Fluid Control Valve

Abstract

To provide a fluid control valve which inhibits a backlash and inclination caused by linear expansion in a connection part between a housing and an actuator and inhibits deterioration of sealability between a valve body and a valve seat when the fluid control valve is fully closed.SOLUTION: An EGR valve 1 includes: a resin housing 3 having an EGR gas passage 2; a valve seat 4 provided at the passage 2; a valve body 5 which is provided in such a manner that the valve body can be seated on the valve seat 4; a valve shaft 6 provided with the valve body 5; and an actuator 7 which is connected to the housing 3 and reciprocates the valve shaft 6 in its axial direction. In the valve shaft 6, the valve body 5 is fixed to a lower end 6a and an upper end 6b is drivingly connected to the actuator 7. The actuator 7 includes a resin casing 10 which covers the outer side of the actuator. A connection part 21 which connects an end of the casing 10 with an end of the housing 3 is provided between the actuator 7 and the housing 3. Elastic members 23, 25 which absorb linear expansion of the casing 10 and the housing 3 are disposed at the connection part 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a fluid control valve for controlling the flow rate of a fluid in a flow path. [Background technology]

[0002] A known example of this type of technology is an EGR valve described in Patent Document 1 below. This EGR valve includes a resin housing having an EGR gas passage (flow path) formed therein, a valve seat provided in the flow path, a valve element provided so as to be able to seat on the valve seat, a valve stem for driving the valve element, and an actuator connected to the housing for reciprocating the valve stem in its axial direction. The valve stem has one end and the other end, with the valve element fixed to one end and the other end drivably connected to the actuator. The housing and the actuator are connected by screw fastening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-017506 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the EGR valve described in Patent Document 1, in order to screw-fasten the plastic housing and actuator with a predetermined fastening strength, the connection between the housing and the actuator needs to be thickened. However, thickening the connection increases the size of the EGR valve. Furthermore, linear expansion of the plastic housing can cause the housing to loosen or tilt at the connection. If the housing loosens or tilts, the sealing performance between the valve disc and the valve seat can be degraded when the valve is fully closed.

[0005] This disclosed technology has been made in consideration of the above circumstances, and its purpose is to suppress play at the connection between the housing and the actuator and tilt due to linear expansion in a fluid control valve, and to suppress deterioration of the sealing performance between the valve body and the valve seat when the valve is fully closed. [Means for solving the problem]

[0006] In order to achieve the above object, the technology described in claim 1 includes a resin housing having a fluid flow path therein, a valve seat provided in the flow path, a valve element provided so as to be able to be seated on the valve seat, a valve stem provided with the valve element, and an actuator connected to the housing for reciprocating the valve stem in its axial direction. 、 The valve shaft includes one end and the other end, the valve body is fixed to the one end, and the other end is drivingly connected to the actuator. In this fluid control valve, the actuator On the outside The actuator includes a resin casing, and a connecting portion is provided between the actuator and the housing, connecting an end of the casing to an end of the housing. The connecting portion is provided with a linear expansion coefficient of the casing and the housing. This prevents the seal between the valve body and the valve seat from changing due to the The purpose is to dispose an elastic member.

[0007] According to the configuration of the above technology, an elastic member is disposed at the connection between the end of the actuator casing and the end of the housing to absorb the linear expansion of the casing and the housing. Therefore, even if the resin housing expands linearly and tilts at the connection, the tilt is absorbed by the elastic member.

[0008] In order to achieve the above object, the technology described in claim 2 is the technology described in claim 1, wherein the casing and the housing are connected by thermal caulking at the connection portion. The purpose of this is to

[0009] According to the configuration of the above technology, in addition to the effect of the technology described in claim 1, the casing and housing are connected by thermal crimping at the connection part, which allows for an appropriate amount of play in the connection part. Also, while screw fastening requires the housing flange to be thick, thermal crimping prevents the increase in thickness of the connection part.

[0010] In order to achieve the above object, the technology described in claim 3 is the technology described in claim 2, The casing includes an engagement portion with the housing by thermal caulking, The elastic member is Person in charge The present invention also includes a first elastic member disposed between the mating portion and the housing.

[0011] According to the configuration of the above technology, in addition to the effect of the technology described in claim 2, the first elastic member is disposed between the engagement portion formed by thermal crimping and the housing, so that even if the actuator is misaligned in the axial direction relative to the housing, the misalignment is absorbed by the first elastic member.

[0012] In order to achieve the above object, the technology described in claim 4 is the technology described in claim 2, wherein the elastic member is Between the opposing surfaces of the actuator and the housing that face each other in the axial direction of the valve stem The present invention is intended to include a second elastic member disposed on the

[0013] According to the configuration of the above technology, in addition to the function of the technology described in claim 2, the actuator and the housing Between opposing surfaces facing each other in the axial direction of the valve stem Since the second elastic member is disposed on the housing, even if the housing made of resin undergoes linear expansion and tilts relative to the actuator, the tilt is absorbed by the second elastic member.

[0014] In order to achieve the above object, the technology described in claim 5 is the technology described in claim 3, wherein the elastic member is Between the opposing surfaces of the actuator and the housing that face each other in the axial direction of the valve stem The present invention is intended to include a second elastic member disposed on the

[0015] According to the configuration of the above technology, in addition to the function of the technology described in claim 3, the actuator and the housing Between opposing surfaces facing each other in the axial direction of the valve stemSince the second elastic member is disposed on the housing, even if the housing made of resin undergoes linear expansion and tilts relative to the actuator, the tilt is absorbed by the second elastic member.

[0016] In order to achieve the above object, the technology described in claim 6 is the technology described in claim 5, wherein the thickness of the second elastic member is thinner than the thickness of the first elastic member.

[0017] According to the configuration of the above technology, in addition to the effect of the technology described in claim 5, since the thickness of the second elastic member is thinner than the thickness of the first elastic member, the absorption of the tilt of the housing by the second elastic member is less likely to affect the absorption of the positional deviation of the actuator by the first elastic member.

[0018] In order to achieve the above object, the technology described in claim 7 is the technology described in claim 5 or 6, in which the hardness of the second elastic member is higher than the hardness of the first elastic member.

[0019] According to the configuration of the above technology, in addition to the effect of the technology described in claim 5 or 6, since the hardness of the second elastic member is higher than the hardness of the first elastic member, the absorption of the tilt of the housing by the second elastic member is less likely to affect the absorption of the positional deviation of the actuator by the first elastic member. [Effects of the Invention]

[0020] According to the technology described in claim 1, the fluid control valve can suppress play at the connection between the housing and the actuator and tilt due to linear expansion, thereby suppressing deterioration of the sealing performance between the valve body and the valve seat when fully closed.

[0021] According to the technology described in claim 2, in addition to the effect of the technology described in claim 1, it is possible to suppress the deterioration of the function of suppressing play at the connection part and tilt due to linear expansion, prevent the elastic member from being crushed, and suppress the bulkiness of the connection part.

[0022] According to the technology described in claim 3, in addition to the effect of the technology described in claim 2, it is possible to suppress the positional deviation of the valve body relative to the valve seat when the valve is opened, thereby improving the flow rate controllability of the fluid control valve.

[0023] According to the technology recited in claim 4, in addition to the effect of the technology recited in claim 2, it is possible to further suppress deterioration of the sealing performance between the valve body and the valve seat when the valve is fully closed.

[0024] According to the technology recited in claim 5, in addition to the effect of the technology recited in claim 3, it is possible to further suppress deterioration of the sealing performance between the valve body and the valve seat when the valve is fully closed.

[0025] According to the technology described in claim 6, in addition to the effect of the technology described in claim 5, it is possible to suppress a decrease in the function of improving the flow controllability of the fluid control valve when the valve is open, and to suppress a decrease in the sealing performance between the valve body and the valve seat when the valve is closed.

[0026] According to the technology described in claim 7, in addition to the effect of the technology described in claim 5 or 6, it is possible to suppress a decrease in the function of improving the flow controllability of the fluid control valve when the valve is open, and to suppress a deterioration in the sealing performance between the valve body and the valve seat when the valve is closed. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 2 is a front view showing the EGR valve in a fully closed state in the first embodiment. [Figure 2] FIG. 2 is a plan view showing the EGR valve in the first embodiment. [Figure 3] 3 is a cross-sectional view taken along line AA in FIG. 2, showing the EGR valve in a fully closed state according to the first embodiment. [Figure 4] 4 is an enlarged cross-sectional view showing a portion enclosed by a dashed-dotted rectangle in FIG. 3, including a connection portion, according to the first embodiment. [Figure 5] FIG. 10 is a front view showing the EGR valve in a fully closed state according to the second embodiment. [Figure 6] FIG. 4 is a cross-sectional view equivalent to FIG. 3 showing the EGR valve in a fully closed state according to a second embodiment. [Figure 7]FIG. 5 is an enlarged cross-sectional view equivalent to FIG. 4 showing a connection portion according to a second embodiment. [Figure 8] FIG. 11 is a front view showing the EGR valve in a fully closed state according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view equivalent to FIG. 3 showing the EGR valve in a fully closed state according to a third embodiment. [Figure 10] FIG. 10 is an enlarged cross-sectional view equivalent to FIG. 4 showing a connection portion according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment in which the fluid control valve is embodied as an exhaust gas recirculation valve (EGR valve) will be described below.

[0029] First Embodiment The first embodiment will be described in detail with reference to the drawings.

[0030] [EGR valve configuration] First, the configuration of the EGR valve will be described. Fig. 1 shows a front view of the EGR valve 1 in a fully closed state. Fig. 2 shows a plan view of the EGR valve 1. Fig. 3 shows a cross-sectional view of the EGR valve 1 in a fully closed state taken along line AA in Fig. 2. This EGR valve 1 is provided in an EGR passage that allows a portion of the exhaust gas emitted from the engine to flow into an intake passage as EGR gas, and is used to adjust the flow rate of the EGR gas, and corresponds to an example of a fluid control valve of the disclosed technology.

[0031] As shown in FIGS. 1 to 3, the EGR valve 1 has a poppet valve structure and includes a resin housing 3 having an internal flow path 2 for EGR gas as a fluid; a resin valve seat 4 provided in the flow path 2 and molded integrally with the housing 3; a metal valve element 5 provided to be able to seat on the valve seat 4 and forming a measuring section for EGR gas between the valve seat 4; a metal valve stem 6 provided with the valve element 5; and an actuator 7 connected to the housing 3 for reciprocating the valve stem 6 in its axial direction. The actuator 7 is, for example, configured by a step motor. The actuator 7 is configured to reciprocate (stroke) the valve stem 6 together with the valve element 5 in the axial direction. In this EGR valve 1, the valve stem 6 includes a lower end (one end) 6a and an upper end (the other end) 6b in FIGS. 1 to 3. The valve element 5 is fixed to the lower end 6a, and the upper end 6b is drivably connected to the actuator 7. The EGR valve 1 adjusts the flow rate of EGR gas in the flow passage 2 by changing the opening area of ​​the metering portion when an actuator 7 moves a valve element 5 relative to a valve seat 4. The two ends of the flow passage 2 are an inlet 2a through which the EGR gas is introduced and an outlet 2b through which the EGR gas is discharged.

[0032] As shown in FIG. 3 , the valve stem 6 is disposed vertically penetrating the housing 3, and its upper end 6b is drivingly connected to the actuator 7 via a screw mechanism 8. A thrust bearing 9 is provided between the housing 3 and the valve stem 6 to support the valve stem 6 so that it can perform stroke motion. The thrust bearing 9 is generally cylindrical and is fixed in an assembly hole 3a formed in the center of the housing 3. The actuator 7 includes a resin casing 10 that covers the actuator 7. In FIGS. 1 and 3 , the casing 10 has a flange 10a at its lower end. As shown in FIG. 3 , the EGR valve 1 is attached to a pipe 11 that forms an EGR passage. That is, the pipe 11 has an assembly hole 11b formed in the middle of its flow path 22a. The EGR valve 1 is attached (dropped in) to the assembly hole 11b, and the flange 10a of the actuator 7 is fastened to the pipe 11 with bolts (not shown). In this embodiment, detailed description of other components of the actuator 7 will be omitted.

[0033] [Actuator and housing connection structure] Here, the connection structure between the actuator 7 and the housing 3 will be described. As shown in FIG. 3, the upper end of the housing 3 is flush with the lower end of the actuator 7. A connection portion 21 is provided between the actuator 7 and the housing 3, connecting the lower end of the casing 10 and the upper end of the housing 3. FIG. 4 shows an enlarged cross-sectional view of the portion surrounded by a dashed-dotted rectangle S1 in FIG. 3, including the connection portion 21. In FIGS. 3 and 4, the connection portion 21 is indicated by an oval circle surrounded by a dashed-dotted line. A first elastic member 23 is disposed in the connection portion 21 to absorb linear expansion of the casing 10 and the housing 3. The casing 10 and the housing 3 are connected by thermal caulking at the connection portion 21. That is, a flange 3b is integrally formed at the upper end of the housing 3. A plurality of protruding protrusions 10b are integrally formed at the lower end of the casing 10, so as to enclose the flange 3b of the housing 3. The flange 3b of the housing 3 is joined to the lower end of the actuator 7 and surrounded by a plurality of projecting plates 10b, each of which is connected to the lower surface of the flange 3b by thermal caulking. The first elastic member 23 is annular, and is disposed between an engaging portion 24 bent by thermal caulking between the casing 10 and the housing 3, and the lower surface of the flange 3b of the housing 3. The first elastic member 23 is made of, for example, a rubber material.

[0034] [About the function and effect of the EGR valve] According to the configuration of the EGR valve 1 (fluid control valve) in this embodiment described above, a first elastic member 23 (elastic member) is disposed at the connection portion 21 between the end of the casing 10 of the actuator 7 and the end of the housing 3 to absorb linear expansion of the casing 10 and the housing 3. Therefore, even if the resin housing 3 linearly expands and tilts at the connection portion 21, the tilt is absorbed by the first elastic member 23. Therefore, in the EGR valve 1, it is possible to suppress play at the connection portion 21 between the housing 3 and the actuator 7 and tilt due to linear expansion, thereby suppressing deterioration of the sealing performance between the valve element 5 and the valve seat 4 when the valve is fully closed.

[0035] According to the configuration of this embodiment, the casing 10 and the housing 3 are connected by thermal crimping at the connection portion 21, which allows for an appropriate amount of play in the connection portion 21. Furthermore, while screw fastening requires that the flange 3b of the housing 3 be thick, thermal crimping prevents an increase in the thickness of the connection portion 21. This prevents a decrease in the function of suppressing play and tilt due to linear expansion at the connection portion 21, prevents crushing of the first elastic member 23, and reduces the bulkiness of the connection portion 21.

[0036] According to the configuration of this embodiment, the first elastic member 23 is disposed between the housing 3 and the engagement portion 24 formed by thermal caulking, so even if the actuator 7 is displaced in the axial direction relative to the housing 3, the displacement is absorbed by the first elastic member 23. Therefore, it is possible to suppress displacement of the valve element 5 relative to the valve seat 4 when the valve is open, and it is possible to improve the flow controllability of the EGR valve 1.

[0037] Second Embodiment Next, the second embodiment will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment will be denoted by the same reference numerals and will not be described again, and differences will be mainly described.

[0038] [EGR valve configuration] This embodiment differs from the first embodiment mainly in the configuration of the connection portion 21. Fig. 5 is a front view of the EGR valve 1 in a fully closed state. Fig. 6 is a cross-sectional view equivalent to Fig. 3 of the EGR valve 1 in a fully closed state. As shown in Figs. 5 and 6, the basic configuration of the EGR valve 1 of this embodiment is the same as that of the first embodiment.

[0039] [Actuator and housing connection structure] Here, the connection structure between the actuator 7 and the housing 3 will be described. As shown in FIG. 6 , in this embodiment, the upper end of the housing 3 is flush with the lower end of the actuator 7. A connection portion 21 is provided between the actuator 7 and the housing 3, connecting the lower end of the casing 10 to the upper end of the housing 3. FIG. 7 is an enlarged cross-sectional view of the portion surrounded by the dashed-dotted rectangle S1 in FIG. 6 , including the connection portion 21. In this embodiment, a second elastic member 25 is disposed in the connection portion 21 to absorb the linear expansion of the casing 10 and the housing 3. The casing 10 and the housing 3 are connected at the connection portion 21 by thermal caulking. That is, the flange 3b of the housing 3 is joined to the lower end of the actuator 7 and surrounded by multiple projecting plates 10b, and each projecting plate 10b is connected to the lower surface of the flange 3b by an engaging portion 24 bent by thermal caulking. Here, the second elastic member 25 is disposed at the mating surface between the actuator 7 and the flange 3b of the housing 3. The second elastic member 25 is made of, for example, a rubber material.

[0040] [About the function and effect of the EGR valve] According to the configuration of the EGR valve 1 (fluid control valve) in this embodiment described above, unlike the first embodiment, the second elastic member 25 is disposed on the mating surface between the actuator 7 and the housing 3. Therefore, even if the resin housing 3 linearly expands and tilts relative to the actuator 7, the tilt is absorbed by the second elastic member 25. Therefore, deterioration of the sealing performance between the valve body 5 and the valve seat 4 when the EGR valve 1 is fully closed can be further suppressed.

[0041] Third Embodiment Next, a third embodiment will be described in detail with reference to the drawings.

[0042] [EGR valve configuration] This embodiment differs from the above-described embodiments mainly in the configuration of the connection portion 21. Fig. 8 is a front view of the EGR valve 1 in a fully closed state. Fig. 9 is a cross-sectional view equivalent to Fig. 3 of the EGR valve 1 in a fully closed state. As shown in Figs. 8 and 9, the basic configuration of the EGR valve 1 of this embodiment is the same as that of the above-described embodiments.

[0043] [Actuator and housing connection structure] Here, the connection structure between the actuator 7 and the housing 3 will be described. As shown in FIG. 9, in this embodiment as well, a connection portion 21 is provided between the actuator 7 and the housing 3, connecting the lower end of the casing 10 and the upper end of the housing 3. FIG. 10 is an enlarged cross-sectional view of the connection portion 21, which is a portion surrounded by a dash-dotted rectangle S1 in FIG. 9. In this embodiment, a first elastic member 23 and a second elastic member 25 are disposed in the connection portion 21 to absorb the linear expansion of the casing 10 and the housing 3. The casing 10 and the housing 3 are connected at the connection portion 21 by thermal caulking. That is, the flange 3b of the housing 3 is joined to the lower end of the actuator 7 and surrounded by multiple projecting plates 10b, and each projecting plate 10b is connected to the lower surface of the flange 3b by an engaging portion 24 bent by thermal caulking. Here, the first elastic member 23 is disposed between an engaging portion 24 bent by thermal caulking between the casing 10 and the housing 3 and the underside of the flange 3b of the housing 3. The second elastic member 25 is disposed on the mating surface between the actuator 7 and the flange 3b of the housing 3. In this embodiment, the thickness of the second elastic member 25 is thinner than the thickness of the first elastic member 23. The first and second elastic members 23, 25 are made of, for example, a rubber material.

[0044] [About the function and effect of the EGR valve] According to the configuration of the EGR valve 1 (fluid control valve) in this embodiment described above, in addition to the actions and effects of the first embodiment, the following actions and effects can be obtained. That is, since the second elastic member 25 is disposed on the mating surface between the actuator 7 and the housing 3, even if the resin housing 3 linearly expands and tilts relative to the actuator 7, the tilt is absorbed by the second elastic member 25. Therefore, deterioration of the sealing performance between the valve disc 5 and the valve seat 4 when the EGR valve 1 is fully closed can be further suppressed.

[0045] According to the configuration of this embodiment, the thickness of the second elastic member 25 is thinner than the thickness of the first elastic member 23, so the absorption of tilt of the housing 3 by the second elastic member 25 is less likely to affect the absorption of positional deviation of the actuator 7 by the first elastic member 23. Therefore, the function of improving the flow controllability of the EGR valve 1 can be suppressed when the valve is open, and the deterioration of the sealing performance between the valve body 5 and the valve seat 4 can be suppressed when the valve is closed.

[0046] [Modification of the third embodiment] A modification of the third embodiment will be described. This modification differs from the third embodiment in the following respects. Specifically, the hardness of the second elastic member 25 is higher than that of the first elastic member 23. Therefore, according to this modification, the hardness of the second elastic member 25 is higher than that of the first elastic member 23, so that absorption of the tilt of the housing 3 by the second elastic member 25 is less likely to affect absorption of the positional deviation of the actuator 7 by the first elastic member 23. In this sense, too, the function of improving the flow controllability of the EGR valve 1 when the valve is open can be suppressed, and deterioration of the sealing performance between the valve body 5 and the valve seat 4 can be suppressed when the valve is closed.

[0047] <Another embodiment> The disclosed technology is not limited to the above-described embodiments, and can be implemented by appropriately modifying part of the configuration within the scope of the disclosed technology.

[0048] For example, in each of the above embodiments, the fluid control valve of this disclosed technology is embodied in the EGR valve 1, but it can also be embodied in a valve other than the EGR valve 1, for example, a bypass valve provided in a bypass passage of an EGR cooler. [Industrial Applicability]

[0049] The disclosed technology can be used in EGR devices installed in gasoline engines and diesel engines. [Explanation of symbols]

[0050] 1 EGR valve (fluid control valve) 2 Flow path 3. Housing 4 Valve seat 5 Valve body 5 6 Valve stem 6a Lower end 6b Upper end 7 Actuators 10 Casing 21 Connection 23 First elastic member 24 Engagement part 25 Second elastic member

Claims

1. a resin housing having a fluid flow path therein; a valve seat provided in the flow path; a valve body that is capable of being seated on the valve seat; a valve stem provided with the valve body; an actuator connected to the housing for reciprocating the valve stem in its axial direction; Equipped with a valve shaft including one end and another end, the valve body being fixed to the one end, and the other end being drivingly connected to the actuator; The actuator includes an outer resin casing, a connecting portion that connects an end of the casing and an end of the housing is provided between the actuator and the housing, An elastic member is disposed in the connecting portion to suppress changes in the sealing performance between the valve body and the valve seat due to linear expansion of the casing and the housing. A fluid control valve characterized by:

2. 2. The fluid control valve according to claim 1, The casing and the housing are connected at the connection portion by thermal caulking. A fluid control valve characterized by:

3. 3. The fluid control valve according to claim 2, the casing includes an engagement portion with the housing by the thermal caulking, The elastic member includes a first elastic member disposed between the engaging portion and the housing. A fluid control valve characterized by:

4. 3. The fluid control valve according to claim 2, The elastic member includes a second elastic member disposed between opposing surfaces of the actuator and the housing that face each other in the axial direction of the valve stem. A fluid control valve characterized by:

5. 4. The fluid control valve according to claim 3, The elastic member further includes a second elastic member disposed between opposing surfaces of the actuator and the housing that face each other in the axial direction of the valve stem. A fluid control valve characterized by:

6. 6. The fluid control valve according to claim 5, The thickness of the second elastic member is thinner than the thickness of the first elastic member. A fluid control valve characterized by:

7. 7. The fluid control valve according to claim 5 or 6, The hardness of the second elastic member is higher than the hardness of the first elastic member. A fluid control valve characterized by:

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