US 5,207,120 A · Assembled crankshaft

Abstract

A tubular shaft has a portion of reduced inner diameter at a location where joining to an apertured member is desired. The aperture in the member is lobed with splines in the lobes and has an undercut groove, or groove and is hardened. The shaft is inserted in the aperture and the reduced inner diameter portion is expanded to force the shaft material into the lobes and groove and around the splines to form a connection which resists torque and axial separation. The tube expansion is effected by forcing a series of balls through the reduced diameter portion, each ball being slightly larger than the reduced diameter and larger than the previous ball but smaller than the remainder of the shaft I.D. A crankshaft is assembled with this method wherein counterweights have lobed apertures to receive end portions of crank pins and main journals having reduced I.D.'s. Lubricating passages are formed in crankshafts having main journals and crank pins with reduced end portions defining planar shoulders on their body portions and annular grooves on the shoulders, bores in the crank arms intersecting the annular grooves on the adjacent shoulders, and passages in each bearing and crank pin connecting its annular groove with the surface thereof.

Claims15

Dependent claims

A crankshaft assembled from individual preformed parts which are finish machined prior to assembly comprising:

a plurality of main journals aligned on a crankshaft axis of rotation;
a plurality of tubular crank pins between the main journals and radially spaced from the crankshaft axis, each crank pin having a surface hardened body portion and non-hardened end portions, the end portions each having a smaller inner diameter than the body portion;
a plurality of crank arms each having a center aperture aligned on the said crankshaft axis for receiving an end portion of a main journal, the crank arms being securely attached to end portions of respective main journals for torque transmission between the main journals and the crank arms;
an off-axis aperture in each crank arm adjoining a crank pin for receiving an end portion of a crank pin, each off-axis aperture having a lobular cross section with a plurality of lobes;
and
each end portion of a crank pin tightly conforming with the respective off-axis aperture for secure attachment to the respective crank arm.

3 more elements

Dependencies are inferred from the claim text.

Assembled crankshaft

Life of this patent

Assembled crankshaft

Life of this patent

Abstract

Claims15