Manufacturing method of resin-metal composite charge valve

Abstract

To provide a resin-metal composite charge valve which inhibits gas leakage while including a valve body containing a resin.SOLUTION: A charge valve 100 includes: a valve core 1 in which a male screw part 11s is provided on an outer peripheral surface; and a valve body 2 in which the valve core 1 is disposed. A manufacturing method of the charge valve 100 includes: an irregularities formation step in which irregularities are formed on an outer peripheral surface of a precursor which will serve as a first main part 21 of the valve body 2; a surface roughening step in which the outer peripheral surface of the precursor is roughened; an adhesive application step in which an adhesive 40 is applied to a roughened portion having the irregularities formed on the outer peripheral surface of the first main part 21, which is obtained by the irregularities formation step and the surface roughening step; a second main part formation step in which a second main part 22 is formed outside the first main part 21 by injection molding after the adhesive application step; and a valve core attachment step in which the valve core 1 is disposed within the first main part 21 and the male screw part 11s is threadedly engaged with a female screw part 21s to attach the valve core 1 to the first main part 21.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a charge valve to be attached to an air conditioning pipe for an automobile. [Background technology]

[0002] Patent Document 1 describes technology related to a charge valve. The charge valve described in Patent Document 1 has a valve core disposed inside a valve body. The valve core is made of a soft metal such as brass. The valve body is made of an aluminum alloy or the like.

[0003] To further reduce the weight of automobiles, the use of resin for automotive air conditioning piping is being considered. When using resin for air conditioning piping, if the charge valve attached to the piping is also made of resin, simply making the valve body out of resin poses the following problems: Creep may occur in the resin female thread of the valve body to which the valve core is fixed, causing the valve core to loosen due to vibration, etc. If the valve core loosens, gas leakage may occur from the loosened part. Creep refers to the phenomenon in which the amount of deformation of a material increases over time when a static load is continuously applied to the material.

[0004] Therefore, in Patent Document 2, the inventors of the present application have proposed a charge valve that uses a resin for the valve body while preventing the valve core from loosening due to creep and thereby suppressing gas leakage. Specifically, they have proposed a resin-metal composite charge valve that includes a valve core having a male thread on its outer circumferential surface and a valve body in which the valve core is disposed, the valve body including: a first valve body made of resin having a cylindrical housing portion; a second cylindrical metal valve body housed in the housing portion, the second valve body having a female thread on its inner circumferential surface that screws onto the male thread portion; and a third cylindrical resin valve body whose base end is housed in the housing portion after the second valve body is housed in the housing portion, wherein a sealant is disposed between the outer circumferential surface of the second valve body and the inner circumferential surface of the housing portion (e.g., claim 1 of Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 09-119753 [Patent Document 2] Japanese Patent Publication No. 2022-188522 Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to propose a charge valve other than the charge valve described in Patent Document 2 as an automotive part that can provide the same effects as those described above.

[0007] The present invention aims to provide a method for manufacturing a resin-metal composite charge valve that has a valve body made of resin and can suppress gas leakage. [Means for solving the problem]

[0008] The manufacturing method of the resin-metal composite charge valve disclosed in this specification is a manufacturing method of a charge valve comprising a valve core having a male thread portion on its outer peripheral surface and a valve body in which the valve core is arranged, wherein the valve body has a first body portion made of metal having a female thread portion on its inner peripheral surface that screws into the male thread portion, and a second body portion made of resin in which the first body portion is arranged, and the manufacturing method includes the following steps: an unevenness forming step of forming unevenness on the outer peripheral surface of a precursor that will become the first body portion; a roughening step of roughening the outer peripheral surface of the precursor; an adhesive application step of applying an adhesive to the uneven and roughened portions of the outer peripheral surface of the first body portion that has been manufactured by the unevenness forming step and the roughening step; a second body portion forming step of forming the second body portion on the outside of the first body portion by injection molding after the adhesive application step; and a valve core attachment step of attaching the valve core to the first body portion by placing the valve core inside the first body portion and screwing the male thread portion into the female thread portion. [Effects of the Invention]

[0009] According to the above method, it is possible to manufacture a charge valve that has a valve body made of resin and is capable of suppressing gas leakage. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a partially cutaway cross-sectional view of the charge valve according to the first embodiment. [Figure 2] 2 is a partially enlarged view of the charge valve shown in FIG. 1 (an enlarged view of II shown in FIG. 1). [Figure 3] 3A to 3C are diagrams sequentially showing a method for manufacturing the charge valve according to the first embodiment (a step of forming recesses and projections). [Figure 4] 2A to 2C are diagrams sequentially showing a method for manufacturing a charge valve according to the first embodiment (surface roughening step and adhesive application step). [Figure 5] 5A to 5C are views sequentially showing a method for manufacturing the charge valve according to the first embodiment (a second body portion forming step). [Figure 6]3A to 3C are views sequentially showing a method for manufacturing the charge valve according to the first embodiment (a second body portion forming step, a valve core attaching step). [Figure 7] FIG. 10 is a partially cutaway cross-sectional view of a charge valve according to a second embodiment. [Figure 8] 8 is a partially enlarged view of the charge valve shown in FIG. 7 (an enlarged view of VIII shown in FIG. 1). [Figure 9] 10A to 10C are diagrams sequentially showing a method for manufacturing a charge valve according to a second embodiment (a concavo-convex forming step, a surface roughening step, and an adhesive application step). [Figure 10] 10A to 10C are views sequentially showing a method for manufacturing a charge valve according to a second embodiment (a second main body portion forming step). [Figure 11] 10A to 10C are views sequentially showing a method for manufacturing a charge valve according to a second embodiment (a second body portion forming step, a valve core attaching step). DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] 1 shows an example of a charge valve 100. The charge valve 100 is attached to, for example, a piping for an air conditioner in a vehicle.

[0012] As shown in FIG. 1, the charge valve 100 comprises a valve core 1, a valve body 2, and a cap 3. The valve core 1 is disposed inside the valve body 2. The cap 3 is attached to the upper end of the valve body 2. The cap 3 protects the valve core 1. In this embodiment, in the axial direction of the valve core 1, etc., the side of the cap 3 is referred to as the "upper side," and the side opposite the cap 3 is referred to as the "lower side."

[0013] Figure 2 shows an enlarged view of area II enclosed by the dashed line in Figure 1. As shown in Figure 2, the valve core 1 comprises a cylindrical valve core body 11, a rod-shaped valve member 12, and a coil spring 13. The valve core body 11 and the valve member 12 are made of metal, such as brass. An annular recess 11a is formed on the inner circumferential surface of the lower axial end of the valve core body 11. This recess 11a serves as the valve seat. Figure 2 shows an annular valve element 14 fitted into the recess 11a.

[0014] The coil spring 13 is inserted into the valve member 12. The coil spring 13 is mounted on the valve member 12 in a compressed state between the spring receiving portion 12a at the upper end of the valve member 12 and the end face of the valve core body 11. The biasing force of the coil spring 13 causes the valve element 14 to fit into the recess 11a. As shown in FIG. 2, when the valve element 14 is fitted into the recess 11a, the space above the valve core body 11 is not connected to the space below it (= the valve is closed). When the spring receiving portion 12a is pressed downward, the valve element 14 separates from the recess 11a, and the space above the valve core body 11 is connected to the space below it (= the valve is open). This allows gas (refrigerant gas) to flow into the space below the valve core body 11 (gas charge).

[0015] As shown in Figure 2, an annular groove 11g is formed on the outer peripheral surface of the valve core body 11. An annular O-ring 10 is disposed in the groove 11g. The O-ring 10 functions as a seal. A male thread 11s is formed on the outer peripheral surface of the valve core body 11 below the groove 11g.

[0016] As shown in FIG. 1, the valve body 2 on the outside of the valve core 1 has a first body portion 21 and a second body portion 22. The second body portion 22 is disposed outside the first body portion 21. The first body portion 21 is made of metal, such as an aluminum alloy. The second body portion 22 is made of resin, such as PA66, PA612, or PA9T.

[0017] The first main body portion 21 is cylindrical. As shown in Fig. 2, a female thread portion 21s is provided on the inner circumferential surface of the first main body portion 21. The female thread portion 21s is screwed onto the male thread portion 11s of the valve core 1.

[0018] An annular groove portion 21g is formed on the outer peripheral surface of the first main body portion 21. Groove portion 21g forms unevenness in the axial direction on the outer peripheral surface of the first main body portion 21. In the axial direction of the first main body portion 21, groove portion 21g is located below the female thread portion 21s.

[0019] The outer peripheral surface of the first main body portion 21 has a roughened portion to which an adhesive 40, which will be described later, is applied.

[0020] The degree of roughening is not particularly limited. The unevenness caused by the roughening has a smaller arithmetic mean roughness Ra and a smaller surface roughness (maximum height) Rz than the unevenness caused by the grooves 21g.

[0021] As shown in FIG. 1, the second body portion 22 on the outside of the first body portion 21 has a housing portion 22A and a pipe portion 22B. The housing portion 22A is cylindrical. The first body portion 21 is disposed inside the housing portion 22A. A through hole 22b is formed in the pipe portion 22B. The through hole 22b penetrates the housing portion 22A in a direction perpendicular to the axial direction. The through hole 22b communicates with the space below the valve core 1.

[0022] The inner circumferential surface of the accommodation portion 22A faces the outer circumferential surface of the first main body portion 21. An annular protrusion 22A1 is formed on the inner circumferential surface of the accommodation portion 22A, as shown in Fig. 2. The protrusion 22A1 is fitted into the groove 21g of the first main body portion 21.

[0023] The adhesive 40 is present between the accommodation portion 22A and the first main body portion 21. The adhesive 40 is present mainly in the roughened portion of the outer peripheral surface of the first main body portion 21. The adhesive 40 is present in the roughened portion of the outer peripheral surface of the first main body portion 21 where the unevenness caused by the groove portion 21g is formed. The adhesive 40 is also present on the wall surface defining the groove portion 21g. The adhesive 40 is also present between the wall surface defining the groove portion 21g and the protrusion 22A1 fitted into the groove portion 21g. The adhesive 40 is also present on the protrusions of the unevenness formed by the groove portion 21g. In other words, the adhesive 40 is also present on the upper and lower portions of the groove portion 21g on the outer peripheral surface of the first main body portion 21. The adhesive 40 penetrates into the minute depressions caused by the roughening and fills the depressions.

[0024] The material and type of adhesive 40 are not particularly limited. It is preferable to use an adhesive 40 that can bond metals and resins. For example, an adhesive containing a resin may be used. An adhesive containing a thermosetting resin may be used as the resin. The thermosetting resin is not particularly limited as long as it is a resin that hardens when heated. An adhesive containing a thermosetting resin may be, for example, an adhesive containing an epoxy resin. The epoxy resin is not particularly limited as long as it has an epoxy group in the molecule. Examples of epoxy resins include, but are not limited to, bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin. These may be used alone or in combination of two or more. The adhesive may further contain components other than those mentioned above, such as a curing accelerator.

[0025] Next, a method for manufacturing the charge valve 100 shown in Figures 1 and 2 will be described with reference to Figures 3 to 6. Here, an example will be described in which an adhesive containing a thermosetting resin is used as the adhesive 40 shown in Figure 2.

[0026] The left diagram of FIG. 3 shows a metal precursor P21. The precursor P21 will become the first main body portion 21 of the valve body 2 shown in FIG. 1. As shown in the left diagram of FIG. 3, the precursor P21 is cylindrical. A female thread portion 21s is formed on the inner circumferential surface of the precursor P21. The lower part of the precursor P21 is cylindrical with a constant outer diameter.

[0027] As shown in the right diagram of Fig. 3, an annular groove 21g is formed on the outer peripheral surface of the lower part of the precursor P21. The groove 21g forms irregularities on the outer peripheral surface of the lower part of the precursor P21 (irregularity forming step). The method for forming the groove 21g is not particularly limited. For example, the groove 21g may be formed by cutting or the like.

[0028] Next, as shown in the left diagram of FIG. 4, the outer peripheral surface of the lower part of the precursor P21 is roughened (roughening step). On the outer peripheral surface of the precursor P21, the groove portion 21g and the portions above and below the groove portion 21g are roughened over the entire circumferential direction. In other words, the irregularities formed on the lower part of the precursor P21 are roughened over the entire circumferential direction. The wall surfaces defining the groove portion 21g are also roughened. The roughening method is not particularly limited. For example, the roughening may be performed by an edging treatment using an acid, or by a blasting treatment. By roughening, irregularities are formed that have a smaller arithmetic mean roughness Ra and a smaller surface roughness (maximum height) Rz than the irregularities caused by the groove portion 21g.

[0029] The first main body portion 21 is obtained by the above-described unevenness forming step and surface roughening step.

[0030] After the unevenness forming step and the roughening step, adhesive 40 is applied to the outer peripheral surface of the lower part of first main body portion 21 (adhesive application step), as shown in the right diagram of FIG. 4. Here, unevenness is formed on the outer peripheral surface of the lower part of first main body portion 21, and adhesive 40 is applied to the roughened part. Adhesive 40 is also applied to the part of the outer peripheral surface of the lower part of first main body portion 21 that is only roughened and does not have groove portion 21g formed therein. Adhesive 40 is also applied to the surface that defines groove portion 21g. Groove portion 21g is not filled with adhesive 40. Adhesive 40 is filled in the depressions of the unevenness caused by the roughening.

[0031] After applying the adhesive 40, the adhesive 40 is heated to semi-harden the thermosetting resin contained in the adhesive 40 (adhesive heating step). A semi-hardened thermosetting resin is a state in which the thermosetting resin is not completely hardened. In a semi-hardened state, the adhesive 40 does not have enough fluidity to flow on the outer peripheral surface of the first main body portion 21, but it still has flexibility. When the thermosetting resin is in a semi-hardened state, the adhesive 40 has adhesive properties.

[0032] There are no particular limitations on the heating method and heating conditions for the adhesive 40. For example, the first body portion 21 may be placed in a heating chamber, or a heater may be brought close to the first body portion 21. Furthermore, the adhesive 40 may be brought into a semi-cured state by heating the first body portion 21 at a temperature lower than the curing temperature and for a time shorter than the curing time, taking into consideration the curing conditions (curing temperature, curing time, etc.) of the thermosetting resin contained in the adhesive 40.

[0033] Next, the second main body portion 22 is fabricated by the following method. The first body portion 21 with the adhesive 40 in a semi-cured state is placed in a mold M1 as shown in the left diagram of FIG. 5. The mold M1 has a cavity with the outer shape of the valve body 2 shown in FIG. 1. As shown in the right diagram of FIG. 5, the mold M1 is filled with molten resin R1. The heat of the molten resin R1 completely cures the semi-cured adhesive 40. Thereafter, the mold M1 is heated, pressurized, and pressure-maintained as necessary. The resin R1 is then cooled to solidify. The cooling method is not particularly limited. For example, the resin R1 may be cooled by air cooling. As a result, the second body portion 22 is formed as shown in the left diagram of FIG. 6. The first body portion 21 and the second body portion 22 are bonded together by the adhesive 40. The first body portion 21 and the second body portion 22 are removed from the mold M1. As a result of the above, the valve body 2 having the first body portion 21 and the second body portion 22 is obtained.

[0034] Next, as shown in the right diagram of Figure 6, the valve core 1 is placed inside the first body portion 21, and the male thread portion 11s of the valve core 1 is screwed into the female thread portion 21s of the first body portion 21. In this way, the valve core 1 is attached to the first body portion 21 (valve core attaching process).

[0035] The charge valve manufactured by the above method provides the following effects.

[0036] As shown in Figures 1 and 2, the charge valve 100 has the second body portion 22 of the valve body 2 made of resin, and therefore is lighter than a conventional charge valve made entirely of a metal valve body. Furthermore, since the female thread portion 21s into which the male thread portion 11s of the valve core 1 is threaded is made of metal, creep is suppressed in the threaded portion between the two, and loosening of the valve core 1 due to creep does not occur.

[0037] Furthermore, as shown in Figures 1 and 2, the presence of adhesive 40 between the metal first body portion 21 and the resin second body portion 22 prevents a gap from occurring between the first body portion 21 and the second body portion 22 even if the resin second body portion 22 expands due to heating or the like.

[0038] 4, adhesive 40 is applied to the portion of the outer peripheral surface of first main body portion 21 where unevenness is formed by groove portion 21g. Furthermore, adhesive 40 is applied to the roughened portion of the outer peripheral surface of first main body portion 21. This increases the area where adhesive 40 is applied.

[0039] 5, the adhesive 40 is pressed toward the first main body portion 21 when filling the resin R1, when pressurizing, and when holding the pressure. This increases the adhesion between the first main body portion 21 and the adhesive 40. The resin R1 is pressed toward the adhesive 40 when filling the resin R1, when pressurizing, and when holding the pressure. This causes the resin R1 and the adhesive 40 to bond together and increases the adhesion between them. When the resin R1 is solidified in this state, the adhesion between the second main body portion 22 and the adhesive 40, as shown in the left diagram of FIG. 6, increases.

[0040] As a result of the above, a charge valve 100 is obtained that is equipped with a valve body 2 made of resin and is capable of suppressing gas leakage.

[0041] Furthermore, when the adhesive 40 contains a thermosetting resin, as shown in the right diagram of FIG. 4 , after the adhesive 40 is applied to the first body portion 21, the thermosetting resin contained in the adhesive 40 is semi-cured before injection molding. This prevents the adhesive 40 from shifting from the first body portion 21 even when pressure is applied to the adhesive 40 during injection molding in the second body portion formation process shown in FIGS. 5 and 6 . Therefore, gaps are less likely to form between the first body portion 21 and the adhesive 40. Furthermore, because the thermosetting resin contained in the adhesive 40 is semi-cured, the adhesive 40 has adhesive properties. When the resin R1 that will become the second body portion 22 is filled in, the resin R1 adheres to the adhesive 40. Since the resin R1 is pressurized while adhered to the adhesive 40, gaps are less likely to form between the resin R1 and the adhesive 40. Furthermore, the heat of the resin R1 completely cures the thermosetting resin during fabrication of the second body portion 22. This improves adhesion between the second body portion 22 and the adhesive 40. As a result, gas leakage from between the first main body portion 21 and the second main body portion 22 can be further suppressed.

[0042] 1 and 2, an annular groove 21g is formed on the outer peripheral surface of the first main body portion 21, and the protrusion 22A1 is fitted into the groove 21g. This can be achieved by the second main body portion forming step shown in FIGS. With the above configuration, one of the first main body portion 21 and the second main body portion 22 will not fall off in the axial direction.

[0043] Second Embodiment Next, a method for manufacturing a charge valve according to a second embodiment will be described below with reference to Figures 7 to 11. The main differences between the second embodiment and the first embodiment are the configuration of the valve body and the method for forming the valve body. Note that descriptions of configurations and processes similar to those of the first embodiment will be omitted where appropriate. In this embodiment as well, in the axial direction of the valve core 1, etc., the side of the cap 3 will be referred to as the "upper side," and the side opposite the cap 3 will be referred to as the "lower side."

[0044] The charge valve 200 shown in Fig. 7 is attached to, for example, the piping for an air conditioner in a vehicle. As shown in Fig. 7, the charge valve 200 includes a valve core 1, a valve body 202, and a cap 3. The valve core 1 is disposed inside the valve body 202.

[0045] The valve body 202 has a first body portion 221 and a second body portion 222. The valve core 1 is disposed inside the first body portion 221. The first body portion 221 is disposed inside the second body portion 222.

[0046] The first main body 221 is made of metal. For example, the first main body 221 is made of an aluminum alloy. The second main body 222 is made of resin. For example, the second main body 222 is made of PA66, PA612, PA9T, or the like.

[0047] The first main body portion 221 is cylindrical. As shown in Fig. 8, a female screw portion 221s is provided on the inner circumferential surface of the first main body portion 221. The female screw portion 221s is screwed onto the male screw portion 11s of the valve core 1.

[0048] A plurality of grooves 221g are formed on the outer peripheral surface of the first main body portion 221 by knurling or the like. The grooves 221g are continuous in a direction inclined with respect to the axial and circumferential directions of the first main body portion 221. The plurality of grooves 221g form a plurality of protrusions in a grid pattern on the outer peripheral surface of the first main body portion 221. The grooves 221g form unevenness on the outer peripheral surface of the first main body portion 221.

[0049] The outer peripheral surface of the first main body portion 221 has a roughened portion to which adhesive 240, which will be described later, is applied.

[0050] The degree of roughening is not particularly limited. The unevenness caused by the roughening has a smaller arithmetic mean roughness Ra and a smaller surface roughness (maximum height) Rz than the unevenness caused by the grooves 221g.

[0051] As shown in FIG. 7, the second main body portion 222 on the outside of the first main body portion 221 has a housing portion 222A and a pipe portion 222B. The housing portion 222A is cylindrical. The first main body portion 221 is disposed inside the housing portion 222A. A through hole 222b is formed in the pipe portion 222B. The through hole 222b penetrates the housing portion 222A in a direction perpendicular to the axial direction. The through hole 222b communicates with the space below the valve core 1.

[0052] 8, a groove 250g into which the first main body portion 221 fits is formed on the inner circumferential surface of the accommodation portion 222A. The groove 250g is annular. When the first main body portion 221 is fitted into the groove 250g, the outer circumferential surface and both axial end faces of the first main body portion 221 contact the wall surfaces that define the groove 250g.

[0053] Adhesive 240 is present between the outer peripheral surface of first main body portion 221 and storage portion 222A. Adhesive 240 is present mainly in the roughened portions of the outer peripheral surface of first main body portion 221. Adhesive 240 is present in the roughened portions of the outer peripheral surface of first main body portion 221 where irregularities are formed by groove portions 221g. Adhesive 240 penetrates into minute depressions caused by groove portions 221g and the roughened surface, and fills these minute depressions. Adhesive 240 is also present on the protrusions of the irregularities caused by groove portions 221g.

[0054] There are no particular limitations on the material and type of adhesive 240. The adhesive 240 is similar to the adhesive 40 described in the first embodiment.

[0055] Next, a method for manufacturing the charge valve 200 shown in Figures 7 and 8 will be described with reference to Figures 9 to 12. Here, an example will be described in which an adhesive containing a thermosetting resin is used as the adhesive 240 shown in Figure 8.

[0056] FIG. 9 shows the steps for producing the first main body portion 221 of the valve body 202 shown in FIG. 7 in sequence. The leftmost drawing in FIG. 9 shows a metal precursor P221. The precursor P221 will become the first main body portion 221 shown in FIG. 7. The precursor P221 is cylindrical. A female thread portion 221s is formed on the inner circumferential surface of the precursor P221. The precursor P221 is cylindrical with a constant outer diameter.

[0057] By knurling the outer peripheral surface of the precursor P221, a plurality of grooves 221g are formed on the outer peripheral surface of the precursor P221. The grooves 221g form irregularities on the outer peripheral surface of the precursor P221 (irregularity forming step).

[0058] Next, the outer peripheral surface of the precursor P221 is roughened (roughening step). On the outer peripheral surface of the precursor P221, the knurled portion and the portions above and below the knurled portion are roughened in the entire circumferential direction. In other words, on the outer peripheral surface of the precursor P221, the irregularities and the portions above and below them are roughened. The wall surfaces defining the groove portions 221g are also roughened. The roughening method is not particularly limited. For example, the roughening may be performed by an edging treatment using an acid, or by a blasting treatment. By roughening the surface, unevenness is formed that has a smaller arithmetic mean roughness Ra and a smaller surface roughness (maximum height) Rz than unevenness produced by knurling.

[0059] The first main body portion 221 is obtained by the above-described unevenness forming step and surface roughening step.

[0060] After the unevenness forming step and the roughening step, adhesive 240 is applied to the outer peripheral surface of first main body portion 221 (adhesive application step), as shown in the rightmost drawing in FIG. 10. Adhesive 240 is applied to the portions of the outer peripheral surface of first main body portion 221 where unevenness is formed and which have been roughened. Here, adhesive 240 is also applied to the portions of the outer peripheral surface of first main body portion 221 where unevenness is not formed and which have only been roughened. Groove portion 221g is filled with adhesive 240. Adhesive 240 is filled in the depressions in the unevenness caused by the roughening.

[0061] After applying the adhesive 240, the adhesive 240 is heated to semi-cure the thermosetting resin contained in the adhesive 240 (adhesive heating step). The semi-cure state of the thermosetting resin is the same as that described in the first embodiment. The heating conditions for semi-cure the thermosetting resin are also the same as those in the first embodiment.

[0062] Next, the second main body portion 222 is fabricated by the following method. The first body portion 221 with the adhesive 240 in a semi-cured state is placed in a mold M201 as shown in the left diagram of FIG. 10. The mold M201 has a cavity with the outer shape of the valve body 202 shown in FIG. 7. As shown in the right diagram of FIG. 10, the mold M201 is filled with molten resin R201. The heat of the molten resin R201 completely cures the semi-cured adhesive 240. Thereafter, the mold M201 is heated, pressurized, and pressure-maintained as necessary. The resin R201 is then cooled to solidify. The cooling method is not particularly limited. For example, the resin R201 may be cooled by air cooling. As a result, the second body portion 222 is formed as shown in the left diagram of FIG. 11. The first body portion 221 and the second body portion 222 are bonded together with the adhesive 240. The first body portion 221 and the second body portion 222 are removed from the mold M201, and burrs and the like are removed as necessary. As a result of the above, the valve body 202 having the first body portion 221 and the second body portion 222 is obtained.

[0063] 11, the valve core 201 is placed inside the first main body portion 221, and the male thread portion 221s of the valve core 201 is screwed into the female thread portion 221s of the first main body portion 221. In this way, the valve core 201 is attached to the first main body portion 221 (valve core attaching step).

[0064] The charge valve manufactured by the above method provides the following effects similar to those of the first embodiment.

[0065] As shown in Figures 7 and 8, the charge valve 200 has a second body portion 222 of the valve body 202 made of resin, and therefore is lighter than a conventional charge valve made entirely of a metal valve body. Furthermore, since the female thread portion 221s into which the male thread portion 211s of the valve core 201 is threaded is made of metal, creep is suppressed from occurring in the threaded portion between the two, and loosening of the valve core 201 due to creep does not occur.

[0066] Furthermore, as shown in Figures 7 and 8, the presence of adhesive 240 between the metal first body portion 221 and the resin second body portion 222 prevents a gap from occurring between the first body portion 221 and the second body portion 222 even if the resin second body portion 222 shrinks due to cooling or the like.

[0067] 9, adhesive 240 is applied to the portion of the outer peripheral surface of first main body portion 221 where unevenness is formed by groove portion 221g. Furthermore, adhesive 240 is applied to the roughened portion of first main body portion 221. This further increases the area where adhesive 240 is applied.

[0068] 10, the adhesive 240 is pressed toward the first main body portion 221 when the resin R201 is filled, when pressurizing, and when the pressure is maintained. This increases the adhesion between the first main body portion 221 and the adhesive 240. Furthermore, the resin R201 is pressed toward the adhesive 240 when the resin R201 is filled, when pressurizing, and when the pressure is maintained. This causes the resin R201 and the adhesive 240 to bond together and increases the adhesion between them. When the resin R201 is solidified in this state, the adhesion between the second main body portion 222 and the adhesive 240 shown in the left diagram of FIG. 11 increases.

[0069] As a result of the above, a charge valve 200 is obtained that is equipped with a valve body 202 made of resin and is capable of suppressing gas leakage.

[0070] Furthermore, when the adhesive 240 contains a thermosetting resin, as shown in FIG. 9 , after the adhesive 240 is applied to the first body portion 221, the thermosetting resin contained in the adhesive 240 is semi-cured before injection molding. This prevents the adhesive 240 from shifting from the first body portion 221 even when pressure is applied to the adhesive 240 during injection molding in the second body portion formation step shown in FIGS. 10 and 11 . Therefore, gaps are less likely to form between the first body portion 221 and the adhesive 240. Furthermore, since the thermosetting resin contained in the adhesive 240 is semi-cured, the adhesive 240 has adhesive properties. When the resin R201 that will become the second body portion 222 is filled in, the resin R201 adheres to the adhesive 240. Since the resin R201 is pressurized while adhered to the adhesive 240, gaps are less likely to form between the resin R201 and the adhesive 240. Furthermore, the heat of the resin R201 completely cures the thermosetting resin when the second body portion 222 is fabricated. This increases the adhesion between the second main body portion 222 and the adhesive 240. As a result, gas leakage from between the first main body portion 221 and the second main body portion 222 can be further suppressed.

[0071] 8, the first main body portion 221 is configured to fit into the groove 250g of the second main body portion 222. This can be achieved by the second main body portion forming step shown in FIGS. With the above configuration, one of the first main body portion 221 and the second main body portion 222 is prevented from falling off in the axial direction.

[0072] 8, grooves 221g are formed by knurling on the outer peripheral surface of first main body portion 221. Grooves 221g are inclined in the axial and circumferential directions of first main body portion 221. Adhesive 240 enters grooves 221g, and grooves 221g are filled with adhesive 240. As a result, when the valve core 201 is screwed into the first body portion 221, the wall surfaces defining the groove portion 221g come into contact with the adhesive 240, thereby preventing the first body portion 221 from rotating. This further prevents gas leakage between the first body portion 221 and the second body portion 222. Furthermore, when an axial force is applied to the first body portion 221, the wall surfaces defining the groove portion 221g come into contact with the adhesive 240, thereby preventing the first body portion 221 from moving in the axial direction. This prevents the first body portion 221 from coming loose in the axial direction. [Example]

[0073] The present invention will be described in more detail below with reference to examples. However, the following examples do not limit the present invention, and all modifications within the scope of the present invention are included in the technical scope of the present invention.

[0074] In the charge valve manufacturing method described in the first embodiment, charge valves No. 1 to 4 were manufactured under the conditions shown in Table 1. In Nos. 1 to 3, one or both of the roughening process and adhesive application process were not performed. In No. 4, a method similar to the charge valve manufacturing method described in the first embodiment was carried out. In the adhesive application process of Nos. 3 and 4, an adhesive containing a thermosetting resin was used. The other conditions were the same as in the charge valve manufacturing method according to the first embodiment.

[0075] [Table 1]

[0076] [Airtightness (submersion) test] After submerging the charge valve, 3.53 MPa of gas was sealed in the charge valve for 5 minutes, and the presence or absence of gas leakage was confirmed. The results are shown in Table 1. In No. 1 and No. 2, gas leaked from between the first body portion 21 and the second body portion 22 shown in Figure 2, but in No. 3 and No. 4, gas did not leak.

[0077] [High temperature cyclic pressure test] The following test was conducted on No. 3 and No. 4, which showed no gas leakage in the airtightness (submersion) test. Simulating the harsh conditions inside a vehicle, the test oil was sealed inside the charge valve in an atmosphere of 140°C, and the charge valve was repeatedly pressurized from 0 MPa to 3.53 MPa. This pressurization was repeated 150,000 times. The results are shown in Table 1. As shown in Table 1, in No. 3, oil leaked from between the first body portion 21 and the second body portion 22 shown in Figure 2 after 150,000 pressurization cycles. On the other hand, in No. 4, no oil leaked even after 150,000 pressurization cycles.

[0078] The above test showed that gas leakage can be suppressed by performing the unevenness forming process, the surface roughening process, and the adhesive application process on the first body portion 21, and then performing the second body portion forming process. Note that the above test was performed using the method described in the first embodiment, but similar results were also obtained when unevenness was formed on the first body portion 21 by knurling, as described in the second embodiment. Furthermore, similar results were also obtained with the charge valve configuration shown in the second embodiment.

[0079] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present invention is defined not by the above description but by the claims, and includes all modifications within the meaning and scope of the claims.

[0080] For example, the order of the "irregularity forming step" for forming irregularities on the outer peripheral surface of the precursor that will become the first main body portion and the "roughening step" for roughening the outer peripheral surface of the precursor is not particularly limited, and either can be performed first. If the "irregularity forming step" is performed first, the wall surface that defines the irregularities is roughened in the subsequent "roughening step," and small irregularities are formed on the wall surface due to the roughening. As a result, the adhesive penetrates not only the irregularities formed in the "irregularity forming step" but also the small irregularities formed within the irregularities, thereby further improving the adhesion between the first main body portion and the adhesive. This can further suppress gas leakage.

[0081] Furthermore, in the first and second embodiments, the adhesive (40, 240) contains a thermosetting resin, but the adhesive (40, 240) does not have to contain a thermosetting resin. If the adhesive (40, 240) does not contain a thermosetting resin, the adhesive heating step for semi-curing the thermosetting resin after the adhesive application step and before the second body portion forming step may not be necessary.

[0082] In the first embodiment, as shown in FIG. 2, the unevenness is formed by forming an annular groove 21g on the outer peripheral surface of the first body portion 21. However, the method for forming the unevenness on the outer peripheral surface of the first body portion 21 is not limited to the above method. For example, the unevenness may be formed on the outer peripheral surface of the first body portion 21 by knurling the outer peripheral surface of the first body portion 21. In the second embodiment, as shown in FIG. 8, the unevenness is formed by knurling the outer peripheral surface of the first body portion 221. However, the method for forming the unevenness on the first body portion 221 is not limited to the above method. For example, the unevenness may be formed on the outer peripheral surface of the first body portion 221 by forming an annular groove (for example, "groove 21g" shown in FIG. 2) on the outer peripheral surface of the first body portion 221.

[0083] 2, in the first embodiment, the groove portion 21g of the first main body portion 21 is located below the female thread portion 21s in the axial direction of the first main body portion 21. However, the position of the groove portion 21g is not limited to the above. For example, the groove portion 21g may be located at a height that overlaps with at least a portion of the female thread portion 21s in the axial direction of the first main body portion 21, or may be located above the female thread portion 21s.

[0084] 2, the groove 21g of the first body portion 21 is annular, but the groove 21g may not be annular and may be formed partially. In this case, the protrusion of the second body portion 22 may fit into the partial groove. In this case, a rotation-preventing effect of the first body portion 21 can be obtained when the valve core 1 is screwed in.

[0085] Furthermore, the portions of the first main body portion (21, 221) to be roughened are not limited to the portions shown in Fig. 2 and Fig. 8. For example, only a portion of the portion of the outer peripheral surface of the first main body portion (21, 221) where projections and recesses are formed may be roughened. On the outer peripheral surface of the first main body portion (21, 221), a portion or all of the portion where projections and recesses are formed and a portion where projections and recesses are not formed may be roughened.

[0086] Furthermore, the portions of the first main body portion (21, 221) to which the adhesive (40, 240) is applied are not limited to the portions shown in FIGS. 2 and 8. For example, only a portion of the portion of the outer peripheral surface of the first main body portion (21, 221) where projections and recesses are formed and roughened may be roughened. Furthermore, the adhesive may be applied to a portion or all of the portion of the outer peripheral surface of the first main body portion (21, 221) where projections and recesses are formed and roughened, and to other portions. The other portions include, for example, portions where projections and recesses are formed but not roughened, portions that are roughened but not formed with projections and recesses, and portions where projections and recesses are not formed and not roughened.

[0087] Furthermore, portions other than the outer peripheral surface of the first main body portion (21, 221) may also be unevenly formed, roughened, and / or coated with adhesive. For example, the bottom surface of the first main body portion 21 shown in Fig. 1 may be unevenly formed, roughened, and / or coated with adhesive. The upper and lower surfaces of the first main body portion 221 shown in Fig. 7 may be unevenly formed, roughened, and / or coated with adhesive.

[0088] The configuration of the valve core 1 shown in Figures 1, 2, 7, and 8 is an example, and the configuration of the valve core is not limited to the configuration shown in these figures. [Explanation of symbols]

[0089] 1 valve core 11s male thread part 2, 202 valve body 3 Cap 21, 221 First body part 21g, 221g groove 21s, 221s female thread 22, 222 second main body part 22A, 222A housing 22B, 222B pipe section 40, 240 adhesive M1, M201 type P21, P221 precursor R1, R201 resin 100, 200 charge valve

Claims

1. A method for manufacturing a charge valve comprising: a valve core having a male thread portion on its outer circumferential surface; and a valve body in which the valve core is disposed, The valve body includes a first body portion made of metal and having an internal thread portion formed on an inner circumferential surface thereof, the internal thread portion being adapted to threadably engage with the external thread portion, and a second body portion made of resin and having the first body portion disposed therein, a concavo-convex forming step of forming concavo-convex on an outer peripheral surface of the precursor that will become the first main body portion; a roughening step of roughening the outer peripheral surface of the precursor; an adhesive application step of applying an adhesive to the portion of the outer peripheral surface of the first main body portion on which the irregularities are formed and which has been roughened after the first main body portion is fabricated by the irregularity forming step and the roughening step; a second body portion forming step of forming the second body portion on the outside of the first body portion by injection molding after the adhesive application step; a valve core mounting step of mounting the valve core to the first body portion by placing the valve core inside the first body portion and threading the male thread portion into the female thread portion; A method for manufacturing a resin-metal composite charge valve, comprising:

2. the adhesive comprises a thermosetting resin; and further comprising an adhesive heating step, which is performed after the adhesive application step and before the second body portion forming step, of heating the applied adhesive to semi-harden the thermosetting resin, In the second body forming step, the thermosetting resin is completely hardened.

2. The method for manufacturing a resin-metal composite charge valve according to claim 1.

3. In the unevenness forming step, the outer peripheral surface of the first main body portion is knurled to form unevenness on the outer peripheral surface of the first main body portion.

3. The method for manufacturing a resin-metal composite charge valve according to claim 1 or 2.

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