A valve arrangement for controlling a hydraulic actuator

Abstract

The disclosure relates to a valve arrangement (1) for controlling a hydraulic actuator (M), the valve arrangement (1) comprising a main valve house (3), having an inlet port (P) fluidly connectable to a first main outlet (2), a second main outlet (4) and a tank outlet (T), wherein the first main outlet (2) and the second main outlet (4) are fluidly connectable to the actuator (M) allowing a direction of flow through the actuator (M) in a first flow direction in which the actuator (M) is controlled in a first actuator direction or in a second flow direction which the actuator (M) is controlled in a second actuator direction and a first valve body (10), a second valve body (20), the first valve body (10) comprises first passage (14), configured such that the first valve body (10) allows a fluid flow from the actuator (M) to the tank outlet (T), when in the first open position and. The second valve body (20) comprises a second passage (23), configured such that the second valve body (20) allows a fluid flow from the inlet port (P) to the actuator (M), when in the second closed position.

Description

[0001] A valve arrangement for controlling a hydraulic actuator

[0002] Technical field

[0003] The present disclosure relates to a valve arrangement for controlling a hydraulic actuator. More specifically, the disclosure relates to a valve arrangement for controlling a hydraulic actuator as defined in the introductory parts of the independent claim.

[0004] Background art

[0005] Hydraulic and pneumatic systems and components are used, inter alia, for the transfer of power or energy and to operate and control actuators such as motors, cylinders or booms in machines or mechanical devices. An important component of such systems is a valve arrangement, which is a combination of valves, inlets and outlets. A valve arrangement controls or adjusts the actuator, which is connected via the valve arrangement to a pump acting as pressure medium source either directly or via the valve arrangement to a fluid tank. There are many different ways to control the valves in the valve arrangement, for example, manually or electro-mechanically operated valves, and valves that react to fluid pressure or flow in the pipeline, e.g. pressure relief valves or the constant flow valves.

[0006] Controlling large flows requires a large force to operate the valve that regulates the flow. For instance, it requires a large and powerful electro-mechanical device for opening or closing an electro-mechanically controlled valve for high flow.

[0007] A known valve arrangement of this kind and for this purpose is a direct controlled proportional valve that can control a flow in two directions. This type of valve arrangement can handle high pressures in a tank port even if a hose for return oil is not connected.

[0008] One way to reduce the external force required to operate a valve is by utilizing the pressure or flow from the main source as a power source. A pilot valve can be used to regulate a much higher pressure or flow feed to the valve, which would otherwise demand a significantly larger force for operation. Pilot valves are typically positioned externally to the valve and connected to it through one or more fluid conduits with an outlet into the main flow area of the valve chamber. To control an actuator in different directions, the flow must be managed in two opposite directions. A problem with direct controlled proportional directional valves is that the spools are small and the adjustment force is low. This causes high pressure loss and loss of energy efficiency.

[0009] Another known valve arrangement is a pilot-operated proportional valve. This type of valve is a hydraulic valve used to control the flow of fluid in systems where precise and variable control is necessary. It consists of a main valve and a pilot valve, with the pilot valve receiving a control signal from an external source to adjust the opening of the main valve. To ensure the correct position, these valves often use a feedback system, typically a sensor monitoring the actual flow. An essential characteristic of this type of valve is its proportionality, enabling linear adjustment of the flow in relation to the control signal.

[0010] A problem with pilot controlled proportionally valves is that they cannot handle high pressure for the return oil. Another problem is that pilot controlled proportionally valves only use one long spool which makes this type of valve arrangement long, which limits the usefulness in small spaces.

[0011] A valve arrangement, known from SE439342 B, is arranged for controlling a linear or rotary hydraulic actuator in terms of both speed and direction of travel. This type of valve arrangement uses pilot valves to control a pilot flow wherein the pilot flow controls the main supply flow. This type of valve arrangement is complex in design and requires a lot of components to control the flow in two directions.

[0012] A valve arrangement, known from SE531388 C2, can regulate the flow in two directions with help of a pilot flow and check valves. It does not determine the direction of the fluid flow. This type of valve arrangement uses the fluid flow from the minus-side of an actuator to be used on the plus-side of the actuator.

[0013] Another problem with known valves is that multiple valves, each requiring a separate control arrangement, are needed to control an actuator, which makes the valves complex and large in size which limits the usefulness in small spaces. It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and in particular there is a need for a valve arrangement that has a simpler construction than the ones known in the prior art.

[0014] According to a first aspect there is provided a valve arrangement for controlling a hydraulic actuator, such as a motor, cylinder or booms, the valve arrangement comprising a main valve house having an inlet port fluidly connectable to a first main outlet, a second main outlet and a tank outlet. The first main outlet and the second main outlet are fluidly connectable to the actuator allowing a direction of flow through the actuator in a first flow direction in which the actuator is controlled in a first actuator direction. A first valve body is continuously movable in the main valve house between a first open position in which the inlet port is in fluid connection with the second main outlet allowing a flow in the first flow direction, and a first closed position in which the inlet port is blocked from allowing a flow from the inlet port to the second main outlet. A first valve body control arrangement of the valve arrangement is arranged to control the position of the first valve body. The first valve body comprises a first passage, configured such that the first valve body allows a fluid flow from the actuator through the first main outlet to the tank outlet, when in the first open position. The first valve body control arrangement can be an electrical or a hydraulic actuator arranged to control the position of the first valve body.

[0015] The valve arrangement is advantageous since the first valve body directly controls the fluid flow from the main inlet to the second main outlet through the actuator via the first main outlet and out through the tank outlet. Therefore, a high fluid flow can be achieved and thereby reducing the pressure drop across the valve arrangement. By separately arranging the first valve body control arrangement and the first valve body in the valve arrangement a smaller valve arrangement is achieved.

[0016] In some embodiments, the main valve house further allows a direction of flow through the actuator in a second flow direction in which the actuator is controlled in a second actuator direction. In such embodiments, the valve arrangement further comprises a second valve body, which is continuously movable in the main valve house between a second open position in which the inlet port is in fluid connection with the first main outlet allowing a flow in the second flow direction, and a second closed position in which the inlet port is blocked from allowing a flow from the inlet port to the first main outlet. A second valve body control arrangement of said valve arrangement is arranged to control the position of the second valve body. The second valve body comprises a second passage, configured such that the second valve body allows a fluid flow from the inlet port to the actuator, when the second valve body is in the second closed position and the first valve body is in the first open position. The second valve body comprises a third passage, configured such that the second valve body allows a fluid flow from the actuator through the second main outlet to the tank outlet when the second valve body is in the second open position. The second valve body control arrangement can be an electrical or a hydraulic actuator arranged to control the position of the second valve body.

[0017] By arranging the main valve house with a second valve body, the direction of flow can be directed in two different directions, namely in either the first flow direction or in the second flow direction. By arranging the second valve body with the second and third passage, an even more compact valve arrangement is achieved since the flow can be directed in two different directions using one valve arrangement with only two valve bodies. An advantage of arranging the main valve house with both the first valve body and the second valve body is that valve arrangement can be used in small spaces.

[0018] In an example, the first valve body control arrangement and the second valve body control arrangement are arranged to control the first and the second valve body in such a way that only one of the first valve body and second valve body can be in their respective open position at a time. In other words, when the first valve body control arrangement controls the first valve body to the first open position, the second valve body control arrangement controls the second valve body to the second closed position. When the second valve body control arrangement controls the second valve body to the second open position, the first valve body control arrangement controls the first valve body to the first closed position. In other words, only one of the first or second valve body can be in an open position at a time, and both valve bodies can be in the closed position at the same time.

[0019] Since only one of the first and second valve can be in the open position at a time, the fluid flow can only flow in either the first flow direction or the second flow direction so that the actuator can be controlled in either the first actuator direction or the second actuator direction.

[0020] The first valve body may be a cone valve or a seat valve having a substantially cylindrical shape. The second valve body may also be a cone valve or a seat valve having a substantially cylindrical shape. Each of the first valve body and the second valve body may further have a flat contact surface against the valve seat in the main valve house, as this allows lower demands on manufacturing tolerances with respect to the valves body's locations in the main valve house. These types of valve bodies are advantageous for applications where low leakage through the valve body in the closed position is required.

[0021] The first passage may be an annular cavity in the first valve body. The second passage and third passage may be annular cavities in the second valve body. The cavity of each of the passages may be an annular cut-out in the external surface of the respective valve body. The size of each cavity may be chosen depending on the required fluid flow rate and accepted pressure drop. By altering the depth in the radial direction, the intended fluid flow through the first and second valve bodies can be varied depending on required fluid flow. In the same way the cavity in the longitudinal direction can be altered depending on the required fluid flow. For example, a higher flow rate requires a bigger cavity in the radial direction and / or in the longitudinal direction.

[0022] The first valve body may further comprise a first flow channel fluidly connectable to the inlet port and a first pilot flow chamber. The first flow channel may be arranged to allow a first pilot flow between the inlet port and the first pilot flow chamber.

[0023] The first valve body control arrangement may comprise a first pilot stage valve assembly for controlling the pilot flow. The first valve body control arrangement may be arranged to continuously control the first valve body between the first open position and the first closed position. The valve arrangement further comprises a first pilot flow outlet, fluidly connectable to a first pilot flow channel. In this way, the first pilot flow channel is fluidly connectable to the second main outlet and a first pilot flow inlet fluidly connectable to the first pilot flow chamber.

[0024] The second valve body may further comprise a second flow channel fluidly connectable to the inlet port and a second pilot flow chamber. The second valve body may be arranged to allow a second pilot flow between the inlet port and the second pilot flow chamber.

[0025] The second valve body control arrangement may comprise a second pilot stage valve assembly for controlling the pilot flow. The second valve body control arrangement may be arranged to continuously control the second valve body between the second open position and the second closed position. The valve arrangement further comprises a second pilot flow outlet, fluidly connectable to a second pilot flow channel, wherein, the second pilot flow channel is fluidly connectable to the first main outlet and a second pilot flow inlet fluidly connectable to the second pilot flow chamber.

[0026] Each of the first valve body and the second valve body can be adapted with a gasket in order to further reduce the leakage between the valve arrangement and the first valve body and the second valve body, respectively.

[0027] In an example, the first pilot stage valve assembly may comprise a first electric actuator and a first pilot valve. The electric actuator can adjust the first pilot valve in order to control the position of the first valve body. The electric actuator may be connected to a control system circuit. By using a pilot valve, a small fluid flow in the first pilot flow channel may result in an amplified fluid flow in the second main outlet. In other words, the fluid flow in the first pilot flow channel multiplies the fluid flow in the second main outlet. The multiplication is usually a factor of ten, but other factors can also be used depending on the requirement of the application. For example, a fluid flow of 1 l / min in the first pilot flow results in a fluid flow of 10 l / min in the second main flow. Due to this function, a small movement in the first pilot valve results in a large fluid flow in the second main outlet. Thus, only a small displacement of the first pilot valve is needed, and it is not necessary to exert a large force on the first pilot valve. The size of the pilot valve may be reduced, which further enables the weight and size of the valve arrangement to be minimized. Since the pilot is of small dimensions, a smaller electric actuator can be used, thereby further minimizing the size and weight of the valve arrangement.

[0028] In an example, the second pilot stage valve assembly comprises a second electric actuator and a second pilot valve. The second electric actuator can adjust the second pilot valve in order to control the position of the second valve body. The electric actuator may be connected to a control system circuit portion. By using a pilot valve, a small fluid flow in the second pilot flow channel may result in an amplified fluid flow in the first main outlet. In other words, the fluid flow in the second pilot flow channel multiplies the fluid flow in the first main outlet. The multiplication is usually a factor of ten, but other factors can also be used depending on the requirement of the application. For example, a fluid flow of 1 l / min in the second pilot flow results in a fluid flow of 10 l / min in the first main flow. Due to this function, a small movement in the second pilot valve results in a large fluid flow in the first main outlet. Thus, only a small displacement of the second pilot valve is needed and it is not necessary to exert a large force on the second pilot valve. The size of the pilot valve may be reduced, which further enables the weight and size of the valve arrangement to be minimized. Since the pilot is of small dimensions, a smaller electric actuator can be used, thereby further minimizing the size and weight of the valve arrangement.

[0029] In an example, the valve arrangement comprises a first spring member of the valve arrangement which is associated with the first valve body. The first spring member is arranged to pretension the first valve body in the direction towards the first closed position. When the first pilot valve is closed, the first pilot flow is blocked. Since the first pilot flow is blocked, the pressure in the first pilot flow chamber increases. The pressure in the first pilot flow chamber pushes the first valve body in the direction towards the first closed position since the area of the first valve body that faces the first pilot flow chamber is larger than the area of the first vale body facing the inlet port. Together with the first spring member, the force towards the first closed position is greater than the force towards the first open position caused by the pressure from the inlet port.

[0030] In an example, the valve arrangement comprises a second spring member of the valve arrangement which is associated with the second valve body. The second spring member is arranged to pretension the second valve body in the direction towards the second closed position. When the second pilot valve is closed, the second pilot flow is blocked. Since the second pilot flow is blocked, the pressure in the second pilot flow chamber increases. The pressure in the second pilot flow chamber pushes the second valve body in the direction towards the second closed position since the area of the second valve body that faces the second pilot flow chamber is larger than the area of the second vale body facing the inlet port. Together with the second spring member, the force towards the second closed position is greater than the force towards the second open position caused by the pressure from the inlet port.

[0031] In an example, the inlet port is fluidly connectable to a fluid pump, such as a hydraulic pump or any other suitable pump.

[0032] In an example, the tank outlet is fluidly connectable to a fluid tank for storing fluid, such as a hydraulic fluid.

[0033] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure. Brief of the

[0034] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0035] Figure 1 shows a cross-sectional view of the valve arrangement according to an example of the present disclosure including one valve body enabling a unidirectional flow.

[0036] Figure 2 shows a cross-sectional view of the valve arrangement according to an example of the present disclosure, including two valve bodies, where both valve bodies are in their respective closed position.

[0037] Figure 3 shows a cross-sectional view of the valve arrangement of Figure 2, where the first valve body is in the first open position and the second valve body is in the second closed position.

[0038] Figure 4 shows a cross-sectional view of the valve arrangement of Figures 2 and 3where the first valve body is in the first closed position and the second valve body is in the second open position.

[0039] Figure 5 is a hydraulic diagram of the embodiment shown in Figures 2-4.

[0040] Detailed

[0041] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

[0042] Figure 1 shows a cross-sectional view of a valve arrangement 101 for controlling a hydraulic actuator M according to a first embodiment. The valve arrangement 101 comprises a main valve house 3, having an inlet port P, fluidly connectable to a fluid pump, and fluidly connectable to a first main outlet 2. The valve arrangement 101 further comprises a second main outlet 4 and a tank outlet T, fluidly connectable to a fluid tank. The first main outlet 2 and the second main outlet 4 are fluidly connectable to the actuator M allowing a direction of flow through the actuator M in a first flow direction in which the actuator M is controlled in a first actuator direction. The first flow direction is when the fluid flows from inlet port P to the second main outlet 4 through the actuator M to the first main outlet 2 and out through the tank outlet T. The valve arrangement 101 further comprises a first valve body 10, which is movable in the main valve house 3 between a first open position in which the inlet port P is in fluid connection with the second main outlet 4 allowing a flow in the first flow direction, and a first closed position in which the inlet port P is blocked from allowing a flow from the inlet port P to the second main outlet 4. A first valve body control arrangement of said valve arrangement 1 is arranged to control the position of the first valve body 10.

[0043] The first valve body 10 comprises a first passage 14, configured such that the first valve body 10 allows a fluid flow from the actuator M through the first main outlet 2 to the tank outlet T, when in the first open position. In the embodiment of Figure 1, the first valve body 10 further comprises a first flow channel 18 fluidly connectable to the inlet port P and a first pilot flow chamber 12.

[0044] In the embodiment shown in Figure 1, the first valve body control arrangement comprises a first pilot stage valve assembly 30 for controlling a pilot flow. The pilot flow is arranged to control the first valve body 10 between the first open position and the first closed position. The valve arrangement 101 may further comprise a first pilot flow outlet 31 which may be fluidly connectable to a first pilot flow channel 36 wherein the first pilot flow channel 36 may be fluidly connectable to the second main outlet 4 and a first pilot flow inlet 33 which may be fluidly connectable to the first pilot flow chamber 12.

[0045] The first pilot stage valve assembly 30 may further comprise a first electric actuator 32 and a first pilot valve 34

[0046] The first valve body 10 may be a cone valve or a seat valve having a substantially cylindrical shape.

[0047] The first passage 14 may be an annular cavity in the first valve body 10.

[0048] The valve arrangement 101 may further comprise a first spring member 11 which is associated with the first valve body 10, which pretensions the first valve body 10 in the direction towards the first closed position.

[0049] Figure 2 shows a cross-sectional view of a valve arrangement 1 for controlling the hydraulic actuator M according to a second embodiment. The valve arrangement 1 comprises a main valve house 3, having an inlet port P, fluidly connectable to a fluid pump, and fluidly connectable to a first main outlet 2, a second main outlet 4 and a tank outlet T, fluidly connectable to a fluid tank. The first main outlet 2 and the second main outlet 4 are fluidly connectable to the actuator M allowing a direction of flow through the actuator M in a first flow direction in which the actuator M is controlled in a first actuator direction or in a second flow direction which the actuator M is controlled in a second actuator direction. The first flow direction is when the fluid flows from inlet port P to the second main outlet 4 through the actuator M to the first main outlet 2 and out through the tank outlet T. The second flow direction is when the fluid flows from the inlet port P to the first main outlet 2 through the actuator M to the second main outlet and out through the tank outlet T. The valve arrangement 1 further comprises a first valve body 10, which is movable in the main valve house 3 between a first open position in which the inlet port P is in fluid connection with the second main outlet 4 allowing a flow in the first flow direction, and a first closed position in which the inlet port P is blocked from allowing a flow from the inlet port P to the second main outlet 4. The first valve body 10 may be controlled between the first closed position and the first open position by the first valve body control arrangement. The valve arrangement 1 comprises a second valve body 20, which is continuously movable in the main valve house 3 between a second open position in which the inlet port P is in fluid connection with the first main outlet 2 allowing a flow in the second flow direction and a second closed position in which the inlet port P is blocked from allowing a flow from the inlet port P to the first main outlet 2. The second valve body 20 may be controlled between the second closed position and the second open position by a second valve body control arrangement.

[0050] The first valve body control arrangement and the second valve body control arrangement are arranged to control the first and the second valve body 10, 20 in such a way that only one of the first valve body 10 and second valve body 20 can be in their respective open position at a time. Alternatively, both valve bodies can be in the closed position at the same time.

[0051] The first valve body 10 comprises a first passage 14, configured such that the first valve body 10 allows a fluid flow in the first flow direction, i.e. from the inlet port P to the second main outlet 4 through the actuator M to the first main outlet 2 and out through the tank outlet T, when in the first open position. The second valve body 20 comprises a second passage 23, configured such that the second valve body 20 allows a fluid flow in the first flow direction, i.e from the inlet port P to the second main outlet 4 through the actuator M to the first main outlet 2 and out through the tank outlet T, when in the second closed position. The second valve body 20 comprises a third passage 24, configured such that the second valve body 20 allows a fluid flow in the second flow direction, i.e. from the inlet port P to the first main outlet 2 through the actuator M to the second main outlet 4 and out through the tank outlet T, when in the second open position. The valve arrangement 1 may further comprise a first spring member 11 which is associated with the first valve body 10, which pretension the first valve body 10 in the direction towards the first closed position.

[0052] Figure 3 shows the first flow direction, marked by arrows in the figure. By controlling the first valve body 10 in the direction to the first open position a fluid starts to flow from the inlet port P through the second passage 23 in the second valve body 20 to the second main outlet 4, through the actuator M so that the actuator M is controlled in a first direction, to the first main outlet 2, through the first passage 14 in the first valve body 10 and out through the tank outlet T.

[0053] Figure 4 shows the second flow direction, marked by arrows in the figure. By controlling the second valve body 20 in the direction to the second open position a fluid starts to flow from the inlet port P to the first main outlet 2, through the actuator M so that the actuator M is controlled in the second direction, to the second outlet 4, through the third passage 24 in the second valve body 20 and out through the tank outlet T.

[0054] The first valve body 10 and the second valve body 20 may be cone valves or seat valves having a substantially cylindrical shape.

[0055] The first passage 14 may be an annular cavity in the first valve body 10. The second passage 23 and third passage 24 may be annular cavities in the second valve body 20.

[0056] The first valve body 10 further comprises a first flow channel 18 fluidly connectable to the inlet port P and a first pilot flow chamber 12, similar to the first valve body 10 described above for the first embodiment of Figure 1.

[0057] As in Figure 1, the first valve body control arrangement comprises a first pilot stage valve assembly 30 for controlling a pilot flow. The pilot flow is arranged to control the first valve body 10 between the first open position and the first closed position. The valve arrangement 1 further comprises a first pilot flow outlet 31 which may be fluidly connectable to a first pilot flow channel 36 wherein the first pilot flow channel 36 may be fluidly connectable to the second main outlet 4 and a first pilot flow inlet 33 which may be fluidly connectable to the first pilot flow chamber 12. The second valve body 20 further comprises a second flow channel 28 fluidly connectable to the inlet port P and a second pilot flow chamber 22.

[0058] In the embodiment shown in Figures 2-4, the second valve body control arrangement comprises a second pilot stage valve assembly 40 for controlling a pilot flow. The pilot flow is arranged to control the second valve body 20 between the second open position and the second closed position. The valve arrangement 1 may further comprise a second pilot flow outlet 41 fluidly connectable to a second pilot flow channel 46 wherein the second pilot flow channel 46 is fluidly connectable to the first main outlet 2 and a second pilot flow inlet 43 fluidly connectable to the second pilot flow chamber 22.

[0059] The first pilot stage valve assembly 30 may further comprise a first electric actuator 32 and a first pilot valve 34 and the second pilot stage valve assembly 40 may further comprise a second electric actuator 42 and a second pilot valve 44.

[0060] The valve arrangement 1 may further comprise a first spring member 11 which is associated with the first valve body 10, which pretensions the first valve body 10 in the direction towards the first closed position. When the first valve body control arrangement has controlled the first pilot valve 34 to a closed position, there will be a pressure equilibrium between the first pilot flow chamber 12 and the first flow channel 18, resulting in that the first valve body 10 will be controlled in the direction towards the first closed position with additional help of the first spring member 11, due to the fact that the area of the first valve body 10, facing the first pilot flow chamber 12 is larger than the area of the first valve body 10 facing the inlet port P. The valve arrangement 1 may further comprise a second spring member 21 which is associated with the second valve body 20, which pretensions the second valve body 20 in the direction towards the second closed position. When the second valve body control arrangement has controlled the second pilot valve 44 to a closed position, there will be a pressure equilibrium between the second pilot flow chamber 22 and the second flow channel 28, resulting in that the second valve body 20 will be controlled in the direction towards the second closed position with additional help of the second spring member 21, due to the fact that the area of the second valve body 20, facing the second pilot flow chamber 22 is larger than the area of the second valve body 20 facing the inlet port P.

[0061] In figure 2, the first valve body 10 is in the first closed position and the second valve body 20 is in the second closed position thereby preventing any fluid flow from the inlet port P. Figure 3 shows the same valve arrangement 1 as in figure 2, wherein the first valve body 10 is in the first open position and the second valve body 20 is in the second closed position.

[0062] Figure 3 shows that the first valve body control arrangement has controlled the first pilot valve 34 to an open position, thereby allowing a pilot flow from the first pilot flow chamber 12 to the second main outlet 4 via a first pilot flow channel 36.

[0063] When the first pilot valve 34 is controlled to an open position, the pressure in the first pilot flow chamber 12 will decrease causing the first valve body 10 to be controlled in the direction towards the first open position. A further increase of flow through the first pilot valve 34 will lead to a larger pressure drop in the first pilot flow chamber 12 causing the first valve body 10 to be controlled further in the direction towards the first open position.

[0064] Figure 4 shows the same valve arrangement 1 as in figure 2 and 3, wherein the first valve body 10 is in the first closed position and the second valve body 20 is in the second open position.

[0065] Figure 4 shows that the second valve body control arrangement has controlled the second pilot valve 44 to an open position, thereby allowing a pilot flow from the second pilot flow chamber 22 to the first main outlet 2 via a second pilot flow channel 46.

[0066] To control the second pilot valve 44 from the closed position to the open position, the pressure in the second pilot flow chamber 22 will decrease causing the second valve body 20 to be controlled in the direction towards the second open position. A further increase of flow though the second pilot valve 44 will lead to a larger pressure drop in the second pilot flow chamber 22 causing the second valve body 20 to be controlled further in the direction towards the second open position.

[0067] The first valve body control arrangement and the second valve body control arrangement are arranged to control the first and the second valve body 10, 20 in such a way that only one of the first valve body 10 and second valve body 20 can be in their respective open position at a time.

[0068] Figure 5 shows a hydraulic diagram of the second embodiment, shown in Figures 2-4, where the valve arrangement 1 can control the hydraulic actuator M in either a first direction or in a second direction. The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. A valve arrangement (1) for controlling a hydraulic actuator (M), the valve arrangement (1) comprising: a main valve house (3), having an inlet port (P) fluidly connectable to a first main outlet (2), a second main outlet (4) and a tank outlet (T), wherein the first main outlet (2) and the second main outlet (4) are fluidly connectable to the actuator (M) allowing a direction of flow through the actuator (M) in a first flow direction in which the actuator (M) is controlled in a first actuator direction; a first valve body (10), which is continuously movable in the main valve house (3) between a first open position in which the inlet port (P) is in fluid connection with the second main outlet (4) allowing a flow in the first flow direction, and a first closed position in which the inlet port (P) is blocked from allowing a flow from the inlet port (P) to the second main outlet (4), a first valve body control arrangement of said valve arrangement (1) is arranged to control the position of the first valve body (10); characterized in that the first valve body (10) comprises a first passage (14), configured such that the first valve body (10) allows a fluid flow from the actuator (M) through the first main outlet (2) to the tank outlet (T), when in the first open position.

2. The valve arrangement (1) according to claim 1, wherein the first valve body (10) is a cone valve having a substantially cylindrical shape.

3. The valve arrangement (1) to any of the preceding claims, wherein the first passage (14) is an annular cavity in the first valve body (10).

4. The valve arrangement (1) according to any of the preceding claims, wherein the first valve body (10) further comprises a first flow channel (18) fluidly connectable to the inlet port (P) and a first pilot flow chamber (12).

5. The valve arrangement (1) according to any of the preceding claims, wherein the first valve body control arrangement comprises a first pilot stage valve assembly (30) for controlling a first pilot flow, arranged to control the first valve body (10) between the first open position and the first closed position, the valve arrangement (1) further comprising a first pilot flow outlet (31) fluidly connectable to a first pilot flow channel (36) wherein the first pilot flow channel (36) is fluidly connectable to the second main outlet (4) and a first pilot flow inlet (33) fluidly connectable to the first pilot flow chamber (12).

6. The valve arrangement (1) according to claim 5, wherein the first pilot stage valve assembly (30) comprises a first electric actuator (32) and a first pilot valve (34).

7. The valve arrangement (1) according to any of the preceding claims, wherein a first spring member (11) of the valve arrangement (1) is associated with the first valve body (10), which pretension the first valve body (10) in the direction towards the closed position.

8. The valve arrangement (1) according to any of the preceding claims, wherein the main valve house (3) further allowing a direction of flow through the actuator (M) in a second flow direction which the actuator (M) is controlled in a second actuator direction and wherein the valve arrangement (1) further comprises: a second valve body (20), which is continuously movable in the main valve house (3) between a second open position in which the inlet port (P) is in fluid connection with the first main outlet (2) allowing a flow in the second flow direction, and a second closed position in which the inlet port (P) is blocked from allowing a flow from the inlet port (P) to the first main outlet (2), a second valve body control arrangement (40) of said valve arrangement (1) is arranged to control the position of the second valve body (20); wherein the second valve body (20) comprises a second passage (23), configured such that the second valve body (20) allows a fluid flow from the inlet port (P) to the actuator (M), when the second valve body (20) is in the second closed position and the and first valve body (10) is in the first open position; the second valve body (20) comprises a third passage (24), configured such that the second valve body (20) allows a fluid flow from the actuator (M) through the second main outlet (4) to the tank outlet (T) when the second valve body (20) is in the second open position.

9. The valve arrangement (1) according to claim 8, wherein the second valve body (20) is a cone valve having a substantially cylindrical shape.

10. The valve arrangement (1) according to any of claims 8-9, wherein the second passage (23) and third passage (24) is an annular cavity in the second valve body (20).

11. The valve arrangement (1) according to any of claims 8-10, wherein the second valve body (20) further comprises a second flow channel (28) fluidly connectable to the inlet port (P) and a second pilot flow chamber (22).

12. The valve arrangement (1) according to any of claims 8-11, wherein the second valve body control arrangement comprises a second pilot stage valve assembly (40) for controlling a second pilot flow, arranged to control the second valve body (20) between the second open position and the second closed position, the valve arrangement (1) further comprising a second pilot flow outlet (41) fluidly connectable to a second pilot flow channel(46) wherein the second pilot flow channel (46) is fluidly connectable to the first main outlet (2) and a second pilot flow inlet (43) fluidly connectable to the second pilot flow chamber (22).

13. The valve arrangement (1) according to any of claim 12, wherein the second pilot stage valve assembly (40) comprises a second electric actuator (42) and a second pilot valve (44).

14. The valve arrangement (1) according to any of claims 8-13, wherein a second spring member (21) of the valve arrangement (1) is associated with the second valve body (20), which pretension the second valve body (20) in the direction towards the closed position.

15. The valve arrangement (1) according to any of claims 8-14, wherein first valve body control arrangement and the second valve body control arrangement are arranged to control the first and the second valve body (10,20) in such a way that only one of the first valve body (10) and second valve body (20) can be in their respective open position at a time.

16. The valve arrangement (1) according to any of the preceding claims, wherein the inlet port (P) is fluidly connectable to a fluid pump.

17. The valve arrangement (1) according to any of the preceding claims, wherein the tank outlet (T) is fluidly connectable to a fluid tank for storing fluid.

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