JPS6316602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control device for a single-acting hydraulic cylinder.

A commonly used slide spool type directional control valve consists of a sleeve and a spool that have cylindrical surfaces that slide against each other. The spool moves linearly in the axial direction within a fixed hollow cylindrical sleeve to simultaneously open and close several ports provided in the sleeve, thereby controlling the flow direction. .

By the way, the performance of a directional control valve is determined by this closing performance and flow resistance. That is, the play between the sleeve and the land of the spool must be minimized to maintain oil tightness, and the flow path must also minimize flow resistance and reduce pressure loss. In order to satisfy these requirements, high rigidity and advanced processing technology (especially honing selective fitting for the sleeve and spool fitting) are required to cover the distortion caused by the complex and highly accurate cross section of the valve body. ) is required. Therefore, the current directional control valves are large in size and expensive considering their functions.

In view of the above-mentioned drawbacks, this invention solves the problem by dividing the relatively installed closing mechanisms found in conventional directional control valves, making each one independent, simplifying the cross section of the valve body, and reducing the pressure loss in the flow path. Furthermore, the mating length of the sleeve and spool is shortened.
It is designed to reduce the difficulty of machining, allow common use of unit parts, and improve productivity, and is miniaturized for multiple control.

The configuration of the present invention will be explained below with reference to the drawings.

First, the structure and operating state of the directional control valve used in this invention will be explained with reference to FIGS. 1 and 2.

Figure 1 shows a normally open 3-port, 2-position electromagnetically actuated, spring return type directional control valve NO. 1 is a sleeve with a hollow cylindrical surface, and 3, 4, and 5 are oil ports provided in sleeve 1. The first, second, and third ports 2, which are flow ports, are constituted by a passage 6 that serves as an oil passage and a land 6a that has approximately the same diameter as the hollow cylinder of the sleeve 1 and serves as an oil seal. spool,
8 is a spring for pressing the spool 2 against the normal seat 26, and 7 is a solenoid for electromagnetically operating the spool 2 in the axial direction. In the state shown in the drawing, the first, second, and third ports 3, 4, and 5 are in communication via a passage 6, and when the solenoid 7 is energized, the spool 2 is pulled against the spring 8 to the right in the drawing. port 3 is moved to land 6a.
is blocked by However, the second port 4 and the third port 5 are always in communication via a passage 6.
Then, when the current is cut off and the external force of drawing the solenoid 7 is removed, the spool 2 is pressed against the seat 26 by the elasticity of the spring 8 and returns to its original position, and the first port 3 immediately passes through the passage 6 to the second and second ports. It communicates with ports 4 and 5 of 3.

Figure 2 shows a normally closed 3-port, 2-position, electromagnetically actuated, spring return type directional control valve NC, in which 1 is a sleeve with a hollow cylindrical surface, and 3, 4, and 5 are oil valves provided in sleeve 1. The first, second, and third ports 2, which are flow ports, are formed by a passage 6 that serves as an oil passage and a land 6a that has approximately the same diameter as the hollow cylindrical surface of the sleeve 1 and serves as an oil seal. 8 is a spring for pressing the spool 2 against the normal seat 26, and 7 is a solenoid that electromagnetically operates the spool 2 in the axial direction. In the illustrated state, the first port 3 is blocked by the land 6a,
When the solenoid 7 is energized, the spool 2 is attracted and moved to the left in the figure against the spring 8, and the first port 3 passes through the passage 6 to the second and third ports.
It communicates with ports 4 and 5. However, the second port 4
and the third port 5 are always in communication via a passage 6. Then, when the current is cut off and the external pulling force of the solenoid 7 is removed, the spool 2 is pressed against the seat 26 by the elasticity of the spring 8 and returns to its original position, and the first port 3 is immediately blocked by the land 6a.

This invention uses the above-mentioned directional control valves NO and NC to construct an operating hydraulic piping.The construction and operation of the operating hydraulic piping, which is the gist of this invention, will be explained below.

The present invention uses a single-acting hydraulic cylinder (ram cylinder) in which a piston rod is moved in and out by the elasticity of a spring or the weight of a load as a hydraulic actuator.

In Fig. 3, 27 is a normally open directional control valve;
Reference numerals 28, 29, and 30 are single-acting hydraulic cylinders that use the elasticity of springs 31, 32, and 33 built into the piston front chambers 28', 29', and 30' to return the piston rods 28'', 29'', and 30'' to their original positions. 34, 35, and 36 are normally closed directional control valves, the directional control valve 34 controls the hydraulic cylinder 28, the directional control valve 35 controls the hydraulic cylinder 29, and the directional control valve 35 controls the hydraulic cylinder 29. 36 also operates the hydraulic cylinder 30. Also, the directional control valves 34, 35, 36 operate the hydraulic cylinders 28, 2.
9, 30 piston back chambers 28, 29, 30
are connected to each other by pipes 19, 18, and 17, respectively. 9 is an oil tank, 12 is a hydraulic pump for generating pressure oil in the hydraulic system, and the pressure oil generated here is passed through a pipe 11 and controlled to a specified pressure value through a relief valve 13 provided in the middle. As shown, the directional control valves 34, 35, 36, and 27 are connected by pipes 21, 20, and 22 to form operating hydraulic pipes, which supply the pressure oil to the hydraulic cylinders. SOL-1, SOL-2,
SOL-3, SOL-4 each direction control valve 27, 34,
Solenoids 35 and 36, A1 and B1 are push button switches of the hydraulic cylinder 28, A2 and B2 are push button switches of the hydraulic cylinder 29, A3 and B3 are push button switches of the hydraulic cylinder 30, and the push button switches A1,
A2 and A3 extend the piston rods 28'', 29'', 30'' of the hydraulic cylinders 28, 29, 30, and push button switches B1, B2, B3 extend the piston rods 28'', 28'' of the hydraulic cylinders 28, 29, 30.
9″ and 30″ are operated to retract. 24 is the power supply, 25
indicates the power switch. An electric circuit is formed by connecting the above-mentioned electronic components with electric wires indicated by dashed lines as shown in the figure.

The above is the hydraulic piping for operating the single-acting hydraulic cylinder, and its function will be explained next.

In order to operate the hydraulic cylinder 28 in the state shown in FIG. 3, the power switch 25 is first turned on.
Then, when push button switch A1 is turned ON, the current flows through the switch 25 and wiring 23 to the solenoid.
Energize SOL-1 and SOL-2, and solenoid SOL
-1 and SOL-2 are energized and energized, so that the respective spools are attracted against the spring, so that the direction control valves 27 and 34 are switched. Then, the pressure oil generated by the hydraulic pump 12 is transferred to the pipe 11, the direction control valve 27, the pipe 22, the direction control valve 36, the pipe 20, the direction control valve 35, the pipe 21, and the direction control valve 3.
4. It flows into the piston back chamber 28 of the hydraulic cylinder 28 through the piping 19, and acts to extend the piston rod 28'' to the right against the spring 31.
Next, when the push button switch A1 is turned OFF, the current is cut off and the excitation of the solenoids SOL-1 and SOL-2 is released, and the respective spools are automatically pushed back by the stored elasticity of the spring and the directional control valves 27, 3
4 is switched, and from then on, no pressure oil is sent to the hydraulic cylinder 28, the extension operation of the piston rod 28'' is stopped, and the position is maintained.

Next, to move the piston rod 28'' in and out, turn on the push button switch B1.Then, the current passes through the switch B1 and only flows to the solenoid SOL-2, and by energizing and energizing the solenoid SOL-2, the spool is Since it is attracted against the spring, the directional control valve 34 is switched.Then, the piston rod 28'' of the hydraulic cylinder 28 is pushed back to the left by the stored elasticity of the spring 31 built in the piston front chamber 28'. .
At this time, the oil in the piston back chamber 28 is transferred to the piping 19, the directional control valve 34, the piping 21, the directional control valve 35, the piping 20, the directional control valve 36, the piping 22, and the directional control valve 2.
7. The oil is returned to the oil tank 9 via the pipe 10. Next, when the push button switch B1 is turned OFF, the current is cut off and the solenoid SOL-2 is de-energized, the spool is automatically pushed back against the spring, the directional control valve 34 is switched, and the oil tank 9 is then turned off.
The oil does not flow back to the piston rod 28'', and the retracting operation of the piston rod 28'' is stopped and the position is maintained.The above is the series of operations of the hydraulic cylinder 28.

The above description has been made regarding the operation of the hydraulic cylinder 28, but if the hydraulic cylinders 29 and 30 are also operated in the same manner, it is possible to operate them. still,
In the electric circuit of this hydraulic piping for operation, push button switches B1, A1, B2, A2, B3, A3 are connected to electric wires 3
7, 38, 39, 40, and 41, so when push button switch B1 is turned on, the current from this point on is cut off, and push button switch A is turned on.
Even if 1, B1, A2, B2, and A3 are turned ON, the hydraulic cylinder 28 only moves in and out, and no other operations are performed. Also, the above explanation is about a system that is operated by installing three hydraulic cylinders, but the normally open directional control valve NO.
into one basic circuit, one single-acting hydraulic cylinder
By consecutively connecting a circuit consisting of one normally closed directional control valve NC and one normally closed directional control valve NC, it is possible to operate a large number of hydraulic cylinders in the same way.

As explained above, the present invention combines electromagnetically actuated, spring return type, 3-port, 2-position directional control valves into only two types: normally closed and normally open, and each receives an electrically controlled signal. This enables multi-directional, multi-position, and multi-series hydraulic control by dividing the relatively installed closing mechanisms found in conventional directional control valves and making them independent. Simplify, reduce pressure loss in the flow path, shorten the mating length of the sleeve and spool, reduce the difficulty of processing, share unit parts and improve productivity, and enable multiple control. It can be made smaller in size. Furthermore, the hydraulic pressure generating unit circuit and the actuator can be separated and installed at any location, reducing pressure loss in the pipeline and simplifying the piping. Specifically, in order to operate one single-acting hydraulic cylinder, one normally open 3-port, 2-position electromagnetically actuated, spring return type directional control valve and a normally-closed 3-port, 2-position directional control valve are required. It is sufficient to use one electromagnetically actuated, spring return type directional control valve, and for each additional single-acting hydraulic cylinder, one normally-closed directional control valve described above can be added, making it possible to create multiple series. The more you do it, the more benefits you get.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a normally open directional control valve according to the present invention, FIG. 2 is a cross-sectional view of a normally closed directional control valve according to the present invention, and FIG. 3 is a hydraulic control of a single-acting hydraulic cylinder according to the present invention. FIG. 2 is a symbolic diagram of an electric-hydraulic combination circuit showing an embodiment of the device. NO...Always open directional control valve, 1...Sleeve, 3, 4, 5...Port, 2...Spool, 8
... Spring, 26 ... Seat, 7 ... Solenoid, NC ... Normally closed directional control valve.

Claims (1)

[Claims] 1 3 ports in 2 positions, in the open position the 3 ports communicate with each other, in the closed position only the 1st port is closed and the 2nd and 3rd ports communicate with each other. One return type directional control valve is used, the first port of the directional control valve is connected to the oil tank, the second port is the connection port to the hydraulic control circuit of the single-acting hydraulic actuator, and the third port is connected to the oil tank. It is equipped with a hydraulic pressure generating unit circuit whose port is connected to a hydraulic pump, and a plurality of single-acting hydraulic actuators, and one normally-closed directional control valve of the above configuration is used for each single-acting hydraulic actuator. , the first port of the directional control valve is connected to the piston back chamber of the corresponding single-acting hydraulic actuator, and the second and third ports of the directional control valve corresponding to each hydraulic actuator are respectively connected in a skewered manner, The hydraulic control circuit of the hydraulic actuator connects the third port of the final stage directional control valve to the connection port of the hydraulic pressure generation unit circuit, and the two switches that energize and operate the directional control valve of each single-acting hydraulic actuator are connected to each other. A switch is provided for each single-acting hydraulic actuator, and when one switch is operated, the directional control valve of the hydraulic pressure generating unit circuit is energized at the same time, and when the other switch is operated, the direction of the single-acting hydraulic actuator is changed. 1. A hydraulic control device for a single-acting hydraulic cylinder, comprising an operating electric circuit that operates only the control valve and leaves the directional control valve of the hydraulic pressure generating circuit in an inoperable state.