EP1170091B1 - Chamfering tool - Google Patents

Description

The present invention relates to a countersink tool according to the preamble of claim 1.

Such countersink tools are known (see e.g. Prospectus Wendt GmbH).

From FR-A-2 013 231 is a combined drilling and milling tool according to the preamble of claim 1.

WO 98/57771 A describes a drilling tool for cutting a round hole, with a cylindrical tool neck of non-metallic Material. The drilling tool consists of a cylindrical tube, which front with a cutting surface or The like is provided.

With such countersink tools are drilled cylindrical Holes on glass panes coming from one side tapered then extended by a matched to the cone contour Attach attachment to these lowered holes. Such fastening systems are known inter alia under the names Multipoint®, Multiplex® ....

The conical countersunk zones of the holes serve this purpose also the centered recording of the fastening devices. These subsidence are therefore to be distinguished from subsidence, at most deburring cylindrical bores serve.

Therefore, such countersink tools have a proper Drive piece deep into the material of the glass pane Become the required depth reduction with the required To achieve strength properties.

Usually, such glass panes over several fastened such mounting holes, so that with increasing Number of fixing holes provided in the glass pane also the cost factor increases in case of glass breakage.

Even if today usually CNC machines for manufacturing This mounting holes used may not be overlooked that in the case of glass break all before or simultaneously carried out processing steps on the workpiece be nullified.

This danger is greater, the more such countersinking tools in processing mode to uncontrolled Oscillations tend.

Such uncontrolled vibrations can become uncontrolled Swinging or to a rattling movement of the Lead countersink tools on the workpiece. As usually the mounting holes introduced in the edge region of the glass material The risk of glass breakage is uncontrolled Oscillation behavior of the transmission chain between the tool spindle and abrasive coating quite considerable.

• relativ große auskragende Längen zwischen der Werkzeugspindel und dem Werkzeugkopf,
• große Hebellängen zwischen Spindelachse und Vorschubverfahrschlitten,
• zu geringe Antriebsleistungen der Werkzeugspindel,
• zu geringe Steifigkeit des Maschinengestells.

The possible causes of this vibration behavior are manifold. They should therefore be listed by way of example only:

• relatively large projecting lengths between the tool spindle and the tool head,
• large lever lengths between spindle axis and feed carriage,
• too low drive power of the tool spindle,
• too low rigidity of the machine frame.

The resulting relative movements between the Abrasive coating and the workpiece are virtually uncontrollable. This is partly due to the fact that the entire machine tool including workpiece and work spindle together with the countersink tool a system of predominantly elastic Materials is, which is determined by the permanent Excitation in operation certainly to considerable vibration amplitudes can sway.

Due to the widespread use of such machine tools it is also virtually impossible to take appropriate countermeasures to provide for the vibratory system of the machine tool, so that ultimately the object of the invention is, to improve the known countersink tools so that the tendency to vibrations or rattling and thus the tendency for glass breakage is significantly lower.

This object is achieved with the known countersink tool solved, by the characteristic features according to claim 1.

From the invention there is the advantage that under Retaining the previous machine tools, the tool holders and the whole periphery and while keeping usual Production speeds, the production yield increases.

This advantage is achieved by the inevitable Vibration movements by short-term elastic Deformations of the plastic intermediate piece and consumed in the Be damped plastic spacer. Therefore reduced the tendency for self-excited oscillatory movements, the inevitably by the continuously driven rotary motion of the countersink tool constantly arise again.

The plastic adapter serves practically as a coupling between the work spindle and the abrasive coating and consumes the occurring vibration excitations, so to speak within of its own volume, as it is compared to the other at the Oscillation movement involved machine and tool components is relatively flexible. Nevertheless, that will be Plastic spacer at best in the elastic range deform, since it consists of a pressure-resistant plastic, which always withstands the feed forces. As suitable Plastic can be considered Bakelite, for example. However, materials such as rubber, polyamide, PTFE (polytetrafluoroethylene) are and others conceivable.

It also does not occur for the present invention the compliance of the abrasive coating on the countersink tool, so that readily selected a plastic highest compressive strength can be.

This is especially true under the consideration that such Countersink tools in industrial manufacturing process Such glass panes should be used.

In this case, a basic principle of the invention is based on Considering that by the internal damping of the plastic the machine tool, in particular the spindle carrier and the tool spindle is significantly less bending under the present feed forces, since a part of the respective Feed of elastic deformation of the plastic intermediate piece recorded and consumed there.

This process takes place within the elastic Vibratory behavior of the tool spindle continuously from, so that also vibration movements from the machine tool even caught on the plastic adapter and there be consumed.

You do the inner damping properties of the plastic in the scope of elastic deformations of Utilize machine tool, tool holder and tool, as a result the invention a relative to the other materials in the transmission chain between machine tool and workpiece Pressure and bending soft zone via the plastic adapter is provided, in which any oscillatory movements in transformational work to be implemented, which ultimately to a possible heating of the plastic intermediate piece but considers the overall system as dissipation to be considered.

Thus occurs also in the border regions of the resonance frequencies a relatively strong internal damping on that within the entire oscillatory system remains. there is the expense of the invention, measured by progress, extremely low.

In principle, it is sufficient to have a plastic spacer in the drive chain between the drive shaft and the abrasive coating provide over which the full torque of the drive motor is transferred to the abrasive coating. The Plastic adapter should be used in industrial Range of channels interspersed to be communicating Flow connection between a usually axial Produce inflow channel and the abrasive coating. The invention avoids, among other things, a floating of the diamond coating, which comes about during processing, that small and smallest chips of glass removal add to the coating. These chips practically fill the spaces between the chips Diamonds off and stick to the surface of the tool, so that the diamond tips practically no longer in the production the reduction can be involved. This condition will Usually not detected by the machine tools, so that the feed drive despite reduced grinding ability of Abrasive lining continues to run.

The resulting high pressures can in conjunction with the elasticity not designed for this type of operation the machines trigger the feared vibrations.

The abrasive coating can be added between the spaces do not free the grinding diamond on its own, so that this operating condition is extremely unpleasant.

Here, the invention provides a remedy. The plastic adapter gives according to its pressure-elastic properties and thus enables the release of the removal.

In addition, the invention also takes into account the Course of the diamond sharpness over the life of the tool.

The slight yielding of the body remains the Initial sharpness of the diamond coating over a long period of time receive. The pressure-elastic system arises in principle on the requirements of the workpiece, so that the diamond coating will take an optimal sharpness.

It has been found that equipped with the invention Countersink tools until the end of service life no re-sharpening needed. Preferred embodiments result from the dependent claims.

Another advantage of the invention is the adaptability to different head angle of the countersink tool. This is understood to mean the cone angle with which the Tool head faces the workpiece and its apex lies on the geometric axis of rotation of the countersink tool.

This head angle can be in the range between 0 ° and 180 ° lie and thus an almost arbitrary value within this Take limits. In such countersinking tools separates However, a head angle of 0 ° as well as a head angle of 180 °.

Preferably, the head angle is in the range between about 30 ° to about 130 °, preferably at about 120 °, provided that subsidence manufacture for the above-mentioned fastening systems want.

In principle, a preferred embodiment differentiates the invention in two embodiments.

In the first embodiment, the plastic spacer forms the tool head and sits centered on the front End of the tool neck.

This embodiment provides the advantage that the tool head, which a relatively large distance to the tool spindle takes, consists of the lightweight plastic material and thus the countersink tool only to small vibration amplitudes stimulates.

For centering between plastic spacer and Tool neck can be a pair of central tab and associated central recess on the tool head or tool neck be provided. Advantageous embodiments are included in the subclaims.

The alternative embodiment provides that both Plastic adapter as well as tool neck in each case Plastic exist. Depending on the respective tool stresses can use different plastics become. Likewise, an integral and one-piece embodiment conceivable.

The invention can also be used on a combination tool, in which in front of the counterbore a drill section is provided for the preparation of the cylindrical bore in Workpiece. Immediately thereafter sets without tool change the Countersink part on the workpiece to the intended depth reduction manufacture.

In particular, when the plastic spacer the tool head forms, has glued to the plastic spacer Abrasive coating proven. It can easily do so to act around a bowl-shaped body that over one suitable pressure-resistant and heat-resistant adhesive high Shear strength connected to the tool head made of plastic is.

This bowl-shaped body can be made by a sintering process be prepared.

Fig.1

ein erstes Ausführungsbeispiel der Erfindung,

Fig.1a

Darstellung der Kopfwinkelgeometrie,

Fig.2

Aufsicht auf die Spitze eines Senkerwerkzeugs gemäß Fig.1,

Fig.3

ein Ausführungsbeispiel der Erfindung mit einem zweiteiligen Senkerwerkzeug aus Kunststoffmaterialien,

Fig.4

ein Ausführungsbeispiel der Erfindung mit einem einstückigen Senkerwerkzeug aus Kunststoff,

Fig.5

ein Ausführungsbeispiel der Erfindung mit vorgeordnetem Bohrabschnitt.

In the following the invention will be explained in more detail with reference to embodiments. Show it

Fig.1

a first embodiment of the invention,

1a

Representation of the head angle geometry,

Fig.2

Top view of the tip of a countersink tool according to Figure 1,

Figure 3

An embodiment of the invention with a two-part countersink tool made of plastic materials,

Figure 4

An embodiment of the invention with a one-piece countersink tool made of plastic,

Figure 5

an embodiment of the invention with upstream drill section.

Unless otherwise stated below, the following description always for all figures.

The figures show a countersinking tool 1 for the production of conical recesses 13 on cylindrical bores 12 in Glass panes 10.

For this purpose, a glass sheet 10 is located on a below of the countersink tool 1 located support 11 and is held there properly while the countersink tool 1 rotating about the (here) vertical axis of rotation the glass sheet 10 is lowered.

A portion of the bore 12 remains straight cylindrical, while the reduction 13 executed as so-called depth reduction becomes. These are to be understood as subsidence, their insertion depth in the glass sheet 10 is significantly larger than it alone necessary for a deburring of the cylindrical bore 12 would.

Such countersinking tool has a tool neck 6, the end in the tool holder of a drive spindle a machine tool 4 is clamped against rotation. On the Drive motor 3, the work spindle 2 is rotated. This rotational movement is optionally via a suitable Coupling end as a rotary motion in the tool neck 6 introduced there, where the drive end 5 is marked.

At the other end, the tool neck 6 has a tool head 7, which is equipped with a conical head angle 8 is.

There, the tool head 7 has a conical inclined surface, where the abrasive pad 9 is attached. through This abrasive pad 9 is at a corresponding feed of the Countersink tool 1 in the direction of the glass pane 10, the depth reduction 13 central and concentric with the straight cylindrical Bore 12 introduced from one side.

In addition, the coolant supply 26 is effected by a Axial channel, which the tool neck 6 to the tool head. 7 interspersed and there in a channel system 16a, b, c, d passes, which opens in the region of the abrasive pad 9 on the tool head.

In this case, the axial inflow passage 17 passes through the tool neck central to the axis of rotation, so that the coolant supply 26 is constantly communicating with the abrasive coating.

It is essential that the abrasive coating 9 via a Plastic spacer 14 against rotation with the drive spindle. 2 is connected and that the plastic spacer 14 with respect the force acting in the direction of the cone tip 15 feed forces pressure resistant and in addition good internal damping properties having.

The plastic spacer 14 follows in principle the head shape, which is defined by the apex 15 and has corresponding rotary drivers over which it rotatably connected to the drive spindle 2 is connected.

For this purpose serves - for example - a peripheral screw 27 in the embodiments according to. Fig.1, 3 and 5, by means of which the plastic intermediate piece 14 on the head side is posted on the tool neck 6. The circumferential screw connection 27 sits with a thread in a corresponding Tapped hole of the plastic spacer 14 and engages with a tapered pointed screw head corresponding recesses at the lower end of the tool neck 6 positively, so that the drive torque of the drive motor 3 directly into the plastic spacer 14th can be initiated.

In another embodiment, the rotary driver realized by a possible circumferential adhesive joint 28, between the plastic spacer 14 and the Pads of the tool neck is formed.

The plastic spacer 14 therefore forms a rotationally symmetrical solid component, which is abrasive coating side the conical head shape of the countersink tool and which Tool side of the associated rotationally symmetric Training the straight-cylindrical tool neck follows.

In this case, the material accumulation of the plastic intermediate piece 14 for the consumption of periodically recurring Forces and moments are used, which may be by the natural vibration behavior of the entire arrangement between Adjust machine tool 4 and workpiece 10.

For this purpose, the plastic spacer 14 with respect the force acting in the direction of the cone tip 15 feed forces pressure resistant and also has good internal damping properties on.

At least the plastic spacer 14 is such pressure resistant, that under the given feed forces during manufacture the depth reduction of the abrasive coating 9 substantially only subjected to compressive forces and therefore no elastic Deformations of the plastic spacer in the active area Must follow grinding zone.

This is achieved by a plastic, if necessary under pressure essentially unyielding is and also among those in the production of depth reduction occurring heating remains.

As suitable materials can in addition to rubber with accordingly high Shorehärtegraden also polyamide or polytetrafluoroethylene or comparable plastics use Find.

Especially these materials are for the benefit of the invention practically unyielding, but also relatively light and own In addition, damping properties at periodically occurring Forces and moments.

In addition, the figures show plastic spacers 14, which are interspersed by channels 10 and 16a to d. This is necessary if you want a communicating flow connection between the abrasive coating 9 and the axial inflow channel 26 create the active grinding zone always and continuously to supply with cooling liquid.

In the embodiments shown, the axial opens Inflow channel 14 additionally in a central distribution space 18, from which the radial channels 16a start up to 16d into the corresponding outlet openings in the Continue with abrasive coating 9.

In addition, FIG. 2 shows a segmentation of the abrasive coating 9 in (here) four equally sized ring segments, which from respective recess grooves 19 are interrupted. On the ground the recessed grooves 19 open the respective radial Channels 16a to d, so that the cooling liquid of the head shape following the plastic spacer 14 over the entire can distribute active grinding zone.

These recessed grooves 19 are in the direction of the countersinking tool 1 limited by the material of the plastic spacer and through the adjacent walls of each the conical head of the plastic spacer 14 applied and mutually adjacent ring segments of Abrasive coating 9.

In this case, the central terminal of the distribution channels 16a to 16d to the axial inflow passage 17 of importance. about the central distribution chamber 18 becomes a uniform supply achieved all distribution channels 16a to 16d, where it is in principle is sufficient, the distribution channels 16a to 16d to the central Distributor 18 to connect. An additional connection to the axial inflow channel 17, as shown, is not necessarily necessary.

Furthermore, the figures show countersink tools with head angles, which are smaller than 180 ° and larger than 0 °. In the shown Embodiments, the head angle is approximately 90 °.

In any case, however, the invention should be directed on head angle 8, which clearly has no face plates with a Angle of 180 ° and no straight-cylindrical discs are at an angle of 0 °.

In addition, FIG. 1 shows an exemplary embodiment which the plastic spacer 14 the tool head. 7 forms and centered on the front end of the tool neck. 6 is scheduled.

Here the centering consists of a pairing of central Projection 20 and associated central recess 21st on the tool head or tool neck. It is the Depth 23 of the projection 20 is less than the depth 24 of the recess 21, so that the central distribution chamber 18 also at completely deep set intermediate piece 14 is formed automatically.

The related distribution channels 16a to 16d can consequently mounted alone in the plastic spacer 14 be because the immersion depth 22 between projection 20 and recess 21 is less than the available depth 24 of the recess 21st

Consequently, the immersion depth 22 of the projection 20 is in the recess 21 is limited by a depth stop so that the central distribution space 18 is created, which on both sides of the abrasive pad 9 as well as on the side of the tool neck 6 communicates with a channel system for cooling fluid.

In the present case, the depth stop is by a Ring paragraph formed on the tool neck 6, against which the annular end face of the plastic intermediate piece 14 under Tightening of the compression fitting 27 held pressure-resistant.

For better distribution of the coolant in the area the active grinding zone may be provided, the channel system 16a to 16d on the side of the abrasive coating 9 in at least two to lead to different radii. This requirement is made possible by the basically conical tool head. All distribution channels 16a to 16d should be in the range the recessed grooves 19 on the top surface of the plastic spacer 14 lead.

In addition to this, FIGS. 3 and 4 show a development, in which both the plastic spacer 14 as also the tool neck 6 made of plastic.

In the case of the embodiment gem. Fig.3 consists of Tool neck 6 made of a plastic other than the plastic adapter 14. The attachment between plastic spacer 14 and tool neck 6 corresponds to the construction according to Fig.1.

In the embodiment of Figure 4, the entire countersink tool one-piece and one-piece made of plastic and can therefore be referred to as plastic spacer 14 become.

In addition to this, FIG. 5 shows an exemplary embodiment, in which the tool neck 6, the entire plastic spacer 14 in the direction of the apex 15 interspersed and this towered over a piece. There, the tool neck 6 forms a straight ring cylinder, which at the end face an abrasive Covering z. B. is sintered. Do you do that? Tool towards a glass plate 10, so will first once the straight cylindrical hole drilled, which subsequently from the subordinate countersink tool with the countersink is provided.

In all embodiments, the coating on the Glued on plastic spacer. To this end Two-component or hot-melt adhesives could be used.

Since the plastic spacer under the occurring here Stress is practically relentless, can easily Sintered linings are used, which are characterized by high Distinguish stability.

Claims (15)

1. Chamfering tool (1) for producing conical chamfers (13) on cylindrical bores (12) in panes of glass (10), said tool having a tool neck (6) to be clamped at its end into the tool holding fixture of a machine tool (4) and which has located at its other end a tool head (7) with a conical head angle (8), to the sloping surface of which the abrasive coating (9) is applied, characterised in that the abrasive coating (9) is connected via a plastics intermediate piece (14) to the drive spindle (2) so as to rotate with same, and in that the plastics intermediate piece (14) is pressure-resistant with respect to the feed forces acting in the direction towards the cone point (15) and additionally has good inner damping properties, in that the plastics intermediate piece (14) is provided with ducts (17, 16a to d), which create a communicating flow connection between the abrasive coating (9) and an axial feeder duct (26), which is supplied with cooling fluid, in that the radial depressions are grooves (19) which pass through the abrasive coating (9) in the direction towards the plastics intermediate piece (14), and in that the distribution ducts (16a to d) end in radial depressions in the abrasive coating (9), the plastics intermediate piece (14) basically following the head shape which is fixed by the cone point (15) and has appropriate rotation catches via which it is connected to the drive spindle (2) so as to rotate with same.
2. Chamfering tool according to claim 1, characterised in that the ducts (16a to d, 17) communicate with a central distribution chamber (18) and continue radially from there as far as the abrasive coating (9).
3. Chamfering tool according to claim 1 or 2, characterised in that the head angle (8) is smaller than 180° and larger than 0°.
4. Chamfering tool according to claim 3, characterised in that the head angle is greater than 110° and smaller than 130°.
5. Chamfering tool according to one of claims 1 to 4, characterised in that the plastics intermediate piece (14) forms the tool head (7) and is placed centred at the front end of the tool neck (6).
6. Chamfering tool according to claim 5, characterised in that the centring comprises a pairing of a central projection (20) and an associated central recess (21) on the tool head (7) or tool neck (6).
7. Chamfering tool according to claim 6, characterised in that the insertion depth (22) of the projection (20) in the recess (21) is so delimited by a bit stop that a central distribution chamber (18) is produced which communicates both on the side of the abrasive coating (9) and on the side of the tool neck (6) with a respective duct system (17; 16a to d) for cooling fluid.
8. Chamfering tool according to claim 7, characterised in that the duct system (16a to d) on the side of the abrasive coating (9) opens out in at least two different radii onto the machining location.
9. Chamfering tool according to one of claims 1 to 4, characterised in that the plastics intermediate piece (14) and also the tool neck (6) consist of plastics material.
10. Chamfering tool according to claim 9, characterised in that the plastics intermediate piece (14) and the tool neck (6) are configured in two parts and in that the two components are attached to each other.
11. Chamfering tool according to one of claims 1 to 10, characterised in that an adhesive joint (28) is formed between the connection surfaces of the plastics intermediate piece (14) and the adjacent tool parts.
12. Chamfering tool according to claim 9, characterised in that the plastics intermediate piece (14) and tool neck (6) are configured undivided and of one piece.
13. Chamfering tool according to one of claims 1 to 12, characterised in that a drill (25) is arranged in front of the plastics intermediate piece (14) and serves to produce the cylindrical bore.
14. Chamfering tool according to one of claims 1 to 13, characterised in that the abrasive coating is glued onto the plastics intermediate piece (14).
15. Chamfering tool according to claim 14, characterised in that the abrasive coating is sintered.

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