Crane and its winch motor control system, float control valve for the system

Abstract

The invention discloses a crane, a winch motor control system thereof and a floating control valve used for the system. A pressure element used for winch motor floating and a reversing element are integrated in a valve body of the floating control valve, and a first oil port and a second oil port are formed outside the valve body. The first oil port and the second oil port are in butt joint with a first working oil port and a second working oil port of a winch motor respectively. When the winch motor is in a floating state, hydraulic oil in the motor directly enters the valve body through the second working oil port of the motor, the hydraulic oil passes through the pressure element, the reversing element and the first working oil port of the motor and returns to the inside of the winch motor again, pipeline connection is needless between the floating control valve and the winch motor, so that a channel between the two oil ports of the motor is shortened, oil circulating resistance is decreased, the volume between the pressure element and the motor is small, the requirements for the oil refilling speed and the oil refilling amount of the winch motor are lowered, the relative stability margin of the system is improved, the stabilization time of the system is shortened, and the winch motor which is provided with a balance valve in a master control oil line can have a floating function through the floating control valve.

Description

technical field [0001] The invention relates to the technical field of engineering machinery, in particular to a crane and its winch motor control system, and a floating control valve used in the system. Background technique [0002] In order to improve the bearing capacity of the boom of super-large-tonnage cranes, a super-lift mechanism came into being. Due to the inherent form of cooperation between the super-lift and the boom, the super-lift winch motor 3' generally needs to have a free floating function, that is to say, in the main When the arm is extended and the luffing is lowered, disconnect the connection between the motor and the oil pump, and connect the two oil ports of the motor so that the motor can rotate freely, so that the wire rope can be pulled out from the winch under the action of external force. [0003] When the hoist motor 3' is floating, due to the gravity of the hoist wire rope, the hoist motor 3' tends to rotate at an accelerated speed (that is, th...

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Problems solved by technology

[0007] At present, the floating control function of the super-lift hoist is mainly integrated in the main valve 1' of the super-lift. When floating control is required, the two oil ports of the motor must be communicated through a long pipeline, so that the two oil ports of the hoist motor 3' The oil storage volume between them is relatively large, and the oil compression volume is also relatively large. The requirements for oil replenishment speed and oil replenishment volume are relatively high, and stall phenomenon is prone to occur, which reduces the stability of the system.

[0008] Secondly, in order to prevent stalling, the pipeline between the two oil ports of the communication winch motor 3' is communicated with the damping in the super-lifting main valve 1' with the pipeline back pressure valve 4', and the adjustment of the back pressure valve 4' and the damping Very inconvenient

[0009] In addition, if the control form of the back pressure valve 4' is replaced by a balance valve, since the balance valve has a one-way locking function, it can only enter oil but not output oil in the absence of pilot pressure, that is, the motor can only start with a load. If it cannot rise and fall, this system cannot realize the floating function of the motor, so the use of pressure components in this hydraulic control system has great limitations.

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