Valve body and method for casting the same

Abstract

To enable easy inspection of a curved flow channel.SOLUTION: A valve body 100 includes a spool hole 20 in which a spool 1 is accommodated, a flow channel 21 at least a part of which is curved and opposite ends 24a, 24b of which are connected to the spool hole 20, an inspection hole 22 openly formed on an outer surface 100a of the valve body 100 and connected to the flow channel 21, and a plug 23 sealing the inspection hole 22.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a valve body and a casting method thereof.

Background Art

[0002] Patent Document 1 discloses a valve body in which a spool hole into which a spool is slidably inserted and a tank passage communicating with the spool hole are formed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] In the valve body as described in Patent Document 1, when inspecting a curved flow path such as a tank passage after manufacturing, inspection is performed visually or using an endoscope through the spool hole, but there are dead ends in the flow path, and it may be difficult to inspect the entire flow path.

[0005] The present invention has been made in view of the above problems, and an object thereof is to easily inspect a curved flow path.

Means for Solving the Problems

[0006] The present invention includes a valve body accommodation hole for accommodating a valve body, a flow path that is at least partially curved and both ends of which are connected to the valve body accommodation hole, an inspection hole that is formed to open on the outer surface of the valve body and is connected to the flow path, and a plug for sealing the inspection hole. The flow path has a first flow path section and a second flow path section connected to the valve body housing hole and formed perpendicular to the valve body housing hole, a third flow path section connected to the first flow path section and the second flow path section and formed parallel to the valve body housing hole, a first curved section connected to the first flow path section and the third flow path section and formed in a curved manner, and a second curved section connected to the second flow path section and the third flow path section and formed in a curved manner, and has inspection holes, a first inspection hole connected to the first curved section and a second inspection hole connected to the second curved section. It is characterized by the above.

[0007] In this invention, since an inspection hole connected to the flow path is formed in the valve body, it is possible to easily inspect the curved flow path. Furthermore, since the first and second inspection holes eliminate blind spots within the flow path, the flow path can be easily inspected.

[0008] Furthermore, the present invention relates to a valve body comprising: a valve body housing hole in which a valve body is housed; a flow path that is curved in part and has both ends connected to the valve body housing hole; an inspection hole formed on the outer surface of the valve body and connected to the flow path; and a plug for sealing the inspection hole, wherein the flow path has a first flow path section and a second flow path section connected to the valve body housing hole and formed perpendicular to the valve body housing hole; and a third flow path section connected to the first flow path section and the second flow path section and formed parallel to the valve body housing hole, the inspection hole is connected to the third flow path section, and the first flow path section and the second flow path section can be inspected by inserting an endoscope into the valve body housing hole.

[0009] In this invention, since the valve body has an inspection hole connected to the flow path, it is possible to easily inspect curved flow paths.

[0010] Furthermore, the present invention relates to a method for casting a valve body, wherein the valve body is cast using a valve body housing hole core for forming a valve body housing hole formed in the valve body, a flow path core formed in the valve body, which is at least partially curved and has both ends connected to the valve body housing hole, and an inspection hole core formed on the outer surface of the valve body and connected to the flow path. The flow path has a first flow path section and a second flow path section connected to the valve body housing hole and formed perpendicular to the valve body housing hole, a third flow path section connected to the first flow path section and the second flow path section and formed parallel to the valve body housing hole, a first curved section connected to the first flow path section and the third flow path section and formed in a curved manner, and a second curved section connected to the second flow path section and the third flow path section and formed in a curved manner, and has an inspection hole, a first inspection hole connected to the first curved section and a second inspection hole connected to the second curved section, and has an inspection hole core, a first inspection hole core for forming the first inspection hole and a second inspection hole core for forming the second inspection hole. It is characterized by the following.

[0011] In this invention, since the valve body has an inspection hole connected to the flow path, it is possible to easily inspect the curved flow path after casting. Furthermore, since the flow channel core is supported by two cores, a first core and a second core, that are oriented in different directions from each other, the assembly strength of the flow channel core can be improved.

[0012] Furthermore, the present invention is characterized in that the core for the inspection hole is connected to the core for the flow path and is supported by a mold for forming the outer shape of the valve body.

[0013] In this invention, the core for the flow path is supported in the mold via the core for the inspection hole, thus preventing damage to the core for the flow path during casting. [Effects of the Invention]

[0016] According to the present invention, it is possible to easily inspect curved flow channels. [Brief explanation of the drawing]

[0017] [Figure 1] This is a cross-sectional view of a valve body and a spool valve according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of a valve body and spool valve according to a modified embodiment of the present invention. [Figure 3] This is a cross-sectional view of a mold used to manufacture a valve body. [Figure 4] It is a cross-sectional view of a valve body obtained by casting. [Figure 5] It is a cross-sectional view of the valve body after processing.

Mode for Carrying Out the Invention

[0018] Hereinafter, with reference to the drawings, a valve body 100 according to an embodiment of the present invention and a method for manufacturing the same will be described.

[0019] As shown in FIG. 1, the valve body 100 is the body of a spool valve 101. The spool valve 101 supplies and discharges hydraulic oil as a working fluid to and from an actuator (not shown) such as a hydraulic cylinder or a hydraulic motor, and controls the operation of the actuator. The valve body 100 is manufactured by casting using an aluminum alloy or an iron-based alloy as a material.

[0020] The spool valve 101 includes a spool 1 as a valve element slidably incorporated in the valve body 100, a first pilot chamber 2 and a drain chamber 3 provided facing each end of the spool 1, and a centering spring 4 as a biasing member that is housed in the first pilot chamber 2 and applies a spring force to one end of the spool 1. The spool valve 101 switches the communication with a passage provided downstream. The spool valve 101 includes first and second ports 5 and 6 respectively connected to first and second passages provided downstream, a third port 7 connected to a flow path 21 described later, and ports such as first and second pump ports 8 and 9 communicating with a pump as a hydraulic supply source. The drain chamber 3 is connected to a drain passage.

[0021] When no pilot pressure acts on the first pilot chamber 2, the spool 1 is held in the neutral position by the biasing force of the centering spring 4. In this state, the hydraulic oil discharged from the first pump port 8 is supplied to the first passage through the first port 5 via the third port 7, and the hydraulic oil discharged from the second pump port 9 is supplied to the second passage through the second port 6.

[0022] When pilot pressure is introduced into the first pilot chamber 2, the spool 1 moves against the spring force of the centering spring 4, the first pump port 8 and the second port 6 communicate with each other, and the communication between the third port 7 and the first port 5 is blocked. Also, the second pump port 9 and the first port 5 communicate with each other, and the communication between the second pump port 9 and the second port 6 is blocked.

[0023] The valve body 100 has a spool hole 20 as a valve body accommodation hole for accommodating the spool 1, a flow path 21 formed with at least a part thereof being curved and both end portions 24a, 24b thereof being connected to the spool hole 20, and an inspection hole 22 for inspection formed by opening to the outer surface 100a of the valve body 100 and connected to the flow path 21.

[0024] Both ends of the spool hole 20 are formed by opening to the outer surface 100a of the valve body 100. The spool hole 20 has a sliding hole 20a in which the spool 1 slides and each port 5-9 having a larger inner diameter than the sliding hole 20a.

[0025] In this embodiment, the flow path 21 is a high-pressure flow path formed in a U-shape in cross-section, with both ends 24a and 24b connected to the spool hole 20. Specifically, the flow path 21 includes a first flow path section 21a, whose end 24a is connected to the first pump port 8 of the spool hole 20 and which is formed perpendicular to the spool hole 20; a second flow path section 21b, whose end 24b is connected to the third port 7 of the spool hole 20 and which is formed perpendicular to the spool hole 20; a third flow path section 21c, which is connected to the first flow path section 21a and the second flow path section 21b and which is formed parallel to the spool hole 20; a first curved section 25a, which is connected to the first flow path section 21a and the third flow path section 21c and which is formed by curving; and a second curved section 25b, which is connected to the second flow path section 21b and the third flow path section 21c and which is formed by curving. Thus, the first channel section 21a is connected to one end of the third channel section 21c via the first curved section 25a, and the second channel section 21b is connected to the other end of the third channel section 21c via the second curved section 25b. The first to third channel sections 21a, 21b, and 21c are formed in a straight line, while the first curved section 25a and the second curved section 25b are formed with a smooth curve. Thus, the channel 21 has two curved sections 25a and 25b, and is formed with a curve in part. Note that the term "vertical" above includes not only perfectly vertical surfaces, but also surfaces that are not strictly vertical but are slightly inclined due to manufacturing errors, etc. Similarly, the term "parallel" above includes not only perfectly parallel surfaces, but also surfaces that are not strictly parallel but are slightly inclined due to manufacturing errors, etc.

[0026] The inspection hole 22 is a hole for inspecting the curved flow path 21 after the valve body 100 has been manufactured. In this embodiment, since the valve body 100 is manufactured by casting, the flow path 21 may be deformed due to deformation during casting of the flow path core 40 (see Figure 3) for forming the flow path 21, as will be described later, or casting burrs may be generated inside the flow path 21. In addition, chips generated by machining the casting after casting may remain inside the flow path 21. Such defects related to the flow path 21 can be inspected through the inspection hole 22 after the valve body 100 has been manufactured.

[0027] The inspection hole 22 includes a first inspection hole 22a connected to the first curved portion 25a and a second inspection hole 22b connected to the second curved portion 25b. Specifically, the first inspection hole 22a extends coaxially with the first flow path portion 21a, and the second inspection hole 22b extends coaxially with the third flow path portion 21c. Thus, in this embodiment, two inspection holes 22a and 22b are formed in the valve body 100. Female threads are formed on the inner circumferential surfaces of the first inspection hole 22a and the second inspection hole 22b, and plugs 23 are fastened to each of the female threads. In this way, the first inspection hole 22a and the second inspection hole 22b are sealed by the plugs 23.

[0028] The inspection of the flow path 21 will be explained in detail. When inspecting the flow path 21, if there is no inspection hole 22, it is not possible to directly inspect the inside of the flow path 21 by visual inspection. By inserting an endoscope through the opening of the spool hole 20 and moving it along the spool hole 20, it is possible to inspect the inside of the first flow path section 21a and the second flow path section 21b, but the third flow path section 21c is in a blind spot from the spool hole 20 and cannot be inspected. It is also conceivable to insert the endoscope from the spool hole 20 into the first flow path section 21a or the second flow path section 21b and guide it to the third flow path section 21c, but guiding the endoscope in this way is a difficult task. Thus, the flow path 21 has two curved sections 25a and 25b, is formed in a curved shape, and both ends 24a and 24b are connected to the spool hole 20, so the flow path 21 itself does not open to the outer surface 100a of the valve body 100, and therefore there are blind spots inside the flow path 21.

[0029] In contrast, in this embodiment, since a first inspection hole 22a and a second inspection hole 22b connected to the flow path 21 are formed, the flow path 21 can be easily inspected. Specifically, the first flow path section 21a can be directly inspected visually through the first inspection hole 22a, and the third flow path section 21c can be directly inspected visually through the second inspection hole 22b. Furthermore, an endoscope can be inserted into the first flow path section 21a through the first inspection hole 22a to inspect the inside of the first flow path section 21a, and an endoscope can be inserted into the third flow path section 21c through the second inspection hole 22b to inspect the inside of the third flow path section 21c. The second flow path section 21b can be inspected by inserting an endoscope into the third flow path section 21c through the second inspection hole 22b. In this way, by inspecting the flow path 21 using the first inspection hole 22a and the second inspection hole 22b, there are no blind spots within the flow path 21, making it easy to inspect the flow path 21.

[0030] Furthermore, a third inspection hole (not shown) may be provided as the inspection hole 22, which is connected to the second curved section 25b and extends coaxially with the second flow channel section 21b. This allows for direct visual inspection of the inside of the second flow channel section 21b through the third inspection hole, and also allows for the insertion of an endoscope into the second flow channel section 21b through the third inspection hole to inspect the inside of the second flow channel section 21b.

[0031] Alternatively, as shown in Figure 2, only the inspection hole 22 connected to the longitudinal center of the third flow channel 21c may be provided. In this case, the inside of the third flow channel 21c can be inspected by inserting an endoscope into the third flow channel 21c through the inspection hole 22, while the first flow channel 21a and the second flow channel 21b can be inspected by inserting an endoscope into the spool hole 20.

[0032] After the inspection of the flow path 21 is completed, the first inspection hole 22a and the second inspection hole 22b are sealed by plugs 23. In this way, the first inspection hole 22a and the second inspection hole 22b do not function as flow paths but are provided solely for inspection.

[0033] The first inspection hole 22a and the second inspection hole 22b can also be used as a supply port or discharge port for cleaning fluid when cleaning the inside of the valve body 100 after the valve body 100 has been manufactured.

[0034] Next, the casting method for the valve body 100 will be described with reference to Figures 3 to 5. Figure 3 is a cross-sectional view of the mold 102 for manufacturing the valve body 100, Figure 4 is a cross-sectional view of the valve body 100 obtained by casting, and Figure 5 is a cross-sectional view of the valve body 100 after processing.

[0035] In manufacturing the valve body 100 by casting, the cores shown in Figure 3, such as the spool hole core 30 for forming the spool hole 20, the flow path core 40 for forming the flow path 21, and the inspection hole core 50 for forming the inspection hole 22, are manufactured in advance. In Figure 3, the illustration of cores other than the spool hole core 30, the flow path core 40, and the inspection hole core 50 is omitted. Along with the manufacturing of the cores, the mold 60 for forming the outer shape of the valve body 100 is also manufactured in advance. Then, molten metal, which will be the raw material for the casting, is poured into the mold 102 in which the cores 30, 40, and 50 are assembled inside the mold 60.

[0036] Each core 30, 40, 50 and mold 60 are formed by a sand mold containing a resin binder. During the solidification process of the molten metal, the resin binder is discharged as a gas from the casting due to the heat of the molten metal. After the molten metal has solidified, the sand is removed from the casting. In this way, a casting of the valve body 100 shown in Figure 4 is obtained. By processing the casting, the valve body 100 shown in Figure 5 is obtained. Specifically, internal threads are formed in the first inspection hole 22a and the second inspection hole 22b, and annular grooves are formed on the inner circumferential surface of the spool hole 20 corresponding to each port 5 to 9.

[0037] Next, the cores 30, 40, 50 and the mold 60 that constitute the mold 102 will be described in detail.

[0038] As shown in Figure 3, the spool hole core 30 for forming the spool hole 20 has a sliding hole forming portion 31 corresponding to the sliding hole 20a in which the spool 1 slides, and a port forming portion 32 corresponding to each of the ports 5 to 9.

[0039] The channel core 40 for forming the channel 21 has a first channel forming portion 40a corresponding to the first channel portion 21a, a second channel forming portion 40b corresponding to the second channel portion 21b, a third channel forming portion 40c corresponding to the third channel portion 21c, a first curved portion 40d corresponding to the first curved portion 25a, and a second curved portion 40e corresponding to the second curved portion 25b. The channel core 40 is formed in a U-shape in cross-section, and its two ends, the first channel forming portion 40a and the second channel forming portion 40b, are connected to the spool hole core 30. Specifically, the channel core 40 is formed separately from the spool hole core 30 and is bonded to the spool hole core 30 with an adhesive.

[0040] The inspection hole core 50 includes a first inspection hole core 51 for forming the first inspection hole 22a and a second inspection hole core 52 for forming the second inspection hole 22b.

[0041] The first inspection hole core 51 and the second inspection hole core 52 are connected to the flow channel core 40 and supported by the mold 60. Specifically, the first inspection hole core 51 is connected to the first curved forming section 40d, extends coaxially with the first flow channel forming section 40a, and is supported by the mold 60. The second inspection hole core 52 is connected to the second curved forming section 40e, extends coaxially with the third flow channel forming section 40c, and is supported by the mold 60. Note that the first inspection hole core 51 and the second inspection hole core 52 are not limited to being directly supported by the mold 60, but may be indirectly supported via cores connected to the mold 60.

[0042] In this embodiment, the first inspection hole core 51 and the second inspection hole core 52 are formed integrally with the flow channel core 40. That is, the first inspection hole core 51 and the second inspection hole core 52 and the flow channel core 40 are manufactured as a single core. On the other hand, the first inspection hole core 51 and the second inspection hole core 52 are formed separately from the mold 60 and bonded to the mold 60 with an adhesive. Alternatively, the first inspection hole core 51 and the second inspection hole core 52 may be formed integrally with the mold 60, and the flow channel core 40 may be formed separately and bonded to the flow channel core 40 with an adhesive.

[0043] When molten metal is poured into the mold 102 constructed as described above, pressure from the molten metal acts on the flow channel core 40 as the molten metal flows into the mold 102. Furthermore, since the specific gravity of the flow channel core 40 is lower than that of the molten metal, and there is a large difference in the specific gravity of the two, a large buoyant force acts on the flow channel core 40 in the molten metal when the mold 102 is oriented as shown in Figure 3. This may cause the flow channel core 40 to deform or stress to be generated at the connection between the flow channel core 40 and the spool hole core 30, potentially causing damage to the connection. However, in this embodiment, the flow channel core 40 is supported by the mold 60 via the inspection hole core 50, thereby improving the assembly strength of the flow channel core 40 and preventing deformation of the flow channel core 40 and damage to the connection between the flow channel core 40 and the spool hole core 30. This prevents defects in the flow channel 21 formed by the flow channel core 40. In particular, in this embodiment, the inspection hole core 50 is connected to the first and second curved forming portions 40d and 40e of the flow channel core 40, and thus supports the flow channel core 40 in two directions, as indicated by the arrows in Figure 3. Furthermore, in this embodiment, the flow channel core 40 is supported by two first inspection hole cores 51 and second inspection hole cores 52 whose orientations are 90 degrees apart. Therefore, the assembly strength of the flow channel core 40 can be effectively improved.

[0044] Possible methods to improve the strength of the channel core 40 include adding structural materials such as wire during the manufacturing of the channel core 40, using a resin binder with high hardness for the channel core 40, or applying a thicker coating to the surface of the channel core 40. However, all of these methods are costly. In contrast, this embodiment uses a simple configuration in which the channel core 40 is supported by the inspection hole core 50, which allows for low-cost implementation.

[0045] As described above, before casting, the first inspection hole core 51 and the second inspection hole core 52 have the function of improving the alignment accuracy of the flow channel core 40 when assembling the flow channel core 40. Furthermore, during casting, the first inspection hole core 51 and the second inspection hole core 52 have the function of supporting the flow channel core 40 and improving the assembly strength of the flow channel core 40. Moreover, after casting, the first inspection hole 22a and the second inspection hole 22b formed by the first inspection hole core 51 and the second inspection hole core 52 do not function as flow channels, but function as a configuration for inspecting the flow channel 21.

[0046] According to the above embodiments, the following effects and advantages are achieved.

[0047] Since the valve body 100 has a first inspection hole 22a and a second inspection hole 22b connected to the flow path 21, the curved flow path 21 can be easily inspected through the first inspection hole 22a and the second inspection hole 22b. Furthermore, during casting, the core 51 for the first inspection hole and the core 52 for the second inspection hole, which form the first inspection hole 22a and the second inspection hole 22b, function as support members for the flow path core 40, thereby preventing deformation of the flow path core 40 and damage to the connection between the flow path core 40 and the spool hole core 30. This prevents defects in the flow path 21 formed by the flow path core 40. Therefore, the quality of the valve body 100 is improved.

[0048] Modifications of the above embodiment will be described below.

[0049] (1) In the above embodiment, the valve body 100 is the body of the spool valve 101. However, the valve body 100 is not limited to the body of the spool valve 101, and may be the body of another valve.

[0050] (2) In the above embodiment, the flow path 21 has three straight first to third flow path sections 21a, 21b, and 21c and two curved sections 25a and 25b, and is formed in a U-shaped cross-section with a part curved. However, the flow path 21 is not limited to this shape and may have one or more curved sections. Also, the flow path 21 may have no straight sections and be curved as a whole. In other words, the flow path 21 only needs to have a curved shape in at least a part. Also, in the above embodiment, the flow path 21 is a high-pressure flow path. However, the flow path 21 is not limited to a high-pressure flow path and may be a low-pressure flow path.

[0051] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0052] The valve body 100 includes a spool hole 20 (valve body housing hole) in which a spool 1 (valve body) is housed, a flow path 21 which is curved in part and has both ends 24a and 24b connected to the spool hole 20, an inspection hole 22 formed opening on the outer surface 100a of the valve body 100 and connected to the flow path 21, and a plug 23 that seals the inspection hole 22.

[0053] In this configuration, the valve body 100 has an inspection hole 22 connected to the flow path 21, making it easy to inspect the curved flow path 21.

[0054] Furthermore, the flow path 21 has a first flow path section 21a and a second flow path section 21b connected to the spool hole 20 (valve body housing hole) and formed perpendicular to the spool hole 20, a third flow path section 21c connected to the first flow path section 21a and the second flow path section 21b and formed parallel to the spool hole 20, a first curved section 25a connected to the first flow path section 21a and the third flow path section 21c and formed in a curved shape, and a second curved section 25b connected to the second flow path section 21b and the third flow path section 21c and formed in a curved shape, and the inspection hole 22 has a first inspection hole 22a connected to the first curved section 25a and a second inspection hole 22b connected to the second curved section 25b.

[0055] In this configuration, the first inspection hole 22a and the second inspection hole 22b eliminate any blind spots within the flow path 21, making it easy to inspect the flow path 21.

[0056] Furthermore, the valve body 100 is cast using a spool hole core 30 (valve body housing hole core) for forming a spool hole 20 (valve body housing hole) formed in the valve body 100, a flow path core 40 for forming a flow path 21 formed in the valve body 100, which is at least partially curved and has both ends 24a and 24b connected to the spool hole 20, and an inspection hole core 50 for forming an inspection hole 22 which is formed opening on the outer surface 100a of the valve body 100 and connected to the flow path 21.

[0057] In this configuration, the valve body 100 has an inspection hole 22 connected to the flow path 21, making it easy to inspect the curved flow path 21 after casting.

[0058] Furthermore, the inspection hole core 50 is connected to the flow channel core 40 and is supported by a mold 60 for forming the outer shape of the valve body 100.

[0059] In this configuration, the flow channel core 40 is supported by the mold 60 via the inspection hole core 50, thus preventing damage to the flow channel core 40 during casting.

[0060] Furthermore, the flow path 21 is connected to the spool hole 20 (valve body housing hole) and has a first flow path section 21a and a second flow path section 21b formed perpendicular to the valve body housing hole, a third flow path section 21c connected to the first flow path section 21a and the second flow path section 21b and formed parallel to the spool hole 20, a first curved section 25a connected to the first flow path section 21a and the third flow path section 21c and formed in a curved manner, and a second curved section 25b connected to the second flow path section 21b and the third flow path section 21c and formed in a curved manner. The inspection hole 22 has a first inspection hole 22a connected to the first curved section 25a and a second inspection hole 22b connected to the second curved section 25b. The inspection hole core 50 has a first inspection hole core 51 for forming the first inspection hole 22a and a second inspection hole core 52 for forming the second inspection hole 22b.

[0061] In this configuration, the flow channel core 40 is supported by two cores 51 and 52 for the first and second inspection holes, which are oriented in opposite directions to each other, thereby improving the assembly strength of the flow channel core 40.

[0062] Although embodiments of the present invention have been described above, these embodiments merely illustrate one example of how the present invention can be applied, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of symbols]

[0063] 100... Valve body, 100a... Outer surface of valve body, 101... Spool valve, 102... Mold, 1... Spool (valve body), 20... Spool hole (valve body housing hole), 21... Flow path, 21a... First flow path section, 21b... Second flow path section, 21c... Third flow path section, 22... Inspection hole, 22a... First inspection hole, 22b... Second inspection hole, 23... Plug, 25a... First curved section, 25b... Second curved section, 30... Core for spool hole (core for valve body housing hole), 40... Core for flow path, 50... Core for inspection hole, 51... Core for first inspection hole, 52... Core for second inspection hole, 60... Mold

Claims

1. It is a valve body, A valve housing hole in which the valve body is housed, A flow path that is curved in part and has both ends connected to the valve housing hole, An inspection hole is formed on the outer surface of the valve body and is connected to the flow path, The system comprises a plug for sealing the inspection hole, The aforementioned flow path is A first flow path section and a second flow path section are connected to the valve body housing hole and formed perpendicular to the valve body housing hole, A third flow path is connected to the first flow path and the second flow path and is formed parallel to the valve body housing hole, A first curved portion is connected to the first flow channel portion and the third flow channel portion and is formed in a curved shape, It has a second curved portion connected to the second flow channel portion and the third flow channel portion, and formed in a curved manner, As the inspection hole, A first inspection hole connected to the first curved portion, Having a second inspection hole connected to the second curved portion A valve body characterized by the following features.

2. A valve body, A valve housing hole in which the valve body is housed, A flow path that is curved in part and has both ends connected to the valve housing hole, An inspection hole is formed on the outer surface of the valve body and is connected to the flow path, The system comprises a plug for sealing the inspection hole, The aforementioned flow path is A first flow path section and a second flow path section are connected to the valve body housing hole and formed perpendicular to the valve body housing hole, It has a third flow path section connected to the first flow path section and the second flow path section, and formed parallel to the valve body housing hole, The inspection hole is connected to the third flow channel, The first and second flow channels can be inspected by inserting an endoscope into the valve housing hole. A valve body characterized by the following features.

3. A method for casting a valve body, The valve body is A valve body housing hole core for forming a valve body housing hole in the valve body, A flow channel core formed in the valve body, which is curved in part and has both ends connected to the valve body housing hole, Cast using an inspection hole core formed to open on the outer surface of the valve body and to form an inspection hole connected to the flow path, The aforementioned flow path is A first flow path section and a second flow path section are connected to the valve body housing hole and formed perpendicular to the valve body housing hole, A third flow path is connected to the first flow path and the second flow path and is formed parallel to the valve body housing hole, A first curved portion is connected to the first flow channel portion and the third flow channel portion and is formed in a curved shape, It has a second curved portion connected to the second flow channel portion and the third flow channel portion, and formed in a curved manner, As the inspection hole, A first inspection hole connected to the first curved portion, It has a second inspection hole connected to the second curved portion, As the core for the inspection hole, A core for forming the first inspection hole, Having a second inspection hole core for forming the second inspection hole A method for casting a valve body, characterized by the features described above.

4. A method for casting a valve body according to claim 3, A method for casting a valve body, characterized in that the core for the inspection hole is connected to the core for the flow path and is supported by a mold for forming the outer shape of the valve body.

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