AU657198B2 - Oil bath spherical roller bearing and seal system for disc harrows - Google Patents

Description

Our Ref: 457509 657198 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

D

o Applicant(s): Address for Service: Invention Title: Joseph Roy Carr P 0 Box 1830 DUBBO NSW 2830

AUSTRALIA

Rodney Joseph Squire Carr P 0 Box 1830 DUBBO NSW 2830

AUSTRALIA

DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Oil bath spherical roller bearing and seal system for disc harrows a full description of this invention, including the .t known to me:- The following statement is best method of performing i 5020 -1- This invention relates to bearing arrangements and in particular bearing arrangements in agricultural machinery such as disc harrows, However the invention is applicable to any device having a shaft rotating in a bearing.

Disc harrows have a number of sets of discs mounted onto a main frame which in turn is connected to a tow vehicle, usually a tractor. Each set of discs is mounted upon an axle which in turn is rotatably supported on the main frame, or a sub-frame, typically by tapered roller bearings. Each axle may have, for example, five to sixteen discs mounted along its length and may be supported by bearings at various points along its length. Tapered roller bearings provide only minimal tolerance for miss-alignments so, unless the axle is substantially straight and the bearings are aligned, unnecessary forces acting on the bearings are generated, leading to early bearing failure.

15 In an attempt to overcome the disadvantages of the prior art the invention uses spherical bearings to support the axle. Since the axis about which a spherical bearing rotates may vary somewhat, this provides in-built tolerance of miss-alignment or bent axles. The invention also includes provision of a seal which permits the spherical bearing to run in a sealed oil bath, which greatly improves the life expectancy of the bearing.

*20 Accordingly in one broad form the invention provides an agricultural implement comprising: a frame; a plurality of bearing assemblies mounted on the frame; at least one axle mounted on the bearing assemblies for rotation about its axis; at least one ground engaging component mounted on the at least one axle for rotation therewith; wherein each of the bearing assemblies comprises a tubular housing within which a spherical bearing is mounted in a sealed oil bath, a sleeve assembly mounted on the axle for rotational engagement with the bearing assembly, the sleeve assembly having a sleeve extending beyond the axial ends of the housing and end caps mounted on the sleeve at each end thereof so as to define an annular space between the housing and the end caps, and seals on each axial side of the bearing between the end caps and the A L/ housing to seal the annular space.

U 3 -p:\wpdoes\sab\457509.spe\dht 'A T? 0758k/lfg -2- The invention shall now be described with reference to the drawings of a non-limiting embodiment in which: Fig. 1 is an axial cross-sectional view of a bearing arrangement according to the invention.

Fig. 2 is an exploded axial cross-sectional view of the embodiment of Fig. 1.

Fig. 3 is an end view of the embodiment of Fig. 1 in which parts have been omitted for clarity.

Referring to the drawings each bearing assembly includes a bearing housing 11. Each bearing housing 11 is a generally hollow circular tube 12 having an external mounting bracket 13 by which the tube 12 is mounted to the main or sub-frame (not shown). Preferably, for ease of manufacture the tube 12 and bracket 13 are separate units welded together, as indicated by fillet welds 14.

Preferably the bracket 13 is provided with holes 15 through which suitable fixing means, such as bolts, may pass to secure the bracket to the main or sub-frame.

Located approximately centrally within the tube 12 is a spherical bearing 20, arranged coaxial with the tube. The bearing is located axially within the tube 12 by abutting a step 21 in the inner wall 22 at one axial end face 23. The inner wall 22 is provided with an annular groove 24 adjacent the other axial end face 25 of the bearing and a circlip 26 is located in the groove 24 to securing the bearing in position. It will be appreciated that the bearing 20 is an interference fit within the tube 12 so that the outer shell does not rotate.

Passing through the bearing 20 and snugly engaging the bearing's inner shell in an interference fit is a hollow bearing centre shaft 30 which extends beyond the axial ends 31, 32 of the tube 12. The bearing centre shaft 30 has an 0758k/lfg 3 inner surface 33 of constant cross-section. However its outer surface has two end sections 34, 35 of the same diameter and an intermediate section 36 of greater diameter. The change in diameter between the intermpdiate section 38 and the end sections 34, 35 is abrupt so as to define two annular surfaces, 37, 38, perpendicular to the shaft axis.

The bearing centre shaft 30 is positioned with its annular face 37 abutting the axial end face 25 of the inner shell of the bearing 20 and the other annular face 38 at a position beyond the end 32 of the housing 11.

A "concave" end cap 40 is mounted on the end section The end cap 40 is generally disc shaped having a central bore 41 therethrough. The bore 41 is sized so as to form an interference fit with the end section 34. The end cap 40 is positioned so its inwardly facing end 42 abuts the annular face 38. The bore 41 is provided with an annular groove 43 in which an O-ring 44 is located to provide a seal. Although the concave end cap 40 and end section 34 36 form an interference fit, for additional security there is provided a radially extending bore 45 in the end section 34 and a corresponding radially extending bore 46 in the end cap 40 into which a roll pin 47 is located, thereby preventing relative axial and circumferential movement of the two parts.

The end 42 of the end cap 40 is provided with two concentric bores 48, 49. The inner bore 48 is of the same diameter as the end of the housing and extends towards the housing so there is a small gap 50 therebetween. The outer bore 49 has a diameter greater than the outer surface of the housing 11 and extends to overlap the lousing 11.

Located within the housing 11 adjacent to the circlip 26 is a ring shaped seal retaining ring 60. The seal retaining ring 60 engages the inner surface of the housing 11 and has a bore of larger size than the centre shaft passing therethrough. Located adjacent the outer axial end face 51 of the retaining ring 60, the inner face of the housin t is provided with a step in its diameter so as to 0758k/lfg 4 form an outwardly facing annular face 52. This face is co-planar with the face 51 of the retaining ring A two part seal 65 is provided to seal the gap between the end cap 40 and the housing 11. Each part 66, 67 is identical and comprises a resilient ring 70 and a metal ring 71 having an L-shape in cross-section. The resilient ring snugly and firmly passes over the metal ring 71 so as to form a single un' A first part 66 is located in the housing to sealingly engage the inner surface and the faces 51, 52. The other part 67 engages within the bore 48 and against the end face 42. The metal rings 71 of each part abut and provide a seal.

Mounted on the other end part 34 of the centre shaft is a "convex" end cap 75 having a disc shape. A centrally located bore 76 extends through the end cap 75 and snugly receives the centre shaft 30 in an interference fit. As with the concave end cap 40, the end portion 35 and convex S end cap 75 are provided with radially extending bores 77, 78 into which a second roll pin 79 is inserted to prevent relative movement therebetween. The central bore 76 is also provided with an annular groove 80 in which a second 0-ring 81 is located to seal the joint between the centre shaft and the convex end cap The inner portion 82 of the convex end is shaped similarly to the inner portion 42 of the concave end i.e, it is provided with two concentric bores 83, 84 and as with the concave end cap the first bore 83 is the same diameter as the inner diameter of the corresponding end of the housing 12 and extends to leave a small gap therebetween. The outer bore 84 is of greater diameter than S the outer diameter of the end of the housing 12 and extends over the gap to overlap the housing 12.

The inner-surface of the housing 12 is stepped to provide an annular surface and a second seal 90 engages the end portion 35 and convex end cap 75 in a similar manner to the concave end cap A tubular thrust spacer 92 is provided around the centre shaft 30 between the convex end cap 75 and the 0758k/lfg spherical bearing 20. When assembled the thrust spacer 92 firmly abuts against the convex end cap 75 and the inner shell of the bearing 20 to transfer thrust.

In use a plurality of the bearing assemblies are positioned on the main or sub-frame substantially in line.

A disc 100 is placed adjacent the outer surface 101 of each convex end 75 and sandwiched between the convex end 75 and a spool 102. Similarly a disc may be sandwiched between a spool (not shown) aid the outer surface of the concave eni or between two spools 102. A large retaining bolt (net shown), which acts as an axle is then passed centrally through the spools, discs and bearing assemblies and tightened to firmly secure the components together. It will be appreciated that in agricultural machinery the bearing assemblies may not all be aligned perfectly. Thus the use of the spherical bearing automatically compensates for this, thereby preventing abnormal loads on the bearing and premature failure.

Preferably the bearing assembly is an oil bath type assembly in which the bearing and seals run in an oil bath, as opposed to Ln assembly in which the bearing is lubricated S" by grease. Use of an oil bath enables both the bearing and seals to be adequately lubricated, which further enhances the durability and longevity of the bearing and seals.

Further, since the bearing assemblies 10 are removably mounted to the main or sub-frame of the harrow by bolts passing through mounting holes 15, it is possible to reverse the bearing assemblies Whilst the embodiment has been described with reference to fully concave discs, this is not an essential feature and the invention having a flat centre section may be used with discs. This, of course, will require the use of end caps having a corresponding flat section to mate with these discs.

It will be appreciated that while the invention has been described with reference to a disc harrow the invention is not limited to a disc harrow and is applicable to other machinery.

It will be appreciated by those skilled in the art that

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d I *0758k/lfg -6many modifications and variations may be made to the embodiments described herein without departing from the spirit or scope of the invention.

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Claims (4)

1. An agricultural implement comprising: a frame; a plurality of bearing assemblies mounted on the frame; at least one axle mounted on the bearing assemblies for rotation about its axis; at least one ground engaging component mounted on the at least one axle for rotation therewith; wherein each of the bearing assemblies comprises a tubular housing within which a spherical bearing is mounted in a sealed oil bath, a sleeve assembly mounted on the axle for rotational engagement with the bearing assembly, the sleeve assembly having a sleeve extending beyond the axial ends of the housing and end caps mounted on the sleeve at each end thereof so as to define an annular space between the housing and the end caps, and seals on each axial side of the bearing between the end caps and the 15 housing to seal the annular space.

2. The implement of claim 1 wherein the or each ground engaging component is mounted on the axle, sandwiched between two spools or between a spool and the sleeve assembly.

3. The implement of claim 2 wherein the end caps have faces complementary to the at least one ground engaging component.

4. An agricultural implement substantially as herein described with reference to the drawings. DATED this 25th day of November, 1994. JOSEPH RODNEY CARR By their Patent Attorneys DAVIES COLLISON CAVE T p:\wpdocs\sab\457509.spc\dh 0758k/lfg ABSTRACT The invention is an agricultural implement such as a disc harrow comprising a frame, a plurality of bearing assemblies (10) mounted on the frame, at least one axle mounted on the bearing assemblies (10) for rotation about its axis, and at least one ground engaging component (100) mounted on the at least one axle for rotation therewith, wheziin each of the bearing assemblies comprises a spherical bearing