Hydraulic pressure control valve

Claim 2

A hydraulic pressure control valve as set forth in Claim 1, 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.

Claim 3

A hydraulic pressure control valve as set forth in Claim 2, wherein said two destinations are two oil chambers of a hydraulic cylinder for assisting steering of a hydraulic power steering mechanism.

Claim 4

A hydraulic pressure control valve as set forth in Claim 1, wherein said respective two throttles have respectively a first notch on a first corner formed between the inner peripheral surface of said casing and the side wall of said first oil groove, said first notch being provided with a first portion which crosses said side wall at substantially right angle and is substantially parallel to said inner peripheral surface and with a second portion which crosses said first portion and the inner peripheral surface of said casing at substantially right angle thereby to connect the both, and have respectively a second linear or a circular-like notch on a second corner formed between the outer peripheral surface of said valve body and the side wall of said second oil groove, said second notch being formed by chamfering said second corner at a predetermined angle.

Claim 5

A hydraulic pressure control valve, comprising: a cylindrical 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; respective two throttles facing to each other, in the radial direction among respective six throttles constructing said two throttling units 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 among respective throttles constructing said two throttling units are ones whose throttle areas decrease gradually in relation to the increase of the relative angular displacement.

Claim 6

A hydraulic pressure control valve as set forth in Claim 5, wherein said respective two throttles have a first notch on the corner formed between the inner peripheral surface of said casing and the side wall of said first oil groove, said first notch being provided with a first portion which crosses said side wall at substantially right angle and is substantially parallel to said inner peripheral surface and with a second portion which crosses said first portion and the inner peripheral surface at substantially right angle thereby to connect the both, and has a second linear or circular-like notch on a corner formed between the outer peripheral surface of said valve body and the side wall of said second oil groove, said second notch being formed by chamfering said corner at a predetermined angle, and said respective rest four throttles have respectively a third linear or circular-like notch on a third corner formed between the outer peripheral surface of said valve body and the side wall of said second oil groove, said third notch being formed by chamfering said third corner at a predetermined angle

Claim 7

A hydraulic pressure control valve as set forth in Claim 6, wherein the length in the peripheral direction of said third notch is substantially same as summation of that of said first notch and that of said second notch.