JPH0768963B2 - Hydraulic 3-port continuous valve and hydraulic control device using the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a spool slidably guided in a housing for connecting a load connection to an inflow connection or a return connection, or to these. The pressure of the load connection port acting on the spring and the second pressure surface is cut off from both connection ports, and the load is applied to the direction of the initial position excluding the pressure of the load connection port through the return connection port, and the first control is performed. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block built-in hydraulic 3-port continuous valve that receives a control pressure applied to a connection port in a reverse direction on a first pressure surface, and a hydraulic control device using the same.

[Conventional technology]

Such a three-port continuous valve is known from DE-A 3203533 and has, in addition to the pressure faces provided on the two end faces, only one connecting port. Such 3-port continuous valves are often advantageous over block-incorporated 2-port continuous valves. Because this valve combines the functions of the two individual resistors, it makes the electromechanical converter relatively low in cost. However, a disadvantage of this three-port continuous valve is that its functional content is limited by the same size pressure surface and only one control connection. If a 3-port continuous valve is assigned to multiple functions in multiple control devices and its diverse uses fulfill a large number of functions with as few built-in valves in the output circuit as possible, such a 3-port continuous valve will meet demand. Sometimes I can't This is especially true for control pressure control in the safe case when some pilot control circuit fails.

Furthermore, in the control device known from DE-OS 28 4965, the direction and speed of the double-acting hydraulic motor are influenced by the changing load direction of the external load and are controlled by a two-port valve. . For volumetric flow control, a 2-port continuous valve configured as a seat valve and pilot-controlled by a 4-port 3-position port valve is used,
A total of four 2-port seat valve cartridges are used for directional control. The disadvantage of this device is the high cost of the valve. This is because these valves and the additional check valves for the differential connections have to be adjusted to the required rated volume. Moreover, a large number of hydraulic components are required due to the control side of the built-in valve. A continuous valve with a differential piston and position adjustment has a relatively small functional content of the valve, because it has only two controlled displacements, and the valve is configured to be pressure balanced against the inflow pressure. Not particularly disadvantageous.

In a further earlier application, it has already been proposed to control a double-acting hydraulic motor via two built-in three-port continuous valves, each pilot valve belonging to a main stage being in the regulating circuit. In this case as well, the functional content of the 3-port continuous valve is limited, which results in insufficient fail-safe operation in case of a failure of the electrical control circuit. In particular, the braking force capable of slowing down the movement of the load connected to the double-acting hydraulic motor is due to the pressure drop that occurs in each case when the prevailing main stage in the output section flows from the motor connection port to the return connection port. Only determined.

[Problems to be Solved by the Invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic three-port continuous valve having a simple and compact structure and a remarkably large function content, and a hydraulic control device using the same to perform a fail-safe function.

[Means for Solving the Problems]

In order to solve this problem, in the continuous valve according to the present invention, the first
Has a larger pressure surface than the second pressure surface, the spool has an additional control edge and the housing is provided with a second control connection, the control edge controlling the connection of both control connections.

According to the invention, the hydraulic control device for controlling the hydraulic pressure supplied to the load includes at least one hydraulic 3-port continuous valve, which is slidably guided in the housing. Spool that connects the connection port to the inflow connection port or the return connection port, or disconnects from both these connection ports, and the direction of the initial position where the pressure of the load connection port is removed via the return connection port by the pressure of the spring and the load connection port A second pressure surface of the spool to be loaded to the spool, and a spool first receiving a control pressure that is greater than the second pressure surface and is applied to the first control connection port or the second control connection port in the housing in the opposite direction. 1
With a pressure surface and an additional control edge of the spool which controls the connection between the first and second control connections, both control connections of the pilot valve associated with the continuous valve. The pressure acting on the first pressure surface of the continuous valve, which is connected to the motor connection port, has its pressure value limited by the pressure control valve for pilot control, and the control oil flows from the inflow connection port of the pilot valve through the pilot control circuit. Can be supplied, the control member of the pilot valve is loaded by the spring towards the safe position,
In this safe position, the inlet connection of the pilot valve is connected via the first throttle to the motor connection connected to the first control connection of the continuous valve and flows out via the second throttle. Another motor connection port connected to the connection port and having a larger flow cross section of the first throttle than the flow cross section of the second throttle and connected to the second control connection port of the continuous valve at this safety position is an outflow connection. Connected to the mouth.

〔The invention's effect〕

In the continuous valve according to the invention, the first pressure surface is larger than the second pressure surface and the additional control edge formed on the spool is
By controlling the connection between the first control connection port and the second control connection port, the functional content of the continuous valve is expanded. That is, in the zero position where the control pressure is applied to the first pressure surface of the spool and both control connection ports are connected to each other via the connection edge, the load connection port is disconnected from the inflow connection port and the return connection port, At the initial position where no pressure acts on the first pressure surface, both control connection ports are disconnected, the load connection port is disconnected from the inflow connection port, and the pressure is removed via the return connection port. However, between the initial position and the zero position, the spool takes the braking position, changes the flow cross section from the load connection port to the return connection port, and controls the connection of both control connection ports by the control edge, The load connected to the load connection port, for example, the return speed of the hydraulic motor is adjusted. When the pressure acting on the first pressure surface from the first control connection port is high,
The spool takes the operating position, disconnects the load connection port from the return connection port, and changes the flow cross section from the inflow connection port to the load connection port to adjust the operating speed of the load. The control edge then completely connects the first control connection and the second control connection. Unlike conventional continuous valves in which the first pressure surface and the second pressure surface are the same size and have only one control connection, the continuous valve according to the present invention has a first pressure surface and a second pressure surface.
Since it has a size different from that of the pressure surface and has two control connection ports, and the connection is controlled by the control edge, various adjustments can be made in the operating position and the braking position of the spool.

Further, in the case of fail-safe, the hydraulic pressure control device including the continuous valve according to the present invention can dampen the load subjected to the action of the external force to attenuate the kinetic energy of the external force acting on the load. That is, when an external force acts on a load, for example, a hydraulic motor, the piston is pushed back and a corresponding pressure is generated at the load connection port of the continuous valve and acts on the second pressure surface. On the other hand, the control oil acts from the inflow connection port of the pilot valve, the first throttle and the motor connection port to the first pressure connection surface of the continuous valve through the first control connection port. First
Since the throttle has a larger flow cross section than the second throttle in the connection path from the inflow connection port to the outflow connection port, pressure by control oil can be generated in the first control connection port. This pressure can be limited to the desired value by the pressure control valve. Thus, the spool of the continuous valve takes a braking position according to the pressure of the load connection port acting on the second pressure surface and the pressure of the first control connection port acting on the first pressure surface, and at this position, the load connection port. The connection path from to the return connection port is narrowed. Thereby, the kinetic energy of the external force acting on the load can be attenuated as desired. In this way, in order to attenuate the kinetic energy of the external force in the case of fail safe, the spool of the continuous valve, the pilot valve and the pressure control valve effectively act as the control valve which is pilot-controlled.

〔Example〕

FIG. 1 shows, in a longitudinal section, a hydraulic three-port continuous valve 10 containing a spool 12 movable in a longitudinal direction in a housing 11. In a continuous valve designed for block installation, the housing 11 consists of a housing sleeve 13 and an associated housing lid 14. As is known, three working connection ports are formed in the housing sleeve 13, of which the inflow connection port P is 15, the load connection port A is 16, and the return connection port T is.
Shown at 17.

At the end of the spool 12 on the side opposite the load connection A, the spool 12 has a piston part 18, which part 18
Defines a pressure space 21 by the first pressure surface 19 at the end surface. The pressure space 21 has a passage 22 extending through the housing lid 14.
Is connected to the first control connection port 23 via. In the area of the piston part 18, the housing sleeve 13 has an annular groove on the inside.
This annular groove 24 is connected to a second control connection 26 via a second passage 25 extending through the housing lid 14. The piston part 18 forms a control edge 27 by its end close to the pressure space 21, which control edge 27 connects the pressure space 21 to the annular groove 24, and thus both control connections 23 and 26.
Control connections. Extending from the control edge 27 into the piston portion 18 are a plurality of grooved precision control recesses 30 to facilitate control pressure regulation. A precision control recess 30 is formed in a length such that when the piston portion 18 hits the lid 14 in the initial position, the connection of the control connection ports 23 and 26 is blocked by a positive overlap.

The outer diameter of the piston portion 18 is larger than the diameter of the spool in the region of the working connections P, A, T, so that the first pressure surface 19 is larger than the second pressure surface 28 closer to the load connection A.
On the side of the second pressure surface 28, the spool 12 is additionally loaded by a spring 29. The area difference between both pressure surfaces 19, 28 is chosen to be at least That is, the same pressure on both pressure surfaces causes an excess force with respect to the force of the spring 29, which pushes the spool 12 to the illustrated null position, in which case the connection from the load connection A to the return connection T is made. It is blocked by the zero overlap of the control edges or is tightly squeezed initially. The spool 12 is further connected to an electromagnetic displacement detector 31,
It is guided in its rotational position by a pin-slit joint 32. In the 3-port continuous valve 10, a control edge having a precision control recess 30 with two individual resistances between the operation connection ports P, A and T.
The additional control functions are integrated by 27 and the pressure dependence is obtained by the differently sized pressure surfaces 19, 28, which expands the functional content of the continuous valve 10. When pressure is applied to the first pressure surface 19, the spool 12 takes the zero position 33 shown in the figure, at which position the inflow connection port P is shut off, and the connection from the load connection port A to the return connection port T is shut off. At the same time, the first control edge 27 opens the connection of both control connections 23, 26. If there is no control pressure in the pressure space 21, the spring 29 pushes the spool 12 into the housing 13 into the initial position 34, at which position the load connection A is returned to the connection T, the pressure is released, and the inflow connection P is blocked. Then, the connection of both control connection ports 23, 26 is cut off. The braking pressure can be adjusted between the initial position 34 and the zero position 33 (third position).
There is a range of braking positions 36. At the braking position 36, the connection from the load connection A to the return connection T is squeezed by a large or small amount, and the precision control recess 30 opens the squeezed connection of control oil. If the control pressure at the first control connection port 23 is high,
The spool 12 takes the operating position 35, at which position the connection path from the inflow connection port P to the load connection port A is opened large or small, the return connection port T is shut off, and the first control connection port 23 to the second connection port T are closed. Fully open the connection to the control connection 26. Depending on the adjustment function, the individual positions of the spool 12 will slowly transition to each other.

FIG. 2 shows a schematic diagram of the block-embedded 3-port continuous valve 10 according to FIG. 1 together with a pilot control circuit 38 for controlling a single-acting function. The same components as those in FIG. 1 are designated by the same reference numerals.

A 4-port 4-position proportional pilot valve 39 is inserted in the pilot control circuit 38, and its first motor connection port 41 is a continuous valve.
In the first control connection port 23 of 10, the second motor connection port 42
Is connected to the second control connection 26. Pilot valve
The inlet connection 43 at 39 is connected to the branch conduit 44 and the first check valve.
Is connected to the inflow conduit 46 via 45 and a second check valve 47
Is connected to the load conduit 48 via. Therefore, both check valves 45 and 47 have an OR function, so that control oil can be supplied to the control circuit 38 from both the inflow side and the motor side. A 4-port 2-position solenoid valve 49 that opens and closes is inserted in the branch of the control conduit 44 that leads to the inflow side, in series with the first check valve 45 and in parallel with the second check valve 47. Therefore, the control oil supply passage from the inflow conduit 46 can be opened or shut off. Outflow port of pilot valve 39
51 is depressurized to tank 52.

The pilot valve 39 has a vertical spool 53 which is loaded towards a safe position 55 by a spring 54, the vertical spool 53 being in a first (57), a second (58) and a third motion from a safe position by means of a proportional electromagnet 56. It is possible to move to position 59. The electromagnet 56 is in the closed position adjustment circuit 61. In the safety position 55 of the vertical spool 53, which is determined by the spring 54, the inlet connection 43 of the pilot valve 39 is connected to the first motor connection 41 via the first throttle 62. At the same position 55, the inlet connection port 43 has the second throttle.
It is connected to the outflow connection port 51 via 63. Vertical spool
The overlapping state at 53 is formed as follows. That is, in the safety position 55, although the pressure is removed to the outflow connection port 51 via the second throttle 63, the control oil necessary for controlling the three-port continuous valve 10 passes through the first throttle 62. It can flow to the first control connection 23 of the main stage 10. This is achieved by making the free-flowing cross section of the first throttle 62 larger than that of the second throttle 63. Further, at the safety position 55, the second motor connection port 42 is connected to the outflow connection port 51 without being throttled. At the operating position 57 adjacent to the safety position 55, a narrowed connection is maintained between the inflow connection port 43 and the first motor connection port 41, and the second motor connection port 42 and the outflow connection port 51 are blocked. Has been done. Second
In the operating position 58, all four connection ports 41, 42, 43, 51 are hydraulically shut off. At the third operating position 59, only the inflow connection port 43 and the second motor connection port 42 are shut off, and the pressure at the outflow connection port 51 is removed from the first motor connection port 41.

The position adjusting circuit 61 of the proportional pilot valve 39 is located in the main adjusting circuit 64. In this circuit 64, the position of the spool 12 of the 3-port continuous valve 10 is adjusted by the displacement detector 31 according to the target value specified in the electric input end 65. To be done.

First control connection 23 and pilot valve of 3-port continuous valve 10
The connection of 39 to the first motor connection 41 is protected by an adjustable pressure control valve 66 which acts as a pilot valve. There is a pressure adjusting valve 67 that can be further proportionally adjusted in parallel with the pressure control valve 66, and this valve 67 has a 2-port 2-position open / close valve.
68 is connected. Open / close valve 68 is shut off by a spring 69
, And can be moved to the conduction position 71 by an electromagnet.

A single-acting hydraulic motor 72 is connected to the load conduit 48.

The operation of the 3-port continuous valve 10 and its pilot control circuit 38 is as follows.

The 3-port continuous valve 10 enables speed control of the hydraulic motor 72 in relation to a setpoint signal defined at the electrical input 65.
Due to the pressure limitation of this speed control, the force limitation of the hydraulic motor 72 is superimposed, and the pressure control valve 66 and the pressure adjusting valve 67 work together with the 3-port continuous valve 10 for the pressure reducing function.

In normal operation, the pilot valve 39 is controlled in its operating position 57-59 in order to move the piston rod in the hydraulic motor 72 in both directions or to hold it in a specific position. When the longitudinal spool 53 is brought into its first operating position 57 for delivering the piston rod of the hydraulic motor 72, the control oil reaches the first control connection 23 of the main stage 10 via the pilot valve 39. ,
Thereupon, the spool 12 is moved to the left towards the operating position 35 against the force of the spring 29, at which position the pressure medium flows from the inlet connection 15 to the load connection 16 and then to the hydraulic motor 72. The speed of the piston rod fed out of the hydraulic motor 72 depends on the electric input end.
Related to the high signal level at 65. This is because the spool 12 opens the connection path in proportion to its size. Since the second motor connection port 42 of the pilot valve 39 is shut off during this feeding process, the control oil cannot flow out of the pressure space 21 via the second control connection port 26.

If one wishes to hold the piston rods of hydraulic motor 72 in their respective positions, the magnitude of the signal at electrical input end 65 will be reduced until spool 12 reaches its illustrated zero position 33. As a result, the load connection port A is separated from the inflow connection port P, and the connection to the return connection port T is also cut off. Spool 12
When it returns from its operating position to the illustrated zero position, the control oil must first escape from the pressure space 21 to the tank 52 via the pilot valve 39 in its third operating position 59. When the spool 12 reaches its zero position by the action of the spring 29, the longitudinal spool 53 of the pilot valve 39 takes its second operating position 58,
At this position, both motor connection ports 41, 42 are cut off. Therefore, the control oil cannot escape from the pressure space 21 of the main stage 10, causing the spool 12 to remain in its illustrated zero position.

The setpoint signal at the electrical input 65 is appropriately reduced, so that the pilot valve 39 is brought into its third operating position 59, in which position the first control connection 23 of the main stage 10 is brought into contact with the tank 52. When the pressure is released, the piston rod of the hydraulic motor 72 is pulled in due to the influence of an external load. Spring 29
The spool 12 to the right from the illustrated zero position to the braking position 36
Alternatively, it is further pushed into its initial position 34, the load connection A being depressurized to the return connection T.

A pressure limit is superimposed on this speed control during normal operation of the hydraulic motor 72 by means of the pressure control valve 66, which pressure limit is
It also limits the external force on the 72 piston rod. In this case, the pressure control valve 66 cooperates with the spool 12 of the 3-port continuous valve 10. The pressure acting on the load connection A acts on the second pressure surface 28 of the spool 12. Ignoring the relatively weak force of the spring 29, this pressure acting on the second pressure surface 28 is limited in height by the pressure control valve 66, taking into account the different areas of both pressure surfaces 19, 28. The pressure in the pressure space 21 becomes slightly lower. Therefore, considering the appropriate correction factor, the pressure control valve
66 limits the pressure of the load connection A and thus also the external force on the hydraulic motor 72.

Although the pressure control valve 66 is set to the maximum pressure value, the pressure adjustment valve 67 capable of proportional adjustment can perform the pressure limit control at the load connection port A in the range below the maximum pressure value. The on-off valve 68 must be brought to its conducting position 71. Pressure adjusting valve 67 spools the same
Acting as a pressure reducing valve with 12, the correction factor must be taken into account depending on the differently sized pressure surfaces and the spring 29.

Solenoid valve for speed control and pressure limitation in normal operation
49 is excited and therefore in its conducting position. Both check valves 45, 47 in the branched control line 44 are therefore
To produce the R function, the inlet connection 43 of the pilot valve 39 is supplied with control oil from the conduit with the highest pressure level. Therefore, when the pressure in the inflow conduit 46 is high, the control oil reaches the pilot valve 39 through the first check valve 45, and when the pressure in the load conduit 48 is high, the control oil operates the second check valve 47. After that, the pilot valve 39 is reached.

When the control circuit or output circuit loses all or part of the energy supply due to a power outage, electromagnetic current interruption, emergency interruption, cable breakage, etc., advantageous operation when the 3-port continuous valve 10 is fail-safe in addition to normal operation Must have. In such a case, the on-off valve 68 takes its blocking position 69 so that the pressure regulating valve 67 does not act. Similarly, the solenoid valve 49 is brought into its closed position by spring force, so that the supply of control oil from the inflow conduit 46 is eliminated. The vertical spool 53 of the pilot valve 39 is pushed into its safe position 55 by the spring 54, so that its inlet connection 43 is in the main stage.
The first control connection port 23 and the outflow connection port 51 of 10 are connected, but the latter connection is strongly restricted.

In case of fail-safe, the pushing force from the outside is the hydraulic motor.
Acting on the piston at 72, this produces a suitable pressure in the load conduit 48 and at the load connection A, where it likewise has a second pressure.
Acting on the pressure surface 28 of the. Control oil flow from load conduit 48 is second
It branches via the check valve 47 and supplies the control pressure medium to the control circuit 38. This control oil flow reaches the pressure space 21 via the first throttle 62 and the first control connection 23, where it acts on the first pressure surface 19. The flow section of the first throttle 62 is the second throttle 63 in the connection path from the inflow connection port 43 to the outflow connection port 51.
Since it is greater than that, pressure can develop in the first control connection 23. In the case of fail-safe, the control pressure generated in the pressure space 21 pushes the spool 21 to the left against the force of the spring 29 so that the spool takes its braking position 36, and at this position the load connection port A to the return connection port T is moved. The connection path is narrowed down large or small. Control edge at initial position 34 on spool 12
27 disconnects both control connections 23,26 but spool 1
In the braking position 36 of 2, the fine control recess 30 makes a narrowed connection of both control connections 23, 26, so that a small control oil flow flows out to the tank 52 via the second control connection 26 and the pilot valve 39. can do. This control oil flow, which flows in parallel to the control oil flow exiting via the pressure control valve 66, is so small that it does not hinder the pressure build up in the pressure space 21 and facilitates the vibration-free operation of the braking pressure adjustment. Only. The flow cross section opened by the precision control recess 30 for this purpose is designed to be appropriately smaller than that of the first throttle 62 in the pilot valve 39. The area difference between the two pressure surfaces 19, 28 allows a movement against the force of the spring 29, so that a throttling braking position 36 of the spool 12 is possible. At that time, since the height of the control pressure in the pressure space 21 is limited by the pressure control valve 66, the braking pressure control acts on the load conduit 48 in this way, and the kinetic energy of the mass acting on the hydraulic motor 72 is eliminated. . Therefore, in order to limit the maximum braking pressure in the case of failsafe, the spool 12, the pilot valve 39 and the pressure control valve 66 act particularly advantageously as a pilot-controlled braking valve. Even if the control edge 27 is already closed after the loss of kinetic energy, the control pressure in the pressure space 21 drops to the outflow connection 51 via the first control connection 23, the first throttle 62 and the second throttle 63. However, the spring 29 can bring the spool 21 to its initial position. Then hydraulic motor 72
Is completely depressurized to the tank.

FIG. 3 shows a control unit 80 for the double-acting hydraulic motor 81, and a 3-port continuous valve 10 having the pilot control circuit 38 of FIG. 2 is attached to each connection side of the hydraulic motor 81. In FIG. 3, the same reference numerals are used for the same components as in FIG. 2, and the pilot control circuit for controlling the cylinder space 82 of the hydraulic motor 81 is shown.
The reference numeral of the 3-port continuous valve 10 having 38 has no subscript, but the reference numeral of the 3-port continuous valve 10 'having the pilot control circuit 38' for controlling the annular space 83 of the hydraulic motor 81 has a subscript '. I have it. Furthermore, the 3-port continuous valve 10, 10 'is indicated by its open / close symbol in a simplified form. To make it easier to see, the actual value transmitter 31,31 ', pilot valve 39,3
Proportional electromagnets 56,56 'in 9', pressure adjusting valve 67, open / close valve 6
8, solenoid valve 49, and actual value transmitter 8 on hydraulic motor 81
Electrical connection to 4 is not shown.

The control device 80 for controlling the double-acting hydraulic motor 81 is generally obtained by doubling the device according to FIG. For simplification, only the inflow side branch of the branch control conduit 44 'in the pilot control circuit 38' is additionally connected to the 4-port 2-position solenoid valve 49 in the first pilot control circuit 38, so that The second solenoid valve becomes unnecessary.

The operation of the controller 80 is basically the 3-port continuous valve 10 of FIG.
It is applied to the double-acting hydraulic motor 81 although its function is substantially the same. Pilot valve 39,3 attached to continuous valve 10,10 '
By controlling 9'in opposition to each other by an electrical control input signal, the piston of hydraulic motor 81 can be moved in both directions. The high signal level corresponds to the desired speed. At each connection port side 82, 83 of the hydraulic motor 81, speed adjustment is superposed by pressure adjustment by the pressure control valves 66, 66 '. Similarly, when the piston rod is paid out, the pressure is adjusted by the pressure adjusting valve 67, and thus the force is adjusted in the hydraulic motor 81, and an appropriate correction is taken into consideration.

In the double-acting function controller 80, a differential piston circuit is further obtained. For this purpose, the maximum control input signal controls the pilot valve 39 ', whereby a 3-port continuous valve 1
0'is brought into its operating position 35 ', which connects the annular space 83 to the inflow conduit 46. By the variable control input signal applied to the pilot valve 39, the speed of the piston to be fed can be determined. At that time, the pressure limit and the force limit for speed adjustment are similarly superimposed.

In the case of the fail-safe, the double-acting function control device 80 automatically determines which 3-port continuous valve 10 or 10 'must perform the control function or the replenishment function regardless of the movement direction of the piston rod of the hydraulic motor 81. Understand. In the case of fail-safe, all pilot valves are deenergized by an electric circuit device (not shown), thereby taking their initial positions. Open / close valve
68 assumes its shut-off position, disabling pressure regulating valve 66.
The solenoid valve 49 likewise moves into its initial position, which shuts off the pressure medium supply from the inlet conduit 46 to the control circuits 38, 38 '. Furthermore, the pilot valves 39, 39 'are pushed by their springs into their safe position 55, 55'. Well hydraulic motor 8
It is assumed that the piston rod of 1 carries out a payout movement in advance, and the mass moved thereby tries to maintain this movement in the case of failsafe. As a result, pressure rises in the annular space 83, and at the same time, cavitation occurs in the cylinder space 82. Due to the pressure increase in the annular space 83,
In the effective safety position 55 'of the pilot valve 39', the control circuit 38 'is supplied with control oil via the control conduit 44',
The 3-port continuous valve 10 'acts as a pilot controlled braking pressure valve with the pressure control valve 66' to control the maximum braking pressure, as previously described with reference to FIG. On the other hand, due to the pressure relief in the cylinder space 82 of the hydraulic motor 81, the inlet connection 43 of the pilot valve 39 is no longer supplied with pressure via the branch control conduit 44. Therefore, the pilot valve 39, in its safety position 55, completely removes the pressure from the first control connection 23 of the continuous valve 10 through both throttles 62 and 63 to the tank, so that the spool 12 of the continuous valve 10 is closed. Takes its initial position 34 under the force of the spring 29. Therefore, the piston of the hydraulic motor 81 sucks the pressure medium from the tank conduit 85 via the continuous valve 10 into the cylinder space 82, so that the cavitation is avoided.

When the piston is retracted in the opposite direction of movement of the load in the hydraulic motor 81, this process is correspondingly reversed. The three-port continuous valve 10 then takes on the braking function and the continuous valve 10 ′ makes it possible to replenish the annular space 83 with pressure medium. As a result, in the double-acting function control device 80, it becomes possible to particularly advantageously protect the opposite side against negative pressure in the case of fail-safe braking of the load, while in normal operation, hydraulic pressure with additional pressure adjustment is possible. During the force movement of the motor 81, it is possible to supply sufficient control oil to the control circuits 38, 38 'via the check valves 45, 47, 47' which operate as OR elements.

The control device 90, a part of which is shown in FIG. 4, differs from that according to FIG. 3 only in that the control circuits 38, 38 'are partly changed, whereby an electromagnetically operated pilot-controlled opening / closing valve in the control circuit is provided. Is saved. The same components as in FIG. 3 are again assigned the same reference numerals.

Now, the control valves 44 or 44 'have shuttle valves 91 and 9 respectively.
1'is inserted so that the pressure medium connection is connected to the inlet connection 43, 43 'of the pilot valve 39 or 39'. The two corresponding side connection ports of the shuttle valves 91, 91 'are connected in parallel to the B connection port of the 4-port 4-position switching valve 92. In the initial position of the spring-positioned switching valve 92, this B connection is depressurized to the tank and the control conduit 93 coming from the outlet of the pressure regulating valve 67 is blocked in this position. The switching valve 92 also assumes the crossed position in the demagnetized state of the electromagnet, allowing the supply of control oil from the inlet conduit 46 to the pilot control circuits 38, 38 'via the shuttle valves 91, 91'. At the same time, in this crossed position, the pressure in the control conduit 93 is relieved so that the pressure regulating valve 67 can act.

In this way, the OR function in the control oil supply of the control circuit is maintained, and the functions of the solenoid valve 49 and the opening / closing valve 68 according to FIG. 3 are combined in the single pilot control switching valve 92. Therefore, the solenoid valve is saved as compared to FIG.

It is of course possible to modify the illustrated three-port continuous valve, including its pilot control circuit, without departing from the spirit of the invention. The solution according to FIGS. 2 and 3 for adjusting the braking pressure in the case of fail-safe shows a particularly advantageous design in single-acting or double-acting functions.

[Brief description of drawings]

Fig. 1 is a vertical cross-sectional view of a 3-port continuous valve for block installation,
2 is a connection diagram showing the 3-port continuous valve according to FIG. 1 in a simplified manner together with an attached pilot control circuit, and FIG. 3 has two 3-port continuous valves of FIG. 2 for controlling a double-acting hydraulic motor. FIG. 4 is a connection diagram of the control device, and FIG. 4 is a connection diagram of a part of the control device according to FIG. 3 for different pilot control. 10,10 '…… 3 port continuous valve, 11 …… Housing, 12…
… Spool, 15 …… Inflow port, 16 …… Load port, 17
...... Return connection, 19,28 ...... Pressure surface, 23,26 ...... Control connection

Claims (13)

[Claims] 1. A spool slidably guided in the housing connects the load connection to the inflow connection or the return connection or disconnects both of these connections, the spring and the second pressure. The pressure of the load connection port acting on the surface applies a load in the direction of the initial position excluding the pressure of the load connection port through the return connection port, and the control pressure applied to the first control connection port is reversed in the first direction. In the hydraulic 3-port continuous valve that receives the pressure surface, the first pressure surface (19) is the second pressure surface (28)
Larger, the spool (12) has an additional control edge (27), the housing (11) is provided with a second control connection (26), the control edge (27) being both control connections (23). , 26) Controlling the connection of the hydraulic pressure, 3 port continuous valve for built-in block. 2. The control edge (27) is provided with a precision control recess (30), disconnecting both control connection ports (23, 26) at the initial position (34) of the spool (12), the load connection port. At the operating position (35) connecting (16) to the inflow connection (15) both control connections (23,26) are connected and at the braking position (36) between both positions the inflow While shutting off the connection port (15) and narrowing the connection path between the load connection port (16) and the return connection port (17), the connection of both control connection ports (23, 26) is such that the precision control recess ( 30) The three-port continuous valve according to claim 1, characterized in that it is throttled through. 3. A first pressure surface (19) and a second pressure surface (28).
And the ratio is such that the spool (12) can be moved to a braking position (36) which enables the braking action of the load against the force of its spring (29). The 3-port continuous valve according to claim 1. 4. A spool (12) has a zero position (33) between a braking position (36) and an operating position (35), and at this zero position, an inflow connection port (15) and a load connection port (16). ) And return connection (17) are all blocked and both control connections (2
Claim 2 characterized in that the connection between the (3,26) is made at least via the precision control recess (30).
3 port continuous valve according to the item. 5. A hydraulic pressure control device for controlling a hydraulic pressure controlled to a load has at least one hydraulic 3-port continuous valve (10,1).
0 '), the continuous valve (10, 10') is slidably guided in the housing (11) to connect the load connection port (16) to the inflow connection port (15).
Or a spool (12) that connects to the return connection (17) or disconnects from both connections (15,17) and a spring (29)
And load connection port (16) depending on the pressure of load connection port (16)
Second pressure surface (2) of the spool (12), which is loaded in the direction of the initial position excluding the pressure of the return port through the connection port (17).
8) and a spool that receives a control pressure greater than the second pressure (28) and applied to the first control connection port (23) or the second control connection port (26) in the housing (11) in the opposite direction. An additional control edge of the spool (12) controlling the connection between the first pressure surface (19) of (12) and the first control connection (23) and the second control connection (26) ( 27) and both control connection ports (23, 26) are connected to the motor connection ports (41, 42) of the pilot valve (39) attached to the continuous valve (10), The pressure acting on the first pressure surface (19) has its pressure value limited by the pressure control valve (66) for pilot control, and the inlet connection port (43) of the pilot valve (39).
Can supply control oil from the pilot control circuit (38), and the control member (53) of the pilot valve (39) is the spring (54).
Load is applied to the safety position (55) by means of which the inlet connection port (43) of the pilot valve (39) is connected to the first position.
Is connected to the motor connection port (41) connected to the first control connection port (23) of the continuous valve (10) via the throttle (62) of the continuous valve (10), and via the second throttle (63). At the safety position (55), which is connected to the outflow connection port (51), the flow cross section of the first throttle (62) is larger than the flow cross section of the second throttle (63),
A hydraulic control device, wherein another motor connection port (42) connected to the second control connection port (26) of the continuous valve (10) is connected to the outflow connection port (51). 6. A pilot valve is constituted as a 4-port 4-position switching valve (39) which operates proportionally, and its safety position (55).
Adjacent to the first operating position (57) and the second operating position (5
8) and a third operating position (59) at which the first motor connection port (41) is connected to the inflow connection port (43), is blocked, or is the outflow connection port. (42)
6. The hydraulic control device according to claim 5, characterized in that it is shut off in all operating positions (57-59). 7. A spool (12) of a continuous valve (10) is connected to an electro-mechanical displacement detector (31) and is in a position adjusting circuit (64) with its associated pilot valve (39). The hydraulic control device according to claim 5 or 6. 8. The inlet connection port (43) of the pilot valve (39) is
Through the check valve (45, 47) acting as an OR element, the inflow conduit (46) of the inflow connection port (15) and the load connection port (1)
A hydraulic control device according to one of claims 5 to 7, characterized in that it is connected to the load conduit (48) of 6). 9. The hydraulic pressure control device according to claim 8, wherein the supply of the control oil from the inflow conduit (46) can be shut off by a solenoid valve (49). 10. The pressure at the first motor connection port (41) of the pilot valve (39) is set in parallel to the pressure control valve (66) and is set in the pressure control valve (66). The pressure value is limited by the pressure regulating valve (67) which operates proportionally in the range of pressure value lower than the pressure value, and this pressure regulating valve (67) can be selectively connected by the solenoid valve (68; 92) which is in series. The hydraulic control device according to any one of claims 5 to 9, which is characterized in that there is. 11. A hydraulic control device includes two hydraulic 3-port continuous valves (10, 10 '), a load is a double-acting hydraulic motor (81), and a load of the first continuous valve (10). The connection port (16) is connected to one connection port side (82) of the double-acting hydraulic motor (81), and the other connection port side (83) of this hydraulic motor (81) is a pilot valve (39 '). Pressure control valve controlled by a second continuous valve (10 ') having a pilot control circuit (38') attached to the second continuous valve (10 ') and a check valve (47'). (66 ') is provided, The hydraulic-pressure control apparatus as described in one of Claim 5 thru | or 10 characterized by the above-mentioned. 12. The function of the pressure regulating valve (67) and control oil supply from the inflow conduit (46) can be controlled by a common switching valve (92), and the control conduits (44, 44 ') are respectively shuttle valves. The hydraulic pressure according to claim 11, characterized in that it is connected to the inflow connection port (43, 43 ') of the pilot valve (39, 39') via (91, 91 '). Control device. 13. A flow section which can be opened between both connection ports (23, 26) by means of a precision control recess (30) in the control edge (27) of the spool (17) of the continuous valve (10). Is smaller than the flow cross section of the first throttle (62) in the pilot valve (39), the hydraulic control device according to claim 5.