The present invention relates generally to bearing block assemblies for large rotating tubular members such as agricultural implement rockshafts and, more specifically, to wear insert structure with a thrust surface for such assemblies.
Round steel rockshafts of tubular or solid cross section are commonly utilized to control height on implement frames and disk gang attachments. Bearing block assemblies typically support the shaft from a frame, and a hydraulic cylinder rotates the rockshaft to raise and lower the frame or gang. The bearing block assemblies include a two-piece cast iron or welded steel bearing block which allows rotation about an axis but limit movement in the direction of the axis. As the rockshaft rotates, often under very heavy loading, wear occurs between the steel rockshaft and the metallic bearing block. Although the bearing blocks often include a grease fitting for lubrication to reduce the wear, the hostile operating environment results in contamination of the lubricant with dust and sand which accelerates the wear. To purge the contaminants from between the rockshaft and bearing block, frequent over-greasing is required to discharge the contaminants. This greasing process is often inconvenient because of the location of the assemblies in hard to reach areas and is time-consuming and messy.
A further problem inherent with many bearing block assemblies for large applications such as agricultural implement lift systems is one of manufacturing tolerances of the shafts and of the cast iron or welded steel bearing blocks. A loose or sloppy fit between the mating parts resulting from the tolerances, combined with excessive wear that is commonly encountered in the hostile operating environment, can result in functional problems for the lift systems. Rotating rockshafts retained by bearing blocks have high wear points between the contact members. This wear requires maintenance at a prescribed interval to lubricate these joints to reduce the wear and maintain smooth operation.
Some implements use a one piece plastic liner to reduce wear. However, the one piece liner is difficult to replace if worn or damaged. In commonly assigned U.S. Pat. No. 6,932,512, a two-piece wear insert is described for eliminating greasing and reducing friction between the rockshaft and bearing block. The two-piece liner is easier to replace than a one-piece liner. However, such a liner does not provide thrust protection to accommodate side loads on the rockshaft and reduce friction and noise generated from the side loads.
It is therefore an object of the present invention to provide an improved bearing block structure for agricultural implement lift systems that overcomes most or all of the above mentioned problems. It is a further object to provide such a structure with a liner that is easy to replace and yet provides thrust load protection.
It is another object of the invention to provide an improved bearing liner for an implement bearing block assembly. It is a further object to provide such a liner which is easier to replace and has improved thrust protection and noise reduction compared to most presently available bearing liners.
A bearing block assembly for an implement lift system includes a liner having a two piece ring of low friction material extending around the rockshaft and held in place by a bearing block. The rockshaft includes a radially projecting member interacting with the bearing block assembly to maintain the axial position of the rockshaft. The bearing liner includes a flange seated in a side groove of the bearing block and extending beyond the bearing block to contact the projecting member. The flange and side groove along with a central liner rib and corresponding central bearing block groove locate and support the liner in the proper position. The flange lowers the coeffiecient of friction at the rockshaft/thrust surface interface. The liner design therefore not only reduces or eliminates maintenance brought about by rotational motion and load but also protects from thrust loading along the rockshaft axis. The low friction flange also reduces thrust load noise and provides smoother rockshaft action. The low coefficient of friction of the insert material maintains smooth, quiet rockshaft operation and addresses frictional wear problems in all planes of contact at the bearing interface. The liner can be replaced easily without need to dismantle the entire lift system
These and other objects, features and advantages of the present invention will become apparent from the description below in view of the drawings.
Referring to
The bearing block assemblies 22 include a first or bottom portion or half section 40 (
The bearing block assemblies 22 include bearing block liners or wear inserts 70 which, as shown in
The wear inserts 70 include a central rib 74 (
Radially projecting anti-rotation flanges 84 extend between the opposite thrust flanges 76 at the ends of the inserts 70. The flanges 84 are connected to and extend radially outwardly from the thrust flanges 76 and the central rib 74. As best seen in
Referring to
The wear inserts 70 and the first and second bearing block portions 40 and 42 are assembled around the rockshaft 20, and the connector structure 24 is tightened against the main frame tube 12t to secure the bearing block portions around the rockshaft and support the rockshaft from the frame 12. As shown, the connector structure 24 includes a bolt 124 extending through each pair of aligned bores 62. The bolts 124 extend upwardly adjacent opposite faces of the tube 12t and through apertures in an upper mounting plate 126. Upper threaded ends of the bolts 124 receive nuts tightened against the mounting plate 126 to secure bearing block portions 40 and 42 together around the inserts 70 and to draw the flat 66 on the portion 42 tightly against the lower face of the main frame tube 12t.
To replace the wear inserts 70, the operator simply loosens or removes the bolts 124 to open up the bearing block portions from around the rockshaft 124 sufficiently to remove the individual semi-circular wear inserts 70 from the cavities. New inserts 70 are then placed in the cavities 50 and 52, and the bolts 124 are tightened to rotatably secure the rockshaft 20 in position on the frame 12. Maintenance of the bearing structures therefore is relatively simple and does not require dismantling of the implement lift system.
The rockshaft 20 includes thrust structure indicated at 130 extending radially outwardly from the circular cross-section of the rockshaft. The thrust structure 130 is located adjacent the bearing block sections 40 and 42 and includes an axially inwardly facing thrust surface 136 which, when the bearing block sections are assembled around the rockshaft 20, abuts or is closely adjacent the outwardly facing flat wear surface 78 on the thrust flange 76 of the wear insert 70 (
Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere & Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere & Company or otherwise.