Hydraulic pressure control valve

A hydraulic pressure control valve, comprising:

• a casing having six first oil grooves on its inner peripheral surface at specified intervals;
• a valve body rotatably disposed in said casing and having six second oil grooves on its outer peripheral surface at specified intervals;
• and
• two throttling units each of which consists of six throttles formed between said first oil groove and second oil groove and facing to each other in the radial direction;
• wherein respective said two throttling units are disposed between two different destinations, and a supply source of pressure oil and discharge port of pressure oil;
• respective two throttles facing to each other, in the radial direction in each of said two throttling units, one of which communicates with a discharge port of pressure oil and the other of which communicates with a supply source of pressure oil, are ones whose throttle areas do not substantially change until the relative angular displacement between said casing and said valve body reaches a predetermined magnitude;
• and
• the respective rest four throttles facing to each other in the radial direction among respective six throttles constructing said two throttling units are ones whose throttle areas decrease gradually in relation to the increase of the relative angular displacement.

A hydraulic pressure control valve comprising:

• a casing having six first oil grooves disposed on its inner peripheral surface;
• a valve body rotatably disposed in said casing and having six second oil grooves disposed on its outer peripheral surface;
• a first throttling unit having three radially facing pairs of throttles formed between said first and second oil grooves;
• a second throttling unit having three radially facing pairs of throttles formed between said first and second oil grooves;
• wherein, upon rotation of said casing relative to said valve body in a first direction, said radially facing pairs of throttles in said first throttle unit increase in throttle area and said radially facing pairs of throttles in said second throttle unit decrease in throttle area;
• wherein, upon rotation of said casing relative to said valve body in a second direction, said radially facing pairs of throttles in said first throttle unit decrease in throttle area and said radially facing pairs of throttles in said second throttle unit increase in throttle area;
• wherein said first and second throttle units are disposed between and in fluid communication with a source of pressure oil and a discharge port;
• wherein said first and second throttle units are in fluid communication with first and second chambers of a hydraulic cylinder so that:
• when said casing rotates relative to said valve body in said first direction, said first chamber is in fluid communication with said source of pressure oil and said second chamber is in fluid communication with said discharge port;
• and
• when said casing rotates relative to said valve body in said second direction, said first chamber is in fluid communication with said discharge port and said second chamber is in fluid communication with said source of pressure oil;
• wherein a selected radially facing pair of throttles in said first throttle unit have throttle areas which do not substantially change until said casing rotates relative to said valve body in said second direction by a predetermined amount;
• wherein one of said throttles in said selected radially facing pair in said first throttle unit fluidly communicates with said source of pressure oil and the other of said throttles in said selected radially facing pair in said first throttle unit fluidly communicates with said discharge port;
• wherein a selected radially facing pair of throttles in said second throttle unit have throttle areas which do not substantially change until said casing rotates relative to said valve body in said first direction by a predetermined amount;
• and
• wherein one of said throttles in said selected radially facing pair in said second throttle unit fluidly communicates with said source of pressure oil and the other of said throttles in said selected radially facing pair in said second throttles unit fluidly communicates with said discharge port.