Pressurized fluid supply system

A direction control valve assembly with a pressure compensation valve, comprising:

• a valve block being formed with a spool bore, a check valve receptacle bore and a pressure reduction valve receptacle bore;
• a direction control valve constructed in such a manner that said valve block being further formed with an inlet port, first and second load pressure detecting ports, first and second actuator ports and first and second tank ports opening to said spool bore, and a main spool is disposed in said spool bore for selectively establishing and blocking communication between said ports;
• a check valve portion constructed in such a manner that said valve block is formed with a pump port opening to said check valve receptacle bore and a fluid passage communicating said check valve receptacle bore with said inlet port, and a spool is disposed within said check valve receptacle bore for establishing and blocking communication between said pump port and said fluid passage, and is stopped at the blocking position;
• and
• a pressure reduction valve portion constructed in such a manner that said valve block is formed with first and second ports opening to said pressure reduction valve receptacle bore, and a spool is disposed within said pressure reduction valve receptacle bore to define a first pressure chamber and a second pressure chamber, said first pressure chamber being communicated with said second load pressure detecting port, said second pressure chamber being communicated with said second port, and said spool is biased in one direction by means of a spring to bias the spool of said check valve portion toward a locking position;
• a pressure compensation valve is formed with said check valve portion and said pressure reduction valve portion;
• when said main spool is moved from a neutral position in one direction to place said main spool at a first pressurized fluid supply position, said inlet port being communicated with said first actuator port, and said second actuator port being communicated with the tank port, and said main spool is moved from a neutral position in the other direction to place at a second pressurized fluid supply position, said inlet port being communicated with a second actuator port, and said first actuator port being communicated with said tank port.

A direction control valve assembly comprising:

• a plurality of valve blocks, each valve block having an outer periphery and having first and second tank ports and a pump port being opened on the outer periphery at least at one end of the valve block mating with another valve block located adjacent thereto, each of said valve blocks being connected such that the first and second tank ports and the pump port opening at said one end of one valve block are placed in direct communication with the first and second tank ports and the pump port opening at a mating end of another valve block, respectively, and the pump port of any one of said valve blocks being connected to a main inlet port and the first and second tank ports of any one of said valve blocks being connected to a main tank port;
• a direction control valve provided in each of said valve blocks, each direction control valve comprising a main spool in the respective valve block for establishing and blocking communication between an inlet port, first and second actuator ports, first and second load pressure detecting ports and the first and second tank ports of the respective valve block;
• and
• a pressure compensation valve means provided in each of said valve blocks, each pressure compensation valve means being formed with a check valve portion and a pressure reduction valve portion, for supplying a pressurized fluid in the pump port to the inlet port of the respective valve block with pressure compensation based on a load pressure;
• and
• said pressure reduction valve portion having first and second ports such that the first and second ports of each of said valve blocks are in direct communication with the first and second ports of said adjacent valve block, respectively.