CN1070974C - Electrohydraulic proportional control valve assemblies - Google Patents

Abstract

An electrohydraulic proportional control valve assembly (1) for controlling a bidirectional fluid actuated device (7) has a first actuating port (4) for bidirectional fluid flow between the assembly and a first port of the device (7), a second actuating port (5) for bidirectional fluid flow between the assembly and a secondport of the device (7), a pump port (15, 16) for input fluid flow from a pump (17), and a tank port (18, 19) for output fluid flow to a tank. The assembly (1) comprises a first spool valve (2) connected to the first actuating port (4), the pump port (15, 16) and the tank port (18, 19) for controlling the direction and rate of fluid flow to and from the first port of the device (7), and a second spool valve (3) connected to the second actuating port (5), the pump port (15, 16) and the tank port (18, 19) and operable independently of the first pool valve 2 for controlling the direction and rate of fluid flow to and from the second port of the device (7). A position sensing arrangement (23, 24) is provided for supplying electrical position signals indicative of the actual positions of the spools (12, 13) of the first and second spool valves (2, 3) and a pressure sensing arrangement (26, 27, 28 and 29) is provided for supplying electrical pressure signals indicative of the fluid pressures in the first and second actuating ports (4, 5), the pump port (15, 16) and the tank port (18, 19). A servo control (not shown) controls the positions of the first and second spools (2, 3) in dependence on the electrical position and pressure signals and in response to an electrical demand signal provided in response to operator actuation, in order to set the throughflow cross sections for fluid flow to effect the required control of the device (7).

Description

Electro-hydraulic proportional control valve assembly

The invention relates to an electro-hydraulic proportional control valve assembly for controlling a hydraulic driving device.

It is known, for example as disclosed in patent document EP-A-0462589, to utilize a proportional control valve assembly to control hydraulic drives. For example, a bulldozer lift arm control lever responds to command signals given by the operator by pushing the joystick. The typical structure of this control valve assembly is that it has a main spool valve with: a first drive liquid flow port, which allows fluid to flow bidirectionally between the slide valve and the first liquid flow port of the hydraulic drive device ; a second drive fluid port for bidirectional fluid flow between the spool valve and the second fluid port of the hydraulic actuator; a fluid inlet for sucking in fluid from the hydraulic pump; and a fluid discharge port for discharging fluid to the tank; and a spool for controlling the direction or rate of fluid flow between the first drive fluid port and the pump port or tank port and between the second drive fluid port and the pump port or tank port The direction or rate of fluid flow between ports.

The control valve assembly may also include a pressure compensator in the form of an auxiliary valve body controlled to maintain a constant pressure drop across the spool of the main spool. This control valve assembly allows the hydraulic drive to be controlled independently of the load. So in the bulldozer lift arm control tie rod example, the arm raises and lowers at a fairly uniform rate regardless of the magnitude of the load being lifted by the arm or the load changing during the lift due to the structure of the arm itself . However, the mechanical structure of this control valve assembly is complicated, which makes manufacturing difficult and increases the cost. In addition, the control function of this control valve assembly is also limited, especially when the direction of the external force exerted on the hydraulic drive due to gravity is the same as that of the moving part of the hydraulic drive under hydraulic control. In an overload condition, the valve may lose control.

International Publication No. WO93/01417 proposes to manufacture a control valve assembly with a reversing valve that includes a position sensor that determines the position of the two drive fluid ports connected to the hydraulic drive. Which one is at high voltage and can send an electrical position signal to the processor to indicate which port is at high voltage. The processor also receives an electrical pressure signal from a pressure transducer to indicate high pressure, and a directional signal to indicate that the operator has moved the spool from neutral to a certain direction via the manual lever. The processor also includes a comparator, the comparator can determine whether the liquid flow input indicated by the directional signal is at high pressure, and output a signal to the positioning device, which is used to control the output of the pump to change according to the comparison result and Vary according to the needs of the load. Although this mechanism uses a special control method to respond to overload conditions, this method only responds to the actual movement of the spool manipulated by the driver, so there is still a risk of loss of control when moving under overload conditions.

It is an object of the present invention to provide a novel proportional control valve assembly which can be manufactured in a clear and simple manner and which can provide a large number of control functions.

The invention provides an electro-hydraulic proportional control valve assembly.

According to the detected position of the valve element, the pressure of the liquid flow port and the pump pressure, and the response to the command signal issued by the operator (such as the signal generated by the driver pushing the joystick), the control valve assembly responds to two The position of each valve element is adjusted to control the fluid flow rate and/or pressure at the fluid port of a hydraulic drive device (such as a hydraulic cylinder or a hydraulic motor). The valve element is continuously controlled by the servo control device according to the constantly changing operating signal that moves the valve element to a position corresponding to a certain flow section, which can be matched with the required flow and pressure conditions and hydraulic drive. suitable for the desired mode of operation of the device. A large number of control functions can be realized through proper planning and arrangement of the control circuit. For example, controlling the fluid flow rate and pressure at the fluid port of a hydraulically driven device allows the device to be adjusted to work at a uniform rate regardless of load. That is to say, the rate of movement of the moving parts of the device will be independent of changes in applied load and supply pressure, whether under passive load conditions or overloaded operating conditions. In addition, servo control of valve element position controlled by feedback position signals ensures highly accurate valve element positioning without detailed analysis of valve characteristics or adjustments to account for wear.

In the solution with two separate valve devices, there are valve elements that can move separately, which has the advantage that the first and second drive fluid ports can be staggered to open and close so as to realize the control of the hydraulic drive device. Independent control of the fluid flow rate and pressure at the two fluid ports of the hydraulic drive unit with this valve assembly makes it possible to make the unit more efficient and safer to operate than the aforementioned control scheme due to the aforementioned The moving parts of the device in the solution need to move against the back pressure causing efficiency loss. In addition, in the event of pressure overload, such as when the movement of moving parts of the unit is blocked by an external overload load or where free floating of the load is required, one or both valve elements may be opened to the tank in order to connect the hydraulically driven unit to both sides of the unit. The side streams are discharged separately or simultaneously.

In order that the present invention may be more fully understood, a preferred example of a control valve assembly according to the present invention will be described by way of example with reference to the accompanying drawings. in:

Fig. 1 is a hydraulic circuit diagram of the electro-hydraulic proportional control valve assembly of the present invention;

Fig. 2 is a schematic cross-sectional view of a certain part of the assembly;

Figure 3 is a block diagram showing the electrical connections between the various parts of the assembly; and

Figure 4 is a logic diagram illustrating the assembly control functions.

The electro-hydraulic proportional control valve assembly 1 shown in Fig. 1 includes first and second slide valves 2 and 3, and first and second drive liquid flow ports 4 of a hydraulic drive device 7 in the form of a hydraulic cylinder or a hydraulic motor It is connected with 5 and is used to control the liquid flow on opposite sides of the movable piston 6. The first and second spool valves 2 and 3 have spools 12 and 13 which are axially movable under the action of a control fluid flow. The flow is controlled between their extreme positions by electrically operated pilot control valves 44 and 45 (the valves will be described in more detail later with reference to FIG. 2 ). The outer spool 12 or 13 in the limit position connects the corresponding liquid flow port 4 or 5 with the pump port 15 or 16, and the pump port 15 or 16 communicates with the output port of the pump 17 or the fuel tank port 18 or 19 connected with the fuel tank 20 . Liquid delivery to pilot control valves 44 and 45 is regulated by control pressure regulator 14 .

The spool 12 or 13 of each slide valve 2 or 3 passes through a flow cross section to realize the opening of the slide valve 2 or 3 to the pump port 15 or 16 or to the tank port 18 or 19 . The cross section varies proportionally with the position of the spool 12 or 13 between a minimum opening value and a maximum opening value. In addition, both spools 12 and 13 are biased toward their neutral position (as shown in FIG. 1 ) by springs, and position sensors 23 and 24 are used to generate electrical position signals to indicate the position of spools 12 and 13 . In addition, the pressure relief valve 25 is used to discharge the output of the pump 17 directly into the oil tank 20, and its discharge method will be described in detail later. Four pressure transducers 26, 27, 28 and 29 are used to generate electrical pressure signals _PA , _PB , _PS and _PT which are shown at the first and second liquid flow ports 4 and 5, pump port Fluid pressure at 15 or 16 and tank port 18 or 19.

As schematically shown on the right side of Figure 1, the control pressure regulator 14 can also be used to adjust the control fluid flow supplied to the pilot control valve of another pair of spool valves that is the same as the spool valves 2 and 3, thereby controlling the supply to another hydraulic drive device 30 flow. These two devices 7 and 30 may be two pull rods used to control, for example, different connecting shafts of a bulldozer, and may be controlled by two valve slices in the device, which will be described in more detail below instruction of.

FIG. 2 shows a section through the section of the valve plate comprising one of the first and second spool valves 2 and 3 and the associated one of the pilot control valves 44 and 45 . There are both parts in every valve section. The pilot control valve 44 or 45 has a moving coil 35 secured to a control spool 36 which is kept centered by two springs 37 and 38 . The coil 35 can move in the annular air gap 39 inside the forming magnet 40. This movement will occur when the magnetic field generated by the current passing through the coil 35 and the magnetic flux generated by the forming magnet 40 in the air gap 39 interact with each other. . The pilot control valve 44 or 45 has two driving liquid flow ports 46 and 47 respectively connected to both ends of the slide valve 2 or 3 through passages 48 and 49, the valve 44 also has a fuel tank port 70 connected to the fuel tank and two pump ports 71 and 72 is connected to the pump either directly or via the control pressure regulator 14. The spool 12 or 13 of the spool valve 2 or 3 is kept in the center under the action of the springs 73 and 74, and one end of the spool has an extension 75, which can pass the position feedback signal according to the position of the spool 12 and 13 through the position sensor 23 or 24 outputs.

When the spool 36 of the pilot control valve 44 or 45 is in the neutral position as shown in Figure 2, only a small amount of leakage liquid passes through the pilot control valve, so the spool 12 or 13 of the main spool valve 2 or 3 is also shown in the figure Shown by the springs 73 and 74 to keep it in the neutral position. When a position control current is sent to the coil 35, a force is applied to the spool 36, causing it to move in a certain direction (depending on the direction of the current) until a certain equilibrium position is reached, where the force is The active forces of springs 37 and 38 are balanced. If the spool 36 moves to the right as shown in the figure, a passage is opened between the pump port 71 and the liquid flow port 46 and between the fuel tank port 70 and the liquid flow port 47, and the size of the flow section is determined by the size of the current. Decide. As a result, the control liquid is controlled to flow along the channel 48 to the left end of the spool 12 or 13 of the main spool valve 2 or 3, while the control liquid flow is controlled to discharge into the oil tank from the right end of the spool 12 or 13 through the channel 49. This process causes the main spool 12 or 13 to be pushed to the right as shown in the figure, and its moving speed is determined by the opening degree of the pilot control valve 44 or 45 until the position feedback signal output by the position sensor 23 or 24 shows that the valve The spool has been pushed to the desired position, the current to the coil 35 is cut off and the spool 36 of the pilot control valve 44 or 45 returns to its neutral position under the action of the springs 37 and 38. Thus, the main spool 12 or 13 stops moving and is held in the required position, which is achieved by the hydraulic pressure acting on both ends of the spool.

In fact, the pilot control valve current is controlled by the control circuit in a complex way in order to achieve the best dynamic and position control characteristics, that is, to quickly push the main spool 12 or 13 to the required position, and make the valve The column remains exactly in this position for as long as necessary. In practice, even if movement of the main spool 12 or 13 is not necessary, it may be necessary to energize the coil 35 with a small current under servo control in order to provide a small flow through the pilot control valve 44 or 45 to compensate for liquid leakage, This keeps the main spool 12 or 13 in the pushed position. However, the current required to maintain the position of the main spool will be so small that it will not adversely affect the normal low current compensation of the control circuit. The control circuit accurately monitors the position of the main spool 12 or 13 at all times through the position sensor 23 or 24, and continuously controls the current to the coil 35 to provide the necessary feedback control of the main spool position.

Because the structure of the spool 36 and the moving coil 35 fixed on the spool 36 is very light, the energy consumption is very small, so the control circuit only needs to consume very little electric energy, and the cost of parts is also low. In addition, it is possible to move the spool 36 at a higher speed to react quickly to the applied current under servo control. Under the influence of the reverse current in the coil 35, the spool will move rapidly in reverse. This not only provides rapid control of the supply from the pump to the main spool 12 or 13 and the corresponding discharge from the main spool to the tank, thereby providing precise dynamic control of the position of the main spool in response to the position feedback signal, but also to the Control of the piston 6 of the hydraulic drive 7 is also possible with sufficient response time for good control of the load. This control mode is not possible with previously known control methods. For example, when the movement of the load is hindered, such as when the bucket of the excavator hits an obstacle, one of the pressure sensors 26 and 27 senses the pressure overload and triggers a corresponding pressure relief signal, so that the corresponding pilot control valve 44 or 45 operates so that one of the main spools 12 and 13 is opened rapidly to communicate with the oil tank. This method is adopted to reduce the pressure in the hydraulic drive unit and avoid damage caused by overload. Due to the high-speed dynamic response of the pilot control valve, this relief usually occurs very quickly. Other control characteristics exhibited by the high speed dynamic response of the pilot control valves 44 and 45 under servo control are discussed below.

Fig. 3 shows the complete control valve assembly of this kind, for example, it comprises, a set of two valve plates 50 and 51 of the general type described, each having a first drive liquid flow port 4 and a second drive liquid flow port Port 5 is used to be connected with the corresponding hydraulic drive device (shown in the figure); the end piece 52 connected with the valve pieces 50 and 51 has a pump port 53 and a fuel tank port 54 . The end piece 52 controls the hydraulic fluid pressure delivered from a quantitative pump (not shown) connected to the pump port 53 according to the command signal for supplying fluid to the valve sections 50 and 51, so as to ensure that the fluid is only supplied when needed. , and if the valve plates 50 and 51 do not need to supply hydraulic fluid for a while, it can ensure that the pump is in an idle state. When the driver operates, the pressure relief valve 25 shown in FIG. 1 is controlled according to the load detected by the pressure sensors 26 and 27, and is used to control the liquid pressure supplied by the pump to be higher than the maximum load pressure by a certain amount. When no load pressure is detected, the pressure relief valve 25 returns fluid to tank at normal low pressure. When replacing a method with a variable displacement pump, the valve 25 can be set to control the displacement of the pump in a manner that ensures liquid supply according to the needs of the system. Although FIG. 3 shows only two valve sections 50 and 51 for simplicity, it is understood that in actual use a set of four to ten valve sections may be used.

In addition, a control computer 55 is connected with the valve plates 50 and 51 and the joystick 56 through a series of communication networks, so as to monitor the driver's manipulation and provide pressure (P) or flow rate (Q) to the valve plates 50 and 51. ) Command signal and pressure-flow (P-Q) selection signal. In addition, the control computer 55 can be used to provide initial setting data to the valve sections 50 and 51 and use the plug-in programmer 57 to perform initial setting programming, and can also provide error monitoring for the valve sections 50 and 51 . Provision may be made, if desired, for the temporary connection of a means of plug-in actuator 58 to the valve sections 50 and 51 for emergency operation of the valve sections. If desired, a working condition monitoring display 59 can also be connected to the control unit 55 to display the correct working condition of the valve plates 50 and 51.

The method of utilizing the control computer 55 to control the valve plates 50 and 51 so as to realize the necessary control of the hydraulic drive device will now be briefly described with reference to FIG. It is contained within the valve plates 50 and 51 rather than the computer 55 which is used to provide control of the overall system. The control computer 55 provides a pressure-flow (P-Q) selection signal for each valve section, and the selector in each valve section makes a selection according to the signal to realize pressure control or flow control.

It can be understood with reference to FIG. 4 that in this particular control mode, the control of the hydraulic drive is provided by the computer in accordance with the operator's command signals to the control lever and/or control mode selector button or switch The signal type is selected to determine, as shown in the control mode iteration loop 80 in the figure. If flow control mode is selected, a flow demand signal Q _DEM is sent to selector 81 which determines the desired direction of flow to the hydraulic drive, ie to port A or port B. In the event that flow is not desired, the control acts to keep both main spools in their neutral positions. In the event that port A requires flow, another selector 82 will determine whether the pressure at port A is greater or less than the pressure at port B, ie the load is considered passive or excessive. In the case of a passive load, the flow section a of the spool valve required to control the flow to port A is calculated at 83, that is, the flow demand signal Q _DEM is valued $\sqrt{P_S-P_A}$ Divide and multiply by a constant of proportionality. The rated downstream back pressure acting on port B is set at 84, and the position required for both spools is controlled at 85 with the control signal sent to the pilot control valve of the upstream spool valve to set the flow through section a ． In addition, the downstream back pressure is set at a predetermined level by providing a control signal to the pilot control valve of the downstream spool valve.

If an overload condition occurs, the flow cross-section a of the spool valve required to control the flow to port B is calculated at 86, i.e. the flow demand signal Q _DEM is numerically $\sqrt{P_B-P_T}$ Divided and multiplied by a proportionality constant (where _PT is the sensed tank pressure or the pressure set if there is no tank sensor), the control of filling the upstream side of the piston of the hydraulic drive through port A is at It is set at 87, so that the control of the required positions of the two spools at 88 is provided by the appropriate setting of the flow cross-section a of the downstream valve to provide metering control of the liquid flowing out of port B and the control of the flow of the upstream valve Liquid charge control through port A under control. Since the pilot actuator valve has the ability to switch quickly from supplying fluid to the main spool valve in one direction to supplying fluid in the opposite direction, this control arrangement can discontinuously switch from a passive load state to an overload state, because when the bulldozer The lifting arm is raised by the hydraulic drive to pass through an over-center position, so that the force of gravity acting on the load is in the same direction as the piston movement, rather than in the opposite direction before the over-center position is reached. The construction of the fuel tank sensor allows for more accurate control in the event of an overload situation, thereby avoiding any discontinuity of control.

If the liquid flow demand direction determined by the selector 81 is sent to the liquid flow port B of the hydraulic drive device, then a series of similar control steps will be carried out. These steps have been described, and the difference is about port A and port A. The control of B should be reversed, so the measured pressure signal P _B should be used instead of _PA when calculating, and vice versa. In each case the spool position is continuously monitored by the position transducer and the signal to the pilot control valve is varied as required with the position feedback signal from the position transducer.

If pressure control is selected, the pressure applied to the ports A and B of the hydraulic drive is controlled by the operator by pulling the joystick. The movement of the joystick determines the rate of change (magnitude and direction) of the pressure acting on the load. If the movement of the joystick stops, no further pressure changes are applied to the load. The initial pressure demand is calculated at 89 using the input signal from the joystick. The selector 90 will then determine whether the pressure required by the pressure demand is applied at port A or port B. If the pressure demand is zero, set the pressure at both ports to a nominal value. If the pressure demand requires pressure to be applied to port A, the selector 91 will first determine whether there is a surge pressure applied to the piston, for example in order to vibrate the load when the ramming (compacting) mode is selected. According to the result of this selection, the required pressure at port A is set as the required pressure in step 92, and the pressure at port B is set as the rated value, and the required control signal is sent to the pilot of the two spool valves in step 93. Control the valve to incrementally control the position of the main spool to set the required pressure at ports A and B based on the position feedback signal.

If the pressure demand requires pressure to be applied to port B, a similar control step will be performed sequentially, but with the demand pressure applied to port B and the pressure at port A set to a nominal value, that is, a predetermined pressure, which Above measured or set tank pressure. If Ramping mode is selected, a demand pressure that varies periodically with a sine wave is superimposed on the base demand pressure, and the load is vibrated by the resultant pressure.

The pressure control mode can be beneficial under various operating conditions. For example, when lifting a load, the initial pressure control mode performs continuous pressure balancing on the load, so that the load can be manually manipulated with only a small pressure. Furthermore, if the load is, for example, an excavator arm with a bucket for excavating earth, its exerted pressure can be controlled, and if the bucket hits an obstacle, such as a buried object, a predetermined pressure limit The value will not be exceeded, so there is no risk of damage to buried objects due to excessive pressure applied.

If the operator selects the float mode by manipulating a special switch, the two main spools are controlled at step 94 to open both sides of the piston of the hydraulic drive to the tank so that the piston and any associated The movement of the load can float freely.

When the above-mentioned valve assembly adopts the first and second spool valves 2 and 3 to control the inflow and outflow of the hydraulic drive device fluid flow, there is another valve assembly according to the present invention but not shown in the drawings. Use, that is, use a pair of poppet valves instead of each slide valve to separately control the flow of liquid from the pump to the device through the associated drive fluid port and the flow of liquid from the device to the tank. In each case, the pair of poppet valves associated with each associated fluid port are controlled by pilot control valves to provide the required fluid flow in various control modes. Additionally, each pilot control valve itself may contain a pair of poppet valves to control the flow of fluid into and out of the main valve or other valves in response to the current action of the moving coil.

Claims (14)

1. an electrohydraulic proportional control valve assemblies (1), can be used to control two-way function fluid pressure drive device (7), this device has the first and second liquid head pieces and the movement parts (6) between first and second mouthfuls, the effect that the relative both sides of this movement parts are subjected to supplying with the fluid of the first liquid head piece and supply with the fluid of the second liquid head piece, this valve assembly comprises: one first drives liquid head piece (4), can do two-way flow between valve assembly and fluid pressure drive device (7) first mouthful by this mouthful liquid; One second drives liquid head piece (5), can do two-way flow between valve assembly and fluid pressure drive device (7) second mouthful by this mouthful liquid; Logical pumping hole (15,16) is used for liquid stream is input to valve assembly from hydraulic pump (17); Logical reservoir port (18,19), be used for liquid stream is outputed to fuel tank (20) from valve assembly, this valve assembly also comprises: drive first valving (2) that liquid head piece (4), pumping hole (15) and reservoir port (18) are connected with first, be used for controlling first and drive between liquid head piece (4) and the pumping hole (15) and liquid flows between the first driving liquid head piece (4) and the reservoir port (18) direction and speed; With the second driving liquid head piece (5), second valving (3) that pumping hole (16) and reservoir port (19) are connected, being used for controlling second drives between liquid head piece (5) and the pumping hole (16) and liquid flows between the second driving liquid head piece (5) and the reservoir port (19) direction and speed, first valving (2) has movably first valve element (12), it can change first passage section that drives between liquid head piece (4) and pumping hole or the reservoir port (15 or 18), second valving (3) has one movably and second valve element (13) relatively independent with the motion of first valve element (12), it can change second and drive passage section between liquid head piece (5) and pumping hole or the reservoir port (16 or 19)

It is characterized in that, also comprise: position detecting device (23,24) is used to provide the electric position signal to show the physical location of first and second valve elements (12 and 13); Pressure-detecting device (26,27 and 28) is used to provide the fluid pressure of voltage signal to show that first and second liquid head pieces (4 and 5) and pumping hole (15,16) are located; And Servocontrol device, be used for controlling the position of first and second valve elements (12 and 13) and reacting to being used for the electric desired signal of mirror operation person's action according to electric position and voltage force signal, so that be set in first drive between liquid head piece (4) and pumping hole or the reservoir port (15 or 18) and second passage section that passes first and second valvings (2 and 3) that drives between liquid head piece (5) and pumping hole or the reservoir port (16 or 19), thereby the movement parts (6) of fluid pressure drive device (7) is carried out the control of needs.

2. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that first and second valve elements (12 and 13) are valve rod, they can move axially to change the passage section between each driving liquid head piece and pumping hole or the reservoir port.

3. according to claim 1 or 2 described electrohydraulic proportional control valve assemblies, it is characterized in that, Servocontrol device comprises and is used for controlling each valve element (12,13) electricity of position operation pilot valve device (44,45), this Position Control is to deliver to a part of valve element by the controlled volume stream that will control liquid, meanwhile realize the controlled discharge of control liquid from another part of valve element, so that fully promote valve element to the desired position of first operational mode, then disconnect described control liquid capacity stream and the described control fluid discharge of delivering to valve element, so that make valve element remain on the desired position of described second operational mode.

4. according to the described electrohydraulic proportional control valve assemblies of claim 3, it is characterized in that, the pilot valve device comprises first pilot valve (44) that is used for realizing the motion of first valve element (12) bi-directional axial, and second pilot valve (45) that is used for realizing with relatively independent second valve element (13) the bi-directional axial motion of the motion of first valve element (12).

5. according to the described electrohydraulic proportional control valve assemblies of claim 4, it is characterized in that, each pilot valve comprise one when feeding drive current can with the relatively-movable drive coil of moulding magnet (40) (35), movably valve element (36) by coil drive, this element can be controlled simultaneously to the part input control liquid of described valve element and from another part of described valve element and discharge control liquid.

6. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that, Servocontrol device is exercisable, in pressure control mode, it controls the position of first and second valve elements (12 and 13), and the voltage power desired signal that the operator sends is reacted corresponding to the load pressure of needs, also control the fluid discharge that drives liquid head piece (5 or 4) from another so that drive liquid head piece (4 or 5) input controlled stream, thereby produce a pressure differential that strides across fluid pressure drive device (7) corresponding to the load pressure of needs to one.

7. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that, Servocontrol device is exercisable, in floating mode, it controls the position of first and second valve elements (12 and 13), the unsteady desired signal of electricity that the operator sends is reacted, so that from two liquid head pieces (4 and 5) discharging fluid stream, thereby the freedom of motion of the load that permission is connected with fluid pressure drive device floats.

8. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that, Servocontrol device is exercisable, in ramming pattern, it controls the position of first and second valve elements (12 and 13), the electrorammer that the operator is sent hits signal and reacts, so as fast repeatedly conversion lead to the liquid flow path direction that drives liquid head piece (4 and 5), thereby the load that will be connected with fluid pressure drive device (7) is vibrated.

9. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that, Servocontrol device is exercisable, in unloading die pressing type, it controls the position of first and second valve elements (12 and 13), to pressure-detecting device (26,27) one drives liquid head piece (4,5) the detected overload pressure in place touches electricity release signal and reacts, so that discharge controlled fluid from a described fluid port, thus release.

10. according to the described electrohydraulic proportional control valve assemblies of claim 1, it is characterized in that pressure-detecting device comprises: one is used to provide the first voltage force signal to show that first drives first pressure sensor (26) that liquid head piece (4) is located fluid pressure; One is used to provide the second voltage force signal to show that second drives second pressure sensor (27) that liquid head piece (5) is located fluid pressure; One is used to provide the tertiary voltage force signal to show the 3rd pressure sensor (28) of pumping hole (15,16) fluid pressure; And one be used to provide the 4th voltage force signal to show logical reservoir port (18,19) the 4th pressure sensor (29) of fluid pressure, and watching controlled device is the position of controlling first and second valve elements (12,13) according to the first, second, third and the 4th voltage force signal.

11., it is characterized in that a control computer (55) is used to monitor electric desired signal that the operator sends and according to this desired signal the repertoire of Servocontrol device is controlled according to the described electrohydraulic proportional control valve assemblies of claim 1.

12., it is characterized in that according to the described electrohydraulic proportional control valve assemblies of claim 1, adopted modular organization, comprise that an assembling fits over valve block together, and be used to control some fluid pressure drive devices.

13. an electric-hydraulic proportion valve assembly (1) that is used for controlling fluid pressure drive device (7) has on it: drive liquid head piece (4,5), be used between this valve assembly and fluid pressure drive device, flowing by liquid; Logical pumping hole (15,16) is used for from hydraulic pump (17) to valve assembly input liquid stream; Logical reservoir port (18,19) is used for from valve assembly liquid stream being outputed to fuel tank (20); And valving (2,3), be used for controlling driving liquid head piece (4,5) with pumping hole (15,16) between and liquid head piece (4,5) and reservoir port (18,19) direction and the speed of liquid stream between, this valving comprise at least one movably valve element (12,13) be used for changing passage section between liquid head piece and pumping hole or the reservoir port

It is characterized in that this valve assembly also comprises: first pressure-detecting device (26,27) is used for producing representative and drives the first voltage force signal that liquid head piece (4,5) is located fluid pressure; Second pressure-detecting device (28) is used for producing the second voltage force signal that the logical pumping hole (15,16) of representative is located fluid pressure; Servocontrol device, go to control the position of at least one described valve element according to the voltage force signal, and the electric desired signal of mirror operation person action reacted, so that set by being in the passage section of the valve assembly between liquid head piece and pumping hole or the reservoir port, thereby fluid pressure drive device is carried out the control of needs, Servocontrol device also comprises electric exercisable pilot valve device (44,45), flow to valve element by the controlled volume of importing control liquid and control at least one described valve element (12,13) position, with abundant promotion valve element to the desired position of first operational mode, disconnect the described control liquid capacity stream of delivering to valve element subsequently again, valve element is remained on the desired position of described second operational mode.

14. according to the described electrohydraulic proportional control valve assemblies of claim 13, it is characterized in that, this control valve assembly also comprises: the 3rd pressure-detecting device (29), be used for producing the tertiary voltage force signal to show reservoir port (18,19) fluid pressure, wherein Servocontrol device can be according to first, second and the tertiary voltage force signal remove to control at least one described valve element (12,13) position, and the electric desired signal of mirror operation person action reacted, so that set by being in the passage section of the valve assembly between liquid head piece and pumping hole or the reservoir port, thereby realize fluid pressure drive device is carried out the control that needs.

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