JPS604362B2 - Acceleration/deceleration circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration/deceleration circuit for a fluid pressure system, and more particularly to an efficient acceleration/deceleration circuit that performs meter-out control by reducing inflow side pressure at least during deceleration.

Conventionally, circuits that form a closed circuit and are capable of performing regenerative braking have been considered to have good acceleration/deceleration efficiency. This is because acceleration/deceleration control is performed by controlling the discharge amount of the pump, and the pressure during acceleration/deceleration can always be applied at the maximum differential pressure set by a relief valve or the like. Closed-circuit systems are also well known for their ability to control acceleration and deceleration very smoothly. These excellent characteristics come into full play as the output horsepower increases or the inertia of the controlled object increases. However, the biggest disadvantage of this system is that the pump must correspond to each controlled object, that parallel circuits cannot operate simultaneously for the purpose of acceleration/deceleration control, and that the maximum speeds of each circuit are different. In this case, it would be troublesome to control each pump part individually, so an acceleration/deceleration control circuit using an improved control valve device proposed on the same day (Patent Application Publication No. 86121 of 1972) was designed to control the pilot flow rate. A main flow rate with a magnification equal to the ratio of the closed area of the flow detection orifice to the open area of the variable main orifice for the main flow is generated, and the pilot flow is controlled by a directional control valve and a flow rate control valve, and the variable main flow rate is The acceleration/deceleration of the main flow is controlled by controlling the opening of the orifice using the hydraulic pressure extracted from the pilot flow, so the optimal circuit configuration for smooth acceleration is achieved by meter-in acceleration up to the middle of acceleration. After passing a certain point, the system automatically and steplessly switches to meter-out control, and when decelerating, the meter-out control is used to perform smooth acceleration/deceleration control even in parallel circuit operation.

However, if we carefully consider the acceleration/deceleration efficiency of such a circuit configuration, we will find the following irrationality peculiar to open circuits: the efficiency is not good, and the deceleration efficiency is particularly significant. That is, during acceleration, when meter-in control is performed, the return side pressure is about the same as the pipe resistance, and the load pressure effectively acts for acceleration. However, at the same time as it switches to meter-out control, resistance pressure is generated on the return side, and the pressure that effectively acts for acceleration is the pressure difference. During deceleration, the pressure on the inflow side increases to the input pressure (relief pressure of the main circuit) due to meter-out control, so the pressure on the return side may become quite high, and an overload relief is generally provided in such cases. Therefore, it is the pressure difference between the overload relief and the main relief that effectively affects the deceleration. Therefore, according to the general wisdom of hydraulic circuits, the maximum pressure cannot be set to a very high pressure even in an overcode circuit, so the deceleration efficiency is not good. Therefore,
In order to increase the acceleration/deceleration efficiency, the circuit should be configured so that during acceleration, the stopper control is performed until the maximum distance possible. It is desirable to perform the close-out control only in order to prevent the accidental push-off phenomenon.

Based on the above considerations, the present invention provides an acceleration/deceleration circuit that is equipped with a device for depressurizing at least the pilot circuit on the inflow side during deceleration among the circuits on the inflow side and the discharge side of the pilot flow in the acceleration/deceleration circuit proposed separately above. By providing a deceleration circuit,
It is an object of the present invention to provide an acceleration/deceleration circuit that prevents return side pressure from becoming high during deceleration and increases deceleration efficiency. To this end, the present invention provides a main circuit connecting a load to two external boats connected to a fluid pressure source and a reservoir, and normally interrupts said main circuit and switches either said main circuit depending on the displacement from said cut-off position. A first spool that selectively passes through one of the external boats, and a first spool that is interposed in the main circuit on the load side of the first spool and normally shuts off the main circuit and changes the main circuit depending on the displacement of the first spool. A variable main orifice section consisting of a second spool that increases or decreases the passage area to form a variable main orifice section, a pilot circuit connected to a load and equipped with a detection orifice, and a pilot circuit that is selectively connected to a fluid pressure source or a switching valve that connects or shuts off the reservoir, a passage that guides the pressure on the opposite load side of the variable main orifice to one end surface of the first spool, and a passage that guides the pressure on the opposite load side of the detection orifice to the first side. A passage leading to the pond-side end face of the spool, and a flap interposed in the pilot circuit.

- a control valve and a second valve constituting the variable main orifice section for controlling the fluid pressure generated in the pilot circuit;
A variable orifice control circuit that guides the spool to a selected end face of the spool. An acceleration/deceleration circuit is constructed by providing a flow control valve installed in the system and a device for reducing the pressure of the supply side pilot circuit at least during deceleration in the pilot circuits of the two circuit systems. Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a control valve device 1 according to the present invention, in which a valve body 2 has two valve holes 3a, 3 vertically arranged in parallel.
b and pilot passages 4a, 4b are provided.
two annular grooves 5, 6, a supply boat (external boat) 7 and a pilot passage 8, which are connected to one annular groove 5;
, a discharge boat (external boat) 9 and a pilot passage 10 are provided which fit over the other annular groove 6 . Valve hole 3
Cylindrical spools 12a and 12b having through holes 11a and 11b on their sides are slidably inserted into a and 3b, respectively.
Further, central partition walls 13a and 13b provided inside the chambers 14 and 15 and chambers 16 and 17 are defined on each side. These spools 12a, 12b are usually valve holes 3a, 3.
It is kept in a neutral position with respect to b. For this purpose, the valve hole 3
Guides 18 and 19 extending from the upper ends of chambers 14 and 16 in a and 3b protrude into the spools 12a and 12b, and spring receivers 2 inserted into the base end portions of these guides 18 and 19
Center springs 26 and 27 are interposed between the spring receivers 24 and 25, which are inserted into the tip portions while keeping the locked state through the flanges 22 and 23 as in 0 and 21, and these spring receivers 20 and 21 are attached to the spool. 12a, 12b side, and the other spring receiver 24, 2
5 to the central partition wall 13a of the spools 12a, 12b,
13b, this center spring 26
, 27, the normal spools 12a, 12
b is maintained in a neutral position with respect to the valve holes 3a and 3b. Further, through holes 11a bored in the side surfaces of the spools 12a and 12b,
11b is in all cases communicated by internal passages 30, 31 to the chambers 15, 17 side and spools 12a, 1
2b is in the neutral position, the valve hole 3a is located between them so as not to communicate with either of the annular grooves 5, 6.
, 3b. As a result, the through hole 11
a, 11b closes into either one of the annular grooves 5, 6 in accordance with the emotional movement of the spools 12a, 12b, thus opening the chambers 15, 17 toward the annular grooves 5 or 6 depending on the direction of movement. Suitable. Detection orifices 32 and 33 are installed in the middle of the pilot passages 4a and 4b, respectively, and the pilot passages 4a and 4b on the anti-load side of the detection orifices 32 and 33 are connected to the chambers 14 and 16 of the valve holes 3a and 3b. are transported by passages 34 and 35, respectively.

On the other hand, a spool 42 is provided on the load side of the valve body 2 so as to be able to slide freely within a cylinder 41 extending laterally, and a central land portion 43 of this spool 42 and the inner wall of the cylinder are connected with a seal 44 interposed between the spool 42 and the cylinder 41 extending laterally. Taper portions 45 and 46 are formed on both sides of the central land portion 43 at a distance from each other.

The taper on the surface of the tapered part is given an inclination corresponding to the controlled addition/deceleration curve, so that the maximal part can be brought into close contact with the inner wall of the cylinder at the neutral position. Land portions 4 are provided at both lateral ends of the tapered portions 45 and 46.
7 and 48 are formed and are in close contact with the inner wall of the cylinder, and these central land portion 43, tapered portions 45 and 46, and land portion 4
Annular grooves 49, 50, 51 are provided on the inner wall of the cylinder between 7 and 48.
, 52 are provided in order to connect the pilot passage 4 to the pilot passage 4.
a, the grooves pass through the chamber 15 of the valve hole 3a, the chamber 17 of the valve hole 3b, and the pilot passage 4b, and the annular grooves 49, 52 are suitable for reaching the take-out boats 53, 54 on the actuator side, respectively. Chambers 55 and 56 are provided at the left and right ends of the cylinder 41,
A spring 57 that always biases the spool 42 to the right is interposed in the left end chamber 56, while a stopper 95 that restricts the rightward movement of the spool 42 is adjustable from the outside of the valve body. The stopper 96, which similarly limits the leftward movement of the spool 42, also extends into the left chamber 56 in a freely adjustable manner from the outside of the valve body. Adjustment of this stopper 95 restricts the rightward movement of the spool 42, that is, the maximum value of the fluid flow path area constituted by the tapered portions 45, 46 of the spool 42 and the inner wall of the cylinder. This is to limit the leftward movement of 42, that is, to limit the maximum value of the flow path area. Both chambers 55 and 56 on the left and right sides of the cylinder are fitted with a boat 6 that is suitable for the outside.
0 and 61, respectively. Therefore, the cylinder 41 and the spool 42 are connected to the chambers 55 and 5 which communicate with the boats 60 and 61.
The spool 42 slides inside the cylinder 41 due to the differential pressure of 6, and the tapered portions 45 and 46 shown in the figure are in close contact with the inner wall of the cylinder, that is, the annular grooves 49 and 50 and the annular grooves 51 and 52 are blocked, respectively. The spool 42 moves leftward or returns to form a variable main orifice that linearly changes the closed area between the tapered portions 45, 46 and the inner wall of the cylinder. The pressure on the opposite load side of the variable main orifice, that is, the pressure on the opposite load side of the tapered portions 45 and 46, is transferred to the chambers 15 and 17 on one side of the first suburs 12a and 12b via the annular grooves 49 and 51, respectively. be introduced. Next, as an example of a circuit formed by configuring a valve assembly using a built-up type integrated valve unit on the control valve device 1 described above, the direction and speed setting circuit section shown in FIG. and the variable main orifice control circuit section.

A pilot passage 8 carrying the supply port 7 through the annular groove 5 is connected by a passage 58 to a boat of a spring-offset solenoid directional valve 40 in the 4-boat 2 position, while the annular groove 6 is connected to the discharge boat 9. The pilot passage 1 and the other boats are connected to each other via a passage 59. One of the remaining boats of this directional control valve 40 is connected to a passage 77 in which a check valve 76 is interposed, and the other is connected to a passage 79 in which a pressure reducing valve 39 and a check valve 78 are interposed.
The two passages 77 and 79 merge to form the passage 66.
Flow control with pressure compensation in meter direction
The four boats are connected to one boat of a three-position spring offset electromagnetic directional control valve 67 through a valve 65, and the other boats of this directional control valve 67 are connected to the above-mentioned passage 59 through a passage 68. The check valves 76 and 78 both prevent flow from the directional control valve 67 toward the directional control valve 401. Moreover, the pilot passage 4b of the control valve device 1
, 4a are connected to the switching valve 67 through passages 74 and 75 having pressure-compensated flow control valves 72 and 73 in the meter-out direction, respectively, and are further connected to the take-out boats 53 and 5.
4 are respectively passed through the boats 70 and 71 of the motor 69,
The supply boat 7 is connected to a fluid pressure source such as a hydraulic pump, and the discharge boat 9 is connected to a reservoir side such as a tank. Regarding the flow rate setting, the set value of the meter-out flow control valves 72 and 73 is set smaller than that of the meter-in flow control valve 65.
On the other hand, referring to the variable main orifice control circuit section which is parallel to the directional speed setting circuit section having the switching valves 40 and 67, the pilot passage 8 on the supply side of the control valve device 1 is connected via a passage 81 having a pressure reducing valve 80. The pilot passage 10 on the discharge side is also connected to the switching valve 82 via a passage 87, and the cylinder of the variable main orifice at the bottom of the control valve device 1 The boat 60 suitable for the stone chamber 41 and the boat 61 suitable for the left chamber are equipped with flow control valves 83 and 8 with pressure compensation in the meter-out direction, respectively.
The switching valve 82 is connected to the switching valve 82 through passages 85 and 86 provided with the switching valve 82.

Next, we will discuss its operation. In the conditions shown in Figures 1 and 2, there is no fluid flow within the circuit. This is because the supply boat 7 of the control valve device 1 is closed by the spools 12a, 12b at the annular groove 5 of the valve body 2, and the pilot passage 8, which passes through this annular groove 5, and the one-way switching valve 40. Lower layer - Passage 77 - Passage 66
The pilot flow of the control valve device 1 is closed at the switching valve 67, and the passage 81 through which the pressure oil passes through this pilot passage 8 passes through the left position of the switching valve 82 and via the passage 86, and the control valve device 1 is controlled. Even if pressure oil tries to flow into the chamber 56 from the boat 61 of the main orifice, the land portion 47 at the right end of the spool 42 comes into contact with the stopper 95 and the spool 4
This is because there is no movement of fluid within the circuit since the right row of No. 2 is restricted. From this state, if the switching valve 67 is energized and switched to the left position for forward rotation of the motor 69, and the passage 66 and the passage 74, and the passage 75 and the passage 68 are made to pass through each other, now,
Since the lower order of the directional valve 40 is connected to the passage 58 and the passage 77 as well as the passage 59 and the passage 79, the working fluid from the hydraulic source is transferred from the supply boat 7 of the control valve device to the annular groove 5 to the pilot passage 8 to the passage 58. Lower direct passage 7 of one-way switching valve 40
7 - the left chamber of the passage 66 and the switching valve 67 - the passage 74 - the pilot passage 4b - the annular groove 51 - the supply side pilot circuit passing through the take-out boat 54 is formed to be supplied to the motor 69, and the return fluid is supplied to the take-out of the control valve device. Boat 53 circular groove 49-
Pilot passage 4a - passage 75 - meter-out flow control valve 73 - left chamber of switching valve 67 - passage 68
- A pilot circuit is formed through the pilot passage 10, the annular groove 6, and the discharge boat 9, and is discharged to the reservoir side. However, the switching valve 82 is located at the left position and the first
As shown in the figure, if the opening degree of the variable main orifice is zero, as a result, the fluid flow in the circuit remains only as the pilot flow, and only a small volume of working fluid is supplied to the motor 69. In general, the pilot flow rate is very small compared to the maximum value of the main flow, so even if the pilot flow occurs, no impact will be generated on the load due to the cushioning effect of the pipe volume of the motor after the directional control valve 67. Depending on the size of this cushioning effect, a stopper 9 may be applied from the outside.
5 may be moved to the left to unwrap the opening degree of the variable main orifice in advance to increase the main flow described later from the beginning. From this initial state of acceleration, when the switching valve 82 that controls the variable main orifice is energized and switched to the right position to allow passages 81 and 85 and passages 86 and 87 to pass through, the pilot passage 8 of the control valve device 1 Passage 81 - pressure reducing valve 80, right position of switching valve 82, variable main orifice chamber 55 from boat 60 via pilgrimage 85
The working fluid is introduced into the spool 42 and the spring 57
Since it is moved to the left against the elasticity of the cylinder 41, a clearance is generated between the tapered portions 45, 46 and the inner wall of the cylinder 41, that is, the relationship of the variable main orifice gradually increases.

In addition, the return fluid from the other chamber 56 passes through the boat 61 and is discharged to the reservoir side through the passage 86 - the meter-out control flow control valve 84, all to the right of the changeover valve 82, the passage 87 - the pilot passage 10, the annular groove 6, and the discharge boat 9. Ru. Then, the flow rate is detected by the detection orifice 33 of the pilot passage 4b, and the differential pressure due to the pressure drop of the pilot flow that occurs before and after the flow passes through the passage 35 as the upstream pressure (counter-load side pressure) of the detection orifice, respectively, to the valve hole 3b. The pressure is transmitted as downstream pressure (load side pressure) to the chamber 17 of the valve hole 3b through the entrance of the variable main orifice, and the spool 12b is lowered by the differential pressure. The pressure actually transmitted to the chamber 17 is the pressure on the opposite load side of the variable main orifice. However, when the variable main orifice is fully open, the pressure loss of the variable main orifice becomes small, and the pressure transmitted to the chamber 17 can be considered to be a pressure corresponding to the load side pressure of the detection orifice 33. During the transient period until the variable main orifice is fully opened, the anti-load side pressure of the variable main orifice, which is greater than the load side pressure of the detection orifice 33, is transmitted to the chamber 17 through the annular groove 51, slowing down the downward speed of the spool 12b. Spool 1
As the spool 2b descends, the annular groove 5, the internal passage 3'1, and the chamber 17 flow through the through hole 11b of the spool 12b, and the working fluid from the liquid pressure source flows from the supply boat 7 to the annular groove 5 in the chamber 17.
1 - Variable main orifice opening by tapered section 46 of spool 42 passes through annular groove 52 and joins the pilot flow here, from take-out boat 54 to boat 7 of motor 69;
1, a main circuit for driving the motor 69 is generated, and the main circuit on the return side is similar to the flow in the chambers 14 and 15 in the valve hole 3b in approximately correspondence to the differential pressure before and after the detection orifice 32 in the pilot passage 4a. A differential pressure is generated in the spool 12a, which causes the spool 12a to rise and communicate between the annular groove 6 and the internal passage 30 through the through hole 11a. orifice closing part annular groove 50 in the tapered part 45 - chamber 15 of the valve hole 3a
A main circuit on the return side is formed through which the liquid is discharged to the reservoir side through the single hole 11a, the circular groove 6, and the discharge boat 9. When the main flows on the supply side and the return side are formed in this way, a pressure difference is generated before and after the variable main orifice formed by the tapered portions 45, 46 of the spool 42 and the inner wall of the cylinder 41, and the pressure in the chambers 15, 17 is generated. Since the influence of the pressure drop effect appears in the supply side spool 12b, a downward thrust due to the anti-load side pressure of the pilot flow detection orifice 33, the elasticity of the center spring 27, and the anti-load side of the variable main orifice is generated on the supply side spool 12b. The spool 12a on the return side balances the upward thrust caused by the pressure of the main flow and remains stationary at the position, and the return side spool 12a balances the upward thrust caused by the pressure of the pilot flow and the downward thrust caused by the pressure on the anti-load side of the pilot flow detection orifice 32, and the elasticity and variableness of the center spring 27. It comes to rest at a position that balances the upward thrust due to the pressure on the opposite load side of the main orifice.

Now, the relationship between the flow rate q flowing through the pilot passages 4a and 4b, the closed area s of the detection orifices 32 and 33, the flow rate Q of the main flow, and the closed area S of the variable stopper orifice is approximately Q no q≠S/s. It is known that the flow rate q of the pilot flow from the direction (detailed in the said patent application specification),
Controlled by a meter-out flow control valve 73 in the speed setting circuit and flow control valve 83 or 8 in the variable main orifice control circuit.
If the opening degree of the variable main orifice is adjusted according to the acceleration curve by appropriately adjusting 4, since s is constant, the flow rate Q of the main flow corresponding to the appropriate acceleration curve of the desired motor can be determined. .

Here, as mentioned above, a pressure-compensated flow control valve is used in the pilot circuit, and the meter-out flow control valves 72 and 73 are always set slightly smaller than the meter-in flow control valve 65. Since the meter-out control is always performed during acceleration, the meter-in flow control valve 65 does not substantially operate, so that an effective pressure difference can be used for acceleration.

Therefore, the actuator such as a motor can accelerate to the maximum speed with high acceleration efficiency while maintaining a desirable acceleration state without shock. However, here the meter
We must pay careful attention to the fact that the meaning of "meter-out" is different from the conventional concept of flow rate control; it is meant to express a form of control that smooths out the acceleration/deceleration diagram, which includes not only flow rate but also pressure. No. Next, deceleration control will be explained.

From the state where the motor 69 is controlled at the maximum speed, that is, the state where the variable main orifice is at its maximum opening, the switching valve 82 is switched to the left position, that is, passages 81 and 86, passages 85 and 8.
7 is placed in a suitable position, the working fluid from the fluid pressure source enters the left chamber 56 of the variable main orifice through the passage 81, the sliding valve 82 and the passage 86, causing the spool 42 to move to the right and reaching the tapered portions 45 and 46. The opening degree of the configured variable main orifice is gradually narrowed, and the return fluid is discharged to the reservoir through the passage 85 - the flow control valve 83 in the meter out direction, and the switching valve 82 - the passage 87. The rightward speed of the spool 42 is controlled by adjusting the flow control valve 83 of the return circuit. On the other hand, when the switching valve 40 is also excited at the same time as the switching valve 82 is excited, and the upper layer, that is, the passage 58 and the passage 79, and the passage 59 and the passage 77 are switched to a suitable position, the supply side flow of the pilot circuit is Upper calendar of one-way switching valve 40 - passage 79
After the pressure is reduced by the pressure reducing valve 39, the passage 66 flows to the left side of the sliding valve 67 and passes through the passage 74 to the motor, and the return flow passes through the passage 75 to form a flow in the meter-out direction. Since the main flow is subjected to meter-out control by the control valve 73 and passes through the switching valve 67 and the circuit 68 to the reservoir, the main flow follows this in an amplified form, and the pressure on the inflow side to the load is reduced despite the meter-out control. Since the return side pressure is prevented from becoming a considerably high pressure and no overload relief valve is required, the deceleration is performed with a fairly good deceleration efficiency, and is stopped by demagnetizing the cut-off valves 67 and 82. In addition, the main flow during deceleration is operated to be opposite to the flow during acceleration, and the right position of the switching valve 6.7 is for reversing the motor, and the main flow is operated in the opposite direction to the flow during acceleration.
8 and 74, but the operation is simply the opposite of the normal rotation described above, so the explanation will be omitted. The embodiment shown in Fig. 2 assumes parallel operation and adopts a method in which the pressure on the inlet side is reduced during deceleration, but if only independent operation is required, switching the main circuit pressure to a low pressure will reduce heat generation. This is a more effective method in terms of power loss.

Next, the embodiment shown in FIG. 3 operates to automatically detect the pressures of both boats of the load using a switch valve and bypass a portion of the pilot flow on the low pressure side to the return circuit. .

That is, what is shown in FIG. 3 is the directional control valve 40 shown in FIG.
, the pressure reducing valve 39, the check valves 76, 78, and the passages 77, 79 are omitted, and instead, the passage 58 of the pilot circuit and the passage 66 are directly communicated to connect the pilot passage 8 of the control valve device 1 to the meter inflow control valve 65. It is connected to the port of the directional control valve 67 via the passage 74 and the pressure difference between the passage 74 and the passage 75, and the pressure oil on the low pressure side is connected to the passage 89 via the relief circuit, that is, the low pressure relief valve 88. A pilot type switch valve 92 is installed to allow the return to the reservoir via the passageway 68.

3 is stopped in the state shown, ie, passage 74 is cut off from the relief circuit in which the low pressure relief valve 88 resides, while the other passage 75 is in close contact with this relief circuit. It is assumed that the motor 69 is an inertial body and is placed in a state where it does not generate pressure on any of its own boats when stopped. Now, when the directional control valve 67 is energized and moved to the left position, the pressure oil flows through the passage 66 of the pilot circuit.
-Meter inflow control valve 65 - Pilgrimage 74
However, if the opening degree of the variable main orifice is zero, the flow to the motor is only this pilot flow, and this pilot circuit on the supply side boosts the pressure.
Since the return circuit, ie, the passage 75-circuit 68-reservoir circuit, is maintained at low pressure, switch valve 92 is configured to connect the pilot flow in passage 75 to the return circuit via the low pressure relief valve 88-passage 89. take a position. In this state, the motor starts at a slow speed, and as the directional control valve 82 is excited and switched to the right position, the relationship between the variable main orifice increases as described above, and the amplification factor between the pilot flow and the main flow increases. The meter flow is controlled and the pressure on the return side is low, so it is accelerated in such a way that the supply pressure can be effectively used as acceleration energy. When the switching valve 82 is demagnetized and switched to the left position during acceleration or at maximum speed, the opening degree of the variable main orifice becomes smaller, the amount of pressure oil supplied to the motor decreases, and the pressure on the passage 74 side drops rapidly. The switch valve 92 is switched to assume the right position to connect the passage 74 to the low pressure relief circuit (passage 89) and to cut off the connection of the passage 75 to the low pressure circuit of the pilot circuit. Meter out flow control valve 7 at the same time as cutting sliding door
3, it enters a deceleration state. This state is passage 7
4, 66 is maintained at a low pressure regardless of the main circuit pressure due to the relationship between the meter flow control valve 65 and the switch valve 92, so the deceleration is achieved by cutting off the influence of the main circuit pressure and achieving the highest efficiency. kept in a decelerated state. Note that this circuit can also be used as a conventional counter circuit that does not cause hunting. As described above, according to the present invention, even when controlling a large capacity/high pressure load, acceleration/deceleration operations can be performed without shock while maintaining an appropriate acceleration/deceleration force curve, and the operation is extremely easy and requires little effort. In both cases, at least meter-out control can be performed efficiently by reducing the pressure on the inlet side during deceleration, and efficient control of acceleration can be performed during acceleration by adjusting the flow control valve adjustment specifications or by reducing the return side pressure. These can be controlled simultaneously in parallel circuits, and furthermore, by combining with other circuit specifications, the control specifications can have great flexibility.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of a control valve device according to the present invention, and FIG.
The figure is a circuit diagram showing an embodiment of an acceleration control circuit according to the present invention,
FIG. 3 is a circuit diagram showing an acceleration/deceleration control circuit according to another embodiment of the present invention. 1...Control valve device, 3a, 3b...Valve hole, 4a, 4b,
8, 10... Pilot passage, 7... Supply boat (
external boat), 8...discharge boat (external boat), 1
2a, 12b...Spool (first spool), 32, 3
3...Detection orifice, 39...Pressure reducing valve, 41...Cylinder, 42...Spool (second spool), 45,4
6... Taper part, 53, 54... Take-out boat, 65, 7
2, 73, 83, 84...Flow control valve, 4
0, 67, 82... Directional sliding door valve, 88... Low pressure relief valve, 92... Switch valve. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 A main circuit that connects a load to two external ports that connect to a fluid pressure source and a reservoir, and normally cuts off the main circuit and switches the main circuit to either one of the external ports depending on the displacement from the cutoff position. A first spool that selectively communicates with the port, and a first spool that is interposed in the main circuit on the load side of the first spool and that normally blocks the main circuit and increases or decreases the passage area of the main circuit according to the displacement of the first spool. A variable main orifice section consisting of a second spool forming a variable main orifice section, a pilot circuit connected to a load and having a detection orifice interposed therein, and the pilot circuit selectively connected in communication with a fluid pressure source or a reservoir. a switching valve for shutting off, a passage for guiding the counter-load side pressure of the variable main orifice portion to one end surface of the first spool, and a passage for introducing the counter-load side pressure of the detection orifice to the other end surface of the first spool. a flow control valve interposed in the pilot circuit, and a variable orifice control circuit that guides fluid pressure generated in the pilot circuit to a selected end surface of a second spool constituting the variable main orifice section. and a flow control valve interposed in the variable orifice control circuit, and a flow control valve interposed in the variable orifice control circuit; An acceleration/deceleration circuit characterized in that the pilot circuits of the two circuit systems are provided with a device for reducing the pressure of the supply side pilot circuit at least during deceleration.