JPH1047305A - Measuring valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control the flow of a fluid in both normal and reverse directions between a pump and a cylinder by disposing a pair of independently actuated spool valves between an inlet port and control ports, and disposing another pair of independently actuated spool valves between an outlet port and the control ports. SOLUTION: A pair of electrohydraulically-actuated displacement control type measuring spool valves 22a, 22b that can be independently actuated are disposed between an inlet port 11 and control ports 16, 17. Another pair of electrohydraulically-actuated displacement control type measuring spool valves 22c, 22d that can be independently actuated are disposed between an outlet port 13 and the control ports 16, 17. The spool valves 22a, 22b control the flow of an operating fluid flowing into an operating chamber from a pump to a cylinder, and the spool valves 22c, 22d control the flow of the operating fluid flowing out of the operating chamber from the cylinder to the pump. The flow of the fluid from the pump to the cylinder and from the cylinder to the pump can thereby be controlled accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hydraulic control valve,
In particular, it relates to a metering valve device with four independently operating electro-hydraulic displacement control spool valves.

[0002]

2. Description of the Related Art A three-position, four-way control valve, typically used to control hydraulic motors operating in both forward and reverse directions, is a single valve for controlling the flow from the pump to the cylinder and from the cylinder to the tank. It has one spool.
A problem with this type of hydraulic circuit is that the single spool of the directional control valve is designed so that the timing of the metering slot optimizes the flow control from the pump to the cylinder. Thus, this spool is generally not sufficient to meter the flow from the cylinder to the tank when the cylinder is assisted.

[0003] This problem has been somewhat solved by US Patent 5,138,838. In this 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 that operates in both forward and reverse directions.

[0004]

Further, of the four independently operated poppet valves, one pair of poppet valves controls the flow rate from the pump flowing into the working chamber to the cylinder, and the other pair of poppet valves operates. There is also a configuration provided to control the flow rate from the cylinder flowing out of the working chamber to the tank. This poppet valve configuration, however, requires a pair of load check valves disposed between the pump to cylinder poppet and the working chamber, thereby limiting the number of possible operating modes. I will. In addition, poppet valves are usually unsuitable for predictive control of flow rates because of operating conditions where the metering characteristics with respect to the flow rate of the poppet valve are very poor. An object of the present invention is to solve the above-mentioned problems of the prior art.

[0005]

According to one aspect of the present invention, a metering valve device is disposed between an inlet port, an outlet port, a pair of control ports, and the inlet port and the control port. First and second electro-hydraulic displacement control spool valves which can be operated independently, and third and fourth electro-hydraulic displacement control spool valves which are disposed between the outlet port and the control port and which can be operated independently. An electrohydraulic displacement control type spool valve.

According to another feature of the invention, first and second electro-hydraulic displacement control spool valves are disposed between the inlet port and the pair of control ports and are independently operable; The method of operating a metering valve device comprising third and fourth electrohydraulic displacement control type spool valves disposed between an outlet port and the pair of control ports and capable of being operated independently. Actuating both the third and fourth spool valves to communicate said control port with said outlet port;
Actuating both the first and second spool valves to communicate the control port with the inlet port.

[0007]

1 and 2, an independent metering valve 10 comprises an inlet port 11 connected to a supply pump 12, an outlet port 13 connected to a tank 14, and a head of a hydraulic actuator 21. A pair of control ports 16, 1 connected to the side working chamber 18 and the rod side working chamber 19.
7 are provided. The metering valve 10 includes a pair of electro-hydraulic actuated displacement controlled metering spool valves 22a, 22b. The spool valves 22a and 22b are disposed between the inlet port 11 and the control ports 16 and 17. Measuring valve 10
Further includes another pair of electro-hydraulic actuated displacement controlled metering spool valves 22c, 22d. Spool valve 22
c and 22d are control ports 16 and 17 and outlet port 13
It is arranged between. The spool valves 22a, 22b
The flow rate from the pump flowing into the working chamber to the cylinder is controlled, and the spool valves 22c and 22d control the flow rate from the cylinder flowing out of the working chamber to the tank.

[0008] Spool valves 22a, 22b, 22c, 22
d are substantially the same valve, so the spool valve 22
Only a will be described. In the drawings, the components of each of the four valves are designated by the same reference numerals with subscripts a, b, c or d. The spool valve comprises 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 provided between the spool 26a and the pilot valve 34a. In a normal state, the pilot valve is biased to the illustrated neutral position or the rest position, and the supply line is connected to the pilot passage. .
In the pilot valve, a solenoid 38a is arranged on the opposite side of the feedback spring. The spool valve is shown in the closed position when the solenoid valve is in the rest position.

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 urges the pilot valve 34a.
By this control force, the pilot valve is displaced toward the spool 26a against the biasing force of the feedback spring 37a, and firstly, the communication between the supply passage 32 and the pilot passage 36a is cut off. The discharge passage 33 communicates with the end 28 of the spool 26a.
a pressure is released. As a result, the pressure at the end portion 28a decreases, and the spool 26a is moved by the force of the pressurized working fluid acting on the end portion 27a.
To the open position, and the inlet port 11 and the control port 16 communicate with each other. This is called a pump-cylinder communication state. As the spool 26a moves toward the pilot valve 34a, the feedback spring 37a that biases the pilot valve is compressed, and opposes the control force of the solenoid 38a. This movement continues until the feedback force and the control force acting on the pilot valve are balanced.

When the solenoid 38b of the spool valve 22b is excited, the pump-cylinder communication state is established between the inlet port 11 and the control port 17. Solenoid 38c,
By exciting 38d, the control ports 16, 17 and the outlet port 13 communicate to establish a cylinder-tank communication state.

The pressure relief valve 39 and the make-up valve 41
Is disposed between each of the control ports 16, 17 and the outlet port 13 in parallel with the flow of the working fluid across the spool valves 22c, 22d.

FIG. 3 illustrates an alternative embodiment of the present invention.
In this embodiment, when the solenoid valve 34c is demagnetized, the spool valve 22c is biased to the open position, and
The relief valve 39 and the make-up valve 41 related to the spool valve 22c are removed, and another independently operated electro-hydraulic displacement control type spool valve 22e is connected to the head side operating chamber 18 to which the load of the actuator 21 is applied. It is arranged between the control port 16. A relief valve 46 and a make-up valve 47 are provided between the head side working chamber 18 and the control port.
Are arranged. A relief valve 30 is provided in the supply line 32 to maintain the pressure in the supply line at a substantially constant pressure level.

[0013] The force acting on the hydraulic cylinder is a resisting force or an assisting or excessive force. The resisting force is defined as the force that resists the extension of the cylinder when the cylinder extends, and the force that resists the contraction of the cylinder when the cylinder contracts. The assisting or excessive force is defined as the force that assists the extension of the cylinder when the cylinder extends, and the force that assists the contraction of the cylinder when the cylinder contracts. One example of the resistance is when the cylinder lifts the load, and one example of the assisting force is when the cylinder lowers the load. In addition, excessive force is present when the load is reduced by opening the spool valve, which controls the flow from the cylinder to the tank, to allow the load to fall substantially free.

The flow from the pump to the cylinder and the flow from the cylinder to the tank can be individually controlled by the metering valve device of the subject of the invention, and the precise control of the hydraulic cylinders depends on the actuation of virtually all hydraulic cylinders. Attainable in the state. In particular, precise control when raising the load is achieved by controlling the flow 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, by opening the three spool valves, the cylinder is controlled in multiple situations, as shown in the table below. The vertical column in the list indicates whether the cylinder is extending or retracting, whether the primary force is resistive, assisting, or excessive, and whether regeneration mode or rapid drop is selected. Is shown. The columns next to the list indicate which spools are open for metering, fully open, or closed to achieve the desired result. Alternatively, a valve designated "open" also includes the case where the valve is only partially open for metering fluid flowing therethrough. This list is shown in Figure 1,
2 best illustrates the operating characteristics of the second embodiment.

─────────────────────────────────── Spool 26a 26b 26c 26d ス プ ー ル──────────────────────────── Neutral Closed Closed Closed Closed ───────────────── ────────────────── Extension Open Close Close Close Open Resistance Weighing Weighing ────────────────────────伸長 Extension Open Open Close Close Resistance Measurement Reproduction 再生伸長 Extension * Open Open * Open Close Resistance / Regeneration Meter-in Meter-out Pressure limit ───────────────────────────────伸長 Extension * Open Close * Open Open Resistance Meter-in Meter-out Pressure limit ─────────伸長 Extension Open Close Close Close Open Assist Weighing Weighing ─────────────────伸長 Extension Open Open Close Close Assistance Weighing Regeneration 再生─────────── Extension Open Open Close Close Assist伸長 Extension * Open Open * Open Close Assist / Regenerate Meter-in Meter-out Pressure limit ──────────────────────────────伸長 Extension * Open Close * Open Open Support Meter-in Meter-out Pressure limit ────────────────────────────────伸長 Extension Open Close Open Open Assist Measuring Weighing Rapid drop ────── ───────────────────────────── Contraction Closed Open Open Closed Resistance Weighing Weighing ───────────── ────────────────────── Contraction Close * Open Open * Open Resistance Meter-in Meter-out Pressure limit ─────────────── ──────────────────── Contraction Close Open Open Close Assist Measuring Weighing ──────────────────────収縮 Shrink Open Open Open Open Assist Measuring Metering Pump combination ───────────────────────────収縮 Shrink Open Open Open Open Assist Measuring Measuring High pressure pump combination ───────────────────────────────収縮 Shrink Closure Open Open Open Assist Weighing Weighing Rapid drop ──────── ────────────────────────── Float Close Close Open Open ─────────────────── ──────────────── Float Close * Open Open * Open Pressure limit Meter-in Meter-out ────────────────────── ───────────── * Adjust meter-in and meter-out to control pressure.

[0016]

With reference to the above, the configuration of the present subject matter can be operated independently of four to control the flow of fluid into or out of the working chamber of a hydraulic cylinder. It is readily apparent that a control valve using a spool valve is provided. By enabling each of the spool valves to operate independently, it is possible to accurately control the flow rate of the fluid from the pump to the cylinder and the flow rate of the fluid from the cylinder to the tank. Can be achieved. Further, the combination of the 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 first embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a schematic diagram of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Measuring valve device 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

 ──────────────────────────────────────────────────続 き Continued on front page (72) Jeffrey A. Inventor. Crosser United States, Illinois 60436, Shorewood, Oxford Lane 1113 (72) Inventor Thomas Jay. Hajek United States, Illinois 60441, Rockport, Box 36, Route 3

Claims (9)

[Claims] 1. A metering valve device (10), comprising an inlet port (11), an outlet port (13), a pair of control ports (16, 17), and disposed between the inlet port and the control port. A first and a second electro-hydraulic displacement control type spool valve (22a, 22b) that can be operated independently, and a second valve that is disposed between the outlet port and the control port and can be operated independently. A metering valve device comprising a third and a fourth electrohydraulic displacement control type spool valve (22a, 22b). 2. The metering valve device according to claim 1, wherein a relief valve (39) is arranged between one of the control ports and the outlet port. 3. The metering valve device according to claim 2, wherein a make-up (41) valve is disposed between one of the control ports and the outlet port. 4. A spool (26), each of said spool valves having first and second ends (27, 28), actuated by a pilot, and a solenoid actuated connected to one end of said spool. The metering valve device according to claim 1, comprising a type valve (34). 5. A feedback spring, wherein the solenoid-operated valve is disposed in line with the spool, and a feedback spring is disposed between the solenoid-operated valve and one end of the spool. 37. The metering valve device according to claim 4, comprising: (37) and means for biasing the spool toward the solenoid operated valve. 6. The metering valve device according to claim 4, wherein the metering valve device is combined with a hydraulic device having a pilot fluid source (29) constantly communicating with the other end of the spool. 7. A spool valve (26) having a pair of working chambers (18, 19) connected to the control port, and disposed between one of the control ports and one of the working chambers.
The metering valve device according to claim 4, comprising a hydraulic actuator (21) including e). 8. A first and a second electro-hydraulic displacement control spool valve (22a, 22a, 22) disposed between an inlet port (11) and a pair of control ports (16, 17), and independently operable. 22b) and third and fourth electro-hydraulic displacement control spool valves (2) disposed between the outlet port (13) and the pair of control ports and independently operable.
2a, 22b) comprising: operating both the third and fourth spool valves to communicate the control port with the outlet port; Actuating both of said spool valves to communicate said control port with said inlet port. 9. Metering valve device, ie a pump (12)
And a first control port (16) connected to an inlet port (11) connected to the hydraulic actuator and a first control port (16) connected to the head-side working chamber (18) of the hydraulic actuator. Electro-hydraulic displacement control type spool valve (22a)
And a second electro-hydraulic displacement, which is disposed between the inlet port and a second control port (17) connected to the rod-side working chamber (19) of the hydraulic actuator and can be operated independently. A control type spool valve (22b), and third and fourth electro-hydraulic displacement control type spool valves (22a) disposed between the outlet port (13) and the pair of control ports and capable of being operated independently. , 22b) comprising: operating the second spool valve to communicate the inlet port with the second control port; and operating the first spool valve. Connecting the first control port to the inlet port, operating the fourth spool valve to connect the outlet port to the control port, and operating the third spool valve. Connecting the control port to the outlet port by operating the metering valve device.