DE2810322C2 - Honing machine - Google Patents

Description

50

The invention relates to a honing machine for eggs Preamble of claim 1.

When fine machining workpieces by honing, it is not only possible to achieve an excellent surface finish can be achieved, but also great accuracy of the circular shape and the cylindricity. Often However, the workpieces are honed in a condition that does not correspond to the final condition. For example, when machining the piston flanges on cylinder blocks, the cylinder block is made brought into the honing machine and machined to the most precise circular and cylindrical shapes. If the cylinder heads are then screwed on in the course of assembly, this can result in an essential The cylinder blocks are braced, causing deformation to occur on the piston liners, which produces a circular or cylindrical shape error of 0.05 to 0.15 mm. The effects of this failure are produced during engine production due to the high pressure exerted by the piston rings on the piston raceway This compensates for a very high level of friction, which not only extends the service life of the Engines affected, but also consumed a few percent of engine power.

From US patents 20 06 158 and 20 06 159 is a device for finishing cylinder blocks by grinding, which is applied to a cylinder block can be put on and braced with it, known This is what later becomes the bracing of the cylinder block simulated by the cylinder head. For this purpose, a clamping plate must be screwed onto the cylinder block in order to then attach the device to it. This device is unsuitable for ongoing production

The object of the invention is to create a honing machine in which, compared to a conventional honing machine, it is possible to machine workpieces with stress simulation even in ongoing series production with little additional effort
This object is achieved by the features of the characterizing part of claim 1

The workpiece fed to the honing machine is thus on the clamping part of the honing machine by the actuatable clamping devices, for example mechanical screwdrivers, so clamped that this is the later The state present during assembly corresponds to In this state the honing takes place, and then the tension is released again. The tension can be repeated on the same workpiece be made, especially before the honing process, so that the influence of permanent Deformations, for example due to machining burrs, inaccuracies in the fastening threads or the like. are balanced before honing and no longer have an effect during subsequent assembly come. In the same way, you can also use the same machine for successive honing processes the clamping devices must be actuated for releasing and tensioning before each honing process.

A particularly advantageous feature of the invention is that in a honing machine with a measuring device this a measuring tool for the dimensions or the shape of the hole in the clamped state of the Has workpiece. A measurement of the workpiece surface to be machined is therefore carried out in the state the only thing that matters, namely the condition as it is after final assembly. Except the measurement in the honing machine itself, for example by measuring nozzles t.n the honing tool, can also Pre- or post-measuring stations can be provided. So z. B. the honing machine with a bore measuring station be assigned to a clamping part and clamping devices, which can be actuated for clamping before the measurement. The bore measuring station can, however, also be a re-measuring station with a control feedback to the honing machine be. As a result, deviations from the desired dimensions in the clamped state are immediate considered. If the bore measuring station has a pre-measuring station with a clamped shape, too The workpiece being machined is measuring the workpiece, so can also move from workpiece to workpiece different form errors can be corrected immediately.

It is advantageous that by reworking the clamping part or setting the clamping devices accordingly the final state can be simulated particularly precisely.

Replace the clamping part and the clamping devices

preferably the normal clamping of the workpiece on the honing machine. In addition, a another clamping part can be attached to the same workpiece, for example if a workpiece is in the Practice is exposed to the tensing effect of two Tejie. This would be for example one particularly light cylinder block possible, on the one hand with a cylinder head and on the other hand with is clamped in a separate crankcase. Preferably, the clamping devices graze with the corresponding fastening points of the workpiece are assembled, for example in the case of a cylinder block with the threaded holes for the cylinder head screws. However, it would also be possible through others from machine-driven clamping devices clamping devices to the real state of tension simulate.

It can therefore be seen that the workpiece surfaces to be machined are produced in this way by the invention can that their high accuracy is available when it is actually required, namely in the assembled State. The invention also ensures that defects in the workpiece do not have any negative effects. This can include, for example, casting defects in the workpiece, such as wall thickness fluctuations, voids, etc. be. Since a deformation that has changed compared to the normal workpiece is already present when it is braced At the beginning of the honing process, this can either if it is still in the area of the machining allowances is to be compensated immediately, or it will be due to measuring devices or also due to the impossibility of reaching the tolerances was recognized during machining, so that the faulty Workpiece can be eliminated. In practice, a better workpiece will be a smaller one Error quota produced This advantage works up to an improved performance with considerable energy savings when the invention is applied to cylinder blocks of engines.

Further advantages and features of the invention emerge from the discrepancies and the description in Connection with the drawings. Embodiments of the invention are shown in the drawing and are explained in more detail below. It shows

F i g. 1 a honing machine according to the invention and a measuring station in a schematic front view,

F i g. 2 shows a view of the honing machine in the direction of arrow II as in FIG. 1 seen

3 shows an enlarged detail section according to the Line III-III in FIG. 1 (top view of the clamping part) and

4 shows an enlarged detail section according to the Line IV-IVb Fig. 3.

In the F i g. 1 and 2, a honing machine 11 is shown which has a machine frame 12. A honing spindle 14, which is normally arranged vertically and can be driven in a vertical direction and rotatably, carries a honing tool 15, which is preferably also provided with measuring nozzles 27. There are three measuring nozzles arranged one behind the other in the axial direction and connected to an evaluation device, not shown, with which the shape of a workpiece bore can be measured. So it is not only the tolerance at a certain point that is determined, but also deviations from the roundness and from the cylindrical shape. However, the measuring device could also make do with only one measuring nozzle, which not only rotatably but displaceably rt \ during the measurement, if necessary, also in Bohrungsiängsiichtung

On the frame 12 of the rknsmsüiine 11 is a

Workpiece table 13 is provided, dar h>&.; Tnncpori.fjr-hnine 28 of the workpiece, ie in FIG. 1 from the left -nsch rechis (and back), is displaceable. This has the shape of a strong and torsionally rigid plate with a rectangular basic shape (Fig. 3), at its four corners

ίο attack the supports 19. So it forms the upper one Carrier of a bridge or a tunnel.

The clamping part 18 has openings 22 which are aligned with the workpiece bores 17 to be machined in a workpiece 16. In any case, the openings are so large that the honing tool 15 can be run through them into any workpiece bore. In the present case, the workpiece is shown as a cylinder block with three piston tracks
Clamping devices 20 are arranged on the clamping part 18 in the form of screwdrivers, which can be driven mechanically, electrically, pneumatically or hydraulically, whereby, for example, a common drive can also be provided for several clamping devices. Each of the eight screwdrivers provided in the present case is provided for a clamping screw 24, which can be screwed through bores in the clamping part 18 into the threaded holes 23 which are provided in the cylinder head (workpiece 16) for receiving the clamping screws of the cylinder head. In the drawings, a screwdriver is provided which works together with a special clamping screw 24, the head of which is supported on the top of the clamping part 18. The screwdriver can also be provided to completely remove the clamping screw from the

Pull out J5 threaded hole 23, and it is too possible that instead of using separate clamping screws a corresponding one with a thread provided clamping part is arranged directly on the clamping device that has its axial support in this The workpieces 16 are moved into and out of the honing machine by a transport device 21 The transport device is in the embodiment in the form of simple transport rails symbolizes it can, however, be any transport device, for example chain, Roller conveyor or the like. Act.

In the transport direction 28 behind the honing machine 11 a measuring station 25 is arranged, which in the same way as the honing device a workpiece table 13 and a

Clamping part 18 carried in this way by supports 19 with clamping devices 20 is preferably the clamping device Identically designed as with the honing machine in order to create the same conditions as possible. It is but possible both with the measuring station and with the honing machine, without longitudinal movement of the table 13 get along if, for example, three honing or measuring tools are used. At the Embodiment only one measuring tool 26 is shown, which like the measuring device on the honing tool 15 works with measuring nozzles 27 arranged one behind the other and into the workpiece bores from above 17 is retractable. For clarification, measuring devices are both on a separate measuring section 25, and although here at a NachnieÖstation, as well as on Honing tool 15 itself shown This embodiment i. can in particular alternatively be used. not will.

The honing machine works; according to the following procedure

The workpiece 16 is brought into the tunnel-like receiving station on the transport device 21. the Tensioning devices 20 are put into operation and pull with a precisely predetermined tensioning force. (Torque) the workpiece 16 against the clamping part 18. The clamping force is measured so that it the The clamping force between the cylinder block and the cylinder head in the later assembly of the engine. That too Clamping part 18 is designed so that it is in its Support surface for the cylinder head and its possible inherent deformation the corresponding Properties of the part to be assembled in its place later (cylinder head) are simulated. Normally If the tightening torque for the Spannschrau- ι "> ben 24 is measured as the torque at the later assembly, however, a deviation from this torque can lead to inaccuracies in the correspondence between the conditions during honing utid compensate for later assembly. .Vi The workpiece 16 is so when it is prepared for honing, clamped on the clamping part 18 and from the Transport device 21 free. The clamping device of the honing machine simulates the state of use of the Workpiece. r>

If it proves necessary, it can be done by tensioning and releasing one or more times before the start of the honing process, the state of the final assembly can be simulated even better, in that, for example, cirates or the like resulting from the machining of the clamping surfaces during the first clamping yield, so that only the subsequent stresses accurately reproduce the final stress state. It is therefore possible to measure the shape of the bore js between these voltages via the measuring nozzles 27 to undertake. In order to carry out such a previous measurement of the bore shape, however, a The measuring station, which can correspond approximately to the measuring station 25, is connected upstream of the honing machine as a pre-measuring station be. In this, the upstream -to Clamping operations are carried out.

Due to the described tension on the honing machine The hole may get the same dimensions, roundness and cylindricity as in the Pre-processing present form deviating shape. This is now the case with the subsequent honing process balanced as necessary. Methods of short-stroke honing can be used to support the Bottlenecks or the change in the stroke limit position are used. Control can either be via the pre-measuring station described or also take place via the measuring nozzles 27 on the honing tool itself. After all workpiece bores have been machined on the workpiece by moving the workpiece table 13 are, the clamping devices 20 are released and the workpiece 16 on the transport device from the Honing machine transported.

In the exemplary embodiment, it then arrives at the re-measuring station 25, where it is repeated in the same way as is previously clamped against the clamping part 18, so that the conditions of use are again present. That Measuring tool 26 then determines whether the required values of roundness. Cylindricity and Tolc-ans achieved are. It is important that the voltage is also present during the measurement. The final measurement can be done both can be used for committee control as well as for measurement feedback to the Honstalion. It is also possible, at the honing station itself by intermittent measurement and immediate correction of the conditions to achieve an optimal bore shape during the honing process.

A workpiece is thus produced whose workpiece surfaces, which are important for later use, are as follows are processed so that they are optimal in later use, while after relaxation, i. H. as Individual part, may vary considerably from this value. Although the invention is particularly advantageous for engine parts like cylinder blocks, it is However, it can also be used on other comparable parts, especially those that are manufactured in large series are clamped together with other parts by a predetermined force during later assembly will.

In the honing machine, several honing spindles and / or honing processes that process the bore in succession can be provided, between which a relaxation and re-interruption are preferably carried out.

The tension is normally measured in such a way that that the conditions of use are present during the honing process. But that doesn't necessarily mean that the clamping forces and / or the resulting degree of deformation of the workpiece before honing exactly the same as the conditions during assembly. It may turn out, for example, that the tightening torques of the clamping screws compared to the Mcntagewert should be changed because other partial heating cJer during the honing process Forces act on the factory floor than in the operation of the Engine. It is also possible to add something to the tension forces increase to by a somewhat stronger Yerfo.νηιι; · «* der Areas to be machined to achieve a greater reduction in tension to compensate for the deformation.

For this purpose 2 sheets of drawings

Claims (7)

Patent claims: 1. Honing machine for honing workpiece bores, which after honing with other parts be clamped via clamping means, in particular for honing the bores. Cylinder blocks, on the honing machine a bracing effect corresponding to the other part the workpiece clampable part is provided, characterized in that the Clamping part (18) forms the upper support of a bridge which receives the workpiece (16) below it and which is arranged above a displaceable workpiece receiving table (13) of the honing machine (11) and that on the bridge on the tensioning means (24) acting, mechanically driven tensioning devices (20) are arranged with a predetermined clamping force. 2. Honing machine according spoke 1 with a measuring device, characterized in that the Measuring device (27) a measuring tool for the dimensions or the shape of the hole in the having tensioned state of the workpiece (16). 3. Honing machine according to one of the preceding claims, characterized in that you have a Bore measuring station (25) with a clamping part (18) and clamping devices (20) is assigned to the front the measurement for clamping can be actuated. 4. Honing machine according to claim 3, characterized in that the bore measuring station (25) is a re-measuring station with a control feedback to the honing machine (11) 5. Honing machine according to claim 3, characterized in that the drilling measuring station (25) A pre-measuring station with one clamped the shape of the J5 to be machined - workpiece surface measuring tool is. 6. Honing machine according to one of the preceding claims, characterized in that the clamping part (18) with the clamping devices (20) for machining multiple workpiece bores (17) the honing machine (I I) is movably arranged. 7. Honing machine according to one of the preceding claims, characterized in that the clamping devices (20) there are 5 screws placed on the clamping part (18).