MXPA99007784A - Oil film bearing sleeve and enchavet settlement - Google Patents

Abstract

The present invention relates to a roller mill oil film bearing of the type having a sleeve with a tapered inner surface received axially in and fixed rotatably with respect to a tapered section of a roller neck, the sleeve having a cylindrical external surface with journal for rotation inside a bushing contained in a block, with the plug, bushing and sleeve axially removable as a unit from the roll neck, the improvement comprising: said sleeve has a maximum external diameter equal to cylindrical outer surface diameter, and at least one key to the sleeve, the key has a base portion attached to an outer portion by an intermediate portion, the base portion protrudes radially inwardly from the inside of the sleeve and sits in a slot in the roller neck, the middle portion extends radially through the sleeve, the outer portion projects radially towards the It was from the outside of the sleeve and can be coupled through the bushing during the axial removal of the unit from the rodil neck

Description

OIL FILM BEARING SLEEVE AND BINDING ARRANGEMENT BACKGROUND OF THE I NVENTION FIELD OF THE INVENTION This invention relates generally to oil film bearings of the type used to rotationally support the tapered roller necks in a roller mill, and is related in particular to an improvement in the sleeves used in such bearings, as well as how to rotatably fix such sleeves and axially remove such sleeves from the roll collars.

DESCRIPTION OF THE PREVIOUS ICA TECHNIQUE In a conventional oil film bearing of the type shown in Figure 7, a sleeve 10 is received axially in the tapered section 12 of a roller neck projecting axially from the body. 16 of roller. The sleeve has a tapered inner surface 18 received axially in the tapered tapered neck section 12, and a cylindrical outer surface 20 with journal for rotation in a bushing 22 contained in and fixed relative to a plug 24. One end of the sleeve it is provided with a circular eyebrow 26 projecting outwards radially, as well as with a circular collar 28 projecting radially inwardly.

Key grooves 30 are machined in the collar 28. The keys 32 are received in the grooves 34 in a reduced diameter cylindrical extension 36 of the roller neck. The keys 32 protrude towards the key grooves 30 in the inner sleeve collar 28 to secure the sleeve 10 against rotation relative to the tapered neck section 12. Other conventional bearing components include an assembly 38 inward seal, nesting retention sleeve 40, thrust bearing 42 and associated sealing and external sealing elements generally represented at 44. The plug 24, bushing 22, sleeve 10 and the other conventional components described above are capable of being received axially in and removable from the roll neck as a single unit or assembly. During the axial removal, the plug 24 is pulled in the direction of the arrow 46. The bushing 22 follows the plug, and by virtue of the plug-in of the outer end of the hub with the eyebrow 26 of the sleeve, the sleeve is axially extracted and removed from the tapered section 12 of the roller neck. With reference to Figure 8, it will be understood that the sleeve 10 is machined from a forged piece 48 cylindrical produced with external and internal diameters indicated in "X" and "Y" respectively. Figure 9 shows the longitudinal section profile of the sleeve 10 imposed on a dotted line contour of the longitudinal section profile of the forged part 48. It will be seen that the external diameter X of the forged part is dictated by the need to accommodate the external circular eyebrow 26, and that the internal diameter Y is dictated in a similar manner by the need to accommodate the circular collar 28 of the inner sleeve.

During the machining of the forged part to produce the sleeve, metal is removed externally in "a" and "b", and internally in "c" and "d". The resulting loss of metal through machining gives an amount of approximately 2.6 times the weight of the finished sleeve. Thus, a forged piece of 4,300 kg is required to produce a sleeve weighing approximately 1,635 kg, with approximately 2,665 kg of metal lost during the machining process. The cost of this lost metal is substantial, as is the cost of heat treating it repeatedly during the forging and subsequently removing it during the machining process. The object of the present invention is to achieve significant reductions in these costs by reducing both the size of the forged piece required to produce the sleeve and the amount of metal loss during the machining of the subsequent forged piece.

BRIEF DESCRIPTION OF THE INVENTION The present invention derives from the understanding that significant reductions can be made in the size of the blank in forging as well as in the costs incurred in its processing and machining by removing the circular eyebrow 26 projecting towards out radially in favor of elements, separated which can be secured to the sleeve after machining in order to provide the required mechanical intercoupling between the sleeve and the bushing during the removal of the bearing. Preferably, the separate elements comprise radial keys that engage with the roll neck and the sleeve in a manner that also allows the elimination of the circular sleeve collar 28 protruding into the conventional inside. These and other objects, aspects and advantages of the present invention will now be described in greater detail with reference to the accompanying drawings, wherein: BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal sectional view of a bearing assembly incorporating a preferred embodiment of a sleeve and locking arrangement according to the present invention; Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1; Figure 3 is a longitudinal sectional view of the sleeve shown in Figure 1 superimposed on the contour of a forged blank having a thinner cylindrical wall and a reduced outer diameter; Figure 4 is a partial sectional view showing an alternate embodiment of a keying arrangement in accordance with the present invention; Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4; Figure 6 is a partial cross-sectional view through another embodiment of a sleeve according to the present invention; Figure 7 is a longitudinal sectional view of a roller mill oil film bearing incorporating a conventional sleeve and a keying arrangement; Figure 8 is a perspective view of. a conventional cylindrical forged cylindrical piece; and Figure 9 is a longitudinal sectional view of a conventional sleeve superimposed on the longitudinal sectional contour of a cylindrical forged cylindrical piece from which the sleeve is machined.

DETAILED DESCRIPTION OF I LUSTRATED MODALITIES An oil film bearing incorporating a preferred embodiment of a redesigned sleeve and keypad arrangement in accordance with the present invention is shown in Figures 1 and 2, where similar reference numerals have been employed. to identify conventional components described above with reference to Figure 7. The sleeve 50 of the present invention is again provided with a tapered inner surface 52 seated in a tapered section 12 of the roll neck, and an outer cylindrical surface 54 with journal stub. rotation in the bushing 22 contained within the plug 24. The key assemblies indicated generally at 56 are used to rotatably fix the sleeve 50 to the roll neck. Each key has a T-shaped configuration generally, with a radial segment 56a having an external portion 56b projecting engageable by the hub 2 during the axial removal of the roller neck bearing. The radial segment 56a extends through a stepped perforation in the sleeve 50 and is connected to a base segment 56c by means of bolt 58 or other similar fastener. The base segment 56c is received in a slot 60 cut in the cylindrical neck section 36 adjacent the tapered section 12 of the roll neck. The external portions 56b projecting radially from the keys 56 take the place of the conventional circular sleeve eyebrow 26, and the base segments 56c of the keys take the place of the conventional inwardly projecting circular collar 28. Thus, as shown in Figure 3, the maximum external diameter X of the forged piece 4/8 'can now be reduced to the diameter of the resulting cylindrical outer surface 54, and the minimum internal diameter Y of the forged piece can now be increased to the minimum internal diameter of the internal surface 52 tapered. With this configuration, the cylindrical blank 48 'can be forged with a thinner wall having external and internal diameters X, Y respectively that approximate the diameter of the cylindrical outer surface 54 and the minimum diameter of the inner surface 52 tapered . In addition, machining is required only minimally at b 'as well as internally at d' to provide the required internal taper. By employing a thinner, smaller forged coarse piece and reducing material loss through machining, the present invention realizes savings in weight of the order of 25% compared to the production of the conventional sleeve design shown in Figure 7.

An alternate embodiment of the invention is shown in Figures 4 and 5. Here, each key 62 is unitary and L-shaped generally, with a base portion 62a received again in a slot 60 in the roll neck section 36. cylindrical of reduced diameter. An intermediate key portion 62b is received in a slot 64 at the end of the sleeve 50, and an end portion 62c projecting radially outwardly is positioned for interengagement with the bushing 22 during the removal of the roller neck bearing. The key 62 is held in place in the slot 64 by a conventional threaded fastener 65. Here again, the sleeve 50 has a maximum external diameter equal to the diameter of its outer cylindrical surface 54, and a minimum internal diameter equal to the minimum diameter of its tapered inner surface 52. Yet another less preferred embodiment is illustrated in Figure 6 Here, the conventional circular inner collar 28 has been retained in order to accommodate retrofit to conventional rollers. However, the outer sleeve eyebrow has been replaced again by one or more elements 66 projecting radially received in cavities 68 and secured in place by fasteners 70. Although this arrangement offers less savings in lost metal and machining costs, it can still count for a decrease in lost metal in the order of 10% compared to what is experienced when the conventional sleeve shown in Figure 7 is produced. In light of the foregoing, it will now be apr ciated by those skilled in the art. that numerous modifications to the described modalities are possible. For example, the shape of the keys can be varied with the only limitation being the logrp of anti-rotational interengagement between the sleeve and the roll neck and axial interengagement between the sleeve and the outer bushing end. The number of keys can be varied, as can the manner in which they are removably secured in the bearing assembly. It is my intention to cover these and any other changes or modifications encompassed within the scope of the appended claims.

Claims (9)

1. REVIVAL NAMES 1. In a roll mill oil film bearing of the type having a sleeve with a tapered inner surface axially received in and rotatably fixed with respect to a tapered section of a roll neck, the sleeve having a cylindrical outer surface with stump for rotation within a bushing contained in a block, with the block, bushing and sleeve being axially removable as a unit of the roll neck, the improvement comprising: • said sleeve that is machined from a cylindrical forged cylindrical piece and having a maximum external diameter equal to the diameter of said cylindrical outer surface; and • at least one element separated from said coarse piece forged and secured to said sleeve, said element having an external portion projecting radially engageable by said hub during the axial removal of said unit from said roller neck.
2. 2. The improvement as claimed in claim 1 wherein said element comprises a key for rotatably fixing said sleeve with respect to the tapered section of said roller neck.
3. 3. The improvement as claimed in claim 2 wherein said sleeve has a minimum internal diameter equal to the minimum diameter of said tapered inner surface.
4. 4. The improvement as claimed in claim 2 or 3 wherein said key has a base portion attached to said outer portion by an intermediate portion, said base portion being seated in a groove in said roller neck and said intermediate portion. It is in mechanical intercoupling with said sleeve.
5. 5. The improvement as claimed in claim 4 wherein the intermediate portion of said key is received in a slot at one end of said sleeve.
6. 6. The improvement as claimed in claim 4 wherein the intermediate portion of said key protrudes through an opening in said sleeve.
7. The improvement as claimed in claim 4 wherein said roller neck is provided with a cylindrical section adjacent said tapered section, and wherein the base portion of said key is seated in a groove in said cylindrical section.
8. 8. The improvement as claimed in claim 4 wherein said base portion is detachably attached to said intermediate portion. A sleeve for use in an oil film bearing assembly of the type used to support the tapered neck of a roller mill roll for rotation within a bushing contained in a dowel, said sleeve comprising: • a tubular wall having a tapered inner surface dimensioned to be received in said tapered neck, and an outer cylindrical surface dimensioned to be received in said hub, the maximum external diameter of said wall being equal to the diameter of said outer cylindrical surface. Q. The sleeve as claimed in claim 9 wherein the minimum internal diameter of said wall is equal to the minimum diameter of said tapered inner surface.