Fluid control valve, fluid system, construction machinery, and control method

Abstract

The present invention provides a fluid control valve, a fluid system, a construction machine, and a control method. The fluid control valve of the present invention comprises: a first valve spool that switches between connection and disconnection between a first actuator port, a second actuator port, a pump, and a tank; and a second valve spool that connects the first actuator port to the tank in response to switching by the first valve spool.

Description

Technical Field

[0001] The present invention relates to a fluid control valve, a fluid system, a construction machine and a control method. Background Art

[0002] Conventionally, a hydraulic excavator is known as a type of construction machinery. A hydraulic excavator includes attachments such as a boom, an arm, and a bucket that are actuated by hydraulic cylinders. The hydraulic excavator includes a fluid system for driving the attachments. The fluid system includes a fluid control valve that controls the supply and discharge of hydraulic oil relative to the hydraulic cylinder. Examples of such fluid control valves include a valve body having multiple passages and a check valve that prevents backflow of hydraulic oil supplied to the valve body (see, for example, Patent Document 1).

[0003] However, hydraulic excavators are not only used for excavation with a bucket but are also used for a variety of purposes by being equipped with attachments such as hydraulic breakers and crushers. Depending on the type of attachment, it is necessary to switch between single-action operation, where hydraulic oil is supplied from a pump, as in the case of a hydraulic breaker, or reciprocating operation, where hydraulic oil is supplied and discharged, as in the case of a crusher.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-141858 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, switching of the operation determined by the type of attachment requires manual switching of a switching valve provided in the passage.

[0009] On the other hand, although the switching of the above-mentioned actions can sometimes be operated from the cab, it still requires the installation of a complex circuit.

[0010] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a fluid control valve, a fluid system, a construction machine, and a control method that can switch the operation determined by the type of attachment with simple control.

[0011] Solutions for solving problems

[0012] As a solution to the above-mentioned problem, the present invention has the following configuration.

[0013] (1) A fluid control valve according to an embodiment of the present invention comprises: a first valve column that switches connection and blocking between a first actuator port, a second actuator port, a pump, and a tank; and a second valve column that connects the first actuator port to the tank in accordance with the switching performed by the first valve column.

[0014] According to this configuration, by using a plurality of spools, namely the first spool and the second spool, it is possible to perform switching between connection and blockage of the first actuator port, the second actuator port, the pump, and the tank with simple control.

[0015] (2) In the fluid control valve described in (1) above, the first valve column may be switched between a first position in which the first actuator port is connected to the pump and the second actuator port is connected to the tank, and a second position in which the second actuator port is connected to the pump, and the second valve column connects the first actuator port to the tank when the first valve column is in the second position.

[0016] According to this structure, when the first valve spool is in the second position, the second valve spool connects the first actuator port to the tank, thereby simplifying the control. Therefore, the operation determined by the type of attachment can be switched with simple control.

[0017] (3) In the fluid control valve described in (2) above, the first spool may not be fixed to the second spool.

[0018] (4) In the fluid control valve described in any one of (1) to (3) above, the second spool may block the first actuator port from the tank when the first spool is located at the first position.

[0019] (5) In any one of the above-mentioned (1) to (4), the fluid control valve may include: two first control valves that drive the first valve spool; and one second control valve that drives the second valve spool.

[0020] (6) In the fluid control valve described in any one of (1) to (5) above, the fluid control valve may also include a pump switching valve, wherein the pump is composed of a first pump and a second pump, and the pump switching valve switches the connection and blocking of at least one of the first pump passage between the first pump and the first valve column and the second pump passage between the second pump and the first valve column.

[0021] (7) The fluid control valve of the present invention comprises: a first valve column, which can obtain a first position in which the first actuator port is connected to the pump and the second actuator port is connected to the tank, or a second position in which the second actuator port is connected to the pump; a second valve column, which connects the first actuator port to the tank when the first valve column is in the second position and blocks the first actuator port from the tank when the first valve column is in the first position, and the second valve column is not fixed to the first valve column; two first control valves, which drive the first valve column; one second control valve, which drives the second valve column; and a pump switching valve, wherein the pump is composed of a first pump and a second pump, and the pump switching valve switches the connection and blocking of at least one of the first pump passage between the first pump and the first valve column and the second pump passage between the second pump and the first valve column.

[0022] According to this structure, when the first valve column is in the second position, the second valve column connects the first actuator port to the tank, so that the control can be simplified. Therefore, the switching of the action determined by the type of accessory can be performed with simple control. In addition, three control valves are used to control the two valve columns, so compared with the case of using four control valves to control four valve columns, the switching of the action determined by the type of accessory can be performed with a simple structure. In addition, it is possible to switch to the fluid being supplied by only one pump passage or the fluid being supplied by two pump passages. For example, in a construction machine (such as a hydraulic excavator) composed of two pump systems according to the capacity of the accessory, it is possible to switch to the flow rate of only one pump or the flow rate after the two pumps are merged.

[0023] (8) The fluid control valve of the present invention comprises: a first valve column, which allows the fluid to flow from the pump to the first actuator port and the fluid to flow from the second actuator port to the tank when the valve column is located in the first position, and allows the fluid to flow from the pump to the second actuator port when the valve column is located in the second position; and a second valve column, which allows the fluid to flow from the first actuator port to the tank when the first valve column is located in the second position.

[0024] According to this structure, when the first spool is in the second position, the second spool causes the fluid to flow from the first actuator port to the tank, thereby simplifying the control. Therefore, the operation determined by the type of accessory can be switched with simple control.

[0025] (9) A fluid system according to an aspect of the present invention includes: the fluid control valve according to any one of (1) to (8) above; a pump; and a driver driven by the fluid of the pump.

[0026] (10) The construction machine according to the embodiment of the present invention includes the fluid system described in (9) above.

[0027] (11) A control method according to a form of the present invention, wherein, in the control method, when the first valve column that can obtain the first position in which the first actuator port is connected to the pump and the second actuator port is connected to the tank, or the second position in which the second actuator port is connected to the pump, is located at the second position, the first actuator port is connected to the tank by using the second valve column.

[0028] According to this method, when the first valve spool is in the second position, the second valve spool connects the first actuator port to the tank, thereby simplifying control. Therefore, the operation determined by the type of attachment can be switched with simple control.

[0029] Effects of the Invention

[0030] According to the present invention, it is possible to provide a fluid control valve, a fluid system, a construction machine, and a control method capable of switching an operation determined by the type of attachment by simple control. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a construction machine according to an embodiment.

[0032] Figure 2 It is a schematic structural diagram of a fluid system according to an embodiment.

[0033] Figure 3 is a cross-sectional view of a fluid system according to an embodiment.

[0034] Figure 4 It is an explanatory diagram of an example of the operation of the fluid control valve according to the embodiment.

[0035] Figure 5 It is an explanatory diagram of another example of the operation of the fluid control valve according to the embodiment.

[0036] Figure 6 It is an explanatory diagram of switching control of the fluid control valve according to the embodiment.

[0037] Description of Reference Numerals

[0038] 1. Construction machinery; 10. Fluid system; 11. Fluid control valve; 12. Hydraulic pump (pump); 13. Hydraulic cylinder, hydraulic actuator (driving body); 13a, 1st actuator port; 13b, 2nd actuator port; 14. Tank; 40A, 1st valve column; 40B, 2nd valve column; 51, 1st solenoid proportional valve (1st control valve); 52, 2nd solenoid proportional valve (1st control valve); 53, 3rd solenoid proportional valve (2nd control valve); 54, 4th solenoid proportional valve (pump switching valve); 65, 1st pump passage; 66, 2nd pump passage. DETAILED DESCRIPTION

[0039] The following describes embodiments of the present invention with reference to the accompanying drawings. In the following embodiments, a hydraulic excavator equipped with a fluid system is used as an example of a construction machine. In the drawings used in the following description, the scale of each component has been appropriately altered to ensure that the components are of a recognizable size.

[0040] [Construction machinery]

[0041] Figure 1 It is a schematic diagram of the construction machine 1 according to the first embodiment.

[0042] For example, the construction machine 1 is a hydraulic excavator. The construction machine 1 includes a revolving body 2 and a traveling body 3. The revolving body 2 is rotatably provided on the traveling body 3. The revolving body 2 includes a hydraulic pump 12 (pump) for supplying hydraulic oil (fluid).

[0043] The revolving structure 2 includes a cab 5 in which an operator can sit; a boom 6, one end of which is swingably connected to the cab 5; an arm 7, one end of which is swingably connected to the other end (top end) of the boom 6 on the opposite side from the cab 5; and a bucket 8, which is swingably connected to the other end (top end) of the arm 7 on the opposite side from the boom 6. A hydraulic pump 12 is located within the cab 5. The cab 5, boom 6, arm 7, and bucket 8 are driven by hydraulic oil supplied from the hydraulic pump 12.

[0044] [Fluid System]

[0045] Figure 2 : is a schematic diagram of the fluid system 10 of the embodiment. Figure 2 The hydraulic pump 12 and the like are omitted from the figure. Figure 3 : is a cross-sectional view of the fluid system 10 according to the embodiment. Figure 3 The pump switching valve 54 and the like are omitted from the figure.

[0046] like Figure 3 As shown in FIG, the fluid system 10 includes a fluid control valve 11, a hydraulic pump 12, and a hydraulic actuator 13 (driving body) driven by hydraulic oil. For example, the hydraulic actuator 13 is a hydraulic motor, a hydraulic cylinder, etc. Figure 3 1 and 2 show a hydraulic cylinder as the hydraulic actuator 13. In the figure, reference numeral 14 denotes a tank for storing hydraulic oil.

[0047] [Fluid Control Valve]

[0048] The fluid control valve 11 controls the supply and discharge of hydraulic oil to and from the hydraulic cylinder 13. The fluid control valve 11 includes: a plurality of (for example, two in this embodiment) check valves 20; a valve body 30 having a plurality of passages 31 to 37; a first spool 40A; a second spool 40B; first control valves 51 and 52; a second control valve 53; and a pump switching valve 54 (see FIG. Figure 2 ). The fluid control valve 11 is a slide valve type reversing valve.

[0049] The plurality of passages 31 to 37 are flow passages (oil passages) through which hydraulic oil flows and include the spool hole 31 , the first actuator passage 32 , the second actuator passage 33 , the bypass passage 34 , the bridge passage 35 , the first supply passage 36 , and the second supply passage 37 .

[0050] The spool hole 31 is a hole into which the spools 40A and 40B can be inserted. The spool hole 31 is substantially perpendicular to the axis C1 of the check valve 20 ( Figure 3 The valve body 30 extends in the left-right direction (in the direction of the opening of the spool hole 31) through the valve body 30. The spools 40A and 40B are detachably inserted into the spool hole 31. The spools 40A and 40B extend in the direction of the opening of the spool hole 31. The spools 40A and 40B have shoulders 41 that can contact the inner circumferential surface of the spool hole 31. The spools 40A and 40B open and close the flow path and perform throttling operations by moving in the direction of the opening of the spool hole 31. The position of the spools 40A and 40B controls the flow rate of the hydraulic oil supplied to the hydraulic cylinder 13.

[0051] The first actuator passage 32 is arranged on one side of the check valve 20. The first actuator passage 32 is parallel to the axis C1 ( Figure 3 The first actuator passage 32 extends in the vertical direction and in the direction perpendicular to the opening direction of the valve stem hole 31. Figure 3 The upper end of the second actuator passage 33 is connected to the first actuator port 13a (for example, the rod side oil chamber) of the hydraulic cylinder 13. The other end of the second actuator passage 33 ( Figure 3 The lower end of the valve stem is connected to the valve stem hole 31.

[0052] The second actuator passage 33 is arranged on the other side of the check valve 20. That is, the second actuator passage 33 is arranged on the opposite side of the first actuator passage 32 across the check valve 20. The second actuator passage 33 is parallel to the first actuator passage 32 ( Figure 3 One end of the second actuator passage 33 ( Figure 3 The upper end of the second actuator passage 33 is connected to the second actuator port 13b of the hydraulic cylinder 13 (for example, the cylinder head side oil chamber). The other end of the second actuator passage 33 ( Figure 3 The lower end of the valve stem is connected to the valve stem hole 31.

[0053] The bypass passage 34 branches off from the spool hole 31. The bypass passage 34 includes a first bypass path 34a, a second bypass path 34b, and a third bypass path 34c.

[0054] The first bypass path 34a is located on the side of the first actuator passage 32 and is substantially parallel to the first actuator passage 32 ( Figure 3 That is, the first bypass path 34a is located on the side of the first actuator passage 32 and extends in a direction parallel to the first actuator passage 32 ( Figure 3 Extending in the up and down directions).

[0055] The second bypass path 34b is located on the side of the second actuator passage 33 and is substantially parallel to the first bypass path 34a. Figure 3 That is, the second bypass path 34b is located on the side of the second actuator passage 33 and extends in a direction parallel to the first bypass path 34a ( Figure 3 Extending in the up and down directions).

[0056] The third bypass path 34c extends in a direction substantially parallel to the opening direction of the spool hole 31 and is connected to one end ( Figure 3 The lower end of the second bypass path 34b and one end of the second bypass path 34b Figure 3 That is, the third bypass path 34c extends in a direction parallel to the opening direction of the spool hole 31 and connects one end of the first bypass path 34a ( Figure 3 The lower end of the second bypass path 34b and one end of the second bypass path 34b Figure 3 The third bypass path 34c is arranged on the side opposite to the check valve 20 across the spool hole 31.

[0057] The bridge passage 35 has an inverted U-shape in cross-section. Both ends of the bridge passage 35 are connected to the spool hole 31 .

[0058] The first supply passage 36 and the second supply passage 37 are arranged near the spool hole 31. The first supply passage 36 and the second supply passage 37 are arranged in the opening direction of the spool hole 31 ( Figure 3 The first supply passage 36 and the second supply passage 37 are connected to the middle of the bridge passage 35.

[0059] In the opening direction of the valve column hole 31 ( Figure 3 A pair of check valves 20 are arranged in a row in the left-right direction. The pair of check valves 20 are arranged at adjacent positions across the wall portion 30a of the valve body 30. Figure 3 , reference numeral 18 denotes a plug covering an end portion of a check valve 20 .

[0060] The first spool 40A switches between connection and disconnection between two different actuator ports 13a and 13b (first actuator port 13a and second actuator port 13b), the hydraulic pump 12, and the tank 14. The first spool 40A can switch between multiple connection states of the passages 31 to 37. The multiple connection states include a first position and a second position (see FIG. Figure 4 、 Figure 5 The first position is a position where the first actuator port 13a is connected to the hydraulic pump 12 and the second actuator port 13b is connected to the tank 14 (see Figure 5 The second position is a position where the second actuator port 13b is connected to the hydraulic pump 12 (see Figure 4 ). The first spool 40A is not fixed to the second spool 40B.

[0061] When the first spool 40A is in the first position, hydraulic oil flows from the hydraulic pump 12 to the first actuator port 13a and flows from the second actuator port 13b to the tank 14. When the first spool 40A is in the second position, hydraulic oil flows from the hydraulic pump 12 to the second actuator port 13b.

[0062] The second valve spool 40B is provided independently of the first valve spool 40A. The second valve spool 40B is shorter than the first valve spool 40A in the direction of the opening of the valve spool hole 31. The second valve spool 40B switches between connection and blocking between the first actuator port 13a and the tank 14. The second valve spool 40B connects the first actuator port 13a and the tank 14 in accordance with the switching performed by the first valve spool 40A. The second valve spool 40B connects the first actuator port 13a and the tank 14 when the first valve spool 40A is in the second position (see Figure 4 ). The second spool 40B blocks the first actuator port 13a from the tank 14 when the first spool 40A is located at the first position (see Figure 5 When the first spool 40A is located at the first position (when the first actuator port 13 a and the hydraulic pump 12 are connected), the second spool 40B does not operate (is in a stopped state).

[0063] The second spool 40B allows the hydraulic oil to flow from the first actuator port 13a to the tank 14 when the first spool 40A is in the second position. The second spool 40B does not allow the hydraulic oil to flow from the first actuator port 13a to the tank 14 when the first spool 40A is in the first position.

[0064] exist Figure 3 In FIG. 4 , reference numeral 42A denotes a first coil spring for holding the first spool 40A at a predetermined position (for example, a return spring for returning the first spool 40A to a neutral position). Figure 3In FIG. 4 , reference numeral 43 denotes a pilot port provided on one end side of the first spool 40A. Figure 3 In FIG, reference numeral 42B indicates a second coil spring for holding the second spool 40B at a predetermined position (for example, a return spring for returning the second spool 40B to an initial position). Figure 3 In FIG. 1 , reference numerals 44 denote pilot ports provided on one end side of the second spool 40B.

[0065] The first control valves 51 and 52 switch the first spool 40A to either the first position or the second position, and control the hydraulic actuator driven by the hydraulic oil. Two first control valves 51 and 52 are provided. The two first control valves 51 and 52 are used to move the first spool 40A in one direction ( Figure 3 The control valve 51 (hereinafter also referred to as the "first electromagnetic proportional valve 51") is used to move the first spool 40A in the other direction (the right direction) of the opening direction of the spool hole 31. Figure 3 The control valve 52 (hereinafter also referred to as the "second electromagnetic proportional valve 52") moves in the left direction).

[0066] The second control valve 53 controls the second spool 40B so that the second spool 40B does not operate when the first control valves 51 and 52 switch the first spool 40A to the first position. Only one second control valve 53 is provided.

[0067] In the figure, reference numeral 61 denotes the first tank passage between the first actuator port 13a and the tank 14, and reference numeral 62 denotes the second tank passage between the second actuator port 13b and the tank 14. The first tank passage 61 is a passage including the first actuator passage 32 and the first bypass path 34a. The second tank passage 62 is a passage including the second actuator passage 33 and the second bypass path 34b. The second control valve 53 is provided midway in the first tank passage 61, independently of the first control valves 51 and 52. The second control valve 53 is connected to a portion of the spool hole 31 that leads to the first tank passage 61. Hereinafter, the second control valve 53 will also be referred to as the "third solenoid proportional valve 53."

[0068] like Figure 2 As shown, only one pump switching valve 54 is provided. In the figure, reference numeral 65 indicates a component of the hydraulic pump 12 (see Figure 3 ) and the first valve spool 40A. Reference numeral 66 denotes a second pump passage between the second pump constituting the hydraulic pump 12 and the first valve spool 40A. A pump switching valve 54 is provided midway along the second pump passage 66. The pump switching valve 54 connects or blocks the second pump passage 66. Hereinafter, the pump switching valve 54 will also be referred to as the "fourth solenoid proportional valve 54."

[0069] [Operation of Fluid Control Valve]

[0070] Figure 4 It is an explanatory diagram of an example of the operation of the fluid control valve 11 according to the embodiment. Figure 5 It is an explanatory diagram of another example of the operation of the fluid control valve 11 according to the embodiment. Figure 6 It is an explanatory diagram of switching control of the fluid control valve 11 according to the embodiment.

[0071] like Figure 6 As shown, in this embodiment, four electromagnetic proportional valves can be used to switch between single action, reciprocating action, and one pump or two pumps.

[0072] Figure 4 This shows a case where the first electromagnetic proportional valve 51 is turned on, the second electromagnetic proportional valve 52 is turned off, and the third electromagnetic proportional valve 53 is turned on.

[0073] like Figure 4 As shown in FIG. 1 , if the first electromagnetic proportional valve 51 is turned on and the second electromagnetic proportional valve 52 is turned off, the first spool 40A is moved to Figure 4 At this time, if the first valve column 40A is pushed in the opening direction of the valve column hole 31 by the first coil spring 42A (refer to Figure 3 ) is pushed strongly by the elastic force, the first valve stem 40A overcomes the first coil spring 42A and moves to Figure 4 That is, the first valve column 40A is shifted to the right side relative to the neutral position. Figure 4 As a result, the second actuator port 13b is connected to the hydraulic pump 12, the first actuator port 13a is blocked from the hydraulic pump 12, and the second actuator port 13b is blocked from the tank 14 (second position).

[0074] When the third electromagnetic proportional valve 53 is turned on, the second spool 40B is moved to Figure 4 At this time, if the second valve column 40B is pushed in the opening direction of the valve column hole 31 by the second coil spring 42B (refer to Figure 3 ) is pushed strongly by the elastic force, the second valve rod 40B overcomes the second coil spring 42B and moves to Figure 4 Thus, the first actuator port 13a is connected to the tank 14. That is, the hydraulic oil can flow through the first tank passage 61, but the hydraulic oil cannot flow through the second tank passage 62.

[0075] Figure 5 This shows a case where the first electromagnetic proportional valve 51 is turned off, the second electromagnetic proportional valve 52 is turned on, and the third electromagnetic proportional valve 53 is turned off.

[0076] like Figure 5As shown in FIG. 1 , if the first electromagnetic proportional valve 51 is turned off and the second electromagnetic proportional valve 52 is turned on, the first spool 40A is moved to Figure 5 The left side (with Figure 4 At this time, if the first valve column 40A is pushed in the opening direction of the valve column hole 31 by the first coil spring 42A (refer to Figure 3 ) is pushed strongly by the elastic force, the first valve stem 40A overcomes the first coil spring 42A and moves to Figure 5 That is, the first valve column 40A is shifted to the left side relative to the neutral position. Figure 5 As a result, the first actuator port 13a is connected to the hydraulic pump 12, while the second actuator port 13b is connected to the tank 14, and the second actuator port 13b is blocked from the hydraulic pump 12 (first position).

[0077] When the third solenoid proportional valve 53 is turned off, the second spool 40B is not pressed and stops at its initial position. This blocks the connection between the first actuator port 13a and the tank 14. In other words, hydraulic oil cannot flow through the first tank passage 61, but can flow through the second tank passage 62.

[0078] At the first position, the hydraulic pump 12 supplies hydraulic oil to the first actuator port 13a, so that the rod of the hydraulic cylinder 13 can move to the first position. Figure 5 Left shift (refer to Figure 5 At the second position, the hydraulic pump 12 supplies hydraulic oil to the second actuator port 13b, so that the rod of the hydraulic cylinder 13 can move to the Figure 4 The right side shift (refer to Figure 4 Thus, in this embodiment, the three electromagnetic proportional valves 51 to 53 (the first electromagnetic proportional valve 51 , the second electromagnetic proportional valve 52 , and the third electromagnetic proportional valve 53 ) can be used to switch between single action and reciprocating action.

[0079] like Figure 2 As shown in FIG, if the fourth electromagnetic proportional valve 54 is turned on, the second pump passage 66 is blocked. That is, only the first pump passage 65 is connected. Thus, the working oil can be supplied from only one pump passage 65 (only the flow rate of one pump) (refer to FIG. Figure 6 ).

[0080] On the other hand, if the fourth electromagnetic proportional valve 54 is turned off, the second pump passage 66 is connected. That is, the first pump passage 65 and the second pump passage 66 are connected. As a result, the hydraulic oil can be supplied from the two pump passages 65 and 66 (the flow rate after the two pumps merge) (see Figure 6 ).

[0081] As described above, in the present embodiment, the fourth electromagnetic proportional valve 54 can be used to switch between one pump and two pumps.

[0082] As described above, the fluid control valve 11 of this embodiment includes a first valve column 40A, a second valve column 40B, two first control valves 51 and 52 for driving the first valve column 40A, a second control valve 53 for driving the second valve column 40B, a hydraulic pump 12 composed of a first pump and a second pump, and a pump switching valve 54.

[0083] The first spool 40A can take a first position connecting the first actuator port 13 a to the hydraulic pump 12 and connecting the second actuator port 13 b to the tank 14 , or a second position connecting the second actuator port 13 b to the hydraulic pump 12 .

[0084] The second spool 40B connects the first actuator port 13a and the tank 14 when the first spool 40A is in the second position, and blocks the first actuator port 13a and the tank 14 when the first spool 40A is in the first position.

[0085] The pump switching valve 54 switches between connection and blocking of a first pump passage 65 between the first pump and the first spool 40A and a second pump passage 66 between the second pump and the first spool 40A.

[0086] According to this embodiment, when the first spool 40A is in the second position, the second spool 40B connects the first actuator port 13a and the tank 14, thereby simplifying control. Therefore, the operation can be switched depending on the type of attachment with simple control.

[0087] Furthermore, since the two spools 40A and 40B are controlled by the three control valves 51 to 53 , the operation determined by the type of attachment can be switched with a simple configuration compared to a case where four spools are controlled by four control valves.

[0088] Furthermore, it is possible to switch between supplying hydraulic oil through only one pump passage 65 or supplying hydraulic oil through both pump passages 65 and 66. For example, in a construction machine 1 (e.g., a hydraulic excavator) that includes two pump systems depending on the capacity of the attachment, it is possible to switch between a flow rate from only one pump and a flow rate obtained by combining the two pumps.

[0089] The fluid system 10 of the present embodiment includes the above-mentioned fluid control valve 11 , a hydraulic pump 12 , and a driving body 13 driven by the hydraulic fluid of the hydraulic pump 12 .

[0090] According to this configuration, it is possible to provide the fluid system 10 that can switch the operation determined by the type of attachment by simple control.

[0091] The construction machine 1 of this embodiment includes the above-mentioned fluid system 10 .

[0092] According to this configuration, it is possible to provide the construction machine 1 that can switch the operation depending on the type of attachment by simple control.

[0093] The protective scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0094] In the above embodiment, the construction machine 1 is described as an example of a hydraulic excavator, but the present invention is not limited to this. For example, the present invention can also be applied to construction machines other than hydraulic excavators.

[0095] In the above-mentioned embodiment, the following fluid control valve is listed and described, which includes: a first valve column 40A, which can obtain a first position in which the first actuator port 13a is connected to the hydraulic pump 12 and the second actuator port 13b is connected to the tank 14, or a second position in which the second actuator port 13b is connected to the hydraulic pump 12; and a second valve column 40B, which connects the first actuator port 13a and the tank 14 when the first valve column 40A is in the second position, but the present invention is not limited to this. For example, the present invention can also be applied to the following control method, in which the first actuator port 13a and the tank 14 are connected using the second valve spool 40B when the first valve spool 40A is in the second position, which can achieve the first position in which the first actuator port 13a is connected to the hydraulic pump 12 and the second actuator port 13b is connected to the tank 14, or the second position in which the second actuator port 13b is connected to the hydraulic pump 12.

[0096] In the above embodiment, an example is described in which two first control valves 51 and 52 are provided, and only one second control valve 53 is provided. However, the present invention is not limited to this. For example, only one first control valve may be provided, and two second control valves may be provided. The number of first and second control valves provided can be changed according to the required specifications.

[0097] In the above embodiment, the fluid control valve 11 is described as including the pump switching valve 54, but the present invention is not limited to this. For example, the fluid control valve 11 may not include the pump switching valve 54. In other words, it is sufficient as long as the three solenoid proportional valves 51 to 53 (the first solenoid proportional valve 51, the second solenoid proportional valve 52, and the third solenoid proportional valve 53) can switch between single-acting and reciprocating motions.

[0098] In the above embodiment, the fluid system (hydraulic system) is described as an example in which a hydraulic actuator is driven by the working oil of a hydraulic pump, but the invention is not limited to this. For example, the present invention can also be applied to a fluid system having a driving body driven by a fluid other than working oil (fluid of a pump).

[0099] Furthermore, the components in the above-described embodiment can be replaced with well-known components without departing from the scope of the present invention. In addition, there is no problem even if the above-described modifications are combined.

Claims

1. A fluid control valve, wherein: The fluid control valve has: a first valve spool that switches connection and blocking between the first actuator port, the second actuator port, the pump, and the tank; a second spool that connects the first actuator port to the tank in response to switching by the first spool; two first control valves driving the first valve spools; and a second control valve that drives the second valve spool, The first valve stem and the second valve stem are inserted into the valve stem holes penetrating the valve body. The first valve post and the second valve post extend in the opening direction of the valve post hole. The second spool is shorter than the first spool in the opening direction of the spool hole.

2. The fluid control valve according to claim 1, wherein: The first spool switches between a first position in which the first actuator port is connected to the pump and the second actuator port is connected to the tank, and a second position in which the second actuator port is connected to the pump. The second spool connects the first actuator port and the tank when the first spool is located at the second position.

3. The fluid control valve according to claim 2, wherein: The first valve spool is not fixed to the second valve spool.

4. The fluid control valve according to claim 2, wherein: The second spool blocks communication between the first actuator port and the tank when the first spool is located at the first position.

5. The fluid control valve according to claim 3, wherein: The second spool blocks communication between the first actuator port and the tank when the first spool is located at the first position.

6. The fluid control valve according to any one of claims 1 to 5, wherein: The fluid control valve includes a pump switching valve, wherein the pump is composed of a first pump and a second pump, and the pump switching valve switches between connection and blocking of at least one of a first pump passage between the first pump and the first valve column and a second pump passage between the second pump and the first valve column.

7. A fluid control valve, wherein: The fluid control valve has: a first valve spool capable of taking a first position connecting the first actuator port to the pump and connecting the second actuator port to the tank, or a second position connecting the second actuator port to the pump; a second valve spool that connects the first actuator port to the tank when the first valve spool is in the second position and blocks the first actuator port from the tank when the first valve spool is in the first position, the second valve spool not being fixed to the first valve spool; two first control valves driving the first valve spools; a second control valve that drives the second spool; and a pump switching valve, wherein the pump is composed of a first pump and a second pump, and the pump switching valve switches between connection and blocking of at least one of a first pump passage between the first pump and the first valve spool and a second pump passage between the second pump and the first valve spool; The first valve stem and the second valve stem are inserted into the valve stem holes penetrating the valve body. The first valve post and the second valve post extend in the opening direction of the valve post hole. The second spool is shorter than the first spool in the opening direction of the spool hole.

8. A fluid control valve, wherein: The fluid control valve has: a first spool that allows fluid to flow from the pump to the first actuator port and from the second actuator port to the tank when in a first position, and allows fluid to flow from the pump to the second actuator port when in a second position; a second valve spool configured to allow fluid to flow from the first actuator port to the tank when the first valve spool is in the second position; two first control valves driving the first valve spools; and a second control valve that drives the second valve spool, The first valve stem and the second valve stem are inserted into the valve stem holes penetrating the valve body. The first valve post and the second valve post extend in the opening direction of the valve post hole. The second spool is shorter than the first spool in the opening direction of the spool hole.

9. A fluid system, wherein: The fluid system has: The fluid control valve according to any one of claims 1 to 8; pumps; and A driving body is driven by the fluid of the pump.

10. A construction machine, wherein: This construction machine includes the fluid system according to claim 9.

11. A control method, wherein: In this control method, when the first valve spool capable of taking a first position in which the first actuator port is connected to the pump and the second actuator port is connected to the tank, or a second position in which the second actuator port is connected to the pump, is in the second position, the first actuator port is connected to the tank by the second valve spool. The two first control valves drive the first valve column. A second control valve drives the second valve column, The first valve stem and the second valve stem are inserted into the valve stem holes penetrating the valve body. The first valve post and the second valve post extend in the opening direction of the valve post hole. The second spool is shorter than the first spool in the opening direction of the spool hole.

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