Luffing jib maintaining valve for hydraulic shovel

Abstract

The invention relates to a movable arm maintaining valve used for hydraulic excavators, which is installed between the bottom of a movable arm hydraulic cylinder and a movable arm control valve of a hydraulic excavator and mainly used for controlling the lifting, maintaining and descending of a movable arm. The movable arm maintaining valve comprises a valve block (1) opened therein with a first valve opening and a second valve opening and provided thereon with an overflow valve (44), wherein a piston (4), a valve stem (6), a left spring holder I (8), a spring I (9), a right spring holder (11) and a maintaining valve (14) are sequentially arranged inside the first valve opening from the left to the right, a core I (20) of the maintaining valve (14) is connected with the valve stem (6), the valve opening site where the valve stem (6) locates communicates with the overflow valve (44), a left spring holder II (29), a spring III (28), a right spring holder II (26) and a non-return valve (23) are sequentially arranged at the right side from the left to the right, the core II (25) of the non-return valve (23) are matched with the inner hole of the right spring holder II (26), and the left side of the second valve opening communicates with the rodless cavity of the movable arm hydraulic cylinder of the hydraulic excavator. The inventive movable arm maintaining valve can remarkably reduce the sinkage of the movable arm, so as to be safer and more reliable.

Description

technical field

[0001] The invention relates to a holding valve, which is installed between the bottom of the boom hydraulic cylinder and the boom control valve of a hydraulic excavator. It is mainly used to control the lifting, maintaining and lowering of the boom. Suitable for excavators of various tonnages. It belongs to the technical field of hydraulic control components. Background technique

[0002] In a conventional hydraulic excavator, the boom hydraulic cylinder is directly connected to the boom control valve, and the boom control valve is directly used to control the rise, fall and maintenance of the boom. After the hydraulic excavator lifts the bucket off the ground, the reversing valve of the boom or stick hydraulic cylinder may be temporarily returned to the neutral position due to various reasons, and the engine is in the idle state at this time. At this time, if the valve of the reversing valve If the gap between the core and the valve body is too large, th...

Images