Dynamic load differential pressure protection balance valve controlled by three-level overflow valve

Abstract

Disclosed is a dynamic load differential pressure protection balance valve controlled by a three-level overflow valve. The dynamic load differential pressure protection balance valve controlled by the three-level overflow valve is composed of combination connection of a balance valve and a two-level protection overflow valve and a three-level overflow valve and a flow compensating one-way valve. The dynamic load differential pressure protection balance valve controlled by the three-level overflow valve is characterized in that a one-way valve core (6) is installed in a hole of a main valve core (5) in a sleeved mode. A right end spring cavity controlling the main valve core (5) is composed of a hydraulic control one-way valve whether is communicated with an A cavity or a B cavity. Several uniformly distributed axial direction small grooves are formed in a large cylinder at the right end of the main valve core (5). A holding cavity is communicated with the A cavity and is arranged between a main spring seat (10) and a valve body (3). A throttling opening of the two-level overflow valve is the combination that a fixing throttling opening and a variable throttling opening are in series connection. The three-level overflow valve and the flow compensating one-way valve are arranged on the left cavity of an overflow valve core (14). The control principle is that opening of the overflow valve core (14) is controlled by force produced by the fact that an adjusting pressure value of the three-level overflow valve multiplies a sectional area of the overflow valve core (14) and spring combination force. Closing of the overflow valve core (14) is completely controlled by spring force.

Description

1. Technical field: [0001] The invention relates to a dynamic load pressure difference protection balance valve controlled by a three-stage relief valve. This balance valve is especially suitable for concrete pump trucks with high precision, high pressure and high sealing life and reliability requirements, and also suitable for other various heavy machinery equipment. 2. Background technology: [0002] With the development of heavy machinery and equipment, some new requirements are put forward for the performance of the balance valve. For example, in order to protect the structural safety of the boom of the concrete pump truck under the There is a difference requirement of about 15% between the opening pressure and closing pressure of the flow valve. These are not available in domestic balance valves at present, which has led to the long-term dependence of such products on imported accessories and hindered the development of my country's main engine equipment. In addition,...

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Problems solved by technology

This design brings two problems in use: one is the opening pressure of 1.15 times the rated working pressure minus the very low oil return pressure, the pressure difference of the orifice is too large, and the small opening of the orifice will cause the oil cylinder The oil in the support cavity loses pressure rapidly, causing the boom to fall out of control

Although this method can alleviate the uncontrolled slide of the boom caused by the poor stability of the relief valve under certain conditions, it will bring huge pressure loss and energy consumption to the system under normal boom retraction conditions, causing the system to heat up. Damage to the sealing performance of the working medium and hydraulic system

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