Abstract: A hydraulic power steering apparatus 1 which is arranged so that a damper valve 10 is disposed in hydraulic oil circuits 8 and 9 for connecting an oil passage selector valve 11 in a gear box with right and left oil chambers of a power cylinder 6. The damper valve 10 comprises a spool valve. And a control oil chamber 21 of the spool valve 10 is connected with a hydraulic oil feed passage 18 for connecting a hydraulic pump 13 which is driven by an internal combustion engine so as to discharge hydraulic oil, with the oil passage selector valve 11. Its back pressure chamber 17 is connected with a hydraulic oil circulating passage 19 for connecting the oil passage selector valve 11 with a reservoir tank 12. Orifices 27 and 28 are provided in connecting oil passages 22 and 20, such that when discharge oil pressure of the hydraulic pump 13 rises, opening of the spool valve 10 increase.

Abstract: In a variable capacity type pump, in the inner diameter of a cam ring, an inner diameter of a portion forming a middle section between a suction section and a discharge section in a pump chamber is constituted by a negative slope curve in which an end portion of a suction port is set to be a start point, and a complete round curve and a negative slope curve are connected by a high-order curve.

Abstract: In a variable capacity type pump, in the inner diameter of a cam ring, an inner diameter of a portion forming a middle section between a suction section and a discharge section in a pump chamber is constituted by a negative slope curve in which an end portion of a suction port is set to be a start point, and a complete round curve and a negative slope curve are connected by a high-order curve.

Abstract: In a control valve of a power steering apparatus, mutually adjacent longitudinal grooves are formed at an inner surface of a sleeve, and each upper end of longitudinal grooves is arranged in a stagger layout, and each lower end thereof is arranged in a stagger layout.

Abstract: A hydraulic power steering apparatus 1 which is arranged so that a damper valve 10 is disposed in hydraulic oil circuits 8 and 9 for connecting an oil passage selector valve 11 in a gear box with right and left oil chambers of a power cylinder 6. The damper valve 10 comprises a spool valve. And a control oil chamber 21 of the spool valve 10 is connected with a hydraulic oil feed passage 18 for connecting a hydraulic pump 13 which is driven by an internal combustion engine so as to discharge hydraulic oil, with the oil passage selector valve 11. Its back pressure chamber 17 is connected with a hydraulic oil circulating passage 19 for connecting the oil passage selector valve 11 with a reservoir tank 12. Orifices 27 and 28 are provided in connecting oil passages 22 and 20, such that when discharge oil pressure of the hydraulic pump 13 rises, opening of the spool valve 10 increase.

Abstract: A damper valve for a hydraulic power steering device is disposed on a hydraulic oil circuit for connecting an oil passage changing-over valve in a gear box and left and right oil chambers of a power cylinder, and is provided with a partition plate member for partitioning the interior of a valve casing into two valve chambers. The partition plate member is formed at equal intervals along a peripheral direction with a plurality of through holes. A first valve spring plate for opening/closing every other one of the plurality of through holes is fixed to one wall face of the partition plate member facing a first valve chamber of the two valve chambers positioned on the oil passage changing-over valve side, while a second valve spring plate for opening/closing the other every other one of the plurality of through holes is fixed to the other wall face of the partition plate member facing a second valve chamber of the two valve chambers positioned on the power cylinder side.