Joints and connections – Member deformed in situ
Patent
1992-05-07
1994-04-05
Reese, Randolph A.
Joints and connections
Member deformed in situ
403273, 403242, 74567, 294321, F16H 5300
Patent
active
052998819
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a connection of a shaft manufactured to final dimensions and at least one cam surrounding the shaft in an annular manner and manufactured to final dimensions and processes for manufacture thereof.
The statements below relate to a camshaft for controlling valves, such as those used in internal combustion engines. However, the invention does not relate only to camshafts but can also be used wherever production costs and quality advantages are involved.
BACKGROUND OF THE INVENTION
A camshaft must meet various requirements; it must have good flexural strength, torsional strength and fatigue strength, but in particular the cam must be hard-wearing. The counter-part in direct contact with the cam is differently designed depending on the engine. The pinion partners used today for the cam are tappets, drag levers and valve lifters, in which sliding friction occurs, and roller tappets and roller lifters in which a rolling movement occurs.
The high forces which occur in the drive system and which act on the pinion partners exert various pressures on the contact surfaces of the pinion partners, which may cause damage in the case of an unsatisfactory design of the pinion partners, in particular at their surface (pitting, abrasion, etc.).
In systems where there is a sliding movement between the pinion partners in addition to high pressure, it must be ensured that the sliding surfaces of the cam additionally have an adequate wear-resistant layer to prevent abrasion of the cam.
The cast iron or clear chill cast iron camshafts used today are designed as one piece. These components, which in principle are proven ones, have the disadvantage that there are high processing costs, in particular in the operations such as cam grinding, thermal treatment, alignment, etc. and high spoilage rates in production from the blank to the ready-to-install camshaft. Another disadvantage is the high weight of the camshaft designed as a solid shaft. Modern surface coating processes for reducing wear are unsatisfactory because of the price and for technological reasons.
Patent publications have disclosed that attempts have been made to replace the present one-piece cast iron or clear chill cast iron camshafts with a multi-piece steel camshaft. This version was intended in particular to achieve a weight reduction through the use of a hollow shaft (pipe). In certain constructions, lower production costs were also expected.
All known multi-piece camshafts have in common the fact that the cast blank of the one-piece camshaft is replaced with a multi-piece steel camshaft blank. In the case of the production costs, a certain saving is achieved in the machining costs. The expensive finishing of the end position, the bearing seat and cams is, however, still part of the existing production technology. Here too, surface coating processes for improving wear are unsuccessful for technological reasons (size, selective area).
All joining methods disclosed, i.e. the joining of the cam to the shaft without torsion and axial displacement, have the disadvantage that, owing to the joining technology chosen, the required final geometric state of the mounted camshaft is not achieved without further machining.
The prior publication DE 3717534 A1 describes a constructed camshaft in which a relatively uncontrolled pressure build-up takes place in the cam as a result of widening the hollow shaft from inside--as found in practice--and acts as far as the cam surface by transmission via the points adjacent to the shaft, and irregularities, for example central indentations, may form there. This important disadvantage on the one hand prevents the use of cams machined to final dimensions and on the other hand prevents the use of novel production and surface coating processes.
A possible method for producing the cams and hollow shaft to final dimensions, including wear layer, prior to assembly would permit a considerable reduction in the unit costs compared with the conventional cast iron camshafts and also compared with the multi-piece assembled
REFERENCES:
patent: 683656 (1901-10-01), Moyle
patent: 1329479 (1920-02-01), Savon
patent: 1949678 (1934-03-01), Doran
patent: 1983867 (1934-12-01), Miller
patent: 3603624 (1971-09-01), Attermeyer
patent: 4513488 (1985-04-01), Arena
patent: 4523872 (1985-06-01), Arena
patent: 4631973 (1986-12-01), Eley
patent: 4675204 (1987-06-01), Nicoll
patent: 4681642 (1987-07-01), Nonoyama
patent: 4704074 (1987-11-01), Kawamoto
patent: 4767233 (1988-08-01), Erickson
patent: 4809562 (1989-03-01), Bendoraitas
patent: 4899615 (1990-02-01), Matt
patent: 4905538 (1990-03-01), Watanabe
Knight Anthony
Reese Randolph A.
LandOfFree
Assembly of a cylindrical body made to finished dimensions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Assembly of a cylindrical body made to finished dimensions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Assembly of a cylindrical body made to finished dimensions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-507381