Hydraulic valve apparatus

Abstract

In order to achieve downsizing without impairing controllability, this hydraulic valve apparatus is configured such that: two spool holes 42, 43 of a valve body 41 are provided with pump oil supply ports 42a, 43a, meter-in ports 42c, 43c, meter-out ports 42d, 43d, and tank ports 42e, 43e; the meter-out port 43d is connected to the tank port 43e when the meter-in port 42c is connected to the pump oil supply port 42a; the meter-out port 42d is connected to the tank port 42e when the meter-in port 43c is connected to the pump oil supply port 43a; the spool holes 42, 43 are provided with communication ports 42b, 43b that are linked with each other via a communication oil passage 45; a spool 71 is provided with a linking groove part 71a that constantly links between the pump oil supply port 42a and the communication port 42b; and a spool 72 is provided with a blocking land 72a that constantly blocks between the pump oil supply port 43a and the communication port 43b.

Description

Hydraulic Valve Device

[0001] The present invention relates to a hydraulic valve device that controls the supply of oil to a hydraulic device using two independent spools for meter-in and meter-out.

[0002] Some hydraulic drive circuits use a hydraulic valve device that controls the supply of oil to hydraulic equipment such as a hydraulic cylinder using two independent spools for meter-in and meter-out. In this type of hydraulic valve device, one spool is connected to the rod chamber of the hydraulic cylinder, and the other spool is connected to the bottom chamber of the hydraulic cylinder. In a hydraulic drive circuit equipped with this hydraulic valve device, the hydraulic cylinder can be retracted by supplying oil to the hydraulic cylinder through one spool, and can be advanced by supplying oil to the hydraulic cylinder through the other spool (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-124642

[0004] Some hydraulic drive circuits are equipped with two oil supply passages to accommodate hydraulic equipment with large flow requirements. The two oil supply passages supply oil discharged from separate hydraulic pumps. The two oil supply passages are each formed in a straight line and arranged parallel to each other, thereby preventing the valve body from becoming too large.

[0005] Considering the controllability of the hydraulic devices, it is necessary to supply oil discharged from the same hydraulic pump to the rod chamber and the bottom chamber. In other words, as shown in Figures 10 and 11, the two spools A1 and A2 are preferably arranged side by side along the extension direction of the same oil supply passages C1 and C2. As shown in Figure 10, when the number of hydraulic devices D1, D2, D3, and D4 to be controlled is even, the two spools A1 and A2 can be arranged side by side along the extension direction of the respective oil supply passages C1 and C2, and the pairs of these two spools A1 and A2 can be adjacent to each other to save space in the hydraulic valve device. However, as shown in Figure 11, when the number of hydraulic devices D1, D2, and D3 to be controlled is odd, empty space is generated on the side of one of the oil supply passages C2 in the valve body E, which is not necessarily preferable in terms of miniaturization of the hydraulic valve device.

[0006] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a hydraulic valve device that can be made smaller without impairing controllability even when there are two oil supply passages.

[0007] In order to achieve the above object, the hydraulic valve device according to the present invention is provided with a valve body having a pair of spools for independently controlling meter-in and meter-out of a hydraulic device, and the two spool holes provided with the spools are each provided with a pump oil supply port connected to a hydraulic pump, a meter-in port and a meter-out port connected to the hydraulic device, and a tank port connected to a tank, and when one meter-in port of the two spool holes is connected to the pump oil supply port, the other meter-out port of the two spool holes is connected to the tank port; a spool operated so that a meter-out port of one of the two spool holes is connected to the tank port when the meter-out port of the other of the two spool holes is connected to the pump oil supply port; and the two spool holes are provided with communication ports that communicate with each other via communication oil passages provided in the valve body, and one of the two spools is configured to always communicate between the pump oil supply port and the communication port, while the other of the two spools is configured to always block communication between the pump oil supply port and the communication port.

[0008] According to the present invention, even when separate oil supply passages are connected to two spools, oil is always supplied to the hydraulic equipment from one of the oil supply passages. Therefore, two spools in a pair can be arranged side by side in a direction perpendicular to the extension direction of the oil supply passage, preventing the occurrence of wasted empty space.

[0009] FIG. 1 is a diagram showing a hydraulic drive circuit to which a hydraulic valve device according to an embodiment of the present invention is applied. FIG. 2 is a side view of a work machine equipped with hydraulic equipment controlled by the hydraulic drive circuit shown in FIG. 1. FIG. 3 is a diagram showing a schematic diagram of the hydraulic drive circuit shown in FIG. 1. FIG. 4 is a circuit diagram showing a bucket direction switching valve, which is a main component of the hydraulic drive circuit shown in FIG. 1, in a state where it is positioned in a neutral position. FIG. 5 is a cross-sectional view showing an example of the structure of the bucket direction switching valve shown in FIG. 4. FIG. 6 is a circuit diagram showing a state where the bucket direction switching valve shown in FIG. 4 is positioned in a retracted position. FIG. 7 is a cross-sectional view showing an example of the structure of the bucket direction switching valve shown in FIG. 6. FIG. 8 is a circuit diagram showing a state where the bucket direction switching valve shown in FIG. 4 is positioned in an advanced position. FIG. 9 is a cross-sectional view showing an example of the structure of the bucket direction switching valve shown in FIG. 8. FIG. 10 is a diagram showing a schematic diagram of a conventional hydraulic drive circuit that controls four hydraulic equipment. FIG. 11 is a diagram showing a schematic diagram of a conventional hydraulic drive circuit that controls three hydraulic equipment.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a hydraulic valve device according to the present invention will be described in detail below with reference to the accompanying drawings.

[0011] 1 shows a hydraulic drive circuit to which a hydraulic valve device according to an embodiment of the present invention is applied. The hydraulic drive circuit shown here is for driving three hydraulic cylinders 10, 20, and 30 with oil discharged from two hydraulic pumps 1A and 1B.

[0012] The hydraulic pumps 1A, 1B are variable displacement pumps whose displacement volume changes by changing the tilt angle of the swash plate or inclined axis. The hydraulic drive circuit of this embodiment uses two hydraulic pumps 1A, 1B having the same configuration and the same size. In the following, when distinguishing between the two, the one on the left side of Figure 1 will be referred to as the first hydraulic pump 1A and the one on the right side will be referred to as the second hydraulic pump 1B.

[0013] The hydraulic cylinders 10, 20, and 30 are double-acting, with the operating rods reciprocating relative to the cylinder bodies by selectively supplying oil to their respective rod chambers and bottom chambers. In this embodiment, as shown in FIG. 2 , the arm hydraulic cylinder 10, boom hydraulic cylinder 20, and bucket hydraulic cylinder 30 provided on one work machine are the targets of oil supply control. That is, the work machine shown in FIG. 2 includes a boom BM, an arm AM, and a bucket BK. The boom BM is rotatably supported at its base end on the upper rotating body JS by a horizontal boom shaft S1. The arm AM is rotatably supported at its base end on the tip of the boom BM by an arm shaft S2 provided parallel to the boom shaft S1. The bucket BK is rotatably supported at the tip of the arm AM by a bucket shaft S3 parallel to the arm shaft S2. The arm hydraulic cylinder 10 is interposed between the boom BM and the arm AM, the boom hydraulic cylinder 20 is interposed between the upper rotating body JS and the boom BM, and the bucket hydraulic cylinder 30 is interposed between the arm AM and the bucket BK. Each of the arm hydraulic cylinder 10, boom hydraulic cylinder 20, and bucket hydraulic cylinder 30 is a single-rod double-acting type equipped with a single operating rod.

[0014] As shown in Figure 1, the hydraulic drive circuit is provided with a hydraulic valve device 40 between hydraulic pumps 1A, 1B and hydraulic cylinders 10, 20, 30. The hydraulic valve device 40 has an arm direction switching valve 50 that selectively connects the hydraulic pump 1A to the rod chamber 11 and the bottom chamber 12 of the arm hydraulic cylinder 10, a boom direction switching valve 60 that selectively connects the hydraulic pump 1B to the rod chamber 21 and the bottom chamber 22 of the boom hydraulic cylinder 20, and a bucket direction switching valve 70 that selectively connects the hydraulic pump 1B to the rod chamber 31 and the bottom chamber 32 of the bucket hydraulic cylinder 30. In this hydraulic valve device 40, a valve body 41 is provided with two oil supply passages 2A, 2B, a tank oil passage 3, and six spools 51, 52, 61, 62, 71, 72.

[0015] The valve body 41 is a single block, and as shown in FIG. 3 , its external shape is a generally rectangular parallelepiped with its length extending vertically. The two oil supply passages 2A, 2B are linear cavities formed within the valve body 41 with the same inner diameter and extending parallel to each other. The two oil supply passages 2A, 2B are connected to the respective hydraulic pumps 1A, 1B, respectively, to supply oil. For convenience, the following description will refer to the two oil supply passages 2A, 2B as being arranged along the vertical direction of the valve body 41 and offset toward the rear of the valve body 41. When distinguishing between the two, the passage connected to the first hydraulic pump 1A will be referred to as the first oil supply passage 2A, and the passage connected to the second hydraulic pump 1B will be referred to as the second oil supply passage 2B. The tank oil passage 3 is a linear cavity formed within the valve body 41, and is arranged along the vertical direction of the valve body 41 and offset toward the front. The tank oil passage 3 is connected to the tank T.

[0016] The six spools 51, 52, 61, 62, 71, and 72 are arranged in pairs to control the supply of oil to one of the hydraulic cylinders 10, 20, and 30. As shown representatively in Figure 5, the spools 71 and 72 (51, 52, 61, and 62) are cylindrical with a plurality of lands divided by annular grooves, and are disposed in individual spool holes provided in the valve body 41 so as to be movable parallel to each other and along their respective axial directions with their axes perpendicular to the extension direction of the oil supply passages 2A and 2B.

[0017] 1 and 3, two spools (hereinafter referred to as arm spools 51, 52 when distinguished) that constitute the arm direction switching valve 50 and two spools (hereinafter referred to as boom spools 61, 62 when distinguished) that constitute the boom direction switching valve 60 are respectively disposed in the lower portion of the valve body 41. The two arm spools 51, 52 are arranged side by side above and below along the extension direction of the first oil supply passage 2A. The two boom spools 61, 62 are arranged side by side above and below along the extension direction of the second oil supply passage 2B. These two arm spools 51, 52 and two boom spools 61, 62 are arranged side by side on the left and right sides of each other.

[0018] 1 and 3, the arm spool 51 located at the upper left switches the connection state of a first pump oil supply port 51c and a tank port 51d to a first meter in port 51a and a first meter-out port 51b provided in the valve body 41. The first meter in port 51a and the first meter-out port 51b are each connected to the rod chamber 11 of the arm hydraulic cylinder 10 through a rod oil passage 53. A check valve 53a that allows oil to pass only to the rod chamber 11 is provided in the rod oil passage 53 from the first meter in port 51a to the rod chamber 11. The first pump oil supply port 51c is connected to the first oil supply passage 2A through a branch oil supply passage 54, and the tank port 51d is connected to the tank oil passage 3 through a drain oil passage 55.

[0019] 1 and 3, the arm spool 52 located at the lower left switches the connection states of the second pump oil supply port 52c and the tank port 52d to the second meter in port 52a and the second meter-out port 52b. The second meter in port 52a and the second meter-out port 52b are each connected to the bottom chamber 12 of the arm hydraulic cylinder 10 through a bottom oil passage 56. The bottom oil passage 56 extending from the second meter in port 52a to the bottom chamber 12 is provided with a check valve 56a that allows oil to pass only to the bottom chamber 12. The second pump oil supply port 52c is connected to the first oil supply passage 2A through a branch oil supply passage 54, and the tank port 52d is connected to the tank oil passage 3 through a drain oil passage 55.

[0020] 1 and 3, the boom spool 61, located at the upper right side, switches the connection states of the first pump oil supply port 61c and the tank port 61d to the first meter in port 61a and the first meter-out port 61b. The first meter in port 61a and the first meter-out port 61b are each connected to the rod chamber 21 of the boom hydraulic cylinder 20 via a rod oil passage 63. The rod oil passage 63 extending from the first meter in port 61a to the rod chamber 21 is provided with a check valve 63a that allows oil to pass only to the rod chamber 21. The first pump oil supply port 61c is connected to the second oil supply passage 2B via a branch oil supply passage 64, and the tank port 61d is connected to the tank oil passage 3 via a drain oil passage 65.

[0021] 1 and 3, the boom spool 62 located at the lower right side switches the connection states of the second pump oil supply port 62c and the tank port 62d to the second meter in port 62a and the second meter-out port 62b. The second meter in port 62a and the second meter-out port 62b are each connected to the bottom chamber 22 of the boom hydraulic cylinder 20 through a bottom oil passage 66. The bottom oil passage 66 extending from the second meter in port 62a to the bottom chamber 22 is provided with a check valve 66a that allows oil to pass only to the bottom chamber 22. The second pump oil supply port 62c is connected to the second oil supply passage 2B through a branch oil supply passage 64, and the tank port 62d is connected to the tank oil passage 3 through a drain oil passage 65.

[0022] Meanwhile, the two spools (hereinafter referred to as bucket spools 71, 72 when distinguished) that constitute bucket directional control valve 70 are arranged side by side on the left and right in the upper portion of valve body 41. That is, the bucket spool arranged on the right side in Figures 1 and 3 (hereinafter referred to as first bucket spool 71 when distinguished) is arranged side by side on an extension of the two boom spools 61, 62, and the bucket spool arranged on the left side (hereinafter referred to as second bucket spool 72 when distinguished) is arranged side by side on an extension of the two arm spools 51, 52.

[0023] The spool hole 42 of the valve body 41 that houses the first bucket spool 71 is provided with a first pump oil supply port (pump oil supply port) 42a, a first communication port (communication port) 42b, a first meter in port (meter in port) 42c, a first meter-out port (meter-out port) 42d, and a tank port 42e, in this order from the end located on the right side in FIG. 4 . When the first bucket spool 71 moves along the axial direction, the connection states of the first pump oil supply port 42a, the first communication port 42b, and the tank port 42e to the first meter in port 42c and the first meter-out port 42d are switched. During this time, the first pump oil supply port 42a and the first communication port 42b are always in communication with each other via a communication groove 71a provided in the first bucket spool 71.

[0024] More specifically, as shown in Figures 4 and 5, when the first bucket spool 71 is positioned in the neutral position, the first meter port 42c and the first meter-out port 42d are all blocked from the first pump oil supply port 42a, the first communication port 42b, and the tank port 42e. When the first bucket spool 71 moves to the left from the neutral position, as shown in Figures 6 and 7, the first meter port 42c is connected to the first pump oil supply port 42a via the first communication port 42b, while the first meter-out port 42d remains blocked. When the first bucket spool 71 moves to the right from the neutral position, as shown in Figures 8 and 9, the first meter port 42c remains blocked, while the first meter-out port 42d and the tank port 42e are connected.

[0025] The spool hole 43 of the valve body 41 that houses the second bucket spool 72 is provided with a second pump oil supply port (pump oil supply port) 43a, a second communication port (communication port) 43b, a second meter in port (meter in port) 43c, a second meter-out port (meter-out port) 43d, and a tank port 43e, in this order from the end located on the right side in FIG. 4 . When the second bucket spool 72 moves along the axial direction, the connection states of the second pump oil supply port 43a and the tank port 43e to the second meter in port 43c and the second meter-out port 43d are switched. During this time, the second pump oil supply port 43a and the second communication port 43b are constantly blocked from communication by a blocking land portion 72a provided on the second bucket spool 72.

[0026] More specifically, as shown in Figures 4 and 5, when the second bucket spool 72 is positioned in the neutral position, the second meter port 43c and the second meter-out port 43d are all blocked from the second pump oil supply port 43a, the second communication port 43b, and the tank port 43e. When the second bucket spool 72 moves to the left from the neutral position, as shown in Figures 6 and 7, the second meter port 43c remains blocked, while the second meter-out port 43d and the tank port 43e are connected. When the second bucket spool 72 moves to the right from the neutral position, as shown in Figures 8 and 9, the second meter port 43c is connected to the second communication port 43b, while the second pump oil supply port 43a and the second meter-out port 43d remain blocked.

[0027] The first pump oil supply port 42a is connected to the second oil supply passage 2B via a branch oil supply passage 44B, and the second pump oil supply port 43a is connected to the first oil supply passage 2A via a branch oil supply passage 44A. The first communication port 42b and the second communication port 43b are connected to each other via a communication oil passage 45 provided in the valve body 41. The first meter in port 42c and the first meter-out port 42d are each connected to the rod chamber 31 of the bucket hydraulic cylinder 30 via a rod oil passage 46. The rod oil passage 46 extending from the first meter in port 42c to the rod chamber 31 is provided with a check valve 46a that allows oil to pass only to the rod chamber 31. The second meter in port 43c and the second meter-out port 43d are each connected to the bottom chamber 32 of the bucket hydraulic cylinder 30 via a bottom oil passage 47. A bottom oil passage 47 extending from the second meter port 43c to the bottom chamber 32 is provided with a check valve 47a that allows oil to pass only to the bottom chamber 32. Each of the tank ports 42e, 43e is connected to the tank oil passage 3 through a drain oil passage 48.

[0028] As is clear from the figure, each of the six spools 51, 52, 61, 62, 71, and 72 is provided with a neutral spring 80 and pressure chambers 81 at both ends. The neutral springs 80 are used to maintain each of the spools 51, 52, 61, 62, 71, and 72 in a neutral position. The pressure chambers 81 accommodate the ends of the spools 51, 52, 61, 62, 71, and 72 and are filled with oil. Although not shown in the figure, each pressure chamber 81 is individually connected to a pilot oil passage for applying pilot pressure output from the operating valve. When the pilot pressure output in response to operation of the operation valve is applied to the pressure chamber 81 through the pilot oil passage, it presses the spools 51, 52, 61, 62, 71, and 72 in the axial direction, allowing the spools 51, 52, 61, 62, 71, and 72 to move against the spring force of the neutral spring 80. When the pilot pressure applied to the pressure chamber 81 is removed, the spring force of the neutral spring 80 returns the spools 51, 52, 61, 62, 71, and 72 to their neutral positions. In this embodiment, the arm operation valve is provided so that the two arm spools 51 and 52 move in the same direction. Similarly, when the boom operation valve is operated, the two boom spools 61 and 62 move in the same direction, and when the bucket operation valve is operated, the two bucket spools 71 and 72 move in the same direction.

[0029] In the hydraulic drive circuit configured as described above, when the arm spools 51, 52 are positioned in the neutral position, the first meter port 51a, the first meter-out port 51b, the second meter port 52a, and the second meter-out port 52b are all blocked, as shown in Figure 1. Therefore, no oil flows through the rod chamber 11 and the bottom chamber 12 of the arm hydraulic cylinder 10, and the operating rod 14 maintains its current position relative to the cylinder body 13.

[0030] 1 by operating the operating valve from this state, oil discharged from hydraulic pump 1A to first oil supply passage 2A is supplied to rod chamber 11 of arm hydraulic cylinder 10 through branch oil feed passage 54, first pump oil supply port 51c of arm spool 51, first meter port 51a, and rod oil passage 53. At the same time, oil in bottom chamber 12 is discharged to tank T through bottom oil passage 56, second meter-out port 52b of arm spool 52, tank port 52d, and drain oil passage 55. Therefore, in the work machine, operating rod 14 is retracted relative to cylinder body 13 of arm hydraulic cylinder 10, allowing dumping of arm AM.

[0031] Conversely, when the arm spools 51, 52 are moved to the right in Figure 1 by operation of the operating valve, oil discharged from the hydraulic pump 1A to the first oil supply passage 2A is supplied to the bottom chamber 12 of the arm hydraulic cylinder 10 through the branch oil feed passage 54, the second pump oil supply port 52c, the second meter port 52a, and the bottom oil passage 56. At the same time, oil in the rod chamber 11 is discharged to the tank T through the rod oil passage 53, the first meter-out port 51b, the tank port 51d, and the drain oil passage 55. Therefore, in the work machine, the operating rod 14 advances relative to the cylinder body 13 of the arm hydraulic cylinder 10, allowing the arm AM to perform an excavation operation.

[0032] Similarly, when the boom spools 61, 62 are disposed in the neutral position, the first meter port 61a, the first meter-out port 61b, the second meter port 62a, and the second meter-out port 62b are all blocked. Therefore, no oil flows through the rod chamber 21 and the bottom chamber 22 of the boom hydraulic cylinder 20, and the operating rod 24 maintains its current position relative to the cylinder body 23.

[0033] 1 by operating the operating valve from this state, oil discharged from hydraulic pump 1B to second oil supply passage 2B is supplied to rod chamber 21 of boom hydraulic cylinder 20 through branch oil feed passage 64, first pump oil supply port 61c of boom spool 61, first meter port 61a, and rod oil passage 63. At the same time, oil in bottom chamber 22 is discharged to tank T through bottom oil passage 66, second meter-out port 62b of boom spool 62, tank port 62d, and drain oil passage 65. Therefore, in the work machine, operating rod 24 is retracted relative to cylinder body 23 of boom hydraulic cylinder 20, allowing the boom BM to be lowered.

[0034] 1 by operation of the operating valve, oil discharged from hydraulic pump 1B to second oil supply passage 2B is supplied to bottom chamber 22 of boom hydraulic cylinder 20 through branch oil feed passage 64, second pump oil supply port 62c, second meter port 62a, and bottom oil passage 66. At the same time, oil in rod chamber 21 is discharged to tank T through rod oil passage 63, first meter-out port 61b, tank port 61d, and drain oil passage 65. Therefore, in the work machine, operating rod 24 advances relative to cylinder body 23 of boom hydraulic cylinder 20, allowing the boom BM to be raised.

[0035] On the other hand, when the bucket spools 71, 72 are disposed in the neutral position, the first communication port 42b and the second communication port 43b are communicated with each other through the communication oil passage 45, and these communication ports 42b, 43b are communicated with the first pump oil supply port 42a by the communication groove 71a, but the second pump oil supply port 43a, the first meter in port 42c, the first meter-out port 42d, the second meter in port 43c, the second meter-out port 43d, and the tank ports 42e, 43e are all blocked. Therefore, no oil flows through the bucket hydraulic cylinder 30, and the operating rod 34 maintains its current position relative to the cylinder body 33.

[0036] 1 by operating the operating valve from this state, oil discharged from second hydraulic pump 1B to second oil supply passage 2B is supplied to rod chamber 31 of bucket hydraulic cylinder 30 through branch oil feed passage 44B, first pump oil supply port 42a, communicating groove 71a, first communication port 42b, first meter port 42c, and rod oil passage 46. At the same time, oil in bottom chamber 32 is discharged to tank T through bottom oil passage 47, second meter-out port 43d, tank port 43e, and drain oil passage 48. Therefore, in the work machine, operating rod 34 is retracted relative to cylinder body 33 of bucket hydraulic cylinder 30, allowing the dump operation of bucket BK to be performed.

[0037] 1 by operation of the operating valve, oil discharged from second hydraulic pump 1B to second oil supply passage 2B is supplied to bottom chamber 32 of bucket hydraulic cylinder 30 through branch oil feed passage 44B, first pump oil supply port 42a, communicating groove 71a, first communication port 42b, communication oil passage 45, second communication port 43b, second meter port 43c, and bottom oil passage 47. At the same time, oil in rod chamber 31 is discharged to tank T through rod oil passage 46, first meter-out port 42d, tank port 42e, and drain oil passage 48. Therefore, in the work machine, operating rod 34 advances relative to cylinder body 33 of bucket hydraulic cylinder 30, allowing the bucket BK to perform an excavation operation.

[0038] During these operations, the hydraulic valve device 40 controls the oil supply to the arm hydraulic cylinder 10 using two arm spools 51 and 52. Similarly, the oil supply to the boom hydraulic cylinder 20 is controlled using two boom spools 61 and 62, and the oil supply to the bucket hydraulic cylinder 30 is controlled using two bucket spools 71 and 72. When the oil supply to the hydraulic cylinders 10, 20, and 30 is controlled using two spools each—in other words, when meter-in and meter-out are controlled using independent spools—it is possible to increase the outer diameter while keeping the axial dimension smaller than when a single spool is used. Therefore, it is possible to reduce pressure loss and supply more oil to each of the hydraulic cylinders 10, 20, and 30 without increasing the size of the hydraulic valve device 40. This allows the arm AM, boom BM, and bucket BK of the work machine to be operated faster and with greater force, while also improving fuel efficiency.

[0039] Moreover, the above-described hydraulic valve device 40 controls the supply of oil to the three hydraulic cylinders 10, 20, and 30, and the six spools 51, 52, 61, 62, 71, and 72 are arranged in a space-efficient manner in the valve body 41. That is, the arm spools 51 and 52 are arranged vertically in parallel along the extension direction of the first oil supply passage 2A, and the boom spools 61 and 62 are arranged vertically in parallel along the extension direction of the second oil supply passage 2B. Furthermore, with regard to the bucket spools 71 and 72, the first bucket spool 71 is arranged horizontally next to the boom spools 61 and 62, and the second bucket spool 72 is arranged horizontally next to the arm spools 51 and 52. Therefore, no wasted space is generated in the valve body 41, and the size can be reduced.

[0040] Furthermore, with regard to the arm hydraulic cylinder 10, the two arm spools 51, 52 are connected to the first oil supply passage 2A, and oil discharged from the first hydraulic pump 1A is supplied to the rod chamber 11 and the bottom chamber 12, respectively. Similarly, the two boom spools 61, 62 of the boom hydraulic cylinder 20 are connected to the second oil supply passage 2B, and oil discharged from the second hydraulic pump 1B is supplied to the rod chamber 21 and the bottom chamber 22, respectively. This is therefore advantageous in terms of controllability, such as smoother operation when extending and retracting the arm hydraulic cylinder 10 and the boom hydraulic cylinder 20, that is, when switching the oil supply direction.

[0041] On the other hand, for bucket hydraulic cylinder 30, two bucket spools 71, 72 are connected to individual oil supply passages 2A, 2B. However, only oil discharged from second hydraulic pump 1B is supplied to both rod chamber 31 and bottom chamber 32, and it is possible to ensure the same controllability as arm hydraulic cylinder 10 and boom hydraulic cylinder 20.

[0042] Furthermore, according to the hydraulic valve device 40 described above, even when the same valve body 41 is used, by interchanging the bucket spools 71, 72, it becomes possible to operate the bucket hydraulic cylinder 30 using only the oil discharged from the first hydraulic pump 1A. In other words, even when the same valve body is used, simply by changing the shape of the spool, it becomes possible to easily change the hydraulic pump that supplies oil to the hydraulic cylinder, which is extremely advantageous in terms of versatility.

[0043] In the above-described embodiment, the hydraulic valve device 40 is illustrated as being for operating the arm AM, boom BM, and bucket BK of the work machine, but the present invention is not limited to this. Also, although an example is given in which three hydraulic devices are operated, there is no need for there to be more than one hydraulic device, and the number of hydraulic devices does not necessarily have to be an odd number.

[0044] Furthermore, the hydraulic valve device 40 that operates the three hydraulic devices has two arm spools 51, 52 and two boom spools 61, 62 arranged side by side above and below each other, but by providing communication ports and communication oil passages in the valve bodies for the arm spools 51, 52 and the boom spools 61, 62 as with the bucket spools 71, 72, it is possible to arrange the respective spools 51, 52, 61, 62 side by side in a direction perpendicular to the extension direction of the oil supply passages 2A, 2B.

[0045] 1A, 1B Hydraulic pump 2A, 2B Oil supply passage 10 Arm hydraulic cylinder 20 Boom hydraulic cylinder 30 Bucket hydraulic cylinder 40 Hydraulic valve device 41 Valve body 42 Spool hole 42a First pump oil supply port 42b First communication port 42c First meter in port 42d First meter out port 42e Tank port 43 Spool hole 43a Second pump oil supply port 43b Second communication port 43c Second meter in port 43d Second meter out port 43e Tank port 45 Communication oil passage 71, 72 Bucket spool 71a Communication groove 72a Shutoff land AM Arm BK Bucket BM Boom

Claims

1. A hydraulic valve device in which a valve body is provided with a pair of spools that independently control meter-in and meter-out for hydraulic equipment, and the two spool holes in which the spools are provided are each provided with a pump oil supply port connected to a hydraulic pump, a meter-in port and a meter-out port connected to the hydraulic equipment, and a tank port connected to a tank, and each spool is operated so that when the meter-in port of one of the two spool holes is connected to the pump oil supply port, the meter-out port of the other of the two spool holes is connected to the tank port, and when the meter-in port of the other of the two spool holes is connected to the pump oil supply port, the meter-out port of one of the two spool holes is connected to the tank port, and the two spool holes are provided with communication ports that communicate with each other via a communication oil passage provided in the valve body, and one of the two spools is formed so as to constantly communicate between the pump oil supply port and the communication port, while the other of the two spools is formed so as to constantly block communication between the pump oil supply port and the communication port.

2. A hydraulic valve device as described in claim 1, characterized in that one of the two spools is provided with a communication groove portion that constantly connects the pump oil supply port and the communication port, and the other of the two spools is provided with a blocking land portion that constantly blocks the communication between the pump oil supply port and the communication port.

3. The hydraulic valve device according to claim 1, characterized in that the pump oil supply port provided in one of the two spool holes is connected to a first hydraulic pump through a first oil supply passage, and the pump oil supply port provided in the other of the two spool holes is connected to a second hydraulic pump through a second oil supply passage.

4. The hydraulic valve device according to claim 3, characterized in that the valve body is provided with three sets of spools for controlling the supply of oil to three hydraulic devices, the three sets of spools being arranged with their axes parallel to each other and perpendicular to the extending direction of the first oil supply passage and the second oil supply passage, a first set of the three sets of spools being arranged side by side along the extending direction of the first oil supply passage, a second set of the three sets of spools being arranged side by side along the second oil supply passage, and a third set of the three sets of spools being arranged side by side along a direction perpendicular to the extending direction of the first oil supply passage and the second oil supply passage.

5. The hydraulic valve device according to claim 4, characterized in that the three hydraulic devices are an arm hydraulic cylinder for operating the arm of a work machine, a boom hydraulic cylinder for operating the boom, and a bucket hydraulic cylinder for operating the bucket, wherein two spools for controlling the supply of oil to the arm hydraulic cylinder are arranged side by side along the extension direction of the first oil supply passage, two spools for controlling the supply of oil to the boom hydraulic cylinder are arranged side by side along the extension direction of the second oil supply passage, and two spools for controlling the supply of oil to the bucket hydraulic cylinder are arranged side by side in a direction perpendicular to the extension directions of the first oil supply passage and the second oil supply passage.

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