A method of manufacturing a crankshaft includes the steps of: (1) forming a crankshaft blank via a first half and a second half; (2) measuring a plurality of surface variations between a predetermined surface in a first region and a corresponding predetermined surface in a second region of the crankshaft blank; (3) calculating centering offset data based on the plurality of surface variations; (4) machining a pair center holes based on the centering offset data; (5) machining a counterweight and a journal relative to the pair of center holes to produce a partially machined crankshaft; (5) milling and grinding the partially machined crankshaft to produce a finished machined crankshaft; and (6) rotating the finished machined crankshaft typically on the outermost main journals in a final balancing machine and then modifying the counterweights to eliminate undesirable vibration generated during the rotation and engine operation.

A machining tool for deburring boreholes, which lead laterally into a recess, comprising: a shaft; a cutting head with at least one circumferential cutting blade associated with a chip groove and having a cutting edge extending, at least in sections, in an axial direction, and which can perform a cutting process by virtue of relative movement between the tool and a workpiece, and which lies on a virtual cylindrical rotation surface; and at least one cutting-blade-free and chip-groove-free surface area; at least one fluid channel closed on the cutting head side, extending through the shaft into the cutting head; and at least one branch channel with an outlet opening. The outlet opening is in a dynamic pressure active surface radially set back relative to the virtual rotation surface, and is larger than a flow cross-sectional area of the at least one branch channel at the outlet opening.

A forged crankshaft assembly for an engine, and a method of manufacturing the same, has a forged crankshaft and a removable counterweight to provide access for core drilling or milling a cavity. The forged crankshaft has a pin bearing journal, a main bearing journal, a first crank arm supporting the pin bearing journal, a second crank arm supporting the pin bearing journal and connecting the pin bearing journal and the main bearing journal, and at least one milled crank arm cavity formed within at least a portion of the second crank arm. The removable counterweight extends radially outward from the first crank arm, wherein the crank arm cavity is configured to be accessible to a core drill or mill cutter only when the removable counterweight is removed from the first crank arm and inaccessible to the core drill or mill cutter when the removable counterweight is coupled to the first crank arm.

A chip-removing tool for deburring bores, which laterally open into a cylindrical recess for example, comprising a shaft; a cutting head with at least one cutting wedge on the circumference, said cutting wedge being paired with a flute and having a cutter, which extends in an axial direction at least in some sections, carries out a cutting process on the basis of a relative movement between the tool and a workpiece, and lies on a virtual cylindrical rotational surface with a diameter that corresponds to the nominal diameter of the chip-removing tool, and at least one cutting wedge- and flute-free surface region; at least one fluid channel closed on the cutting head side and extending through the shaft and into the cutting head; and at least one puncture channel which starts from the fluid channel and comprises an opening that lies in the cutting wedge- and flute-free surface region.

A forged crankshaft assembly for an engine, and a method of manufacturing the same, has a forged crankshaft and a removable counterweight to provide access for core drilling or milling a cavity. The forged crankshaft has a pin bearing journal, a main bearing journal, a first crank arm supporting the pin bearing journal, a second crank arm supporting the pin bearing journal and connecting the pin bearing journal and the main bearing journal, and at least one milled crank arm cavity formed within at least a portion of the second crank arm. The removable counterweight extends radially outward from the first crank arm, wherein the crank arm cavity is configured to be accessible to a core drill or mill cutter only when the removable counterweight is removed from the first crank arm and inaccessible to the core drill or mill cutter when the removable counterweight is coupled to the first crank arm.

A crankshaft machining system includes a center hole boring device, a post-centering balance meter and a cutting device. The post-centering balance meter is configured to measure the shape of a post-centering crankshaft blank on the basis of a pair of center holes. Additionally, the post-centering balance meter is configured to set a principal axis of inertia on the basis of the shape of the post-centering crankshaft blank and generate center hole positional information for correction that indicates intersections between the principal axis of inertia and both end surfaces of the post-centering crankshaft blank. The center hole boring device is configured to bore a pair of center holes on both end surfaces of another crankshaft blank to be loaded next on the basis of the center hole positional information for correction.

A crankshaft balancer machine for balancing a crankshafts having a measurement station configured to rotate the crankshaft to obtain vibration-related data, a transfer station configured to transfer the crankshaft between the measurement station and the correction station, and a correction station configured to drill at least a portion of the crankshaft to correct an imbalance in response to the imbalance data. The measurement station includes a base structure, a measurement bridge support, a plurality of flexural support legs extending therebetween, at least one sensor, and a drive system to spin the crankshaft and output imbalance data. The transfer station includes at least one lifting arm selectively engaging the crankshaft and supporting the crankshaft during transfer. The correction station includes a drilling device horizontally disposed to achieve a horizontal drill direction into the crankshaft to correct any imbalance according to a customized software protocol.

A method of manufacturing a crankshaft assembly includes configuring a crankshaft with a crankpin journal having a cavity extending at least partially from a first axial side to a second axial side of the crankpin journal, and opening at at least one of the first axial side and the second axial side. The method includes disposing a core plug in the cavity. The crankshaft has a first density and the core plug may have a second density which may be less than the first density. A crankshaft assembly includes the crankshaft and the core plug.

A crankshaft balancer machine for balancing a crankshafts having a measurement station configured to rotate the crankshaft to obtain vibration-related data, a transfer station configured to transfer the crankshaft between the measurement station and the correction station, and a correction station configured to drill at least a portion of the crankshaft to correct an imbalance in response to the imbalance data. The measurement station includes a base structure, a measurement bridge support, a plurality of flexural support legs extending therebetween, at least one sensor, and a drive system to spin the crankshaft and output imbalance data. The transfer station includes at least one lifting arm selectively engaging the crankshaft and supporting the crankshaft during transfer. The correction station includes a drilling device horizontally disposed to achieve a horizontal drill direction into the crankshaft to correct any imbalance according to a customized software protocol.

Disclosed is a technique of achieving weight reduction of a forged rotary body while improving productivity of the forged rotary body. Temporary center holes are set for each of two or more samples extracted from one forging lot of a plurality of forged rotary bodies produced within a time period after a die misalignment adjustment through before a next die misalignment adjustment. Then, a virtual final shape of each of the samples is simulated on an assumption that machining is performed on the basis of the temporary center holes, and a rotational imbalance amount is calculated. Then, an average value of the rotational imbalance amounts in all of the samples in the same forging lot is calculated, and center-hole positions which allow the average value to become zero are set as center hole machining positions for all of the forged rotary bodies in a corresponding forging lot.