JPH0337645B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) This invention comprises a differential circuit that allows return oil from the rod side chamber to flow into the bottom side chamber when pressure oil is being supplied to the bottom side chamber of the cylinder. This invention relates to a control valve device.

(Prior Art) Fig. 3 shows a conventional device, in which a cover 2 and a subplate 3 can be attached to the upper and lower sides of a valve body 1, and a pair of valve holes 4 and 5 are formed in the valve body 1. A spool 6,
7 is provided.

The spools 6, 7 are hollow and have partition walls 8, 9 formed approximately in the center thereof, defining chambers 10, 11 and 12, 13 within the spools 6, 7.

In the upper chambers 10 and 12 are valve holes 4 and 5.
Support rods 14 and 15 hanging vertically from the upper end are exposed. These support rods 14 and 15 have flanges 1
One of the spring receivers 18 and 19 formed with 6 and 17 is slidably inserted, and the support rods 14 and 15 are
The other spring receivers 22, 23 are slidably inserted, and are prevented from being pulled out by flange-like stoppers 20, 21 at the lower ends.

And the spring receivers 18, 22 and 19, 23
Springs 24 and 25 are interposed between them, and the flanges 16 and 17 are hooked onto bent portions 26 and 27 at the upper ends of the spools 6 and 7, so that the spools 6 and 7 are normally maintained in the state shown in the figure. There is.

Valve hole 4 provided with spools 6 and 7 as described above,
A discharge passage 28 and a supply passage 29 are formed around the discharge passage 5 .

One main passage hole 30 is formed on the side of the chamber 11 below the one spool 6, and when the spool 6 is in the illustrated state, this main passage hole 30
0 is located approximately midway between the discharge flow path 28 and the supply flow path 29.

That is, when the spool 6 moves either up or down, the main passage hole 30 communicates with either the discharge channel 28 or the supply channel 29.

In addition, on the chamber 13 side below the other spool 7,
A main passage hole 31 and a sub-hole 32 are formed, and the upper main passage hole 31 is located between the discharge passage 28 and the supply passage 29 in the illustrated state, and the lower sub-hole 3
2 is located slightly below the supply channel 29. The main through hole 31 and the sub through hole 32 maintain the following relationship.

In other words, when the spool descends, the main through hole 3
1 communicates with the supply channel 29, and the main through hole 31
It maintains a position where it does not communicate with either the discharge channel 28 or the supply channel 29.

Orifices 33 and 34 are formed below the spools 6 and 7, and the other spool 7 is provided with a check valve 58.

The check valve 58 is in a relationship that allows only the flow from the orifice 34 to the chamber 13 side, and the chamber 1 is connected to the pressure receiving area a on the seat side.
The area b on the third side is made smaller.

The chamber 11 of the spools 6, 7 thus constructed,
13 are actuator channels 35 and 3 formed in the sub-plate 3 via the orifices 33 and 34.
It is connected to 6.

And the actuator flow path 3 leading to the chamber 11 side
5 is an actuator flow path 36 that communicates with the bottom side chamber 38 of the cylinder 37 and communicates with the chamber 13 side.
is communicated with the rod side chamber 39.

Pilot channels 40 and 41 are connected to the actuator channels 35 and 36, and these pilot channels 40 and 41 are connected to port 5 of the switching valve 52.
It is connected to 3,54.

Detection orifices 42 and 43 are provided in the flow paths of the pilot flow paths 40 and 41, respectively.
That is, the detection orifices 42, 43 are formed in auxiliary members 44, 45 fitted from the outside of the cover 2, and damper orifices 46, 47 are also formed in these auxiliary members 44, 45.
The insides of the auxiliary members 44, 45 are hollow portions 48, 49 between the portions in which these detection orifices 42, 43 and damper orifices 46, 47 are formed.

In this control valve device, the discharge passage 28 is communicated with the tank 5 and the port 55 of the switching valve 52, and the supply passage 29 is communicated with the pump 51 and the port 56 of the switching valve 52.

The switching valve 52 having the ports 53 to 56 formed therein as described above has a center-open configuration in which both pilot channels 40 and 41 are opened to the tank 50 in its neutral position.

Note that the reference numeral 57 in the figure is a flow control valve.

However, if the switching valve 52 is switched to the left position from the state shown, the pilot flow from the pump 51 will flow through the supply channel 29 and the port 5 of the switching valve 52.
6 and 53 to reach one pilot flow path 40.

The oil flowing into the pilot flow path 40 flows into the actuator flow path 35 through the detection orifice 42;
2, which causes a pressure drop in the form of a pressure difference before and after the flow rate. The pressure on the inflow side of the detection orifice 42 then flows into the chamber 10 above the spool 6 through the damper orifice 46.

At this time, the pressure on the chamber 11 side below the spool 6 becomes lower than the pressure in the chamber 10 by the amount of the pressure drop at the detection orifice 42, so the spool 6 moves down against the spring 24.

When the spool 6 is lowered, the main passage 30 communicates with the supply passage 29, and therefore the main flow from the pump 51 flows through the supply passage 29, the chamber 11, and the orifice 3.
3 and the actuator flow path 35 into the bottom side chamber 38 of the cylinder 37 .

As a result, the cylinder 37 receives a thrust in the extension direction, but the pressure generated in the rod side chamber at this time becomes greater than the pressure in the bottom side chamber due to the difference in pressure receiving areas on both sides of the piston. Therefore, no pilot flow from port 56 to port 54 occurs.

Conversely, the pilot flow, which is the return oil in the rod side chamber 39, first flows from the actuator flow path 36 to the pilot flow path 41, passes through the detection orifice 43, reaches the port 54 of the switching valve 52, and from there flows into the pilot flow path 40. merge with the side stream.

When the pilot flow from the rod side chamber 39 passes through the detection orifice 43 as described above, a pressure drop occurs in accordance with the flow rate, as described above.
Therefore, the chamber 13 side of the spool 7 has a higher pressure than the chamber 12 side, so the spool 7 has a higher pressure than the chamber 12 side.
5, and the sub-hole 32 is connected to the supply flow path 2.
Connect to 9. Then, the main flow of the rod side chamber 39 flows through the check valve 58 against the return spring 59.
is pushed open and reaches the bottom side chamber 38 through the auxiliary passage hole 32 and the supply channel 29, and the feeding speed of the piston of the cylinder 37 is increased.

On the other hand, when the switching valve 52 is switched from the left position in the figure to the neutral position, both pilot flow paths 40, 41
communicates with tank 50 via port 55, drain passage 60 and discharge passage 28, and its pilot flow is eliminated.

As mentioned above, the pilot flow disappears, so
The pressure in the lower chamber 11 of the spool 6 is lower than the pressure in the upper chamber 11.
The pressure becomes equal to that of , and the spring 24 returns to the neutral position shown in the figure, and the supply of oil to the cylinder 37 is cut off.

On the other hand, when the flow from the rod side chamber 39 disappears in the spool 7, the check valve 58 is activated by the return spring 59.
It closes upon receiving the supply pressure 29 due to the relationship of pressure receiving area a>b, and returns to the neutral position shown in the figure by the action of the spring 25.

On the other hand, if the switching valve is returned to the neutral position as described above and then switched to the right position in the drawing, the pump 5
The pilot flow from port 1 is from port 56, 54 →
The detection orifice 43 passes through the pilot flow path 41 and reaches the actuator flow path 36. At this time, a pressure difference is generated before and after the detection orifice 43, which is the same as described above, and this causes the spool 7 to descend.
The main through hole 31 is communicated with the supply channel 29 .

Therefore, the main flow from the pump 51 reaches the rod side chamber 39 of the cylinder 37 via the supply passage 29 → chamber 13 → orifice 34 → actuator passage 36.

The pilot flow on the return side of the bottom side chamber 38 flows from the pilot flow path 40 to the detection orifice 42.
→Ports 53, 55 of switching valve 52 →Discharge flow path 28
It returns to tank 50 through. At this time, a pressure difference is generated before and after the detection orifice 42, and as a result, the spool 6 rises in the same manner as described above, and the main through hole 3
0 is communicated with the discharge flow path 28. Therefore, the main flow on the return side of the bottom side chamber 38 is from the actuator passage 35 to the orifice 33 to the chamber 11 to the main passage hole 3.
0 → returns to the tank 50 through the discharge flow path 28.

Reference numerals 61 and 62 in the figure are pilot check valves, which are used to prevent the cylinder from moving inadvertently when an external force is applied to the cylinder.

(Problems to be Solved by the Present Invention) According to the above-mentioned device, during the extension operation of the actuator 37, the discharged oil is guided from the rod side chamber 39 to the bottom side chamber 38, so that the supply flow rate to the bottom side chamber 38 is large and the extension speed is increased. There are advantages to being able to do so.

However, this conventional device has a problem in that the thrust force is small because the pressure-receiving area is the cross-sectional area of the rod.

An object of the present invention is to provide a control valve device constituting a differential circuit that moves the cylinder quickly up to a certain position and applies a large thrust from the moving position where a load is applied.

(Means for Solving the Problems) In the present invention, a pair of spools, each having two chambers, are provided in the valve body, and the chamber on one side of one of the spools is connected to the valve body through an actuator flow path. A pair of pilot flows are connected to the bottom side chamber of the cylinder, and the chamber on one side of the other spool is connected to the rod side chamber of the cylinder via an actuator flow path different from the above, and communicated with the actuator flow path. the passages respectively communicate with the switching valves, and the pilot passages communicate with the chamber on the other side of each of the spools,
A detection orifice is provided in the flow process between the chamber on the other side and the actuator flow path, and each of the pair of spools is provided with a main through hole, which opens the chamber on the one side depending on the movement position. In a control valve device that is configured to communicate with or shut off either the discharge flow path leading to the tank or the supply flow path leading to the pump, the spool leading to the rod side always has a hole connected to the supply flow path in addition to the main passage. A auxiliary passage hole is provided inside the auxiliary passage hole, and a check valve is provided inside the auxiliary passage hole, which allows flow only from the actuator passage to the auxiliary passage hole, and forms a flow passage that is always in communication with the auxiliary passage hole. The pilot flow path leading to the tank is characterized by a control valve device constituting an operating circuit including a valve that connects the pilot flow path with the tank when the bottom reaches a set pressure in the Japanese-style chamber.

(Function) In the no-load or light-load state, this invention
While the extension speed of the actuator is increased like in the conventional device, in a high load state, the discharge flow from the rod side chamber is guided to the tank, and a large thrust is obtained by using the pressure receiving area of the actuator as the piston cross-sectional area.

(Embodiment of the present invention) To explain FIG. 1, the upper main passage hole 31 of the spool 7 is closed between the discharge passage 28 and the supply passage 29 in the neutral state shown in the figure, but when the spool 7 is lowered. When the spool 7 is raised, it communicates with the supply channel 29, and when the spool 7 rises, it communicates with the discharge channel 28.

On the other hand, the lower sub-hole 32 communicates with the supply channel 28 in the state shown above, and always communicates with the supply channel 28 even when the spool 7 moves up and down, although its opening area varies in size. We are in a relationship. The switching valve 52 has a port 53 communicating with the pilot passage 40, a port 54 communicating with the pilot passage 41, and a port 5 communicating with the discharge passage 28.
5. A port 56 communicating with the supply channel 29 is provided.

When the switching valve 52 is in the neutral state shown in the drawing, each of the ports 53, 54, 55, and 56 is in a blocked state. Further, when the switching valve 52 is in the left position in the drawing, the ports 53 and 56 communicate with each other, and the ports 53 and 56 communicate with each other.
4 and port 55 are in a blocked state.

Furthermore, when it is located on the right side in the drawing, port 53
and port 55, and port 54 and port 55 are in a communication relationship, respectively.

An electromagnetic switching valve 64 is provided in the middle of a passage connecting the pilot flow path 41 and the port 54,
The electromagnetic switching valve 64 is normally in a closed state, and when the pressure in the bottom side chamber 38 of the actuator 37 reaches a preset pressure, the electromagnetic switching valve 64 closes the pilot flow path 41 in conjunction with a pressure detector (not shown). It is configured to communicate with tank 67. Note that the other configurations are the same as the conventional device shown in FIG. Next, to explain the operating state of this embodiment,
First, when the switching valve 52 is in the neutral state shown in the drawing, both the pilot flow paths 40 and 41 are blocked, so the spools 6 and 7 are in the shown state without operating.

When the switching valve 52 is placed in the left position in the drawing, port 5
5 and port 54 remain closed, or port 56 and port 53 communicate with each other, so that the pressure in supply channel 29 is guided to pilot channel 40.

As a result, the front pressure of the detection orifice 42 is introduced into the upper chamber 10 of the spool 6, the rear pressure acts on the lower chamber 11, and the spool 6 is lowered due to the differential pressure before and after the detection orifice 42, and the main passage 30 communicates with the supply channel 29 . Therefore, the supply pressure from the pump 51 is introduced into the bottom side chamber 38 of the actuator 37 through the flow path 35, and the actuator 37 is operated to extend.

On the other hand, the spool 7 does not operate because there is no flow in the pilot flow path 41, and the pressure in the rod side chamber 39 is balanced with a pressure receiving area that is smaller than the bottom side chamber 38 by the cross-sectional area of the rod. The pressure difference acts on the pressure-receiving area (a-b) of the check valve 58 to open the check valve 58, and the rod side chamber 39 communicates with the supply passage through the sub-hole 32. Rod concubine 3
9 flows into the bottom side chamber 38;
The actuator 37 operates to extend with the cross-sectional view of the rod serving as a pressure-receiving area.

As a result, the flow rate supplied to the bottom side chamber 38 becomes greater than the discharge flow rate of the pump 51, and the cylinder expansion speed can be increased. In other words, even a pump with a small discharge amount can obtain a substantially high discharge flow rate.

During the above extension operation, a high load is applied to the rod,
When the pressure in the bottom side chamber 38 rises to a set pressure, the electromagnetic switching valve 57 is switched in conjunction with a pressure detector (not shown) to communicate the pilot passage 41 with the tank 67.
As a result, the pilot flow path 41 contains the rod side chamber 3.
9 to the tank 67, a pressure difference is generated before and after the detection orifice 43, and the front pressure acts on the lower chamber 13 of the spool 7, and the rear pressure acts on the upper chamber 12, causing the spool 7 to move upward. The main passage 31 communicates with the discharge passage 28 and the discharge flow of the rod side chamber 39 flows through the discharge passage 28 to the tank 50. For this reason, Rod concubine 3
9 is lower than the pressure in the supply channel 29, and the check valve 58 receives the reaction force of the spring 59 and the supply pressure of the pump 51 through the sub-hole 32 to the pressure receiving area (a-b) on the back of the check valve. The valve opens by acting on the valve.

Therefore, the flow from the rod side chamber 39 to the bottom side chamber 38 is blocked by the check valve 58, and the extension speed of the actuator 37 becomes slower, but the pressure receiving area of the actuator 37 becomes the piston cross-sectional area, and the thrust increases.

Therefore, the extension speed can be increased in a no-load or light-load state, and the thrust can be increased in a high-load state, thereby increasing mechanical efficiency.

Next, when the switching valve 52 is moved to the right position in the drawing, the ports 56 and 54 and the ports 55 and 53 communicate with each other, the pilot flow path 40 connects to the tank 50 via the discharge flow path 28, and the pilot flow path 41 connects to the supply flow path. 29 to the pump 51, respectively. As a result, the spool 7 is lowered by the front side pressure of the detection orifice 3 acting on the upper chamber 12 and the rear side pressure acting on the lower chamber 13, and the main passage hole 31
The supply pressure from the pump 51 is communicated with the flow path 36.
is introduced into the rod chamber 39 of the actuator 37 via the rod chamber 39 of the actuator 37.

On the other hand, the front pressure of the detection orifice 42 acts on the chamber 11 and the rear pressure acts on the upper chamber 10 on the spool 6, causing the spool 6 to rise and the main passage hole 30 to communicate with the discharge passage 28. The bottom side chamber 38 is connected to the tank 5
Contact 0. For this reason, the actuator 37
is activated by contraction.

Although the back side of the check valve 58 is connected to the supply channel 29 through the sub-hole 32, the valve does not open due to the supply pressure acting on the spring 59 and the pressure-receiving area (a-b). In the second embodiment shown in FIG.
A relief valve 66 as a pressure detection valve is connected to the side.

The check valve 65 allows only the flow from the port 54 of the switching valve 52 to the pilot channel 41, and blocks the flow from the pilot channel 41 to the port 54 of the switching valve 52.

Further, the relief valve 66 is connected to the pilot flow path 4.
When the pressure on the 0 side becomes equal to or higher than the set pressure, the valve opens and the oil from the pilot flow path 41 is discharged to the discharge flow path 2.
I'm trying to stream it to 8.

The rest of the structure is completely the same as that of the first embodiment.

Therefore, when pressure oil from the pump 51 is being supplied to the bottom side chamber 38 and the pressure in the bottom side chamber 38 is lower than the set pressure of the relief valve 66, the rod side chamber 39 The return oil joins the supply flow path 29.

When the pressure in the bottom side chamber becomes equal to or higher than the set pressure, the relief valve 66 is opened, a flow is generated in the pilot passage 41, and the spool 7 is raised due to the pressure difference before and after the detection orifice 43.

When the spool 7 rises in this way, the rod side chamber 39 reaches the tank pressure, which is the same as in the first embodiment.

In this second embodiment, since the check valve 65 is provided as described above, the ports 53 and 64 of the switching valve 52 are configured to communicate with the discharge passage 28 when the switching valve 52 is in the neutral position. .

(Effects) According to the present invention, the elongation speed can be increased when there is no load or a light load, and the thrust can be increased when the load is high. For example, a high thrust can be obtained only during molding in a press machine, etc. Since it is possible to operate at high speed in other stroke ranges, it is possible to significantly improve work efficiency.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the second embodiment, and FIG. 3 is a conventional cross-sectional view. 1... Valve body, 6, 7... Spool, 10-1
3... Chamber, 28... Discharge channel, 29... Supply channel, 31, 32... Through hole, 35, 36... Actuator channel, 37... Cylinder, 38... Bottom side chamber, 39... Rod side chamber, 40, 41...pilot channel, 42, 43...detection orifice,
50... Tank, 51... Pump, 52... Switching valve, 58... Check valve, 64... Set pressure detection valve, 65... Relief valve as another example of set pressure detection valve, 60... Distribution Road, 68...tank.

Claims (1)

[Claims] 1. A pair of spools each having two chambers are provided in the valve body, and the chamber on one side of one of the spools is communicated with the bottom side chamber of the cylinder via the actuator channel, and the chamber on one side of the other spool is connected to the bottom side chamber of the cylinder through the actuator flow path. the chamber is communicated with the rod side chamber of the cylinder via an actuator flow path different from the above, and a pair of pilot flow paths communicated with the actuator flow path are respectively communicated with the switching valve,
The pilot passages are connected to the chamber on the other side of each of the spools, and a detection orifice is provided in the flow process between the chamber on the other side and the actuator passage, and each of the pair of spools has a main passage. A control valve device in which a hole is provided, and the main passage hole connects or blocks one side of the chamber with either a discharge channel leading to a tank or a supply channel leading to a pump, depending on the movement position, In addition to the main through hole, the spool leading to the rod side is provided with a sub-hole that always communicates with the supply flow path. A check valve is provided with a flow passage communicating with the through hole, and a valve is provided in the pilot flow passage leading to the rod side chamber, which connects the pilot flow passage with the tank when the bottom side chamber reaches a set pressure. A control valve device that constitutes a dynamic circuit.