Valve

Abstract

The invention relates to a valve comprising a valve housing (10) which has two fluid connection points (12, 14) for guiding a fluid and comprising an actuation device (16) for actuating a main piston (18) of a seat valve (20), said main piston being received in the valve housing (10). The valve housing (10) together with the seat valve (20) receives a nonreturn valve (22). The invention is characterized in that at least one bypass line (24) runs in the valve housing (10), said bypass line allowing a flow of fluid present at the fluid connection point (12) in the direction of a valve chamber (26) in the open state of the seat valve while bypassing the nonreturn valve (22), said flow being controllable by the main piston (18) of the seat valve (20).

Description

[0001] valve

[0002] The invention relates to a valve with a valve housing having two fluid connection points for conducting fluid and with an actuating device for actuating a main piston of a seat valve accommodated in the valve housing, wherein a check valve is accommodated in the valve housing together with the seat valve.

[0003] From DE 10 2012 015 354 A1 a valve is known, in particular a pilot-operated proportional directional control valve, with a valve housing which has a fluid inlet and a fluid outlet, wherein the fluid flow between the fluid inlet and the fluid outlet can be regulated by a main piston, wherein a pilot valve chamber is provided on a rear side of the main piston with a pilot valve closing element which can be moved by an actuating device and with which the fluid flow between the pilot valve chamber and the fluid outlet can be regulated, wherein an inlet orifice is arranged between the fluid inlet and the pilot valve chamber, the opening cross-section of which can be reduced by a control element.

[0004] Furthermore, a maximum volume flow regulator is provided within the valve housing. It has a control piston similar to a spring-loaded check valve, which is acted upon on one side by the pressure of the fluid flowing from the pilot chamber and on the other side by a compression spring. A flow regulator is thus integrated within the valve, and the inlet orifice cross-section, which can be reduced by means of the control element, causes the pressure in the pilot valve chamber to drop, thus opening up the possibility of actively controlling the opening stroke of the main piston in addition to the regulation at the pilot valve seat. The smaller the differential pressure between the fluid inlet and fluid outlet, the larger the opening stroke of the valve can be adjusted, enabling the flow control function.

[0005] Based on this prior art, the invention seeks to create a valve that, comparable to the known solution, combines two different valve types in a common housing in a space-saving manner, with the aim of increasing the application possibilities for such valve designs. This object is achieved by a valve device having the features of patent claim 1.

[0006] Because, according to the characterizing part of patent claim 1, at least one bypass line runs in the valve housing, which bypasses the check valve and forwards a fluid flow present at one fluid connection point, which can be controlled by the main piston of the seat valve, in the open state of the latter in the direction of a valve chamber, the check valve integrated in the valve housing is, if required, able to discharge fluid on the consumer side via the valve into the subsequent fluid circuit at a very low opening pressure and with little flow loss, again with a relatively large opening cross section.

[0007] This makes it possible to expand the application range for such valve designs. For example, the valve can be combined very well with hydraulic damping cylinders as the consumer, particularly in the form of so-called stabilizers as part of a vehicle's chassis. Using the valve according to the invention, the respective stabilizer can be designed to be stiffer for cornering than for off-road driving, where a softer suspension deflection is generally desired.

[0008] In a preferred embodiment of the valve according to the invention, the seat valve is a 2 / 2-way seat valve, in particular a pilot-operated 2 / 2-way seat valve. In this way, the volume flow can be released in the opposite direction to the check valve via an electrical signal to the actuating device depending on the switching position of the seat-tight 2 / 2-way valve. In a further embodiment as a modular system, the 2 / 2-way seat valve can be normally open (NO) or normally closed (NC) in its basic position, depending on the selected design. The internal return of the fluid from one connection point in the valve housing to the rear of the 2 / 2-way seat valve makes it possible to design the valve with only two connections. The check valve is preferably arranged in a fluid connection between one and the other fluid connection point in the valve housing.

[0009] The check valve preferably has a spring-loaded closing body that blocks the fluid connection in the direction of the other fluid connection point as soon as the fluid pressure at one fluid connection point is greater than at the other fluid connection point. However, if the fluid pressure at the other fluid connection point is greater than at the first fluid connection point, the check valve opens.

[0010] The modular system for the valve enables solutions in which, in an actuated position of the 2 / 2-way seat valve, a fluid flow from the bypass line into the valve chamber is blocked or released, and in a deactuated position, it is released or blocked. Particularly favorable flow forces when introducing fluid into the valve arise when the closing body of the check valve and the piston-like main piston of the 2 / 2-way seat valve are guided longitudinally in the valve housing, adjacent to the additional fluid connection point and opposite each other in the direction of action, with the valve chamber permanently connected to the additional fluid connection point by means of a fluid flow. In particular, the closing and main pistons are arranged concentrically to the longitudinal or travel axis of the valve.

[0011] Preferably, a permanent orifice plate is provided between the valve chamber and the additional fluid connection point. This optional integration of an orifice plate allows for control of the flow rate via the 2 / 2-way seat valve.

[0012] In a preferred embodiment of the valve according to the invention, it is further provided that the pilot control of the seat valve comprises a pilot piston that passes through the main piston of the seat valve and is operatively connected to the main piston by means of an energy accumulator, such as a compression spring. For indirect control of the main piston, the actuating device acts exclusively on the pilot piston.

[0013] The pilot piston preferably controls an axial orifice in the main piston, which, in the released state, establishes a permanent fluid connection between the valve chamber and a pilot chamber that is at least partially delimited by the valve piston. In addition, the main piston has a radial orifice that can be supplied with fluid via a fluid guide between the outer circumference of the main piston and the adjacent inner circumference of the valve housing and that opens into the pilot chamber. When the pilot piston is open, i.e. the pilot piston has lifted off from the pilot seat of the main piston, pilot oil flows via the series-connected radial orifice and the pilot seat or axial orifice, whereby the resulting pressure difference at the radial orifice ensures a lower pressure in the pilot chamber, which ultimately opens the seat valve by means of the main piston.The free diameter of the radial orifice is selected slightly smaller than the free diameter of the axial orifice. Otherwise, such valve pilot controls are state of the art, as shown, for example, in DE 10 2012 015 354 A1.

[0014] Preferably, the actuating device used has a magnetic coil, when energized, a magnetic armature actuates the pilot piston, so that the main piston, which is indirectly controlled in this respect, moves into a position blocking the fluid flow between the respective bypass line and the valve chamber or into a position releasing it.

[0015] In the following, the valve solution according to the invention is explained in more detail using two exemplary embodiments according to the drawing. In a schematic representation and not to scale,

[0016] Figure 1 in the form of a longitudinal section a currentless open

[0017] Valve in non-actuated position;

[0018] Figure 2 shows the same valve as in Figure 1 in activated and therefore closed position;

[0019] Figure 3 shows the hydraulic circuit diagram of the normally open

[0020] Valve according to Figure 1;

[0021] Figure 4 shows, in the form of a longitudinal section, another normally closed valve in the non-actuated position;

[0022] Figure 5 shows the same valve as in Figure 4 in the activated and thus open position; and Figure 6 shows the hydraulic circuit diagram of the normally closed valve according to Figure 4.

[0023] The valve shown in Figure 1 comprises a valve housing designated 10 as a whole. The valve housing 10 can be constructed in several parts as shown in Figure 1 and can be accommodated in a valve block (not shown in detail) in the usual way using appropriate sealing systems. The valve housing 10 has two fluid connection points 12, 14 for conducting fluid, for example in the form of a hydraulic medium. Furthermore, the valve has an actuating device designated 16 as a whole for actuating a main piston 18 of a seat valve designated 20 as a whole, which is accommodated in the valve housing 10. Together with the seat valve 20, a check valve 22 is accommodated in the aforementioned valve housing W.A characteristic of the invention is that, starting from the free end face of the valve housing 10, a bypass line 24 at least partially passes through the latter. This bypass line, bypassing the check valve 22, directs a fluid flow present at one fluid connection point 12 toward a valve chamber 26 when the seat valve 20 is open. This fluid flow is thus controlled by the main piston 18 of the seat valve 20. The main or valve piston 18 and the pilot piston 44 form a 2 / 2-way seat valve, in particular a pilot-operated 2 / 2-way seat valve, which will be explained in more detail below.

[0024] The check valve 22 is arranged in a fluid connection between one fluid connection point 12 and the other fluid connection point 14. The check valve 22 has a spring-loaded closing body 28, which blocks the fluid connection in the direction of the other fluid connection point 14 as soon as the fluid pressure at one fluid connection point 12 is greater than at the other fluid connection point 14. In Figure 1, the closing body 28 is in its position blocking the aforementioned fluid connection; this is supported by a closing spring 29, which acts on the closing body 28 and is designed as a compression spring. The check valve 22 has a so-called tripod 30 on the inlet side facing the fluid connection point 12, which makes it possible to establish the aforementioned fluid connection by fluid flow between the legs of the tripod 30.When the check valve 22 is open, as shown in Figure 2, fluid that is present at the further fluid connection point 14 flows unhindered towards the fluid connection point 12 via the aforementioned fluid connection. When the check valve 22 is open, oil always flows from the connection point 14 to the connection point 12 because the check valve 22 forces itself open. When the check valve 22 is closed, the fluid path in this direction is blocked. The channel-like further fluid connection point 14 engages radially into the valve housing W, establishing a permanent fluid connection to a fluid chamber 32 in the valve housing 10. The channel-like fluid connection point 14 can establish the fluid connection to the central fluid chamber 32 several times along the outer circumference of the valve housing 10.

[0025] The main piston 18 is designed as a valve piston of the seat valve 20 and is shown in its open position in Figure 1. The free end of the main piston 18 lifts off a conical valve seat 34 in the valve housing 10. When the seat valve 20 is open, as shown in Figure 1, a fluid connection is established via the valve seat 34 between a pre-valve chamber 36 and the actual valve chamber 26. The pre-valve chamber 36 is selected to be larger in diameter than the valve chamber 26, and the valve seat 34 with its wall ensures the transition between the two chambers 26 and 36.Furthermore, the pre-valve chamber 36 is permanently connected to the bypass line 24, which extends parallel to a longitudinal axis 38 of the valve. Although not shown in detail, if necessary, several such bypass lines can be accommodated in the valve housing 10, arranged parallel to the longitudinal axis 38 and radially spaced from one another. Furthermore, an orifice 40 with a predeterminable cross-section is provided between the valve chamber 26 and the fluid chamber 32.

[0026] The difference in diameter between the piston diameter of the main piston 18 and the valve seat 34 forms a kind of circular ring, and the area of ​​this circular ring is selected to be approximately half the size of the oppositely arranged rear side of the piston, which has the largest diameter. If the pressure on the rear side of the main piston 18 is virtually half the pressure on the aforementioned circular ring, then the piston can move to the right as viewed in Figure 1. This diameter design for a main piston 18 in a pilot-operated seat valve 20 is common practice, so it will not be discussed in more detail here. The pilot control for the main piston 18, i.e. for the seat valve 20, is designated as a whole by 42. The aforementioned pilot control 42 has a pilot piston 44, which extends through the main piston 18 while partially maintaining a radial distance to the main piston 18.According to the illustration in Figure 1, a piston tip of the pilot control piston 44 engages in an axial orifice 46 in the main piston 18 and when the axial orifice 46 is released via the pilot control piston 44, a fluid-carrying connection is created between a pilot control chamber 48 and the chamber 26.

[0027] Furthermore, the piston-shaped main piston 18 has a radial orifice 50 on an outer peripheral side, which is permanently fluid-conductingly connected to the pre-valve chamber 36 via a channel-like fluid guide 52 and is thus in permanent fluid communication with the bypass line 24, which is connected to the fluid connection point 12. In particular, the channel-like fluid guide 52 is created via a recessed groove along the outer circumference of the main piston 18. The rear side of the main piston 18 is not supported on a plate guide 54, through which the pilot control piston 44 passes, but rather serves as a bearing for a conical compression spring 56, the other free end of which is applied to a further plate guide 58, which is firmly connected to the pilot control piston 44.The piston stroke of the main or valve piston 18 is limited by the fact that when the main piston 18 reaches the pilot piston 44, the pilot oil flow stops and the main piston 18 can then no longer open.

[0028] The pilot control piston 44 can be controlled by an actuating rod 60, in particular in the housing of the actuating device 16, that is to say within the magnet assembly, the actuating rod 60 resting with its one end against the pilot control piston 44 and with its other end or end region engaging in the usual way in a magnet armature 62, which is guided longitudinally displaceably in a pole tube 64 and, when a coil winding 66 of the actuating device 16 is energized, moves from its de-energized initial position according to Figure 1 into its energized actuating position according to Figure 2, the main piston 18 being controlled in this way indirectly via the pilot control piston 44, in particular being moved into its closed position according to Figure 2, in which the fluid connection between the pre-valve chamber 36 and the valve chamber 26 is interrupted, in which the conical contact part of the main piston 18 comes into contact with the valve seat 34 in the valve housing 10.The pilot control piston 44 closes the valve seat 46. This stops the pilot oil flow and no more pilot oil flows at the radial orifice 50. The pressure difference across this orifice therefore becomes zero and the pressure on the back of the main piston 18 is the same as on the annulus 36. Due to the fact that the back of the main piston 18 has twice the area of ​​the annulus 36, a force is generated which closes the main piston 18. The aforementioned pilot control with axial orifice 46 and radial orifice 50 is also common (DE 10 2012 015 354 A1), so it will not be discussed in detail here. The actuating device 16 therefore acts on the pilot control piston 44 as shown and closes or opens the pilot control seat in the form of the axial orifice 46 in the energized or de-energized state.When the pilot control piston 44 is open, pilot oil also flows via the series-connected radial orifice 50 and the pilot seat in the form of the axial orifice 46 in the direction of the valve chamber 26 with a further orifice 40, whereby the pressure difference at the radial orifice 50 ensures a lower pressure in the pilot control chamber 48, which ultimately leads to the opening of the main piston 18 as shown in Figure 1. Thanks to the pilot control stage, i.e. due to the pilot control 42, the seat valve 20 can be actuated by means of the actuating device 16 with low magnetic forces and thus in an energy-saving manner. It is understood that in order to energize the coil winding 66, the actuating device 16 can be connected to a power supply source in the usual way via a plug 68.In order to avoid any obstacles in the operation of the magnet armature 62, both the actuating rod 60 and the magnet armature 62 are provided with a through-bore so that the pressure prevailing in the pilot chamber 48 also takes effect on the back of the magnet armature 62 and thus enables pressure-balanced valve operation.

[0029] As can be further seen from the circuit diagram in Figure 3, a hydraulic consumer (not shown in detail) is connected between the two fluid connection points 12, 14 on the output side of the valve. This consumer may be a hydraulic working cylinder, such as a damping or stabilizing cylinder. Also connected between the fluid connection points 12, 14 on the valve side is the check valve 22, which blocks in the direction toward the connection point 14 and opens in the opposite direction.Furthermore, at least one single bypass line 24 is connected to the fluid connection point 12 and bypassing the check valve 22, which in turn is connected on the output side to the electromagnetically actuated seat valve 22 on the input side, which, as shown in Figure 3, is held in the open position according to Figure 1 by means of the pilot control 42, wherein the actuating device 16 is not energized and the open position (NO) is reached using the compression spring 56.

[0030] However, since, as shown in Figure 2, the main piston 18 of the seat valve 20 is held closed by the actuating device 16 with a magnetic force in the order of magnitude of approximately 8 to 10 bar of fluid pressure, the internal check valve function will only come into effect if, as part of a pressure relief function, the fluid pressure present in the valve chamber 26 is higher than the magnetic force of the actuating device 16 holding the main piston 18. Normally, if the fluid pressure at the further fluid connection point 14 is greater than at the first fluid connection point 12, the check valve 22 opens in the direction of the fluid connection point 12 and thus releases the fluid connection from 14 to 12 via the fluid chamber 32 in the valve housing 10.The check valve 22 used for this purpose has only a very small opening pressure of, for example, 0.2 to 0.5 bar; however, as shown in particular in Figure 2, it releases a very large flow cross-section between the closing body 28 of the check valve 22 and the associated adjacent valve seat 72 in the valve housing 10, so that with an extremely small pressure difference, a discharge takes place via the fluid connection point 12 from one actuator side of the hydraulic consumer to the other actuator side, to which the valve is connected according to the figures.

[0031] Even when the seat valve 20 is actuated, the valve design specifies that preferably 95% of the fluid flows from the connection point 14 to the connection point 12, whereas only approximately 5% of the fluid is to be returned from the fluid connection point 14 via the seat valve 20 and the bypass line 24, bypassing the check valve 22, to the fluid connection point 12, which is acceptable. To keep the check function of the check valve 22 "moderate," i.e., to ensure a low opening pressure with low pressure losses AP, the associated closing spring 29, which actuates the closing body 28, is provided with only a low spring force and, in this respect, is responsible for a correspondingly "soft" actuation, ensuring the timely opening process with the closing body 28 at low fluid pressures.

[0032] While Figure 1 shows a valve solution in which the valve is open in the de-energized state (NO), Figure 2 shows the closed valve solution in the energized state. When the pilot piston 44 is open, the valve closes when flowing from valve chamber 26 to valve chamber 36, and only a limited volume flow is possible via the two orifices 46, 50. In the embodiment according to Figures 4 and 5, the valve assumes its closed position (NC) in the de-energized state or is open in the energized state, as shown in Figure 5. For this purpose, the compression spring 56 according to Figures 1 to 3 is omitted, and instead such a compression spring 74 is arranged between the movable magnet armature 62 and a pole core 63 of the pole tube 64. The aforementioned components are enclosed in a magnet housing 65.Furthermore, the pilot piston 44 is firmly connected to one of the free end faces of the solenoid armature 62 via a snap ring connection 76. Thus, when the actuating device 16 is de-energized, the compression spring 74 exerts a force on the solenoid armature 62, thus actuating the pilot control 42 such that the main piston 18 of the seat valve 20 moves into its closed position as shown in Figure 4.

[0033] However, if the actuating device 16 is energized as shown in Figure 5, the solenoid armature 62, when the compression spring 74 is compressed, moves into its right-hand actuating position as viewed in the direction of travel, in which position the pilot control 42 actuates the main piston 18 in such a way that a releasing fluid connection is established between the fluid connection points 12, 14 via the respective bypass line 24, the pre-valve chamber 36, the thus released valve seat 34, the valve chamber 26, the orifice 40, the fluid chamber 32 and the radial channel guide to the fluid connection point 14 from the direction of the connection point 12. Otherwise, the structure of the valve according to Figures 4 and 5 essentially corresponds to the structure of the valve according to Figures 1 and 2, and it is clear that a type of modular system has been created in which various types of such valves can be realized with a few basic components in a standardized design.In this respect, the same components are also represented with the same reference numerals for all components of the valves according to Figures 1 to 6, and the explanations given for the first embodiment also apply to the second embodiment.

[0034] Figure 6 shows a circuit diagram position corresponding to Figure 3, now for the valve solution according to Figures 4 and 5. Accordingly, in the de-energized state (NC), the seat valve 20 is closed (Figure 4) and in the energized state, it is open (Figure 5). Accordingly, for all valve solutions according to Figures 1 to 6, the central task is fulfilled: to guide the fluid volume flow in one flow direction, preferably from the fluid connection point 14 to the fluid connection point 12 via the check valve 22 with a very low opening pressure and low flow losses. Depending on the switching position of the seat-tight 2 / 2-way seat valve 20, the volume flow from connection 12 to connection 14 is blocked or released by means of an electrical signal at the actuating device 16. The volume flow can be influenced sensibly using the orifice plate 40.Depending on the design, the 2 / 2-way seat valve 20 can be normally open (NO), as shown in Figure 1, or normally closed (NC), as shown in Figure 4. By integrating two valves 20 and 22 in a common valve housing 10, additional valves and associated external piping can be dispensed with, which helps save costs and increases functional reliability.

Claims

Patent claims 1. Valve with a valve housing (10) which has two fluid connection points (12, 14) for conducting fluid and with an actuating device (16) for actuating a main piston (18) of a seat valve (20) which is accommodated in the valve housing (10), wherein a check valve (22) is accommodated in the valve housing (10) together with the seat valve (20), characterized in that at least one bypass line (24) runs in the valve housing (10), which bypasses the check valve (22) and forwards a fluid flow which is present at one fluid connection point (12) and can be controlled by the main piston (18) of the seat valve (20) in the direction of a valve chamber (26) when the latter is in the open state.

2. Valve according to claim 1, characterized in that the seat valve (20) is a 2 / 2-way seat valve, in particular a pilot-operated 2 / 2-way seat valve.

3. Valve according to claim 1 or 2, characterized in that the check valve (22) is arranged in a fluid connection between the one (12) and the other fluid connection point (14).

4. Valve according to one of the preceding claims, characterized in that the check valve (22) has a spring-loaded closing body (28) which blocks the fluid connection in the direction of the other fluid connection point (14) as soon as the fluid pressure at one fluid connection point (12) is greater than at the other fluid connection point (14).

5. Valve according to one of the preceding claims, characterized in that in an actuated position of the seat valve (20) a Fluid flow from the bypass line (24) into the valve chamber (26) is blocked (NC) or released (NO) and is released (NO) or blocked (NC) in an unactuated position. Valve according to one of the preceding claims, characterized in that the closing body (28) of the check valve (22) and the main piston (18) of the seat valve (20) are guided longitudinally displaceably in the valve housing (10) adjacent to and opposite the further fluid connection point (14), and that the valve chamber (26) is permanently connected to the further fluid connection point (14) in a fluid-conducting manner. Valve according to one of the preceding claims, characterized in that an orifice (40) is permanently connected between the valve chamber (26) and the further fluid connection point (14), which orifice can generate a volume flow-dependent differential pressure in a flow direction from the fluid connection point (12) to the further fluid connection point (14).Valve according to one of the preceding claims, characterized in that the pilot control (42) of the seat valve (20) has a pilot piston (44) that passes through the main piston (18) of the seat valve (20) and is operatively connected to the pilot piston (44), preferably by means of an energy accumulator, such as a compression spring (56, 74). Valve according to one of the preceding claims, characterized in that for indirect control of the main piston (18), the actuating device (16) acts exclusively on the pilot piston (44). Valve according to one of the preceding claims, characterized in that the pilot piston (44) controls an axial orifice (46) in the main piston (18), which in the released state establishes a permanent fluid connection between the pilot chamber (48) and the valve chamber (26). Valve according to one of the preceding claims, characterized in that the main piston (18) additionally has a radial orifice (50) which can be supplied with fluid via a fluid guide (52) between the outer circumference of the main piston (18) and the adjacent inner circumference of the valve housing (10) and which opens into the pilot chamber (48). Valve according to one of the preceding claims, characterized in that the actuating device (16) has a coil winding (66), upon energization of which a magnet armature (62) actuates the pilot piston (44), so that the main piston (18) moves into a Fluid guide between the respective bypass line (24) and the valve chamber (26) moves into a position blocking or releasing it.

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