Abstract Pairs of bearing sections of a crankshaft, each pair comprising a line bearing and an adjacent stroke bearing are machined consecutively starting with a pair close to one end of the crankshaft and proceeding pair by pair towards the other end of the crankshaft. In this operation the section of the crankshaft located between the pair in cutting engagement with the tools and the other end of the crankshaft is left radially upsupported and freely to undergo any deformation that may result from the removal of stock by the tools, whereas the other section of the crankshaft including the pair of bearings machined in the preceding operation is held by engagement with suitable clamping means. As a result of this method any deformation of the character just explained is eliminated by the subsequent machining operation and the end product is free from any deformation. Therefore, it is no longer necessary, as heretofore, to subject the crankshaft after the roughing operation to a truing and finishing operation prior to the heat treatment and the grinding operation.
A method for machining the crank-bearings and line-bearings of a crankshaft comprising the steps of machining pairs of said bearings in successive machining operations, each pair comprising a crank-bearing and an adjacent line-bearing, the bearings constituting each pair being machined simultaneously, commencing said successive machining operation with such one of said pairs that is close to one end of the crank-shaft and proceeding pair by pair towards the other end of the crankshaft and holding the crankshaft during each succeeding machining operation by engagement with clamping means of such bearing surface as has been machined in the preceding machining operation, whereas the bearing surfaces of the pairs to be machined subsequently and said other end of the crankshaft are left unengaged by clamping or centering means and free to undergo radial displacement.
Claim 2
Independent Claim
132 words
A method for machining the crank-bearings and line-bearings of a crankshaft comprising the steps of machining pairs of said bearings in successive machining operations, each pair comprising a crank-bearing and an adjacent line-bearing, the bearings constituting each pair being machined simultaneously, commencing said successive machining operation with such one of said pairs that is close to one end of the crank-shaft and proceeding pair by pair towards the other end of the crankshaft and holding the crankshaft during each succeeding machining operation by engagement with clamping means of such bearing surface as has been machined in the preceding machining operation, whereas the bearing surfaces of the pairs to be machined subsequently and said other end of the crankshaft are left unengaged by clamping or centering means and free to undergo radial displacement.
Claim 3
Dependent Claim
29 words
A method as claimed in claim 1 in which the first line-bearing and the last crank-bearing do not form part of one of said pairs and are machined individually.