| 摘要 |
A constant pressure valve includes a lock rod, a valve sleeve, a sliding shaft, a biasing unit, and a solenoid unit. The lock rod is formed with a first through hole. The valve sleeve is inserted fixedly into the lock rod, and includes an outer sleeve surface having a shrunk surface portion cooperating with the lock rod to define an annular space in fluid communication with the first through hole. The sliding shaft is movable in the valve sleeve to contact the lock rod, and includes a large-diameter section and a small-diameter section. The constant pressure valve is adapted to maintain a hydraulic device at a preset pressure. The less a difference between the diameters of the large-diameter section and the small-diameter section is, the more the preset pressure can be. |
| 主权项 |
1. A constant pressure valve adapted for maintain a hydraulic device at a preset pressure, said constant pressure valve comprising:
a lock rod including an inner hole centered at an axis, an inner rod surface defining said inner hole, an outer rod surface disposed around said axis, and a first through hole extending through said inner and outer rod surfaces; a valve sleeve fixed in said inner hole in said lock rod and extending along said axis, said valve sleeve including an axial hole centered at said axis, an inner sleeve surface defining said axial hole, an outer sleeve surface disposed around said axis and having a shrunk surface portion that cooperates with said inner rod surface of said lock rod to define an annular space therebetween, a second through hole extending through said inner and outer sleeve surfaces and disposed outwardly of said lock rod, and third and fourth through holes extending through said shrunk surface portion of said outer sleeve surface and said inner sleeve surface, said annular space being in fluid communication with said first through hole in said lock rod; a sliding shaft disposed movably within said axial hole in said valve sleeve and movable along said axis to contact said lock rod, said sliding rod including a first receiving chamber centered at said axis, an inner shaft surface defining said first receiving chamber, an outer shaft surface disposed around said axis, a closed end, an open end opposite to said closed end, an end wall disposed at said closed end, fifth and sixth through holes extending through said inner and outer shaft surfaces and disposed between said second and third through hole, and a seventh through hole extending through said end wall and in fluid communication with said first receiving chamber and said inner hole in said lock rod, said outer shaft surface having a large-diameter section distal from said end wall, and a small-diameter section proximate to said end wall, a portion of said outer shaft surface disposed between said large-diameter section and said small-diameter section cooperating with said inner sleeve surface to define a zero pressure space, said end wall cooperating with said inner sleeve surface and an end of said lock rod to define a hydraulic action space thereamong; a biasing unit disposed between said valve sleeve and said sliding shaft for biasing said sliding rod toward said lock rod; and a solenoid unit including a fixed iron cylinder mounted to said lock rod and extending along said axis, a second receiving chamber defined by said fixed iron cylinder, a movable iron rod movable within said second receiving chamber along said axis, and a coil member disposed around said fixed iron cylinder, said movable iron rod including a pushing rod section movable to push and move said sliding rod, said second receiving chamber being in fluid communication with said first receiving chamber in said sliding rod. |
