The power end assembly mainly consists of frame, crankshaft, pinion shaft, crosshead and extension rod.
· Continuous tooth herringbone gear.
· One-piece alloy steel crankshaft.
· Replaceable crosshead guides.
· Frame fabricated steel plate weldment provides the optimum rigidity, high strength and lightweight.
· Double sealing structure for extension rod provides good sealing.
· Power end utilizes the combination lubricating system of forced lubrication and splashing lubrication.

Frame
  Frame is made of steel plates by welding and stress relieving treated to provide the optimum rigidity and high strength. Strengthening structure of stiffening rib is used at crankshaft bearings. Necessary oil basin and lubricating system are provided in the frame for cooling and lubricating.

Crankshaft
   Crankshaft is made of casted alloy steel. Eccentric ring gear, connection rod and bearings are mounted on it. The eccentric ring gear is herringbone. When assembly, the herringbone bore and crankshaft are of interference fit and fastened with bolts and lock nuts. Big ends of connection rod are mounted on three eccentric straps of the crankshaft via single row cylindrical roller bearings. Small ends are mounted on crosshead pin via double row cylindrical roller bearing. Double row radial spherical roller bearings are mounted at either end of the crankshaft.

Pinion Shaft
  Pinion shaft is made of forged alloy steel, on which a herringbone gear with the medium-hard teeth surface is machined. For easy maintenance, single row radial cylindrical roller bearing with double ribbed outer ring is used. The pinion shaft ends are prolonged so that sheave or sprocket can be mounted on either end. 

Crosshead and Extension Rod
  Crosshead and crosshead guide are made of ASTM A48-83 meehanite featuring god abrasion resistance and long service life. Besides F-500 mud pump that is cylindrical structure, upper and lower guide structures are sued for other mud pumps, so that the concentricity can be adjusted by adding space under the lower guide. Flange-bolts with pinhole fit are used for connecting crosshead to extension rod. This rigid connection ensures the concentricity of extension rod and crosshead. Coupling is used for connecting extension rod to crosshead. Light coupling enables the extension rod and the crosshead to connect to each other with ease and reliableness.