6UZ1 Used Crankshaft For Excavator SH460-5 SH450-3B 8-97603046-5

6UZ1 Second Hand Crankshaft For Excavator SH460 - 5 SH450 - 3B 8 - 97603046 - 5

Specification

Description

FORCES IMPOSED ON A CRANKSHAFT

However, the counterweights are not always directly opposite the rod journals. For example, the commonly-used production version of a two-plane 90° V8 crankshaft has no counterweights around the center main journal, as shown in Figure 1 above. In that case, the centroid of each counterweight, instead of being 180° from its respective journal, is offset (to approximately 135°) in order to place the net counterbalancing forces in the optimal location. Note also (in Figure 1) that the front and rear counterweights are larger (thicker) than the others in order to fully counterbalance the end-to-end moments.

CRANKSHAFT MANUFACTURING PROCESSES

Many high performance crankshafts are formed by the forging process, in which a billet of suitable size is heated to the appropriate forging temperature, typically in the range of 1950 - 2250°F, and then successively pounded or pressed into the desired shape by squeezing the billet between pairs of dies under very high pressure. These die sets have the concave negative form of the desired external shape. Complex shapes and / or extreme deformations often require more than one set of dies to accomplish the shaping.

Originally, two-plane V8 cranks were forged in a single plane, then the number two and four main journals were reheated and twisted 90° to move crankpins number two and three into a perpendicular plane. Later developments in forging technology allowed the forging of a 2-plane "non-twist" crank directly.

Crankshafts at the upper end of the motorsport spectrum are manufactured from billets of high-grade alloy steel. Billet crankshafts are fully machined from a round bar ("billet") of the selected material (Figure 4). This method of manufacture provides extreme flexibility of design and allows rapid alterations to a design in search of optimal performance characteristics.  In addition to the fully-machined surfaces, the billet process makes it much easier to locate the counterweights and journal webs exactly where the designer wants them to be. This process involves demanding machining operations, especially with regard to counterweight shaping and undercutting, rifle-drilling main and rod journals, and drilling lubrication passages. The availability of multi-axis, high-speed, high precision CNC machining equipment has made the carved-from-billet method quite cost-effective, and, together with exacting 3D-CAD and FEA design methodologies, has enabled the manufacture of extremely precise crankshafts which often require very little in the way of subsequent massaging for balance purposes.