FR2749357A1 - Assembly of orientation roller bearing for axial and radial loads - Google Patents

Abstract

The assembly of an orientation roller bearing consisting of two frames (1,2), one fixed and the other mobile, and rollers, is made up of a interior ring (5) with a fixing piece (6) onto the upper face of the first frame (2), an external ring (3) with item for fixing it onto the second frame (1). A range of rolling elements (7) are fitted between the two rings (3,5) forming a rolling stop to transmit to the fixed chassis (1) the downward axial loads applied to the mobile frame (2). Another range of rollers (10) is placed between the two rings (3,5) to form a radial bearing transmitting to the fixed frame (1) the radial loads applied to the mobile frame (2). It is characterised by the fact that the external ring (3) has below it a series of rollers (7) forming a rolling stop, a lower part (3d) having an interior diameter less than the exterior diameter of the first frame (2) and containing a lower support surface (15) situated at a close axial distance above one of the upper support of the first frame.

Description

 Orientation bearing arrangement.

 The present invention relates to an orientation bearing arrangement comprising two frames, one fixed and the other movable, as well as an orientation bearing transmitting to the fixed frame on the one hand a load applied from top to bottom at the mobile chassis, axially or with offset from the axis by a maximum distance equal to 50% of the diameter of the bearing, and on the other hand also a radial load.

 Up to now, in order to avoid the mobile chassis from lifting and damaging the bearing or the surrounding systems in the event of an accidental axial load from bottom to top or too much accidental offset of the axial load directed from top to at the bottom, a bearing is used between the two chassis comprising three rows of rolling elements, namely a first row of rolling elements forming a rolling bearing transmit to the fixed chassis the axial loads applied from top to bottom to the movable chassis, a second row of rolling elements forming a rolling stop transmitting to the fixed chassis axial loads applied from the bottom to the top to the movable chassis, and a third row of rolling elements forming a radial bearing transmitting to the fixed chassis the radial loads applied to the chassis mobile.

 This complicates the structure of the bearing and increases the cost of the latter.

 The present invention relates to an orientation bearing arrangement which, while being of a simple structure and of a reduced cost, makes it possible to support, without risk of lifting the movable chassis and without risk of damage to the bearing and the systems. surrounding, not only the loads for which the arrangement is normally intended, namely a load applied from top to bottom on the movable chassis axially or with offset from the axis by a maximum distance equal to 50% of the diameter of the bearing , and a radial load, but also accidental loads, namely axial loads from bottom to top or axial loads from top to bottom with excessive eccentricity.

 The invention also relates to an orientation bearing arrangement in which the bearing comprises an outer ring axially subdivided into several removable partial rings to allow access to the internal parts of the bearing, the arrangement being designed so that even in the event of partial disassembly of the bearing for the purpose of inspecting and possibly repairing the main row of rolling elements, namely the row of rolling elements supporting the axial loads applied from top to bottom on the mobile chassis, therefore after disassembly of the row of rolling elements transmitting the radial loads, the bearing remains operational, that is to say can support both axial and radial loads.

 The orientation bearing arrangement which is the subject of the invention comprises two frames, one fixed and the other mobile, and an orientation bearing. The orientation bearing comprises an inner ring and means for fixing it to the upper face of a first of the chassis. The orientation bearing further comprises an outer ring and means for fixing it to the second chassis. The slewing bearing further comprises a row of rolling elements arranged between the two rings to form a rolling stop transmitting to the fixed chassis the axial loads applied from top to bottom to the movable chassis, and a row of rolling elements arranged between the two rings to form a radial bearing transmitting to the fixed chassis the radial loads applied to the mobile chassis. The outer ring has, below the row of rolling elements forming the rolling stop, a part having an inside diameter less than the outside diameter of the first chassis and having a lower bearing surface located axially at a small distance above d 'an upper bearing surface of the first chassis.

 Thanks to this arrangement, in the event of an accidental axial load from the bottom up or too much accidental eccentricity of the axial load directed from the bottom up, the mobile chassis can only be lifted by a value corresponding to the very small distance between the two bearing surfaces of the outer ring and of the first chassis, said accidental load then being transmitted by said bearing surfaces in contact with each other, without risk of damage to the bearing or the surrounding systems. In other words, this arrangement makes it possible to use an orientation bearing comprising not three, but only two rows of rolling elements, namely a row of rolling elements forming a stop, transmitting the radial loads in one direction, and a row of rolling elements forming a radial bearing transmitting the axial loads, while the accidental axial loads in the opposite direction are transmitted directly, which considerably simplifies the structure and the cost of the orientation bearing.

 It should be specified that the first chassis can be, depending on the case, mobile or fixed and the second fixed or mobile chassis, but that it is always on the first chassis that the inner ring of the slewing bearing is fixed and to the second chassis that is fixed the outer ring.

 In the case where the outer ring is divided axially into several removable partial rings to allow access to the internal parts of the bearing, the lower partial ring may have an inner diameter less than the outside diameter of the first chassis and have an inner bearing surface located radially a short distance outside of an outer bearing surface of the inner ring.

 Thus, after partial disassembly of the outer ring and the upper row of rolling elements forming the radial bearing, for the purpose of inspecting or repairing the rolling bearing, the radial load can be transmitted by said surfaces. support directly from the inner ring to the outer ring, so that the bearing remains "operational", that is to say continues to support both axial and radial loads.

 Preferably, at least one of the facing bearing surfaces is formed by one or more sliding pads attached either to the outer ring or to the inner ring.

 These sliding pads can for example be made of bronze in the case where the opposite bearing surface is made of cast iron, steel or a similar metal.

Referring to the accompanying drawings, there will be described below in more detail an illustrative and non-limiting embodiment of the subject of the invention; on the drawings:
Figure 1 is a partial axial section of an orientation bearing arrangement according to the invention, in the assembled state;
Figure 2 is a section similar to that of Figure 1, after disassembly of the two upper partial rings of the outer ring and the radial bearing;
Figure 3 is a section similar to that of Figure 3 after disassembly of the three upper partial rings of the outer ring and the rolling stop.

 The orientation bearing arrangement as illustrated in FIG. 1 comprises, between a fixed external chassis 1 and a movable internal chassis 2, an orientation bearing allowing rotation of the chassis 2 around a vertical axis not shown located on the right of figure 1. The orientation bearing comprises an outer ring 3 fixed to the frame 1 by bolts of which only the axes 4 are shown, and an inner ring 5 fixed to the frame 2 by bolts of which only the axes 6 are represented.

 The outer ring 3 is subdivided in the axial direction into four partial rings 3a, 3b, 3c, 3d and the inner ring is subdivided in the axial direction into two partial rings 5a and 5b.

 The orientation bearing is intended to support a load applied from top to bottom to the inner chassis 2, axially or with an offset from the axis by a maximum distance equal to 50% of the diameter of the bearing. The slewing bearing is also intended to support a radial load.

 The axial load is supported by a rolling stop formed by a row of rollers 7 rolling between two added tracks 8a, 8b, cage sectors 9 ensuring the positioning of the rollers 7. The upper track 8a bears against the partial ring Sa upper of the inner ring 5 and the lower track 8b bears on the lower partial ring 3d of the outer ring 3.

 The radial load is supported by a radial bearing composed of a row of rollers 10 rolling between tracks 1a, 1 lb attached, the outer track 1 carrying it against the partial ring 3b which, in the outer ring 3, is the second from the top, and the inner track 1 lb bear against the upper partial ring -Sa of the inner ring 5. Cage sectors 12 ensure the positioning of the rollers 10.

 Seals 13 and 14 seal the slewing bearing. The partial rings 3a to 3d and 5a, 5b are sealed together by static seals or by a sealing paste.

 The lower partial ring 3d of the outer ring 3 extends radially inward beyond the inner edge of the outer frame 1 and beyond the outer edge of the inner frame 2, so as to cover the upper face of the frame here. interior 2.

Radially opposite the partial ring 3d, the lower partial ring 5b of the inner ring 5 has a reduced diameter, namely less than the outside diameter of the inner frame 2 and slightly less than the inside diameter of the partial ring 3d.

 Sliding pads 15 are attached, for example by welding or the like, to the underside of the partial ring 3b, in the part of the latter covering the upper face of the inner frame 2.

 Sliding pads 16 are attached in the same way in the outer face of the partial ring 5b, opposite the partial ring 3d.

 The pads 15 and 16 which may for example be made of bronze or another anti-friction material are, in the operating position of the orientation bearing arrangement, separated by a small distance of the order of for example 0.5 to 1 mm, some axially from the upper face of the frame 2 and others radially from the inner face of the partial ring 3d.

 In the event that, accidentally, an axial load directed from the bottom up or else an axial load directed from top to bottom, but with too great an eccentricity, is applied to the internal frame 2, the latter lifts very slightly until it comes into contact pads 15. These accidental loads are then transmitted directly from chassis 2 to chassis 1 by the partial ring 3d.

 The orientation bearing composed of rings 3 and 5 and rows of rollers 7 and 10 forming one stop and the other radial bearing can in particular be a large diameter bearing installed in a complex environment for a very long period ( for example from 10 to 20 years). In the event of an incident on the bearing, the complete disassembly of the bearing would be very long and very costly, requiring at least partial disassembly of the installation in which the bearing is incorporated. I1 would also cause, for the user, a shutdown of the installation and therefore operational losses.

 To avoid such a complete disassembly of the bearing, it is provided that the internal parts of the bearing can be inspected, or even be disassembled and changed without requiring complete disassembly of the bearing, the latter remaining operational.

 Referring to Figures 2 and 3, we will describe below the sequence of partial disassembly, inspection, repair or possible replacement and reassembly.

 After radial setting of the partial rings 3c and 3d, and removal of the bolts 4 for fixing the outer ring 3, it is possible to remove the partial ring 3a and the seals 1.

 This allows access to the radial bearing and to check the condition of the rollers 10 and the tracks 1 la and 1 lb. If necessary, it is possible to remove all or part of the rollers 10 with the corresponding cage sectors 12 to check in detail the condition of these rollers 10 as well as that of the tracks 1a, 1lb.

 To have access to the rolling stop and check its condition, the partial ring 3b is removed, which means that under the effect of the radial load, the pads 16 of the inner ring 5 come to bear against the partial ring 3d itself wedged radially. The bearing therefore remains operational, the axial load being supported by the rollers 7 and the radial load by the pads 16.

 If damage is found on the rolling bearing, it can be repaired without completely removing the slewing bearing. Of course, during this operation, the installation in which the orientation bearing is incorporated is taken out of service.

 For this, the inner chassis 2 is raised on a sector, in order to release the rollers 7 here.

 The rollers 7 thus released on a sector can be disassembled with the corresponding cage sectors 9.

 This allows access to tracks 8a, 8b which can be inspected and, if damaged, be repaired or replaced.

 This step-by-step operation allows verification and repair or replacement of tracks 8a, 8b, by sectors or as a whole, without dismantling the installation.

 The bearing is reassembled in the opposite direction, namely by placing, in order, rollers 7, their cage sectors 9 and their tracks 8a, 8b, partial rings 3c, 3b, rollers 10 , their cage sectors 12 and their tracks 11a, 1b, and finally the partial ring 3a and the seals 1.

 It goes without saying that the embodiment described and shown has been given only by way of nonlimiting illustration and that numerous modifications and variants are possible within the framework of the invention.

 Thus, the outer frame, instead of being fixed, can also be movable relative to the fixed inner frame, which implies that the outer ring of the orientation bearing is supported by the row of rollers forming a stop on the inner ring , therefore the use of an inverted orientation bearing.

 Furthermore, to simplify disassembly, it may be advantageous to subdivide one and / or the other of the two rings of the orientation bearing in the circumferential direction into several sectors, as proposed in a patent application filed at the same date this application is made on behalf of the applicant.

Claims (6)

 1. Orientation bearing arrangement comprising two frames (1, 2) one of the two chosen being fixed and the other movable, and an orientation bearing comprising  an inner ring (5) and means (6) for fixing it to the upper face of a first (2) of the frames,  an outer ring (3) and means (4) for fixing it to the second chassis (1),  a row of rolling elements (7) disposed between the two rings (3, 5) to form a rolling stop transmitting to the fixed frame (1) the axial loads applied from top to bottom to the movable frame (2), and  a row of rolling elements (10) disposed between the two rings (3, 5) to form a radial bearing transmitting to the fixed chassis (1) the radial loads applied to the mobile chassis (2),  characterized in that the outer ring (3) has, below the row of rolling elements (7) forming a rolling stop, a lower part (3d) having an inner diameter less than the outside diameter of the first frame (2) and comprising a lower bearing surface (15) located at a small axial distance above an upper bearing face of the first frame (2).  2. Arrangement according to claim 1, the outer ring (3) being axially subdivided into several partial rings (3a to 3d) removable to allow access to the internal parts of the bearing, characterized in that the lower partial ring (3d) has an inner bearing surface located at a short radial distance outside an outer bearing surface (16) of the inner ring (5).  3. Arrangement according to claim 1 or 2, characterized in that one of said bearing surfaces is formed by one or more sliding pads (15, 16) reported.  4. Arrangement according to claims 1 and 3, characterized in that the support pad (s) (15) is (are) attached (s) to the outer ring (3)  5. Arrangement according to claims 2 and 3, characterized in that the or the support pads (16) is (are) attached (s) on the inner ring (5).  6. Arrangement according to any one of claims 3 to 5, characterized in that the support pads (15, 16) are made of bronze.