Fluid control valves, fluid systems, and construction machinery

Abstract

The present invention provides a fluid control valve, a fluid system, and a construction machine. The fluid control valve of the present invention comprises: a first check valve that allows fluid to flow from a first pump passage to a bridge supply passage; a second check valve that allows fluid to flow from a second pump passage to the bridge supply passage; and a third check valve that allows fluid to flow from a third pump passage to the bridge supply passage.

Description

Technical Field

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

[0002] In the past, a hydraulic excavator was known as a type of construction machinery. The hydraulic excavator has accessories such as a boom, an arm, and a bucket that are actuated by a hydraulic cylinder. The hydraulic excavator has a hydraulic system that drives the accessories. The hydraulic system has a hydraulic control valve that controls the supply and discharge of working oil relative to the hydraulic cylinder. As a hydraulic control valve, there is a hydraulic control valve that includes: a valve body having a plurality of passages; and a check valve that prevents the working oil supplied to the valve body from flowing back (for example, refer to Patent Document 1). For example, in Patent Document 1, in order to improve the maintainability of the valve body, four check valves are respectively arranged on the connecting surface of the valve body.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-141858 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, when the four check valves are arranged on the same surface (the connection surface of the valve body), a wide connection area of ​​the valve body must be ensured. Therefore, there is room for improvement in miniaturizing the valve body.

[0008] 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, and a construction machine in which a valve body can be miniaturized.

[0009] Solutions for solving problems

[0010] As a solution to the above-mentioned problem, the present invention has the following configuration.

[0011] (1) A fluid control valve according to an embodiment of the present invention comprises: a first check valve capable of allowing fluid to pass from a first pump passage to a bridge supply passage; a second check valve capable of allowing fluid to pass from a second pump passage to the bridge supply passage; and a third check valve capable of allowing fluid to pass from a third pump passage to the bridge supply passage.

[0012] This structure provides three check valves that allow fluid to flow from three pump passages to a single bridge-type supply passage. This reduces the space required for the check valves compared to systems with four or more check valves. Furthermore, compared to systems with four or more check valves positioned on the same surface, there is no need to ensure a wide connection area within the valve body. Consequently, the valve body can be miniaturized.

[0013] (2) In the fluid control valve described in (1) above, the first plug of the first check valve may support a portion of the third check valve, and the second plug of the second check valve may support another portion of the third check valve.

[0014] (3) In the fluid control valve described in (1) or (2) above, the first pump passage may include a first branch passage capable of supplying fluid to the bridge supply passage and a second branch passage capable of supplying fluid to the bridge supply passage.

[0015] (4) In the fluid control valve described in (1) or (2) above, the second pump passage may include a third branch passage capable of supplying fluid to the bridge supply passage and a fourth branch passage capable of supplying fluid to the bridge supply passage.

[0016] (5) In the fluid control valve described in (3) above, the first check valve may also include: a first branch passage valve that allows fluid to pass from the first branch passage to the bridge supply passage; and a second branch passage valve that allows fluid to pass from the second branch passage to the bridge supply passage.

[0017] (6) In the fluid control valve described in (4) above, the second check valve may also include: a valve for a third branch passage, which can allow fluid to pass from the third branch passage to the bridge supply passage; and a valve for a fourth branch passage, which can allow fluid to pass from the fourth branch passage to the bridge supply passage.

[0018] (7) In the fluid control valve described in (5) above, it may also be that the first branch passage valve has a main body having a central hole along the axis, the first branch passage valve has a first inclined surface, the first inclined surface is arranged on the outer periphery of the main body and crosses obliquely relative to the axis, and the second branch passage valve has a shaft member configured to be movable in an axial direction parallel to the axis relative to the central hole, the second branch passage valve has a second inclined surface, the second inclined surface is arranged on the outer periphery of the shaft member and crosses obliquely relative to the axis.

[0019] (8) The fluid control valve of the present invention comprises: a first check valve capable of allowing fluid to pass from a first pump passage to a bridge supply passage, the first pump passage having a first branch passage capable of supplying fluid to the bridge supply passage and a second branch passage capable of supplying fluid to the bridge supply passage, the first check valve comprising a first branch passage valve capable of allowing fluid to pass from the first branch passage to the bridge supply passage and a second branch passage valve capable of allowing fluid to pass from the second branch passage to the bridge supply passage, the first branch passage valve comprising a main body having a central hole along an axis, the first branch passage valve comprising a first inclined surface which is arranged on the outer periphery of the main body and crosses obliquely with respect to the axis, the second branch passage valve comprising an axial structure which is configured to be movable relative to the central hole in an axial direction parallel to the axis. The cam is connected to the second pump passage through the cam, and the cam is connected to the second pump passage through the cam, and the cam is connected to the second pump passage through the cam.

[0020] According to this structure, there are three check valves that can allow fluid to pass from three pump passages to a bridge-type supply passage, thereby achieving space saving for the installation space of the check valves compared to the case of having four or more check valves. In addition, compared to the case where four or more check valves are respectively arranged on the same surface, there is no need to ensure that the connection area of ​​the valve body is wider. Therefore, the valve body can be miniaturized. In addition, the valve for the first branch passage and the valve for the second branch passage are arranged on the same axis, so the first check valve can be miniaturized compared to the case where multiple valves are respectively arranged on the same surface. In addition, a part of the third check valve is supported by the first plug, and the other part of the third check valve is supported by the second plug, so the third check valve can be firmly supported. In addition, compared to the case where the third check valve is fixed by a thread, space saving can be achieved.

[0021] (9) A fluid control valve according to a form of the present invention comprises: a first check valve capable of allowing fluid to pass from a first pump passage to a bridge supply passage, the first pump passage having a first branch passage capable of supplying fluid to the bridge supply passage and a second branch passage capable of supplying fluid to the bridge supply passage, the first check valve comprising a first branch passage valve capable of allowing fluid to pass from the first branch passage to the bridge supply passage and a second branch passage valve capable of allowing fluid to pass from the second branch passage to the bridge supply passage, the first branch passage valve comprising a main body having a central hole along an axis, the first branch passage valve comprising: a first inclined surface arranged on the outer periphery of the main body and obliquely intersecting with respect to the axis; and a partition member arranged on the inner periphery of the main body and dividing the central hole into one side and the other side axially parallel to the axis, the second branch passage valve comprising a valve configured to be able to pass relative to the main body. For the shaft component whose central hole moves in the axial direction, the second branch passage valve has a second inclined surface, which is arranged on the outer periphery of the shaft component and crosses obliquely relative to the axis; a second check valve, which can allow fluid to pass from the second pump passage to the bridge supply passage, the second pump passage has a third branch passage that can supply fluid to the bridge supply passage and a fourth branch passage that can supply fluid to the bridge supply passage, the second check valve has a third branch passage valve that can allow fluid to pass from the third branch passage to the bridge supply passage and a fourth branch passage valve that can allow fluid to pass from the fourth branch passage to the bridge supply passage; and a third check valve, which can allow fluid to pass from the third pump passage to the bridge supply passage, a part of the third check valve is supported by the first plug of the first check valve, and the other part of the third check valve is supported by the second plug of the second check valve.

[0022] According to this structure, there are three check valves that can allow fluid to pass from three pump passages to a bridge-type supply passage, thereby achieving space saving for the installation space of the check valves compared to the case of having four or more check valves. In addition, compared to the case where four or more check valves are respectively arranged on the same surface, there is no need to ensure that the connection area of ​​the valve body is wider. Therefore, the valve body can be miniaturized. In addition, the valve for the first branch passage and the valve for the second branch passage are arranged on the same axis, so the first check valve can be miniaturized compared to the case where multiple valves are respectively arranged on the same surface. In addition, a part of the third check valve is supported by the first plug, and the other part of the third check valve is supported by the second plug, so the third check valve can be firmly supported. In addition, compared to the case where the third check valve is fixed by a thread, space saving can be achieved. Furthermore, a partition is provided on the inner periphery of the main body of the first check valve to divide the central hole into one side and the other side in the axial direction, so that the partition can restrict the axial movement of the shaft member relative to the central hole.

[0023] (10) The fluid system of the present invention comprises: a fluid control valve, which comprises: a first check valve, which can allow fluid to pass from the first pump passage to the bridge supply passage; a second check valve, which can allow fluid to pass from the second pump passage to the bridge supply passage; and a third check valve, which can allow fluid to pass from the third pump passage to the bridge supply passage; a fluid supply source, which supplies fluid to the first pump passage, the second pump passage and the third pump passage; and a driving body, which is driven by the fluid.

[0024] This structure provides three check valves that allow fluid to flow from three pump passages to a single bridge-type supply passage. This reduces the space required for the check valves compared to systems with four or more check valves. Furthermore, compared to systems with four or more check valves positioned on the same surface, there is no need to ensure a wide connection area within the valve body. Consequently, the valve body can be miniaturized.

[0025] (11) In the fluid system described in (10) above, it is also possible that the fluid supply source is provided in plurality, and the plurality of fluid supply sources respectively include: a first pump, which supplies fluid to the first pump passage; a second pump, which supplies fluid to the second pump passage; and a third pump, which supplies fluid to the third pump passage.

[0026] (12) In the fluid system described in (10) or (11) above, the first pump passage may have a first branch passage and a second branch passage, the first branch passage being a parallel passage capable of supplying fluid to the bridge supply passage, and the second branch passage being a series passage capable of supplying fluid to the bridge supply passage.

[0027] (13) The construction machinery of the present invention comprises: a fluid control valve, which comprises: a first check valve, which can allow fluid to pass from the first pump passage to the bridge supply passage; a second check valve, which can allow fluid to pass from the second pump passage to the bridge supply passage; and a third check valve, which can allow fluid to pass from the third pump passage to the bridge supply passage; a fluid supply source, which supplies fluid to the first pump passage, the second pump passage and the third pump passage; and a driving body, which is driven by the fluid.

[0028] This structure provides three check valves that allow fluid to flow from three pump passages to a single bridge-type supply passage. This reduces the space required for the check valves compared to systems with four or more check valves. Furthermore, compared to systems with four or more check valves positioned on the same surface, there is no need to ensure a wide connection area within the valve body. Consequently, the valve body can be miniaturized.

[0029] Effects of the Invention

[0030] According to the present invention, a fluid control valve, a fluid system, and a construction machine capable of reducing the size of a valve body can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2 It is a plan view of the hydraulic control valve according to the first embodiment.

[0033] Figure 3 is included Figure 2 Schematic diagram of the hydraulic system in section III-III.

[0034] Figure 4 is included Figure 3 Schematic diagram of the check valve with an enlarged view of the main parts.

[0035] Figure 5 yes Figure 4 VV cross-sectional view of.

[0036] Figure 6 It is a schematic diagram of the first branch passage valve in the first embodiment.

[0037] Figure 7 This is a schematic diagram of the second branch passage valve in the first embodiment.

[0038] Figure 8 This is an explanatory diagram of an example of the operation of the first check valve in the first embodiment.

[0039] Figure 9 This is an explanatory diagram of another example of the operation of the first check valve in the first embodiment.

[0040] Figure 10 This is an explanatory diagram of an example of the operation of the third check valve in the first embodiment.

[0041] Figure 11 This is a block diagram of the hydraulic system according to the first embodiment.

[0042] Figure 12 It is a schematic diagram of a second branch passage valve according to a modified example of the first embodiment.

[0043] Figure 13 It is a schematic diagram of the check valve of the second embodiment.

[0044] Description of Reference Numerals

[0045] 1. Construction machinery; 10. Hydraulic system (fluid system); 11. Hydraulic control valve (fluid control valve); 12. Hydraulic pump (fluid supply source); 13. Hydraulic actuator (driving body); 18. Plug; 18A, first plug; 18B, second plug; 20. Check valve; 20A, first check valve (check valve); 20B, second check valve (check valve); 20C, third check valve (check valve); 21A, first branch passage valve; 21B, third branch passage valve; 22A, second branch passage valve; 22B, fourth branch passage valve Valve; 35, 1st pump passage; 35a, 1st branch passage; 35b, 2nd branch passage; 36, 2nd pump passage; 36a, 3rd branch passage; 36b, 4th branch passage; 37, 3rd pump passage; 38, bridge supply passage; 50, central hole; 51, main body; 52, 1st inclined surface; 60, shaft member; 61, 2nd inclined surface; 81, 1st pump; 82, 2nd pump; 83, 3rd pump; 221A, valve for 1st branch passage; 257, partition; C1, 1st axis (axis); C2, 2nd axis; C3, 3rd axis. DETAILED DESCRIPTION

[0046] The following describes embodiments of the present invention with reference to the accompanying drawings. In the following embodiments, a hydraulic excavator equipped with a hydraulic system (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 make it recognizable.

[0047] [First embodiment]

[0048] [Construction machinery]

[0049] Figure 1 It is a schematic diagram of the construction machine 1 according to the first embodiment.

[0050] For example, construction machine 1 is a hydraulic excavator. Construction machine 1 includes a revolving body 2 and a traveling body 3. Revolving body 2 is rotatably mounted on traveling body 3. Revolving body 2 includes a hydraulic pump 12 (fluid supply source) that supplies hydraulic oil (fluid) to a first pump passage 35, a second pump passage 36, and a third pump passage 37.

[0051] The revolving structure 2 includes a cab 5 in which an operator can sit; a boom 6 having one end swingably connected to the cab 5; an arm 7 having one end swingably connected to the other end (top end) of the boom 6 on the side opposite the cab 5; and a bucket 8 swingably connected to the other end (top end) of the arm 7 on the side opposite the boom 6. A hydraulic pump 12 is disposed 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 to a first pump passage 35, a second pump passage 36, and a third pump passage 37.

[0052] [Hydraulic system]

[0053] Figure 2 It is a plan view of the hydraulic control valve 11 according to the first embodiment. Figure 3 is included Figure 2 Schematic diagram of the hydraulic system 10 in section III-III.

[0054] like Figure 3 As shown in FIG, the hydraulic system 10 includes a hydraulic control valve 11 (fluid control valve), 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 In the figure, a hydraulic cylinder is shown as the hydraulic actuator 13. Reference numeral 14 in the figure denotes a tank for storing hydraulic oil.

[0055] [Hydraulic control valve]

[0056] The hydraulic control valve 11 controls the supply and discharge of hydraulic oil to and from the hydraulic cylinder 13. The hydraulic control valve 11 includes a plurality of (for example, three in this embodiment) check valves 20, a valve body 30 having a plurality of passages 31 to 38, and a spool 40. The hydraulic control valve 11 is a spool-type reversing valve.

[0057] The plurality of passages 31 to 38 are flow passages (oil passages) for the flow of hydraulic oil. The plurality of passages 31 to 38 include the spool hole 31, the first actuator passage 32, the second actuator passage 33, the tank passage 34, the first pump passage 35, the second pump passage 36, the third pump passage 37, and the bridge supply passage 38.

[0058] The spool hole 31 is a hole into which the spool 40 can be inserted. The spool hole 31 extends in a direction substantially perpendicular to the axis C1 of the check valve 20 ( Figure 3The spool 40 extends through the valve body 30 (in the left-right direction and the direction of the opening of the spool hole 31). A spool 40 is removably inserted into the spool hole 31. The spool 40 extends in the direction of the opening of the spool hole 31. The spool 40 has a plurality of lands 41 that can contact the inner circumferential surface of the spool hole 31. The spool 40 moves in the direction of the opening of the spool hole 31, opening and closing the flow path and performing throttling operations. The flow rate of hydraulic oil supplied to the hydraulic cylinder is controlled by the position of the spool 40.

[0059] In the figure, reference numeral 42 indicates a coil spring for maintaining the valve column 40 in a predetermined position (for example, a return spring for returning the valve column 40 to a neutral position), reference numeral 43 indicates a first pilot port provided to one end side of the valve column 40, and reference numeral 44 indicates a second pilot port provided to the other end side of the valve column 40.

[0060] The first actuator passage 32 is arranged on one side of the check valve 20. The first actuator passage 32 extends in a direction substantially 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 port (e.g., rod side oil chamber) of the hydraulic cylinder 13. The other end ( Figure 3 The lower end of the valve stem is connected to the valve stem hole 31.

[0061] 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 arranged in a direction substantially parallel to the first actuator passage 32 ( Figure 3 One end of the second actuator passage 33 ( Figure 3 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.

[0062] The tank passage 34 branches from the spool hole 31. The tank passage 34 includes a first tank path 34a located to the side of the first actuator passage 32 and extending substantially parallel to the first actuator passage 32 ( Figure 3 a second box path 34b, which is located on the side of the second actuator passage 33, and along a direction substantially parallel to the first box path 34a ( Figure 3 and a third box path 34c, which extends in a direction substantially parallel to the opening direction of the spool hole 31, connecting one end of the first box path 34a ( Figure 3 The lower end of the second tank path 34b and one end of the second tank path 34b ( Figure 3The third tank path 34c is arranged on the opposite side of the check valve 20 across the spool hole 31.

[0063] The first pump passage 35 is located at a position overlapping the first check valve 20A. The first pump passage 35 is located on the opposite side of the third tank passage 34c across the spool hole 31. The first pump passage 35 includes a first branch passage 35a capable of supplying hydraulic oil to the bridge supply passage 38, and a second branch passage 35b capable of supplying hydraulic oil to the bridge supply passage 38.

[0064] The first branch passage 35a is a parallel passage for connecting a plurality of flow passages in parallel. That is, the hydraulic oil passing through the first branch passage 35a is supplied in parallel (simultaneously) to a plurality of subsections (not shown).

[0065] The second branch passage 35b is located near the spool hole 31. It is located between the first branch passage 35a and the spool hole 31. The second branch passage 35b is a series passage that connects multiple flow paths in series. Specifically, the hydraulic oil passing through the second branch passage 35b is supplied sequentially (from upstream to downstream in the direction of the working fluid) to multiple subsections (not shown).

[0066] The second pump passage 36 is located at a position overlapping the second check valve 20B. It is located on the opposite side of the third tank passage 34c across the spool hole 31. The second pump passage 36 includes a third branch passage 36a capable of supplying hydraulic oil to the bridge supply passage 38, and a fourth branch passage 36b capable of supplying hydraulic oil to the bridge supply passage 38. For example, the third branch passage 36a is a parallel passage. For example, the fourth branch passage 36b is a series passage.

[0067] The third pump passage 37 is located at a position overlapping the third check valve 20C. The third pump passage 37 is located on the opposite side of the third tank path 34c across the spool hole 31. The third pump passage 37 is a passage capable of supplying hydraulic oil to the bridge supply passage 38. For example, the third pump passage 37 is a parallel passage.

[0068] The bridge supply passage 38 is disposed between the first branch passage 35a and the second branch passage 35b, and between the third branch passage 36a and the fourth branch passage 36b. The bridge supply passage 38 has an inverted U-shape in cross-section. The midway portion of the bridge supply passage 38 connects to the first pump passage 35, the second pump passage 36, and the third pump passage 37. Both ends of the bridge supply passage 38 are connected to the spool hole 31. The bridge supply passage 38 bridges the first pump passage 35, the second pump passage 36, and the third pump passage 37.

[0069] [Check valve]

[0070] The check valve 20 is opened along the valve stem 40 ( Figure 3 A plurality of check valves 20 (for example, three in this embodiment) are arranged in an array (in the left-right direction). Two of the three check valves 20 are positioned adjacent to each other across the wall 30a of the valve body 30. The three check valves 20 are a first check valve 20A that allows hydraulic oil to flow from the first pump passage 35 to the bridge supply passage 38; a second check valve 20B that allows hydraulic oil to flow from the second pump passage 36 to the bridge supply passage 38; and a third check valve 20C that allows hydraulic oil to flow from the third pump passage 37 to the bridge supply passage 38.

[0071] The first check valve 20A is located near the first actuator passage 32. The first check valve 20A includes a first branch passage valve 21A that allows hydraulic oil to flow from the first branch passage 35a to the bridge supply passage 38, and a second branch passage valve 22A that allows hydraulic oil to flow from the second branch passage 35b to the bridge supply passage 38. The first branch passage valve 21A and the second branch passage valve 22A are arranged along the axis C1.

[0072] The second check valve 20B is located near the second actuator passage 33. The second check valve 20B is arranged in parallel with the first check valve 20A in a direction perpendicular to the axis C1. The second check valve 20B includes a third branch passage valve 21B that allows hydraulic oil to flow from the third branch passage 36a to the bridge supply passage 38, and a fourth branch passage valve 22B that allows hydraulic oil to flow from the fourth branch passage 36b to the bridge supply passage 38. The third branch passage valve 21B and the fourth branch passage valve 22B are arranged along the axis C2.

[0073] The third check valve 20C is disposed between the first check valve 20A and the second check valve 20B. In the figure, reference numeral 18 denotes a plug covering the end of the check valve 20, and reference numeral 19 denotes an O-ring installed in the groove of the plug 18. The following describes the first check valve 20A of the two check valves 20A and 20B. Since the second check valve 20B has the same structure as the first check valve 20A, a detailed description thereof will be omitted.

[0074] like Figure 4As shown, the first check valve 20A includes a first branch passage valve 21A, a second branch passage valve 22A, and elastic members 24 and 25. The first branch passage valve 21A and the second branch passage valve 22A share a common axis C1. That is, the first branch passage valve 21A and the second branch passage valve 22A are coaxially arranged with respect to each other. Hereinafter, the direction parallel to the axis C1 will also be referred to as the "axial direction," and the direction orthogonal to the axial direction will also be referred to as the "radial direction." The first check valve 20A is axially arranged at a position where the first branch passage 35a and the second branch passage 35b are opposite each other across the bridge supply passage 38.

[0075] [Valve for the first branch passage]

[0076] The first branch passage valve 21A blocks or connects the first branch passage 35a and the bridge supply passage 38. Figure 4 In the embodiment, the first branch passage valve 21A blocks the first branch passage 35a and the bridge supply passage 38. The first branch passage valve 21A includes a main body 51 having a central hole 50 extending along the axis C1. The first branch passage valve 21A has a first inclined surface 52 disposed on the outer periphery of the main body 51 and obliquely intersecting the axis C1. The first branch passage valve 21A has a narrowed portion 53 disposed axially offset from the first inclined surface 52 to allow the passage of hydraulic oil.

[0077] The central hole 50 is open in the entire body 51 in the axial direction. The central hole 50 has a first inlet 50a for the shaft member 60 of the second branch passage valve 22A to enter; a second inlet 50b located axially inward of the first inlet 50a and larger than the first inlet 50a; and a third inlet 50c located axially inward of the second inlet 50b and larger than the second inlet 50b (see FIG. Figure 6 The shaft member 60 of the second branch passage valve 22A enters the first inlet 50a, the second inlet 50b, and the third inlet 50c in this order. The third inlet 50c also functions as a spring receiving portion where the elastic members 24 and 25 (coil springs) are disposed.

[0078] The first inclined surface 52 is disposed on the outer periphery of the second inlet 50b in the main body 51. The first inclined surface 52 extends over the entire outer periphery of the main body 51. The first inclined surface 52 has an annular shape when viewed axially. The first inclined surface 52 gradually decreases in diameter inward from the first branch passage 35a toward the bridge supply passage 38.

[0079] The narrowed portion 53 is disposed on the outer periphery of the first inlet 50a in the main body 51. The narrowed portion 53 is disposed closer to the bridge supply passage 38 than the first inclined surface 52. The narrowed portion 53 has a cylindrical shape with a smaller outer shape than the first inclined surface 52. The narrowed portion 53 has an outer diameter smaller than the minimum outer diameter of the first inclined surface 52 (the outer diameter of the end portion on the bridge supply passage 38 side).

[0080] [Valve for the second branch passage]

[0081] The second branch passage valve 22A blocks or connects the second branch passage 35b and the bridge supply passage 38. Figure 4 In the embodiment, the second branch passage valve 22A blocks the second branch passage 35b and the bridge supply passage 38. The second branch passage valve 22A includes a shaft member 60 arranged to be movable in the axial direction relative to the central hole 50; a second inclined surface 61 provided on the outer periphery of the shaft member 60 and obliquely intersecting the axis C1; and a protrusion 62 protruding radially from the shaft member 60.

[0082] The second inclined surface 61 is disposed on the outer periphery of the end portion of the shaft member 60 on the second branch passage 35b side. The second inclined surface 61 extends over the entire outer periphery of the shaft member 60. The second inclined surface 61 has an annular shape when viewed axially. The second inclined surface 61 gradually increases in radial direction outward from the second branch passage 35b side toward the bridge supply passage 38 side.

[0083] The protrusion 62 is provided at the end portion of the shaft member 60 on the side opposite to the second inclined surface 61. The protrusion 62 is provided on the entire outer circumference of the shaft member 60. The protrusion 62 has an annular shape when viewed from the axial direction. The protrusion 62 has an outer shape that is substantially the same as the first inlet 50a when viewed from the axial direction. "Substantially the same" means that the outer shape of the protrusion 62 is substantially the same as that of the first inlet 50a within the allowable range of the design error (dimensional error) of the check valve 20. "Substantially the same" includes the case where the outer shape of the protrusion 62 is exactly the same as that of the first inlet 50a.

[0084] In the embodiment, the outer diameter D1 of the protrusion 62 (see Figure 7 ) and the inner diameter D2 of the first inlet 50a (refer to Figure 6 ) are substantially the same (D1≈D2). The outer diameter D1 of the protrusion 62 refers to the outer diameter of the end portion of the protrusion 62 on the side of the second inclined surface 61. The inner diameter D2 of the first inlet 50a refers to the inner diameter of the portion of the first inlet 50a adjacent to the second inlet 50b.

[0085] In the embodiment, the first check valve 20A has a fluid passage 23 (see Figure 5 ).like Figure 5As shown, fluid passage 23 is provided between the inner periphery of central bore 50 and the outer periphery of shaft member 60. Fluid passage 23 is a flow path through which hydraulic oil can flow in the axial direction. Shaft member 60 has a D-cut surface 60a formed by cutting away a portion of its outer periphery. Fluid passage 23 is defined by D-cut surface 60a of shaft member 60 and the inner periphery of central bore 50 (the portion facing D-cut surface 60a).

[0086] [Elastic member]

[0087] like Figure 4 As shown, elastic members 24 and 25 are provided in the first check valve 20A. In this embodiment, the number of elastic members is two, but a plurality of elastic members, three or more, may be provided. The plurality of elastic members 24 and 25 are a first coil spring 24 that elastically supports the first branch passage valve 21A, and a second coil spring 25 that elastically supports the second branch passage valve 22A. The first coil spring 24 and the second coil spring 25 are arranged at the third inlet 50c. The first coil spring 24 and the second coil spring 25 are elastically deformable in the axial direction. The first coil spring 24 and the second coil spring 25 are arranged in a position where they are pressed only from one side in the axial direction.

[0088] The first coil spring 24 is disposed between the main body 51 of the first branch passage valve 21A and the plug 18. The first coil spring 24 constantly presses the first branch passage valve 21A toward the bridge supply passage 38, causing the first branch passage valve 21A to block the first branch passage 35a and the bridge supply passage 38. Hereinafter, the force exerted by the first coil spring 24 to press the first branch passage valve 21A toward the bridge supply passage 38 is also referred to as the "first spring force."

[0089] The second coil spring 25 is positioned between the protrusion 62 of the second branch passage valve 22A and the plug 18. The second coil spring 25 has an axially smaller outer shape than the first coil spring 24. The second coil spring 25 is positioned radially inward of the first coil spring 24. The second coil spring 25 constantly presses the second branch passage valve 22A toward the second branch passage 35b, causing the second branch passage valve 22A to block the second branch passage 35b from the bridge supply passage 38. Hereinafter, the force exerted by the second coil spring 25 to press the second branch passage valve 22A toward the second branch passage 35b is also referred to as the "second spring force."

[0090] [Operation of the first check valve]

[0091] Figure 8 It is an explanatory diagram of an example of the operation of the first check valve 20A in the first embodiment. Figure 8 FIG. 3 shows a situation where hydraulic oil is supplied from the second branch passage 35b to the bridge supply passage 38. Figure 8In the figure, the solid line shows the state where the second branch passage valve 22A connects the second branch passage 35b and the bridge supply passage 38, and the two-dot chain line shows the state where the second branch passage valve 22A blocks the second branch passage 35b and the bridge supply passage 38.

[0092] like Figure 8 As shown, when the hydraulic oil is supplied from the second branch passage 35b to the bridge supply passage 38, the second branch passage valve 22A is axially closed from the second inclined surface 61 side ( Figure 8 At this time, if the second branch passage valve 22A is pushed axially from the side opposite to the first branch passage valve 21A with a force stronger than the second spring force, the second branch passage valve 22A overcomes the second coil spring 25 and moves to the Figure 8 That is, when the working oil is supplied from the second branch passage 35b to the bridge supply passage 38, the second branch passage valve 22A moves toward the inside of the bridge supply passage 38. As a result, the working oil flows from the second branch passage 35b toward the bridge supply passage 38 ( Figure 8 in the direction of arrow K1).

[0093] Figure 9 This is an explanatory diagram of another example of the operation of the first check valve 20A according to the first embodiment. Figure 9 FIG. 3 shows a situation where hydraulic oil is supplied from the first branch passage 35a to the bridge supply passage 38. Figure 9 In the figure, the solid line shows the state where the first branch passage valve 21A connects the first branch passage 35a and the bridge supply passage 38, and the two-dot chain line shows the state where the first branch passage valve 21A blocks the first branch passage 35a and the bridge supply passage 38.

[0094] like Figure 9 As shown, when the hydraulic oil is supplied from the first branch passage 35a to the bridge supply passage 38, the first branch passage valve 21A is axially closed from the first inclined surface 52 side ( Figure 9 At this time, part of the working oil flowing in the bridge supply passage 38 passes through the fluid passage 23 (refer to Figure 5 ), acting on the back side of the first branch passage valve 21A (the upper end of the main body 51) ( Figure 9 The first branch passage valve 21A is pushed to the right by a predetermined pressure (hereinafter also referred to as "bridge pressure") Figure 9 If the first branch passage valve 21A is pushed from the first inclined surface 52 side in the axial direction with a force stronger than the bridge pressure, the first branch passage valve 21A overcomes the first coil spring 24 and moves to the Figure 9That is, when the hydraulic oil is supplied from the first branch passage 35a to the bridge supply passage 38, the first branch passage valve 21A moves in a direction away from the bridge supply passage 38. As a result, the hydraulic oil flows from the first branch passage 35a to the bridge supply passage 38 ( Figure 9 direction of arrow K3).

[0095] [3rd check valve]

[0096] like Figure 4 As shown, the third check valve 20C is arranged between the first check valve 20A and the second check valve 20B. From the axial point of view, the third check valve 20C is arranged at a position offset from the first check valve 20A and the second check valve 20B (refer to FIG. Figure 2 In the figure, reference numeral C1 represents the central axis of the first check valve 20A (hereinafter also referred to as the "first axis"), reference numeral C2 represents the central axis of the second check valve 20B (hereinafter also referred to as the "second axis"), and reference numeral C3 represents the central axis of the third check valve 20C (hereinafter also referred to as the "third axis"). From an axial point of view, the third axis C3 is arranged at a central position between the first axis C1 and the second axis C2, and is offset in a direction orthogonal to the line segment connecting the first axis C1 and the second axis C2 (refer to Figure 2 ).

[0097] Hereinafter, the plug covering the first check valve 20A is also referred to as the "first plug", the plug covering the second check valve 20B is also referred to as the "second plug", and the plug covering the third check valve 20C is also referred to as the "third plug". The first plug 18A and the second plug 18B are arranged from one side in the axial direction ( Figure 4 The first plug 18A supports one side portion of the third check valve 20C ( Figure 4 The second plug 18B supports the other side of the third check valve 20C ( Figure 4 That is, the third check valve 20C is supported from above and from both left and right sides by a pair of plugs 18A and 18B.

[0098] The third check valve 20C blocks or connects the third pump passage 37 and the bridge supply passage 38. Figure 4 In the embodiment of the present invention, the third check valve 20C blocks the third pump passage 37 and the bridge supply passage 38. The third check valve 20C includes a fifth passage valve 70 and a third coil spring 71 that elastically supports the fifth passage valve 70 in the axial direction. The fifth passage valve 70 includes a valve element 72 that is movable in the axial direction of the third axis C3. The fifth passage valve 70 has a third inclined surface 73 that is provided on the outer periphery of the valve element 72 and obliquely intersects the third axis C3.

[0099] The third inclined surface 73 is disposed on the outer periphery of the end portion of the valve element 72 on the third pump passage 37 side. The third inclined surface 73 extends over the entire outer periphery of the valve element 72. The third inclined surface 73 has an annular shape when viewed axially. The third inclined surface 73 gradually increases in radial direction outward from the third pump passage 37 side toward the bridge supply passage 38 side.

[0100] The valve element 72 includes a recessed portion 72a in which the third coil spring 71 is disposed, and a communication hole 72b that connects the interior of the recessed portion 72a with the bridge supply passage 38. The recessed portion 72a is provided at the end portion on the opposite side of the third inclined surface 73 in the axial direction. The communication hole 72b extends in a direction obliquely intersecting the third axis C3.

[0101] The third coil spring 71 is disposed between the valve element 72 of the fifth passage valve 70 and the third plug 18C. The third coil spring 71 constantly presses the fifth passage valve 70 toward the third pump passage 37 so that the fifth passage valve 70 blocks the bridge supply passage 38. Hereinafter, the force exerted by the third coil spring 71 to press the fifth passage valve 70 toward the third pump passage 37 is also referred to as the "third spring force."

[0102] [Operation of the 3rd check valve]

[0103] Figure 10 It is an explanatory diagram of an example of the operation of the third check valve 20C in the first embodiment. Figure 10 FIG. 3 shows a situation where hydraulic oil is supplied from the third pump passage 37 to the bridge supply passage 38. Figure 10 In FIG. 1 , a state where the fifth passage valve 70 connects the third pump passage 37 and the bridge supply passage 38 is shown by a solid line, and a state where the fifth passage valve 70 blocks the third pump passage 37 and the bridge supply passage 38 is shown by a two-dot chain line.

[0104] like Figure 10 As shown, when the hydraulic oil is supplied from the third pump passage 37 to the bridge supply passage 38, the fifth passage valve 70 is axially closed from the third inclined surface 73 side ( Figure 10 At this time, if the fifth passage valve 70 is pushed from the side opposite to the third plug 18C in the axial direction with a force stronger than the third spring force, the fifth passage valve 70 overcomes the third coil spring 71 and moves to the Figure 10 That is, when the working oil is supplied from the third pump passage 37 to the bridge supply passage 38, the fifth passage valve 70 moves toward the inside of the bridge supply passage 38. As a result, the working oil flows from the third pump passage 37 toward the bridge supply passage 38 ( Figure 10 The working oil flows along the bridge supply passage 38 ( Figure 10 in the direction of arrow K5).

[0105] [Application example of hydraulic system]

[0106] Figure 11 1 is a block diagram of the hydraulic system 10 according to the first embodiment. Figure 11 As shown, the hydraulic system 10 includes multiple hydraulic pumps 81 to 83. The multiple hydraulic pumps 81 to 83 include a first pump 81, a second pump 82, and a third pump 83. The first pump 81 is a turning pump. The second pump 82 is a driving pump (e.g., for left-hand driving). The third pump 83 is a driving pump (e.g., for right-hand driving).

[0107] The hydraulic system 10 includes a merging valve 90 (e.g., corresponding to the third check valve 20C). This merging valve 90 blocks or connects a first merging passage 85 (e.g., corresponding to the first pump passage 35) capable of supplying hydraulic fluid from the first pump 81, a second merging passage 86 (e.g., corresponding to the second pump 36) capable of supplying hydraulic fluid from the second pump 82, and a third merging passage 87 (e.g., corresponding to the third pump passage 37) capable of supplying hydraulic fluid from the third pump 83. This allows the hydraulic fluid supplied from the three pumps 81 to 83 to merge in any of the first merging passage 85, the second merging passage 86, and the third merging passage 87.

[0108] As described above, the hydraulic control valve 11 of this embodiment includes: a first check valve 20A that allows the hydraulic oil to flow from the first pump passage 35 to the bridge supply passage 38; the first pump passage 35 includes a first branch passage 35a that can supply the hydraulic oil to the bridge supply passage 38; and a second branch passage 35b that can supply the hydraulic oil to the bridge supply passage 38; the first check valve 20A includes a first branch passage valve 20A that allows the hydraulic oil to flow from the first branch passage 35a to the bridge supply passage 38. 1A and a second branch passage valve 22A capable of passing the working oil from the second branch passage 35b to the bridge supply passage 38, the first branch passage valve 21A includes a main body 51, the main body 51 having a central hole 50 along the axis C1, the first branch passage valve 21A has a first inclined surface 52, the first inclined surface 52 is provided on the outer periphery of the main body 51 and crosses obliquely with respect to the axis C1, the second branch passage valve 22A includes a shaft member 60 configured to be movable in the axial direction relative to the central hole 50, The second branch passage valve 22A has a second inclined surface 61, which is provided on the outer periphery of the shaft member 60 and crosses obliquely with respect to the axis C1; the second check valve 20B, which can allow the working oil to pass from the second pump passage 36 to the bridge supply passage 38, the second pump passage 36 having a third branch passage 36a capable of supplying working oil to the bridge supply passage 38 and a fourth branch passage 36b capable of supplying working oil to the bridge supply passage 38, the second check valve 20B has a function of allowing the working oil to pass from the second pump passage 36 to the bridge supply passage 38. The third branch passage 36a includes a third branch passage valve 21B that connects the third branch passage 36a to the bridge supply passage 38, and a fourth branch passage valve 22B that allows hydraulic oil to flow from the fourth branch passage 36b to the bridge supply passage 38; and a third check valve 20C that allows hydraulic oil to flow from the third pump passage 37 to the bridge supply passage 38. A portion of the third check valve 20C is supported by the first plug 18A of the first check valve 20A, and the other portion of the third check valve 20C is supported by the second plug 18B of the second check valve 20B.

[0109] This structure provides three check valves 20A-20C, allowing hydraulic oil to flow from three pump passages 35-37 to a single bridge supply passage 38. This reduces the installation space required for the check valves 20A-20C compared to a system with four or more check valves. Furthermore, compared to a system with four or more check valves positioned on the same surface, there is no need to ensure a wide connection area for the valve body 30. Consequently, the valve body 30 can be made more compact. Furthermore, since the first branch passage valve 21A and the second branch passage valve 22A are positioned on the same axis, the first check valve 20A can be made more compact compared to a system with multiple valves positioned on the same surface. Furthermore, a portion of the third check valve 20C is supported by the first plug 18A, while the remaining portion is supported by the second plug 18B. This ensures that the third check valve 20C is securely supported. Furthermore, compared with the case where the third check valve 20C is fixed with screws, space saving can be achieved.

[0110] In the present embodiment, the first branch passage valve 21A includes the narrowed portion 53 , which is disposed at a position offset from the first inclined surface 52 in the axial direction and allows the hydraulic oil to pass therethrough.

[0111] According to this structure, the first inclined surface 52 and the narrowing portion 53 are arranged at positions offset in the axial direction, so that compared with the case where the first inclined surface 52 also serves as the narrowing portion (for example, a concave and convex surface is provided on the first inclined surface to allow the working oil to pass through), complicated processing is not required and low cost can be achieved.

[0112] In the present embodiment, the narrowed portion 53 has a cylindrical shape whose outer shape is smaller than that of the first inclined surface 52 .

[0113] According to this configuration, the hydraulic oil can be smoothly passed along the outer periphery of the narrowed portion 53 .

[0114] In the present embodiment, elastic members 24 and 25 are provided that elastically support the first branch passage valve 21A and the second branch passage valve 22A in the axial direction and are arranged at positions where they are pressed only from one side in the axial direction.

[0115] According to this structure, the elastic members 24 and 25 are pressed only from one side in the axial direction. Therefore, it is easier to manage the elastic forces of the elastic members 24 and 25 than in a case where the elastic members are pressed from both sides in the axial direction.

[0116] In the present embodiment, a plurality of elastic members 24 and 25 are provided. The plurality of elastic members 24 and 25 are a first coil spring 24 elastically supporting the first branch passage valve 21A and a second coil spring 25 elastically supporting the second branch passage valve 22A.

[0117] According to this configuration, the first branch passage valve 21A and the second branch passage valve 22A are supported separately, and therefore the first branch passage valve 21A and the second branch passage valve 22A can be managed separately with high precision.

[0118] In the present embodiment, the central hole 50 opens in the entire body 51 in the axial direction.

[0119] According to this structure, the movement of the shaft member 60 in the axial direction relative to the central hole 50 is not restricted.

[0120] In this embodiment, the central hole 50 includes a first inlet 50a through which the shaft member 60 enters, and a second inlet 50b axially located further inward from the first inlet 50a and larger than the first inlet 50a. The second branch passage valve 22A includes a protrusion 62 that protrudes radially from the shaft member 60 and has a substantially identical outer shape to the first inlet 50a.

[0121] With this structure, when the protrusion 62 is positioned at the second inlet 50b via the first inlet 50a, the protrusion 62 remains within the second inlet 50b unless its outer shape matches the first inlet 50a. In other words, the protrusion 62 is easily inserted into the second inlet 50b and difficult to remove from it. Consequently, the first and second branch passage valves 21A, 22A are held in a position where they are difficult to remove. This facilitates assembly and disassembly of the check valve 20 relative to the valve body 30, improving maintainability.

[0122] 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.

[0123] For example, in the above-mentioned 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.

[0124] In the above embodiment, the third check valve 20C is described as being different from the first check valve 20A, but the present invention is not limited to this. For example, the third check valve 20C may be the same as the first check valve 20A. For example, the hydraulic control valve may include three common check valves. For example, the hydraulic control valve may include three different check valves.

[0125] In the above embodiment, the example in which the protrusion 62 extends uniformly in the axial direction is cited for explanation, but the present invention is not limited to this. Figure 12As shown in FIG. 1 , the protrusion 162 may also have a tapered shape. The protrusion 162 has an inclined surface that gradually becomes smaller inward in the radial direction as it goes toward the side opposite to the second inclined surface 61. Figure 12 In the embodiment, the same structures as those in the above embodiment are marked with the same figure marks and their detailed descriptions are omitted.

[0126] This structure makes it easier to position the protrusion 162 at the second inlet 50b via the first inlet 50a, compared to a case where the protrusion extends uniformly in the axial direction. This facilitates installation of the first and second branch passage valves 21A, 22A, and makes removal of the first and second branch passage valves 21A, 22A difficult. This makes assembly and disassembly of the check valve 20 relative to the valve body 30 easier, further improving maintainability.

[0127] [Second embodiment]

[0128] Figure 13 It is a schematic diagram of the check valve of the second embodiment.

[0129] In the above embodiment, the central hole 50 is described as an example in which the central hole 50 is opened in the entire body 51 in the axial direction, but the present invention is not limited to this. Figure 13 As shown, the first branch passage valve 221A may also include a partition 257 that divides the central hole 50 into a first region 255 on one side in the axial direction and a second region 256 on the other side in the axial direction. The shaft member 60 is disposed in the second region 256. Figure 13 In the embodiment, the same structures as those in the above embodiment are marked with the same figure marks and their detailed descriptions are omitted.

[0130] The partition 257 is disposed between the second inlet 50b and the third inlet 50c. The partition 257 has an annular shape when viewed in the axial direction. The first region 255 is located on the side opposite to the second branch passage valve 22A across the partition 257 in the axial direction ( Figure 13 The second region 256 is located on the opposite side of the first region 255 across the partition 257 in the axial direction ( Figure 13 on the lower side of the ).

[0131] The first coil spring 24 and the second coil spring 25 are arranged at different positions in the axial direction. The first coil spring 24 is arranged between the partition 257 of the first branch passage valve 221A and the plug 18. The second coil spring 25 is arranged between the protrusion 62 of the second branch passage valve 22A and the partition 257 of the first branch passage valve 221A.

[0132] In this embodiment, the first branch passage valve 221A includes a partition 257 that partitions the central hole 50 into a first region 255 on one axial side and a second region 256 on the other axial side. The shaft member 60 is disposed in the second region 256 .

[0133] According to this structure, the movement of the shaft member 60 in the axial direction relative to the center hole 50 can be restricted by the spacer 257 .

[0134] In the above embodiment, the hydraulic system is described by taking as an example a hydraulic actuator driven by the working oil of a hydraulic pump, but the present 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 (pump fluid).

[0135] Furthermore, the components in the above-described embodiments may be replaced with well-known components without departing from the spirit of the present invention.

Claims

1. A fluid control valve, wherein: The fluid control valve has: a first check valve capable of allowing fluid to pass from the first pump passage to the bridge supply passage; a second check valve capable of allowing fluid to pass from the second pump passage to the bridge supply passage; as well as a third check valve capable of allowing fluid to flow from the third pump passage to the bridge supply passage; The first plug of the first check valve supports a portion of the third check valve. The second plug of the second check valve supports another portion of the third check valve.

2. The fluid control valve according to claim 1, wherein: The first pump passage includes a first branch passage capable of supplying fluid to the bridge-type supply passage and a second branch passage capable of supplying fluid to the bridge-type supply passage.

3. The fluid control valve according to claim 1, wherein: The second pump passage includes a third branch passage capable of supplying fluid to the bridge-type supply passage, and a fourth branch passage capable of supplying fluid to the bridge-type supply passage.

4. The fluid control valve according to claim 2, wherein: The first check valve includes a first branch passage valve that allows fluid to flow from the first branch passage to the bridge supply passage, and a second branch passage valve that allows fluid to flow from the second branch passage to the bridge supply passage.

5. The fluid control valve according to claim 3, wherein: The second check valve includes a third branch passage valve capable of allowing fluid to flow from the third branch passage to the bridge supply passage, and a fourth branch passage valve capable of allowing fluid to flow from the fourth branch passage to the bridge supply passage.

6. The fluid control valve according to claim 4, wherein: The first branch passage valve includes a main body having a central hole along an axis, and the first branch passage valve includes a first inclined surface provided on an outer periphery of the main body and obliquely intersecting with respect to the axis. The second branch passage valve includes a shaft member configured to be movable relative to the central hole in an axial direction parallel to the axis, and the second branch passage valve has a second inclined surface provided on the outer periphery of the shaft member and intersecting obliquely with respect to the axis.

7. A fluid control valve, wherein: The fluid control valve has: a first check valve capable of allowing fluid to pass from a first pump passage to a bridge-type supply passage, the first pump passage having a first branch passage capable of supplying fluid to the bridge-type supply passage and a second branch passage capable of supplying fluid to the bridge-type supply passage, the first check valve comprising a first branch passage valve capable of allowing fluid to pass from the first branch passage to the bridge-type supply passage, and a second branch passage valve capable of allowing fluid to pass from the second branch passage to the bridge-type supply passage, the first branch passage valve comprising a main body having a central hole along an axis, the first branch passage valve comprising a first inclined surface provided on an outer periphery of the main body and intersecting obliquely with respect to the axis, the second branch passage valve comprising a shaft member arranged to be movable in an axial direction parallel to the axis relative to the central hole, the second branch passage valve comprising a second inclined surface provided on an outer periphery of the shaft member and intersecting obliquely with respect to the axis; a second check valve capable of allowing fluid to pass from a second pump passage to the bridge supply passage, the second pump passage having a third branch passage capable of supplying fluid to the bridge supply passage and a fourth branch passage capable of supplying fluid to the bridge supply passage, the second check valve including a third branch passage valve capable of allowing fluid to pass from the third branch passage to the bridge supply passage and a fourth branch passage valve capable of allowing fluid to pass from the fourth branch passage to the bridge supply passage; as well as A third check valve is configured to allow fluid to flow from the third pump passage to the bridge supply passage. A portion of the third check valve is supported by the first plug of the first check valve, and another portion of the third check valve is supported by the second plug of the second check valve.

8. A fluid control valve, wherein: The fluid control valve has: a first check valve capable of allowing fluid to pass from a first pump passage to a bridge supply passage, the first pump passage having a first branch passage capable of supplying fluid to the bridge supply passage and a second branch passage capable of supplying fluid to the bridge supply passage, the first check valve including a first branch passage valve capable of allowing fluid to pass from the first branch passage to the bridge supply passage, and a second branch passage valve capable of allowing fluid to pass from the second branch passage to the bridge supply passage, the first branch passage valve including a main body having a central hole along an axis, the first branch passage valve including: a first inclined surface provided on an outer periphery of the main body and intersecting obliquely with respect to the axis; and a partition provided on an inner periphery of the main body and dividing the central hole into one side and another side in an axial direction parallel to the axis, the second branch passage valve including a shaft member arranged to be movable in the axial direction relative to the central hole, the second branch passage valve including a second inclined surface provided on an outer periphery of the shaft member and intersecting obliquely with respect to the axis; a second check valve capable of allowing fluid to pass from a second pump passage to the bridge supply passage, the second pump passage having a third branch passage capable of supplying fluid to the bridge supply passage and a fourth branch passage capable of supplying fluid to the bridge supply passage, the second check valve including a third branch passage valve capable of allowing fluid to pass from the third branch passage to the bridge supply passage and a fourth branch passage valve capable of allowing fluid to pass from the fourth branch passage to the bridge supply passage; as well as A third check valve is configured to allow fluid to flow from the third pump passage to the bridge supply passage. A portion of the third check valve is supported by the first plug of the first check valve, and another portion of the third check valve is supported by the second plug of the second check valve.

9. A fluid system, wherein: The fluid system has: A fluid control valve comprising: a first check valve capable of allowing fluid to flow from a first pump passage to a bridge supply passage; and a second check valve capable of allowing fluid to flow from a second pump passage to the bridge supply passage. and a third check valve capable of allowing fluid to pass from the third pump passage to the bridge supply passage; a fluid supply source that supplies fluid to the first pump passage, the second pump passage, and the third pump passage; as well as a driving body, which is driven by the fluid, The first plug of the first check valve supports a portion of the third check valve. The second plug of the second check valve supports another portion of the third check valve.

10. The fluid system according to claim 9, wherein: The fluid supply source is provided with a plurality of The plurality of fluid supply sources respectively include: a first pump that supplies fluid to the first pump passage; a second pump that supplies fluid to the second pump passage; and The third pump supplies fluid to the third pump passage.

11. The fluid system according to claim 9 or 10, wherein: The first pump passage includes a first branch passage and a second branch passage. The first branch passage is a parallel passage capable of supplying fluid to the bridge supply passage. The second branch passage is a series passage capable of supplying fluid to the bridge supply passage.

12. A construction machine, wherein: The construction machinery has: A fluid control valve comprising: a first check valve capable of allowing fluid to flow from a first pump passage to a bridge supply passage; and a second check valve capable of allowing fluid to flow from a second pump passage to the bridge supply passage. and a third check valve capable of allowing fluid to pass from the third pump passage to the bridge supply passage; a fluid supply source that supplies fluid to the first pump passage, the second pump passage, and the third pump passage; as well as a driving body, which is driven by the fluid, The first plug of the first check valve supports a portion of the third check valve. The second plug of the second check valve supports another portion of the third check valve.

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