EP2642132B1 - Hydraulic valve assembly with hydraulic pilot valve assembly - Google Patents

Description

The invention relates to a hydraulic valve arrangement according to the preamble of patent claim 1.

According to the prior art, a pressure medium volume flow can be controlled in a conventional manner via a continuously variable proportional directional control valve with n connections and m switching positions. However, this conventional analog control of the pressure medium volume flow brings considerable device and control engineering expenses with it.

Device and control simplifications allow the application of digital hydraulic concepts. Each control edge of a conventional proportional directional valve is dissolved via at least one valve with at least one basic and one switching position. In order to obtain the finest possible pressure medium volume control per control edge, however, this control edge is preferably dissolved in more than one, for example in four or five, switching valves, wherein a ratio of the respective nominal values based on the smallest of the switching valves, for example 2, 4, 8, 16 , ... is. A valve with four control edges is thus replaceable over at least four switching valves. If one considers a control edge and assumes that four switching valves with a nominal size of 1, 2, 4 and 8 are provided for this control edge, the result is an exponential change of the nominal quantities of a number of 2 ⁴ possible volume flow variables. A disadvantage of this so-called pulse-coded modulation (PCM), however, is that a finer control of the pressure medium volume flow can only be achieved over a larger number of valves, which means a high device complexity.

In order to fine tune the volume flow and to allow volume flows smaller than that of the smallest valve of the arrangement, the concept of pulse width modulation (PWM) can be used. In this case, a nominal volume flow of the thus controlled valves can be reduced in that the actuating element of the valve is not continuous but only approximately in the time frame of a pulse or its pulse duration is turned on or fully open. After the pulse duration, there is a pulse pause in which the valve falls from its switching position to the basic position. About a ratio of the pulse duration to the sum of pulse duration and pulse pause, the duty cycle, the size of the pressure medium volume flow can be adjusted. In this way, a comparatively fine adjustment of the pressure medium volume flow is already possible. From the DE 10 2009 052285 A1 is a balancing valve is known that behaves ballistically.

The European patent EP 0 828 946 B1 shows to a pilot valve assembly with a four-way valves having bridge circuit, wherein a valve body of a proportional directional control valve is hydraulically clamped in a first diagonal or in a bridge of the bridge circuit. A pressure medium input of a second diagonal of the bridge circuit is connected to a pressure medium source and a pressure medium output of the second diagonal with a pressure medium sink. Each switching valve has a basic position and a switching position and is for controlling a pressure medium volume flow of the pilot valve arrangement pulse width modulated electromagnetically actuated.

A disadvantage of this solution is that a large number of switching valves of different nominal size would still be required for a required large bandwidth of the pressure medium volume flow. Alternatively, although a very fast switching switching valve large nominal diameter could be used, but this is expensive. However, the switching speed can not be increased arbitrarily and also subject to the switching valve due to the fast switching an increased risk of wear.

On the other hand, the invention is based on the object to provide a hydraulic valve assembly with a vorzusteuernden valve in which compared to the prior art with the same or lower device complexity, a pressure medium flow rate for pilot control of the valve is finer controllable.

This object is achieved by a hydraulic valve arrangement having the features of patent claim 1.

Advantageous developments of the invention are described in the dependent claims 2 to 13.

A hydraulic valve arrangement has at least one pilot valve arrangement and, in addition, at least one valve which can be precontrolled via the pilot valve arrangement. The pilot hydraulic valve arrangement for precontrol of the, in particular hydraulic, valve has at least one or a first pulse width modulated actuatable pilot valve, and has a high pressure port for connection to a pressure medium source, a low pressure port for connection to a pressure sink and a first control port for connection to a first Control chamber of the valve to be controlled. In this case, the first control connection of the pilot valve arrangement is connected to the first control chamber of the valve to be controlled or at least connectable. By way of an open position of the first pilot valve, the first control connection can be connected to the high-pressure connection or to the low-pressure connection. According to the invention, the first pilot valve is ballistically actuated.

Compared to the state of the art, due to the advantages associated with the ballistic actuation of the first pilot valve, a device-type simplified hydraulic valve arrangement is provided, by means of which, moreover, a pressure medium volume flow for precontrol of the valve can be controlled more finely.

The term "ballistic" encompasses ballistic and, alternatively, inverse ballistic activity. For a detailed description of the ballistic activity, reference should be made here to the publication " A Novel Model For Optimized Development And Application Of Switching Valves In Closed Loop Control "(International Journal of Fluid Power 12, 2011, No. 3 ) of the Applicant. Because of this ballistic actuation, the first pilot valve can assume intermediate positions (partial openings) which have an opening cross section which is smaller than a maximum open position and greater than a closed position of the first pilot valve. An electromagnetic actuating element of the first pilot valve, for example an armature of an electromagnet, can either be de-energized or energized in a basic position. The The basic position of the pilot valve may be a flow position or a blocking position, or vice versa. The basic position is preferably spring-biased. If one considers the basic position and the switching position of the first pilot valve as a bit with the values zero or one, then this bit is "divisible" via the principle of ballistic actuation. The often considered a disadvantage of digital hydraulic fact that the switching elements are mass and sluggish, and thus no unique binary behavior is possible, now allows the inventive combination with the ballistic actuation a device technically less complex and fine pressure medium volume flow setting. Compared to the conventional pulse width modulation in which the first pilot valve with each actuation pulse completely thrown into the switching position and thrown back in the following pulse break in the normal position, there is the advantage of a particularly fine pressure medium volume control. Compared to a conventional device-technically complex and difficult-to-control proportional directional control valve can be used with the aid of the ballistic actuation according to the invention, for example, a device simpler ausgestaltetes valve (switching valve or directional control valve). In addition, unlike a conventional pulse width modulated valve, this valve does not have to have a very short switching time. This allows the use of a switching valve of large size and volume flow bandwidth.

For ballistic actuation, it applies that a pulse duration t _{i of} a ballistic actuation pulse of the at least one pilot valve is greater than a minimum pulse duration t _{i, min of} the at least one pilot valve, starting from a throw of a valve body of the at least one pilot valve out of its basic position in the direction a switching position takes place. In addition, the pulse duration t _{i is} so small that no complete throw of the valve body takes place up to the switching position. In the case of inverse ballistic actuation, the pulse duration t _{i of} the actuating pulse of the first pilot valve is at least so great that a complete throw of the valve body of the first pilot valve into its switching position takes place. A following the actuation pulse pause duration t _p, in which no actuation pulse is present, is less than a minimum pause duration t _{p, min,} which is necessary for a complete discarding or relapse of the valve body is in its basic position into it. The valve body is thus again thrown by a renewed actuation pulse in the direction of the switching position before it reaches its basic position. The pulse duration t _i is preferably between 2 and 3 ms and is shorter than a switching delay time of the first pilot valve, for example 7 ms. Preferably, the first pilot valve is such configured to have a switching time t _s for switching into the switching position of about 7 ms and a switching delay time t _{i, min} of about 2 ms. Of course, the pulse duration t _{i can} also assume values equal to or greater than the switching time t _s , so that the switching position is switched through after the switching time t _s at least for the rest of the pulse duration t _i . Preferably, a fundamental frequency of the pulse width modulation is smaller than a maximum switching frequency of the first pilot valve. Particularly preferably, the fundamental frequency is about 0.5 to 1.0 times the maximum switching frequency. The stated preferred values of the variables t _i, t _{mins i,} t _p, t _{p, min} and their relations with each other are in the following description preferred for all ballistic operated pilot valves.

A preferred variant of the hydraulic pilot valve arrangement of the valve arrangement has a second pilot valve which is connected in series with the first pilot valve in a pressure medium flow path from the high-pressure port to the low-pressure port. In this case, the first or the second pilot valve is arranged in a pressure medium flow path from the high pressure port to the first control port and the other of these two pilot valves, ie the second or the first, is arranged in a pressure fluid flow path from the first control port to the low pressure port. In this way, in each case a pressure medium volume flow from the high-pressure connection to the low-pressure connection, from the high-pressure connection to the first control connection or first control chamber of the valve to be controlled and from this to the low-pressure connection can be set. Particularly preferably, the second pilot valve is electromagnetically pulse width modulated ballistically actuated.

A preferred development of the hydraulic pilot valve arrangement of the valve arrangement has a second control connection for connection to a second control chamber of the valve to be controlled. In this way, by simply acting on the respective control connection, a valve body of the valve to be controlled can be moved or thrown in opposite directions.

A particularly preferred development of the hydraulic pilot valve arrangement of the valve arrangement has a third and a fourth pilot valve. These two pilot valves are connected in series in a pressure fluid flow path from the high pressure port to the low pressure port. Furthermore, the third or the fourth pilot valve in a pressure fluid flow path from the high pressure port to the second control port and the other of these two pilot valves, that is, the fourth or third, is arranged in a pressure fluid flow path from the second control port to the low pressure port. This construction of the hydraulic pilot valve arrangement corresponds to a bridge circuit with two diagonals, wherein a first diagonal is formed via the first and the second control connection and a second diagonal via the high-pressure and the low-pressure connection. In this way, via the pilot valve arrangement, in each case a pressure medium volume flow from the high-pressure connection to the low-pressure connection, from the high-pressure connection to the second control connection or second control chamber of the valve to be controlled and from this to the low-pressure connection can be set. With particular preference, at least the third or fourth pilot valve can also be activated by electromagnetic pulse width modulated ballistics. Particularly preferred are both.

In a particularly advantageous development of the hydraulic pilot valve arrangement of the valve arrangement, at least the first pilot valve is designed as a 2/2 switching valve. This means that under nominal conditions a force, in particular a spring force, which biases a valve body, in particular a valve spool or valve piston, of the switching valve into a basic position, is small compared with an actuating force of the switching valve resulting from the actuating pulse. Therefore, a switching valve can be switched very quickly after application of the actuating pulse in the switching position. For further developments with two, three or four pilot valves, at least one of these further pilot valves is preferably designed as a 2/2 switching valve. Particularly preferably, all pilot valves are configured in this way. The basic position of the pilot valve (s) may be an open cross-sectional flow position or a shut-off restricted position, or vice versa.

In an alternative variant of the hydraulic pilot valve arrangement of the valve arrangement, the first pilot valve is a directional control valve which has at least three connections: the high-pressure connection, the low-pressure connection and the first control connection. The directional control valve is preferably configured such that the first control connection connects the first control connection to the high-pressure connection or to the low-pressure connection. Preferably, the directional control valve is a 3/3-way valve.

In order to be able to control the second control chamber of the valve to be controlled via the directional control valve, the hydraulic pilot valve arrangement of the valve arrangement also has the second control connection in an advantageous development. Then the directional control valve is preferably designed as a 4/3-way valve.

In a preferred embodiment of the valve arrangement, at least the first and / or second and / or third and / or fourth pilot valve is designed as a seat valve or as a slide valve.

The inventive hydraulic pilot valve arrangement of the valve assembly also has a control unit which is designed such that it is at least the first of the pilot valves electromagnetically pulse width modulated ballistically actuated. Preferably, via the control unit, a multiple or multiplicity of pilot valves, in particular all pilot valves, are actuated by means of electromagnetic pulse width modulated ballistics.

It should be emphasized that the pilot valve arrangement of the valve arrangement can also have more than four, for example five, six, seven or eight, or more, pilot valves as described above.

A preferred variant of the hydraulic valve arrangement has a pilot valve arrangement, which also has the above-described second control connection, which is connectable, in particular connected, to a second control chamber of the valve to be controlled.

In an alternative variant of the hydraulic valve arrangement, the first control chamber of the valve to be controlled is limited at least in sections via a first control surface of a valve body of the valve to be controlled and a second control chamber of the vorzusteuernden valve at least partially via a second, the first counteracting control surface of the valve body. In this case, the second control chamber can be connected to a connection of essentially constant pressure, in particular connected.

In a preferred development of this variant, the second control chamber of the valve to be controlled is connectable, in particular connected, to the high-pressure connection of the pilot valve arrangement. The pressure medium source of substantially constant pressure is then the high pressure source, whereby in the second control chamber either the high pressure or a pressure dependent thereon is present. In the first control room maximum pressure is at. In order for the valve body of the valve to be controlled to be movable in a direction of action of the first control surface despite the constant application of the second control surface to the high pressure or the pressure derived therefrom, the first control surface is preferably larger than the second control surface.

In an alternative development of this variant, the second control chamber of the vorzusteuernden valve with the low pressure port of the pilot valve assembly or with a tank or with the atmosphere connected, in particular connected, and / or the valve body of vorzusteuernden valve is with a force, in particular the force of a spring , acted upon, in particular acted upon, which is directed opposite to a direction of action of the pressure acting on the first control surface pressure. The variant of the connection to the low-pressure connection or the tank is preferred when the valve to be controlled is a slide valve and thus a leakage flow from the first to the second control chamber is possible. The variant of the connection with the atmosphere is preferred when the second control chamber is sealed via a valve seat and thus "dry".

• Figur 1 ein erstes Ausführungsbeispiel einer Ventilanordnung mit vier 2/2-Pilotventilen in einer Brückenschaltung in einem schematischen seitlichen Schnitt;
• Figur 2 einen schematischen Schaltplan eines zweiten Ausführungsbeispiels mit vier 2/2-Pilotventilen in einer Brückenschaltung;
• Figur 3 einen schematischen Schaltplan eines zum zweiten Ausführungsbeispiel analogen dritten Ausführungsbeispiels mit einem 4/3-Pilot-Wegeventil;
• Figur 4 einen schematischen Schaltplan eines vierten Ausführungsbeispiels mit zwei 2/2-Pilotventilen;
• Figur 5 einen schematischen Schaltplan eines zum vierten Ausführungsbeispiel analogen fünften Ausführungsbeispiels mit einem 3/3-Pilot-Wegeventil;
• Figur 6 einen schematischen Schaltplan eines sechsten Ausführungsbeispiels mit zwei 2/2-Pilotventilen; und
• Figur 7 einen schematischen Schaltplan eines zum sechsten Ausführungsbeispiel analogen siebten Ausführungsbeispiels mit einem 3/3-Pilot-Wegeventil.

In the following, seven exemplary embodiments of a valve arrangement according to the invention will be explained in more detail with reference to seven schematic figures. Show it:

• FIG. 1 a first embodiment of a valve assembly with four 2/2-pilot valves in a bridge circuit in a schematic lateral section;
• FIG. 2 a schematic circuit diagram of a second embodiment with four 2/2-pilot valves in a bridge circuit;
• FIG. 3 a schematic circuit diagram of a third embodiment analogous to the second embodiment with a 4/3-way pilot valve;
• FIG. 4 a schematic circuit diagram of a fourth embodiment with two 2/2-pilot valves;
• FIG. 5 a schematic circuit diagram of an analogous to the fourth embodiment fifth embodiment with a 3/3-pilot-way valve;
• FIG. 6 a schematic circuit diagram of a sixth embodiment with two 2/2-pilot valves; and
• FIG. 7 a schematic circuit diagram of an analogous to the sixth embodiment seventh embodiment with a 3/3-way pilot valve.

For reasons of clarity, the same reference numerals are used for components or components that are designed to be consistent across the embodiments.

FIG. 1 shows a valve assembly 1 with a pilot valve assembly 2, which is flanged to a valve block 8 of the valve 6 for actuating a valve body 4, or a valve piston of a valve formed as a 4/3-way directional control valve 6. The pilot valve assembly 2 opposite to the valve block 8, an end plate 10 is flanged. The valve 6 has a high pressure chamber 12 which is connectable to a high pressure port, not shown. Furthermore, the valve 6 has low-pressure channels 14 and 16, which are connectable to a tank connection (not shown). At one in FIG. 1 upper side of the valve block 8, two consumer ports 18, 20 are arranged, via which the valve 6 is connectable to one or more consumers.

The valve body 4 is located according to FIG. 1 in a centered blocking position, so that the high-pressure chamber 12 is shut off against the consumer ports 18, 20 and the low-pressure channels 14, 16. In a region of a control surface 22 can be acted upon by control pressure and a second control surface 24 of the valve body 4, both the end plate 10 and a housing 26 of the pilot valve assembly 2, a first control chamber 28 and a second control chamber 30 on. For displacement of the valve body 4, or for pressure medium supply of one or more connectable to the consumer terminals 18, 20 consumers, the Control chambers 28, 30 acted upon by the pilot valve assembly 2 with a pressure medium volume flow. Since the two control surfaces 22, 24 are equal, there is a displacement of the valve body 4 at different pressures in the control chambers 28, 30. The displacement continues until no pressure difference between the control chambers 28, 30 is present.

For controlling the pressure medium volume flows directed into the control chambers 28, 30, the pilot valve arrangement 1 has a bridge circuit 32 with a first, second, third and fourth pilot valve 34, 36, 38 and 40. The pilot valves 34 to 40 are designed as 2/2-way valves. Each of the pilot valves 34 to 40 has a spring-biased basic position and an electromagnetically operable switching position. The bridge circuit 32 has a high pressure port 42, which is connected via a pressure medium channel 44 to a pressure medium source 46. In the pressure medium channel 44, a filter 48 is arranged. The bridge circuit 32 is designed analogously to a Wheatstone bridge. Accordingly, the first and third pilot valves 34 and 38 are connected in parallel with the high pressure port 42. Furthermore, the second and fourth pilot valves 36 and 40 are connected in parallel with a low-pressure port 50 of the bridge circuit 32, wherein the low-pressure port 50 is in turn connected to a pressure medium sink 52 or a tank. The low-pressure connection 50 is preceded by a throttle 54.

The bridge circuit 32 thus has between its high pressure port 42 and its low pressure port 50 two parallel pressure fluid flow paths 56, 58, wherein in a first pressure fluid flow path 56, the first pilot valve 34 is arranged in series with the second pilot valve 36. In the second pressure medium flow path 58 of the bridge circuit 32, the third pilot valve 38 is arranged in series with the fourth pilot valve 40 in analogy thereto. In this case, the first pilot valve 34 is connected via a connecting line to the second pilot valve 36 and the third pilot valve 38 via a different connecting line with the fourth pilot valve 40. In this case, a control line 60, 62 branches off from each of the two connection lines from a control connection 59, 61. In this case, a pressure medium output of the first pilot valve 34 is connected via the first control connection 59 and the first control line 60 to the first control chamber 28 and a pressure medium output of the third pilot valve 38 via the second control connection 61 and the second control line 62 to the second control chamber 30. The two Control lines 60, 62 form in this way a first diagonal or bridge, in which the valve body 4 of the valve 6 is hydraulically clamped.

The position of the valve body 4, and thus the pressure medium supply of the load ports 18 and 20, as already mentioned, controlled via the pilot valve assembly 2. This is connected to an operating unit 64, via which an operator can specify a desired value for a hydraulic consumer, which can be connected to one or both of the consumer connections 18, 20. For this purpose, the operating unit 64 is connected via a signal line 66 to a control unit 68 of the valve arrangement 1. Via further signal lines 70, 72 and 74, 76, the pilot valves 34, 36 and 38, 40 are connected to the control unit 68. Said signal lines 70 to 76 represent a signal connection between the control unit 68 and the respective electromagnets 78 to 84 of the pilot valves 34 to 40, or allow their energization. A signal connection between a displacement transducer 88 of the valve body 4 and the control unit 68 continues via a signal line 86. Via the position transducer 88, a position or deflection of the valve body 4 is permanently transmitted to the control unit 68 during normal operation.

Each of the pilot valves 34 to 40 is configured as a 2/2-way switching valve and has in each case a spring-biased basic position and an electromagnetically operable switching position. The first pilot valve 34 and the third pilot valve 38, which are arranged adjacent to the high-pressure connection 42 in the bridge circuit, have a spring-biased closed position as the basic position. The pilot valves 36 and 40, which are arranged adjacent to the low-pressure connection 50, have a spring-biased open position as their basic position.

If now the consumer port 20 are connected by the valve 6 to the high-pressure chamber 12, the valve body 4 in FIG. 1 be moved to the right so that a projecting into a control groove 90 Steuerfase 92 of the valve body 4 projects into the high-pressure chamber 12. It should be noted that the high-pressure chamber 12 from the observation level of FIG. 1 out to the viewer, partially extending around a control collar 94 of the valve body 4 around. In this way, a pressure medium connection from the high-pressure chamber 12 via a control gap, which is bounded by the Steuerfase 92 and a wall of the valve block 8, towards Consumer connection 20 manufactured. The farther the valve body 4 is moved to the right, the greater the control gap, can flow over the pressure medium from the high-pressure chamber 12 to the load port 20.

In FIG. 1 It can be clearly seen that when the valve body 4 is to be displaced to the right as described above, the second control chamber 30 must be pressurized from the high pressure port 42 via the third pilot valve 38 and the second control line 62, so that in the second control chamber 30th From the subsequent displacement of the valve body 4 and the incompressibility of the pressure medium resulting from the first control chamber 28, a pressure medium volume flow through the control line 60 and the second pilot valve 36 to the low pressure port 50 are enabled got to. The control unit 68 in this example thus has the task of keeping the first pilot valve 34 in its closed basic position, to control the third pilot valve 38 in the direction of its switching position or open position, to leave the second pilot valve 36 in its open position or to ballistically restrict it in the direction of its closed position and to drive the fourth pilot valve 40 in its closed position. Then, a pressure medium volume flow from the high pressure port 42 to the second control chamber 30 and an approximately equal pressure medium volume flow from the first control chamber 28 to the low pressure port 50 to flow.

According to the strength of the setpoint signal transmitted from the operating unit 64 to the control unit 68, there is the need for a more or less rapid deflection of the valve body 4 to the right. This results in the required size of the pressure medium volume flow to the second control chamber 30 and the pressure medium volume flow from the first control chamber 28. All four pilot valves 34 to 40 are pulse-width modulated electromagnetically actuated. This type of operation is in FIG. 1 symbolized over four schematically illustrated pulse trains. Under ballistic is to be understood that an actuating pulse is not sufficient to turn on the corresponding pilot valve to its switching position, if an intermediate position of the corresponding pilot valve is desired. For the third pilot valve 38, via which the second control chamber 30 is to be filled with pressure medium, it is assumed that the intended adjustment of the valve body 4 in FIG. 1 should be very slow to the right. Accordingly, the pressure medium volume flow in the second control chamber 30 must be small and finely dosed. To the solenoid of the pilot valve 38 is applied via the signal line 74 and the control unit 68 with pulses having a pulse duration t _i , which is only slightly greater than a minimum pulse duration t _{i, min} , which is necessary, the valve body of the third pilot valve 38 from to take off his basic position. Periodically recurring the valve body of the pilot valve 38 is thrown in this way in an intermediate position with a minimum opening cross-section and falls in the following pulse break back into the spring-biased home position or closed position. It should be noted that at the same time the fourth pilot valve 40 is controlled via the control unit 68 and the signal line 76 such that it is permanently shut off in its switching position or closed position. For this purpose, the pulse duration t _{i can have} a value which exceeds the switching time t _{s of} the fourth pilot valve 40. The fourth pilot valve 40 is therefore permanently closed. At the same time, the second pilot valve 36 remains open in its spring-biased home position or open position. Meanwhile, it is ensured that the first pilot valve 34 is also shut off in its spring-biased home position or closed position. In this way, a pressure medium volume flow generated by the displacement of the valve body 4 into the first control chamber 28 can flow out via the control line 60 and the second pilot valve 36 to the low-pressure connection 50 and into the tank 52.

During this control process, the measured value of the displacement transducer 88 or the position of the valve body 4 is permanently fed back to the control unit 68 via the signal line 86. If the pressure medium volume flow at the consumer connection 20 now corresponds to the desired value preset via the operating unit 64, then the control unit 68 causes an end of the movement of the valve body 4 in the valve block 8. For this purpose, the quantities of pressure medium that are present in the control lines 60 and 62 and in the control chambers 28 and 30 are held constant. Assuming that no leakage occurs in the system under consideration, this is achieved by the first and the third pilot valve 34 and 38 are energized, whereby they fall into their spring-biased closed positions or basic positions. Furthermore, the second and fourth pilot valves 36 and 40 are connected through the control unit 68 and the signal lines 72 and 76 in their closing or switching position.

If correspondingly larger pressure medium volume flows are to be conveyed from the high-pressure connection 42 to the control chambers 28 or 30, an opening cross-section of the pilot valves 34 (first) or 38 (third) is to be increased depending on the intended direction of movement of the valve body 4. This is achieved particularly fine-scale on the ballistic pulse width modulated electromagnetic actuation. The pulse duration it is t _i of the operating pulse compared with the case described above to enlarge for the intended larger volume flows.

With regard to the case discussed, it should be noted that a pressure medium volume flow actually conveyed into the second control chamber 30 can be reduced by the open position of the fourth pilot valve 40. A degree of reduction can be set as described above ballistic pulse width modulated. For this purpose, the control unit 68 acts on the electromagnet 84 of the fourth pilot valve 40 with pulses of corresponding pulse duration. Each pulse throws the valve body against the spring force in the direction of the switching position or closed position. In this case, the fourth pilot valve 40 fulfills an even more throttling function, the longer the pulse duration t _i . The fourth pilot valve 40 is then completely closed when the pulse duration t _{i is} sufficiently large and the pulse pause t _{p is} sufficiently small, so that the valve body remains in its switching position. In this case, the same applies of course in the case of filling the first control chamber 28 via the first pilot valve 34 and the control line 60. In this case, the second pilot valve 36 assumes the above-described Function of the fourth pilot valve 40.

Furthermore, it should be noted that a pressure medium volume flow conveyed into the control chambers 28 and 30 can not only be influenced as described above, but also via throttling of the pressure center volume flow flowing out of the respective other control chamber 30 or 28. The more strongly this is throttled, the slower the filling of the control chamber to be filled with pressure medium, resulting in a slower displacement of the valve body 4.

FIG. 2 shows a valve assembly 101 with a pilot valve assembly 102, via which the valve 6 is piloted. This corresponds to the vorzusteuernden valve 6 of the first embodiment according to FIG. 1 , In addition, the pilot valve arrangement 102 corresponds but largely with respect to a second and a fourth pilot valve 136, 140 of this. Unlike the second and fourth pilot valves 36, 40 in FIG FIG. 1 is the pilot valve 136, 140 spring-biased in its closed position. Otherwise, the second embodiment corresponds to FIG. 2 according to the first embodiment FIG. 1 ,

FIG. 3 shows a technically analogous solution to the second embodiment according to FIG. 2 , A valve arrangement 201 in this case has a pilot valve arrangement 202 for pilot control of the valve 6. Unlike the previous embodiments, the pilot valve assembly 202 now instead of a plurality of pilot valves only a first pilot valve 234, which is designed as a 4/3-way valve. The first pilot valve 234 has a high-pressure connection 142 connected to the pressure medium source 46, a low-pressure connection 250 connected to a tank, a first control connection 259 connected to the first control chamber 28 of the valve 6 via the first control line 60 and one to the second control chamber 30 of the valve 6 Connected via the second control line 62 second control terminal 261. Analogous to the two previous embodiments, the actuation of the first pilot valve 234 is carried out electromagnetically pulse width modulated and ballistic over the signal lines indicated by dashed lines.

FIG. 4 shows a device-simplified valve assembly 301 with a pilot valve assembly 302, unlike the second embodiment according to FIG. 2 between the high-pressure port 42 and the low-pressure port 50 has only one pressure medium flow path with the first pilot valve 34 and the second pilot valve 136. The two pilot valves 34, 136 correspond to the same named pilot valves of the embodiment according to FIG. 2 , Notwithstanding all previous embodiments, in this case the high-pressure port 42 is connected directly via the second control line 62 to a second control chamber 330 of the valve 306. In the second control chamber 330 is thus always on the high pressure. This is preferably substantially constant, but may also be variable. A displacement of a valve body 304 of the valve 306 in FIG. 4 from left to right thus takes place against acting in the second control chamber 330 high pressure of the high pressure port 42. Since at a full open position of the first pilot valve 34 in the first control chamber 28 of the valve 306 maximum this high pressure can be present, a second control surface 324, via the second control chamber 330 is limited, compared to the first control surface 22, via which the first control chamber 28 is limited, reduced in size. Thus, an imbalance of forces can occur for the displacement of the valve body 304. A displacement of the valve body 304 in FIG. 4 from right to left via the electromagnetic pulse width modulated and ballistic actuation of the second pilot valve 136, whereby pressure medium from the first control chamber 28 can flow to the low pressure port 50. The first pilot valve 36 remains in its spring-biased closed position.

A fourth embodiment according to FIG. 4 Technically analogous solution shows the fifth embodiment of a valve assembly 401 according to FIG. 5 , It differs from the valve assembly 301 according to FIG. 4 only in the embodiment of its pilot valve assembly 402. This has only a first pilot valve 434, which is designed as a 3/3-way valve. The first pilot valve 434 has a high-pressure port 242 connected to the pressure medium source 46, a low-pressure port 250 connected to the tank, and the first control port 259 connected to the first control chamber 28 via the first control line 60. The valve 306 corresponds to that of the fourth embodiment FIG. 4 , The first pilot valve 434 corresponds to the first pilot valve 434 of the still following seventh embodiment according to FIG. 7 and is also in both switch positions a, b electromagnetically pulse width modulated and ballistically actuated.

FIG. 6 shows a sixth embodiment of a valve assembly 501 with the pilot valve assembly 302, as already described in the fourth embodiment FIG. 4 and a valve 506 to be controlled. The valve arrangement 501 differs from the valve arrangement 301 according to FIG FIG. 4 only in the area of a second control surface 524 of a second control chamber 530 and its pressure medium supply. The second control chamber 530 is, unlike in all previous embodiments, connected to neither a second control port nor with a high pressure port of the pilot valve assembly. Instead, it is connected via a tank line 596 to a tank T, which has a low pressure level. Since this pressure level is insufficient to establish a balance of forces on the valve body 4, when the first control chamber 28 is acted upon by pressure medium via the high-pressure port 42, the valve body 4 is supported on a valve spring 598 via its second control surface 524. In a displacement of the valve body 4 in FIG. 6 to right, in which the first control chamber 28 is filled by the corresponding ballistic actuation of the first pilot valve 34 with pressure medium, the valve spring 598 is compressed accordingly. With a larger displacement of the valve body 4 thus increases their spring force, which counteracts a resulting from the high pressure applied to the first control surface 22 compressive force. If the valve body 4 in FIG. 6 are pushed to the left, the first pilot valve 34 is no longer (ballistic) driven and falls back into its spring-biased closed position. In addition, while the second pilot valve 136 is controlled ballistically in the direction of its switching position or opening position, so that pressure medium from the first control chamber 28 via the first control line 60 and the second pilot valve 136 to the tank T can flow out.

The seventh and last embodiment according to FIG. 7 shows a valve assembly 601 extending from the valve assembly 501 according to FIG. 6 only differs by a valve assembly 602. In principle, the valve assembly 302 is according to FIG. 6 by a first pilot valve 434, as already described in the fifth embodiment FIG. 5 shown is replaced. The control and operation of the valve 506 corresponds to that of the embodiment according to FIG. 6 , The structure and operation of the first pilot valve 434 in FIG. 7 correspond to the pilot valve 434 according to FIG. 5 ,

All dashed lines in the figures indicated signal lines without reference numeral connect the respective electromagnet of the pilot valve with a control unit according to FIG. 1 , The control unit is not shown for reasons of clarity.

The pilot valves shown are not limited to the ballistic or inverse ballistic operation, but may also be designed such that a conventional, in particular pulse width modulated, actuation is possible.

Each of the pilot valves can have the closed position or the open position as the basic position. Likewise, each of the pilot valves can be controlled ballistically or inversely ballistic. The choice of the basic position and / or the type of ballistic actuation depends on the particular application of the valve assembly or pilot valve assembly.

In a departure from the exemplary embodiment shown, the pilot valve arrangement can have more than four pilot valves, for example six or eight. Likewise, for a valve arrangement, two or more of the pilot valve arrangements can be interconnected, in particular connected in parallel with one another.

Disclosed is a hydraulic valve arrangement with a pilot valve arrangement and with a valve which can be precontrolled via the pilot valve arrangement. The hydraulic pilot valve arrangement for precontrol of the valve has at least one electromagnetic pulse width modulated actuated pilot valve. The pilot valve is ballistically or inversely ballistically actuated.

LIST OF REFERENCE NUMBERS

1; 101; 201; 301; 401; 501; 601;

valve assembly

2; 102; 202; 302; 402; 602

Pilot valve assembly

4; 304

valve body

6; 306; 506

Valve

8th

manifold

10

end disk

12

High-pressure chamber

14.16

Low pressure passage

18, 20

consumer connection

22

First control surface

24; 324; 524

Second control surface

26

casing

28

First control chamber

30; 330; 530

Second control chamber

32

bridge circuit

34; 234; 434

First pilot valve

36; 136

Second pilot valve

38

Third pilot valve

40; 140

Fourth pilot valve

42; 242

High pressure port

44

Pressure fluid channel

46

Pressure medium source

48

filter

50; 250

Low pressure port

52

Pressure medium sink

54

throttle

56

First pressure medium flow path

58

Second pressure medium flow path

59; 259

First control connection

60

First control line

61; 261

Second control connection

62

Second control line

64

operating unit

66

signal line

68

control unit

70, 72, 74, 76

signal line

78, 80, 82, 84

electromagnet

86

signal line

88

transducer

90

control groove

92

Steuerfase

94

control collar

596

tank line

598

valve spring

Claims (13)

1. Hydraulic valve arrangement having at least one hydraulic pilot valve arrangement (2; 102; 202; 302; 402; 602) for the pilot control of a valve, and having at least one valve (6; 306; 506) which is to be pilot controlled via the pilot valve arrangement (2; 102; 202; 302; 402; 602), the pilot valve arrangement (2; 102; 202; 302; 402; 602) having a first pilot valve (34; 234; 434) which can be actuated electromagnetically in a pulse width modulated manner, a high pressure connector (42; 242) for connection to a pressure medium source (46), and a low pressure connector (50; 250) for connection to a pressure medium sink (52), and the pilot valve arrangement (2; 102; 202; 302; 402; 602) having a first control connector (59; 259) which is connected or at least can be connected to a first control space (28) of the valve (6; 306; 506) to be pilot controlled, it being possible for the first control connector (59; 259) to be connected to the high pressure connector (42; 242) or to the low pressure connector (250) via an open position of the first pilot valve (34; 234; 434), characterized in that the pilot valve arrangement has a control unit (68) which is configured in such a way that, via it, at least the first pilot valve (34; 234; 434) can be ballistically actuated electromagnetically in a pulse width modulated manner.
2. Valve arrangement according to Patent Claim 1, the pilot valve arrangement (2; 102; 302) having a second pilot valve (36; 136) which is connected in series with the first pilot valve (34) in a pressure medium flow path (56) from the high pressure connector (42) to the low pressure connector (50), and the first (34) or the second pilot valve (36; 136) being arranged in a pressure medium flow path from the high pressure connector (42) to the first control connector (59), and the respective other of the said two pilot valves (36; 136, 34) being arranged in a pressure medium flow path from the first control connector (59) to the low pressure connector (50).
3. Valve arrangement according to either of Patent Claims 1 and 2, the pilot valve arrangement (2; 102; 202) having a second control connector (61; 261) for connection to a second control space (30) of the valve (6) to be pilot controlled.
4. Valve arrangement according to Patent Claim 3, the pilot valve arrangement (2; 102) having a third (38) and a fourth pilot valve (40), the third pilot valve (38) being connected in series with the fourth pilot valve (40) in a pressure medium flow path (58) from the high pressure connector (42) to the low pressure connector (50), and the third (38) or the fourth pilot valve (40) being arranged in a pressure medium flow path from the high pressure connector (42) to the second control connector (61), and the respective other of the said two pilot valves (40, 38) being arranged in a pressure medium flow path from the second control connector (61) to the low pressure connector (50).
5. Valve arrangement according to one of Patent Claims 1 to 4, at least the first pilot valve (34) being configured as a 2/2-way switching valve.
6. Valve arrangement according to Patent Claim 1, the first pilot valve (234; 434) being a directional valve which has the high pressure connector (242), the low pressure connector (250) and the first control connector (259) .
7. Valve arrangement at least according to Patent Claims 1, 3 and 6, the directional valve having the second control connector (261).
8. Valve arrangement according to one of the preceding patent claims, at least the first pilot valve (34; 234; 434) being configured as a seat valve or as a slide valve.
9. Valve arrangement according to one of the preceding patent claims, the second (36; 136) and/or the third (38) and/or the fourth pilot valve (40; 140) being ballistically actuable electromagnetically in a pulse width modulated manner.
10. Valve arrangement according to Patent Claim 3 or according to one of the patent claims which refer back to Patent Claim 3, it being possible for the second control connector (61; 261) of the pilot valve arrangement (2; 102; 202) to be connected to a second control space (30) of the valve (6) to be pilot controlled.
11. Valve arrangement according to one of the preceding patent claims, the first control space (28) of the valve (306; 506) to be pilot controlled being delimited at least in sections via a first control face (22) of a valve body (304; 4) of the valve (306; 506) to be pilot controlled, and a second control space (330; 530) of the valve (306; 506) to be pilot controlled being delimited at least in sections via a second control face (324; 524) of the valve body (306; 506), which second control face (324; 524) acts counter to the first control face, and it being possible for the second control space (330; 530) to be connected to a connector with a substantially constant pressure.
12. Valve arrangement according to Patent Claim 11, it being possible for the second control space (330) of the valve (306) to be pilot controlled to be connected to the high pressure connector (42; 242) of the pilot valve arrangement (302; 402), and the first control face (22) being greater than the second control face (324).
13. Valve arrangement according to Patent Claim 11, it being possible for the second control space (530) of the valve (506) to be pilot controlled to be connected to the low pressure connector of the pilot valve arrangement (302; 602) or to a tank (T) or to atmosphere, and/or it being possible for the valve body (4) of the valve (506) to be pilot controlled to be loaded with a force which is directed counter to a direction of action of the pressure which acts on the first control face (22).

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