther into the cylinder bore, the honing stones of the honing tool are being employed and the surface is honed to have the desired functional roughness. Because of the fixed correlation and arrangement of the two tools, it is ensured that with one clamping action the fine boring action as well as the honing action are realized and thus the excess material required for the honing step can be minimized. Moreover, the nonproductive time periods for changing the tool or for reclamping the tool are eliminated. As a whole, a shortened machining time is achieved in this way.
However, this combination tool can only be used when it can be moved to a sufficient depth into the workpiece because the fine boring tool is arranged in front of the honing tool in axial direction. Also, the rigidity of the precision turning tool is reduced due to the long configuration which has a negative effect on the machining precision and the performance.
Moreover, it is also known to provide bevel cutters at a honing tool above the honing stones. The bevel cutters that have a geometrically defined cutting edge serve for providing a bevel at the cylinder bore after completion of the honing process.
EP 0046806 B1 discloses a combined fine boring and honing tool in which the cutters and the honing stones are designed to be feedable. A disadvantage of the type of feed action disclosed in this document is the obtainable precision of the feed action. Also, the contact forces existing between the honing stones and the workpiece cannot be acquired.
A basic machine for use with the device according to the invention is disclosed in DE 10 2007 045 619 as a flexible machining apparatus with various machining units for honing and/or fine boring. Reference is being had to the disclosure of this application.
The invention has the object to provide a device that enables various machining operations and machining cuts on cylindrical bores with one clamping action so that the productivity is increased, the quality is improved, and, by means of the machine tool, very different customer demands can be realized in a flexible manner and without complex conversions.
This object is solved according to the invention in connection with a device for machining a cylindrical bore, wherein the device has a base member, a machining tool with at least one geometrically defined cutter, and a machining tool with at least one geometrically undefined cutter, in that both machining tools are moved by separate pressure rods.
Feeding of the two machining tools independent of each other by means of pressure rods in accordance with the invention makes it possible to realize the feed action with very great precision and to increase as a result of this the precision with which the cylinder diameter can be produced.