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Connecting Rod

Posted in Uncategorized by admin on July 9, 2011

Connecting Rod

Method for producing a connecting rod for a radial piston motor

A connecting rod for a radial piston motor including a spherical surface portion, a rod portion and a pad portion having a sliding surface. The spherical surface portion, rod portion and pad portion are formed integrally, and the sliding surface has a bearing alloy attached to its surface by centrifugal casting.

An overlay may be provided on the bearing alloy. The connecting rod is produced in a mass production basis by a method including the steps of integrally forming a star-shape cylindrical monolithic blank having a single cylindrical centrally located axial opening and bearing six equally spaced outwardly radiating rod portions, each rod portion bearing an integral, substantially spherical surface portion on its distal end; attaching a bearing alloy by centrifugal casting, to the centrally located axial opening in said blank; machining the surface of the bearing alloy; and dividing the blank into six pieces constituting six connecting rods. The machined surface of the bearing alloy may be provided with an overlay, such as a Pb-base alloy.

This invention relates to a connecting rod including a spherical surface portion, a rod portion and a pad portion for a radial piston motor suitable for use with watercraft, concrete mixers, etc., and a method of producing same.

This type of connecting rod has hitherto been produced, as shown in FIG. 1, by first forming a spherical surface portion 1, a rod portion 2 and a pad portion 3 having a sliding surface 5 integrally with one another (to provide a blank 4) as by alost-wax precision casting process, and then applying a lining of white metal bearing alloy to the sliding surface 5 (of arcuate shape as shown in FIG. 3 et seq.) of the pad portion 3 by pouring molten alloy thereon. Owing to the complex shape of theconnecting rod, a casting process used for applying a white metal bearing alloy becomes complex in construction, thereby increasing cost and making it difficult to obtain a bearing alloy of highly compact and uniform structure because difficulties areencountered in effecting uniform cooling which is one of the conditions for casting that should be met. Thus a bearing alloy having a lining applied thereto by pouring molten alloy, such as molten white metal bearing alloy, on the sliding surface of thepad portion has tended to have segregated thereon acicular crystals (Cu6 Sn5) and cubic crystals (SbSn), which are hard and bittle intermetallic compounds, and to have coarse crystals formed thereon.

Before and after the blank 4 has a lining applied to the sliding surface 5 of the pad portion 3 by pouring molten alloy thereon, the blank is machined individually to have its inner diameter finished. This has made it necessary to use amachining and holding device of a complex shape. Thus the time required for machining such workpiece has been long and no stability has ever been obtained in the precision with which the workpiece is finished. When an overlay is applied to the bearingalloy as required, each workpiece has to be treated individually, and this has made it necessary to use an expensive device of complex construction and perform a time-consuming operation. Yet it has hitherto been difficult to provide an overlay ofuniform thickness.

From the foregoing description, it will be appreciated that the method for producing a connecting rod according to the invention offers the advantage that the connecting rods can be produced on a mass production basis, and that the connectingrods produced by the method according to the invention is better in quality than connecting rods of the prior art.

In a radial piston motor transmission the deep diving or entering piston shoe is utilized and swingably borne in the pivot-bed of the radially reciprocating piston.Since deep diving piston shoes have large piston strokes, the shoes pivot in the pistons in large angles.Thereby a considerable force-portion of the load on the piston is transfered to the wall between the piston and the cylinder, whereby heretofore short pistons produced occasionally welding and sticking between the cylinder wall and the piston wall.The piston therefore receives radially extending portions, which may extend beyond the medial portions of the piston show and may even enter into the ring groove of the piston stroke actuator ring. Thereby a very long guidance of the piston on cylinder wall portions is obtained, which makes the application of effective pressure balancing pockets at correct location between piston wall and cylinder wall possible. An extended piston guide and friction--less travel of the piston in the cylinder without wearing or sticking is assured.

This invention has been developed for the purpose of obviating the aforesaid disadvantages of the radial piston motor art. Accordingly, the invention has as its object the provision of a connecting rod for a radial piston motor and a method of producing samewhich has the features and offers the advantages that are set forth hereinafter.

About the Author

Zhongyi Hydraulic Motor Company is a professional engaged in radial piston motor,axial piston motor,slewing transmission,danfoss motor,hydraulic orbital motor,hydraulic steering unit. All products are strictly tested before delivery by testing bench and comprehensive testing facilities to ensure the quality.

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