Patent ID: 8596407
Filing Date: 2013-12-03
Classification: B62D

Abstract:
1. An integral power steering apparatus comprising: a housing; an input shaft adapted to be connected with a steering wheel; a piston received in the housing and arranged to divide an inside cavity of the housing into a first pressure chamber and a second pressure chamber; a first translating mechanism provided between the input shaft and the piston and arranged to translate rotational motion of the input shaft into linear motion of the piston in an axial direction; a second translating mechanism including a rack provided in an outer circumference of the input shaft and a sector gear engaged with the rack, disposed in the second pressure chamber and arranged to translate linear motion of the rack into rotational motion; a control valve to supply an operating oil supplied from an external pressure source, selectively to the first pressure chamber or the second pressure chamber; a transmitting mechanism to transmit rotational motion of the sector gear to a steerable wheel; and first and second valves, the first valve being arranged to discharge a fluid pressure in the second pressure chamber toward the first pressure chamber when the piston moves to a first predetermined position in a first direction decreasing a volume of the first pressure chamber, and the second valve being arranged to discharge the fluid pressure in the first pressure chamber toward the second pressure chamber when the piston moves to a second predetermined position in a second direction decreasing a volume of the second pressure chamber; the first valve including, a first valve body provided on the first pressure chamber's side and formed with a first plunger receiving portion, a first plunger slidably received in the first plunger receiving portion of the first valve body, a first valve seat provided in the first valve body, arranged to form a part of a communication passage connecting the first pressure chamber and the second pressure chamber with each other and arranged to shut off the communication passage by abutment with the first plunger, and open the communication passage by separation of the first plunger from the first valve seat, a first stroke adjusting member which is provided in the first valve body and which includes a first spring seat, a first coil spring which is seated on the first spring seat and which is arranged to urge the first plunger toward the first valve seat, and a first spring pin which includes a first end portion press fit in the first plunger and a second end portion adapted to abut on the piston and which is arranged to separate the first plunger from the first valve seat by moving together with the first plunger by being pushed by the piston, and thereby to connect the first and second pressure chambers, the first stroke adjusting member being arranged to lie at a first position with respect to the first valve body at a time of adjustment of a press-fit position of the first spring pin with respect to the first plunger, and to limit movement of the first plunger by abutting on the first plunger, the first stroke adjusting member being arranged to be held at a second position separated from the first plunger after a press-fit position adjustment of the first spring pin, the second valve includes, a second valve body provided on the second pressure chamber's side and formed with a second plunger receiving portion, a second plunger slidably received in the second plunger receiving portion of the second valve body, a second valve seat provided in the second valve body, arranged to form a part of the communication passage connecting the second pressure chamber and the first pressure chamber with each other and arranged to shut off the communication passage by abutment with the second plunger, and open the communication passage by separation of the second plunger from the second valve seat, a second stroke adjusting member which is provided in the second valve body and which includes a second spring seat, a second coil spring which is seated on the second spring seat and which is arranged to urge the second plunger toward the second valve seat, and a second spring pin which includes a first end portion press fit in the second plunger and a second end portion adapted to abut on one of the piston and the sector gear and which is arranged to separate the second plunger from the second valve seat by moving together with the second plunger by being pushed by the piston or the sector gear, and thereby to connect the first and second pressure chambers, the second stroke adjusting member being arranged to lie at a third position with respect to the second valve body at a time of adjustment of a press-fit position of the second spring pin with respect to the second plunger, and to limit movement of the second plunger by abutting with the second plunger, the second stroke adjusting member being arranged to lie at a fourth position separated from the second plunger after a press-fit position adjustment of the second spring pin.