WO2010061509A1

WO2010061509A1 - Egr valve device and method of assembling valve stem

Info

Publication number: WO2010061509A1
Application number: PCT/JP2009/004532
Authority: WO
Inventors: 田中徹
Original assignee: 三菱電機株式会社
Priority date: 2008-11-25
Filing date: 2009-09-11
Publication date: 2010-06-03
Also published as: JP2012026270A

Abstract

A valve stem is formed by axially joining a plurality of stems having holding parts for holding valve elements, respectively. While the valve element of one valve stem is brought into contact with one valve seat for closing the valve, the valve stem for supporting the valve element is slidably supported inside a housing with bearings interposed therebetween. Then, the valve element of the other valve stem is brought into contact with the other valve seat for closing the valve, and while the closed state of the valve is maintained, the valve stems are joined to each other in the axial direction.

Description

EGR valve device and valve shaft assembling method

The present invention relates to a multi-valve EGR (Exhaust Gas Recirculation) valve device that guides and circulates part of exhaust gas after combustion in an internal combustion engine to the intake side, and a valve shaft assembling method of the EGR valve device.

In order to ensure a large flow rate in a limited space, this multi-valve EGR valve device is operated by, for example, operating a single valve shaft with two valve bodies in the axial direction to open the exhaust gas. There is a two-valve type EGR valve device that recirculates gas.
In addition, in this two-valve EGR valve device, a configuration is disclosed in which the valve leakage is suppressed by changing the material of the valve seat or reviewing the distance relationship between the valve seats in order to prevent the valve leakage due to the difference in thermal expansion of the material. (For example, refer to Patent Document 1).

JP 2001-099014 A

Although the conventional multi-valve EGR valve device has a shaft length, the valve shaft to which the valve body is attached is longer than the single-valve EGR valve device, and is manufactured by cutting or the like. The accuracy of was bad. Therefore, when a plurality of valve bodies are attached to the valve shaft and assembled to the housing, there is a problem that a gap is generated between the valve seat on the housing side and the valve body on the valve shaft side.
In addition, when assembling the valve shaft, the gap between the valve seat and the valve body cannot be adjusted, and there is a problem that the amount of leakage varies greatly.

The present invention has been made in order to solve the above-described problems, and provides an EGR valve device that increases the accuracy of the coaxiality of the valve shaft and suppresses the gap between the valve seat and the valve body. It is an object of the present invention to provide a method for assembling a valve shaft that can be assembled by adjusting the positions of a valve seat and a valve body when assembling a valve to a housing.

An EGR valve device according to the present invention includes a housing in which an exhaust gas passage connecting the exhaust gas inlet and the exhaust gas outlet is formed, a valve seat provided in the housing in the middle of the exhaust gas passage, and a bearing in the housing. A slidably supported valve shaft, a biasing member that urges the valve shaft in a direction in which the valve body held by the valve shaft contacts the valve seat, and a valve shaft in a direction in which the valve body separates from the valve seat The valve shaft is formed by fastening a plurality of shafts each having a holding portion for holding the valve body in the axial direction.

The valve shaft assembly method according to the present invention is such that, in a state where the valve body of one valve shaft is in contact with one valve seat and is closed, the valve shaft that holds the valve body is supported in the housing. The valve body of the other valve shaft is brought into contact with the other valve seat and closed, and the valve shaft is held in the axial direction while maintaining the closed state. is there.

The EGR valve device according to the present invention is configured so that, for example, two valve shafts having a holding portion for holding the valve body are fastened in the axial length direction to form one valve shaft. It is possible to increase the accuracy and suppress the gap between the valve seat and the valve body. Further, since the valve shaft is fastened as a single valve shaft with the valve body in contact with the valve seat, the valve shaft is assembled by adjusting the position of the valve seat and the valve body when the valve shaft is assembled to the housing. It is possible to suppress the gap between the valve seat and the valve body.

It is the longitudinal cross-sectional view which notched a part of EGR valve apparatus of this invention. It is sectional drawing which decomposed | disassembled the valve shaft of the EGR valve apparatus by Embodiment 1 of this invention, and longitudinally cut the right half. It is a fragmentary sectional view showing the state (a) in which a valve element and a valve seat are contacting, and the state (b) in which a crevice has arisen. It is a figure (a)-(c) which shows the assembly method of the valve axis of a EGR valve device of this invention, and a valve element. It is sectional drawing (a), (b) which cut longitudinally the valve shaft and the right half of the valve body of the EGR valve apparatus by Embodiment 3 of this invention. It is sectional drawing which cut | disconnected longitudinally the valve shaft and the right half of the valve body of the EGR valve apparatus by Embodiment 5 of this invention.

Hereinafter, in order to describe the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view in which a part of an EGR valve device 1 of the present invention is cut out, and FIG. 2 is a sectional view in which the right half of the valve shaft of the EGR valve device 1 according to Embodiment 1 is longitudinally cut. .

The housing 10 of the EGR valve device 1 has one exhaust gas inlet 21 and two

exhaust gas outlets

22 and 23, and the exhaust gas passage 20 that branches from the inlet 21 to the

outlets

22 and 23 is formed. Valve

seats

31 and 32 each having a central hole are provided in the middle.

A valve shaft 50 is slidably mounted in the axial direction on a central axis inside the housing 10 via a bearing sliding support member (bearing) 40. The valve shaft 50 includes

valve shafts

51, 52 is fastened. The valve shaft 50 is formed with

holding portions

51a and 52a at positions corresponding to the

valve seats

31 and 32 provided in the housing 10, and the

valve bodies

60a and 60b are held by the

holding portions

51a and 52a. Yes. Further, a spring holder 71 is attached to the upper portion of the valve shaft 50, and the springs (biasing members) 72 provided between the spring holder 71 and the housing 10 are always provided with

valve bodies

60a and 60b. The valve shaft 50 is urged in the direction in which the

seats

31 and 32 abut.
The detailed configuration of the valve shaft 50 will be described later.

A motor 80 as an actuator is mounted on the upper portion of the housing 10, and the valve shaft 60 is driven in a direction in which the

valve bodies

60 a and 60 b are separated from the

valve seats

31 and 32 by the motor shaft 81 of the motor 80. .

The bottom 90 of the housing 10 is opened for assembling the valve shaft 50 in the housing, but is closed by a sealing member 91 after the valve shaft 50 is assembled.

The EGR valve device 1 is configured as described above. When an internal combustion engine such as an engine (not shown) is operated, the motor 80 is driven, and the motor shaft 81 screwed into the screw hole at the center of the rotor is rotated by the rotation of the rotor. Move in the direction. The motor shaft 81 contacts the upper end of the valve shaft 50 and moves the valve shaft 50 in the axial direction against the urging force of the spring 72. When the valve shaft 50 moves, an opening passage is formed between the

valve bodies

60a and 60b and the

valve seats

31 and 32, and the opening degree of the exhaust gas passage 20 is adjusted by the amount of movement of the valve shaft 50, thereby reducing the exhaust gas circulation amount. adjust.

Here, the detailed structure of the valve shaft 50 and the

valve bodies

60a and 60b will be described.
As shown in FIG. 2, the valve shaft 50 of the EGR valve device 1 according to the first embodiment includes a divided upper valve shaft 51 and lower valve shaft 52. The valve shaft 51 is formed with a holding portion 51a for attaching the valve body 60a, and the valve shaft 52 is formed with a holding portion 52a for attaching the valve body 60b.
The lower end of the valve shaft 51 and the upper end of the valve shaft 52 are formed with a concave portion 51b and a convex portion 52b as fastening portions, and in a state where the concave portion 51b and the convex portion 52b are engaged, for example, adhesion or welding Fasten by fastening, press-fitting, screwing, pinning, etc.

Next, a method of assembling the

valve shafts

51 and 52 and the

valve bodies

60a and 60b to the housing 10 will be described.
FIG. 3 is a partial cross-sectional view showing a state (a) in which the valve body 60 and the

valve seat

31 or 32 are in contact with each other and a state (b) in which a gap is generated, and FIG. FIG. 6 is a diagram (a) to (c) showing a method of assembling the

valve shafts

51 and 52 and the

valve bodies

60a and 60b.

When two

valve bodies

60a and 60b are attached to one valve shaft of a conventional EGR valve device, the accuracy of the coaxiality of the shaft is poor, so that one valve body 60a is a valve seat as shown in FIG. Even if assembled so as to be in contact with 31, the other valve body 60b has a gap 150 between the valve seat 32 and the valve body 60b as shown in FIG. Therefore, in the EGR valve device 1 of the first embodiment, the

valve shafts

51 and 52 are assembled as follows.

First, since the valve body 60a cannot pass through the central holes of the

valve seats

31 and 32, for example, the valve body 60a is inserted into the housing 10 from the inlet 21 and the valve body 60a is inserted into the valve seat 31 as shown in FIG. The valve shaft 51 is inserted from the open bottom 90 of the housing 10, passed through the center hole of the valve body 60a, and the valve body 60a is fixed to the holding portion 51a (B). At this time, the valve shaft 51 is slidably supported by the housing 10 via the bearing sliding support member 40. Next, as shown in FIG. 4 (b), the lower valve body 60b is inserted from the bottom 90 of the housing 10 and pressed against the valve seat 32 to be closed (C), and the valve shaft 52 is moved to the valve body. Pass through the center hole of 60b (D). And as shown in FIG.4 (c), the valve body 60b is fixed to the holding | maintenance part 52a in the state which each contacted and closed the valve seat 31 and the valve body 60a, and the valve seat 32 and the valve body 60b. Further, the concave portions 51b and the convex portions 52b facing each other of the

valve shafts

51 and 52 are engaged, and the concave and convex engaging portions are fastened by bonding, welding, press-fitting, screwing, pinning, or the like (E). However, it is not limited to the shape and fastening method of these fastening portions, and any shape or method may be used as long as the upper and

lower valve shafts

51 and 52 are fastened without rattling depending on the use environment.

By fastening in this way, the accuracy of the coaxiality between the valve shaft 50 and other components such as the housing 10 and the bearing sliding support member 40 can be increased. As a result, the valve seats 31 and 32 and the valve There is almost no gap between the

bodies

60a and 60b, and the amount of exhaust gas leakage can be suppressed.

As described above, according to the EGR valve device 1 of the first embodiment, the two

valve shafts

51 and 52 obtained by dividing the valve shaft 50 are configured to be fastened in the axial direction, and the valve body of one valve shaft 51 is used. When the valve shaft 51 is slidably supported in the housing 10 via the bearing sliding support member 40 in a state where the valve seat 60a is in contact with the one valve seat 31 and closed, the other valve shaft 52 is supported. The valve body 60b is brought into contact with the other valve seat 32 to be closed, and the valve seat 31 is closed by engaging the concavity and convexity portions facing the

valve shafts

51 and 52 while maintaining the closed state. The gap between the valve body 60 and the

valve bodies

60a and 60b can be suppressed, and the positions of the valve seats 31 and 32 and the

valve bodies

60a and 60b can be adjusted when the

valve shafts

51 and 52 are assembled.

Embodiment 2. FIG.
In the first embodiment, the configuration in which the valve shaft 50 of the EGR valve device 1 is divided and the valve shaft 51 and the valve shaft 52 are fastened has been described. However, the second embodiment holds the fastened

valve shafts

51 and 52. A configuration in which the

valve bodies

60a and 60b are shared by making the shapes of the

portions

51a and 52a the same will be described.
The configuration of the second embodiment will be described with reference to FIGS. 1 and 2, and the same components as those described in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

In the conventional two-valve EGR valve device, since a plurality of valve bodies must be attached to one long valve shaft, the diameter of the center hole of the lower valve body is larger than the diameter of the center hole of the upper valve body. It was necessary to create two types of valve bodies.
On the other hand, in the EGR valve device 1 of the second embodiment, the shape of the holding

portions

51a and 52a of the valve shaft 51 and the valve shaft 52 is the same, and the

valve bodies

60a and 60b attached to the holding

portions

51a and 52a are: It is the valve body of the same shape which formed the center hole of the same diameter corresponding to the shape of holding |

maintenance part

51a, 52a.

As described above, according to the EGR valve device 1 of the second embodiment, the

valve bodies

60a and 60b have the same shape by making the shape of the holding

portions

51a and 52a of the valve shaft 51 and the valve shaft 52 the same. As a result, the

valve bodies

60a and 60b can be shared.

Embodiment 3 FIG.
In the first embodiment, the EGR valve device 1 configured by dividing the valve shaft 50 and fastening the upper valve shaft 51 and the lower valve shaft 52 is shown. However, the third embodiment has different axial lengths. The configuration of the valve shaft 50 in which the shaft is fastened in the axial length direction will be described.

FIG. 5A is a view showing the valve shaft 50 of the EGR valve device in which the distance h between the valve seat 31 and the valve seat 32 is longer than that of the EGR valve device 1 of the first embodiment. (B) is a figure which shows the valve shaft 50 of the EGR valve apparatus which is the short distance i between the valve seat 31 and the valve seat 32 compared with the EGR valve apparatus 1 of Embodiment 1. FIG. In addition, about structures other than the valve shaft 50, it is substantially the same as Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

Since the conventional EGR valve device is composed of a single valve shaft, in the case of an EGR valve device with a different shaft length, one valve shaft must be designed and processed with a new setting. Therefore, in Embodiment 3, the valve shaft 50 is formed by fastening

valve shafts

53 and 54 having different axial lengths in the axial length direction as shown in FIGS. 5 (a) and 5 (b).

The valve shaft 53 is formed with such a length that the distance h between the valve body 60a and the valve body 60b is fastened to the valve shaft 51. Further, the valve shaft 54 is formed with a length that is a distance i between the valve body 60a and the valve body 60b by being fastened to the valve shaft 51.

In the EGR valve device 1 in which the distance between the valve seat 31 and the valve seat 32 is a distance h, the valve shaft 51 and the valve shaft 53 are fastened in the axial length direction as shown in FIG. Is assembled to the housing 10.
Further, in the EGR valve device 1 having a distance i between the valve seat 31 and the valve seat 32, as shown in FIG. Assemble to 10.

In the EGR valve device 1 according to the third embodiment, the configuration in which the lower valve shaft 52 is replaced with the

valve shafts

53 and 54 with different shaft lengths has been described. However, the EGR valve device with a different specification from the valve seat 31 is used. In the case of 1, the upper valve shaft 51 may be replaced with a shaft having a different axial length.

Thus, according to the EGR valve device 1 of the third embodiment, instead of the upper valve shaft 51 or the lower valve shaft 52, a valve shaft having a different axial length is fastened in the axial length direction. The

shafts

51, 52, 53, 54 can be shared, and can be made compatible with the EGR valve device 1 having different specifications of the shaft length.

Embodiment 4 FIG.
In the first, second, and third embodiments, the

valve shafts

51, 52, 53, and 54 obtained by dividing the valve shaft 50 are used. However, in the fourth embodiment, the material of at least one valve shaft to be fastened is the other valve. An example of a configuration in which a material having a lower coefficient of thermal expansion than the material of the shaft will be described.
The configuration of the EGR valve device 1 according to the fourth embodiment is substantially the same as the configuration of the EGR valve device 1 according to the first to third embodiments, and will be described with reference to FIGS. 1 to 5 as appropriate. Are denoted by the same reference numerals, and the description thereof is omitted.

Normally, the material of the valve shaft 50 is stainless steel in order to provide corrosion resistance, for example, austenitic stainless steel. The material of the

valve shafts

52, 53, 54 on the lower side of the valve shaft 50 may be a material different from that of the valve shaft 51, for example, a material having a low coefficient of thermal expansion.

As described above, according to the EGR valve device 1 of the fourth embodiment, the material of at least one of the

valve shafts

52, 53, 54 to be fastened is made of a material having a lower coefficient of thermal expansion than that of the other valve shaft 51. The thermal expansion of the valve shaft can be suppressed, and as a result, the gap between the valve seats 31 and 32 and the

valve bodies

60a and 60b can be suppressed.

In addition, although the example which changed the material of the

lower valve shaft

52,54,55 to the material with a low thermal expansion coefficient was demonstrated, what changed the material of the upper valve shaft 51 to the material with a low thermal expansion coefficient, and was comprised. But you can.

Further, if the upper valve shaft 51 is made of a material having a low coefficient of thermal expansion in advance, a better leakage performance can be secured.

Embodiment 5 FIG.
In the EGR valve device 1 according to the first to fourth embodiments, the upper valve shaft 51 to be fastened and the

lower valve shafts

52, 53, and 54 are formed of the same rod-shaped shafts. The EGR valve device 1 will be described with a configuration in which at least one valve shaft to be fastened is provided with a weight reducing means.

FIG. 6 is a diagram showing a configuration of a valve shaft 50 using a cylindrical valve shaft 55 instead of the lower rod-shaped

valve shafts

52, 53, 54 of the EGR valve device 1. The configuration of the EGR valve device 1 of the fifth embodiment is substantially the same as the configuration of the EGR valve device 1 of the first to fourth embodiments, and will be described with reference to FIGS. 1 to 5 as appropriate. Description of is omitted.

As shown in FIG. 6, the divided lower valve shaft 55 of the EGR valve device 1 has a cylindrical shape with a hollow center portion, and the appearance is the same as the

valve shafts

52, 53, and 54. .

In addition, the valve shaft 55 subjected to the weight reduction means is not limited to the cylindrical shape, and may be any shape set within a range of strength required for the valve shaft 55. For example, a rod-shaped valve shaft By using the valve shaft 55 in which the outermost diameters of 52, 53, and 54 are smaller than the outermost diameter of the valve shaft 51, weight reduction can be realized. However, by using the cylindrical valve shaft 55, the valve shaft 55 can be easily processed.

In addition, although the configuration in which the lower valve shaft 55 is provided with the weight reduction means has been described, the weight reduction means may be provided within the range of strength required for the upper valve shaft 51 and the like.

Thus, according to the EGR valve device 1 of the fifth embodiment, the valve shaft 55 can be smoothly operated by reducing the weight of the tightened lower valve shaft 55, for example, in a cylindrical shape. Can do.

As described above, in the EGR valve device according to the present invention, the valve shaft is configured by fastening a plurality of shafts each having a holding portion for holding the valve body in the axial direction. It can be fastened while maintaining the closed state by contacting the valve seat of the housing. As a result, a gap between the valve seat and the valve body can be suppressed.

In the first to fifth embodiments, an example of the configuration in the two-valve type EGR valve device has been shown, but the same effect can be obtained when applied to an EGR valve device having a configuration in which a plurality of valve bodies are provided on the same axis. It is done.

In the first to fifth embodiments, the configuration in which the valve shaft 50 of the two-valve EGR valve device 1 is divided and the valve shaft 51 and any of the

valve shafts

52, 53, 54, 55 are fastened has been described. If the dimensions match, the valve shaft 51 or the like can be shared as the valve shaft of the single valve EGR valve device.

The EGR valve device and the valve shaft assembly method according to the present invention increase the accuracy of the coaxiality of the valve shaft, and can be assembled by adjusting the position of the valve seat and the valve body when the valve shaft is assembled to the housing. For this reason, the gap between the valve seat and the valve body can be suppressed. For this reason, it is suitable for use in a multi-valve EGR valve device or the like in which a part of exhaust gas after combustion is led to the intake side and circulated in an internal combustion engine.

Claims

A housing in which an exhaust gas passage connecting the exhaust gas inlet and the exhaust gas outlet is formed,
A valve seat provided in the housing in the middle of the exhaust gas passage;
A valve shaft slidably supported in the housing via a bearing;
An urging member for urging the valve shaft in a direction in which a valve body held by the valve shaft abuts on the valve seat;
An actuator that drives the valve shaft in a direction in which the valve body separates from the valve seat;
The valve shaft is formed by fastening a plurality of shafts each having a holding portion for holding the valve body in the axial direction.
2. The EGR valve device according to claim 1, wherein the shape of the holding portion of each shaft to be fastened is the same.
2. The EGR valve device according to claim 1, wherein the valve shaft is formed by fastening shafts having different shaft lengths in the shaft length direction.
2. The EGR valve device according to claim 1, wherein the valve shaft is made of a material having a coefficient of thermal expansion lower than that of the other shaft.
2. The EGR valve device according to claim 1, wherein the valve shaft is subjected to weight reduction means.
In a state where the valve body of one valve shaft is in contact with the one valve seat and closed, after supporting the valve shaft holding this valve body in the housing through a bearing,
A valve shaft assembling method for an EGR valve device characterized in that the valve body of the other valve shaft is brought into contact with the other valve seat and closed, and the valve shaft is held in the axial direction while maintaining the closed state. .