Valve device

Abstract

To provide a valve device that can be fitted with a pressure gage for detecting a supply pressure to a hydraulic actuator or a discharge pressure from the hydraulic actuator.SOLUTION: A valve device according to an embodiment includes a spool 6 and a housing 2. The housing 2 includes a spool hole into which the spool 6 is inserted, a sensor port 32 on a surface of the housing 2, a first actuator port 31a, and a second actuator port 31b. The housing 2 also includes a first actuator passage 81 leading to the first actuator port 31a from the spool hole, a second actuator passage 82 leading to the second actuator port 31b from the spool hole, and a sensor passage 34 making the first actuator passage 81 and the sensor port 32 communicate with each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a valve device interposed between a hydraulic pump and a hydraulic actuator in a hydraulic circuit. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a valve device is used in a hydraulic circuit to control the supply and discharge of hydraulic oil to and from a hydraulic actuator. The valve device includes a spool and a housing that slidably holds the spool.

[0003] For example, Patent Document 1 discloses a valve gear in which a plurality of spools are held in a row in a housing, and a pair of actuator ports is provided for each spool on one side of the housing that faces in a direction perpendicular to the side on which the spools are arranged. In Patent Document 1, the housing is called a "main body block." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-190044 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, when detecting the supply pressure of hydraulic oil to a hydraulic actuator or the discharge pressure from the hydraulic actuator, a pressure gauge is provided in the hydraulic oil piping between the valve device and the hydraulic actuator. However, there is a demand for a pressure gauge that detects the supply pressure to the hydraulic actuator or the discharge pressure from the hydraulic actuator, which is attached to the valve device.

[0006] Therefore, an object of the present disclosure is to provide a valve device to which a pressure gauge can be attached for detecting the supply pressure to a hydraulic actuator or the discharge pressure from the hydraulic actuator. [Means for solving the problem]

[0007] The present disclosure provides a valve device comprising a spool and a housing that slidably holds the spool, the housing including a spool hole into which the spool is inserted, a sensor port on a surface of the housing, a first actuator port and a second actuator port, a first actuator passage extending from the spool hole to the first actuator port, a second actuator passage extending from the spool hole to the second actuator port, and a sensor passage communicating between the first actuator passage and the sensor port. Effect of the Invention

[0008] According to the present disclosure, a valve device is provided that can be fitted with a pressure gauge that detects the supply pressure to a hydraulic actuator or the discharge pressure from the hydraulic actuator. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a valve device according to an embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a circuit diagram of a portion of the valve device. [Figure 4] FIG. 11 is a circuit diagram of a portion of a valve device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] FIG. 1 shows a valve device 1 according to one embodiment. In this embodiment, the valve device 1 is used for a plurality of hydraulic actuators 7. See FIG. 3 for the hydraulic actuators 7. That is, the valve device 1 is interposed between a hydraulic pump and the plurality of hydraulic actuators 7 in a hydraulic circuit. However, the valve device 1 may be used for a single hydraulic actuator 7.

[0011] 3, the hydraulic actuator 7 includes a hydraulic cylinder 7A that drives an object to be driven in the direction of gravity and the direction against gravity. The hydraulic cylinder 7A includes a first working chamber 71 to which hydraulic oil is supplied when the object to be driven is driven in the direction against gravity, and a second working chamber 72 to which hydraulic oil is supplied when the object to be driven is driven in the direction of gravity. In this embodiment, the rod side chamber is the first working chamber 71 and the head side chamber is the second working chamber 72, but the head side chamber may be the first working chamber 71 and the rod side chamber may be the second working chamber 72, opposite to this embodiment.

[0012] The gravity direction and antigravity direction do not necessarily have to be vertical, and may be oblique to the vertical. Alternatively, when the object to be driven swings around a horizontal axis, the gravity direction and antigravity direction may be circumferential directions about the horizontal axis. For example, when the valve device 1 is mounted on a hydraulic excavator, the hydraulic cylinder 7A is a boom cylinder or an arm cylinder. The boom cylinder lifts or lowers the boom, which is the object to be driven, and the arm cylinder swings the arm, which is the object to be driven.

[0013] 1 and 2, the valve device 1 includes spools 6, the number of which is the same as the number of hydraulic actuators 7, and a housing 2 that slidably holds the spools 6. In this embodiment, the number of spools 6 is six. However, the number of spools 6 may be one or more and five or less, or seven or more.

[0014] 2, in the present embodiment, the spool 6A corresponding to the hydraulic cylinder 7A among the spools 6 is divided into a first spool 61 and a second spool 62. The first spool 61 and the second spool 62 are positioned on the same axis, with the outer end faces of the first spool 61 and the second spool 62 facing in opposite directions, and the inner end faces of the first spool 61 and the second spool 62 facing each other. The five spools 6 other than the spool 6A are integral and extend across two cross passages 16 of the tank passage 15, which will be described later.

[0015] In this embodiment, the spools 6 are arranged in a single row and held in the housing 2. However, the spools 6 may be arranged in two rows and held in the housing 2.

[0016] The housing 2 is substantially rectangular and includes a first side surface 21 and a second side surface 22 that face opposite each other along the axial direction of the spool 6, a third side surface 23 and a fourth side surface 24 that face opposite each other along a direction perpendicular to the axial direction and arrangement direction of the spool 6, and a first end surface 25 and a second end surface 26 that face opposite each other along the arrangement direction of the spool 6. The first side surface 21, the second side surface 22, the third side surface 23, the fourth side surface 24, the first end surface 25 and the second end surface 26 constitute the surfaces of the housing 2.

[0017] The housing 2 also includes a plurality of spool holes 20 into which the spools 6 are respectively inserted. Each spool hole 20 penetrates the housing 2 and opens to a first side surface 21 and a second side surface 22.

[0018] In this embodiment, a pump port and a tank port are formed on the fourth side surface 24 of the housing 2. The pump port is connected to the hydraulic pump by a pipe, and the tank port is connected to the tank by a pipe. However, the pump port and the tank port may be formed on the first end surface 25 or the second end surface 26.

[0019] The housing 2 is provided with a pump passage 11 extending from the pump port to all of the spool holes 20, and a tank passage 15 extending from all of the spool holes 20 to the tank port. The pump passage 11 includes a transverse passage 12 extending in the arrangement direction of the spools 6 near the center of the spool hole 20, an inlet passage connecting the transverse passage 12 to the pump port, and a plurality of distribution passages 13 connecting each of the transverse passages 12 to the spool hole 20. The distribution passage 13 is provided with a check valve 14. The tank passage 15 includes two transverse passages 16 that extend in the arrangement direction of the spools 6 so as to pass through both ends of the spool hole 20, and an outflow passage that connects the transverse passages 16 with the tank port.

[0020] A pair of actuator ports 31 are formed for each spool 6 on the third side surface 23 of the housing 2. The pair of actuator ports 31 are connected to the corresponding hydraulic actuators 7 by piping.

[0021] The housing 2 is provided with a pair of actuator passages 8 for each spool hole 20, the pair extending from the spool hole 20 to an actuator port 31. In the neutral position, each spool 6 blocks the actuator passage 8 from the pump passage 11 and the tank passage 15. When the spool 6 moves, one side of the actuator passage 8 communicates with the pump passage 11 and the other side communicates with the tank passage 15.

[0022] The housing 2 is provided with a pair of relief passages 91, 92 that respectively connect the actuator passage 8 and the cross passage 16 of the tank passage 15. The relief passages 91, 92 are provided with relief valves 93, 94 each equipped with a check valve.

[0023] Container-shaped covers 41 are attached to the first side surface 21 of the housing 2, the number of which is the same as the number of spools 6. Each cover 41 forms a first pilot chamber 4A that faces one end face of the corresponding spool 6. With regard to the spool 6A, the outer end face of the first spool 61 faces the first pilot chamber 4A.

[0024] A spring 44 for maintaining the spool 6 in a neutral position is disposed within each cover 41. With respect to the spool 6A, the spring 44 maintains the first spool 61 in a neutral position. Note that the configuration around the spring 44 is well known, and therefore a detailed description thereof will be omitted.

[0025] Meanwhile, a block 42 extending in the arrangement direction of the spools 6 is attached to the second side surface 22 of the housing 2. The contact surface of the block 42 with the housing 2 is provided with recesses at positions corresponding to the spools 6 other than the spool 6A, and these recesses form a second pilot chamber 4B that faces the other end faces of the spools 6 other than the spool 6A.

[0026] A through hole 42a is provided in the block 42 at a position corresponding to the spool 6A, and this through hole 42a is closed by a cover 43. The cover 43 and the through hole 42a of the block 42 form a second pilot chamber 4B that faces the other end face of the spool 6A, i.e., the outer end face of the second spool 62.

[0027] A spring 45 is disposed within the through hole 42a to maintain the second spool 62 in a neutral position. Note that the configuration around the spring 45 is well known, so a detailed description thereof will be omitted.

[0028] A third pilot chamber 4C is formed between the inner end faces of the first spool 61 and the second spool 62 of the spool 6A.

[0029] The valve device 1 further includes first electromagnetic proportional valves 51, the number of which is the same as the number of spools 6, second electromagnetic proportional valves 52, the number of which is the same as the number of spools 6, and a third electromagnetic proportional valve 53 for the spool 6A. As shown in Fig. 3, the first electromagnetic proportional valves 51 are connected to the first pilot chamber 4A of the corresponding spool 6 through a pilot passage 2a, and the second electromagnetic proportional valves 52 are connected to the second pilot chamber 4B of the corresponding spool 6 through a pilot passage 2b. The third electromagnetic proportional valve 53 is connected to the third pilot chamber 4C of the spool 6A through a pilot passage 2c.

[0030] In this embodiment, a block 50 extending in the arrangement direction of the spools 6 is attached to the end of the fourth side surface 24 of the housing 2 on the first side surface 21 side. All of the first solenoid proportional valves 51, the second solenoid proportional valve 52 for the spool 6A, and the third solenoid proportional valve 53 are attached to the block 50. The second solenoid proportional valves 52 other than the second solenoid proportional valve 52 for the spool 6A are attached to the block 42.

[0031] The configuration of the cover 41 and the blocks 42, 50, and the mounting method of the first electromagnetic proportional valve 51, the second electromagnetic proportional valve 52, and the third electromagnetic proportional valve 53 can be changed as appropriate.

[0032] At least one of the blocks 50, 42 is provided with a primary pressure passage 17 and a drain passage 18, and a first solenoid proportional valve 51, a second solenoid proportional valve 52 and a third solenoid proportional valve 53 are connected to the primary pressure passage 17 and the drain passage 18.

[0033] Each first solenoid proportional valve 51 outputs secondary pressure to the first pilot chamber 4A of the corresponding spool 6, or communicates the first pilot chamber 4A with the drain passage 18. Each second solenoid proportional valve 52 outputs secondary pressure to the second pilot chamber 4B of the corresponding spool 6, or communicates the second pilot chamber 4B with the drain passage 18. The third solenoid proportional valve 53 outputs secondary pressure to the third pilot chamber 4C of the spool 6A, or communicates the third pilot chamber 4C with the drain passage 18.

[0034] That is, each of the spools 6 other than the spool 6A is driven by the first electromagnetic proportional valve 51 and the second electromagnetic proportional valve 52. The first spool 61 of the spool 6A is driven by the first electromagnetic proportional valve 51 and the third electromagnetic proportional valve 53, and the second spool 62 is driven by the second electromagnetic proportional valve 52 and the third electromagnetic proportional valve 53.

[0035] To explain the structure related to the spool 6A in more detail, the first actuator port 31a of the pair of actuator ports 31 is connected to a first working chamber 71 of the hydraulic cylinder 7A by piping, and the second actuator port 31b is connected to a second working chamber 72 of the hydraulic cylinder 7A by piping. In other words, one of the pair of actuator passages 8 is a first actuator passage 81 that extends from the spool hole 20 to the first actuator port 31a, and the other is a second actuator passage 82 that extends from the spool hole 20 to the second actuator port 31b.

[0036] The first spool 61 switches whether the first actuator passage 81 is connected to the pump passage 11 or the tank passage 15, and the second spool 62 switches whether the second actuator passage 82 is connected to the pump passage 11 or the tank passage 15.

[0037] In this embodiment, when the first spool 61 and the second spool 62 move away from each other, the pump passage 11 communicates with the first actuator passage 81, and the second actuator passage 82 communicates with the tank passage 15. Conversely, when the first spool 61 and the second spool 62 move toward each other, the pump passage 11 communicates with the second actuator passage 82, and the first actuator passage 81 communicates with the tank passage 15.

[0038] However, conversely to this embodiment, when the first spool 61 and the second spool 62 move toward each other, the first actuator passage 81 and the second actuator passage 82 may be connected to the pump passage 11 and the tank passage 15, respectively, and when the first spool 61 and the second spool 62 move away from each other, the second actuator passage 82 and the first actuator passage 81 may be connected to the pump passage 11 and the tank passage 15, respectively.

[0039] A lock valve 83 that opens and closes the first actuator passage 81 is provided in the first actuator passage 81 through which hydraulic oil flows toward the spool hole 20 when the driven object moves in the direction of gravity. The lock valve 83 closes the first actuator passage 81 when the hydraulic cylinder 7A is stopped.

[0040] Specifically, the lock valve 83 is a poppet valve having a back pressure chamber, and the back pressure chamber is connected to an on-off valve 85 by a first communication passage 84. The on-off valve 85 is connected to a portion of the first actuator passage 81 between the lock valve 83 and the first actuator port 31a by a second communication passage 86, and is connected to the drain passage 18 by a third communication passage 87.

[0041] The on-off valve 85 is located at a locked position where the first communication passage 84 communicates with the second communication passage 86 while the hydraulic cylinder 7A is stopped, and is switched to an unlocked position where the first communication passage 84 communicates with the third communication passage 87 when the hydraulic cylinder 7A is operated. In the illustrated example, the on-off valve 85 is a solenoid valve that is operated by an electric signal, but the on-off valve 85 may also be operated by a pilot pressure.

[0042] In this embodiment, only the hydraulic cylinder 7A is the target for detecting the supply pressure or discharge pressure, and the first sensor port 32 and the second sensor port 33 are formed on the first side surface 21 of the housing 2. However, one or both of the first sensor port 32 and the second sensor port 33 may be formed on the second side surface 22.

[0043] The housing 2 is provided with a first sensor passage 34 that connects the first actuator passage 81 and the first sensor port 32, and a second sensor passage 35 that connects the second actuator passage 82 and the second sensor port 33. The first sensor passage 34 is connected to the first actuator passage 81 between the spool hole 20 and the lock valve 83.

[0044] As described above, in the valve device 1 of this embodiment, the first sensor port 32 is located on the first side surface 21, which is a part of the surface of the housing 2, and the first sensor port 32 is connected to the first actuator passage 81 through the first sensor passage 34. Therefore, if a pressure gauge is attached to the first sensor port 32, the pressure gauge can detect the supply pressure when working oil is supplied to the hydraulic cylinder 7A through the first actuator passage 81, or the discharge pressure when working oil is discharged from the hydraulic cylinder 7A through the first actuator passage 81.

[0045] In addition, in this embodiment, since the lock valve 83 is provided in the first actuator passage 81, when the lock valve 83 closes the first actuator passage 81, the hydraulic oil is prevented from flowing from the first actuator port 31a to the spool hole 20. Therefore, even if a malfunction occurs in the first sensor port 32 or the pressure gauge attached to the first sensor port 32, the lock valve 83 closes the first actuator passage 81, thereby preventing the hydraulic oil from the first actuator port 31a from leaking out from the first sensor port 32. Moreover, since the first actuator passage 81 is connected to the first working chamber 71 which is pressurized by the weight of the driven object in the hydraulic cylinder 7A, it is possible to prevent the hydraulic oil from leaking out from the first sensor port 32 due to the weight of the driven object when the hydraulic cylinder 7A is stopped.

[0046] Furthermore, in this embodiment, there is a second sensor port 33 on the first side 21 of the housing 2, and the second sensor port 33 is connected to the second actuator passage 82 through the second sensor passage 35. Therefore, if a pressure gauge is attached to the second sensor port 33, the pressure gauge can detect the supply pressure when hydraulic oil is supplied to the hydraulic cylinder 7A through the second actuator passage 82, or the discharge pressure when hydraulic oil is discharged from the hydraulic cylinder 7A through the second actuator passage 82.

[0047] Furthermore, in this embodiment, the spool 6A for the hydraulic cylinder 7A is a split type divided into the first spool 61 and the second spool 62, so that independent metering control can be performed on the meter-in side and the meter-out side.

[0048] <Modification> The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0049] For example, the second sensor port 33 and the second sensor passage 35 may be omitted, and only the first sensor port 32 and the first sensor passage 34 may be used. Alternatively, conversely, the first sensor port 32 and the first sensor passage 34 may be omitted, and only the second sensor port 33 and the second sensor passage 35 may be used.

[0050] Furthermore, the hydraulic actuator 7 connected to the first actuator port 31a and the second actuator port 31b, i.e., the hydraulic actuator 7 for which the supply pressure or discharge pressure is to be detected, may be a hydraulic cylinder other than the hydraulic cylinder 7A that drives the driven object in the gravity direction and the antigravity direction. Alternatively, the hydraulic actuator 7 for which the supply pressure or discharge pressure is to be detected may be a hydraulic motor.

[0051] 4, the spool 6 for the hydraulic actuator 7 that is the subject of supply pressure or discharge pressure detection may be an integrated type that extends across two cross passages 16 of the tank passage 15. In other words, all hydraulic actuators 7 may be subjects of supply pressure or discharge pressure detection. In this case, the total number of sensor ports on the first side surface 21 and the second side surface 22 of the housing 2 is greater than or equal to one time and less than or equal to two times the total number of spools 6.

[0052] In addition, the first sensor port 32 does not necessarily have to be formed on the first side surface 21 or the second side surface 22, but may be formed on the fourth side surface 24, the first end surface 25, or the second end surface 26. Similarly, the second sensor port 33 does not necessarily have to be formed on the first side surface 21 or the second side surface 22, but may be formed on the fourth side surface 24, the first end surface 25, or the second end surface 26.

[0053] <Summary> In a first aspect, the present disclosure provides a valve device comprising a spool and a housing that slidably holds the spool, the housing including a spool hole into which the spool is inserted, a sensor port on a surface of the housing, a first actuator port and a second actuator port, a first actuator passage extending from the spool hole to the first actuator port, a second actuator passage extending from the spool hole to the second actuator port, and a sensor passage communicating between the first actuator passage and the sensor port.

[0054] According to the above configuration, a sensor port is provided on the surface of the housing and is connected to the first actuator passage through a sensor passage. Therefore, by attaching a pressure gauge to the sensor port, the pressure gauge can detect the supply pressure when working oil is supplied to the hydraulic actuator through the first actuator passage, or the discharge pressure when working oil is discharged from the hydraulic actuator through the first actuator passage.

[0055] As a second aspect, in the first aspect, for example, the housing may include a first side and a second side facing opposite each other along the axial direction of the spool, and a third side and a fourth side facing opposite each other along a direction perpendicular to the axial direction of the spool, the sensor port being formed on the first side or the second side, and the first actuator port and the second actuator port being formed on the third side.

[0056] As a third aspect, in the first or second aspect, the first actuator passage may be provided with a lock valve that opens and closes the first actuator passage, and the sensor passage may be connected to the first actuator passage between the spool hole and the lock valve. With this configuration, when the lock valve closes the first actuator passage, hydraulic oil is prevented from flowing from the first actuator port to the spool hole. Therefore, even if a malfunction occurs in the sensor port or a pressure gauge attached to the sensor port, the lock valve closes the first actuator passage, thereby preventing hydraulic oil from the first actuator port from leaking out of the sensor port.

[0057] As a fourth aspect, in the third aspect, the valve device may be used in a hydraulic cylinder including a first working chamber to which hydraulic oil is supplied when an object to be driven is driven in an antigravity direction, and a second working chamber to which hydraulic oil is supplied when the object to be driven is driven in a gravity direction, the first actuator port is connected to the first working chamber, the second actuator port is connected to the second working chamber, and the lock valve closes the first actuator passage when the hydraulic cylinder is stopped. With this configuration, it is possible to prevent leakage of hydraulic oil from a sensor port due to the weight of the object to be driven when the hydraulic cylinder is stopped.

[0058] As a fifth aspect, in any of the first to fourth aspects, the sensor port may be a first sensor port, the sensor passage may be a first sensor passage, and the housing may include a second sensor port on a surface of the housing and a second sensor passage communicating between the second actuator passage and the second sensor port. According to this configuration, by attaching a pressure gauge to the second sensor port, it is possible to detect, by the pressure gauge, a supply pressure when hydraulic oil is supplied to the hydraulic actuator through the second actuator passage or a discharge pressure when hydraulic oil is discharged from the hydraulic actuator through the second actuator passage.

[0059] As a sixth aspect, in any one of the first to fifth aspects, the spool may include a first spool that switches whether the first actuator passage is communicated with a pump passage or a tank passage, and a second spool that switches whether the second actuator passage is communicated with the pump passage or the tank passage. With this configuration, independent metering control can be performed on the meter-in side and the meter-out side. [Explanation of symbols]

[0060] 1 Valve gear 11 Pump passage 15 Tank Passage 2. Housing 20 spool holes 21 First aspect 22 Second aspect 23 Third aspect 24 Fourth aspect 31 Actuator Port 31a No. 1 actuator port 31b Second Actuator Port 32 1st Sensor Port 33 Second Sensor Port 34 First sensor passage 35 Second Sensor Passage 6,6A spool 61 First spool 62 Second spool 7 Hydraulic Actuators 7A Hydraulic Cylinder 71 First working chamber 72 Second working chamber 81 First Actuator Passage 82 Second Actuator Passage 83 Lock valve

Claims

1. A spool and a housing that slidably holds the spool, The housing includes: a spool hole into which the spool is inserted; a sensor port, a first actuator port and a second actuator port on a surface of the housing; a first actuator passageway leading from the spool bore to the first actuator port; a second actuator passageway leading from the spool bore to the second actuator port; a sensor passage communicating the first actuator passage with the sensor port.

2. The housing includes: a first side surface and a second side surface facing in opposite directions along an axial direction of the spool; a third side surface and a fourth side surface facing opposite each other along a direction perpendicular to the axial direction of the spool; the sensor port is formed on the first side or the second side, The valve arrangement of claim 1 , wherein the first actuator port and the second actuator port are formed on the third side.

3. a lock valve for opening and closing the first actuator passage is provided in the first actuator passage, 3. The valve arrangement according to claim 1, wherein the sensor passage is connected to the first actuator passage between the spool bore and the lock valve.

4. The valve device is used in a hydraulic cylinder including a first working chamber to which hydraulic oil is supplied when an object to be driven is driven in an antigravity direction, and a second working chamber to which hydraulic oil is supplied when the object to be driven is driven in a gravity direction, the first actuator port is connected to the first working chamber, and the second actuator port is connected to the second working chamber; The valve arrangement of claim 3 , wherein the lock valve closes the first actuator passage when the hydraulic cylinder is deactivated.

5. the sensor port is a first sensor port, the sensor passage is a first sensor passage, The housing includes: a second sensor port on a surface of the housing; and 3. The valve apparatus according to claim 1, further comprising: a second sensor passage communicating between the second actuator passage and the second sensor port.

6. 3. The valve device according to claim 1, wherein the spool includes a first spool that switches whether the first actuator passage is communicated with a pump passage or a tank passage, and a second spool that switches whether the second actuator passage is communicated with the pump passage or the tank passage.

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