Machine element or mechanism – Elements – Cranks and wrist pins
Patent
1983-06-02
1985-08-13
Dorner, Kenneth J.
Machine element or mechanism
Elements
Cranks and wrist pins
74605, 29 6, F16C 310, F16C 314
Patent
active
045342415
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a crankshaft for combustion engines, comprisng a number of components made with cavities and joined to each other so as to form together main bearing journals, crank bearing journals and counterweights.
It is known to manufacture cranshafts with a number of components with cavities, which are joined together by welding into a complete crankshaft. The components can be preworked to such a degree that only heat treatment and final grinding is required after the welding operation. A crankshaft of this type has several advantages over a conventional homogeneous crankshaft. If the components are forged with cavities which provide an optimum ratio between weight and strength, the weight of the crankshaft can be reduced by about 30-35% in comparison to a conventional crankshaft. Furthermore, both the production of blanks and the machining can be done with simpler and less expensive machines, and furthermore with an appreciably higher degree of automation. The same blanks and machined components can be used for crankshafts in engines with different numbers of cylinders, which further contributes to reducing production costs.
In order to make it possible to exploit the above-mentioned advantages, the oil supply to the bearings must be solved in a satisfactory manner. The problem is that it is difficult to assure that the cavities in the bearing journals will be completely free of contaminants such as shavings, slag or sand from the casting molds. If the oil is permitted to pass through the cavities and out through bores in the bearing journals, there will be the risk that contaminants are carried with the oil to the bearings, possibly destroying them.
One purpose of the present invention is to solve the problem of lubrication and yet retain the possibility described above of preprocessing the components to such a degree that only heat treatment and final polishing remain after welding.
This is achieved according to the invention in that each of the components is made with a portion of a main bearing journal and a portion of a crank bearing journal, and that journal portions joined together form closed cavities in both the main bearing journals and the crank bearing journals, one of two components joined to each other having longer journal portions than the other component and having at least one oil duct delimited from the cavities and extending between the journal portions and opening at their lateral surfaces.
This construction prevents the oil from entering the cavities and carrying contaminants to the bearings, the difference in length of the bearing journal portions on the components making it possible, prior to assembly, to provide one of the components with oil ducts, which after assembly open centrally on the bearing journals and assure an evenly distributed supply of oil to the bearings.
The invention will be described below with reference to examples shown in the accompanying drawings.
FIG. 1 shows a side view, partially in section, of a portion of a crankshaft according to the invention,
FIGS. 2-4 show three different embodiments of one of the components in section along the line A--A in FIG. 1,
FIGS. 5 and 6 show side views, partially in section, of two additional embodiments, and
FIGS. 7 and 8 show cross sections along the line VII--VII and VIII--VIII in FIGS. 5 and 6.
The crankshaft shown in FIG. 1 is made of a number, dependent on the number of cylinders, of pairs of components 1 and 2 and end journals 3. Each component 1 and 2 has, in addition to a counterweight 4 or 5 respectively, a portion 6 or 7 respectively of a hollow main bearing journal 8 and a portion 9 or 10 respectively of a hollow crank bearing journal 11. The bearing journal portions 6 and 9 of component 1 are longer than the bearing journal portions 7 and 10 of component 2 and are provided with radial bores 12, 13 which open into cavities 14, 15 in the bearing journals. By virtue of the fact that the joint between two components 1 and 2 are thus asymmetrical, the bores can be placed in the center of the
REFERENCES:
patent: 2109526 (1938-03-01), Fell
patent: 2256726 (1941-09-01), Rippingille
patent: 3309941 (1967-03-01), Kappel
patent: 3704636 (1972-12-01), Piech
patent: 3748925 (1973-07-01), Stewart
patent: 3768335 (1973-10-01), Mayer
patent: 3772763 (1973-11-01), Henson et al.
Larsson Sten
Remmerfelt Arne
AB Volvo
Dorner Kenneth J.
Luong Vinh
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