JP2021110279A - EGR valve device - Google Patents

Abstract

To provide an EGR valve device which enables improvement of sealability of an elastic seal member while achieving reduction of costs.SOLUTION: An EGR valve device 1 includes: a housing 3 including a passage 2 of an EGR gas; a valve body 5 which opens or closes the passage 2; a valve stem 6 provided with the valve body 5; a bearing 8 provided between the housing 3 and the valve stem 6 and supporting the valve stem 6; an elastic seal member 9 provided between the housing 3 and the valve stem 6 and sealing a gap between the housing 3 and the valve stem 6; and a drive part 7 which drives the valve stem 6 in an axial direction of the valve stem 6. In one embodiment of the disclosure, the elastic seal member 9 is integrated with the bearing 8 by burning.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an EGR valve device that regulates the flow rate of EGR gas in an EGR passage.

As a conventional technique relating to an EGR valve device, Patent Document 1 describes an exhaust in which a bearing that supports a valve shaft and a seal member that suppresses exhaust gas or the like from leaking from a gap between the valve shaft and the bearing to an actuator or the like are integrated. A gas circulation valve device is disclosed.

International Publication No. 2010/018650

In the exhaust gas circulation valve device disclosed in Patent Document 1, the bearing also functions as a plug, and the seal member is held by the bearing. However, a step of causing the bearing to hold the seal member is separately required when assembling the device. It will be necessary and costly. Further, although the seal member is a metal spring material coated with an elastic resin, there is a concern as to whether or not the seal member can be sufficiently brought into close contact with the valve shaft. Therefore, the sealing property of the sealing member may not be sufficient.

Therefore, the present disclosure has been made in order to solve the above-mentioned problems, and an object of the present disclosure is to provide an EGR valve device capable of improving the sealing property of the elastic sealing member while reducing the cost.

One embodiment of the present disclosure made to solve the above problems is a housing provided with an EGR gas flow path, a valve body for opening and closing the flow path, a valve shaft provided with the valve body, and the housing. A bearing provided between the valve shaft and supporting the valve shaft, an elastic sealing member provided between the housing and the valve shaft and sealing between the housing and the valve shaft, and In an EGR valve device having a drive unit for driving the valve shaft in the axial direction of the valve shaft, the elastic seal member is integrated with the bearing by baking.

According to this aspect, the cost of the EGR valve device can be reduced by reducing the number of parts and the assembling process. In addition, the degree of freedom in the shape of the elastic seal member is increased, and the shape can be formed so as to be in close contact with the valve shaft. Therefore, the sealing property of the elastic sealing member can be improved while reducing the cost.

In the above aspect, it is preferable that the baked portion of the elastic sealing member in the bearing is formed in a pipe structure including a tubular portion extending in the axial direction of the bearing.

According to this aspect, the rigidity of the tubular portion makes it possible to secure a tense force in the elastic sealing member. Therefore, the sealing property of the elastic sealing member is improved.

In the above aspect, it is preferable that the tube structure is a plurality of tube structures in which the plurality of tubular portions are provided concentrically around the central axis of the bearing.

According to this aspect, a tense force can be secured both inside and outside in the radial direction of the elastic sealing member. Therefore, the sealing property of the elastic sealing member is improved more effectively. Further, since the elastic seal member is filled in the inner space of the plurality of pipe structures at the time of baking, high holding property of the elastic seal member with respect to the bearing can be obtained.

In the above aspect, the elastic sealing member includes a hole into which the valve shaft is inserted, and comes into contact with the valve shaft at the end of the hole on the valve body side in the axial direction of the valve shaft. Regarding the axial direction of the valve shaft, the length between the end on the bearing side and the end on the valve body side in the hole is larger than the length that the valve shaft drives in the axial direction of the valve shaft. , Are preferred.

According to this aspect, the sealing property and durability of the elastic sealing member can be maintained.

According to the EGR valve device of the present disclosure, the sealing property of the elastic sealing member can be improved while reducing the cost.

It is a front view which shows by cutting a part of the EGR valve device of this embodiment. It is an external view of a valve shaft, a bearing, and an elastic seal member. It is sectional drawing of a valve shaft, a bearing, and an elastic seal member. It is sectional drawing of a bearing and an elastic seal member. It is sectional drawing of the bearing which changed the shape of the hole which inserts a valve shaft, and the elastic seal member. It is sectional drawing of the bearing and elastic seal member of the 1st modification. It is sectional drawing of the bearing and elastic seal member of the 2nd modification. It is sectional drawing of the bearing and elastic seal member of the 3rd modification. It is sectional drawing of the bearing and elastic seal member of the 4th modification.

Hereinafter, embodiments of the EGR valve device of the present disclosure will be described.

<Overview of EGR valve device>
First, the overall outline of the EGR valve device 1 of the present embodiment will be described. The EGR valve device 1 flows an EGR passage (not shown) to an intake passage (not shown) in order to return a part of the exhaust gas discharged from the engine (not shown) to the exhaust passage (not shown) as EGR gas to the engine. It is provided in. The EGR valve device 1 is used to regulate the flow rate of EGR gas in the EGR passage.

As shown in FIG. 1, the EGR valve device 1 has a poppet-type valve structure, a housing 3 having an EGR gas flow path 2, an annular valve seat 4 provided in the middle of the flow path 2, and an annular valve seat 4. A substantially umbrella-shaped valve body 5 provided so as to be seated on the valve seat 4, a valve shaft 6 provided with the valve body 5 at one end, and a valve shaft 6 in the axial direction of the valve shaft 6 (upper and lower in FIG. 1). A drive unit 7 for reciprocating with the valve body 5 is provided in the direction). The drive unit 7 can be configured by, for example, a DC motor. In FIG. 1, a cross-sectional view is shown except for the drive unit 7. The valve seat 4 is formed separately from the housing 3 and is assembled in the middle of the flow path 2. The housing 3 is made of, for example, an aluminum material or a resin material, and the valve seat 4 and the valve body 5 are made of, for example, a resin material or a metal material. The shapes of the valve seat 4 and the valve body 5 are examples. In this embodiment, detailed description of the drive unit 7 will be omitted.

As shown in FIG. 1, the valve shaft 6 extends downward from the drive unit 7 and is fitted into the housing 3. The valve shaft 6 is arranged parallel to the axis of the valve seat 4. The valve body 5 is seated (contacted) and separated from the valve seat 4 by the reciprocating drive of the valve shaft 6, and opens and closes the flow path 2. A bearing 8 for reciprocally supporting the valve shaft 6 is provided between the housing 3 and the valve shaft 6. The material of the bearing 8 is, for example, resin or sintered metal. An elastic sealing member 9 for sealing between the housing 3 and the valve shaft 6 is provided at the lower end of the bearing 8. The elastic sealing member 9 is made of rubber and includes a lip portion 10 that comes into contact with the valve shaft 6. In this embodiment, the valve body 5 is arranged so as to be seatable on the valve seat 4 under the valve seat 4. The elastic seal member 9 is an example of the "elastic seal member" of the present disclosure.

In the EGR valve device 1 having such a configuration, the valve shaft 6 is driven together with the valve body 5 by the drive unit 7, and the valve body 5 is moved with respect to the valve seat 4. As a result, the opening area (opening) between the valve seat 4 and the valve body 5 changes, and the flow rate of the EGR gas in the flow path 2 is adjusted.

<Bearings and elastic seal members>
Next, the bearing 8 and the elastic seal member 9 in this embodiment will be described.

When the bearing 8 and the elastic sealing member 9 are provided separately, the number of parts of the EGR valve device 1 increases, and the body size of the EGR valve device 1 becomes large.

Therefore, as shown in FIGS. 2 to 4, the EGR valve device 1 of the present embodiment has a structure in which the bearing 8 and the elastic seal member 9 are integrally provided. Specifically, the elastic seal member 9 is integrated with the bearing 8 by baking. As a result, the number of parts of the EGR valve device 1 can be reduced and the physique of the EGR valve device 1 can be reduced. Further, since the elastic seal member 9 is integrated with the bearing 8, when assembling the EGR valve device 1, the step of holding the elastic seal member 9 on the bearing 8 becomes unnecessary, which occurs according to the assembly man-hours. The cost can be reduced. Further, since the elastic seal member 9 is assembled to the bearing 8 by baking, the elastic seal member 9 can be brought into close contact with the bearing 8, and the assembled state of the elastic seal member 9 to the bearing 8 is stable. The bearing 8 has a structure in which the role of rotation regulation (regulation of rotation of the valve shaft 6) and the role of shaft regulation (regulation of play in the radial direction of the valve shaft 6) are integrated.

In the present embodiment, as shown in FIG. 4, a baked portion 11 which is an end portion of the bearing 8 on the valve body 5 side (lower side of FIG. 4) and to which the elastic sealing member 9 of the bearing 8 is attached by baking. Is formed in a tubular structure including a tubular portion 12 extending in the axial direction of the bearing 8 (that is, the direction of the central axis CA, the vertical direction in FIG. 4). The tubular portion 12 is formed in a cylindrical shape centered on the central axis CA of the bearing 8. Then, the elastic sealing member 9 is integrated with the bearing 8 by baking so as to be in close contact with the entire tubular portion 12.

In the example shown in FIG. 4, in the pipe structure formed in the baked portion 11 of the bearing 8, the outer tubular portion 12A and the inner tubular portion 12B, which are two tubular portions 12, are concentric with respect to the central axis CA of the bearing 8. It is a double pipe structure provided in. Then, in the radial direction of the bearing 8 (left-right direction in FIG. 4), the outer tubular portion 12A is provided on the outer side, and the inner tubular portion 12B is provided on the inner side. Further, in the axial direction of the bearing 8, the outer tubular portion 12A is formed longer than the inner tubular portion 12B. In other words, in the axial direction of the bearing 8, the end of the outer tubular portion 12A on the valve body 5 side (lower side of FIG. 4) is further than the end of the inner tubular portion 12B on the valve body 5 side. It protrudes to the side.

In this way, the shape of the bearing 8 where the elastic seal member 9 is baked is made into a double pipe structure, and due to the rigidity of the outer tubular portion 12A of this double pipe structure, a tense force (tension force) is applied to the outer diameter side of the elastic seal member 9. That is, the adhesion and holding force with the housing 3) can be secured. On top of that, the elasticity of the lip portion 10 can ensure the adhesion and sealing property with the valve shaft 6. Therefore, the sealing property between the housing 3 and the valve shaft 6 by the elastic sealing member 9 (lip portion 10), that is, the sealing property of the elastic sealing member 9 is improved.

Further, by providing the outer tubular portion 12A and the inner tubular portion 12B as the double pipe structure, it is possible to secure a tense force on both the inner and outer sides of the elastic sealing member 9 in the radial direction. Further, since the elastic seal member 9 can be brought into close contact with the entire circumference of the outer tubular portion 12A and the entire circumference of the inner tubular portion 12B, the adhesive area between the bearing 8 and the elastic seal member 9 can be increased. Further, since the elastic seal member 9 is also filled in the inner space of the double pipe structure (that is, the space between the outer tubular portion 12A and the inner tubular portion 12B) at the time of baking, the elastic seal member 9 of the elastic seal member 9 with respect to the bearing 8. High retention can be obtained.

Further, the elastic seal member 9 includes a valve shaft insertion hole 13 (see FIG. 4) into which the valve shaft 6 is inserted. Here, as shown in FIGS. 2 and 3, the first portion 6a inserted into the bearing 8 in the valve shaft 6 has a width across flats (that is, a shape in which two different diameter portions exist in the circumferential direction). It is formed and has a diameter larger than that of the cylindrical second portion 6b. The first portion 6a is formed on the drive unit 7 side (upper side of FIGS. 2 and 3) with respect to the second portion 6b. Further, the valve shaft insertion hole 14 (see FIG. 4) of the bearing 8 is formed in a shape corresponding to the first portion 6a of the valve shaft 6, and as shown in FIGS. 2 and 3, the first portion 6a of the valve shaft 6 is formed. Reached to the end of the valve shaft insertion hole 14 of the bearing 8 on the elastic seal member 9 side. Further, the valve shaft insertion hole 13 is an example of the "hole portion" of the present disclosure.

Therefore, when the valve shaft 6 is driven toward the valve body 5 side (lower side in FIG. 4) by the drive unit 7 from the state shown in FIGS. 2 and 3 in the axial direction of the valve shaft 6, the first portion 6a of the valve shaft 6 is driven. May enter the inside of the valve shaft insertion hole 13 of the elastic seal member 9 and reach the tip 10a of the lip portion 10 at the end 13b of the valve shaft insertion hole 13 on the valve body 5 side (lower side of FIG. 4). be. Then, the tip 10a of the lip portion 10 of the elastic seal member 9 formed in a circumferential shape comes into contact with the first portion 6a formed in the width across flats of the valve shaft 6, and the elastic seal member 9 Sealability and durability may decrease.

Therefore, in the present embodiment, the stroke portion of the valve shaft 6 (that is, the drive length portion) is released on the elastic seal member 9 side. Specifically, in the axial direction of the valve shaft 6, the length La (see FIG. 4) between the end portion 13a on the bearing 8 side and the end portion 13b on the valve body 5 side in the valve shaft insertion hole 13 is the valve shaft. It is larger than the stroke length Ls of 6 (that is, the length that the valve shaft 6 drives in the axial direction of the valve shaft 6) (see FIG. 3).

As a result, even if the valve shaft 6 is driven in the axial direction of the valve shaft 6, the first portion 6a of the valve shaft 6 is the end portion 13b of the valve shaft insertion hole 13 on the valve body 5 side (lower side in FIG. 4). It is possible to prevent the tip 10a of the lip portion 10 from reaching the tip 10a. Therefore, the tip 10a of the lip portion 10 of the elastic sealing member 9 can be maintained so as not to come into contact with the first portion 6a of the valve shaft 6 and to come into contact with the second portion 6b, so that the sealing property and durability of the elastic sealing member 9 can be maintained. Sex is maintained.

The shape of the valve shaft insertion hole 14 of the bearing 8 may be as shown in FIG. As shown in FIG. 5, in the valve shaft insertion hole 14 of the bearing 8, the first portion 14a having a width across flats into which the first portion 6a of the valve shaft 6 is inserted and the second portion 6b in the valve shaft 6 are inserted. It is provided with a cylindrical second portion 14b to be formed. In this example, even if the valve shaft 6 is driven in the axial direction of the valve shaft 6, it is difficult for the first portion 6a of the valve shaft 6 to reach the tip 10a of the lip portion 10 of the elastic sealing member 9, so that the length is long. It is possible to make La even shorter than in FIG.

<Action and effect of this embodiment>
As described above, in the EGR valve device 1 of the present embodiment, the elastic seal member 9 is integrated with the bearing 8 by baking.

As a result, the cost of the EGR valve device 1 can be reduced by reducing the number of parts of the EGR valve device 1 and the assembly process. Further, the degree of freedom in the shape of the elastic seal member 9 is increased, and the shape can be made so as to be in close contact with the valve shaft 6. Therefore, the sealing property of the elastic sealing member 9 can be improved while reducing the cost.

Further, the baked portion 11 of the elastic sealing member 9 in the bearing 8 is formed in a pipe structure including a tubular portion 12 extending in the axial direction of the bearing 8.

As a result, due to the rigidity of the outer tubular portion 12A of the tubular portion 12, a tense force (that is, an adhesion force and a holding force with the housing 3) can be secured on the outer diameter side of the elastic sealing member 9. On top of that, the elasticity of the lip portion 10 can ensure the adhesion and sealing property with the valve shaft 6. Therefore, the sealing property of the elastic sealing member 9 is improved.

Further, the pipe structure is a double pipe structure in which the outer tubular portion 12A and the inner tubular portion 12B, which are the two tubular portions 12, are provided concentrically around the central axis CA of the bearing 8.

In this way, a tense force can be ensured both inside and outside of the elastic seal member 9 in the radial direction. Therefore, the sealing property of the elastic sealing member 9 is improved more effectively. Further, since the elastic seal member 9 is also filled in the inner space of the double pipe structure (that is, the space between the outer tubular portion 12A and the inner tubular portion 12B) at the time of baking, the elastic seal member 9 of the elastic seal member 9 with respect to the bearing 8. High retention can be obtained.

Further, in the axial direction of the valve shaft 6, the length La between the end portion 13a on the bearing 8 side and the end portion 13b on the valve body 5 side in the valve shaft insertion hole 13 is such that the valve shaft 6 is the shaft of the valve shaft 6. It is larger than the stroke length Ls, which is the length to drive in the direction.

In this way, the sealing property and durability of the elastic sealing member 9 can be maintained.

<About modification>
Further, with respect to the bearing 8 and the elastic seal member 9, the following deformation examples can be considered.

As a first modification, for example, as shown in FIG. 6, the pipe structure has a structure in which one tubular portion 12 is formed, and the tubular portion 12 is convex inward in the radial direction of the bearing 8. The structure may be such that the shape portion 15 is provided. By providing the convex portion 15 in this way, the adhesive area between the bearing 8 and the elastic seal member 9 can be increased, so that the bearing 8 and the elastic seal member 9 can be brought into close contact with each other.

As a second modification, for example, as shown in FIG. 7, the pipe structure has a structure in which one tubular portion 12 is formed, and a bearing is formed inside the bearing 8 of the tubular portion 12 in the radial direction. The structure may be such that a cylindrical convex portion 16 and a cylindrical convex portion 17 projecting from the valve body 5 side (that is, the elastic seal member 9 side) in the axial direction of 8 are provided. By providing the convex portion 16 and the convex portion 17 in this way, the adhesive area between the bearing 8 and the elastic seal member 9 can be increased, so that the bearing 8 and the elastic seal member 9 can be brought into close contact with each other. In other words, in this second modification, it can be said that the pipe structure is a triple pipe structure in which the tubular portion 12, the convex portion 16 and the convex portion 17 are concentrically provided in triplets.

As a third modification, for example, as shown in FIG. 8, the pipe structure has a structure in which one tubular portion 12 is formed, and the tubular portion 12 is provided on the tubular portion 12 in the radial direction of the bearing 8. A structure may be provided in which a through hole 18 is provided. The through hole 18 is provided in the tubular portion 12 in one or more in the circumferential direction of the tubular portion 12. By providing the through hole 18 in this way, the adhesive area between the bearing 8 and the elastic seal member 9 can be increased, so that the bearing 8 and the elastic seal member 9 can be brought into close contact with each other.

As a fourth modification, for example, as shown in FIG. 9, the pipe structure has a structure in which one tubular portion 12 is formed, and a screw-shaped portion is formed inside the bearing 8 of the tubular portion 12 in the radial direction. The structure may be such that 19 is provided. By providing the screw-shaped portion 19 in this way, the adhesive area between the bearing 8 and the elastic seal member 9 can be increased, so that the bearing 8 and the elastic seal member 9 can be brought into close contact with each other.

It should be noted that the above-described embodiment is merely an example and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications can be made without departing from the gist thereof.

For example, the pipe structure is not limited to the double pipe structure as a plurality of pipe structures, and is a structure of triple pipes or more in which three or more tubular portions 12 are concentrically provided about the central axis CA of the bearing 8. May be good.

1 EGR valve device 2 Flow path 3 Housing 4 Valve seat 5 Valve body 6 Valve shaft 6a 1st part 6b 2nd part 7 Drive part 8 Bearing 9 Elastic seal member 10 Lip part 10a Tip 11 Burning part 12 Tubular part 12A Outer tubular part 12B Inner tubular part 13 (elastic seal member) valve shaft insertion hole 13a End part 13b End part 14 (bearing) valve shaft insertion hole 14a 1st part 14b 2nd part 15 Convex part 16 Convex part 17 Convex part 18 Through hole 19 Thread shape CA (bearing) Central shaft La (valve shaft insertion hole) length Ls (valve shaft stroke) length

Claims (4)

A housing with an EGR gas flow path and
A valve body that opens and closes the flow path,
The valve shaft provided with the valve body and
A bearing provided between the housing and the valve shaft and supporting the valve shaft,
An elastic sealing member provided between the housing and the valve shaft and sealing between the housing and the valve shaft.
A drive unit that drives the valve shaft in the axial direction of the valve shaft,
In the EGR valve device having
The elastic sealing member is integrated with the bearing by baking.
EGR valve device characterized by. In the EGR valve device of claim 1,
The baked portion of the elastic sealing member in the bearing is formed in a pipe structure having a tubular portion extending in the axial direction of the bearing.
EGR valve device characterized by. In the EGR valve device of claim 2,
The pipe structure is a plurality of pipe structures in which a plurality of the tubular portions are provided concentrically around the central axis of the bearing.
EGR valve device characterized by. In the EGR valve device according to any one of claims 1 to 3.
The elastic seal member includes a hole into which the valve shaft is inserted, and comes into contact with the valve shaft at the end of the hole on the valve body side in the axial direction of the valve shaft.
Regarding the axial direction of the valve shaft, the length between the end on the bearing side and the end on the valve body side in the hole is larger than the length at which the valve shaft is driven in the axial direction of the valve shaft. ,
EGR valve device characterized by.

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