JP4064494B2 - Metering valve device - Google Patents

Description

【００１６】
【発明の効果】
上記を参照すると、本発明の主題の構成は、油圧シリンダの作動室内への流体の流量または作動室からの流体の流量を制御するために４つの独立に作動させることのできるスプール弁を用いた制御弁を提供していることが容易に明らかとなる。スプール弁の各々を独立に作動可能とすることにより、ポンプからシリンダへの流体の流量およびシリンダからタンクへの流体の流量を正確に制御することが可能となり、油圧シリンダに与えられる種々の作動状態を達成することが可能となる。更に、このスプール弁の組合せは、油圧シリンダのヘッド側作動室およびロッド側作動室へ流入、流出する流体を異なる流量にて容易に制御することを可能とする。
【図面の簡単な説明】
【図１】 本発明を説明するための参考実施形態の概略線図である。
【図２】 図１の矢視線２−２に断面図である。
【図３】 本発明の実施形態の概略線図である。
【符号の説明】
１０…計量弁装置
１１…入口ポート
１３…出口ポート
１６…制御ポート
１７…制御ポート
２２ａ…スプール弁
２２ｂ…スプール弁
２２ｃ…スプール弁
２２ｄ…スプール弁
２６…スプール
３４…ソレノイド弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control valve, and more particularly to a metering valve device having four independently operated electrohydraulic displacement control type spool valves.
[0002]
[Prior art]
A three-position four-way control valve that is typically used to control hydraulic motors that operate in both forward and reverse directions has a single spool to control the flow from pump to cylinder and from cylinder to tank. is doing. A problem with this type of hydraulic circuit is that a single spool of directional control valve is designed so that the timing of the metering slot optimizes flow control from the pump to the cylinder. Therefore, this spool is generally insufficient to meter the flow rate from the cylinder to the tank when the cylinder is being assisted.
[0003]
This problem has been somewhat solved by US Pat. No. 5,138,838. In the present invention, each of the pair of electrohydraulic control valves is configured to control the flow rate to one port and the flow rate from the other port of a single hydraulic cylinder operating in both forward and reverse directions.
[0004]
[Problems to be solved by the invention]
Of the four independently operated poppet valves, the pair of poppet valves controls the flow rate from the pump that flows into the working chamber to the cylinder, and the other pair of poppet valves flows from the working chamber to the tank. There is also a configuration in which the flow rate is controlled. This poppet valve configuration, however, requires a pair of load check valves disposed between the pump to cylinder poppet and the working chamber, which limits the number of possible operating modes. End up. Furthermore, since there are operating conditions where the metering characteristics for the flow rate of the poppet valve are very poor, the poppet valve is usually unsuitable for predictive control of the flow rate.
This invention makes it a technical subject to solve the problem of the said prior art.
[0005]
[Means for Solving the Problems]
According to one aspect of the present invention, the metering valve device is disposed between the inlet port, the outlet port, the pair of control ports, and the inlet port and the control port, and can be operated independently. First and second electrohydraulic displacement control type spool valves, and third and fourth electrohydraulic displacement control type spool valves which are disposed between the outlet port and the control port and can be operated independently. It has.
[0006]
According to another aspect of the invention, first and second electrohydraulic displacement control spool valves disposed between the inlet port and the pair of control ports and independently operable, and the outlet port In a method of operating a metering valve device comprising a third and a fourth electrohydraulic displacement control type spool valve disposed between the pair of control ports and independently operable, the third and the second Actuating both of the four spool valves to communicate the control port to the outlet port, and actuating both the first and second spool valves to communicate the control port to the inlet port. .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
First, referring to FIGS. 1 and 2, a reference embodiment that is not used to configure the present invention but is necessary for understanding the present invention will be described.
1 and 2, an independent metering valve 10 includes an inlet port 11 connected to a supply pump 12, an outlet port 13 connected to a tank 14, a head side working chamber 18 of a hydraulic actuator 21, and a rod side. A pair of control ports 16 and 17 connected to the working chamber 19 are provided. The metering valve 10 includes a pair of electrohydraulic actuation type displacement control type metering spool valves 22a and 22b. The spool valves 22 a and 22 b are disposed between the inlet port 11 and the control ports 16 and 17. The metering valve 10 further includes another pair of electrohydraulic operation type displacement control type metering spool valves 22c and 22d. The spool valves 22 c and 22 d are disposed between the control ports 16 and 17 and the outlet port 13. The spool valves 22a and 22b control the flow rate from the pump flowing into the working chamber to the cylinder, and the spool valves 22c and 22d control the flow rate from the cylinder flowing out from the working chamber to the tank.
[0008]
Since each of the spool valves 22a, 22b, 22c, and 22d is substantially the same valve, only the spool valve 22a will be described. In the drawing, the components of each of the four valves are indicated by the same reference numerals with the suffix a, b, c or d. The spool valve includes a pilot operated spool 26a having both ends 27a, 28a. A pressurized pilot fluid source 29 such as a pilot pump 31 is always in communication with one end 27a. A solenoid operated displacement control type pilot valve 34a is connected to the supply passage 32, the discharge passage 33 and the pilot passage 36a. The pilot passage 36a is connected to the other end 28a of the spool 26a and both ends of the pilot valve 34a. A feedback spring 37a is disposed between the spool 26a and the pilot valve 34a. In a normal state, the pilot valve is biased to a neutral position or a rest position shown in the figure, and the supply line is connected to the pilot passage. . A solenoid 38a is disposed on the opposite side of the feedback spring in the pilot valve. The spool valve is shown in the closed position when the solenoid valve is in the rest position.
[0009]
By sending an electric signal to the solenoid 38a, the displacement of the spool 26a is started, and a control force proportional to the electric signal energizes the pilot valve 34a. Due to this control force, the pilot valve is displaced toward the spool 26a against the urging force of the feedback spring 37a, and first the communication between the supply passage 32 and the pilot passage 36a is cut off, and then the pilot passage 36a The discharge passage 33 communicates with the pressure at the end portion 28a of the spool 26a. As a result, the pressure at the end portion 28a decreases, and the spool 26a moves toward the pilot valve 34a to the open position by the force of the pressurized working fluid acting on the end portion 27a. The control port 16 communicates. This is called a pump-cylinder communication state. As the spool 26a moves toward the pilot valve 34a, the feedback spring 37a that urges the pilot valve is compressed and counters the control force of the solenoid 38a. This movement continues until the feedback force acting on the pilot valve and the control force are balanced.
[0010]
Exciting the solenoid 38b of the spool valve 22b brings the pump-cylinder communication state between the inlet port 11 and the control port 17. By exciting the solenoids 38c and 38d, the control ports 16 and 17 and the outlet port 13 communicate with each other and a cylinder-tank communication state is established.
[0011]
A pressure relief valve 39 and a make-up valve 41 are disposed between the control ports 16 and 17 and the outlet port 13 in parallel with the flow of working fluid across the spool valves 22c and 22d.
[0012]
FIG. 3 illustrates an embodiment of the present invention . In this embodiment, when solenoid valve 34c is demagnetized, spool valve 22c is biased to the open position, relief valve 39 and make-up valve 41 associated with spool valve 22c are removed, and other independent An electro-hydraulic displacement control type spool valve 22 e that operates in this manner is disposed between the head side working chamber 18 to which the load of the actuator 21 is applied and the control port 16. A relief valve 46 and a make-up valve 47 are disposed between the head side working chamber 18 and the control port.
A relief valve 30 is disposed in the supply line 32 to maintain the supply line pressure at a substantially constant pressure level.
[0013]
The force acting on the hydraulic cylinder is either a resisting force, an assisting force or an excessive force. The resisting force is defined as a force that resists cylinder extension when the cylinder extends and a force that resists cylinder contraction when the cylinder contracts. The assisting force or excessive force is defined as the force assisting cylinder extension when the cylinder extends and the force assisting cylinder contraction when the cylinder contracts. An example of the resistance force is when the cylinder lifts the load, and an example of the assisting force is when the cylinder lowers the load. Further, when the spool valve that controls the flow rate from the cylinder to the tank is opened and the load is dropped so that the load is substantially free-falling, an excessive force state occurs.
[0014]
The flow from the pump to the cylinder and from the cylinder to the tank can be individually controlled by the metering valve device of the present subject matter, and precise control of the hydraulic cylinder is achieved in virtually all hydraulic cylinder operating conditions. Is possible. In particular, precise control when lifting the load is achieved by controlling the flow rate from the pump to the cylinder. Conversely, precise control when lowering the load is achieved by controlling the flow path from the cylinder to the tank. Finally, as shown in the table below, the cylinder is controlled in multiple situations by opening the three spool valves. The vertical column of the list shows whether the cylinder is expanding or contracting, whether the main force is resistance, subsidy or excessive force, and whether regeneration mode is selected or rapid drop is selected , Shows. The column next to the listing indicates which spool is open for weighing, fully open, or closed to achieve the desired result. Alternatively, a valve indicated as “open” also includes the case where it is only partially open to meter fluid flowing therethrough. This list best illustrates the operating characteristics of the embodiment of FIGS.
[0015]

[0016]
【The invention's effect】
Referring to the above, the configuration of the subject matter of the present invention used four independently actuable spool valves to control the flow rate of fluid into or from the working chamber of the hydraulic cylinder. It will be readily apparent that a control valve is provided. By enabling each of the spool valves to operate independently, it is possible to accurately control the flow rate of fluid from the pump to the cylinder and the flow rate of fluid from the cylinder to the tank. Can be achieved. Furthermore, this combination of spool valves makes it possible to easily control the fluid flowing into and out of the head side working chamber and the rod side working chamber of the hydraulic cylinder at different flow rates.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a reference embodiment for explaining the present invention .
FIG. 2 is a cross-sectional view taken along line 2-2 in FIG.
FIG. 3 is a schematic diagram of an embodiment of the present invention .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Metering valve apparatus 11 ... Inlet port 13 ... Outlet port 16 ... Control port 17 ... Control port 22a ... Spool valve 22b ... Spool valve 22c ... Spool valve 22d ... Spool valve 26 ... Spool 34 ... Solenoid valve

Claims (1)

In the metering valve device (10),
An inlet port (11);
An exit port (13);
A pair of control ports (16, 17);
Said inlet port and disposed between the control port, first and second electro-hydraulic displacement controlled spool valve capable of this actuating independently of the (22a, 22b),
Is disposed between the outlet port and the control port, third and fourth electro-hydraulic displacement controlled spool valve capable of this actuating independently of the (22a, 22b),
A hydraulic actuator having a pair of working chambers (18, 19) connected to the control port and including a spool valve (26e) disposed between one of the control ports and one of the working chambers. 21)
Each of the spool valves is a pilot operated spool (26) having first and second ends (27, 28), and a solenoid operated valve (34) connected to one end of the spool. A metering valve device.

Images