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Hydraulic Valve Invention Patent No. CN 101737369 A

Posted: 2013-11-28 17:25:58  Hits: 1205
1. The invention belongs to hydraulic element, and relates to a multiple-way directional valve dedicated to forklift hydraulic system, in particular to a dynamic load sensing priority and shunt type multiple-way directional valve. The invention comprises a load sensing priority flow control valve and a group of multiple-way directional valves which are arranged on the valve body, the valve body is provided with a load sensing signal oil port capable of controlling the spool to move; the valve body is also provided with a flow divider, the oil inlet on the flow divider is connected with the pumping oil port on the valve body; the flow dividing oil port of the flow divider is connected with the braking oil port on the valve body; the main oil outlet of the flow divider is merged into the main oil outlet of the load sensing priority flow control valve and connected with the multiple-way directional valves. The invention is low in use cost, long in service life and high in running reliability, and the sub systems do not interfere with each other.

2. BACKGROUND

Multiple valve shunt forklift hydraulic control system is an important element, which is used to pump hydraulic fluid input assigned to the forklift main working system, hydraulic steering system and hydraulic brake system, it is usually by the installation In one of a diverter valve on the valve body and a set of forklift main work of the working oil supply system of multi-valve. Ordinary forklift hydraulic control system of the shunt-type multi-valve, its priority allocation of oil flow diversion is always allocated in accordance with pre-set value. On the system, even if its priority shunt circuit (usually hydraulic steering system) does not work, the system will still be priority in the allocation of the money supply of the oil flow shunt circuit, resulting in system energy losses and unnecessary system heating and temperature rise. In order to solve the above-mentioned amount, the Chinese Patent 200720131790.2 provides a dynamic load sensing priority multiple directional control valve, which uses the load-sensing priority flow control valve instead of the traditional one priority diverter valve, and the valve body Setting the load sensing signal port, and through the oil passage and the load-sensing priority flow control valve spool at one or both ends, so that the distribution of first shunt circuit oil flow can be different in accordance with the demand for priority oil, thereby reducing energy loss and lower the system temperature. In addition, the existing portion 5 to 10 tons forklift hydraulic system, to the hydraulic steering and braking operations in the United no interference, typically are used in the system are three oil pump. That is the main pump is one large and one small double-pump, which is only a small pump oil for hydraulic braking systems, the main pump in the large pump through the first shunt valve and auxiliary pump with a multi-way valve oil. Although such a system to solve the joint operation of steering and braking interference problems, but results from the actual use of the system point of view there are still some deficiencies as follows:

1)The configuration of the three pumps to increase the power loss of the hydraulic system, resulting in a high oil temperature in the hydraulic system;

2)Due to the current domestic double pump pressure rating only up to 20MPa, while the forklift hydraulic system working pressure is 20MPa. Under such pressure conditions in the conditions used for a long service life and reliability of the pump can not meet the requirements of users;

3)Due to double-pump hydraulic brake used a small pump displacement is small. Once in the whole process of using a slight decrease in the efficiency of its volume, the pump provides flow to the hydraulic brake system will have a significant impact. That directly affect the machine's braking effect. To change the user double-pump pump can only be replaced as a whole and can not be replaced individually small pump accessories, greatly improving its operation and maintenance costs.

3. SUMMARY OF THE INVENTION

1)The present invention technical problem to be solved is to provide a hydraulic system can be used in forklifts, and use of low cost, Long life, various sub-systems do not interfere with each other, high reliability and dynamic load sensing priority valve shunt.

2)The present invention dynamic load sensing priority and shunt valve includes a valve body mounted on a negative Load-sensing priority flow control valves and one group of the multiple of the working oil supply valve, said valve body is provided with a load sensing signal port, the port load sensing signal through the signal circuit and the load-sensing priority flow control valve connected to one or both ends of the spool valve can control the movement; said load-sensing priority flow control valve and valve inlet port on the main pump is connected; Load-sensing priority flow control valve and valve priority port on the steering oil port connection; load sensing priority flow control valve type main oil outlet valve connected to said multiplexer; wherein: the body is also provided with a diverter valve, diverter valve in the inlet and the valve on the secondary pump oil port connection; shunt valve shunt oil port and brake oil port on the valve body connection; shunt valve outlet port into the main load sensing priority flow control valve type main oil outlet, and multi-valve connection.

3)The load-sensing priority flow control valve includes a valve body is located in one of the priority valve; Priority middle center is provided with a valve closed at both ends of priority oil channels, both before and after first oil passage were set for use with side by side steering oil pump oil port and main port connection radial hole; priorities in the middle of the spool is provided with external multi-valve inlet connected ring groove, when the first setback when the spool is also the ring groove can be connected on the main pump valve port; signal port on the valve body and priorities spool rear oil chamber and through the first valve communicating signals on the oil passages and priorities spool front oil chamber connected, the signal oil channel parallel to a portion of said first oil passage side.

4)The technical program on abolition of the traditional structure of double-pump configuration, the traditional structure of the multi-channel Fazhu into the oily road in ordinary type diverter valve to the load sensing priority flow control valves, priority to meet the whole hydraulic steering system, excess oil supply system of work; oily in the auxiliary pump inlet flow path created a small shunt valve, hydraulic braking system for the machine to provide a stable source of oil hydraulic power, and its excess oil liquid supply working system. Thus, the whole hydraulic system only two single pump oil. And to ensure that the steering and braking are two separate oil supply source, and thus does not produce combined steering and braking operation when generating mutual interference. Such a system also has the following advantages unity:

--1 as configured with only two pumps, the hydraulic system power consumption can be reduced, which is a decline in oil hydraulic system provides a positive favorable conditions played a energy saving application effect.

--2 due to domestic pressure rating of a single pump 25MPa, while the forklift hydraulic system's normal working pressure of 20MPa.

Therefore, the system configuration two single pump in such conditions of use of its service life will be significantly improved.

--3 because the system eliminates the need for the original double-pump configuration switch to a single pump, the cost is greatly reduced, and the single pump
Through a small flow diverter valve oil to the hydraulic braking system on the avoided fuel pump volumetric efficiency of the hydraulic braking efficiency
Fruit implications. This also further improves the reliability of the system, reducing the cost of supporting the system.

4. Claim of Right

1)A dynamic load sensing priority and shunt valve, comprising a valve body mounted in (a) on a load-sensing priority flow control valve (2) and a group of the working oil supply multi- way valve (3), said valve body is provided with a load sensing signal port (Ls), the load sensing signal through the signal line to the oil port type load sensing priority flow control valve spool both ends of the connection and control the movement of the spool; said load-sensing priority flow control valve (2) in the inlet and the valve on the main pump port (P1) is connected; Load-sensing priority flow control valve The priority port and turn on the valve body ports (CF) connections; load sensing priority flow control valve type main oil outlet and multi-valve (3) connection; valve is also provided with a diverter valve (4), the shunt valve and valve inlet port on the auxiliary pump (P2) connector; diverter valve (4) with a shunt valve port (1) port on the brake fluid (BF) connection; shunt valve (4) into the outlet port of the main load-sensing priority flow control valve (2) of the main oil outlet, and multi-valve connection.
2) as claimed in claim 1, wherein the first and the dynamic load-sensing shunt valve, characterized in that: said load-sensing priority flow control valve (2) in the valve body comprises a first valve (21 ); first middle center of the spool is provided with a closed end first oil passage (22), first oil channel are provided both before and after the turning side to the port (CF) and the main pump port (PI) connected to the radial the hole (23), first valve (21) can be changed before and after the movement radial hole (23) and the steering port (CF) and the main pump port (PI) between the opening degree, thereby changing the steering oil port (CF) at a flow rate; first valve (21) is provided in the middle of the multiplexer outside the inlet valve (E) communicating the ring groove (24), when the first valve (21) when the setback ring groove (24) can be connected on the main pump valve port (PI); valve on the signal port (Ls) and the first valve (21) and the rear oil chamber communicating a signal through the first spool oil channel (25) and the first end of the oil chamber communicating valve, a part of the oil passage of the signal in parallel with said first oil passage (22) - side.

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