Hydraulic control apparatus

摘要

A hydraulic control apparatus is provided to prevent failure that can occur due to hunting, to elevate performance of a hydraulic control valve, and to improve operation efficiency by effectively conducting bleed off. The hydraulic control apparatus can include a first change over valve group that can include a change over valve connected with a first delivery line associated with the variable capacity pump, and arranged to have load sensing function. A second change over valve group can also be provided, and can include at least one change over valve connected with a second delivery line associated with the variable capacity pump. An open and close motion valve and a compensation valve can be configured to constitute a pressure compensation flow control means connected through the second delivery line and the second change over valve group.