HYDRAULIC OIL CYLINDER, HYDRAULIC CUSHION SYSTEM, EXCAVATOR AND CONCRETE PUMP TRUCK

摘要

The present application discloses a hydraulic oil cylinder, of which a piston rod (3) is provided with at least two cushion collars (4, 11) which are axially slidable along the piston rod (3). Axial throttle oil channels (301a, 301b) are provided between the cushion collars (4, 11) and a piston (6). A first cushion collar (4) is provided with a sealing end face (401), and an end cover of a rod cavity (1) is provided with a sealing end face (101). The sealing end face (401) of the first cushion collar contacts with the sealing end face (101) of the end cover of the rod cavity to form a seal. Hydraulic oil within the rod cavity is discharged through one axial throttle oil channel (301a) to an oil passage B. A second cushion collar (11) is provided with a sealing end face (111), and an end cover of a rodless cavity (12) is provided with a sealing end face (121). The sealing end face (111) of the second cushion collar contacts with the sealing end face (121) of the end cover of the rodless cavity to form a seal. Hydraulic oil within the rodless cavity is discharged through another axial throttle oil channel (301b) to another oil passage A. The hydraulic oil cylinder can operate reliably and achieve a buffer function in a large load, high frequency operating condition, and thus has a longer operating life. And also, precision requirements for manufacturing the hydraulic oil cylinder are low, thereby facilitating production of the hydraulic oil cylinder. The present application also discloses a hydraulic cushion system, an excavator and a concrete pump truck which use the above hydraulic oil cylinder.