WO2004009276A1

WO2004009276A1 - Connection between two machine parts

Info

Publication number: WO2004009276A1
Application number: PCT/EP2003/007466
Authority: WO
Inventors: Hans-Michael Weller
Original assignee: Hainbuch Gmbh Spannende Technik
Priority date: 2002-07-19
Filing date: 2003-07-10
Publication date: 2004-01-29
Also published as: AU2003246672A1; DE20320068U1; DE10234210A1; TW200413121A

Abstract

One embodiment of the invention relates to a machine tool spindle (11a) and a machine tool (20a) which are inserted into each other, axially and radially joined, and consequently connected by means of a conical member (17a, 21a). Mat-shaped bearings (14a), inside which balls (15a) are arranged, are disposed between the joining surfaces (13a, 22a). Said ball bearings (14a) allow the joining force to be very well conveyed in a radial direction while substantially reducing the friction at a great joining force.

Description

Description Connection of two machine parts

Field of application and state of the art

The invention relates to a connection between two machine parts, preferably a machine tool spindle and a machine tool or a device pallet or plate and a machine table, according to the preamble of claim 1.

Such connections between, for example, a machine tool spindle and a machine tool with cones are made in a known manner in that the cones are clamped into one another and thereby joined. The joining surfaces lie against one another or run against one another and press against one another, so that high friction occurs. At the same time, this abutting and pressing is required in many cases in order to create an exact joint and firm connection.

A further embodiment of the invention is provided for the general precise alignment and connection of two other parts which are used in mechanical engineering. For example, fixture pallets or plates have to be clamped on support surfaces such as machine tables in a precisely positioned position. Indexing pins are used for positioning. Most of these pins have a cylindrical shape. In some cases, linear ball guide bushes, as are known from cutting tools, are used for easier joining. The known indexing elements have the disadvantage that on the one hand they have to be set very precisely and on the other hand they are sometimes difficult to fit. This is especially true for large devices that have to be joined in parallel because of the cylindrical shape of the pins. Task and solution

The invention has for its object to provide a connection mentioned in the introduction, in which the friction can be reduced with a simultaneous exact connection.

This object is achieved by a connection with the features of claim 1. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. The wording of the claims is made the content of the description by express reference.

According to the invention, the two machine parts have an outer cone and an inner cone. Two or more cones can also be provided for each machine part. The two machine parts are aligned and fastened to each other with these cones. The connection takes place with an axial movement of two cones belonging to each other. At least one of the two cones is deformed in the area of the joining surfaces. According to the invention, bearings with rolling elements are provided here. These rolling elements have the advantage that, on the one hand, they are only subject to rolling friction and thus have a considerably lower frictional resistance. Furthermore, large forces or pressures can also be transmitted via rolling elements, so that deformation of the cone is still possible. Due to the reduced friction, the axial movement can either be carried out more easily or the joining force applied in the axial direction can be better converted into force for deforming the cone.

The bearings or rolling elements can be provided distributed in the circumferential direction between the inner cone and the outer cone. The rolling elements are advantageously continuous and have the same distance from one another. seen. This ensures good storage on the one hand and a reasonably uniform power transmission on the other.

In addition to a distribution of rolling elements in the circumferential direction, it can be provided that a plurality of rolling elements or a plurality of rows of rolling elements are provided in the axial direction. Two to four such rows of rolling elements are advantageously provided along the circumference. In principle, different or any rolling elements can be used. However, balls are advantageous. These have the advantage of simple manufacture and simple design of the bearing surfaces. The bearing surfaces are namely advantageously the surfaces of the cones. If balls are used, the cones can be produced in an exactly conical shape and relatively easily, for example, by turning.

In the simplest variant, the bearings consist of the surfaces of the cones and the rolling elements themselves. In a preferred embodiment of the invention, the bearings have a guide in which the rolling elements are guided and held. This is, for example, a so-called bullet rifle. Furthermore, it is possible to make the guide elastic. For example, it can be a rubber mat in which the rolling elements are mounted. They protrude slightly on both surfaces so that the rubber mat itself does not come into contact with the bearing surfaces or the conical surfaces. It is advantageous to lend a guide or rubber mat to be ring-shaped and / or closed. So it can run along the entire circumference of the joining surfaces without interruption.

The bearings, in particular with the aforementioned guide, are advantageously attached to one of the cones. This has the advantage that they do not have to be introduced, aligned or checked every time. They can be removed, for example for maintenance, repair or replacement. An exchange of a used bearing is possible. borrowed. A bearing is particularly advantageously attached to the machine tool spindle or the associated cone. Thus, only one bearing needs to be provided for a large number of machine tools to be inserted into a spindle. Furthermore, it is advantageous if the bearing is provided on the part of the machine tool that is essentially not freely portable.

The invention is provided in a further embodiment for the general precise alignment and connection of two other parts with the same features and characteristics of the joining by means of a tapered roller sleeve and elastic deformation in the area of the roller bodies. Here, a tapered pin is provided which carries the rolling element bush and has a cylindrical part at the rear end. The cylindrical extension is pressed into a corresponding hole in one of the two parts to be connected. As a second part of the precise alignment and connection, a cone ring is used in this version, which is also cylindrical on its outer surface. This is also pressed into a corresponding hole in the other part.

At least two such element pairs are required for precise positioning in all directions. After the parts have been joined, they are clamped axially or contracted. The bracing can be done in different known ways, for example screws.

In a further embodiment of the invention, the connection can have an axial stop or radial or approximately radially extending abutment surfaces. With these abutting surfaces, the two machine parts can be precisely connected to one another in the axial direction as a stop for the connection. It is thus possible to determine a precisely defined end point of the joining process and thus an exact position of the two machine parts in relation to one another. Such an abutment surface can be provided on a flange which projects outward from the outer cone. The flange advantageously protrudes substantially vertically, but smaller angular deviations are possible here and may be advantageous under certain circumstances. For this purpose, the other abutting surface is provided on an end face around the inner cone. The diameter of the abutting surfaces is relatively large, which in turn results in a corresponding accuracy in the position of the two machine parts relative to one another due to the radial distance.

Furthermore, it is possible to provide elevations in the area of a rolling element which run along one of the cones in the axial direction. This can be done, for example, in the manner of channels. The elevations have a rising surface in a direction along the circumferential direction. This area is advantageously increasing. The angle between the rising surface and the tangent to the conical surface in the area of the rolling element is greater than 0. Furthermore, it is smaller than a friction angle, which is determined by the material combination between the rolling element and the other cone. This has the advantage that the radial distance between the cones or joining surfaces decreases due to the elevation and thus the rolling element cannot roll when the two cones rotate relative to one another about the longitudinal axis. Because the friction angle is not exceeded, there is no friction between the rolling element and the conical surface, but a clamping. A type of anti-rotation device can thus be created which, in addition to the joining or connection of the two machine parts to one another, improves the transmission of a torque.

Such elevations are advantageously provided several times distributed in the circumferential direction. It can be particularly advantageously provided that a plurality of rolling elements, advantageously all rolling elements, at least one row, on an increasing surface of a previously mentioned exercise. In this way, all-round torque transmission can be achieved.

These and further features emerge from the claims and also from the description and the drawings, the individual features being realized individually or in groups in the form of sub-combinations in one embodiment of the invention and from other fields and being advantageous and protectable per se Can represent designs for which protection is claimed here. The division of the application into individual sections and sub-headings do not limit the general validity of the statements made under these.

Brief description of the drawings

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. The drawings show:

1 shows a section through a connection of a machine tool spindle to a machine tool and a rotating bearing according to the invention between the two parts, FIG. 2 shows a sectional view of a further connection according to the invention of a machine tool spindle to a machine tool,

Fig. 3 shows an enlarged detail of the arrangement of the bearing in the

2, FIG. 4 shows a plan view of a section in a radial plane through a connection similar to that from FIG. 1 with an outer bearing surface which has elevations,

5 shows an enlargement from FIG. 4, from which the configuration of the elevations emerges, Fig. 6 is an illustration of the further embodiment of the invention with two parts to be connected in the exploded state and

7 shows a cross section through FIG. 6 in the assembled state.

Detailed description of the exemplary embodiments

In Fig. 1, a simplified representation of a connection of a machine tool spindle 11a to a machine tool 20a is shown in section. In principle, these components correspond to the usual and known standard components. The spindle 11a has an inner groove 12 on its inside, which is designed to be tapered. The inside of the groove 12a forms the bearing or joining surface 13 of the spindle 11a. A bearing 14a is arranged in the groove 12a. The bearing 14a has balls 15a as bearings or rolling elements. The balls 15a are supported in a rubber mat 16a or are completely encased in them except for areas which protrude slightly on both sides. As already mentioned above, such bearings 14a are known per se from the prior art.

Furthermore, the spindle 11a has a type of flange 18a at the right end. The end face forms the abutting surface 19a.

Due to the fact that the groove 12a of the spindle 11a is formed both on the circumferential bearing surface 13a and on two lateral surfaces and thus also around the bearing 14a, this is inherently fixed in the spindle 11a. In the illustrated embodiment of the bearing 14a with the elastic rubber mat 16a, however, it can be removed by bending the rubber inwards, for example for replacement after wear. The machine tool 20a projects with the conical surface 21a or the corresponding cone into the spindle 11a. The cone 21a has on its outside the bearing or joining surface 22a, which is also conical.

Subsequently, the machine tool 20a has a flange 24a, which forms an abutment surface 25a. When the connection is closed, the abutting surface 25a lies against the abutting surface 19a of the spindle 11a. This serves as an axial stop for the connection of the two parts 11a and 20a.

A chuck 27a adjoins the flange 24a to the right. This is designed in a known manner, in the present case it corresponds to a shrink fit chuck. A tool shank 28a is located in the chuck 27a or a corresponding bore. The tool can be any, for example a drill or milling cutter.

Furthermore, both the spindle 11a and the machine tool 20a have an interior 31a which runs along the longitudinal axis shown in dashed lines. A clamping device is inserted into the interior 31a from the spindle 11a. This engages stop surfaces 32a in the interior 31a of the machine tool 20a and pulls the machine tool into the spindle. An axial bracing is thus achieved by this device. The abutting surfaces 19a and 25a form an axial stop for a precisely defined connection or position of the two parts 11a and 20a to one another. The bearings 14a between the bearing surfaces 13a and 22a specify the radial dimension between the two parts.

The exact function of the bearing 14a and the advantages achieved thereby are described further below. A further connection of a machine tool spindle 11b to a machine tool 20b is shown in section in FIG. 2. Unlike in FIG. 1, the spindle 11b here has a projecting cone 17b which is tapered to the right. The machine tool 20b, however, has an inner cone with conical surfaces 21b.

The cone 17b of the spindle 11b in turn has a groove 12b in which a rotating bearing 14b is inserted. This bearing 14b corresponds with the balls 15b in the rubber mat 16b in principle to that of FIG. 1.

The spindle 11b has a type of flange 18b with an abutment surface 19b. The machine tool 20b likewise has a type of flange 24b with an abutting surface 25b of the same type. Analogously to FIG. 1, the two parts 11b and 20b abut one another with the abutting surfaces 19b and 25b and are thus defined in relation to one another in the axial direction.

Instead of an internal train connection for securing the connection, as has been described above for FIG. 1, FIG. 2 provides for screwing the machine tool 20b onto the spindle 11b with screws 34. The screws 34b only secure in the axial direction. The fit is achieved in the axial direction by the abutting surfaces 19b and 25b and in the radial direction by the cones or bearing surfaces 13b and 22b.

FIG. 3 shows an enlargement of the bearing 14b shown at the top in FIG. 2 with the corresponding bearing surfaces 13b and 22b. From this it can be clearly seen that the balls 15b rest on both bearing or joining surfaces 13b and 22b. Thus, a power transmission can take place as a kind of clamping or compressive force, which acts on the inner cone, in this case cone 17b, and the outer cone, in this case cone 21b. This force causes a compression of the inner cone 17b or a corresponding widening of the outer one Cone 21b. It is assumed that the two have a certain elasticity or deformability in order to enable this compression or width.

This is again particularly well conceivable in FIG. 1, where the hollow configuration of the inner cone 21a, in this case the machine tool 20a, makes compression possible. In an analogous configuration, the inner cone 17b of the spindle 11b according to FIG. 2 has an interior space and can thus also be compressed. Since this expansion or compression takes place during the axial tensioning or movement of the two parts 11 and 20 against each other, the balls 15 of the bearing 14 will roll between the two bearing surfaces 13 and 22 according to their bearing function. At the same time, they can transmit a corresponding joining force, caused by the conical design of the bearing surfaces 13 and 22. After all, this is one of the advantageous properties of bearings with rolling elements.

Since the balls 15 roll between the two parts 11 and 20 during this movement, only rolling friction occurs. As has already been explained above, this is considerably less than surface friction if the bearing surfaces 13 and 22 lie directly against one another and slide past.

The provision of the balls 15 in the elastic rubber mat 16 of the bearing 14 has the advantage, on the one hand, that simple and inexpensive manufacture of such bearings is possible. On the other hand, such a bearing 14 can easily be produced as a closed and annular bearing. By stretching it can be brought into the groove 12b, for example, via the cone 17b. It sits there securely and captively. Alternatively, such a bearing 14 can simply be produced in the form of a strip, it not being connected at the ends to form a ring. It can be inserted as a strip in the groove 12. This is useful, for example in an embodiment according to FIG. 1. Due to a certain inherent rigidity, the bearing 14a automatically lays into the groove 12a and does not fall out inwards. As an alternative to such bearings with rubber mats 16, conventional bearings with metal cages for the balls 15 could also be provided.

In order to achieve an exact pressing of the two conical surfaces 17 and 21 against each other with a defined axial stop, the external conical surface and / or the internal conical surface will have a certain undersize or oversize. How high this undersize or oversize is to be selected depends on the individual circumstances, in particular the construction of the two parts 11 and 20.

Bearings 14 with three or four balls 15 are shown in the axial direction. Of course, these can also be more or less, with at least two balls being present. Furthermore, the spacing of the balls 15 can also be varied in the axial direction, advantageously there is a certain space between them. Of course, the wear is reduced and the transmission of the radial joining forces improves with an increase in the number of balls 15.

A further advantageous embodiment of the invention is shown in FIG. 4 and with a corresponding enlargement in FIG. 5. An anti-twist device is shown here in section along a radial plane by connecting a spindle 11c to a machine tool 20c or an outer cone 17c and an inner cone 21c.

Between the outer bearing surface 13c and the inner bearing surface 22c there is a circumferential bearing 14c with balls 15c which are embedded in a circumferential rubber mat 16c. This also serves as an example for the bearings 14a and 14b from FIGS. 1 to 3, how the balls 15 can be distributed in the circumferential direction. The bearing surface 22c of the inner cone 21c is exactly circular. In deviation from this, the bearing surface 13c of the outer cone 17c is provided with elevations 36c. The elevations 36c are designed in such a way that the bearing surface 13c deviates from a circular shape towards the inside and has the shape of a polygon. In particular, this means that an intermediate point 37c is selected exactly in the middle between two contact points of balls 15c on the bearing surface 13c, towards which the bearing surface runs as a straight line.

5 that the bearing surface 13c or its elevation 36c thus deviates inward from the circular surface at an angle α. This can be illustrated by the fact that the tangent shown in broken lines is applied to the contact point of the ball 15c with the outer cone 17c or the bearing surface 13c. The angle α lies between this tangent and the actual course of the bearing surface 13c with a straight section. Thus, the elevation 36c between the contact point and the intermediate point 37c increases with the angle α.

The elevations 36c or the angle α are designed such that α is larger than 0 on the one hand. On the other hand, α is smaller than a friction angle, which is predetermined by the material combination between ball 15c and outer cone 17c or bearing surface 13c. This angle of friction is determined by the combination of materials and in itself is independent of structural conditions. If the angle α is chosen to be greater than 0 and less than this friction angle, then the bearing surface 13c or the cone 17c cannot slide past the balls 15c or move with friction. So there is a blockage between the outer cone 17c and the bearing 14c.

As a result, a certain degree of security against rotation between the outer cone 17c and the inner cone 21c can be achieved. there If the bearing surface 13c or the elevations 36c are continued in the same shape or with the same angle α in the axial direction, a certain protection against rotation while maintaining axial mobility can be achieved. It can also be provided here that the intended angle α is only present when the two parts 11 and 20 axially stop each other and is even smaller before that, which facilitates axial joining.

If the two cones 17c and 21c should rotate against each other, the balls 15c would have to rub along the bearing surface 22c of the inner cone 21c. Since a very large force would be required for this, a type of anti-rotation device or a torque transmission is already achieved here. If the conical surface 21c is also chosen with elevations and an angle smaller than the friction angle of the material combination between balls 15c and bearing surface 22c, then an absolute blocking of a twisting movement takes place. In this way, good torque transmission can be achieved when working with the machine tool.

This can have the advantage that, in addition to an axial bracing device and the power transmission by the abutting surfaces 19 and 25 against one another, a torque transmission can be achieved via the bearing surfaces 13 and 22 in connection with the bearings 14.

In an embodiment according to FIG. 4, only one bearing surface is provided with elevations, and it makes sense to provide these on the cone of the spindle 11. Conventional, precisely conical, conical machine tools 20, which need not have elevations 26, can thus be clamped in the spindle 11.

FIG. 6 shows how any two machine parts, namely a counter plate 11d and a base plate 20d, are connected to one another. that can and are precisely aligned. The same basic principle as described above is used for this. The base plate 20d carries two protruding cones 17d with outer surfaces 21d. Balls 15d are attached to these, for example in a rubber mat or the like as described above. They can also be attached to the other bearing surface.

The cones 17d are introduced into corresponding bearing surfaces 13d, as is also shown in FIG. 7. The principle of alignment and bracing is the same as previously described.

Claims

claims

1. Connection of two machine parts, preferably a machine tool spindle (11) and a machine tool (20), the two machine parts being aligned with one another by means of at least one outer cone (17a, 21b) and a corresponding inner cone (17b, 21a) on joining surfaces (13, 22) and fastened, the two cones (17, 21) being joined in an axial movement with elastic deformation of one of the two cones in the area of the joining surfaces, characterized in that bearings (14) with rolling elements (15) are arranged between the joining surfaces.

2. Connection according to claim 1, characterized in that the bearings (14) or the rolling elements (15) are distributed in the circumferential direction, preferably substantially continuously or at equal intervals.

3. Connection according to claim 1 or 2, characterized in that the bearings (14) have a plurality of rolling elements (15) in the axial direction, preferably more than two.

4. Connection according to one of the preceding claims, characterized in that the rolling bodies are balls (15).

5. Connection according to one of the preceding claims, characterized in that the rolling bodies (15) are held in a guide (16) of the bearing (15), preferably in a ball bushing.

6. Connection according to claim 5, characterized in that the guide is elastic, in particular a rubber mat (16), in which the rolling elements (15) are mounted and protrude slightly.

7. Connection according to claim 5 or 6, characterized in that the guide is annular and closed along the entire circumference of the joining surfaces (13, 22).

8. Connection according to one of the preceding claims, characterized in that the bearings (14) are attached to one of the cones (17, 21), wherein they are in particular attached to the cone (17) of one part (11).

9. Connection according to one of the preceding claims, characterized in that at least two pairs of outer cone (17d, 21 d) and inner cone (13d) are provided on both parts to be connected (11d, 20d), which are preferably each on a common plane are provided.

10. Connection according to one of the preceding claims, characterized by radially extending abutment surfaces (19, 25) with which the two machine parts (11, 20) are connected as a stop of the connection in the axial direction.

11. Connection according to claim 10, characterized in that an abutment surface (19a, 25b) is provided on a flange (18a, 24b) which projects radially outwards from the outer cone (21b), and preferably the other abutment surface (19b, 25a) ) is provided on an end face around the inner cone (17a).

12. Connection according to one of the preceding claims, characterized by at least one elevation (36c) in the region of a rolling element (15c), the elevation running in the axial direction on one of the cones (17c) and the elevation in one Direction along the circumferential direction has a rising surface, the angle between the rising surface and the tangent to the conical surface in the area of the rolling element (15c) between 0 ° and a friction angle of the material combination between the rolling element (15c) and the other cone (21c) ,

13. Connection according to claim 12, characterized in that several elevations (36c) are provided distributed in the circumferential direction, preferably all rolling elements (15c) are provided in a row on a rising surface of an elevation.

Mf. Connection according to claim 12 or 13, characterized in that two elevations (36c) close to each other with the approach of the rising surface, so that a V-shaped recess is formed, the rolling elements (15c) running in the recesses.