REDUCING DIG FORCE IN HYDRAULIC IMPLEMENTS

摘要

In order to avoid cavitation in a boom cylinder (108) head end (152) at the beginning of a dig cycle, fluid from an alternate source (148, 188) is supplied to the head end (152) before or in addition to fluid supplied by the main boom-up hydraulic circuit (134, 156). In one embodiment, an electronic hydraulic valve (184, 202), related sensors (274), and control system (190) determines the beginning of a dig operation and uses fluid at an intermediate pressure to rapidly provide fluid to a boom (108) head end (152) cylinder to prevent voiding or cavitation before fluid under high pressure from the main pump (132) can be brought to the cylinder (108). An on/off fluid switch (184, 202) is activated early in a dig operation to address low pressure at the boom cylinder head end (152) and provide an alternate path for fluid into the cylinder (108) in reaction to the boom (106) being lifted by a motion of the stick (110) and bucket (114) in contact with the work surface (104).