WO2004069472A1

WO2004069472A1 - Device and method for cnc grinding camshafts, crankshafts and the like

Info

Publication number: WO2004069472A1
Application number: PCT/EP2004/000930
Authority: WO
Inventors: Georg Himmelsbach
Original assignee: Erwin Junker Maschinenfabrik Gmbh
Priority date: 2003-02-03
Filing date: 2004-02-02
Publication date: 2004-08-19
Also published as: DE10304252A1

Abstract

Disclosed is a device for CNC grinding camshafts, crankshafts and the like on a mass scale. The device comprises a control unit (2), an integrated charging device (3) and a first and second basic modular grinding unit (4,5) which are combined to form a complex. Each basic grinding unit (4, 5) comprises at least one grinding disk (6) whose axis of rotation is disposed in such a way that feed motion during grinding occurs in a substantially right-angled manner in relation to the longitudinal axis (8) of the workpiece. The charging device (3) is embodied in such a way that it slips over the basic grinding units (4,5) and contemporaneously loads them with workpieces (1) or unloads said workpieces therefrom. The grinding disks (6) and the control device (2) are embodied in such a way that the grinding process is divided up into a first grinding section in the first basic grinding unit (4) and into a second grinding section in the second basic grinding unit (5) such that the workpiece (1) is ground in the first grinding unit before it is finished in the second basic grinding unit (5) once it has been transferred thereto by the charging device (3). The grinding sections grind for essentially the same amount of time. The two grinding sections operate in a substantially simultaneous manner.

Description

Erwin Junker Maschinenfabrik GmbH February 2, 2004

J81455PCT F / Le / jr / mh

DEVICE AND METHOD FOR CNC GRINDING CAMSHAFT, CRANKSHAFT AND THE LIKE

The invention relates to a device and method for CNC grinding of camshafts, in particular with concave or hollow flanks, crankshafts and the like.

Since camshafts have at least cylindrical sections, the bearings, and non-circular sections, the cams, the devices for grinding these camshafts must be suitable for at least round and / or non-circular grinding. Known grinding machines for camshaft grinding are today CNC-controlled machines, which preferably use CBN grinding wheels. Camshafts, the cams of which have concave areas, were brought to large-scale production for large-scale production at the end of the 1980s using CNC technology and using CBN discs. The development towards high-volume production resulted from increased demand from the automotive industry in order to achieve a targeted increase in efficiency and, at the same time, a reduction in harmful exhaust gas emissions with improved / optimized charge exchange ratios. This optimization also applies to camshafts with cams without concave flank areas. The development for the large-scale production of crankshafts in a technologically and accuracy-optimized manner also results from increased demands from the automotive industry.

In addition to creating the prerequisites for mass production, it therefore plays a role in the required service life under high loads in automotive engineering the accuracy of the camshafts as well as the crankshafts play a decisive role.

From Böse, Camshaft Grinding Goes High-Tech, American Machinist, October 1988, pages 60 to 63, it is known to grind camshafts with different grinding wheels in two setups, using a large grinding wheel, which is less susceptible to wear, to pre-grind be carried out on a first machine and finish grinding is carried out by means of a small disc on a second Sc grinding machine specially designed for the use of small discs.

In accordance with the course of technical development and to increase the accuracy, it is pointed out according to DE 41 37 924 C2 that it is particularly advantageous if such camshafts are pre-ground and finished in a single clamping. First, a large grinding wheel, which is mainly used for scraping, and therefore a high amount of material is removed, and then a small grinding wheel is brought into engagement by means of which the camshaft, and in particular also the concave areas of the cams, are finish-ground.

Since camshafts are components that are manufactured in extremely large numbers, ie in large or large series, the productivity of the manufacturing process plays an increasingly important role. In the known camshaft grinding machines, it has been proposed to arrange the two different grinding wheels on separate grinding headstocks, both grinding headstocks being arranged one on top of the other according to DE 41 37 924 C2. Furthermore, grinding machines have become known in which a single grinding headstock arranged as a swivel headstock carries two different grinding wheels, the respective grinding wheel being swiveled to the workpiece and delivered to the workpiece in accordance with the grinding task currently to be carried out. Furthermore, it is from a machine from the same applicant JUCAM 6002/50 Known to use two different grinding headstocks, each of which carries a grinding wheel, which are used one after the other for the respective grinding task.

A disadvantage in terms of high productivity in large-scale production is that with all of these types of grinding, the grinding wheel that is not currently required is not in use and therefore remains unused or unproductive in a rest position.

In contrast, the object of the invention is to provide a device and a method for CNC grinding of camshafts, in particular with hollow flanks, crankshafts and the like, for large-scale production, by means of which the manufacturing effectiveness and thus the productivity of their manufacture are increased and the manufacturing process is compressed and can be carried out more clearly.

This object is achieved by a device with the features according to claim 1 or by a method with the features according to claim 12. Appropriate further training is defined in the respective dependent claims.

According to the invention, a device for CNC grinding of workpieces such as camshafts, crankshafts and the like is created in large series, which has a control device, a loading device integrated in the device and at least two modular basic grinding units connected to a complex, each with a driven grinding wheel united. This creates a double arrangement of the first modular basic grinding unit and second modular basic grinding unit, which, when optimally equipped, achieves a cycle time reduction of up to 45% through the simultaneous processing of grinding processes divided between the two basic grinding units. In addition to saving on installation space, the double arrangement according to the invention is less expensive than two separate separate grinding machines because two basic grinding units, ie grinding modules, are connected to the complex to form a single device, without all the elements of a complete grinding machine being required twice. As a result, the costs for the device according to the invention are also lower than those for two separate grinding machines.

In the device according to the invention, the respective axis of rotation of the corresponding grinding wheel is preferably arranged in one plane with the longitudinal axis of the workpiece, the grinding wheels being brought in substantially at right angles to the longitudinal axis of the workpiece. In order to achieve the desired significant reduction in cycle times, a charging device is also integrated in the device, which is designed such that the at least two modular basic grinding units can be painted over or passed over by the charging device, and preferably the charging device can load these basic grinding units simultaneously or can discharge again. "Simultaneously" should include "essentially at the same time".

The loading device integrated in the device preferably picks up a workpiece to be ground, inserts it into the first basic grinding unit, in which a defined part of the entire grinding process is carried out in defined areas of the workpiece. If necessary, during the grinding in the first basic grinding unit, the loading unit is moved in such a way that when grinding has now ended in the first basic grinding unit, a new workpiece to be ground and essentially simultaneously the workpiece ground in the first basic grinding unit can be lifted up simultaneously. This is followed by the method of the loading device in such a way that the newly picked-up workpiece to be ground is inserted into the first basic grinding unit and the workpiece that has already been ground in the first grand grinding unit and is to be transported to the second basic grinding unit is inserted into the second basic grinding unit at the same time. Both basic grinding units are thus loaded at the same time, whereby a single workpiece during the entire grinding process is contrary to the prejudice of the prior art is not being ground in a single clamping, but is unloaded from the first basic grinding unit and loaded into the second basic grinding unit.

If the workpiece is gripped by the loading device in the first basic grinding unit, it remains in the gripped position during the movement of the loading device to the second basic grinding unit and is inserted into the second basic grinding unit and clamped there accordingly. The reclamping process takes place in such a way that the workpieces are transferred from the first basic grinding unit to the second with the same radial positioning. This makes it possible that the grinding program running in the second basic grinding unit does not have to be readjusted with regard to the workpiece contour, such as the cam shape or its radial positioning, without readjustment. This also contributes to shortening the cycle time compared to the provision of two separate scraper machines.

When the workpiece has been finish-ground in the second basic grinding unit in accordance with the distribution of the entire grinding task, the loading device grips the workpiece partially ground in the first basic grinding unit and the workpiece finish-ground in the second basic grinding unit and transports the finished workpiece out of the machine for removal, whereby while the finished ground workpiece is being deposited, the workpiece picked up from the first basic grinding unit is simultaneously loaded into the second basic grinding unit, ie is clamped there. At the same time, a previously gripped workpiece to be ground is inserted into the first basic grinding unit parallel to the unloading into the receiving station and parallel to the loading of the second basic grinding unit already partially ground workpiece. By essentially loading or unloading workpieces from the respective basic grinding units at the same time, cycle time savings can already be achieved compared to individual processes in individual grinding machines. According to the invention, the grinding wheels of the respective basic grinding unit and the control device of the device are designed in such a way that on each basic grinding unit the overall grinding process to be carried out on the workpiece is carried out in a first grinding section, which is implemented in the first basic grinding unit, and in a second grinding section , which is realized in the second basic grinding unit, can be divided up in such a way that the workpiece is ground, ie partially ground, in the first basic grinding unit and then, after having been moved with the loading device into the second basic grinding unit, is finished in this. The entire grinding process is not only divided in time into the two grinding sections, but due to an intelligent design of the control device and targeted selection and use of the grinding wheels, the division is also essentially of the same length and technologically and in terms of manufacturing accuracy. According to the invention, due to the fact that a workpiece is clamped in both the first basic grinding unit and the second basic grinding unit, the first grinding section and the second grinding section on the workpieces in the first and in the second basic grinding unit run essentially in parallel.

If both grinding sections run in parallel and are essentially of the same length, this ensures that the grinding wheels are in use during the entire grinding process. As a result, non-operating times of grinding wheels are greatly reduced and high cycle time savings are achieved by means of the device according to the invention in the form of a so-called double machine. In addition to the high cycle time savings, the double machine also has the advantage that such a double machine is cheaper * than two separate individual machines.

The device according to the invention can not only be used to significantly reduce the cycle time, it also offers greater flexibility in that that both basic grinding units of the device according to the invention connected to form a complex can be used in the sense of optimizing the entire grinding process in the case of components to be newly manufactured. When using high-precision clamping devices, whereby the workpieces to be ground can preferably be clamped in the basic grinding units between centers, the high precision required for today's camshafts can easily be achieved. In comparison to the use of two individual grinding machines, there is no further loss of time in the device according to the invention, since the time otherwise required for delivering the grinding wheel not currently in use to the workpiece can be used for loading the basic grinding units by means of the loading device.

The use of a single grinding wheel per basic grinding unit is particularly preferred because, with such an arrangement, the downtimes of grinding wheels that are not currently in use are reduced to a minimum. However, it is also possible and desirable for certain applications that a grinding headstock, preferably a swiveling grinding headstock, is preferably provided for at least one basic grinding unit, which carries two different grinding wheels, so that within a modular basic grinding unit there is further greater flexibility for executing also complicated grinding processes is possible. In addition, it can be achieved that the two grinding sections can be coordinated even better with regard to the simultaneity and precision of the production, even with complicated workpieces.

When dividing the individual grinding sections according to the invention between the basic grinding units combined in the device to form a complex, the grinding sections between the first and the second basic grinding unit in particular can of course be exchanged in order to achieve approximately equally long grinding time sections which the manufacturing do not influence the accuracy of the workpiece to be ground or only negligibly.

In this context, finish grinding should be understood to mean that the workpiece is finish-ground according to a defined grinding task. Finishing grinding can also be just a rough grinding process, the distribution of the grinding process between the modular basic grinding units being carried out in such a way that part of the grinding process in certain areas of the workpiece in the first basic grinding unit and the other part of the grinding process for further or the same areas of the workpiece in the second basic grinding unit. Of course, it is also possible to combine more than two basic grinding units to form a complex for the device according to the invention. The loading device integrated in the device is then to be adapted in accordance with its size to sweep over all the basic grinding units.

The loading device which can be moved within a working space / a housing of the device according to the invention has such a length or is designed such that it has a feed station in which the workpieces to be ground are stored and from which the loading device picks up the workpieces to be ground, and a receiving device passes over in which the finished workpieces - in the sense of the above definition for finish machining - can be held. Picking up workpieces to be ground and loading the first basic grinding unit as well as moving a workpiece from the first basic grinding unit to the second basic grinding unit and unloading a workpiece that has been finished ground in the second basic grinding unit take place simultaneously according to the design of the loading device, which means additional cycle times can be saved. The loading device can be moved so far out of the complex towards the feed station on the one hand and towards the receiving station on the other hand that the workpieces can be picked up or are discardable. For this purpose, the loading device has at least three holding elements for workpieces. Three holding elements are preferred above all if the complex of the device according to the invention has two basic grinding units.

With regard to the overall arrangement, it is preferred that the first modular basic grinding unit and the second modular basic grinding unit are arranged one behind the other in the longitudinal direction of the workpieces to be ground. Such an arrangement is particularly preferred that the longitudinal axes of the workpiece are aligned with one another.

However, according to a development of the invention, it is also possible for the first modular basic grinding unit and the second modular basic grinding unit or the modular grand grinding unit to be arranged one behind the other transversely to the longitudinal direction of the workpieces to be ground. The preferred arrangement depends on the space available in the respective production hall. Because the device according to the invention is constructed in a modular manner, it is therefore easily possible to arrange the modular basic grinding units either in the longitudinal direction of the longitudinal axes of the workpiece or one behind the other transversely to their longitudinal axis. In any case, the individual parts of the complex of the device according to the invention are provided with a separation point at which the individual grand grinding units can be dismantled from one another, which is particularly useful for transport or possibly for repair purposes.

In order to be able to solve different grinding tasks for a workpiece and to increase the flexibility of the device according to the invention, it is further preferably provided to use different grinding wheels, in particular CBN, diamond and / or corundum grinding wheels, in the first and in the second basic grinding unit. If, according to a preferred development, each or only one of the basic grinding units has a grinding headstock equipped with two grinding wheels, the respective one can Swivel grinding headstock itself can be equipped with different grinding wheels. This makes it even easier to divide up the grinding task or the grinding process according to the invention in such a way that the grinding time segment that takes place in the first basic grinding unit is approximately as long as the grinding time segment that takes place in the second basic grinding unit.

Each of the basic grinding units preferably has three CNC-controlled axes, the X axis being used for positioning the grinding wheel, the Z axis being used for the relative movement of the grinding wheel relative to the workpiece, and the C axis being used for rotating the workpiece. In particular, the fact that each basic grinding unit also has a CNC-controlled C-axis offers a high flexibility of the device according to the invention for a wide variety of grinding tasks within the framework of the teaching according to the invention.

The loading device is preferably designed or has such a length that it opens a respective cover of an opening in a housing of the device for gripping a workpiece from the feed station or for depositing a finished, ground workpiece into the receiving station. The covers in the opening of the housing of the device are preferably self-closing after the charging device has been completely retracted into the housing.

Calculations have shown that, in addition to the considerable reduction in cycle time and the reduced space requirement for identical grinding tasks and identical grinding start, the device according to the invention can lead to a reduction in machine costs of up to 25% compared to individual machines. One of the reasons for this is that the double machine according to the invention preferably manages with a single hydraulic or pneumatic system, a single coolant supply and a single control unit as well as a single control cabinet connected to it. By dividing the grinding process into grinding sections, which are carried out in different basic grinding units, the programming effort is further reduced in that less effort in terms of collision avoidance, which would otherwise be required for two different grinding headstocks, has to be carried out, since more manageable grinding processes take place in each of the basic grinding units.

Furthermore, an advantage of the device according to the invention is that due to the fact that only raw parts are fed in, for example, the individual device, i.e. the only complex in the sense of the grinding task only delivers parts that have already been ground, so that intermediate storage or buffers, which are required between individual ScMeifi machines in conventional production centers, are no longer necessary, so that intermediate transport and buffers are no longer necessary.

Because of the high flexibility of the device according to the invention, it is of course also possible for pre-grinding operations in the sense of scrap grinding to be carried out in one or a part of the basic grinding units, while another or further basic grinding units are only equipped for carrying out finish or finish grinding operations can be or can be.

Since grinding tasks can be exchanged almost arbitrarily between the individual basic grinding units, as long as the grinding periods that run to the respective basic grinding units are essentially the same size or length, the respective grinding time segments can be carried out more easily with optimized grinding parameters, since in the respective one Basic grinding unit can be used to run any technology parameters that are optimally adapted to the cutting process. The axis of the respective grinding wheel is preferably arranged in one plane with the longitudinal axis of the workpiece. In such a case, the non-circular surface to be ground, for example a cam, is ground in the sense of a plunge movement of the grinding wheel. However, it is also possible that the grinding, in particular grinding of cylindrical surfaces, takes place in such a way that a small clearance angle which is only in the minute range is generated by the fact that the axis of rotation of the grinding wheel is spatially inclined by the clearance angle with respect to the longitudinal axis of the workpiece. Finally, it is also possible that if the axis of rotation of the grinding wheel and the longitudinal axis of the workpiece lie in one plane, the axis of rotation on the respective grinding wheel is inclined in the plane such that certain surfaces can also be ground with a conically profiled grinding wheel without a direct infeed in one right angle to the workpiece longitudinal axis.

According to a further aspect of the invention, a method for grinding workpieces such as camshafts, in particular with concave flank regions of the cams, crankshafts and the like, is created in large series production. The method is carried out on a device which has at least two modular basic grinding units connected to form a complex. In the usual manner, which is familiar to the person skilled in the art, the basic grinding units have a grinding headstock, a workpiece headstock and a tailstock, which are arranged on a machine bed. According to the method according to the invention, the workpieces are partially ground in one basic grinding unit, then reclamped in the other basic grinding unit with the same radial positioning of the workpiece or cam of the camshaft and finally finished there. The basic grinding units are loaded and controlled in such a way that the partial grinding and the final grinding take substantially the same length of time and run in parallel on the workpieces clamped in the basic grinding units, in particular camshafts. The cycle time savings compared to two or more individual ScMeifin machines results above all This is due to the fact that the grinding is divided into the partial grinding and the finishing grinding in such a way that both grinding sections are essentially of the same length and run in parallel on the workpieces clamped in the respective basic grinding units. The basic grinding units are preferably also loaded and unloaded with the workpieces in parallel.

Further advantages and details of the invention will now be explained in detail in connection with the description of exemplary embodiments with reference to the accompanying drawing. It shows:

Fig.l: a schematic layout plan of a device according to the invention;

2: a top view of the cylindrical grinding units connected to form a complex;

3: a top view according to FIG. 2, double headstocks being provided in each case;

4: a front view of the device according to the invention; and

5: a charging device for the device according to the invention.

In Figure 1, a floor plan is shown in principle in plan view of the device according to the invention. In the device, two modular basic grinding units 4, 5 are connected in a modular design to form a complex. A complex is to be understood to mean that the two modular basic grinding units 4, 5 are connected to one another via a separating point 26, so that a unitary device, at least for round and / or non-round CNC grinding of camshafts or crankshafts, is significantly reduced Cycle time compared to two separate individual machines is possible. The separation point 26 is designed so that for the purpose of transportation or maintenance or repair, both modular basic grinding units 4, 5 can be separated from one another. In the case of basic grinding units 4, 5 combined to form the complex, the total space required by the device according to the invention is less than if two completely separate machines are set up. The device is brought together to form the complex in such a way that the charging device 3 integrated into the device (see FIG. 4) sweeps over both basic grinding units 4, 5. This means that both basic grinding units 4, 5 can be loaded or unloaded simultaneously with the loading device.

A control device in the form of a control cabinet is shown schematically in the upper part of FIG. This control cabinet serves for the electrical supply and also contains elements of the control device 2. The control device 2 includes an input and display device which is shown on the left by an operator 20. This input and display device is attached to an arm in the area of the separation point 26, which is pivotally attached. As a result, the input and display device can be pivoted by the operator 20 to the respective modular basic grinding unit 4 or 5, on which the operator either wants to make an entry or to receive a display. The advantage of the device according to the invention is also that the space requirement is additionally reduced by the fact that only a single control device 2 is required for the complete device, which according to FIG. 1 is constructed from the two modular basic grinding units 4, 5. Likewise, only a single hydraulic and / or pneumatic supply is required. Likewise, the coolant supply for both basic grinding units 4, 5 takes place via a central coolant station (not shown). For a single machine, for example, a control device in the form of a control cabinet approximately in the size shown in FIG. 1 above is required. In addition to the saving in space, the device according to the invention therefore also involves considerable savings in installation and investment costs. According to the arrangement according to FIG. 1, the two basic grinding units 4, 5 are arranged one behind the other in the sense of the production sequence, the dash-dotted line identifying the longitudinal axis of the workpiece so that the longitudinal axes of the workpiece of the two modular basic grinding units are aligned with one another in this arrangement. Each modular basic grinding unit is arranged on a machine bed 21, which forms a uniform connection of the two basic grinding units 4, 5 according to FIG. 1 via the separation point 26. Of course, it is also possible if the transport and installation or assembly conditions make it possible to arrange both modular basic grinding units on an undivided machine bed 21, in which case there is then no separation point.

FIG. 2 shows a top view of the device according to the invention, which shows in more detail than in FIG. 1 the arrangement of the modular basic grinding units 4, 5 connected to form a complex. Both modular basic grinding units 4, 5 are connected to one another at the separation point 26 and each have a grinding headstock 35 which carries a grinding spindle with a grinding wheel 6 which has an axis of rotation 7. The grinding headstock 35 is fed through an X-CNC axis 18 at right angles to a workpiece 1. The grinding headstock 35 is arranged on the machine bed 21, which also carries a workpiece headstock 22 and a tailstock 23. The workpiece 1, in this case a camshaft, is clamped between the workpiece headstock 22 and the tailstock 23. The clamping can take place between peaks; however, it is also possible for the workpiece headstock to chuck a chuck in order to transmit the corresponding rotary movement from the drive of the workpiece headstock to the workpiece 1 thus set in rotation. The workpiece 1 is arranged at right angles to the infeed of the grinding wheel 6 with respect to its workpiece longitudinal axis. On the machine bed 21, the workpiece headstock 22 and the tailstock 23 are separate or, when the workpiece 1 is clamped, via a Z-CNC axis 19 relative to the position of the grinding wheel 6 displaceable so that the grinding wheel 6 can grind the cams arranged next to one another in the longitudinal direction of the camshaft.

The camshaft is mounted between the workpiece headstock 22 and the tailstock 23 by means of steadies 24, in particular in order to increase the accuracy of the camshaft and, in conjunction therewith, to optimally introduce the required grinding forces. It is understood that the steady rest bearing 24 is advantageously used in particular in the case of long workpieces, whereas in the case of short workpieces which have a sufficiently high rigidity, a steady rest storage is not absolutely necessary.

3 shows a view of the device according to the invention according to FIG. 2, but with a swiveling grinding headstock 17 for the respective basic grinding units 4, 5 instead of the grinding headstock 35 according to FIG. 2. The basic structure of the device according to the invention corresponds to the two modular basic grinding units connected to the complex 2. To increase flexibility, however, a swiveling grinding headstock 17 is provided in each of the basic grinding units, which carries two grinding wheels 6 each. The swiveling grinding headstock 17 has a swiveling axis 25, the possible swiveling movement about the swiveling axis 25 in FIG. 3 being identified by the double arrow arranged around the swiveling axis 25.

For the most common cases of application, the respective grinding wheel 6, which has been brought into engagement, is also fed in at right angles to the longitudinal axis 8 of the workpiece, even in the case of the swiveling grinding headstock, which offers significantly greater flexibility. It goes without saying that, however, a grinding wheel can also be fed in at an angle different from 90 ° to the workpiece, provided that the grinding task requires this. The swiveling grinding headstock offers the prerequisite for this because each grinding wheel can be brought into engagement with workpiece 1 at any angle between 0 ° and 90 °. Although there is only ever one grinding wheel 6 in engagement with the workpiece 1 in a swiveling grinding headstock with two grinding wheels in each of the basic grinding units, the presence of two generally different grinding wheels in each basic grinding unit 4 or 5 offers the possibility of that the grinding steps required as part of the overall production of the camshaft are easier to divide between the basic grinding units so that the grinding section in the first modular basic grinding unit is essentially as long as the grinding section in the second modular basic grinding unit. The division can be carried out in such a way that in the first grinding unit only pre-grinding or roughing is carried out, whereas in the second basic grinding unit only finish-grinding or finish-grinding is carried out. However, it is a prerequisite that the grinding sections in both basic grinding units 4, 5 are of almost the same length. Of course, it is also possible within the scope of the invention to divide both the roughing or scale grinding as well as the finishing or finishing grinding between the grand grinding units in such a way that both part of the roughing or scale grinding and part of the finish - or finishing grinding is carried out in each of the basic grinding units, so that a particularly good match of the duration of the grinding sections in the two basic grinding units can be achieved. However, finish grinding is not always to be understood as finish grinding. Rather, the device according to the invention can also be used to carry out, for example, only a prefabrication task related to the complete finishing of the workpiece, for example roughing and semi-finishing grinding processes being divided between the modular basic grinding units in such a way that the two grinding time segments are of approximately the same length. For the purposes of this application, finish grinding means completing the respective grinding task.

FIG. 4 shows a basic front view of the device according to the invention, in which two modular basic grinding units are connected in series to form a complex in the direction of production. Position of the charging device 3 is located. For the device according to the invention with two modular basic grinding units, ie the first modular basic grinding unit 4 and the second modular basic grinding unit 5, the charging device 3 has three holding elements 14, 15, 16. The device shown in FIG. 4 has a feed station 9 and a receiving station 10. If the device according to the invention is now put into operation, the loading device 3 with its holding element 14 receives a tool to be ground from the feed station 9, the loading device being designed in such a way that the holding elements can execute a lifting movement 28. When the workpiece is picked up and raised by means of the holding element 14 from the feed station 9, the charging device 3, which is completely integrated in the device according to the invention, that is to say arranged in the housing 13 of the device, moves along its displacement path indicated by the double arrow 27 into the device until it is connected with the Holding element 14 held workpiece is arranged exactly in the first modular basic grinding unit, wherein it is then lowered by the loading device 3 to such an extent that it can be clamped between the workpiece headstock and the tailstock (not shown in FIG. 4).

The Hdteeinrichtung 3 now moves along the displacement path 27, the holding element 14 is again so far out of the housing 13 of the device out exactly above the receptacle position for a new workpiece in the ^'feeding station. 9 During the movement of the loading device 3 out of the device to the feed station 9, the workpiece is already ground or partially ground in the first basic grinding unit as part of the division of the overall grinding process, that is to say within the scope of the first grinding section. When this first grinding section has ended, the holding device with the holding element 14 grips a new workpiece from the feed station 9 and at the same time the workpiece partially ground in the first basic grinding unit in the first basic grinding unit with the holding element 15 and then travels along the displacement path 27 back into the device, and so far until the partially held with the holding element 15 Ground workpiece exactly above the clamping point between the workpiece headstock 22 and the tailstock 23 of the second basic grinding unit and the workpiece newly taken up with the holding element 14 is located exactly above the clamping point between the workpiece headstock and the tailstock of the first basic grinding unit 4. At the same time, both workpieces are then unloaded into the respective basic grinding unit 4, 5 and clamped accordingly. From gripping the workpiece in the first basic grinding unit to reclamping the workpiece in the second grand grinding unit, the workpiece does not change its position in the holding elements. This ensures that the radial position of the workpiece, such as the camshaft or cams in the camshaft after reclamping in the second basic grinding unit, is the same as that at the time the workpiece was gripped in the first basic grinding unit by the corresponding holding element of the loading device. As a result, readjustment between the radial position of the workpiece to be ground and the control program, ie grinding wheel to be brought into engagement with the workpiece, is no longer necessary after reclamping into the second basic grinding unit.

After loading, the charging device 3 remains in this position until both essentially identical cutting time periods have ended. This means that in the first basic grinding unit 4, the workpiece 1 is partially ground during the first grinding section, while the workpiece 1 previously ground in the first basic grinding unit 4 is finished in the second basic grinding unit 5 at the same time. Both grinding time sections are essentially of the same length, so that both grinding sections are ended essentially at the same time. When both grinding sections are finished, the holding element 14 simultaneously grips a new workpiece from the feed station 9, with the holding element 15 the partially ground workpiece from the first basic grinding unit 4 and with the holding element 16 the finished workpiece from the second basic grinding unit 5, via which Lifting movement 28 raised and along the displacement path 27 as far move total 27 to the receiving station 10 until the finished workpiece 1 can be reliably placed in the receiving station 10. At the same time, the holding element 15 loads the workpiece 1 partially ground in the first basic grinding unit 4 into the second basic grinding unit 5, and likewise simultaneously the previously newly received workpiece 1 is loaded into the first basic grinding unit 4 by means of the holding element 14. The grinding process in the device according to the invention now again takes place in parallel in the first basic grinding unit 4 and the second basic grinding unit 5 in accordance with the substantially identical grinding time segments.

In this way, by reclamping the workpiece 1 from the first basic grinding unit 4 to the second basic grinding unit 5, the cycle time is considerably shortened because, on the one hand, the grinding processes are coordinated with one another in such a way that the grinding times are approximately the same length, and because others, in addition to the time-parallel loading of the respective basic grinding units in the basic grinding units, is ground in parallel.

So that the coolant used in the device 13 for the grinding process and, on the other hand, ground particles cannot leave the immediate area of the device for safety reasons, the device is arranged in a housing 13, as is also the case with separate scapping machines. However, so that the charging device 3 integrated in the device can move out of the housing 13 both into the area of the feed station 9 and into the area of the receiving station 10, openings 11 provided with covers 11, 12 are provided in the housing 13 at the passage points of the charging device 3 intended. If, for example, the charging device 3 emerges from the housing 13 in the direction of the feed station 9, the charging device 3 itself opens the cover 11. When the charging device 3 is retracted into the housing 13, the cover 11 closes automatically. This applies equally to the cover 12 in connection with the discharge of the charging device 3 from or its entry into the housing on the side of the receiving station 10.

FIG. 5 shows a partially sectioned side view of an exemplary embodiment of a loading device 3. The loading device 3 has a longitudinal beam 30, which is designed as a hollow profile and extends over a length that extends at least from the feed station 9 or the receiving station 10 to both modular ones Basic grinding units 4, 5 are sufficient. A rail 31 is attached to the longitudinal beam 30 and is profiled for guidance, roller guides 32 being arranged on the profile edges. The roller guides 32 are in turn attached to a holder 33, on which holding struts 34 are fastened, on which the actual holding elements 14, 15, 16 are located. The charging device thus has three holding struts 34, each holding strut 34 carrying a holding element 14 or 15 or 16. The holding elements 14, 15, 16 are designed such that the workpiece 1 can be gripped, held and transported in the manner of pliers. The holding forces are sufficiently high so that after gripping the workpiece, its radial positioning is fixed in the second basic grinding unit 5 until it is clamped.

The lifting movement 28 of the loading device 3 is realized via the lifting movement of the holding struts 34 in that the upper end of the holding struts 34 is connected to an eccentric 29 via a crank member. Upon rotation of the eccentric 29, the attractive movement 28 of the holding struts 34 and thus of the holding elements 14, 15, 16 and thus of the workpiece 1 is effected. In the longitudinal direction of the loading device, the holding struts 34 or the holding elements 14, 15, 16 are evenly spaced, the distance between adjacent holding elements corresponding to the distance between the clamping position of the workpiece 1 between the first basic grinding device 4 and the second basic grinding device 5. This means that the distance between the feed station 9 or the point of the feed station at which the workpiece 1 is gripped by it, and the first basic grinding unit 4, the distance between the two Basic grinding units 4, 5, ie the clamping position of the workpiece in these grand grinding units, corresponds. Likewise, the distance between the second basic grinding unit 5 and the receiving station 10 is the same as the distance between the first 4 and the second basic grinding unit 5. This modular design of the loading device 3 and the corresponding arrangement of the feed station 9, first basic grinding unit 4, and second basic grinding unit 5 and receiving station 10, the simultaneous loading and unloading of different locations of the device by means of the charging device 3 is possible.

LIST OF REFERENCE NUMBERS

1 workpiece

2 control device

3 charging device

4 first modular basic grinding unit

5 second modular basic grinding unit

6 grinding wheel

7 axis of rotation of the grinding wheel

8 workpiece longitudinal axis

9 feed station

10 recording station

11, 12 Cover for opening in the housing

13 housing

14, 15, 16 holding elements of the loading device

17 Swiveling grinding headstock for two grinding wheels

18 X axis

19 Y axis

20 operators

21 machine bed

22 workpiece headstock

23 tailstock

24 steady rest

25 Swivel axis swivel grinding headstock

26 separation point

27 Movement of the loading device

28 Loading device lifting movement

29 eccentrics

30 side members

31 rail

32 roller guide

33 holders 34 support strut

35 grinding headstock for one grinding wheel

Claims

Erwin Junker Maschinenfabrik GmbH February 2, 2004 J81455PCT F/Le/jr/mh P atent claims

1. Device for CNC grinding workpieces (1) in the form of camshafts, crankshafts and the like in large series with a control device (2) and a loading device (3) integrated into the device, the device having at least a first (4) and a second modular basic grinding unit (5) connected to form a complex, each with at least one driven grinding wheel (6), the respective axis of rotation (7) of which is arranged in such a way that during grinding

Delivery takes place essentially at right angles to the longitudinal axis (8) of the workpiece, the loading device (3) being designed in such a way that the large grinding units (4, 5) can be painted over and these can be loaded with workpieces (1) or unloaded from them at the same time, and the grinding - Discs (6) of the respective basic grinding unit (4, 5) and the control device

(2) are designed so that the grinding process for the workpiece (1) can be divided into a first grinding section in the first basic grinding unit (4) and a second grinding section in the second basic grinding unit (5) so that the workpiece (1) in the first basic grinding unit (4) is ground and then finished in the second basic grinding unit (5) after being transferred to the loading device (3), the grinding sections have essentially the same grinding time and run essentially in parallel time.

Apparatus according to claim 1, in which the loading device (3) further sweeps over a feed station (9), from which the workpieces (1) to be ground can be removed, and a receiving station (10), into which the finished workpieces can be deposited, where the loading device (3) can be moved out of the complex to such an extent that the workpieces (1) to be ground can be picked up by the feed station (9) and loaded into the first basic grinding unit (4) as well as the finished ground workpiece (1) from the second basic grinding unit ( 5) can be unloaded at the same time and placed in the receiving station (10).

3. Device according to claim 2, in which the loading device (3) is designed such that it is used to grip a new workpiece (1) from the feed station (9) or to place a finished workpiece (1) into the receiving station (10). a respective cover (11, 12) opens an opening in a housing (13) of the device.

4. Device according to one of claims 1 to 3, in which the loading device (3) has at least three holding elements (14, 15, 16) for workpieces

(1).

5. Device according to one of claims 1 to 4, in which the first (4) and the second modular basic grinding unit (5) are arranged one behind the other in the longitudinal direction of the workpieces (1) to be ground, in particular with aligned longitudinal workpiece axes (8).

6. Device according to one of claims 1 to 4, in which the first (4) and the second modular basic grinding unit (5) are arranged one behind the other transversely to the longitudinal direction of the workpieces (1) to be ground.

7. Device according to one of claims 1 to 6, in which different grinding wheels (6), in particular CBN, diamond and / or corundum grinding wheels, can be used in the first (4) and the second basic grinding unit (5).

8. Device according to one of claims 1 to 7, in which at least one basic grinding unit (4 or 5) has a grinding headstock (17) equipped with two grinding wheels (6), which is designed in particular as a swivel grinding headstock.

9. Device according to one of claims 1 to 8, in which the basic grinding units (4, 5) are 3-axis CNC controlled, the three axes being the X-axis (18) for grinding wheel delivery, the Z-axis ( 19) for the relative movement of the grinding wheel to the workpiece and the C axis for the workpiece rotational movement.

10. Device according to one of claims 1 to 9, in which the axis of rotation (7) of the respective grinding wheel is arranged in a plane with the longitudinal axis (8) of the workpiece.

11. Device according to one of claims 1 to 10, which is designed so that concave flank areas on the workpiece can be ground.

12. Method for grinding workpieces such as camshafts, in particular with concave flank areas of the cams, crankshafts and the like in large-scale production on a device having at least two modular basic grinding units connected to form a complex, in which workpieces are partially ground in one basic grinding unit, into the other basic grinding unit are clamped with essentially the same radial positioning of the workpieces and finished there, with the large grinding units being loaded and controlled in such a way that the partial grinding and the finish grinding take essentially the same amount of time and take place in parallel on the workpieces clamped in the basic grinding units.

13. The method according to claim 11, in which the large grinding units are loaded and unloaded with workpieces at the same time.