DE20009102U1 - Alignment device - Google Patents

Description

40rts/228699

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BARTELS, Hans Phys.

BARTELS, Martin Dipl.-Ing.

CRAZZOLARA, Helmut Dr.-Ing. Dipl.-Ing.

9 February 2000/4008

Sauter Precision Mechanics GmbH, Carl-Zeiss-Str.7, 72555 Metzingen

Alignment device

The invention relates to an alignment device for the relative position adjustment of a tool holder with respect to a tool holder receptacle in machine tools in the form of a pivoting movement with an alignment part that interacts with an adjustment part. 5

Tool holders, such as spindle heads, with drivable machining tools are installed in so-called turrets of lathes, for example to enable off-center machining of turned parts on a lathe as a machine tool. The interface between the spindle heads and the tool disk of the tool turret is defined by DIN 69880-11 (September 94 edition, p.305ff). For spindle heads where the tool axis of the drivable cutting tool is identical to the center axis of the mounting hole according to the above-mentioned DIN standard, alignment for the cutting tool is not necessary. However, alignment is required for spindle heads where the tool axis is not identical to the center axis of the mounting hole according to the DIN standard mentioned. In these cases, the tool tip must first be aligned with the corresponding axis of the machine tool, in particular the lathe, for precise machining.

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With the help of the mounting hole according to the above-mentioned DIN standard, a tool holder, for example in the form of a spindle head, can be centered in one axial direction, but not to another axis running perpendicular to it. Different alignment devices have therefore already been proposed. In one type of known alignment device according to DE 39 29 802 C1, the tool holder has two diametrically opposed adjusting screws as adjustment parts, which together act on an alignment part that is arranged on the tool holder holder for the tool holder. This solution has the disadvantage that each tool holder has to be adjusted in the inserted position using the adjusting or adjusting screws each time it is inserted into the associated tool holder holder, since if the tool holder is removed and inserted several times, changes to the alignment device occur, which lead to inaccuracies. The alignment process using two separately arranged adjusting screws is also not particularly easy to handle and is correspondingly time-consuming.

In order to eliminate the disadvantages of this prior art, it has already been proposed in DE 195 48 151 A1 to provide, as an alignment device, respective alignment parts on both the tool holder and the tool holder receptacle, which, when connected to one another, engage with one another as form-locking elements without play; the precise, play-free engagement alone requires a high level of machining effort when producing the known alignment device, so that this solution is very expensive.

DE 31 50 355 C2 discloses a tool holder insert, in particular for boring bars, with a shaft-shaped tool holder for a

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a cutting insert with an adjusting sleeve screwed onto an external thread of the tool holder, which rests with a flange on one side of a stationary collar ring, and with a spring ring placed on the adjusting sleeve, which rests on one side of the collar ring and on the other side on a collar-shaped stop on the adjusting sleeve. The spring ring ensures axial freedom of play between the components. With this known axial feed device, a relative position adjustment in the form of a swivel movement for tool holders cannot be achieved. Furthermore, the known arrangement is complicated and expensive to manufacture due to the variety of parts. It is also difficult to handle.

EP 0 962 280 A2 discloses an alignment device of this type, in which the adjustment part is provided with a housing in which a guide part for the alignment part is guided so as to be longitudinally displaceable against the effect of a force accumulator, and in which the guide part can be controlled via an actuating part. This makes it possible to create a functionally reliable alignment device with just a few structurally simple components, and it is possible to dispense with highly precise, cost-intensive fits between the alignment part and the adjustment part. Furthermore, the adjustment and alignment process can be carried out effectively via a single actuating part, which makes handling the alignment device on the processing machines much easier, particularly during later operation. With the known alignment device, the swivel adjustment movement for the relative position adjustment between the tool holder and the tool holder holder can be carried out in the same actuating direction and in the same actuating direction, so that an exact, sensible alignment of the drive axis with the machine tool basic axes, for example the Z axis, is possible. Despite the very

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Due to the lack of precise alignment, inaccuracies can occur, particularly in high-precision machining processes, which are difficult to compensate for using the known compensation device.

Based on this prior art, the invention is therefore based on the object of creating an alignment device which, in addition to the advantages of the generic alignment device, also enables high-precision machining in border areas. This object is achieved by an alignment device with the features of claim 1.

Because, according to the characterizing part of claim 1, an adjustment device is provided for pre-positioning the alignment part in a predeterminable adjustment plane for the tool holder holder, the alignment device according to the invention can be pre-positioned in a zero position before it is actually put into operation, which establishes a precisely defined reference plane for the tool holder holder or later for the tool holder with the drivable machining tool. If such a zero position is set via the adjustment device, it is maintained and, starting from this zero position, the obvious relative position adjustment between the tool holder and the tool holder holder takes place in order to achieve precise alignment in the respective machining axis. There can then no longer be a lateral offset between the desired position of the alignment device and the tool holder holder or the tool holder, as is the case with some of the known solutions, with the usual consequence that the compensation device acting in the swivel direction of the tool holder leads to unwanted machining tolerances via the lateral position offset mentioned, particularly in high-precision machining processes.

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In a particularly preferred embodiment of the alignment device according to the invention, the alignment part is designed in the form of an eccentric bushing, which has two bushing parts arranged eccentrically offset from one another, of which one bushing part is rotatably guided in the tool holder receptacle and the other bushing part is enclosed by the adjustment part. By implementing the adjustment device using an eccentric bushing, a cost-effective solution for a high-precision compensation device is achieved, and an adjustment process via the eccentric bushing is achieved quickly and easily, so that assembly and maintenance processes are reduced in terms of effort. The adjustment process from eccentric bushing to tool holder receptacle in relation to the predeterminable adjustment plane is preferably carried out using an adjustment gauge, which enables precise alignment with the adjustment plane. The adjustment gauge can be adapted to the respective tool turret or machine tool arrangement and standardized.

Further advantageous embodiments of the alignment device according to the invention are the subject of the subclaims.

In the following, an embodiment of the alignment device according to the invention is explained in more detail with reference to the drawing. They show in a basic and partially not to scale representation the

Fig. 1 is a longitudinal section through a tool holder

tool holder arranged in the form of an angle

spindle head;

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Fig.2 a partial section I - I along the section line I - I in Fig.1 and

otherwise a top view of the angle spindle head according to Fig.1;

Fig.3 in enlarged view the in Fig.1 and 2 in section

alignment device shown;

Fig.4 and 5 on a scale of 3:1 a longitudinal view and a longitudinal section through the adjustment device of the alignment device according to Fig.1 to 3;

Fig.6 in scale 1 : 5 a top view of the eccentric bushing

designed adjustment device according to Fig.4 and 5.

The alignment device is used for the relative position adjustment of a tool holder 10 with respect to a tool holder receptacle 12 in machine tools (not shown), in particular lathes. The tool holder 10 is a so-called angle spindle head with a first drive axis 14, which drives a second drive axis 16 running at right angles to it for driving a cutting tool (not shown in more detail). The cutting tool in question can be inserted in the usual and therefore not described in more detail manner via the tool receptacle 18, which can be driven by the drive axes 14, 16 for a machining process. The first drive axis 14 is rotatably guided in a tool holder shaft 20, which is provided on the outer circumference in the usual way with a toothing 22 (Fig. 2). If the tool holder 10 is inserted into the associated position via its tool holder shaft 20, the tool holder 10 can be rotated in the same way.

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arranged circular receptacle of the tool holder receptacle 12, the corresponding toothing of a clamping piece 24 according to a position according to Fig.2 with its corresponding toothing 26 engages in the toothing 22 of the tool holder shaft 20 and thus fixes the angle spindle head to the tool holder receptacle 12. To release the clamping piece 24, it is moved back in its longitudinal axis 28, whereby the toothings 22, 26 come out of engagement with one another and the tool holder 10 is released.

In a lathe, either the first drive axis 14 can run along the so-called Z-axis of the lathe and thus the second drive axis 16 is at a right angle to it, or the arrangement of the tool holder 10 is such that the second drive axis 16 is aligned parallel to the Z-axis of the lathe and the first drive axis 14 runs in a vertical direction transverse to the Z-axis. In order to avoid machining inaccuracies, the alignment device is provided with an alignment part 30 which interacts with an adjustment part designated as a whole by 32. As shown in particular in Fig. 3, the adjustment part 32 has a guide part 36 for the alignment part 30 which can be moved against the action of a force accumulator 34, wherein the guide part 36 can be controlled via an actuating part 38.

As shown in particular in Fig. 1, the alignment part 30 is fixedly arranged on the tool holder receptacle 12 and the adjustment part 32 is in turn fixedly arranged on the tool holder 10. The adjustment part 32 is provided with a receptacle housing 40 in which the guide part 36 is guided in a longitudinally displaceable manner in the form of a sliding block 42, which has an engagement point for the alignment part 30. The energy accumulator 34 is formed from at least one disc spring or disc spring packages arranged one behind the other. This

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As shown in particular in Fig. 3, they engage with one free end on one side 44 of the sliding block 42 and are supported with their other end on the inside of the receiving housing 40. To form a defined contact surface for the energy storage device 34 in the form of the disc spring assembly, the sliding block 42 has a shoulder 46 at the associated end, the shoulder-like extension being at least partially encompassed by the disc spring assembly. However, the shoulder 46 is in any case at such a distance from the inside of the receiving housing 40 that the free spring travel of the disc spring assembly is not impeded. Furthermore, the shoulder 46 provides a stop option against the receiving housing 40 in the event of excessive stress and failure of the energy storage device 34.

The actuating part in the form of an actuating screw 50 engages on the other side 48 of the sliding block 42, which is provided with an internal hexagon recess for the engagement of an actuating tool (not shown in detail), for example in the form of an internal hexagon key. The actuating screw 50 is guided with its external thread 52 in an internal thread 54 of the receiving housing 40 so that it can be screwed in and out and, as a separate component, abuts with a stop part 56 on the other side 48 of the sliding block 42, which is pressed against the stop part 56 of the actuating screw 50 under the action of the energy accumulator 34. The internal thread 54, the free end of which opens into the environment, is cut into the receiving housing 40 to such a length that the intended entire pivoting path for the second drive axis and thus for the tool holder 10 is achieved.

The sliding block 42 has a central bore 58 as an engagement point, the diameter of which is larger than the diameter of the alignment part 30 in

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Form of a pin-like eccentric bushing 60 which, as shown in particular in Fig. 1, is received with a precise fit in a fitting bore 62 in the tool holder receptacle 12. Within the central bore 58, in turn, a stop surface 64 is provided for the eccentric bushing 60, wherein the relevant stop surface 64 is part of a stop screw 66 which passes through the center of the plate spring assembly and is screwed into the sliding block 42. The free end of the stop screw 66 is loosely guided in the wall of the receiving housing 40 and can also be secured via a conventional adhesive connection within the internal thread of the sliding block 42. At the free end of the stop screw 66 there is also an engagement point for an operating tool (not shown) with which the stop screw 66 can be tightened within the sliding block 42 in order to reduce the free space within the central bore 58 of the sliding block 42.

An anti-twisting device 70 (Fig. 3) is provided so that the sliding block 42 cannot twist within its guide 68 in the receiving housing 40 during such an adjustment process. The anti-twisting device 70 has a so-called grub screw 72, which can be screwed into the receiving housing 40 and with one of its free front ends engages in a longitudinal groove 74 of the sliding block 42. This provides an effective anti-twisting device 70 and also ensures that the receiving housing 40 can still be moved longitudinally relative to the sliding block 42. The grub screw 72 can also be permanently fixed within the receiving housing 40 using a conventional adhesive connection. The housing 40 has a flange-like extension 76 on both sides in the area of engagement of the grub screw, through which a fixing screw 78 passes, which serves for the subsequent fixing of the adjusting part 32 on the tool holder 10 (see Fig.2). In order to

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In order to achieve a certain tolerance compensation, it is provided that the fixing screws 78 each engage in enlarged holes 80 within the flange-like extensions 76. The distance between the fixing screws 78 can therefore be varied in this way. 5

As Fig. 1 also shows, the alignment part 30 protrudes in a centered position over the actual support surface 82 of the tool holder receptacle 12 and can be gripped by the adjustment part 32 in the extension of the contact surface 84 of the tool holder 10 for engagement. The contact surface 82 and the contact surface 84 are worked in such a way that an exact plane-parallel contact of the tool holder 10 on the tool holder receptacle 12 is ensured. Furthermore, the adjustment part 32 engages laterally on a projecting shoulder 86 of the tool holder 10, this shoulder 86 having a height that is slightly greater than the overall height of the adjustment part 32 as seen in the direction of the alignment part 30.

An adjustment device 90 in the form of the eccentric bushing 60 is used for pre-positioning the previously described alignment part 30 in a predeterminable adjustment plane 88 for the tool holder receptacle 12. The adjustment device 90 is therefore a component of the alignment part 30, which is arranged stationary relative to the tool holder receptacle 12. The adjustment device 90 is characterized by an eccentricity e in the alignment part 30. The alignment part 30, designed in the manner of the eccentric bushing 60, has, as shown in particular in Figs. 4 and 5, two bushing parts 92, 94 arranged eccentrically offset from one another, of which one bushing part 92 is rotatably guided in the fitting bore 62 of the tool holder receptacle 12. The other bushing part 94, however, is enclosed by the adjusting part 32, in particular by the central bore 58 of the sliding block 42. The eccentricity e mentioned, which is in the order of less than 0.1 mm

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is achieved in that the two bushing parts 92,94 have circular-cylindrical outer peripheral surfaces which are arranged offset from one another at a step 96 by the mentioned eccentricity e, wherein the bushing parts 92,94 are otherwise arranged coaxially to one another with regard to their common central axis 98.

The eccentric bushing 60 is designed in the form of a hollow dowel pin and has an extended cone 100 at one of its free ends to facilitate driving into the dowel hole 62. The eccentric bushing 60 can be removed from the dowel hole 62 in the usual way using an internal thread 102 (Fig. 5) using a suitable tool (not shown). Otherwise, the fit clearances are selected such that the eccentric bushing 60 is guided with its one bushing part 92 in a rotatable manner in the dowel hole 62. For the corresponding rotary movement with regard to a setting process to be carried out, the eccentric bushing 60 has an engagement point 104 for an adjustment tool, for example in the form of an Allen key or the like (not shown). The rotary movement of the eccentric bushing 60 in the fitting bore 62 can thus be carried out by the tool engaging the engagement point 104, so that the eccentricity for the actual alignment device comes into effect.

In order to clarify the alignment device according to the invention, it will now be explained in more detail using a practical adjustment procedure.

In order to define a precisely specified adjustment plane 88 for the alignment processes with the alignment device, after the eccentric bushing 60 has been inserted into the fitting bore 62 as described, the eccentricity e of the eccentric bushing 60 is used to bring the center axis 98 in an adjustment plane 88 into alignment with the first drive axis 14 of the tool.

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tool holder 10 or with the corresponding longitudinal axis of the tool holder receptacle 12. The corresponding setting process using the eccentricity e is carried out with the aid of a setting gauge. This allows the center axis 98 of the eccentric bushing 60 to be aligned with the longitudinal axis of the tool holder receptacle 12. Via the engagement point 104 of the eccentric bushing 60, which has been omitted in Figs. 2 and 3 for the sake of simplicity of illustration, the eccentric bushing 60 is moved by a turning or swiveling process over its one bushing part 92 in the fitting bore 62 until the center axis 98 comes to lie in the setting plane 88. The eccentric bushing 60 is thus rotated from its position according to Fig.3 before pre-positioning for such a position into the position according to Fig.2, where the center axis 98 of the eccentric bushing 60 and the center axis of the tool holder receptacle 12 and thus later, when the tool is inserted, the first drive axis 14 of the tool holder 10 are in a common adjustment plane 88. Due to this pre-positioning, a precise alignment for the machining tool held in the tool holder 18 is provided and a lateral offset that impairs the machining accuracy is definitely excluded.

The corresponding basic setting or pre-positioning via the eccentric bushing 60 can preferably be carried out once by the tool manufacturer, but the corresponding positioning option is also available during later operation on site, provided the setting gauge is available. As soon as the corresponding pre- or basic setting is completed, the center hole 58 of the sliding block 42 is set to the diameter of the alignment pin in the form of the eccentric bushing 60 using the stop screw 66 for diameter adjustment. The receiving

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The measuring housing 40 is fixed to the tool holder 10, in particular to its projecting shoulder 86, via the fixing screw 78.

The tool holder 10 is then inserted into the receiving opening of the tool holder receptacle 12 and clamped over the clamping piece 24 with approximately 10 to 25% of the maximum clamping force. The tool holder 10 and thus the two drive axes 14, 16 are then adjusted in their angular position using the adjustment device 32. This allows the tool holder 10 to initially rotate about the first drive axis 14 and thus take the second drive axis 16 with it in a pivoting direction which, as viewed in the direction of Fig. 1, is perpendicular to the plane of the drawing. In Fig. 2, the deflection possibility of the second drive axis 16 in both directions about its central position defined by the adjusted adjustment plane 88 is indicated by arrows 106 facing one another. The deflection possibility occurs along the arrows 106 in a defined manner relative to the adjustment plane 88 and not in the direction of a plane offset from this adjustment plane 88.

The force of the spring assembly is preferably dimensioned such that it is in any case greater than the machining forces of the cutting tool of the tool holder 10 acting on the angle setting. Basically, the sliding block 42 therefore remains in its fixed position on the eccentric pin 60 and when the actuating screw 50 is actuated, the receiving housing 50 and thus the projecting shoulder 86 as well as the tool holder 10 move a predeterminable distance around the first drive axis 14. If the actuating screw 50 is tightened clockwise, the second drive axis 16 also pivots clockwise and vice versa, so that the operator finds a clear actuation for the angle setting.

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The alignment device according to the invention also makes sense when the eccentric bushing 60 acts on fixed moving parts. However, in the simplified constructions not shown in detail in this regard, the advantages resulting from the spring-loaded link part of the adjustment part 32 are not achieved.

Claims (8)

1. Alignment device for the relative position adjustment of a tool holder ( 10 ) with respect to a tool holder receptacle ( 12 ) in machine tools in the form of a pivoting movement with an alignment part ( 30 ) which cooperates with an adjustment part ( 32 ), characterized in that an adjustment device ( 90 ) is provided for pre-positioning the alignment part ( 30 ) in a predeterminable adjustment plane ( 88 ) with respect to the tool holder receptacle ( 18 ). 2. Alignment device according to claim 1, characterized in that the adjusting device ( 90 ) is a component of the alignment part ( 30 ) which is arranged stationary to the tool holder receptacle ( 12 ), and that the adjusting part ( 32 ) is connected to the tool holder ( 10 ). 3. Alignment device according to claim 2, characterized in that the adjusting device ( 90 ) is formed by an eccentricity (e) in the alignment part ( 30 ). 4. Alignment device according to claim 3, characterized in that the alignment part ( 30 ) is designed in the manner of an eccentric bushing ( 60 ) which has two bushing parts ( 92 , 94 ) arranged eccentrically offset from one another, of which one bushing part ( 92 ) is rotatably guided in the tool holder receptacle ( 12 ) and the other bushing part ( 94 ) is encompassed by the adjustment part ( 32 ). 5. Alignment device according to claim 4, characterized in that the adjusting part ( 32 ) is provided with a receiving housing ( 40 ) in which a guide part ( 36 ) is guided in a longitudinally displaceable manner, into which the other socket part ( 94 ) engages. 6. Alignment device according to claim 5, characterized in that the guide part ( 36 ) is guided in the receiving housing ( 40 ) so as to be longitudinally displaceable against the action of a force accumulator ( 34 ) and that the guide part ( 36 ) is designed in the manner of a sliding block ( 42 ) which has a central bore ( 58 ) as an engagement point for the other bushing part ( 94 ). 7. Alignment device according to claim 6, characterized in that the energy accumulator ( 34 ) is formed from at least one compression spring, in particular a disc spring, which acts on one side (44) of the sliding block ( 42 ) and that an actuating part, in particular in the form of an actuating screw ( 50 ), acts on its other side (48). 8. Alignment device according to one of claims 1 to 7, characterized in that the tool holder ( 10 ) is an angle spindle head which can be releasably secured to the tool holder receptacle ( 12 ) via a clamping piece ( 24 ).