Abrading – Precision device or process - or with condition responsive... – With indicating
Reexamination Certificate
2000-05-10
2001-03-20
Eley, Timothy V. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
With indicating
C451S303000, C451S310000
Reexamination Certificate
active
06203402
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a device for belt-grinding curved work piece surfaces, comprising an acceptance device for the work piece, the acceptance device comprising means for turning the work piece and an oscillation means for oscillating the work piece in its axial direction, and with processing jaws with two processing arms, wherein each processing arm has, in the region of its free end, at least one processing shoe partially surrounding the work piece surface to be processed, and further comprising an abrasive belt extracted from a supply roller and guided between the processing shoes and the work piece surface to be processed and towards an extraction means.
Belt-grinding devices of this kind are well-known. Such devices are mainly used for finishing the bearing locations of crank shafts, cam shafts, gear shafts and connecting rod bearings on crank shafts. The bearings are post-treated after grinding using an abrasive belt, wherein the shape of the bearing and the roundness of the bearing are corrected to desired values. During super finishing, the abrasive belt is pressed onto the work piece surface by a processing shoe into which the processing shell has been inserted. The work piece is thereby turned and simultaneously reciprocated in the axial direction. The pressure is exerted by two processing shoes engaging the work piece, each pressing a portion of the abrasive belt onto the work piece. The processing time can be determined empirically with the work pieces being processed for an equal length of empirically determined time. This results in different processing results. Alternatively, e.g. the diameter of the work piece is measured during processing and processing is interrupted once a predetermined value has been reached. In processing devices of this kind having such an in-process measuring means, the work piece is processed from one side only, i.e. via a processing shoe, with the measuring device being disposed on the other side to carry out the measurement. Belt-grinding machines of this kind have the advantage of measuring processing development during the processing operation to permit an optimum finishing result. However, the processing time is considerably longer than with devices not having such in-process measuring means, due to the reduced surface area engagement of the belt.
It is therefore the underlying purpose of the invention to further develop a device of the above mentioned kind such that equally good processing results can be achieved with considerably reduced processing time.
SUMMARY OF THE INVENTION
This object is achieved in accordance with the invention in that a device of the above mentioned kind comprises an in-process measuring means for measuring, during processing, the work piece surface to be treated, the measuring means being disposed at the free end of one of the processing arms.
In the inventive belt-grinding device, the work piece is processed by two processing shoes and simultaneously measured during processing. This is possible by providing, in addition to the two processing shoes, an in-process measuring means which surrounds one of the two processing shoes. The in-process measuring means thereby surrounds the processing shoe directly in that plane in which the work piece is processed or measured. There is normally no space available next to the processing shoes, i.e. next to the work piece surfaces to be treated, since either other structural parts are disposed at this location or a further work piece surface to be treated is directly adjacent thereto. The in-process measuring means does not therefore surround the side of the processing shoe.
In a further development of the invention, the in-process measuring means is a measuring means for determining the diameter, the surface roughness, the conical slanting and/or crowning of the surface. In general, the diameter of the work piece section to be processed is measured, since it depends on the processing time. The conical slanting, surface roughness, crowning etc. are set through selection of the abrasive belt and the processing shoes or processing shells and optionally the bearing thereof.
In one embodiment, the in-process measuring means comprises at least two measuring probes, in particular, facing one another and having a DMS measuring bridge. The diameter of the work piece section to be processed is detected by seating these measuring probes on the surface to be processed. Evaluation of the measurement signals is carried out via a DMS bridge which is advantageously integrated into the in-process measuring means.
In another embodiment, the in-process measuring means is an optical, pneumatic or hydraulic measuring means. Measurement can be carried out e.g. by optical elements, such as a laser beam or the like, or using a fluid such as air or honing oil or the like. Pneumatic or hydraulic measuring means comprise measuring nozzles which guide the fluid to the surface to be processed or to a specially generated surface, and the back-pressure or flow is measured.
In a further development of the invention, the in-process measuring means is disposed on the processing arm associated with the supply roller. The processing shoe is thereby guided, together with the measuring means, to the work piece surface to be treated, or lifted therefrom through the closing or opening of the processing jaws. As soon as the measuring means detects the desired degree of processing, the closing pressure of the processing jaws is removed, wherein the two processing arms seat with low pressure on the work piece surface to be processed and are carried along therewith, e.g. at a crank pin. Opening of the processing arms is also possible for bearing locations without orbit.
In accordance with the invention, the processing shoes are provided with hard inserts and/or soft inserts e.g. made from vulkollan, an elastomer or the like. Appropriate combination of the inserts achieves optimum improvement of the cylindrical shape, the surface quality, the roughness or the reduction of conical slanting.
In a further embodiment, the processing shoes are provided with continuous area contact or slotted processing shells. Slotted processing shells, as disclosed in DE 44 44 239 A1, have the advantage that their encompassing diameter can be slightly altered to permit optimum adjustment to the diameter of the work piece section to be processed.
In a further embodiment, the processing shoes have rapid-exchange shells. Rapid-exchange shells of this kind are disclosed e.g. in DE 297 19 168 U1.
To guide the abrasive belt in the region of entrance into the processing shoe and in the region of exit from the processing shoe around or past the holding means of the measuring means in an as simple a manner as possible, the processing arm comprising the in-process measuring means has deflection means for the abrasive belt in the region of the processing shoe. These deflection means guide the abrasive belt, as mentioned above, in the processing plane past or through the holding arms for the probe arms or probe pins of the measuring means.
In a further development, the abrasive belt is turned or folded in its longitudinal direction by the deflection means through approximately 90°. By turning the abrasive belt through approximately 90°, it is directed parallel to the processing plane of the work piece or to the closing plane of the processing jaws and can therefore be introduced relatively easily into the processing region. At this location, the abrasive belt is turned back into the original position to enable flat abutment on the work piece surface to be treated. It is also possible to fold the abrasive belt so that it also extends parallel to the closing plane of the jaws. The side of the abrasive belt coated with grinding particles can thereby be folded toward the inside or outside.
The deflection means can thereby be formed as an opening which is circular, oval, rectangular, spiral, U-shaped and/or which is open at the edges. Moreover, the opening can rotate along its length. The abrasive belt is turned or f
Eley Timothy V.
Nguyen Dung Van
Supfina Grieshaber GmbH & Co. KG
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