Resin valve device and method for manufacturing the same

Abstract

To suppress dimensional change of a housing due to temperature difference or temperature change of a use environment, to suppress change in valve opening characteristic, in a resin valve device.SOLUTION: A resin valve device comprises: a housing 3 including a flow path 2, and formed into a cylindrical manner from a fiber-reinforced resin; a valve seat provided in the flow path 2; a valve body provided in the flow path 2 so as to be able to seat on the valve seat; a valve shaft on which the valve body is provided; and a drive part that drives the valve shaft. The resin housing 3 has a plurality of ribs 3e, 3f extending in an axial direction on its outer peripheral surface and protruding in a radial direction, and a gate mark 11 formed by injection molding of a molten resin is arranged on an end surface 3Aa of one end side 3A of the housing 3 in the axial direction X.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to a resin valve device in which a housing is made of resin and a manufacturing method thereof.

Background Art

[0002] Conventionally, as this type of technology, for example, an EGR valve described in Patent Document 1 below is known. This EGR valve is provided in the passage of EGR gas and is used to adjust the flow rate of EGR gas. This valve includes a housing including a flow path for EGR gas, a valve seat provided in the flow path, a valve body provided to be seated on the valve seat in the flow path, a valve shaft provided with the valve body, and a drive unit for driving the valve shaft, and the housing is made of a resin material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the housing is made of resin, between normal temperature and high temperature, since the dimensions of the housing change due to the linear expansion difference, the valve opening characteristics of the EGR valve may change significantly. For example, when the EGR valve is opened at normal temperature and when it is opened at high temperature, there is a difference in the driving amount of the drive unit for the same opening degree. That is, the valve opening characteristics of the EGR valve change. Further, since the housing is made of a resin material, when the valve seat is integrally resin-molded with the housing, it becomes difficult to ensure the roundness of the valve seat.

[0005] This disclosed technology has been made in view of the above circumstances, and its purpose is to provide a resin valve device and a method for manufacturing the same that can suppress changes in the dimensions of the housing due to temperature differences or temperature changes in the operating environment and suppress changes in the valve opening characteristics. [Means for solving the problem]

[0006] To achieve the above objective, the technology described in claim 1 is: Including entrances and exits A housing formed in a cylindrical shape from fiber-reinforced resin and including a flow path; a valve seat provided in the flow path; a valve body provided in the flow path so as to be seatable on the valve seat; a valve stem on which the valve body is provided; and a drive unit for driving the valve stem. 、 In a resin valve device equipped with the above, the housing has a plurality of ribs extending axially and projecting radially on its outer circumferential surface, The valve seat has a cylindrical end flange on one end in the axial direction, and the valve seat is integrally formed with the housing at one end of the housing, and on the end face of the end flange, Gate marks from injection molding of molten resin are present. The gate marks are located in the circumferential direction of the end face of one end flange, corresponding to the spaces between adjacent ribs. This is the purpose.

[0007] According to the configuration of the above technology, the housing has multiple ribs that extend axially and project radially on its outer circumferential surface, so the housing is structurally reinforced by the ribs. Also, one end of the housing in the axial direction One end flange Since gate marks are placed on the end face, during injection molding of the housing, the axial direction of the gate marks is located in the mold cavity. End face of one end flange The fiber-reinforced molten resin is injected from the gate. Therefore, the orientation of the fibers in the molten resin tends to align in the axial direction of the housing. Also, since the ribs extend in the axial direction of the housing, the fiber-reinforced molten resin flows more easily in that direction, and the orientation of the fibers tends to align more easily. Furthermore, since the valve seat is formed integrally with the housing at one end of the housing where the gate trace is located, the fiber-reinforced molten resin injected from the gate is easily filled into the position corresponding to the valve seat. In addition, since the gate trace is positioned in the circumferential direction of the end face of the flange at one end, corresponding to the space between adjacent ribs, the fiber-reinforced molten resin injected from the gate flows circumferentially around the cavity before flowing axially. .

[0012] To achieve the above objective, Claim 2 The technology described in the claim 1 In the manufacturing method for the resin valve device described, the housing is located in the cavity of the mold. One end flange The purpose is to be molded by molten resin containing fibers, which is injected from a gate positioned corresponding to the end face.

[0013] According to the above technology configuration, the housing is located in the cavity of the mold. One end flange It is formed by molten resin containing fibers injected from a gate positioned corresponding to the end face. Therefore, the orientation of the fibers in the molten resin is easily aligned in the axial direction of the housing. Also, since the ribs extend in the axial direction of the housing, the molten resin containing fibers flows easily in that direction, making it easier for the orientation of the fibers to be aligned. [Effects of the Invention]

[0014] According to the technology described in claim 1, it is possible to suppress changes in the dimensions of the housing due to temperature differences or temperature changes in the operating environment, and to suppress changes in the valve opening characteristics of the valve device. Furthermore, the roundness of the valve seat can be improved. In addition, molten resin can be sufficiently filled into the valve seat and the area where the valve seat is located, further improving the roundness of the valve seat and the area where the valve seat is located, as well as the fiber orientation in the rib.

[0017] Claim 2 According to the technology described, it is possible to manufacture a housing that exhibits minimal dimensional changes due to temperature differences or temperature changes in the operating environment. This housing contributes to suppressing changes in the valve opening characteristics of the valve device. [Brief explanation of the drawing]

[0018] [Figure 1] A cross-sectional view showing an EGR valve according to the first embodiment. [Figure 2] A perspective view relating to the first embodiment, showing the housing with the outlet of the flow path facing forward. [Figure 3] A perspective view relating to the first embodiment, showing the housing with the outlet of the flow path facing the rear. [Figure 4] A cross-sectional view schematically showing a part of the housing manufacturing process using a mold, relating to the first embodiment. [Figure 5] A pie chart showing the roundness of the valve seat after resin molding shrinkage, relating to the first embodiment. [Figure 6] A perspective view relating to the second embodiment, showing the housing, similar to Figure 3. [Figure 7] A pie chart showing the roundness of the valve seat after resin molding shrinkage, relating to the second embodiment. [Modes for carrying out the invention]

[0019] Hereinafter, several embodiments in which a resin valve device and its manufacturing method are embodied in an EGR valve will be described in detail with reference to the drawings.

[0020] <First Embodiment> First, the first embodiment will be described in detail with reference to FIGS. 1 to 4.

[0021] [Regarding the configuration of the EGR valve] FIG. 1 shows a cross-sectional view of the EGR valve 1 of this embodiment. As shown in FIG. 1, the EGR valve 1 has a poppet-type valve structure, and includes a housing 3 including a flow path 2 for EGR gas, an annular valve seat 4 provided in the flow path 2, a substantially umbrella-shaped valve body 5 provided to be seated on the valve seat 4 in the flow path 2, a valve shaft 6 to which the valve body 5 is fixed at one end, and a drive unit 7 for reciprocally driving the valve shaft 6 in the axial direction together with the valve body 5. The housing 3 is fastened to the drive unit 7 by a thermal caulking (not shown). The valve shaft 6 extending from the drive unit 7 is incorporated into the central hole 8 of the housing 3.

[0022] The flow path 2 includes an inlet 2a at one end and an outlet 2b at the other end. The drive unit 7 can be configured by, for example, a well-known DC motor or a step motor. The housing 3 is formed in a substantially cylindrical shape by a resin containing fibers. The valve seat 4 is formed integrally with the housing 3 by resin. The valve body 5 and the valve shaft 6 are formed of a metal material. The EGR valve 1 is adapted to adjust the EGR gas flow rate in the flow path 2 by moving the valve body 5 axially with respect to the valve seat 4 to change the opening degree between the valve body 5 and the valve seat 4. Here, a detailed description of the drive unit 7 will be omitted.

[0023] [Regarding the configuration of the housing] The configuration of housing 3 will now be described. Figures 2 and 3 show the housing 3 of this embodiment in a perspective view, inverted vertically compared to the housing 3 shown in Figure 1. Figure 2 shows the outlet 2b of the flow path 2 facing forward, and Figure 3 shows the outlet 2b facing backward. In Figures 2 and 3, the inlet 2a of the flow path 2 is visible at the upper end of housing 3. In this embodiment, the side of housing 3 where the inlet 2a is located is defined as one end 3A of housing 3, and the side opposite one end 3A is defined as the other end 3B.

[0024] In this embodiment, the housing 3 is substantially cylindrical and, externally, has a one-end flange 3a located at the upper end of Figures 2 and 3, a other-end flange 3b located at the lower end, and two intermediate flanges 3c and 3d located in the middle. The housing 3 has a plurality of ribs 3e and 3f extending axially and projecting radially on its outer circumferential surface. Specifically, three one-end ribs 3e extending axially are provided between the one-end flange 3a and the intermediate flange 3c. The one-end ribs 3e are provided at equal angular (90°) intervals at positions that do not interfere with the outlet 2b of the flow path 2. Also, four other-end ribs 3f extending axially are provided at equal angular (90°) intervals between the other-end flange 3b and the intermediate flange 3d. The arrangement of the one-end ribs 3e and the other-end ribs 3f coincides in the circumferential direction. The dashed lines shown as crosses in Figures 2 and 3 coincide with the arrangement direction of each rib 3e and 3f.

[0025] In this embodiment, as shown in Figures 2 and 3, a plurality (four) of gate marks 11 are arranged on the end face 3Aa of one end 3A of the housing 3 in the axial direction X, formed by injection molding of fiber-reinforced molten resin. In this embodiment, a valve seat 4 is arranged on the end face 3A of the housing 3 where the four gate marks 11 are located. That is, the valve seat 4 is formed integrally with the housing 3 on the end face 3A of the housing 3 where the four gate marks 11 are located. The four gate marks 11 are arranged in the circumferential direction of the end face 3Aa of the housing 3, corresponding to the space between adjacent end ribs 3e.

[0026] [Regarding the manufacturing method of EGR valves] The EGR valve 1 of this embodiment can be manufactured by separately manufacturing the drive unit 7 to which the valve stem 6 is assembled, the valve body 5, and the housing 3, fastening the drive unit 7 and the housing 3 together, and fixing the valve body 5 to the tip of the valve stem 6 at the inlet 2a of the housing 3.

[0027] Here, the housing 3 is manufactured by injection molding a resin material as follows. Figure 4 shows a schematic cross-sectional view of part of the housing manufacturing process using a mold 21. This mold 21 is configured to clamp and unclamp in the front-to-back direction of Figure 4. As shown in Figure 4, the mold 21 is used to injection mold the housing 3 with resin. As shown in Figure 4, a cavity 23 for molding the housing 3 is formed in the clamped mold 21. Cores 24, 25, and 26 for molding the flow channels 2 and the central hole 8 are placed inside this cavity 23. Each of the cores 24 to 26 is configured to be removed from the mold 21 in the direction of the arrow.

[0028] In Figure 4, the upper side of the cavity 23 corresponds to one end 3A of the housing 3, and the lower side corresponds to the other end 3B. Corresponding to the upper side of the cavity 23, the mold 21 is provided with multiple gates 27 for injecting molten resin into the cavity 23. In Figure 4, two gates 27 are shown, but there are a total of four gates 27. These gates 27 are positioned to correspond to one end of the cavity 23, that is, to the end face of the flange 3a of the housing 3. The housing 3 is then molded in the cavity 23 of the mold 21 by fiber-reinforced molten resin injected from the four gates 27, which are positioned to correspond to the end face 3Aa of one end 3A of the housing 3.

[0029] [Regarding the operation and effects of EGR valves and their manufacturing methods] As described above, the configuration of the EGR valve 1 in this embodiment means that the housing 3 has a plurality of ribs 3e, 3f that extend axially and protrude radially on its outer circumferential surface, so that the housing 3 is structurally reinforced by each of the ribs 3e, 3f. In addition, a plurality of gate marks 11 are arranged on the end face 3Aa of one end 3A of the housing 3 in the axial direction, so when the housing 3 is injection molded, the fiber-reinforced molten resin is injected into the cavity 23 of the mold 21 from the gate 27 at one end in the axial direction. Therefore, the orientation of the fibers in the molten resin is easily aligned in the axial direction X of the housing 3. Also, since the plurality of ribs 3e, 3f extend in the axial direction X of the housing 3, the fiber-reinforced molten resin flows easily in that direction, and the orientation of the fibers is easily aligned. For this reason, dimensional changes of the housing 3 due to temperature differences or temperature changes in the operating environment can be suppressed, and changes in the opening characteristics of the EGR valve 1 can be suppressed.

[0030] In this embodiment, the fiber orientation rate of the resin housing 3 was improved to "54%". This is an improvement over the fiber orientation rate of "41%" when the gate marks are located on the side of the housing rather than the end face. Here, when the operating environment of the housing changed from "20°C" to "130°C", the axial elongation of the housing due to the temperature difference was "0.02 mm" greater when the orientation rate was "41%" than when it was "54%". This corresponds to "0.4 steps" when converted to the number of opening steps of an EGR valve driven by a stepper motor.

[0031] The "orientation rate" mentioned above refers to the fact that each of the countless points set in the model under analysis has an XYZ component called the orientation tensor direction. The orientation tensor direction is the XYZ component of a given point. The sum of the XYZ components equals "1". In the explanation above, the average value of the Z component (flow direction) of all points is defined as the "orientation rate".

[0032] In this embodiment of the EGR valve 1 configuration, the valve seat 4 is integrally formed with the housing 3 at one end 3A where multiple gate marks 11 are located. Therefore, during the manufacturing of the housing 3, the fiber-reinforced molten resin injected from the gate 27 into the cavity 23 in the mold 21 is more likely to fill the position corresponding to the valve seat 4 with molten resin at a higher temperature. As a result, the roundness of the valve seat 4 can be improved.

[0033] According to the configuration of the EGR valve 1 in this embodiment, the multiple gate marks 11 are arranged in the circumferential direction of the end face 3Aa of one end side 3A of the housing 3, corresponding to the space between adjacent one-end ribs 3e. Therefore, when manufacturing the housing 3, the fiber-reinforced molten resin injected from the multiple gates 27 flows circumferentially around the cavity 23, as indicated by the arrows in Figure 3, before flowing axially. As a result, the valve seat 4 and the area where the valve seat 4 is located can be sufficiently filled with molten resin, further improving the roundness of the valve seat 4 and the area where the valve seat 4 is located, and the fiber orientation within each rib 3e, 3f.

[0034] Figure 5 shows the roundness of the valve seat 4 after resin molding shrinkage in this embodiment as a pie chart. As shown in Figure 5, the degree of shrinkage in this embodiment varies within the range of "13.15 to 13.165", but it can be seen that it is within a relatively narrow range.

[0035] According to the manufacturing method of the EGR valve 1 of this embodiment, the housing 3 is formed in the cavity 23 of the mold 21 by fiber-reinforced molten resin injected from a plurality of gates 27 that correspond to the end face 3Aa of one end 3A of the housing 3. Therefore, the orientation of the fibers in the molten resin is easily aligned in the axial direction X of the housing 3. In addition, since the plurality of ribs 3e, 3f extend in the axial direction X of the housing 3, the fiber-reinforced molten resin flows easily in that direction, and the orientation of the fibers is easily aligned. For this reason, it is possible to manufacture a housing 3 that undergoes little dimensional change due to temperature differences or temperature changes in the operating environment. This housing 3 contributes to suppressing changes in the opening characteristics of the EGR valve 1.

[0036] <Second Embodiment> Next, the second embodiment will be described in detail with reference to Figures 6 and 7. In the following description, components equivalent to those in the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted, with the focus being on the differences.

[0037] [Regarding the configuration of the EGR valve] This embodiment differs from the first embodiment in terms of the configuration of the housing 3, specifically in the arrangement of the multiple gate marks 11 on the end face 3Aa of one end side 3A of the housing 3. Figure 6 shows the housing 3 of this embodiment in a perspective view corresponding to Figure 3. In this embodiment, the multiple gate marks 11 are arranged in the circumferential direction of the end face 3Aa of one end side 3A of the housing 3 so as to coincide with the one-end rib 3e.

[0038] [Regarding the operation and effects of EGR valves and their manufacturing methods] As described above, the configuration of the EGR valve 1 in this embodiment is such that the multiple gate marks 11 are arranged in the circumferential direction of the end face 3Aa of one end side 3A of the housing 3, coinciding with the one-end rib 3e. Therefore, when manufacturing the housing 3, the fiber-reinforced molten resin injected from the multiple gates 27 in the mold 21 flows more easily in the axial direction than in the circumferential direction of the cavity 23, as indicated by the arrows in Figure 6. In this respect, although the effect of the roundness of the valve seat 4 is slightly reduced, the same operation and effect as in the first embodiment can be obtained.

[0039] Figure 7 shows the roundness of the valve seat 4 after resin molding shrinkage in this embodiment, as shown in a pie chart. As shown in Figure 7, the degree of shrinkage in this embodiment varies in the range of "13.155 to 13.175", and it can be seen that the roundness is lower than in the first embodiment.

[0040] <Another embodiment> Furthermore, this disclosed technology is not limited to the embodiments described above, and it may be implemented by appropriately modifying some parts of the configuration without departing from the spirit of the disclosed technology.

[0041] (1) In each of the above embodiments, four gate marks 11 are provided in the housing 3, but fewer than four or five or more gate marks may also be provided.

[0042] (2) In each of the above embodiments, a plurality of gate marks 11 are provided on the end face 3Aa of the housing 3 on the side 3A closest to the valve seat 4. However, gate marks may also be provided on the end face 3B opposite to the end face 3A closest to the valve seat 4 of the housing 3.

[0043] (3) In each of the above embodiments, the valve seat 4 is formed integrally with the housing 3, but the valve seat and the housing may be assembled as separate parts.

[0044] (4) In each of the above embodiments, the resin valve device is embodied in the EGR valve 1, but it is not limited to the EGR valve. [Industrial applicability]

[0045] This disclosed technology can be used in valve devices such as EGR valves. [Explanation of symbols]

[0046] 1. EGR valve (plastic valve device) 2 channels 2a entrance 2b exit 3 Housing 3e One-end rib 3f Rib on the other end 3A One end side 3Aa end face 3B Other end side 4 valve seats 5 Valve body 6 Valve stem 7 Drive Unit 11 Gate ruins 21 molds 23 Cavity Gate 27 X-axis direction

Claims

1. A housing formed in a cylindrical shape from fiber-reinforced resin, which includes a flow path including an inlet and an outlet, A valve seat provided in the aforementioned flow path, A valve body is provided in the aforementioned flow path so as to be seatable on the valve seat, The valve stem on which the valve body is provided, A drive unit for driving the valve shaft, In a resin valve device equipped with, The aforementioned housing is It has multiple ribs extending axially and protruding radially on its outer circumferential surface, One end in the axial direction has a cylindrical one-end flange, The valve seat is formed integrally with the housing at one end of the housing, A gate mark from injection molding of molten resin is located on the end face of the flange on one end. The gate marks are arranged in the circumferential direction of the end face of the one-end flange, corresponding to the spaces between adjacent ribs. A resin valve device characterized by the following features.

2. In a manufacturing method for producing a resin valve device as described in claim 1, The housing is formed in the mold cavity from fiber-reinforced molten resin injected from a gate positioned corresponding to the end face of the one-end flange. A method for manufacturing a resin valve device, characterized by the following:

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