Title of Invention

CONE CLAMPING SET

Abstract

The cone clamping set serves, for example, to connect a shaft to a hub and is arranged in the radial space between the cylindrical outside circumferential surface of the shaft and the cylindrical inside circumferential surface of the hub. It comprises inner cone rings with a cylindrical inside circumferential surface and a conical outside circumferential surface as well as a thin-walled outer cone ring with conical inside circumferential surfaces resting against the outside circumferential surfaces of the inner cone ring and a cylindrical outside circumferential surface destined to rest against the inside circumferential surface of the hub. Axial clamping screws are distributed over the circumference, by means of which the cone rings can be pulled against one another axially. By a radial offset or circumferential groove the axial extent of the zone of the cylindrical outside circumferential surface of the outer cone ring, in which the radial clamping forces are transmitted onto the inside circumferential surface of the hub, is smaller than the axial extent of the zone in which the radial clamping forces act on the outside circumferential surface of the shaft, so that the contact pressure on the surfaces is increased. FIG 1.

Full Text

Cone clamping set The invention relates to a clamping set of the type indicated in the introductory part of claim 1. Such clamping sets are generally known as simple clamping sets and as double cone clamping sets, e.g. from the DE-GM 71 33 914, 77 27 308 and 75 12 290 as well as from the US-PS 3 958 888. The problem of the invention has occurred with clamping sets which correspond to Fig. 4 of the US-PS 3 958 888. The problem is with the double cone ring of the outer cone ring which with its cylindrical outer circumferential surface is supported in a hub bore. The conical inside circumferential surfaces are arranged in such a way that the greatest wall thickness of the double cone ring lies in the middle. In the middle a centring web is provided which extends up to the shaft and accordingly permits a centring of the hub relative to the shaft. The clamping screws extend axially through the two single cone rings. They pass through through-bores in the one cone ring and in the centring web and engage into threaded bores of the opposite cone ring. The single cone rings, because they accommodate the clamping screws, have radially in the area of the clamping forces in principle a greater wall thickness than the double cone ring, so that the latter easily deforms and eagerly rests against the inside circumference of the recess of the outer component. "Thin-walled" here and in the further context means that the radial wall thickness at every point of the zone in which the radial forces are transmitted, amounts to at the most half the radial wall thickness of the inside cone ring, but in general only to a third or a quarter of this wall thickness. When with a cone clamping set of this type for example a belt drive pulley for belt conveyors is fastened onto a shaft, because of the tension of the conveyor belt, the shaft is subjected to a considerable bending stress, which may cause a noticeable bending through of the shaft. This in turn results in that, on the side outside the bending area, the outside circumferential surface of the outer double cone ring may lift off slightly from the inside circumferential surface of the hub, also when initially during the tightening the cone clamping set was absolutely tight at the edge. This temporary lifting off of the outer double cone ring from the hub bore suffices to let moisture penetrate at this point, which leads there to the feared fretting corrosion which may make a subsequent dismantling of the cone clamping set impossible because the joint surfaces have rusted together. Willi the example of the belt drive pulley the water comes from the axially outer side which is exposed to the weather. The lifting off point revolves together with the turning of the shaft, so that a ring-shaped rust zone is formed. The penetrating of moisture and the subsequent formation of fretting corrosion occurs primarily on the outer side of the cone clamping set, i.e. in a zone located at the axial edge thereof on the radially outer circumferential surface resting in the hub, seeing that there the contact pressure is lower and the forces resulting from the bending will exceed the clamping forces first of all at this point. It is the object of the invention to avoid such an occurring of fretting corrosion. This object is achieved by the measure indicated in claim 1. Normally the axial zones in which the radial clamping forces are transmitted are about the same on the inside component, e.g. die shaft, and on the outside component, e.g. the hub. The result is that the contact pressure on the outside, because of the larger radius and the corresponding larger area available for the force transmission, is less than on the inside, i.e. on the shaft. The idea on which the invention is based is to reduce the axial zone available for transmitting the radial forces on the outside and in this way to artificially increase the contact pressure on the outside. As a result thereof also higher bending forces will no longer exceed the increased clamping forces under the normally occurring bending conditions and the contact of the clamping set in the outer edge zone is maintained, so that no moisture that causes fretting corrosion can penetrate. This means that higher bending forces can be withstood without the function being adversely affected. Experience shows that with the bending stresses that occur in practice, a residual contact or surface pressure of 80 N/mm2 on the outside of the bending area during the bending will still suffice to prevent the penetrating of water and accordingly prevents fretting corrosion. Because of the construction according to the invention, this residual contact pressure will occur only at greater bending moments. The artificial increase in the contact pressure in the recess of the outer component contributes to a better support in this recess and, moreover, reduces the stress on the clamping screws. The reduction of the outer zone can take place, for example, in such a way that the contact pressure in the recess of the outer component, for example the hub, is about the same as that on the inner component, for example the shaft (claim 2). The reduction of the force transmission zone and the associated increase in the contact pressure in the recess of the outer component can be realised in various ways. With the first embodiment according to claim 3 the cylindrical outside circumferential surface of the outer cone ring which forms the outer zone is axially shortened. With another possible embodiment (claim 4) the conical outside circumferential surface of the inner cone ring forming the outer zone is axially shortened relative to its cylindrical inside circumferential surface. According to claim 5 this shortened can also be obtained by a cone-shaped construction of the axial end faces of the inner cone ring. However, this embodiment requires machining work which in many cases would adversely affect the economy. The economical alternative can, therefore, generally be seen in that according to claim 6 the said outside circumferential surfaces are offset to a smaller diameter over an axial section. The contact and the transmission of the radial clamping forces then only take place in the areas that are not offset. Another possible embodiment (claim 7) provides that the conical inside circumferential surface of the outer cone ring at the thick-walled end changes over into a cylindrical surface, so that the desired shortening occurs. According to claim 8 the conical inside circumferential surface of the outer cone ring can also be offset to a larger diameter over an axial section. The effect of the invention is brought to the fore in a particularly consequent manner by the characteristic of claim 9. This, as a matter of fact, prevents that moisture can penetrate into the inside of the clamping set along the slot. With the preferred embodiment the clamping set comprises a double cone ring and two single cone rings co-operating with same (claim 10), wherein the double cone ring can, it is true, in principle be an inner or outer ring, but with the preferred embodiment is the outer cone ring (claim 11). With this preferred embodiment, according to claim 12 the reduction according to the invention of the transmission length of the radial clamping forces on the inside circumference of the outer component, e.g. the hub, can be formed by a continuous radial offset in the circumferential direction or by a flat circumferential groove. Exemplified embodiments of the invention are illustrated in the drawing. Fig. 1 and 6 show partial sections of the upper part of a clamping arrangement that pass through the axis of tins clamping arrangement. In Fig. 1 the double cone clamping set with the general reference numeral 100 serves to clamp an inner component formed by a shaft 1 with a cylindrical outer circumference 2 to a hub 3 forming an outer component with a recess with a cylindrical circumferential surface 4. The diameter of the inside circumference 4 is greater than the outside diameter of the shaft 1, and the clamping set 100 is accommodated in the resultant annular space 5. The clamping set 100 comprises a double cone ring 10 with a cylindrical outside circumferential surface 6 and two conical inside circumferential surfaces 7', 7" which are arranged in such a way that, seen axially, their greatest radial wall thickness lies in the middle. Co-operating with the conical surfaces 7', 7" are the outside conical surfaces 8', 8" of two single cone rings 11, 12, which with their cylindrical inside circumferential surfaces 9 rest in a contact area on the outside circumferential surface 2 of the shaft 1, which at the same time forms the zone 35 of the force transmission. Seen radially the cone rings 11,12 have a considerably greater wall thickness than the double cone ring 10 in the area of its conical surfaces T, 7". The ratio of the radial values is at every point of the conical surface T at least three to one. The double cone ring 10 comprises, so to speak, two joined thin-walled cone ring parts 18', 18". Between the conical surfaces 7f, 7" the double cone ring 10 has a radially inwardly projecting centring web 13, which with its cylindrical inside circumferential surface 14 rests on the outside circumferential surface 2 of the shaft 1 and serves to centre the hub 3 on the shaft 1. Distributed over the circumference, axial clamping screws 19 are provided close to one another, which pass through through-bores 15 in the cone ring 11 and 16 in the centring web and engage in threaded bores 17 in the cone ring 12. When tightening the clamping screws 19, the cone rings 11, 12 are pulled against one another and in doing so slide with their conical surfaces 8', 8" along the conical surfaces 1\ 7" of the double cone ring 10, which have the same cone angle and a corresponding radius, during which the cone ring pairs 18', 11 and 18", 12 respectively widen up radially and with the cylindrical surfaces 6 and 9 respectively come to rest against the cylindrical surfaces 4 and 2 respectively, under considerable contact pressure, so that the parts 1 and 3 are clamped together. The cone angle of the conical surfaces 7', 8' and 7", 8" respectively may lie outside or inside the self-locking range; in the latter case axial push-off screws must be provided if it must be possible to again remove the clamping set 100. Two critical points on the radially and axially outer edge of the double cone ring 10 are indicated in Fig. 1 by the reference numeral 20. When the shaft 1 bends through very badly, it may happen that the resultant forces become greater than the radial clamping forces and that the double cone ring in the outer areas of its cone ring parts 18, 18' lifts off from the inside circumferential surface 4. Moisture can then penetrate there, which may cause fretting corrosion which makes a dismantling of the cone ring 100 impossible or at any rate very difficult. The cone rings 11,12 and the cone ring parts 18', 18" normally rest against one another on axial sections 36. Especially when the clamping set 100 has been tightened very much or in the event of an unfavourable position of the tolerances, the section 36 comes close to the length of the cone rings 11, 12. The contact pressures on the cone surfaces 1\ 8* and 7", 8" and between the cylindrical outside circumferential surface 6 and the inside circumference 4 respectively will in that case, because of the larger radii, be considerably lower than between the inside circumferential surfaces 9 and the outside circumferential surface 2 of the shaft 1. To artificially increase the contact pressure on the outside and counteract the lifting off at the points 20, in the area of the sections 36 in the cylindrical outside circumferential surface of the double cone ring 10 offsets 22 are provided, between which the outside circumferential surface 6 is reduced to a smaller radius or diameter over a section 23. The depth of the offset or flat circumferential groove 24 need only be so great that in the section 23 no contact of the double cone ring 10 with the inside circumferential surface 4 takes place any more. A size of 1 mm suffices. It is essential that the offsets 22 lie in the section in which without the offsets 22 radial clamping forces would be transmitted. The parts of the circumferential surface 6 located in the section 23 would normally take part in the transmission of radial clamping forces, in particular in the areas that coincide axially with the cone rings 11, 12. When the clamping screws 19 are tightened evenly, these portions are now distributed onto zones 21, i.e. the remaining axially outer parts of the outside circumferential surface 6 in the area of the partial cone rings 18', 18", so that the radial contact near the critical points 20 becomes stronger and forces caused by a possible bending of the shaft 1 and directed towards a lifting off of the partial cone rings 18', 18" from the inside circumferential surface 4 can no longer exceed these contact forces or can no longer exceed them so easily. As a result thereof the clamping set 100 remains closed with respect to the inside circumferential surface 4 at the axially outer edges of the double cone ring 10, so that no moisture can penetrate. The zones 21 are axially shorter than the length 35 of the cone rings 11, 12, which correspond to the zone of the force transmission onto the shaft 1. For the same purpose the double cone ring 10 is not slotted, at least not in the area of its partial cone rings 18', 18", so that no moisture can penetrate through the slot. The centring web 13 and the two cone rings 11, 12 may on the other hand be slotted in order to avoid power losses. The double cone clamping set 100 illustrated in Fig. 1 is only an exemplified embodiment. It could also be a simple cone clamping set which is obtained, for example, when at the place marked by the dot-dash line 25 the double cone ring 10 is imagined cut off. The function of keeping the clamping set closed under bending stress at the right critical point 20 in the event of a strong bending through of the shaft 1, also exists in that case. Fig. 2 shows a double cone clamping set 200, with which parts with the same function have been given the same reference numerals. A double cone ring 30 is provided, which in this case is an inner cone ring and rests with its cylindrical inside circumferential surface 29 on the shaft 1. In this case the centring web 33 projects to the outside and lies with its cylindrical outside circumferential surface 34 against the cylindrical inside circumferential surface 4 of the outer component or the hub 3. The two cone rings 31, 32, into which the clamping screws 19 engage, are in this case provided with conical inside circumferential surfaces 39', 39" which co-operate with the conical outside circumferential surfaces 40', 40" of the double cone ring 30, as well as with conical outside circumferential surfaces 28', 28" which co-operate with the conical inside circumferential surfaces 27', 27" of two separate unslotted outer cone rings 38', 38", which with their cylindrical outside circumferential surfaces 26 rest against the inside circumference 4 of the hub 3. The outer cone rings 38' and 38" lie with their inner end faces against the centring web 33. In this case the critical points 20 are located at the radially and axially outer edge of the cone rings 38' and 38". Also here the cylindrical outside circumferential surfaces 26 are provided in the contact areas with offsets 22 at which the cylindrical outside circumferential surfaces 26 are reduced to a smaller diameter in relation to the thick-walled inner end of the cone rings 38', 38" over a section 43, so that no contact takes place there and the contact force or contact pressure in the remaining zones 21 of the transmission of radial forces increases so as to protect the critical points 20 against an opening up in the event of a bending stress of the shaft 1. Also here the axial length of the zone 21 is smaller than the axial length of the zone 35 in which the inner cone rings 31, 32 transmit the radial clamping forces inwards onto the shaft. In the exemplified embodiments described so far the axial shortening of the zones 21 in which the radial force transmission takes place, took place directly in the outside circumferential surface 6 and 26 respectively. However, because of the thin wall of the outer cone ring parts resting against the inside circumference 4 of the hub 3, the desired effect will also be obtained when the axial shortening of the force transmission zone takes place not on the outside circumference of the clamping set, but, seen radially from the outside, on the nearest adjoining conical surface. This is the case with the clamping set 300 of Fig. 3. The outside circumferential surface 46 of the double cone ring 50 is in this case continuously cylindrical. However, the conical outside circumferential surfaces 8', 8" have offsets 22, where they have been reduced to a smaller radius, so that there no contact with the conical inside circumferential surfaces 7', 7" of the double cone ring 50 takes place any more. In the exemplified embodiment the outside circumferential surfaces of the inner cone rings 51, 52, in the offset area of the outer circumference of the offset 56, extend parallel to the conical inside circumferential surfaces 7', T\ but basically any shaping can be used in this area. The force transmission ratios of the right inner cone ring 52 of the clamping set 300 are indicated by dot-dash lines. The conical surfaces 7" and 8" lie directly against one another in an axial area 44. It is understood, however, that the force transmission on the radially removed contact surfaces on the shaft 1 and hub 3 respectively are not limited to the area 44 delimited by planes extending perpendicularly to the axis. Because of the inherent stability of the cone rings, also the adjoining areas carry, as indicated by the dot-dash lines 54, 55 at the inner cone ring 52. The "zone 21'", in which the radial clamping force is transmitted onto the inside circumferential surface 4 containing the critical point 20, is not quite as short as the contact area 44, but slightly longer as indicated by the dot-dash line 53. The radial forces onto the outside circumferential surface 2 of the shaft are distributed likewise, as indicated by the dot-dash lines 54, 55. At any rate, however, the zone 21' is always still clearly shorter than the contact area 35 of the inner cone ring 52 on the shaft 1. With the clamping set 400 of Fig. 4 further possibilities are shown for shortening the axial zone of the direct contact with the conical surfaces 7', 8' and 7", 8" respectively. With the inner cone ring 62 the outside conical circumferential surface 8" remains conical over the entire contact area 35. This does not apply, however, to the conical inside circumferential surface 7" of the double cone ring 50, which from a point 58, which is located axially inside the contact area 35, changes over into a cylindrical surface 57, so that there is no more contact with the cone ring 62 on the outside at its left end. The same effect would be obtained by the cylindrical surface 59 indicated by broken line at the right end of the cone ring 62. Here the point 63 of the first contact with the conical surface 7" would, seen axially, be located at some distance from the right end of the double cone ring 50. The two cylindrical surfaces 57, 59 may also both be provided. Also in this case the axial zone 2V of the force transmission on the inside circumference 4 of the hub 3 is shorter than the contact area 35 on the shaft 1. The areas of the cone ring 62 located outside the dot-dash lines 54, 55 essentially do not take part in the transmission of the radial clamping forces. They could, therefore, also be removed without affecting the clamping effect, as is indicated in Fig. 4 by the cone-shaped construction of the right end wall 54' of the cone ring 61. However, generally the machining work would not justify such a cone-shaped construction. Also on the left side of the cone ring 61 in Fig. 4 a cone-shaped section 64 is provided, which reduces the area 44 of the actual contact with the conical surfaces 7', 8'. Also in this case the axial zone 21' of the force transmission on the inside circumferential surface 4 of the hub 3 is at any rate shorter than the contact area 35 on the shaft 1. With the clamping set 500 of Fig. 5, the two single outer cone rings 38', 38" have been combined into a double cone ring 60 which does not have a centring web but rests from the inside against the centring web 33 of an inner double cone ring 70. The outer double cone ring 60 is provided, the same as in Fig. 1, with offsets 22 which delimit a recess 24. The cone rings 31, 32 have, the same as in Fig. 2, conical outside and inside circumferential surfaces which co-operate with the corresponding counter-surfaces of the double cone rings 50, 70. The outside conical surfaces 28', 28" are provided in the middle with recesses 65, which take up one sixth to half the length of the force transmission surface on the conical surfaces 27', 28', 27", 28" and ensure that together with the recess 24 the shortened zone 21", indicated on the right side of Fig. 5, consisting of two parts, of the transmission of the radial clamping force is obtained, which is shorter than the corresponding zone 35 on the shaft 1. The clamping set 600 of Fig. 6 corresponds in its construction to the clamping set 200 of Fig. 2. However, the two outer cone rings 48, 48' have a continuous cylindrical outside circumferential surface 26. The shortening of the outer zone 21' of the radial clamping force transmission is obtained with the right cone ring by an offset 66 in the conical outside circumferential surface 28", which is located at the inner end thereof. With the exemplified embodiments offsets 22 are provided on outside circumferential surfaces. It is understood, however, that offsets 22 can also be provided in the respective inside circumferential surface of the outer cone ring, as indicated by a broken line on the outer cone ring 48' on the left side of Fig. 6, where an offset 66' is provided. Also here an axial shortening of the zone 21' of the force transmission on the inside circumference 4 of the hub 3 in relation to the zone 35 of the force transmission on the cylindrical outside circumferential surface 2 of the shaft 1 is realised by simple means. CLAIM 1. Conical clamping set (100, 200, 300, 400, 500, 600) for connecting an inner component with cylindrical outside circumferential surface (2), in particular a shaft (1), to an outer component with a recess with cylindrical inside circumferential surface (4), in particular a hub (3), which is destined to be arranged in the radial space (5) between the cylindrical outside circumferential surface (2) of the inner component and the cylindrical inside circumferential surface (4) of the recess of the outer component, with an inner cone ring (11, 12; 31, 32) with an inside circumferential surface and a conical outside circumferential surface (8', 8"; 28', 28"), with a thin-walled outer cone ring (10, 18', 18"; 38', 38"; 50; 60; 48', 48") with a conical inside circumferential surface (7', 7"; 27', 27") resting against the outside circumferential surface (8', 8"; 28', 28") of the inner cone ring (11, 12; 31, 32, 51, 52; 61, 62), having the same cone angle, and a cylindrical outside circumferential surface (6, 26, 46) destined to rest against the inside circumferential surface (4) of the outer component, and with axial clamping screws (19) distributed over the circumference, by means of which the cone rings (11, 12; 31, 32, 51, 52; 61, 62) can be pulled against one another axially with the conical surfaces (7', 8'; T\ 8"; 27', 28'; 27", 28") sliding over one another and widening up radially, producing radial clamping forces that act on the outside circumference of the inner component and on the inside circumference of the recess of the outer component, characterised in that the axial extent of the zone (21, 21') of the cylindrical outside circumferential surface (6, 26, 46) of the outer cone ring (10, 18', 18"; 38', 38"; 50; 60; 48\ 48"), in which the radial clamping forces are transmitted onto the inside circumferential surface (4) of the recess of the outer component, is smaller than the axial extent of the zone (35) in which the radial clamping forces act on the outside circumferential surface (2) of the inner component. Cone clamping set according to claim 1, characterised in that the axial extent of the zones (21, 21') and (35) are adapted to one another in such a way that the contact pressures on the inside circumference of the outer component and on the outside circumference of the inner component are essentially the same. Cone clamping set according to claim 1 or claim 2, characterised in that the cylindrical outside circumferential surface (6, 26) fonning the outer zone of the outer cone ring (10, 18', 18"; 38', 38", 60) is axially shortened. Cone clamping set according to claim 1 or 2, characterised in that the outside circumferential surface (8", 28") fonning the outer zone of the inner cone ring (52, 32) is axially shortened relative to its inside circumferential surface (39', 39"). Cone clamping set according to claim 4, characterised in that at least one axial end face (54', 64) of the inner cone ring (61) extends cone-shaped in such a way that the axial extent (44) of the inner cone ring (61) in the area of the outside circumferential surface (8') is smaller than in the area of the inside circumferential surface. Cone clamping set according to claim 4, characterised in that the outside circumferential surfaces (6, 26) are offset to a smaller diameter over an axial section (23,43). Cone clamping set according to claim 1 or 2, characterised in that the conical inside circumferential surface (7") of the outer cone ring (50) changes over into a cylindrical surface (57, 59) at the thick-walled or thin-walled end. Cone clamping set according to claim 1 or 2, characterised in that the conical inside circumferential surface (27') of the outer cone ring (48') in the area of the offset (66') is offset to a larger diameter over an axial section. Cone clamping set according to any one of the claims 1 to 8, characterised in that, seen radially, the outer cone rings (18', 18*"; 38', 38"; 48\ 48"; 50; 60) are relatively thin-walled and unslotted in the axial direction. Cone clamping set according to any one of the claims 1 to 9, characterised in that a double cone ring (10, 30, 50, 60, 70) and two single cone rings (11, 12; 31, 32, 51, 52; 61, 62) co-operating with same are provided. Cone clamping set according to claim 10, characterised in that the double cone ring (10, 50, 60) is the outer cone ring. Cone clamping set according to claim 11, characterised in that the double cone ring (10, 60) in its cylindrical outside circumferential surface (6, 26), approximately in the middle of its axial extent, is provided over an axial section (23) with an in the circumferential direction continuous radial offset (24). T* *P *r 13* Conical clamping set, substantially as herein described with reference to the accompanying drawings*

Documents:

927-mas-1997-abstract.pdf

927-mas-1997-claims duplicate.pdf

927-mas-1997-claims original.pdf

927-mas-1997-correspondence others.pdf

927-mas-1997-correspondence po.pdf

927-mas-1997-description complete duplicate.pdf

927-mas-1997-description complete original.pdf

927-mas-1997-form 1.pdf

927-mas-1997-form 26.pdf

927-mas-1997-form 3.pdf

927-mas-1997-form 4.pdf