HYDRAULIC VALVE DEVICE

Abstract

To efficiently regenerate the oil discharged from a rod chamber while suppressing any increase in size without creating a situation where the operating speed of a hydraulic cylinder for an arm deteriorates, a valve body 31 encloses a first valve hole 34, which accommodates a first valve 32, and a second valve hole 35, which accommodates a second valve 33. The second valve hole 35 encloses a regeneration port 35d. A regenerated oil path 45, which allows oil to flow from the regeneration port 35d to the bottom oil path 41, is arranged between the regeneration port 35d and the bottom oil path 41. The second counter outlet port 35c is connected to the regeneration port 35d when oil is discharged from the rod chamber 11a.The second meter outlet port 35c is connected to the second tank port 35e when the pressure at the rod chamber 11a becomes equal to or less than the pressure at the bottom chamber 11b.

Description

TECHNICAL AREA

[0001] The present invention relates to a hydraulic valve device that actuates an arm of a working machine in the lifting and tipping direction by controlling the oil supply to a rod chamber and a bottom chamber of a hydraulic cylinder for an arm. STATE OF THE ART

[0002] This type of hydraulic valve device regenerates the oil discharged from the rod chamber and supplies the regenerated oil to the bottom chamber when an actuating rod of the hydraulic cylinder for an arm is extended (during retraction). To regenerate the oil for the bottom chamber, it is preferable to reduce the amount of oil transferred to a tank. However, if the flow path from the bottom chamber to the tank is merely constricted, the actuating rod cannot be extended quickly if the oil is not regenerated. Prior art provides a technique for solving the problem described above, in which the oil passage is constricted at the time of oil regeneration, and an oil path with a relief valve is provided at a section between the rod chamber and the tank (see, for example, patent document 1). LIST OF COUNTERPOINTS Patent Literature

[0003] Patent Document 1: JP-A-2019-2531 BRIEF DESCRIPTION OF THE INVENTION Technical Problem

[0004] However, if the oil path including the relief valve is provided, the number of components may increase and the size of the hydraulic valve device may increase.

[0005] The present invention was realized taking into account the circumstances described above and has the objective of providing a hydraulic valve device that enables efficient regeneration of the oil discharged from a rod chamber while simultaneously suppressing an increase in its size without creating a situation in which the operating speed of the hydraulic cylinder for an arm deteriorates. Solution to the problem

[0006] To solve the problem described above, a hydraulic valve device according to one embodiment of the present invention is a hydraulic valve device that actuates an arm of a working machine in the lifting and tipping direction by supplying oil from a hydraulic pump to a bottom chamber and a rod chamber of a hydraulic cylinder for an arm. A valve body includes a first slide valve configured to control the oil supply to the bottom chamber and a second slide valve configured to control the oil supply to the rod chamber. A first slide valve orifice, which receives the first slide valve, includes a first pump oil supply port to be connected to the hydraulic pump, a first meter inlet port and a first meter outlet port to be connected to the bottom chamber via a lower oil path, and a first tank port to be connected to a tank.A second valve hole, accommodating the second valve, includes a second pump oil supply port to be connected to the hydraulic pump, a second meter inlet port and a second meter outlet port to be connected to the rod chamber via a rod oil path, and a second tank port to be connected to the tank. The second valve hole also includes a regeneration port, with a regenerated oil path, which allows oil to flow from the regeneration port to the lower oil path, located between the regeneration port and the bottom oil path. The second meter outlet port is connected to the regeneration port when oil is discharged from the rod chamber.The second meter outlet connection is connected to the second tank connection if the flow of oil from the regeneration connection to the lower oil path is not possible depending on the pressure at the rod chamber and the pressure at the bottom chamber. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] In one embodiment of the present invention, oil discharged from the rod chamber is fed to the bottom chamber via the regeneration port and the regenerated oil path when oil regeneration is possible. The slide valve moves to transfer the oil discharged from the rod chamber into the tank through the second meter outlet port when oil regeneration is not possible. This allows for efficient oil regeneration while preventing a reduction in the operating speed of the hydraulic cylinder for an arm without other components, such as a relief valve. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a cross-sectional view illustrating a hydraulic drive circuit to which a hydraulic valve device according to an embodiment of the present invention is applied, and also illustrating a state in which a slide valve is arranged in a neutral position. Fig. 2 is a diagram that shows the in Fig. 1 illustrated hydraulic drive circuit illustrated. Fig. Figure 3 is a side view of a working machine including a hydraulic cylinder connected to the Fig. The hydraulic drive circuit shown in section 1 is controlled. Fig. 4 is a cross-sectional view illustrating a state in which the slide gate is in a middle position in an excavation direction in the Fig. The hydraulic drive circuit is arranged as illustrated in 1. Fig. 5 is a diagram that shows the in Fig. 4 illustrated hydraulic drive circuits are shown. Fig. Figure 6 is a cross-sectional view illustrating a state in which the slide is in a full-stroke position in the excavation direction in the Fig. The hydraulic drive circuit is arranged as illustrated in 1. Fig. 7 is a diagram that shows the in Fig. 6 illustrated hydraulic drive circuits. Fig. Figure 8 is a graph showing the relationship between the stroke amount and the opening range of a counter outlet oil passage in a case where the slide valve is in the Fig. 1 illustrated hydraulic valve device is moved in the excavation direction. Fig. 9 is a cross-sectional view illustrating a state in which the slider is in the Fig. The hydraulic drive circuit shown in section 1 is moved in a tipping direction. Fig. 10 is a diagram that shows the in Fig. 9 illustrated hydraulic drive circuits are shown. DESCRIPTION OF EXECUTION FORMS

[0008] In the following, a preferred embodiment of a hydraulic valve device according to the present invention is described in detail with reference to the accompanying drawings.

[0009] Fig. 1 and Fig. Figure 2 illustrates a hydraulic drive circuit to which the hydraulic valve device according to the embodiment of the present invention is applied. Here, the hydraulic drive circuit illustrated as an example is a circuit used to operate the hydraulic cylinder 10 for an arm with oil from a hydraulic pump 1. The hydraulic pump 1 is a variable displacement pump driven by a motor 2 to change the tilt angle of a swashplate or an angled shaft, thereby varying the stroke volume. The hydraulic cylinder 10 for an arm is a single-rod, double-stroke cylinder used to actuate an arm AM provided in the working machine relative to a boom BM, as shown in Figure 2. Fig. Figure 3 illustrates this. The arm AM is rotatably supported by an arm shaft S, which extends horizontally through a base end section at a distal end section of a boom BM. When the hydraulic cylinder 10 for an arm is actuated to extend an actuating rod 12 relative to the cylinder body 11, the arm AM operates in a direction (extension direction) in which it is pulled towards an upper rotating body JS. Furthermore, when the hydraulic cylinder 10 for an arm is actuated to cause the actuating rod 12 to retract relative to the cylinder body 11, the arm operates in a direction (dumping direction) in which it moves away from the upper rotating body JS.

[0010] In the hydraulic drive circuit, the hydraulic valve device is provided between the hydraulic pump 1 and the hydraulic cylinder 10 for one arm, as shown in the Fig. 1 and Fig. Figure 2 illustrates the hydraulic valve device, which includes an arm direction switching valve configured for selective coupling of the hydraulic pump 1 with the rod chamber 11a and the bottom chamber 11b of the hydraulic cylinder 10 for one arm, and includes two slides 32 and 33 in a valve body 31 and a control unit 100.

[0011] The slides 32 and 33 each have a column shape enclosing a plurality of web sections, each subdivided by an annular groove, and are arranged in individual slide holes 34 and 35 provided in the valve body 31, wherein the slides 32 and 33 have axial centers that are parallel to each other and can move along their respective axial center directions. For the sake of simplicity, the Fig. 2 slides arranged on the left as the first slide 32 and the one in Fig. The two slides arranged on the right are designated as the second slide 33.

[0012] In a first valve hole 34, which accommodates the first valve 32, there are a first pump oil supply port 34a, a first meter inlet port 34b, a first meter outlet port 34c and a first tank port 34d in this order viewed from the end position side, which are in Fig. 1 is arranged downwards. When the first slide 32 moves axially, the coupling state of the first pump oil supply port 34a and the first tank port 34d is switched relative to the first meter inlet port 34b and the first meter inlet port 34c. More precisely, in a case where the first slide 32 is arranged in a neutral position, both the first meter inlet port 34b and the first meter outlet port 34c are disconnected from the first pump oil supply port 34a and the first tank port 34d, as shown in the Fig. 1 and Fig. 2 illustrates. When the first slider 32 is in Fig. 1 from the neutral position downwards (in Fig. (2 to the right) moves the first meter inlet port 34b to the first pump oil supply port 34a, while the first meter outlet port 34c and the first tank port 34d remain separated, as shown in Fig. 4 and Fig. 5 illustrates. When the first slider 32 is in Fig. 1 from the neutral position upwards (in Fig. (2 to the left) moves the first meter inlet port 34b in the disconnected state, while the first meter outlet port 34c and the first tank port 34d are connected, as shown in Fig. 9 and Fig. 10 illustrated.

[0013] The first meter inlet port 34b and the first meter outlet port 34c are each connected via a bottom oil path 41 to the bottom chamber 11b of the hydraulic cylinder 10 for one arm. The first pump oil supply port 34a is connected via a supply oil channel 42 to the hydraulic pump 1, and the first tank port 34d is connected via a drain oil channel 43 to a tank T. A first pressure sensor P1, which detects the pressure at the bottom chamber 11b, is provided in the bottom oil path 41.

[0014] In the second valve hole 35 are a second pump oil supply connection 35a, a second meter inlet connection 35b, a second meter outlet connection 35c, a regeneration connection 35d and a second tank connection 35e in this order from the one in Fig. 1 downward-facing end section side provided. When the second slide 33 moves axially, the coupling state of the second pump oil supply port 35a, the regeneration port 35d, and the second tank port 35e is switched relative to the second meter inlet port 35b and the second meter outlet port 35c. More precisely, in a case where the second slide 33 is in a neutral position, both the second meter inlet port 35b and the second meter outlet port 35c are disconnected from the second pump oil supply port 35a, the regeneration port 35d, and the second tank port 35e, as shown in the Fig. 1 and Fig. 2 illustrates. When the second slider 33 is in Fig. 1 from the neutral position downwards (in Fig. (2 to the right) to reach a middle position (half-stroke position), the second meter outlet port 35c is connected to the regeneration port 35d, while the second tank port 35e, the second meter inlet port 35b and the second pump oil supply port 35a remain separated, as shown in the Fig. 4 and Fig. Figure 5 illustrates this. When the second slide 33 moves in the same direction to reach a full-stroke position, the second meter inlet port 35b and the second pump oil supply port 35a remain in the disconnected state, while the second meter outlet port 35c moves into a state in which it is connected to the regeneration port 35d and the second tank port 35e, as shown in the Fig. 6 and Fig. Figure 7 illustrates this. When the second slider 33 is in Fig. 1 from the neutral position upwards (in Fig. (2 to the left) moves, the second meter outlet port 35c retains its separate state, the second meter inlet port 35b and the second pump oil supply port 35a are connected to each other, and the regeneration port 35d enters a state in which it is connected to the second tank port 35e, as shown in the Fig. 9 and Fig. 10 illustrated.

[0015] The second counter inlet port 35b and the second counter outlet port 35c are each connected to the rod chamber 11a of the hydraulic cylinder 10 for one arm via a rod oil path 44. The regeneration port 35d of the second valve hole 35 is connected to the bottom oil path 41 via a regeneration oil path 45. The regeneration oil path 45 includes a pilot check valve 46, which functions such that oil can only flow from the regeneration port 35d to the bottom oil path 41 when no pilot pressure is applied. When pilot pressure is applied, this pilot check valve 46 allows oil to flow from the bottom oil path 41 to the regeneration port 35d. A second pressure sensor P2, which detects the pressure at the rod chamber 11a, is provided in the rod oil path 44.

[0016] The two slides 32 and 33 each enclose a neutral spring 47 and also enclose corresponding pressure chambers 32A, 32B, 33A, 33B at corresponding end sections of each slide. The neutral spring 47 is used to hold the slides 32 and 33 in their neutral positions. Pressure chambers 32A and 32B each accommodate an end section of the first slide 32 and are filled with oil. Pressure chambers 33A and 33B each accommodate an end section of the second slide 33 and are filled with oil. Pressure chambers 32A and 32B are individually connected to pilot oil channels 51A and 51B, which are configured to provide a pilot pressure output from the actuating valves 50A and 50B. The pressure chambers 33A and 33B are individually connected to the pilot oil channels 53A and 53B, which are configured to provide the function of a pilot pressure output from the actuating valves 52A and 52B.Actuating valves 50A and 50B are valves operated by a control signal output from a control unit / operating lever 100, which will be described later in connection with the actuation of an operating lever (electric lever) 54. When a pilot pressure output from the actuating valves 50A and 50B is alternately applied to the pressure chambers 32A and 32B via the pilot oil channels 51A and 51B, it is possible to counteract the spring force of the neutral spring 47 to move the first spool 32. When the pilot pressure applied to the pressure chambers 32A and 32B is removed, the first spool 32 returns to the neutral position due to the spring force of the neutral spring 47.Similarly, it is possible to resist the spring force of the neutral spring 47 to move the second slide 33 when a pilot pressure output from the actuating valves 52A and 52B is alternately applied to the pressure chambers 33A and 33B via the pilot oil channels 53A and 53B. When the pilot pressure applied to the pressure chambers 33A and 33B is removed, the second slide 33 returns to the neutral position due to the spring force of the neutral spring 47. In the present embodiment, the pilot oil channel 53B, which is connected to the pressure chamber 33B provided to the right of the second slide 33 in the drawing, is connected to a split pilot oil channel 55 configured to apply a pilot pressure to the pilot check valve 46 described above.

[0017] The control unit 100 is configured to output a control signal to the actuating valves 50A, 50B, 52A and 52B according to the handling state of the operating lever 54 and the pressure state of the hydraulic cylinder 10 for an arm output by the two pressure sensors P1 and P2.

[0018] Assuming that the operating lever 54 is in the neutral position, the control unit 100 outputs a control signal to prevent any pilot pressure from being supplied to the actuating valves 50A, 50B, 52A, and 52B. This results in a state where the two slide valves 32 and 33 are each in the neutral position. Consequently, no oil flows to the rod chamber 11a and the bottom chamber 11b of the hydraulic cylinder 10 for one arm. Furthermore, the actuating rod 12 maintains its current position relative to the cylinder body 11.

[0019] When the operating lever 54 is actuated in the excavation direction in this state, the control unit 100 outputs a control signal to the actuating valves 50A, 50B, 52A and 52B, so that the first slide 32 and the second slide 33 move into Fig. 2 each to the right (in Fig. (1 downwards). That is, the control unit 100 applies a pilot pressure to each of the pressure chambers 32A (pressure chamber 32A in Fig. 1 arranged upwards) to the left of the first slide 32 in Fig. 2 and pressure chamber 33A (pressure chamber 33A in Fig. 1 arranged upwards) to the left of the second slide 33, causing both the first slide 32 and the second slide 33 to be in Fig. 2 move to the right. At this point, the control unit 100 retrieves the output from the first pressure sensor P1 and the second pressure sensor P2 and controls the position of the second slide 33 according to the Fig. 8 shown in the graph. In a case where the pressure detected by the second pressure sensor P2 exceeds the pressure detected by the first pressure sensor P1, for example when the arm AM and the bucket of the working machine are actuated in mid-air, the control unit 100 outputs a control signal to the actuating valves 52A and 52B, so that the second slide 33 stops in the middle position described above.

[0020] When the first slide 32 moves to the right and the second slide 33 moves to the middle position, oil from the hydraulic pump 1 is supplied through the supply oil channel 42, the first pump oil supply port 34a, the first meter inlet port 34b and the bottom oil path 41 into the bottom chamber 11b of the hydraulic cylinder 10 for one arm, as shown in the Fig. 4 and Fig. Figure 5 illustrates this. Simultaneously, all the oil discharged from the rod chamber 11a is fed to the bottom oil path 41 via the rod oil path 44, the second meter outlet port 35c, the regeneration port 35d, and the regenerated oil path 45. This means that all the oil discharged from the rod chamber 11a, together with the oil from the hydraulic pump 1, is fed to the bottom chamber 11b (oil regeneration). This allows the actuating rod 12 of the hydraulic cylinder 10 for an arm to be extended quickly, resulting in advantages such as the efficient execution of excavation work using the machine and improved energy consumption.

[0021] During the operation described above, the control unit 100 outputs a control signal to the actuating valves 52A and 52B to move the second slide 33 to the full-stroke position when the pressure detected by the second pressure sensor P2 is equal to or less than the pressure detected by the first pressure sensor P1. In this state, oil from the hydraulic pump 1 is supplied to the bottom chamber 11b of the hydraulic cylinder 10 for one arm via the supply oil channel 42, the first pump oil supply port 34a, the first counter inlet port 34b, and the bottom oil path 41. Simultaneously, the oil discharged from the rod chamber 11a is routed to the tank T via the rod oil path 44, the second counter outlet port 35c, the second tank port 35e, and the drain oil channel 43.This means that, in a situation where oil cannot be regenerated, the oil discharged from rod chamber 11a is returned to tank T without restriction, so there is no risk of impairing the operating speed of the actuating rod 12. This allows the hydraulic cylinder 10 for one arm to be actuated continuously and quickly, offering advantages such as the efficient execution of excavation work with the machine. Furthermore, the oil in the bottom chamber 11b can be returned to tank T simply by moving the second slide 33 from the middle position to the full-stroke position, thus eliminating the need for other components, such as a relief valve. Therefore, there is no risk of creating a situation that increases the number of components or necessitates a larger hydraulic valve assembly.

[0022] On the other hand, if the operating lever 54 is actuated from the neutral position in the tipping direction, the control unit 100 outputs a control signal to the actuating valves 50A, 50B, 52A and 52B, so that the first slide 32 and the second slide 33 each move in the left direction Fig. 2 move. That is, the control unit 100 supplies a pilot pressure to each of the pressure chambers 32B (pressure chamber 32B in Fig. 1 arranged downwards) to the right of the first slide 32 in Fig. 2 and pressure chamber 33B (pressure chamber 33B in Fig. 1 arranged downwards) to the right of the second slide 33, whereby the first slide 32 and the second slide 33 in Fig. 2 each move to the left.

[0023] When the first slide 32 and the second slide 33 are each moved to the left, oil from the hydraulic pump 1 flows through the supply oil channel 42, the second pump oil supply port 35a, the second counter inlet port 35b, and the rod oil path 44, as shown in the Fig. 9 and Fig. Figure 10 illustrates the supply of oil to the rod oil chamber 11a of the hydraulic cylinder 10 for an arm. Simultaneously, the oil discharged from the bottom chamber 11b is routed via the rod oil path 44, the first counter outlet port 34c, and the first tank port 34d to tank T. Furthermore, if a pilot pressure is output from the actuating valve 52B to the pressure chamber 33B, which is located to the right of the second slide valve 33, the pilot check valve 46 provided in the regenerated oil path 45 enters a state in which oil can flow from the bottom oil path 41 to the regeneration port 35d. In this configuration, oil from the bottom oil path 41 is also routed via the regenerated oil path 45, the regeneration port 35d, the second tank port 35e, and the drain oil channel 43 to tank T.In this way, it is possible to quickly retract the actuating rod 12 of the hydraulic cylinder 10 for an arm, which offers advantages such as the efficient execution of the tipping operation of the machine. Furthermore, the regeneration port 35d and the regenerated oil path 45 described above can be used to return the oil from the bottom chamber 11b to the tank T, thus eliminating the need for additional special parts or oil paths. Therefore, there is no risk of creating a situation that increases the number of components or necessitates a larger hydraulic valve assembly.

[0024] It should be noted that the embodiment described above is configured such that oil from the bottom chamber is also directed into the tank via the regenerated oil path when the hydraulic cylinder for an arm is operated in the tipping direction. However, the embodiment is not necessarily limited to this configuration. In this case, it is only necessary that the regenerated oil path be equipped with a check valve that allows oil to pass only from the regeneration port to the bottom oil path.

[0025] Furthermore, the embodiment described above is configured such that, if the pressure at the rod chamber is higher than the pressure at the bottom chamber, all the oil from the rod chamber is supplied to the bottom chamber when the first meter inlet port is connected to the first pump oil supply port. However, the present invention is not limited to this.

[0026] Furthermore, the embodiment described above is configured such that, when the first counter inlet port is connected to the first pump oil supply port, the pressure at the rod chamber and the pressure at the bottom chamber determines whether or not oil regeneration is possible. However, the present invention is not limited to this. For example, it is possible to use a configuration for the hydraulic cylinder 10 for an arm in which only the second slide 33 is located in Fig. 1 moved to the right when the first slide 32 is in the neutral position, and in a state in which the regeneration port 35d is connected to the second meter outlet port 35c, as shown in the Fig. 5 and Fig.As illustrated in Figure 7, the pressure at the rod chamber 11a and the pressure at the bottom chamber 11b determines whether oil regeneration is possible. Although in this case no oil is supplied from the hydraulic pump 1 to the hydraulic cylinder 10 for an arm, the oil discharged from the rod chamber 11a is supplied to the bottom chamber 11b via the regenerated oil path 45. Thus, in the working machine, the actuating rod 12 extends relative to the cylinder body 11 of the hydraulic cylinder 10 for an arm, making it possible to carry out the lifting operation of the arm AM. Reference symbol list 1 hydraulic pump 10 hydraulic cylinders for arm 11a Pole chamber 11b Bottom chamber 31 Valve bodies 32 First slider 33 Second slider 34 First valve hole 34a First pump oil supply connection 34b First meter inlet connection 34c First meter outlet connection 34d First tank connection 35 Second slide hole 35a Second pump oil supply connection 35b Second meter inlet connection 35c Second meter outlet connection 35d Regeneration connection 35e Second tank connection 41 Bodenölweg 44 Rod Oil Path 45 Regenerated Oilway 46 Pilot check valve AM Arm P1, P2 pressure sensor T Tank QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP-A-2019-2531

[0003]

Claims

[1] Hydraulic valve device which actuates an arm of a working machine to operate in excavation and dumping directions by supplying oil from a hydraulic pump to a bottom chamber and a rod chamber of a hydraulic cylinder for an arm, wherein a valve body comprising a first slide configured to control the oil supply to the bottom chamber and a second slide configured to control the oil supply to the rod chamber, comprising a first valve hole to accommodate the first valve, a first pump oil supply port to be connected to the hydraulic pump, a first counter inlet port and a first counter outlet port to be connected to the bottom chamber via a lower oil path, and a first tank port to be connected to a tank, a second valve hole to accommodate the second valve, a second pump oil supply port to connect to the hydraulic pump, a second counter inlet port and a second counter outlet port connected to the rod chamber via a rod oil path, and a second tank port connected to the tank, the second valve hole includes a regeneration port and a regenerated oil path, which allows oil to flow from the regeneration port to the bottom oil path, is arranged between the regeneration port and the bottom oil path, the second meter outlet connection is connected to the regeneration connection when oil is discharged from the rod chamber, and The second meter outlet connection is connected to the second tank connection if the flow of oil from the regeneration connection to the lower oil path is not possible depending on the pressure at the rod chamber and the pressure at the bottom chamber. [2] Hydraulic valve device according to claim 1, wherein the regenerated oil path is provided with a check valve which only allows oil to pass from the regeneration port to the lower oil path, provided that the pressure at the rod chamber is higher than the pressure at the bottom chamber. [3] Hydraulic valve device according to claim 1, wherein in a case where oil is discharged from the rod chamber, the second meter outlet port and the second tank port are separated from each other when the pressure at the rod chamber is higher than the pressure at the bottom chamber. [4] Hydraulic valve device according to claim 1, wherein the regeneration port is connected to the second tank port when the second meter inlet port is connected to the second pump oil supply port, and The regenerated oil path is equipped with a check valve that only allows oil to pass from the regeneration port to the bottom oil path during a normal condition, while it only allows oil to pass from the bottom oil path to the regeneration port when the first meter outlet port is connected to the first tank port and the second meter inlet port is connected to the second pump oil supply port. [5] Hydraulic valve device according to claim 1, wherein the second tank connection and the regeneration connection are arranged side by side in the second valve hole, in a case where the second valve moves from a neutral position in an excavation direction, the second meter outlet connection is connected to the regeneration connection in a state where the connection between the second meter outlet connection and the second tank connection is interrupted, and in a case where the second slide continues to move in the same direction, the second meter outlet is connected to the second tank connection. [6] Hydraulic valve device according to claim 1, comprising: a sensor configured to detect the pressure at the rod chamber; and a sensor configured to detect the pressure at the bottom chamber.

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