GB1583711A

GB1583711A - Roll device

Info

Publication number: GB1583711A
Application number: GB10988/78A
Authority: GB
Original assignee: Sandvik AB
Current assignee: Sandvik AB
Priority date: 1977-03-21
Filing date: 1978-03-20
Publication date: 1981-01-28
Also published as: JPS6059043B2; USRE31554E; IT7821429A0; JPS53123362A; SE7703169L; DE2811085C2; SE414277B; IT1093909B; DE2811085A1; BE865111A

Description

(54) ROLL DEVICE (71) We, SANDVIK AKTIEBOLAG of Fack, S-811 01, Sandviken 1, Sweden, a Joint Stock Company organised in accordance with the laws of Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an arrangement in a roll assembly.

When mounting a roll ring on a roll shaft different arrangements have been used for transmitting the torsional moment from shaft to ring. Such arrangements have not however proved entirely satisfactory.

In one such arrangement a conical centering sleeve is forced in between a roll ring and a roll shaft and the torsional moment is transmitted to the roll ring through this sleeve. The advantage of this arrangement is that roll ring and roll shaft can be manufactured with large tolerances and that the roll ring can easily be exchanged. A troublesome drawback, however, is that, when the conical sleeve is forced in between roll ring and roll shaft, such great tensile stresses are introduced into the roll ring, which in most cases is made of cemented carbide, that it sometimes fractures.

In another arrangement the roll ring is forced onto the shaft so tightly that relative movement between ring and shaft is eliminated. A grip that is great enough for transmission of moment is difficult and expensive to achieve, owing to the fact that close tolerances on roll ring and roll shaft are required. Other drawbacks are that it is difficult to mount the roll ring onto and to dismount it from the shaft, and that there is a risk that the brittle roll ring breaks when forcing it onto the shaft.

In a third arrangement the roll ring is prevented from rotation relatively to the roll shaft by axial clamping, the axial force being kept within fixed limits by applying a spring element in the connection to the roll ring.

The drawbacks of this joint is that it requires close tolerances on roll ring and roll shaft which makes the production of roll ring and roll shaft expensive and which makes it difficult to mount the roll ring onto and to dismount it from the shaft.

The present invention provides a roll device comprising at least one roll ring mounted on a roll shaft through a centering element between the roll ring and the roll shaft, the roll ring being clamped by axial pressure from a nut threaded on the shaft, the clamping force being applied to the roll ring through a first resilient element whilst the centering element is also subjected to axial pressure by the nut through a second resilient element, the clamping force so applied to the roll ring being substantially greater than the axial pressure on the centering element.

The centering element may suitably be composed of two wedge-type centering sleeves bearing against each other; an alternative arrangement is that it may be formed by a conical sleeve, either the roll ring or more preferably the roll shaft having a similar conical taper. The two resilient elements may be respectively a belleville washer which enables a comparatively large axial force to be applied to the roll ring, and a cup spring which applies a smaller axial force to the centering element.

The invention enables the construction of a roll device in which the production costs of the roll ring and roll shaft will be low, relatively speaking, and which allows a quick exchange of roll rings, because the roll ring being replaced is easy to dismount, the new one easy to mount.

In the accompanying drawings, Figure I shows one embodiment of the invention; and Figure 2 shows another embodiment of the invention.

Referring now to Figure 1 there are shown two roll rings 1, 2 (three or more roll rings can of course be mounted on-the roll shaft) mounted on a roll shaft 3, the clearances between rings and shaft being so great that both mounting and dismounting of the roll rings can be made quickly and simply by hand. Owing to these large clearances the roll rings must be provided with centering elements which are shown as two wedge-type centering sleeves 4, 5 bearing against each other and which are mounted between roll ring 1 and roll shaft, similar sleeves 6, 7 being provided for roll ring 2. Thanks to the fact that wedge-type centering sleeves are used, the roll shaft or the inner surface of the roll ring does not have to be conical but can be cylindrical.

Bearing against the centering sleeve 5 there is placed a resilient element 8 having a small spring force and a similar resilient element 9 bears against the sleeve 7. Radially outside the element 8 and bearing against the roll ring 1 there is positioned a distance ring 10.

Another distance ring 11 is positioned between the two roll rings 1 and 2 and has one part bearing against the upper part of the resilient element 9. Another resilient element 12 having very great spring force is positioned adjacent the resilient element 8 and the distance ring 10. The resilient element 12 has an upper part bearing against the distance ring 10 and another part bearing against an upper part of the resilient element 8. At the other side of the resilient element 12 and bearing against the same there is positioned an annular thrust element 13 which partially surrounds a mechanical lock nut 14 acting on the thrust element 13. In order to effect the axial thrust force on the roll joint a suitable hydraulic press element is applied against the thrust element. When the mechanical lock 14 has been tightened to full contact with the thrust element 13, the axial force from the press element can be released, whereafter the roll device is ready for use. It ought to be said that the distance between the lower parts of the two resilient elements 8 and 12 is so great that in spite of the full tightening of the lock nut 14 the parts do not touch each other.

In Figure 2 there is shown another embodiment of the roll device. A roll ring 22 is mounted on a roll shaft 21 and a centering element in the form of a conical sleeve 23 is mounted between ring and shaft. In this case that part of the shaft that is in contact with the sleeve 23 is tapered in order to provide a good contact surface for the conical sleeve 23. Outside the sleeve 23 and bearing against the roll ring 22 there is placed a resilient element. for instance a belleville washer 24, having very great spring force. Bearing against the centering sleeve 23 there is placed another resilient element, for instance a cup spring 25, having a small spring force. The resilient element 25 has not the same radial extension as the resilient element 24 and is positioned axially beside it. Against the two resilient elements bears an annular thrust element 26, which wholly or partially surrounds a mechanical lock nut 27. In order to effect the axial thrust force required a hydraulic nut 28 or a similar device is used against the thrust element 26. When a mechanical lock nut 27 has been tightened in a suitable way to full contact with the thrust element 26, the outer axial force can be released, whereafter the roll device is ready for use.

When dismounting the roll ring an axial force is applied against the thrust element 26, whereby the locking nut can be released and threaded off. After the thrust element 26 and the resilient elements 24 and 25 are taken off. Now the centering sleeve 23 and the roll ring 22 can be removed in a suitable way for instance by pumping pressure oil into a gap between shaft 21 and centering sleeve 23.

With both embodiments the centering sleeve or sleeves can be forced in between the shaft and the ring with a fixed force, which is small in relation to the axial clamping force on the roll ring, this force being transmitted from the thrust element by the second resilient element at the same time as the axial clamping force from the thrust element is applied on the roll ring by the first resilient element, the spring force of which is many times greater than that of the second element. The first resilient element could be positioned at the side of the roll ring remote from the locking nut but (not shown) is preferably interposed between the nut and the roll ring. By choosing resilient elements with different spring force the clamping forces on the centering sleeve and the roll ring can be regulated.

Thus, the assembly is done in one operation, and axial clamping of the roll ring for transmission of the torsional moment is obtained at the same time as the roll ring is centered and gets support at its inner diameter by the centering sleeve without undesirable and injurious tensile stresses being introduced into the roll ring.

WHAT WE CLAIM IS: 1. A roll device comprising at least one roll ring mounted on a roll shaft through a centering element between the roll ring and the roll shaft, the roll ring being clamped by axial pressure from a nut threaded on the shaft, the clamping force being applied to the roll ring through a first resilient element whilst the centering element is also subjected to axial pressure by the nut through a second resilient element, the clamping force

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the invention. Referring now to Figure 1 there are shown two roll rings 1, 2 (three or more roll rings can of course be mounted on-the roll shaft) mounted on a roll shaft 3, the clearances between rings and shaft being so great that both mounting and dismounting of the roll rings can be made quickly and simply by hand. Owing to these large clearances the roll rings must be provided with centering elements which are shown as two wedge-type centering sleeves 4, 5 bearing against each other and which are mounted between roll ring 1 and roll shaft, similar sleeves 6, 7 being provided for roll ring 2. Thanks to the fact that wedge-type centering sleeves are used, the roll shaft or the inner surface of the roll ring does not have to be conical but can be cylindrical. Bearing against the centering sleeve 5 there is placed a resilient element 8 having a small spring force and a similar resilient element 9 bears against the sleeve 7. Radially outside the element 8 and bearing against the roll ring 1 there is positioned a distance ring 10. Another distance ring 11 is positioned between the two roll rings 1 and 2 and has one part bearing against the upper part of the resilient element 9. Another resilient element 12 having very great spring force is positioned adjacent the resilient element 8 and the distance ring 10. The resilient element 12 has an upper part bearing against the distance ring 10 and another part bearing against an upper part of the resilient element 8. At the other side of the resilient element 12 and bearing against the same there is positioned an annular thrust element 13 which partially surrounds a mechanical lock nut 14 acting on the thrust element 13. In order to effect the axial thrust force on the roll joint a suitable hydraulic press element is applied against the thrust element. When the mechanical lock 14 has been tightened to full contact with the thrust element 13, the axial force from the press element can be released, whereafter the roll device is ready for use. It ought to be said that the distance between the lower parts of the two resilient elements 8 and 12 is so great that in spite of the full tightening of the lock nut 14 the parts do not touch each other. In Figure 2 there is shown another embodiment of the roll device. A roll ring 22 is mounted on a roll shaft 21 and a centering element in the form of a conical sleeve 23 is mounted between ring and shaft. In this case that part of the shaft that is in contact with the sleeve 23 is tapered in order to provide a good contact surface for the conical sleeve 23. Outside the sleeve 23 and bearing against the roll ring 22 there is placed a resilient element. for instance a belleville washer 24, having very great spring force. Bearing against the centering sleeve 23 there is placed another resilient element, for instance a cup spring 25, having a small spring force. The resilient element 25 has not the same radial extension as the resilient element 24 and is positioned axially beside it. Against the two resilient elements bears an annular thrust element 26, which wholly or partially surrounds a mechanical lock nut 27. In order to effect the axial thrust force required a hydraulic nut 28 or a similar device is used against the thrust element 26. When a mechanical lock nut 27 has been tightened in a suitable way to full contact with the thrust element 26, the outer axial force can be released, whereafter the roll device is ready for use. When dismounting the roll ring an axial force is applied against the thrust element 26, whereby the locking nut can be released and threaded off. After the thrust element 26 and the resilient elements 24 and 25 are taken off. Now the centering sleeve 23 and the roll ring 22 can be removed in a suitable way for instance by pumping pressure oil into a gap between shaft 21 and centering sleeve 23. With both embodiments the centering sleeve or sleeves can be forced in between the shaft and the ring with a fixed force, which is small in relation to the axial clamping force on the roll ring, this force being transmitted from the thrust element by the second resilient element at the same time as the axial clamping force from the thrust element is applied on the roll ring by the first resilient element, the spring force of which is many times greater than that of the second element. The first resilient element could be positioned at the side of the roll ring remote from the locking nut but (not shown) is preferably interposed between the nut and the roll ring. By choosing resilient elements with different spring force the clamping forces on the centering sleeve and the roll ring can be regulated. Thus, the assembly is done in one operation, and axial clamping of the roll ring for transmission of the torsional moment is obtained at the same time as the roll ring is centered and gets support at its inner diameter by the centering sleeve without undesirable and injurious tensile stresses being introduced into the roll ring. WHAT WE CLAIM IS:

1. A roll device comprising at least one roll ring mounted on a roll shaft through a centering element between the roll ring and the roll shaft, the roll ring being clamped by axial pressure from a nut threaded on the shaft, the clamping force being applied to the roll ring through a first resilient element whilst the centering element is also subjected to axial pressure by the nut through a second resilient element, the clamping force

so applied to the roll ring being substantially greater than the axial pressure on the centering element.

2. Device according to claim 1 wherein the first resilient element is interposed between the nut and the roll ring.

3. Device according to claim 1 or claim 2, wherein the centering element is composed of two wedge-type centering sleeves bearing against each other.

4. Device according to claim 1 or claim 2, wherein the centering element is composed of a conical sleeve.

5. Device according to any one of the preceding claims wherein the second resilient element is located between the first resilient element and the centering element.

6. Device according to any one of the preceding claims wherein the first resilient element is composed of a belleville washer.

7. Device according to any one of the preceding claims wherein the second resilient element is composed of a cup spring.

8. Device according to any one of the preceding claims wherein the lock nut acts on the resilient elements through a thrust element located round the roll shaft.

9. Device according to claim 8, wherein the thrust element has one part acting on the first resilient element and another part acting on the second resilient element.

10. Roll device substantially as shown in either of the figures of the accompanying drawings and described herein with reference thereto.