| 摘要 |
In a hydraulic shock absorber 10, at least one of a first base piston 50 and a second base piston 60 is provided with a communication path 44 communicating an intermediate portion between a compression side damping valve 51 and a compression side check valve 52 which are provided in respective compression side flow paths 50A, 60B of the first and second base pistons 50, 60 with an oil reservoir chamber 32, and communicating an intermediate portion between an extension side damping valve 61 and an extension side check valve 62 which are provided in respective extension side flow paths 60A, 50B of the first and second base pistons 50, 60 with the oil reservoir chamber 32. |
| 主权项 |
1. A hydraulic shock absorber comprising:
an oil chamber of a cylinder provided in a damper case which is attached to one of a vehicle body side and an axle side; a piston rod attached to another of the vehicle body side and the axle side, the piston rod being inserted into the oil chamber; a piston provided in a leading end portion of the piston rod; the oil chamber of the cylinder being divided into a piston side oil chamber and a rod side oil chamber by the piston; an oil reservoir chamber compensating a volumetric capacity of the piston rod which goes to and out of the oil chamber of the cylinder, the oil reservoir chamber being communicated with the oil chamber of the cylinder; a damping force generating device provided between the piston side oil chamber and the rod side oil chamber of the cylinder, said damping force generating device having a compression side damping valve and an extension side damping valve; an outer flow path communicating between the piston side oil chamber and the rod side oil chamber, the outer flow path being provided around the oil chamber of the cylinder in the damper case; the damping force generating device being provided with at least one compression side flow path which circulates an oil in the piston side oil chamber of the cylinder toward the rod side oil chamber via the outer flow path of the cylinder in a compression side stroke, the compression side flow path being provided with the compression side damping valve in its upstream side and with a compression side check valve in its downstream side, and a compression intermediate portion between the compression side damping valve and the compression side check valve which are provided in the compression side flow path being communicated with the oil reservoir chamber; and the damping force generating device being provided with at least one extension side flow path which circulates an oil in the rod side oil chamber of the cylinder toward the piston side oil chamber via the outer flow path of the cylinder in an extension side stroke, the extension side flow path being provided with the extension side damping valve in its upstream side and with an extension side check valve in its downstream side, and an extension intermediate portion between the extension side damping valve and the extension side check valve which are provided in the extension side flow path being communicated with the oil reservoir chamber, said compression intermediate portion and said extension intermediate portion having at least a common portion, wherein the damping force generating device has first and second base pistons which are arranged at two positions aligned along an axial direction of the cylinder, the compression side damping valve and the extension side check valve are respectively provided in the compression side flow path and the extension side flow path which are provided in the first base piston, and the extension side damping valve and the compression side check valve are respectively provided in the extension side flow path and the compression side flow path which are provided in the second base piston, and at least one of the first base piston and the second base piston is provided with a communication path communicating the intermediate portion between the compression side damping valve and the compression side check valve which are provided in the respective compression side flow paths of the first and second base pistons with the oil reservoir chamber, and communicating the intermediate portion between the extension side damping valve and the extension side check valve which are provided in the respective extension side flow paths of the first and second base pistons with the oil reservoir chamber, the oil reservoir chamber is provided around the periphery of the oil chamber of the cylinder and the outer flow path in the damper case, the first and second base pistons are fixedly provided around a bolt, and the second base piston is immobilized to a bottom portion in one end side of the cylinder, wherein the extension side flow paths and the compression side flow paths extend through the first base piston and the second base piston in a longitudinal direction of the hydraulic shock absorber, and the communication path extends through the first base piston or the second base piston in a direction transverse to the longitudinal direction. |
