GB2400430A

GB2400430A - Coupling hub with centring means comprising resilient wall portions

Info

Publication number: GB2400430A
Application number: GB0406780A
Authority: GB
Inventors: Nikolaus Martin Erlmann; Andreas Ruecker
Original assignee: Spicer Gelenkwellenbau & Co KG GmbH; Spicer Gelenkwellenbau GmbH
Current assignee: Spicer Gelenkwellenbau & Co KG GmbH; Spicer Gelenkwellenbau GmbH
Priority date: 2003-04-08
Filing date: 2004-03-26
Publication date: 2004-10-13
Anticipated expiration: 2024-03-26
Also published as: GB0406780D0; AT500285A3; GB2400430B; DE10316261A1; DE10316261B4; AT500285A2

Abstract

A coupling hub 10 has a receiving bore 31, an inner face 35 and at least two elastically deformable portions of wall 37, 38 arranged distributed around the circumference of the inner face 35, each of the deformable wall portions having a support face 41, 42 serving to radially support a stub shaft (11, figure 1). The resilient portions may be part of a centring ring 33, and the hub may also comprise pressure elements 49, 50 to transmit torque between the hub and the shaft stub. The resilient portions 37, 38 may be formed by bores 46, 47 and slots 44, 45 in the centring ring 33. Also disclosed are arrangement in which the resilient members are provided by spring elements (figures 17-23).

Description

Title: Coupling Hub for Coupling a Universal Joint Shaft to a Shaft Stub

Description of Invention

This invention relates to a coupling hub for coupling a universal joint shaft to a shaft stub. Coupling hubs of this type are, especially, used in shaft hub-connections between a universal joint shaft and a connection stub of a drive shaft of a roller in a rolling mill. In this case, the universal joint shaft has two universal joints, of which one is connected detachably to the roller, to enable a simple Remounting of the roller. For this, the universal joint shaft is connected to the above mentioned coupling hub, which can be pushed onto a shaft stub of the roller.

In connection therewith, the problem arises, that because of its own weight and because of clearance, which is necessary to be able to push the coupling hub onto the shaft stub, an out-of-balance can be produced. This problem arises especially when a large installation length exists, i. e. a large distance between the coupling hub and the universal joint connected to the coupling hub. This is for example the case in the drive arrangement disclosed in DE 19748450 C2. There are two rollers arranged one above the other, which, respectively, are driven by a universal joint shaft. As the radial distance between the rollers is very small, the universal joint shafts are formed such that the universal joints of both universal joint shafts, connected to the rollers, are arranged axially off-set from each other. Therefore, the universal joint of the one universal joint shaft is arranged closer to the coupling hub than the universal joint of the other universal joint shaft. As the distance between the coupling hub and the centre point of articulation of the universal joint of the second universal joint shaft is relatively large, an out-of-balance would have extremely negative effects here, because of the long cantilever arm.

To take up clearance between a coupling hub and a shaft stub, DE 4102848 C1 shows a clamping element, received in a radial bore of the coupling hub. The clamping element has an inner part and an outer part, which are connected to each other in a pressure sealed manner and between which a pressure chamber is formed. The pressure chamber is filled with hydraulic fluid, so that by means of pressurization the pressure chamber can be expanded.

Thus, the inner part is supported on a shaft stub, so that the shaft stub is clamped.

It is disadvantageous however, that in the arrangement of two clamping elements, which are arranged diametrically opposite to each other, no automatic centring of the shaft stub is possible. The longitudinal axis of the coupling hub can deviate, when clamping the shaft stub, from the longitudinal axis of the shaft stub. Furthermore, the clamping elements have, because of their hydraulic working principle, a cumbersome structure.

An object of the present invention is to provide a coupling hub, which has simple means for taking up play between the coupling hub and a shaft stub.

According to one aspect of the invention, we provide a coupling hub for coupling a universal joint shaft to a shaft stub, the hub having a longitudinal axis and comprsmg a receiving portion having an inner face extending around the longitudinal axis and serving for receiving the shaft stub, wherein the inner face forms part of a wall of the coupling hub, at least two elastically deformable portions of the wall arranged distributed around the circumference of the inner face, and for each elastically deformable portion a support face, serving for the radial support on the shaft stub.

The elastically deformable portions of the wall serve as spring elements, which, respectively, are supported with one support face on the shaft stub.

Therefore, on the one hand it is achieved, that the shaft stub is received in the receiving portion of the coupling hub without play, which receiving portion is provided in form of a receiving bore. Furthermore, by providing at least two elastically deformable portions, it is achieved, that the shaft stub is centred automatically relative to the coupling hub.

In the coupled condition, the distance between the support faces and the longitudinal axis may be smaller than the radius of the shaft stub in the area of abutment of the support face on the shaft stub. Thus, a defined pre-tensioning in the coupled condition can be achieved.

Preferably, the coupling hub comprises a coupling sleeve as well as a centring ring, wherein the centring ring is connected to the coupling sleeve and has the elastically deformable portions. Therefore, in the coupling sleeve torque transmitting faces can be provided, serving for the torque transmission between the coupling sleeve and the shaft stub, however, the centring ring only has the elastically deformable portions. Due to this, a separation of the functions for torque transmission and centring is ensured.

The elastically deformable portions may be in the form of spring arms, formed by slots, machined into the centring ring.

The slots may extend over the full length of the centring ring and may be machined into the centring ring starting from the inner face.

In the centring ring, through bores may be provided, which extend transversely to the longitudinal axis and are, respectively, aligned with threaded bores in the spring arms. Through the through bores screws can be inserted, which can be screwed into the threaded bores. Therefore, the spring arms can be radially deformed outwards by the screws, to facilitate the assembly of the shaft stub. Furthermore, the threaded bores are provided for the manufacture, as described in more detail when describing the drawings.

The spring arms may be formed such, that the slots extend over the complete radial thickness of the centring ring and form the contour of the spring arms.

In this case, in the spring arms, threaded bores can also be provided, extending transversely to the longitudinal axis, to enable a radial outward bending of the spring arms.

Furthermore, it can be provided, that the centring ring has a formed-on ring, which in axial direction is integrally connected at least on two portions to the centring ring, that the free ring segments of the ring, not connected to the centring ring, are elastically deformable and form the elastically deformable portions, and that the inner face of the ring has in the relaxed condition an oval cross-section, wherein the smallest diameter is smaller than the diameter of the shaft stub.

According to another aspect of the invention, we provide a coupling hub for coupling a universal joint shaft to a shaft stub, the hub having a longitudinal axis, and comprising a receiving portion having an inner face for receiving a shaft stub, wherein the inner face is part of a wall ofthe coupling hub, at least two spring elements, arranged distributedly around the circumference of the inner face, and for each spring element, a pressure element, radially displaceable guided in the wall and acted upon by spring means in the direction towards the longitudinal axis and forming a support face, serving for the support on the shaft stub.

In the not-coupled condition the distance between the support faces and the longitudinal axis may be smaller than the radius of the shaft stub in the area of the abutment of the support face on the shaft stub. Therefore, a defined pre tensioning is enabled.

The spring means can be represented by Belleville spring packs, which, respectively, are at least indirectly supported on the coupling hub and on one of the pressure elements.

To facilitate the pushing on of the coupling hub onto the shaft stub, it can be provided that the pressure elements can, respectively, rotate around a rotational axis, that the rotational axes intersect the longitudinal axis with a distance in-between and that the support face is formed rotational symmetrically around the rotational axis. Therefore, the pressure elements, when the coupling hub is pushed onto a shaft stub, are rotated around their rotational axis, so that no frictional forces are produced.

The spring means can be represented by elements made from an elastomer, which, respectively are supported on the coupling hub and on one of the pressure elements.

To ensure a centring at several axial positions of a shaft stub, it can be provided, that along the longitudinal axis, several spring elements are arranged one behind the other.

Preferred embodiments will now be described in detail by reference to the drawings, of which: Figure 1 shows two universal joint shafts having coupling hubs according to the invention; Figure 2 shows a longitudinal sectional view of a coupling hub of a first embodiment having a centring ring; Figure 3 shows a partial sectional view of the coupling hub of Figure 2; Figure 4 shows a front view of the centring ring of Figure 2; Figure 5 shows a partial longitudinal sectional view of the centring ring of Figure 4; Figure 6 shows a front view of the centring ring of Figure 4 in a clamping device; Figure 7 shows a partial longitudinal sectional view of the centring ring and the clamping device of Figure 6; Figure 8 shows a partial sectional view of a second embodiment of a centring ring; Figure 9 shows a side view of the centring ring of Figure 8; Figure 10 shows a partial longitudinal sectional view of the centring ring of Figure 9; Figure 11 shows a partial sectional view of a third embodiment of a centring ring; Figure 12 shows a side view of the centring ring of Figure 1 1; Figure 13 shows a partial sectional view of the centring ring of Figure 11; Figure 14 shows a partial sectional view of a fourth embodiment of a l O centering ring; Figure 15 shows a side view of the centring ring of Figure 14; Figure 16 shows a partial sectional view of the centring ring of Figure 14; Figure 17 shows a partial longitudinal sectional view of a further embodiment of a coupling hub; Figure 18 shows a sectional view of the coupling hub of Figure 17; Figure 18a shows a perspective view of a spring element formed alternatively to Figure 17; Figure 1 8b shows a perspective view of a further spring element formed alternatively to Figure 17; Figure 19 shows a longitudinal sectional view of a coupling hub having a centring ring of a further embodiment; Figure 20 shows a partial sectional view of the coupling hub of Figure 19; Figure 21 shows a side view of the centring ring of Figure 20; Figure 22 shows a partial sectional view of a further embodiment of a centring ring; and Figure 23 shows a side view of the centring ring of Figure 22.

Figure 1 shows a first universal joint shaft 1 and a second universal joint shaft 2 for driving rollers of a rolling mill. The first universal joint shaft 1 has a first universal joint 3 as well as a second universal joint 4, connected to each other by means of a connecting shaft 5. The first universal joint 3 comprises a first joint yoke 6 and a second joint yoke 7. The second joint yoke 7 is continuous with a connecting tube 8, on which end a flange 9 is provided. The flange 9 is connected to a coupling hub 10, which rests on a shaft stub 11 of a roller 12 and is nonrotationally connected thereto.

The second joint yoke 7 of the first universal joint 3 has a flange 13, connected to a flange 14 of the connecting shaft 5.

The second universal joint 4 has also a first joint yoke 15 and a second joint yoke 16, wherein the first joint yoke 15 is connected via a flange 17 to a flange 18 of the connecting shaft 5. The second joint yoke 16 has also a flange 19, serving for connecting the second universal joint 4 to a drive unit.

The connecting shaft 5 has a sliding unit 20. This is formed by a sliding sleeve 21 connected to the flange 18, by which the connecting shaft 5 is connected to the second universal joint 4. In the sliding sleeve 21 a sliding shaft stub 22 is guided so as to be axially displaceable. The sliding shaft stub 22 is connected to the flange 14 for connecting the connecting shaft 5 to the first universal joint 3. A spring 23 is arranged within the sliding unit 20 and is supported on the one hand on the sliding sleeve 21 and on the other hand on the sliding shaft stub 22 and acts, therefore, upon the sliding shaft stub 22, to take up the extended position. Therefore, it is ensured, that always a pressure force acts onto the first universal joint 3 and, therefore, onto the coupling hub 10, so that the coupling hub 10 is held fixed on the shaft stub 11.

The second universal joint shaft 2 is formed comparably to the first universal joint shaft 1, wherein this has also a first universal joint 24 and a second universal joint 25. The first universal joint 24 is arranged with a smaller distance to a coupling hub 26, which is connected to a shaft stub 27 of a further roller 28.

As the first universal joint 24 of the second universal joint shaft 2 is arranged closer to the coupling hub 26 than the first universal joint 3 of the first universal joint shaft 1 to the coupling hub 10, the two first universal joints 3, 24 are axially off-set to each other. By this, the universal joint shafts l, 2 can be arranged radially closer to each other, as the tube portions of the universal joint shafts 1, 2 have a smaller diameter than the first universal joints 3, 24. Due to this, however, at the first universal joint shaft 1, the problem may arise, that _because of the long protruding length, produced by the large distance of the first universal joint 3 to the coupling hub 10, an out-off balance is produced, when between the coupling hub 10 and the shaft stub 11 a radial play is present.

Because of the weight of the first universal joint shaft 1, the connecting tube 8 is bent downwards relative to a longitudinal axis 29 of the shaft stub 11, so that a displacement of the centre of gravity is produced.

To prevent this, play balancing elements are provided, as they are described in the following Figures.

Figures 2 and 3 show in two different views a coupling hub according to the invention, having a centring ring. Figure 4 shows a front view of the centring ring. Figures 2 to 4 are described in the following together.

The coupling hub 10 has a coupling sleeve 30, arranged around the longitudinal axis 29 and which has as a receiving portion a receiving bore 31 for the insertion of a shaft stub of a roller. The receiving bore 31 ends axially in a bore 32 having a reduced diameter compared to the receiving bore 31. In the bore 32 a centring ring 33 rests, which is connected to the coupling sleeve 30. The centring ring 33 serves for receiving a centring lug of the shaft stub.

The centring ring 33 serves further for centring the shaft stub by means of radial clamping of the centring lug of the shaft stub as described in the following. Distanced from the centring ring 33 a further ring 34 is connected to the coupling sleeve 30, serving also for the centring of the shaft stub, wherein the ring 34 does not abut the shaft stub with a pretensioning, but is manufactured with small tolerances, so that a small play is ensured between the shaft stub and the ring 34.

The centring ring 33 has an inner face 35 arranged around the longitudinal axis 29 and delimiting a wall 36 of the centring ring 33 as part of the coupling hub 10. In the wall 36 two elastically deformable portions 37, 38 are formed by radially elastically deformable spring arms 39, 40. In the area of the spring arms 39, 40, the inner face 35 represents support faces 41, 42. The support faces 41, 42 are supported in the mounted condition of the coupling hub 10 by means of pre- tensioning on an outer face of the centring lug of the shaft stub.

The spring arms 39, 40 are defined by slots 43, 44, 45. One slot 43 starts from the inner face 35 of the centring ring 33 and extends radially to the outside, until it is split into two further slots 44, 45 which extend roughly tangentially and in opposite direction to each other. The slots 44, 45 end, respectively, in bores 46, 47. The slots 43, 44, 45 as well as the bores 46, 47 extend over the complete axial length of the centring ring 33, so that the radially deformable springs arms 39, 40 are formed. The distances of the support faces 41, 42 to the longitudinal axis 29 are, respectively, smaller than the radius of the centring extension of the shaft stub in the area of the abutment of the support faces 41, 20. Furthermore, the distances of the support faces 41, 42 to the longitudinal axis 29 are smaller than the distance of the inner faces 35 of the residual portions to the longitudinal axis 29. By this, a defined abutment of only the support faces 41, 42 is ensured on the centring extension of the shaft stub, without that the residual portions ofthe inner face 35 come into abutment.

Over the circumference of the inner face 35 three further pairs of elastically deformable portions are distributedly arranged, which correspond to the above described pair of elastically deformable portions 37, 38. Therefore, respectively two pairs of elastically deformable portions are arranged diametrically opposite to each other, so that the shaft stub is clamped between these and is, therefore, automatically centred on the longitudinal axis 29. To be able to insert the shaft stub in an easier manner, the inner face 35 has in the direction towards the receiving bore 31 a chamfer 48, so that by means of inserting the shaft stub, the centring extension of the shaft stub slides axially along the chamfer 48 and due to this pushes the spring arms 39, 40 radially to the outside.

In the receiving bore 31, two pressure elements 49 are provided 1Q diametrically opposed, having, respectively, a pressure face 50 serving for the abutment on a corresponding face of the shaft stub. The receiving bore 31 has together with the pressure elements 49 a non-round cross-section for the transmission of torque. Therefore, the function of centring and the transmission of torque are structure-wise axially separated from each other.

For fixing the centring ring 33 in the bore 32, the centring ring 33 has a flange 51, in which attachment bores 52 are provided, which extend parallel to the longitudinal axis 29. The centring ring 33 can, therefore, be attached by means of screws engaging the coupling sleeve 30.

The Figures 5, 6 and 7 are described in the following for describing the production of the centring ring 33.

Figure 5 shows a longitudinal sectional view of the centring ring 33 along the section line B-B of Figure 4. For the respective spring arms 39, 40 through bores 53 are provided in the centring ring 33, wherein the through bores 53 start from an outer circumferential face 54 of the centring ring 33 and extend in the direction towards the respective spring arms 39, 40. The through bores 53 are, respectively, aligned with a threaded bore 55, which are provided in the respective spring arm 39.

For the production of the centring ring 33 it is initially started from a ring element, in which no spring arms are yet provided. The inner face 35 is produced in a first step in the form of a bore, which inner diameter corresponds to the diameter of the shaft stub minus a predetermined overdimension. In a second step the elastically deformable portions 37, 38, i.e. the spring arms 39, are, for example, achieved by cuts produced by wire electrical discharge machining. Furthermore, the through bores 53 and the threaded bores 55 are manufactured. In the following step the centring ring 33 is received in a clamping device 56. The clamping device 56 has a bore for receiving the centring ring 33. Furthermore, in the clamping device 56 bores are provided, which are aligned with the through bores 53 of the centring ring 33. Through the bores ofthe clamping device 56 and the through bores 53 tensioning screws 57 are passed and screwed into the threaded bores 55. The tensioning screws 57 are supported on an outer face 58 of the clamping device 56, so that, when screwing in the tensioning screws 57, the elastically deformable portions 37, 38 are expanded. The elastically deformable portions 37, 38 are expanded until the diameter in these areas is larger than the diameter of the shaft stub. Then the inner face 35 of the centring ring 33 is produced to the finished dimensions, wherein the not expanded portions have an inner diameter, which corresponds to the diameter of the shaft stub plus the predefined overdimension. After that, the tensioning screws 57 and the centring ring 33 are removed from the clamping device 56. The expanded elastical portions 37, 38 return, therefore, to their original position, in which the support faces 41, 42 have a distance to the longitudinal axis 29, which is slightly smaller than the radius of the shaft stub, and the inner face 35, in the residual areas, has a distance to the longitudinal axis 29, which is slightly larger than the radius of the shaft stub. Therefore, a defined abutment of the support faces 41,42 is ensured.

Figures 8, 9 and 10 show a second embodiment of a centring ring 133, wherein components, which correspond to components of the first embodiment, are provided with reference numerals which are increased by the numeric value 100.

The centring ring 133 has two elastically deformable portions 137, which are arranged diametrically opposite each other, wherein one of the elastic portions 137 is shown. The elastic portion 137 is formed by a spring arm 139, which is formed by slots 143, 144, 145 and bores 146, 146', 147, 147'. The slots 143, 144, 145 as well as the bores 146, 146', 147, 147' extend through the complete thickness of the centring ring 133. The slots 143, 144, 145 are arranged such, that they respectively meet each other at a right angle and, therefore, form the contour of the spring arm 139. In the spring arm 139, a radially extending threaded bore 155 is provided for expanding the spring arm - 10 139. The manufacture of the inner face 135 is achieved similar to the manufacture of the centring ring of the first embodiment.

Figures l l, 12 and 13 show a third embodiment of a centring ring 232 in different views. Components, corresponding to the components of the first embodiment, are provided with reference numerals, increased by the numeric value 200.

The second embodiment of the centring ring 232 has two pairs of elastic portions 237, 238, of which only one of the two pairs is shown. The elastic portions 237, 238 are represented by spring arms 239, 240. The spring arms are formed by slots 243, 244, 245, which extend through the thickness of the centring ring 233, i.e. the slots 243, 244, 245 start from the outer circumferential face 254 and end in the inner face 235. One of the slots 243 extends parallel to the longitudinal axis 229. On the ends of the slots this slot 243 is, respectively, intersected by a further slot 244, 245, extending in circumferential direction, so that the contours of the spring arms 239, 240 are formed. In the spring arms 239, 340, threaded bores 255, 255' are provided, so that the inner face 235 of the centring ring 233 can be manufactured similar to the inner face of the centring ring of the first embodiment.

Figures 14, 15 and 16 show a fourth embodiment of a cenking ring 333.

Components, corresponding to the components of the first embodiment, are provided with reference numerals, increased by the numeric value 300.

The centring ring 333 comprises a base ring 61 and a spring ring 62, arranged along the longitudinal axis 329 next to each other. The spring ring 62 is connected at two points to the base ring 61 in axial direction, so that free ring segments 63, 64 are formed, which are not connected to the base ring 61, but form slots 343, 344 together with the same. The inner face 335 of the spring ring 62 is formed oval in the not mounted condition of the cenking ring 333, wherein the smallest diameter is smaller than the diameter of the shaft stub.

The smallest diameter is arranged in the area of the free ring segments 63, 64, so that the free ring segments 63, 64 form support faces 341. If a shaft stub is inserted into the centring ring 333, the shaft stub slides initially on the chamfer 348 and deforms the free ring segments 63, 64 such, that the free ring segments 63, 64 in the area of the smallest diameter are deformed to the outside. In this case, it can be provided, that the inner face 335 of the spring ring 62 has a circular cross-section. Furthermore, for a better support it can be provided, that several free ring segments 63, 64 are formed.

Figures 17 and 18 show a further coupling hub according to the invention in two different views and are described in the following together.

The coupling hub 410 has a coupling sleeve 430, arranged around a longitudinal axis 429 and has a receiving bore 431 for receiving a shaft stub of a roller. In a wall 436 of the receiving bore 431, two spring elements 465, 466 are provided, which serve for centring the shaft stub by means of radial clamping, as described later. Furthermore, pressure plates 449, 449' are provided, which serve for the transmission of torque. On an end of the coupling sleeve 430, a ring 434 is provided, serving also for centring the shaft stub, wherein the ring 434 is manufactured with smaller tolerances, so that a small play between the shaft stub and the ring 434 is ensured and centres the shaft stub.

The receiving bore 431 has an inner face 345, arranged around the longitudinal axis 429 and which delimits the wall 436 of the centring ring 433 as part of the coupling hub 410. In the receiving bore 431, the two spring elements indicated generally at 465, 466 are arranged diametrically opposite one another. Both spring elements 465, 466 are identical. Therefore, only one of the two spring elements is described in the following. The spring element 465 has a plate-like pressure element 469, which is arranged in a recess 470 of to the receiving bore 431. The pressure element 469 forms a support face 441, serving for the abutment on the shaft stub and is, therefore, formed in a counter-fitting manner to the outer face of the shaft stub.

The spring element 465 has further spring means in form of Belleville spring packs 471, acting onto the pressure element in the direction towards the longitudinal axis with a force, to push the pressure element 469 in the mounted condition of the shaft stub against the outer face of the shaft stub. Thus, the Belleville spring pack 471 is supported on the coupling sleeve 430 as a part of the coupling hub 410 and on the pressure element 469. In total four units with Belleville spring packs 471 are provided, of which one is described in the following.

In the coupling sleeve 430 a through bore 472 is provided, which starts from an outer face 473 of the coupling sleeve 430 and ends in the recess 417.

Further, the through bore 472 is aligned with a threaded bore 474, provided in the pressure element 469. A tensioning screw 476 is passed through the through bore 472 and is screwed into the threaded bore 474. The other Belleville spring packs are formed identically.

Thus, by means of tightening the tensioning screw 476, the pressure element 469 is moved radially outwards, so that the shaft stub can be mounted.

In this case, the distance of the support face 441 of the pressure element 469 to the longitudinal axis 429 is larger than the radius of the shaft stub in the area of the abutment of the pressure element 469 on the shaft stub. After untightening the tensioning screw 476, the pressure element 469 is then urged by the Belleville spring pack 471 with a force against the shaft stub. In the not S mounted condition of the shaft stub, the distance of the pressure face 441 to the longitudinal axis 429 is smaller than the radius of the shaft stub in the area of the abutment of the pressure element 469 on the shaft stub, when the tensioning screw 476 is not tightened.

Each pressure element 469 is provided in total with four Belleville spring packs 471, wherein two Belleville spring packs 471 each are arranged in one cross-section and, respectively, two are arranged, when viewed in the longitudinal section one behind the other. Therefore, the pressure element 469 can be adjusted around an axis parallel to the longitudinal axis 429as well as around an axis, which intersects the longitudinal axis 429 with a distance in between.

For the transmission of a torque, two pressure plates 449, 449' are provided, which in relation to the spring elements 465, 466 are off-set by 90 about the longitudinal axis 429. The pressure plates 449, 449' are arranged diametrically opposite each other and are attached by means of attachment screw 467, 467', 468, 468' in the receiving bore 431. The pressure plates 449, 449' form pressure faces 450, 450', serving for the abutment on a corresponding face of the shaft stub. The cross-section of the receiving bore 451 forms together with the pressure plates 449, 449' a cross-section, deviating from a circle. By means of the pressure faces 450, 450' an introduced torque is transmitted to the shaft stub. Therefore, it is ensured, that the functions of transmitting a torque and of centring are structurally formed separately from each other.

Instead of the spring elements 465, 466, shown in Figures 17 and 18, a spring element 488 of Figure 18a can, respectively, be inserted into the recesses 470. The spring element 488 has two pressure elements 489, 490, connected elastically to a base element 491. The base element 491 is, respectively, received in one of the recesses 470, but the pressure elements 489, 490 are aligned in the direction towards the longitudinal axis 429. Therefore, when inserting the centring extension of the shaft stub into the centring ring 433, the pressure elements 489, 490 are radially pushed outwards, so that the centring extension is clamped. Figure 18b shows a spring element, which is similarly formed to that of Figure 18a, which, however, has an elastic flexibility in a direction off-set by 90 degrees.

Figure 19 shows a further embodiment of a coupling hub 510, which has a centring ring 533. Figures 20 and 21 show the centring ring 533 in different views. Figures 19, 20 and 21 are described together in the following, wherein components, which correspond to components of the embodiment of Figures 17 and 18, are provided with reference numerals, which are increased by the numeric value 100.

The coupling hub 510 has a coupling sleeve 530, arranged around the longitudinal axis 529 and has a receiving bore 531 for receiving a shaft stub of a roller. The receiving bore 531 merges axially in a bore 532, which has a reduced diameter compared to that of the receiving bore 531. In the bore 532, the centring ring 533 rests, which is connected to the coupling sleeve 530. The centring ring 533 serves for receiving a centring extension of the shaft stub.

The centring ring 533 centres the shaft stub by means of radial clamping the same, as described later. Distanced from the centring ring 533, a further ring 534 is connected to the coupling sleeve 530, serving also for the centring of the shaft stub, wherein the ring 534 is manufactured with smaller tolerances, so that a small play between the shaft stub and the ring 534 is ensured.

The centring ring 533 has an inner face 535, arranged around the longitudinal axis 529 and delimiting a wall 536 of the centring ring 533 as part of the coupling hub 510. In the wall 536, spring elements 565, 566 are provided, which are arranged diametrically opposite each other and by means of which the centring extension of the shaft stub can be clamped. The two spring elements 565, 566 are formed identically. Therefore, in the following only one of the two spring elements is described.

The wall 536 has a radially extending through bore 574, in which the spring element 565 rests. The spring element 565 comprises a pressure element 569, a lid element 577 as well as a Belleville spring pack 571. The Belleville spring pack 571 is supported on the pressure element 569 and the lid element 577 and therefore, is indirectly supported on the coupling sleeve 530 as part of the coupling hub 510. The through bore 572 starts from an outer circumferential face 573 of the centring ring 533 and ends in the inner face 335 of the centring ring 533. Starting from the outer face 573, the lid element 577 is inserted into the through bore 572, wherein the lid element 577 is supported on a first shoulder 579 of the through bore 572 in the direction towards the longitudinal axis 529. On a side of the lid element 577 facing away from the longitudinal axis 529, the lid element 577 is supported by a securing ring 580, wherein the securing ring 580 rests in a groove 581 of the through bore 572.

The pressure element 569 rests also in the through bore 572 and is supported radially in the direction towards the longitudinal axis 529 on a second shoulder 582 of the through bore 572. Between the pressure element 569 and the lid element 577, a receiving chamber 578 is formed, which houses the Belleville spring pack 571, so that the pressure element 569 is acted upon in the direction towards the longitudinal axis 529 by a force. In the not mounted condition of the shaft stub, in the coupling sleeve 533, the pressure element 569 is, therefore, urged against the second shoulder 582. It can be moved against the spring force of the Belleville spring pack 571 radially away from the longitudinal axis 529 in the direction towards the lid element 577, till the pressure element 569 is supported on the lid element 577.

The pressure element 569 is formed such, that in the not mounted condition of the shaft stub, the support face 541 is arranged with a smaller distance to the longitudinal axis 529 than the length radius of the shaft stub. By this, during the mounting of the shaft stub in the receiving bore 531 of the coupling sleeve 530 and by insertion of the centring extension of the shaft stub into the centring ring 533, the pressure element 569 is pushed against the spring force of the Belleville spring pack 571 radially outwards, so that the centring extension of the shaft stub is clamped.

As the two spring elements 565, 566 are arranged diametrically opposite to each other, it is ensured, that the centring extension is centred on the longitudinal axis 529.

For the assembly of the spring element 565, the lid element 577 has a central threaded bore 574, which is aligned with a through bore of the pressure element 569. Before the assembly, an attachment screw is passed through the through bore 583 and is screwed into the threaded bore 574, to, thus, pre tension the spring element 565. After the assembly of the spring element 565 in the through bore 572 and after securing the lid element 577 by the securing ring 85, the attachment screw is removed.

For fastening the centring ring 533 in the bore 532, the centring ring 533 has a flange 551, in which attachment bores 552, extending parallel to the longitudinal axis 529, are provided. The centring ring 533 can, therefore, be fixed by screws to the coupling sleeve 530.

Figures 22 and 23 show an alternative embodiment of a centring ring 633. Components, which correspond to components of the embodiment of Figures 19, 20 and 21, are provided with reference numerals, which are further increased by the numeric value 100.

The centring ring 633 has four spring elements 665, 666, which, respectively, are arranged diametrically in pairs to each other. All spring elements 665, 666 are formed identically, so that in the following only one of the spring elements is described.

The spring element 665 has a pressure element 669, which rests in a through bore 672 of the wall 636 of the centring ring. The through bore 672 extends from an outer face 654 of the centring ring 633 to an inner face 635.

The pressure element 669 is received in the through bore 672, so that it can rotate around the rotational axis 685. The pressure element 669 has a shaft portion 686, as well as a head portion 687, wherein the head portion 687 is arranged facing the longitudinal axis 629. In the shaft portion a groove 681 is provided, in which a securing ring 680 rests, wherein the securing ring 680 is supported in the direction towards the longitudinal axis 629 on a first shoulder 679 of the through bore 672. Therefore, the pressure element 669 is secured in the direction towards the longitudinal axis 629. The head portion 687 has a larger diameter than the shaft portion 686 and is arranged in an area of the through bore 672, which has an enlarged diameter. Between the head portion 687 and a second shoulder 682, a ring element 684, made from an elastomer, is arranged. The pressure element 669 is, therefore, supported in the direction away from the longitudinal axis 629 on the second shoulder 682. Facing away from the ring element 684, the head portion 687 forms a support face 641.

The pressure element 669 is arranged such, that the support face 641 only comes in an area between the rotational axis 685 and the circumference of the head portion 687 to rest on the centring extension of the shaft stub.

Furthermore, it is provided, that in the not mounted condition of the shaft stub in the coupling sleeve 630, the support face 641 projects inward beyond the inner face 635 of the centring ring 633. When inserting the shaft stub into the coupling sleeve 630 and, therefore, when inserting the centring extension of the shaft stub into the centring ring 633, the pressure element 669 is pushed against the spring force of the ring element 684 radially outwards, wherein because of the contact of the centring extension with the pressure element 669 in the area between the rotational axis 685 and the circumference of the head portion 687, the pressure element 669 is rotated around the rotational axis 685. Due to this, the forces for inserting the shaft stub in the coupling sleeve 630 can be reduced.

An exact adjustment of the loading of the pressure element 669 can be achieved by the adjustment of the thickness of the ring element 684 or by placing a washer underneath the same.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. Coupling hub for coupling a universal joint shaft to a shaft stub, the hub having a longitudinal axis and comprising a receiving portion having an inner face extending around the longitudinal axis and serving for receiving the shaft stub, wherein the inner face forms part of a wall of the coupling hub, at least two elastically deformable portions of the wall arranged distributed around the circumference of the inner face, and for each elastically deformable portion a support face, serving for the radial support on the shaft stub.

2. Coupling hub according to Claim 1, wherein in the not-coupled condition the distance between the support faces and the longitudinal axis is smaller than the radius of the shaft stub in the area of the abutment of the support face on the shaft stub.

3. Coupling hub according to Claim 1 or Claim 2, wherein the coupling hub comprises a coupling sleeve as well as a centring ring, wherein the centring ring is connected to the coupling sleeve and is provided with the elastically deformable portions.

4. Coupling hub according to any one of Claims 1 to 3, wherein the elastically deformable portions are in the form of spring arms.

5. Coupling hub according to Claim 4, wherein the spring arms are formed by slots, machined into the centring ring.

6. Coupling hub according to Claim 5, wherein the slots extend over the full length of the centring ring and are machined into the centring ring starting from the inner face.

7. Coupling hub according to Claim 6, wherein in the centring ring, through bores are provided, which extend transversely to the longitudinal axis and are aligned, respectively, with threaded bores in the spring arms.

8. Coupling hub according to Claim 5, wherein the slots extend across the complete radial thickness of the centring ring and form the contour of the spring arms.

9. Coupling hub according to Claim 8, wherein in the spring arms threaded bores are provided, extending transversely to the longitudinal axis.

10. Coupling hub according to Claim l or Claim 2, wherein the centring ring has a base ring and a spring ring, wherein the spring ring is integrally connected in axial direction at least on two portions to the base ring, the free ring segments of the spring ring, not connected to the base ring, are radially elastically deformable and form the elastically deformable portions, and the inner face of the spring ring has in the relaxed condition an oval cross-section, wherein the smallest diameter is smaller than the diameter of the shaft stub.

11. Coupling hub for coupling a universal joint shaft to a shaft stub, the hub having a longitudinal axis, and comprising a receiving portion having an inner face for receiving a shaft stub, wherein the inner face is part of a wall of the coupling hub, at least two spring elements, arranged distributedly around the circumference of the inner face, and for each spring element, a pressure element, radially displaceably guided in the wall and acted upon by spring means in the direction towards the longitudinal axis and forming a support face, serving for the support on the shaft stub.

12. Coupling hub according to Claim 11, wherein in the decoupled condition the distance between the support faces and the longitudinal axis is smaller than the radius of the shaft stub in the area of the abutment of the support face on the shaft stub.

13. Coupling hub according to Claim 11 or Claim 12, wherein the spring means are constituted by Belleville spring packs, which, respectively, are at least indirectly supported on the coupling hub and on one of the pressure elements.

14. Coupling hub according to any one of Claims 11 to 13, wherein the pressure elements each can rotate around a rotational axis, the rotational axes intersect the longitudinal axis with a distance in- between and the support face is formed rotationally symmetrically around the rotational axis.

15. Coupling hub according to any one of Claims 11 to 14, wherein the spring means are formed by elements made from an elastomer, which, respectively, are supported on the coupling hub and on one of the pressure elements.

16. Coupling hub according to any one of Claims 11 to 15, wherein along the longitudinal axis, several spring elements are arranged one behind the other. 1,

17. A coupling hub substantially as hereinbefore described with reference to andlor as shown in the accompanying drawings.

18. Any novel feature or novel combination of features described herein andlor in the accompanying drawings.