JP6869834B2

JP6869834B2 - Exhaust control valve

Info

Publication number: JP6869834B2
Application number: JP2017132594A
Authority: JP
Inventors: 英士中村; 吉岡　衛; 衛吉岡
Original assignee: Aisan Industry Co Ltd
Current assignee: Aisan Industry Co Ltd
Priority date: 2017-07-06
Filing date: 2017-07-06
Publication date: 2021-05-12
Anticipated expiration: 2037-07-06
Also published as: JP2019015221A

Description

この明細書に開示される技術は、エンジンの排気系に設けられ、排気の流れを制御するために使用される排気制御弁に関する。 The technology disclosed herein relates to an exhaust control valve provided in the exhaust system of an engine and used to control the flow of exhaust.

従来、この種の技術として、例えば、下記の特許文献１に記載される技術（「排気ガス切替弁」）が知られている。この技術は、排気ガスの流路を含むハウジングと、流路を貫通するようにハウジングに配置された弁軸と、流路にて弁軸と一体に設けられた弁体と、弁軸の両端部を回転可能に支持するためにハウジングに設けられた一対のブッシュ型の軸受と、弁軸の両端部にて軸受と流路との間にて弁軸とハウジングとの間に設けられたシール部材とを備えたＥＧＲクーラバイパスバルブに関する。ここで、両軸受は、滑り軸受であり、弁軸とハウジングとの間に接触状態で介在されており、排気ガスから弁軸に伝わる熱をハウジングへ伝えることでシール部材の過熱を抑制する手段を構成している。 Conventionally, as this kind of technology, for example, the technology described in Patent Document 1 below (“exhaust gas switching valve”) is known. This technology uses a housing that includes an exhaust gas flow path, a valve shaft that is arranged in the housing so as to penetrate the flow path, a valve body that is integrally provided with the valve shaft in the flow path, and both ends of the valve shaft. A pair of bush-type bearings provided in the housing to rotatably support the portion, and a seal provided between the valve shaft and the housing between the bearing and the flow path at both ends of the valve shaft. The present invention relates to an EGR cooler bypass valve provided with a member. Here, both bearings are slide bearings, which are interposed between the valve shaft and the housing in a contact state, and are means for suppressing overheating of the seal member by transferring the heat transferred from the exhaust gas to the valve shaft to the housing. Consists of.

特開２０１０−２０３３６２号公報JP-A-2010-203362

ところで、特許文献１に記載の技術では、流路と軸受とシール部材との配置の関係において、軸受がその軸方向に所定の軸受幅を有する。この軸受幅が大きいほどシール部材の過熱抑制効果が高くなり、シール部材の耐熱性を向上させることができる。しかしながら、軸受の軸方向における端面から流路までの端面距離等の要素によっては、過熱抑制効果に関する上記関係が成り立たなくなる場合があることがわかってきた。例えば、端面距離を一定とした場合、軸受幅を大きくすると、シール部材が流路に近付くことになり、シール部材が過熱しやすくなってしまう。そこで、流路と軸受とシール部材との配置や寸法の関係において、シール部材の耐熱性を向上させることができる最適な軸受幅が問題となる。 By the way, in the technique described in Patent Document 1, the bearing has a predetermined bearing width in the axial direction in relation to the arrangement of the flow path, the bearing, and the seal member. The larger the bearing width, the higher the effect of suppressing overheating of the seal member, and the heat resistance of the seal member can be improved. However, it has been found that the above relationship regarding the overheat suppressing effect may not be established depending on factors such as the end face distance from the end face to the flow path in the axial direction of the bearing. For example, when the end face distance is constant and the bearing width is increased, the seal member approaches the flow path, and the seal member tends to overheat. Therefore, in relation to the arrangement and dimensions of the flow path, the bearing, and the seal member, the optimum bearing width capable of improving the heat resistance of the seal member becomes a problem.

この開示技術は、上記事情に鑑みてなされたものであって、その目的は、流路と軸受とシール部材との配置や寸法の関係において、シール部材の耐熱性を有効に向上させることを可能とした排気制御弁を提供することにある。 This disclosure technique was made in view of the above circumstances, and its purpose is to be able to effectively improve the heat resistance of the seal member in relation to the arrangement and dimensions of the flow path, the bearing, and the seal member. The purpose is to provide an exhaust control valve.

上記目的を達成するために、請求項１に記載の技術は、排気の流路を含むケーシングと、流路を貫通してケーシングに配置された弁軸と、弁軸は軸端部を含むことと、流路に配置され、弁軸と一体に設けられた弁体と、弁軸をケーシングに対して回転可能に支持するために軸端部に設けられた滑り軸受と、滑り軸受はその軸方向において第１端と第２端を含むことと、弁体と滑り軸受との間にて滑り軸受の第１端に接して配置され、軸端部とケーシングとの間をシールするためのシール部材と、シール部材は軸端部と接する部分の軸方向において第１端と第２端を含み、第２端が滑り軸受の第１端と接することとを備え、弁軸を回転させて弁体を開閉させることにより、流路における排気の流れを制御するように構成した排気制御弁において、弁軸の軸方向における距離であって、滑り軸受の第２端から、流路においてシール部材に最も近い壁面までの距離を端面距離（Ｌe）と定義し、シール部材の第１端から第２端までの距離をシール距離（Ｌｓ）と定義し、軸端部の直径を軸径（Ｄｓ）と定義し、弁軸の軸方向における距離であって、滑り軸受の軸方向における幅を軸受幅（Ｗｂ）と定義すると、シール部材の温度を低くするために、軸受幅（Ｗｂ）を以下の式（Ｆ１）を満たすように設定した
Ｗｂ＝Ａ＋Ｂ＊Ｌｅ−Ｃ＊Ｌｓ＋（Ｅ＋Ｆ）＊Ｄｓ・・・（Ｆ１）
Ａ，Ｂ，Ｃ，Ｅ，Ｆ：所定の係数
Ｗｂ≦Ｌｅ−Ｌｓ
ことを趣旨とする。 In order to achieve the above object, the technique according to claim 1 includes a casing including an exhaust flow path, a valve shaft arranged in the casing through the flow path, and the valve shaft including a shaft end portion. A valve body arranged in the flow path and integrally provided with the valve shaft, a sliding bearing provided at the shaft end for rotatably supporting the valve shaft with respect to the casing, and the sliding bearing are the shafts. A seal that includes the first and second ends in the direction and is placed between the valve body and the sliding bearing in contact with the first end of the sliding bearing to seal between the shaft end and the casing. The member and the seal member include the first end and the second end in the axial direction of the portion in contact with the shaft end portion, the second end is in contact with the first end of the sliding bearing, and the valve shaft is rotated to valve. In an exhaust control valve configured to control the flow of exhaust in the flow path by opening and closing the body, it is the distance in the axial direction of the valve shaft from the second end of the sliding bearing to the seal member in the flow path. The distance to the nearest wall surface is defined as the end face distance (Le), the distance from the first end to the second end of the sealing member is defined as the sealing distance (Ls), and the diameter of the shaft end is defined as the shaft diameter (Ds). If the axial distance of the valve shaft and the axial width of the sliding bearing are defined as the bearing width (Wb), the bearing width (Wb) is set to the following in order to lower the temperature of the sealing member. Wb = A + B * Le-C * Ls + (E + F) * Ds ... (F1) set to satisfy the equation (F1).
A, B, C, E, F: Predetermined coefficient
Wb ≤ Le-Ls
The purpose is that.

上記目的を達成するために、請求項２に記載の技術は、排気の流路を含むケーシングと、流路を貫通してケーシングに配置された弁軸と、弁軸は軸端部を含むことと、流路に配置され、弁軸と一体に設けられた弁体と、弁軸をケーシングに対して回転可能に支持するために軸端部に設けられた滑り軸受と、滑り軸受はその軸方向において第１端と第２端を含むことと、弁体と滑り軸受との間にて滑り軸受の第１端に接して配置され、軸端部とケーシングとの間をシールするためのシール部材と、シール部材は軸端部と接する部分の軸方向において第１端と第２端を含み、第２端が滑り軸受の第１端と接することとを備え、弁軸を回転させて弁体を開閉させることにより、流路における排気の流れを制御するように構成した排気制御弁において、弁軸の軸方向における距離であって、滑り軸受の第２端から、流路においてシール部材に最も近い壁面までの距離を端面距離（Ｌe）と定義し、シール部材の第１端から第２端までの距離をシール距離（Ｌｓ）と定義し、軸端部の直径を軸径（Ｄｓ）と定義し、流路とシール部材との間にて軸端部の外周に括れが設けられ、括れの直径を括れ径（Ｄｎ）と定義し、弁軸の軸方向における距離であって、滑り軸受の軸方向における幅を軸受幅（Ｗｂ）と定義すると、シール部材の温度を低くするために、軸受幅（Ｗｂ）を以下の式（Ｆ２）を満たすように設定した
Ｗｂ＝Ａ＋Ｂ＊Ｌｅ−Ｃ＊Ｌｓ＋Ｅ＊Ｄｓ＋Ｆ＊Ｄｎ・・・（Ｆ２）
Ａ，Ｂ，Ｃ，Ｅ，Ｆ：所定の係数
Ｗｂ≦Ｌｅ−Ｌｓ
ことを趣旨とする。 In order to achieve the above object, the technique according to claim 2 includes a casing including an exhaust flow path, a valve shaft arranged in the casing through the flow path, and the valve shaft including a shaft end portion. A valve body arranged in the flow path and integrally provided with the valve shaft, a sliding bearing provided at the shaft end for rotatably supporting the valve shaft with respect to the casing, and the sliding bearing are the shafts. A seal that includes the first and second ends in the direction and is placed between the valve body and the sliding bearing in contact with the first end of the sliding bearing to seal between the shaft end and the casing. The member and the seal member include the first end and the second end in the axial direction of the portion in contact with the shaft end portion, the second end is in contact with the first end of the sliding bearing, and the valve shaft is rotated to valve. In an exhaust control valve configured to control the flow of exhaust in the flow path by opening and closing the body, it is the distance in the axial direction of the valve shaft from the second end of the sliding bearing to the seal member in the flow path. The distance to the nearest wall surface is defined as the end face distance (Le), the distance from the first end to the second end of the sealing member is defined as the sealing distance (Ls), and the diameter of the shaft end is defined as the shaft diameter (Ds). A constriction is provided on the outer circumference of the shaft end between the flow path and the seal member, and the diameter of the constriction is defined as the constriction diameter (Dn), which is the distance in the axial direction of the valve shaft and slips. If the width of the bearing in the axial direction is defined as the bearing width (Wb), the bearing width (Wb) is set to satisfy the following equation (F2) in order to lower the temperature of the sealing member. Wb = A + B * Le- C * Ls + E * Ds + F * Dn ... (F2)
A, B, C, E, F: Predetermined coefficient
Wb ≤ Le-Ls
The purpose is that.

請求項１及び２に記載の技術によれば、流路と軸受とシール部材との配置や寸法の関係において、シール部材の耐熱性を有効に向上させることができる。 According to the techniques according to claims 1 and 2, the heat resistance of the seal member can be effectively improved in relation to the arrangement and dimensions of the flow path, the bearing and the seal member.

第１実施形態に係り、ＥＧＲクーラバイパスバルブを備えた並列フロー式のＥＧＲクーラユニットの概略を示す断面図。FIG. 5 is a cross-sectional view illustrating an outline of a parallel flow type EGR cooler unit provided with an EGR cooler bypass valve according to the first embodiment. 第１実施形態に係り、バイパスバルブを示す断面図。FIG. 5 is a cross-sectional view showing a bypass valve according to the first embodiment. 第１実施形態に係り、図２の一部であって、バイパス流路、バイパス弁体、第２シール部材、滑り軸受及び第２軸端部の部分を拡大して示す断面図。FIG. 2 is a cross-sectional view which is a part of FIG. 2 and shows an enlarged view of a bypass flow path, a bypass valve body, a second seal member, a slide bearing, and a second shaft end portion according to the first embodiment. 第１実施形態に係り、端面距離を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the bearing width when the end face distance is changed according to 1st Embodiment. 第１実施形態に係り、軸径を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the bearing width when the shaft diameter is changed according to 1st Embodiment. 第１実施形態に係り、シール距離を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。A graph showing the relationship of the sealing temperature with respect to the bearing width when the sealing distance is changed according to the first embodiment. 第１実施形態に係り、括れ径に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the constriction diameter which concerns on 1st Embodiment. 第１実施形態に係り、熱源からの距離に対する弁軸温度との関係を示すグラフ。A graph showing the relationship between the valve shaft temperature and the distance from the heat source according to the first embodiment. 第１実施形態に係り、式（Ｆ２Ａ）によって得られた各種パラメータの関係を示す表。A table showing the relationship between various parameters obtained by the formula (F2A) according to the first embodiment. 第１実施形態に係り、シール温度と寿命の関係を示すグラフ。A graph showing the relationship between the seal temperature and the life according to the first embodiment. 第２実施形態に係り、バイパス流路、バイパス弁体、第２シール部材、滑り軸受及び第２軸端部の部分を拡大して示す図３に準ずる断面図。FIG. 3 is a cross-sectional view according to FIG. 3 in which the bypass flow path, the bypass valve body, the second seal member, the slide bearing, and the portion of the second shaft end are enlarged according to the second embodiment. 第２実施形態に係り、端面距離を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the bearing width at the time of changing the end face distance which concerns on 2nd Embodiment. 第２実施形態に係り、軸径を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the bearing width when the shaft diameter is changed according to 2nd Embodiment. 第２実施形態に係り、シール距離を変えた場合の軸受幅に対するシール温度の関係を示すグラフ。The graph which shows the relationship of the seal temperature with respect to the bearing width when the seal distance is changed according to 2nd Embodiment.

＜第１実施形態＞
以下、排気制御弁をＥＧＲクーラユニットに使用されるＥＧＲクーラバイパスバルブに具体化した第１実施形態につき図面を参照して詳細に説明する。 <First Embodiment>
Hereinafter, the first embodiment in which the exhaust control valve is embodied in the EGR cooler bypass valve used in the EGR cooler unit will be described in detail with reference to the drawings.

[ＥＧＲクーラユニットの概要について]
図１に、この実施形態のＥＧＲクーラバイパスバルブ（以下、単に「バイパスバルブ」という。）１を備えた並列フロー式のＥＧＲクーラユニット２の概略を断面図により示す。このＥＧＲクーラユニット２は、ＥＧＲ通路（図示略）の途中に設けられ、クーラケーシング３と、クーラケーシング３の入口側に設けられた入口パイプ４と、クーラケーシング３の出口側に設けられたバイパスバルブ１及び出口パイプ５とを備える。クーラケーシング３は、クーラ通路６と、クーラ通路６を迂回したバイパス通路７と、クーラ通路６の入口６ａとバイパス通路７の入口７ａが合流する合流部８とを含む。クーラ通路６とバイパス通路７は互いに並列に配置される。入口パイプ４は合流部８に接続される。バイパスバルブ１は、クーラ通路６の出口６ｂとバイパス通路７の出口７ｂに接続される。出口パイプ５は、バイパスバルブ１の出口側に接続される。クーラ通路６には、エンジンの冷却水が流れる熱交換器９が設けられる。クーラ通路６と熱交換器９によりＥＧＲクーラが構成される。入口パイプ４と出口パイプ５は、それぞれＥＧＲ通路に接続される。入口パイプ４に流入したＥＧＲガスは、クーラ通路６を通過することで熱交換器９により冷却される。バイパス通路７を通過するＥＧＲガスは冷却されない。 [Overview of EGR cooler unit]
FIG. 1 shows an outline of a parallel flow type EGR cooler unit 2 provided with the EGR cooler bypass valve (hereinafter, simply referred to as “bypass valve”) 1 of this embodiment by a cross-sectional view. The EGR cooler unit 2 is provided in the middle of the EGR passage (not shown), the cooler casing 3, the inlet pipe 4 provided on the inlet side of the cooler casing 3, and the bypass provided on the outlet side of the cooler casing 3. It includes a valve 1 and an outlet pipe 5. The cooler casing 3 includes a cooler passage 6, a bypass passage 7 bypassing the cooler passage 6, and a confluence portion 8 where the inlet 6a of the cooler passage 6 and the inlet 7a of the bypass passage 7 meet. The cooler passage 6 and the bypass passage 7 are arranged in parallel with each other. The inlet pipe 4 is connected to the merging portion 8. The bypass valve 1 is connected to the outlet 6b of the cooler passage 6 and the outlet 7b of the bypass passage 7. The outlet pipe 5 is connected to the outlet side of the bypass valve 1. A heat exchanger 9 through which cooling water for the engine flows is provided in the cooler passage 6. The EGR cooler is composed of the cooler passage 6 and the heat exchanger 9. The inlet pipe 4 and the outlet pipe 5 are each connected to the EGR passage. The EGR gas that has flowed into the inlet pipe 4 is cooled by the heat exchanger 9 by passing through the cooler passage 6. The EGR gas passing through the bypass passage 7 is not cooled.

[バイパスバルブについて]
図２に、この実施形態のバイパスバルブ１を断面図により示す。図１、図２に示すように、このバイパスバルブ１は、ＥＧＲクーラ（クーラ通路６及び熱交換器９）と、バイパス通路７とを含むクーラケーシング３と共に使用され、ＥＧＲクーラを通過するＥＧＲガスの流量と、バイパス通路７を通過するＥＧＲガスの流量とを同時に調節するようになっている。このバイパスバルブ１は、主要な構成要素として、バルブケーシング１１、二つの弁体１２，１３、弁軸１４、減速機構１５及びＤＣモータ１６を備える。バルブケーシング１１は、二つの流路１７，１８を含むアルミ製の本体ケーシング１９と、本体ケーシング１９の開口端を閉鎖する合成樹脂製のエンドフレーム２０とを含む。二つの弁体１２，１３、弁軸１４及びＤＣモータ１６は、本体ケーシング１９に設けられる。減速機構１５は、本体ケーシング１９とエンドフレーム２０との間に設けられる。 [About bypass valve]
FIG. 2 shows a cross-sectional view of the bypass valve 1 of this embodiment. As shown in FIGS. 1 and 2, the bypass valve 1 is used together with a cooler casing 3 including an EGR cooler (cooler passage 6 and heat exchanger 9) and a bypass passage 7, and an EGR gas passing through the EGR cooler. And the flow rate of the EGR gas passing through the bypass passage 7 are adjusted at the same time. The bypass valve 1 includes a valve casing 11, two valve bodies 12, 13, a valve shaft 14, a speed reduction mechanism 15, and a DC motor 16 as main components. The valve casing 11 includes an aluminum main body casing 19 including two flow paths 17 and 18, and a synthetic resin end frame 20 that closes the open end of the main body casing 19. The two valve bodies 12, 13, the valve shaft 14, and the DC motor 16 are provided in the main body casing 19. The speed reduction mechanism 15 is provided between the main body casing 19 and the end frame 20.

本体ケーシング１９は、クーラ通路６の出口６ｂに連通するクーラ流路１７と、バイパス通路７の出口７ｂに連通するバイパス流路１８とを含み、クーラ流路１７とバイパス流路１８とが隔壁２１を介して仕切られる。クーラ流路１７には、クーラ通路６を通過したＥＧＲガスが流れる。バイパス流路１８には、バイパス通路７を通過したＥＧＲガスが流れる。クーラ流路１７には、同流路１７を開閉するための板状をなすクーラ弁体１２が配置される。バイパス流路１８には、同流路１８を開閉するための板状をなすバイパス弁体１３が配置される。この実施形態で、クーラ弁体１２及びバイパス弁体１３はそれぞれバタフライ式弁体であり、一つの弁軸１４に一体に固定される。弁軸１４は、本体ケーシング１９にて、クーラ流路１７、隔壁２１及びバイパス流路１８を貫通して配置される。クーラ弁体１２は、クーラ流路１７にて弁軸１４に固定され、バイパス弁体１３は、バイパス流路１８にて弁軸１４に固定される。また、クーラ弁体１２とバイパス弁体１３は、互いに位相を所定角度ずらした状態で弁軸１４に固定される。従って、弁軸１４を一方向へ回転させることにより、クーラ弁体１２が開方向へ回動すると共に、バイパス弁体１３が閉方向へ回動する。一方、弁軸１４を逆方向へ回転させることにより、クーラ弁体１２が閉方向へ回動すると共に、バイパス弁体１３が開方向へ回動する。図２は、クーラ弁体１２が全閉でバイパス弁体１３が全開の状態を示す。 The main body casing 19 includes a cooler flow path 17 communicating with the outlet 6b of the cooler passage 6 and a bypass flow path 18 communicating with the outlet 7b of the bypass passage 7, and the cooler flow path 17 and the bypass flow path 18 form a partition wall 21. It is partitioned through. The EGR gas that has passed through the cooler passage 6 flows through the cooler passage 17. The EGR gas that has passed through the bypass passage 7 flows through the bypass passage 18. In the cooler flow path 17, a plate-shaped cooler valve body 12 for opening and closing the flow path 17 is arranged. In the bypass flow path 18, a plate-shaped bypass valve body 13 for opening and closing the flow path 18 is arranged. In this embodiment, the cooler valve body 12 and the bypass valve body 13 are butterfly valve bodies, respectively, and are integrally fixed to one valve shaft 14. The valve shaft 14 is arranged in the main body casing 19 so as to penetrate the cooler flow path 17, the partition wall 21, and the bypass flow path 18. The cooler valve body 12 is fixed to the valve shaft 14 at the cooler flow path 17, and the bypass valve body 13 is fixed to the valve shaft 14 at the bypass flow path 18. Further, the cooler valve body 12 and the bypass valve body 13 are fixed to the valve shaft 14 in a state where the phases of the cooler valve body 12 and the bypass valve body 13 are shifted from each other by a predetermined angle. Therefore, by rotating the valve shaft 14 in one direction, the cooler valve body 12 rotates in the opening direction and the bypass valve body 13 rotates in the closing direction. On the other hand, by rotating the valve shaft 14 in the opposite direction, the cooler valve body 12 rotates in the closing direction and the bypass valve body 13 rotates in the opening direction. FIG. 2 shows a state in which the cooler valve body 12 is fully closed and the bypass valve body 13 is fully open.

図２に示すように、弁軸１４を本体ケーシング１９に対して回転可能に支持するために弁軸１４の両端部には一対をなす軸受２２，２３が設けられる。弁軸１４は、その両端に第１軸端部１４ａと第２軸端部１４ｂを含む。二つの弁体１２，１３は、第１軸端部１４ａと第２軸端部１４ｂとの間にて弁軸１４上に固定される。クーラ弁体１２は、第１軸端部１４ａに隣接して配置され、バイパス弁体１３は、第２軸端部１４ｂに隣接して配置される。ここで、第１軸端部１４ａは、クーラ弁体１２より外側（弁軸１４の一端側）の全範囲を含み、第２軸端部１４ｂは、バイパス弁体１３より外側（弁軸１４の他端側）の全範囲を含むと定義することができる。本体ケーシング１９と第１軸端部１４ａとの間には、転がり軸受（ボールベアリング）２２が設けられる。一方、本体ケーシング１９と第２軸端部１４ｂとの間には、滑り軸受２３が設けられる。本体ケーシング１９には、第２軸端部１４ｂの先端に対応して、プラグ２４が設けられる。また、クーラ弁体１２と転がり軸受２２との間にて、転がり軸受２２のクーラ弁体１２に近い側面には、その側面に隣接して、第１軸端部１４ａと本体ケーシング１９との間をシールするための第１シール部材２６が設けられる。更に、バイパス弁体１３と滑り軸受２３との間にて、滑り軸受２３のバイパス弁体１３に近い側面には、その側面に接して、第２軸端部１４ｂと本体ケーシング１９との間をシールするための第２シール部材２７が設けられる。両シール部材２６，２７は、樹脂又はゴムより形成される。これらシール部材２６，２７として、例えば、「ＰＴＦＥシール」を採用することができる。第１シール部材２６は、クーラ流路１７から第１軸端部１４ａと本体ケーシング１９との間への異物や水分の侵入を防止するようになっている。第２シール部材２７は、バイパス流路１８から第２軸端部１４ｂと本体ケーシング１９との間への異物や水分の侵入を防止するようになっている。 As shown in FIG. 2, in order to rotatably support the valve shaft 14 with respect to the main body casing 19, a pair of bearings 22 and 23 are provided at both ends of the valve shaft 14. The valve shaft 14 includes a first shaft end portion 14a and a second shaft end portion 14b at both ends thereof. The two valve bodies 12 and 13 are fixed on the valve shaft 14 between the first shaft end portion 14a and the second shaft end portion 14b. The cooler valve body 12 is arranged adjacent to the first shaft end portion 14a, and the bypass valve body 13 is arranged adjacent to the second shaft end portion 14b. Here, the first shaft end portion 14a includes the entire range outside the cooler valve body 12 (one end side of the valve shaft 14), and the second shaft end portion 14b is outside the bypass valve body 13 (of the valve shaft 14). It can be defined as including the entire range (on the other end side). A rolling bearing (ball bearing) 22 is provided between the main body casing 19 and the first shaft end portion 14a. On the other hand, a slide bearing 23 is provided between the main body casing 19 and the second shaft end portion 14b. The main body casing 19 is provided with a plug 24 corresponding to the tip of the second shaft end portion 14b. Further, between the cooler valve body 12 and the rolling bearing 22, on the side surface of the rolling bearing 22 near the cooler valve body 12, adjacent to the side surface, between the first shaft end portion 14a and the main body casing 19. A first sealing member 26 is provided for sealing the. Further, between the bypass valve body 13 and the slide bearing 23, on the side surface of the slide bearing 23 close to the bypass valve body 13, in contact with the side surface, between the second shaft end portion 14b and the main body casing 19. A second sealing member 27 for sealing is provided. Both sealing members 26 and 27 are made of resin or rubber. As these seal members 26 and 27, for example, "PTFE seal" can be adopted. The first seal member 26 is designed to prevent foreign matter and moisture from entering between the cooler flow path 17 and the first shaft end portion 14a and the main body casing 19. The second seal member 27 is designed to prevent foreign matter and moisture from entering between the bypass flow path 18 and the second shaft end portion 14b and the main body casing 19.

図２において、エンドフレーム２０は、本体ケーシング１９に対し複数のクリップ（図示略）により着脱可能に固定される。エンドフレーム２０の内側には、弁軸１４の第１軸端部１４ａに対応して配置され、各弁体１２，１３の開度（バルブ開度）を検出するための開度センサ３１が設けられる。この開度センサ３１は、ホールＩＣ等により構成され、弁軸１４の回転角度をバルブ開度として検出するように構成される。第１軸端部１４ａの先端には、樹脂ギヤであるメインギヤ３２が固定される。ここで、第１軸端部１４ａの先端は、金属製のレバー２８を介してメインギヤ３２に接続され、メインギヤ３２と一体回転可能に構成される。また、メインギヤ３２と本体ケーシング１９との間には、各弁体１２，１３を閉方向又は開方向へ付勢するためのリターンスプリング３３が設けられる。メインギヤ３２の表側には、凹部３２ａが形成され、その凹部３２ａには磁石３４が収容される。この磁石３４は、板ばねよりなる押さえ板３５により押さえ付けられて固定される。従って、メインギヤ３２が、各弁体１２，１３及び弁軸１４と一体に回転することにより、磁石３４の磁界が変化し、その磁界の変化を開度センサ３１がバルブ開度として検出するようになっている。 In FIG. 2, the end frame 20 is detachably fixed to the main body casing 19 by a plurality of clips (not shown). Inside the end frame 20, an opening sensor 31 is provided so as to correspond to the first shaft end portion 14a of the valve shaft 14 and to detect the opening degree (valve opening degree) of each of the valve bodies 12 and 13. Be done. The opening degree sensor 31 is composed of a Hall IC or the like, and is configured to detect the rotation angle of the valve shaft 14 as the valve opening degree. A main gear 32, which is a resin gear, is fixed to the tip of the first shaft end portion 14a. Here, the tip of the first shaft end portion 14a is connected to the main gear 32 via a metal lever 28, and is configured to be integrally rotatable with the main gear 32. Further, a return spring 33 for urging the valve bodies 12 and 13 in the closing direction or the opening direction is provided between the main gear 32 and the main body casing 19. A recess 32a is formed on the front side of the main gear 32, and the magnet 34 is housed in the recess 32a. The magnet 34 is pressed and fixed by a pressing plate 35 made of a leaf spring. Therefore, when the main gear 32 rotates integrally with the valve bodies 12, 13 and the valve shaft 14, the magnetic field of the magnet 34 changes, and the opening sensor 31 detects the change in the magnetic field as the valve opening. It has become.

この実施形態で、ＤＣモータ１６は、本体ケーシング１９の凹部１９ａに収容され、その両端が留め材３６と板ばね３７を介して本体ケーシング１９に固定される。そして、図１、図２に示すように、ＤＣモータ１６は、各弁体１２，１３を開閉駆動するために、減速機構１５を介して弁軸１４に駆動連結される。ＤＣモータ１６の出力軸１６ａ上には、モータギヤ３８が固定される。モータギヤ３８は、中間ギヤ３９を介してメインギヤ３２に駆動連結される。中間ギヤ３９は、大径ギヤ３９ａと小径ギヤ３９ｂを含む二段ギヤであり、ピンシャフト４０を介して本体ケーシング１９に回転可能に支持される。大径ギヤ３９ａには、モータギヤ３８が連結され、小径ギヤ３９ｂには、メインギヤ３２が連結される。この実施形態では、メインギヤ３２、中間ギヤ３９及びモータギヤ３８により減速機構１５が構成され、メインギヤ３２と中間ギヤ３９は、軽量化のために樹脂より形成される。 In this embodiment, the DC motor 16 is housed in a recess 19a of the main body casing 19, and both ends thereof are fixed to the main body casing 19 via a fastener 36 and a leaf spring 37. Then, as shown in FIGS. 1 and 2, the DC motor 16 is driven and connected to the valve shaft 14 via the speed reduction mechanism 15 in order to open and close the valve bodies 12 and 13. A motor gear 38 is fixed on the output shaft 16a of the DC motor 16. The motor gear 38 is driven and connected to the main gear 32 via the intermediate gear 39. The intermediate gear 39 is a two-stage gear including a large-diameter gear 39a and a small-diameter gear 39b, and is rotatably supported by the main body casing 19 via a pin shaft 40. The motor gear 38 is connected to the large diameter gear 39a, and the main gear 32 is connected to the small diameter gear 39b. In this embodiment, the reduction mechanism 15 is composed of the main gear 32, the intermediate gear 39, and the motor gear 38, and the main gear 32 and the intermediate gear 39 are made of resin for weight reduction.

このバイパスバルブ１は、弁軸１４を回転させて各弁体１２，１３を開閉させることにより、各流路１７，１８におけるＥＧＲガスの流れを制御するように構成される。従って、図２に示すように、クーラ弁体１２が全閉及びバイパス弁体１３が全開の状態から、ＤＣモータ１６が通電により作動し、モータギヤ３８が一方向へ回転することにより、その回転が中間ギヤ３９により減速されてメインギヤ３２に伝達される。これにより、弁軸１４及び各弁体１２，１３が、リターンスプリング３３の付勢力に抗して回動され、クーラ流路１７が開かれ、バイパス流路１８が閉じられる。また、各弁体１２，１３をある開度に保持するために、ＤＣモータ１６に通電により回転力を発生させることにより、その回転力がモータギヤ３８、中間ギヤ３９及びメインギヤ３２を介し保持力として弁軸１４及び各弁体１２，１３に伝達される。この保持力がリターンスプリング３３の付勢力に均衡することにより、各弁体１２，１３がそれぞれある中間開度に保持される。また、図２に示すように、クーラ弁体１２が全閉位置に配置されたときは、バイパス弁体１３が全開位置に配置され、ＥＧＲクーラを迂回した冷却されないＥＧＲガスがバイパス通路７及びバイパス流路１８を流れる。また、クーラ弁体１２が全開位置に配置されたときは、バイパス弁体１３が全閉位置に配置され、ＥＧＲクーラで冷却されたＥＧＲガスがクーラ通路６及びクーラ流路１７を流れる。この実施形態で、両弁体１２，１３はそれぞれ全閉位置と全開位置に切り替え配置されると共に、全閉位置と全開位置との間の任意の中間開度に配置可能となっている。このように両弁体１２，１３の開度を制御することにより、クーラ流路１７を通過するＥＧＲガス流量とバイパス流路１８を通過するＥＧＲガス流量をそれぞれ調節し、出口パイプ５から流れ出るＥＧＲガスの温度を任意に制御できるようになっている。 The bypass valve 1 is configured to control the flow of EGR gas in the flow paths 17 and 18 by rotating the valve shaft 14 to open and close the valve bodies 12 and 13. Therefore, as shown in FIG. 2, when the cooler valve body 12 is fully closed and the bypass valve body 13 is fully open, the DC motor 16 is energized and the motor gear 38 is rotated in one direction, so that the rotation is caused. It is decelerated by the intermediate gear 39 and transmitted to the main gear 32. As a result, the valve shaft 14 and the valve bodies 12 and 13 are rotated against the urging force of the return spring 33, the cooler flow path 17 is opened, and the bypass flow path 18 is closed. Further, in order to hold the valve bodies 12 and 13 at a certain opening degree, a rotational force is generated by energizing the DC motor 16, and the rotational force is used as a holding force via the motor gear 38, the intermediate gear 39 and the main gear 32. It is transmitted to the valve shaft 14 and the valve bodies 12 and 13, respectively. By balancing this holding force with the urging force of the return spring 33, the valve bodies 12 and 13 are held at a certain intermediate opening degree. Further, as shown in FIG. 2, when the cooler valve body 12 is arranged in the fully closed position, the bypass valve body 13 is arranged in the fully open position, and the uncooled EGR gas bypassing the EGR cooler is bypassed to the bypass passage 7 and the bypass. It flows through the flow path 18. When the cooler valve body 12 is arranged in the fully open position, the bypass valve body 13 is arranged in the fully closed position, and the EGR gas cooled by the EGR cooler flows through the cooler passage 6 and the cooler flow path 17. In this embodiment, the valve bodies 12 and 13 are switched between the fully closed position and the fully open position, respectively, and can be arranged at an arbitrary intermediate opening degree between the fully closed position and the fully open position, respectively. By controlling the opening degrees of both valve bodies 12 and 13 in this way, the EGR gas flow rate passing through the cooler flow path 17 and the EGR gas flow rate passing through the bypass flow path 18 are adjusted, respectively, and the EGR flowing out from the outlet pipe 5 is adjusted. The temperature of the gas can be controlled arbitrarily.

[バイパスバルブの技術的特徴について]
ここで、弁軸１４の第１軸端部１４ａは、メインギヤ３２等を含む減速機構１５を介してＤＣモータ１６に駆動連結されている。また、メインギヤ３２には、バルブ開度を検出するための開度センサ３１と対をなす磁石３４が固定される。そのため、開度センサ３１の検出精度を確保するためには、第１軸端部１４ａの回転を精密（リジッド）に支持する必要がある。また、各シール部材２６，２７は樹脂又はゴムを要素として構成されることから、各流路１７，１８を流れるＥＧＲガスによる熱害から各シール部材２６，２７を保護する必要がある。特に、バイパス流路１８には、ＥＧＲクーラで冷却されないより高温（最大７２０℃前後）のＥＧＲガスが流れることから、第２シール部材２７の熱害が特に問題になる。また、樹脂製のメインギヤ３２もＥＧＲガスによる熱害から保護する必要がある。そこで、この実施形態のバイパスバルブ１は、次のような技術的特徴を備える。 [Technical features of bypass valve]
Here, the first shaft end portion 14a of the valve shaft 14 is drive-connected to the DC motor 16 via a reduction mechanism 15 including a main gear 32 and the like. Further, a magnet 34 paired with an opening degree sensor 31 for detecting a valve opening degree is fixed to the main gear 32. Therefore, in order to ensure the detection accuracy of the opening degree sensor 31, it is necessary to precisely (rigidly) support the rotation of the first shaft end portion 14a. Further, since the sealing members 26 and 27 are composed of resin or rubber as an element, it is necessary to protect the sealing members 26 and 27 from heat damage caused by the EGR gas flowing through the flow paths 17 and 18. In particular, since EGR gas having a higher temperature (up to about 720 ° C.) that is not cooled by the EGR cooler flows through the bypass flow path 18, heat damage to the second seal member 27 becomes a particular problem. Further, the resin main gear 32 also needs to be protected from heat damage caused by EGR gas. Therefore, the bypass valve 1 of this embodiment has the following technical features.

すなわち、クーラ流路１７及びクーラ弁体１２は、第１軸端部１４ａに隣接して配置され、バイパス流路１８及びバイパス弁体１３は、第２軸端部１４ｂに隣接して配置される。また、転がり軸受２２は、第１軸端部１４ａの回転を精密に支持するために、高い精度と耐熱性を確保できるように構成される。ここで、転がり軸受２２は、第１軸端部１４ａに伝わる熱を本体ケーシング１９へ逃がすことはできるものの、その伝熱性は滑り軸受２３に比べて小さい。一方、滑り軸受２３は、第２軸端部１４ｂから本体ケーシング１９への放熱を促進できるように構成される。第２軸端部１４ｂには、バイパス流路１８を流れる冷却されないＥＧＲガスの熱が伝わるので、その熱を本体ケーシング１９へ円滑に逃がすために滑り軸受２３が使用される。加えて、滑り軸受２３の近傍にて本体ケーシング１９には、冷却水が流れる冷却水通路１９ｂが形成される。この冷却水通路１９ｂを流れる冷却水により、滑り軸受２３及び第２軸端部１４ｂを冷却するようになっている。 That is, the cooler flow path 17 and the cooler valve body 12 are arranged adjacent to the first shaft end portion 14a, and the bypass flow path 18 and the bypass valve body 13 are arranged adjacent to the second shaft end portion 14b. .. Further, the rolling bearing 22 is configured to ensure high accuracy and heat resistance in order to precisely support the rotation of the first shaft end portion 14a. Here, although the rolling bearing 22 can release the heat transferred to the first shaft end portion 14a to the main body casing 19, its heat transfer property is smaller than that of the slide bearing 23. On the other hand, the slide bearing 23 is configured to promote heat dissipation from the second shaft end portion 14b to the main body casing 19. Since the heat of the uncooled EGR gas flowing through the bypass flow path 18 is transmitted to the second shaft end portion 14b, the slide bearing 23 is used to smoothly dissipate the heat to the main body casing 19. In addition, a cooling water passage 19b through which cooling water flows is formed in the main body casing 19 in the vicinity of the slide bearing 23. The sliding bearing 23 and the second shaft end portion 14b are cooled by the cooling water flowing through the cooling water passage 19b.

また、第１シール部材２６よりも多くの熱を受ける第２シール部材２７の温度を低くするために、バイパス流路１８と滑り軸受２３と第２シール部材２７との配置や寸法の関係において、次のような関係が成立するように設定される。図３に、図２の一部であって、バイパス流路１８、バイパス弁体１３、第２シール部材２７、滑り軸受２３及び第２軸端部１４ｂの部分を拡大して断面図により示す。図２、図３に示すように、この実施形態では、バイパス流路１８と第２シール部材２７との間にて、第２軸端部１４ｂの外周には、同軸端部１４ｂの一部を縮径する括れ１４ｃが設けられる。 Further, in order to lower the temperature of the second seal member 27, which receives more heat than the first seal member 26, in terms of the arrangement and dimensions of the bypass flow path 18, the slide bearing 23, and the second seal member 27, The following relationships are set to hold. FIG. 3 is an enlarged cross-sectional view of a part of FIG. 2, the bypass flow path 18, the bypass valve body 13, the second seal member 27, the slide bearing 23, and the second shaft end portion 14b. As shown in FIGS. 2 and 3, in this embodiment, a part of the coaxial end portion 14b is provided on the outer circumference of the second shaft end portion 14b between the bypass flow path 18 and the second seal member 27. A constriction 14c for reducing the diameter is provided.

図３において、第２軸端部１４ｂは軸端面１４ｄを含む。滑り軸受２３は、その軸方向において第１端２３ａと第２端２３ｂを含む。第２シール部材２７は、バイパス弁体１３と滑り軸受２３との間にて滑り軸受２３の第１端２３ａに接して配置され、第２軸端部１４ｂと本体ケーシング１９との間をシールするために設けられる。第２シール部材２７は第２軸端部１４ｂと接する部分の軸方向において第１端２７ａと第２端２７ｂを含み、第２端２７ｂが滑り軸受２３の第１端２３ａと接する。ここで、弁軸１４の軸方向における距離であって、滑り軸受２３の第２端２３ｂから、バイパス流路１８において第２シール部材２７に最も近い壁面１８ａまでの距離を端面距離Ｌｅと定義する。また、第２シール部材２７の第１端２７ａから第２端２７ｂまでの距離をシール距離Ｌｓと定義する。更に、第２軸端部１４ｂの直径を軸径Ｄｓと定義し、括れ１４ｃの直径を括れ径Ｄｎと定義する。そして、弁軸１４の軸方向における距離であって、滑り軸受２３の軸方向における幅を軸受幅Ｗｂと定義すると、第２シール部材２７の温度を低くするために、軸受幅Ｗｂを以下の式（Ｆ２）の関係を満たすように設定した。
Ｗｂ＝Ａ＋Ｂ＊Ｌｅ−Ｃ＊Ｌｓ＋Ｅ＊Ｄｓ＋Ｆ＊Ｄｎ・・・（Ｆ２）
ここで、Ａ，Ｂ，Ｃ，Ｅ，Ｆは、所定の係数である。上記式（Ｆ２）は、軸受幅Ｗｂを従属変数とし、端面距離Ｌｅ、シール距離Ｌｓ及び軸径Ｄｓを独立変数とし、Ａ，Ｂ，Ｃ，Ｅ，Ｆを所定の係数として表した線形回帰モデルであって、所定の回帰分析により得られたものである。 In FIG. 3, the second shaft end portion 14b includes a shaft end surface 14d. The plain bearing 23 includes a first end 23a and a second end 23b in its axial direction. The second seal member 27 is arranged between the bypass valve body 13 and the slide bearing 23 in contact with the first end 23a of the slide bearing 23, and seals between the second shaft end portion 14b and the main body casing 19. Provided for. The second seal member 27 includes a first end 27a and a second end 27b in the axial direction of a portion in contact with the second shaft end portion 14b, and the second end 27b is in contact with the first end 23a of the slide bearing 23. Here, the distance in the axial direction of the valve shaft 14 from the second end 23b of the slide bearing 23 to the wall surface 18a closest to the second seal member 27 in the bypass flow path 18 is defined as the end face distance Le. .. Further, the distance from the first end 27a to the second end 27b of the second seal member 27 is defined as the seal distance Ls. Further, the diameter of the second shaft end portion 14b is defined as the shaft diameter Ds, and the diameter of the constriction 14c is defined as the constriction diameter Dn. If the axial distance of the valve shaft 14 and the axial width of the slide bearing 23 are defined as the bearing width Wb, the bearing width Wb is set to the following formula in order to lower the temperature of the second seal member 27. It was set to satisfy the relationship of (F2).
Wb = A + B * Le-C * Ls + E * Ds + F * Dn ... (F2)
Here, A, B, C, E, and F are predetermined coefficients. The above equation (F2) is a linear regression model in which the bearing width Wb is a dependent variable, the end face distance Le, the seal distance Ls, and the shaft diameter Ds are independent variables, and A, B, C, E, and F are expressed as predetermined coefficients. And it was obtained by a predetermined regression analysis.

ここで、軸受幅Ｗｂに対する第２シール部材２７の温度の関係を解析した結果を以下に説明する。この解析の前提条件は以下の通りである。図２に示すバイパスバルブ１を使用し、第２軸端部１４ｂのバイパス流路１８と接する端部の温度を「５００℃」に設定すると共に、冷却水通路１９ｂに「１０５℃」の温水を「毎分２.５リットル」流した。このとき使用した滑り軸受２３の径方向の厚みは「４.２６ｍｍ」であった。ここで、本体ケーシング１９の材質は「アルミ」であった。弁軸１４の材質は「ステンレス」であった。滑り軸受２３の材質は「銅焼結材」であった。第２シール部材２７の材質は「ＰＴＦＥ」あった。 Here, the result of analyzing the relationship between the temperature of the second seal member 27 and the bearing width Wb will be described below. The prerequisites for this analysis are as follows. Using the bypass valve 1 shown in FIG. 2, the temperature of the end of the second shaft end 14b in contact with the bypass flow path 18 is set to "500 ° C", and hot water of "105 ° C" is applied to the cooling water passage 19b. "2.5 liters per minute" was flushed. The radial thickness of the slide bearing 23 used at this time was "4.26 mm". Here, the material of the main body casing 19 was "aluminum". The material of the valve shaft 14 was "stainless steel". The material of the slide bearing 23 was "copper sintered material". The material of the second seal member 27 was "PTFE".

図４に、端面距離Ｌｅを「３０ｍｍ，４０ｍｍ，５０ｍｍ」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７の温度（シール温度）Ｔｃの関係をグラフにより示す。図４に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、端面距離Ｌｅが「３０ｍｍ」の場合は、軸受幅Ｗｂが「約６ｍｍ」となるときに、シール温度Ｔｃは「約２１５℃」で最も低くなる。端面距離Ｌｅが「４０ｍｍ」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約１８０℃」で最も低くなる。端面距離Ｌｅが「５０ｍｍ」の場合は、軸受幅Ｗｂが「約８.５ｍｍ」となるときに、シール温度Ｔｃは「約１６０℃」で最も低くなる。つまり、この場合は、端面距離Ｌｅが「３０ｍｍ，４０ｍｍ，５０ｍｍ」の間で大きくなるに連れて、最低のシール温度Ｔｃが「２１５℃〜１６０℃」の範囲で低くなり、最適な軸受幅Ｗｂが「６ｍｍ〜８.５ｍｍ」の範囲で大きくなることがわかる。 FIG. 4 graphically shows the relationship between the temperature (seal temperature) Tc of the second seal member 27 and the bearing width Wb when the end face distance Le is changed between “30 mm, 40 mm, and 50 mm”. As shown in FIG. 4, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the end face distance Le is "30 mm", the seal temperature Tc is the lowest at "about 215 ° C." when the bearing width Wb is "about 6 mm". When the end face distance Le is "40 mm", the seal temperature Tc is the lowest at "about 180 ° C." when the bearing width Wb is "about 7.5 mm". When the end face distance Le is "50 mm", the seal temperature Tc is the lowest at "about 160 ° C." when the bearing width Wb is "about 8.5 mm". That is, in this case, as the end face distance Le increases between "30 mm, 40 mm, and 50 mm", the minimum sealing temperature Tc decreases in the range of "215 ° C. to 160 ° C.", and the optimum bearing width Wb. Can be seen to increase in the range of "6 mm to 8.5 mm".

図５に、軸径Ｄｓを「φ４，φ８，φ１２」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。図５に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、軸径Ｄｓが「φ１２」の場合は、軸受幅Ｗｂが「約７ｍｍ」となるときに、シール温度Ｔｃは「約２３５℃」で最も低くなる。軸径Ｄｓが「φ８」の場合は、軸受幅Ｗｂが「約６.５ｍｍ」となるときに、シール温度Ｔｃは「約２１５℃」で最も低くなる。軸径Ｄｓが「φ４」の場合は、軸受幅Ｗｂが「約５.５ｍｍ」となるときに、シール温度Ｔｃは「約１９０℃」で最も低くなる。つまり、この場合は、軸径Ｄｓが「φ１２、φ８、φ４」の間で小さくなるに連れて、最低のシール温度Ｔｃが「２３５℃〜１９０℃」の範囲で低くなり、最適な軸受幅Ｗｂが「７ｍｍ〜５.５ｍｍ」の範囲で小さくなることがわかる。 FIG. 5 is a graph showing the relationship between the seal temperature Tc of the second seal member 27 and the bearing width Wb when the shaft diameter Ds is changed between “φ4, φ8, φ12”. As shown in FIG. 5, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the shaft diameter Ds is "φ12", the seal temperature Tc is the lowest at "about 235 ° C." when the bearing width Wb is "about 7 mm". When the shaft diameter Ds is "φ8", the seal temperature Tc is the lowest at "about 215 ° C." when the bearing width Wb is "about 6.5 mm". When the shaft diameter Ds is "φ4", the seal temperature Tc is the lowest at "about 190 ° C." when the bearing width Wb is "about 5.5 mm". That is, in this case, as the shaft diameter Ds becomes smaller between "φ12, φ8, φ4", the minimum sealing temperature Tc becomes lower in the range of "235 ° C. to 190 ° C.", and the optimum bearing width Wb. Can be seen to be smaller in the range of "7 mm to 5.5 mm".

図６に、シール距離Ｌｓを「１ｍｍ，３ｍｍ，５ｍｍ」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。図６に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、シール距離Ｌｓが「５ｍｍ」の場合は、軸受幅Ｗｂが「約６ｍｍ」となるときに、シール温度Ｔｃは「約２４０℃」で最も低くなる。シール距離Ｌｓが「３ｍｍ」の場合は、軸受幅Ｗｂが「約７ｍｍ」となるときに、シール温度Ｔｃは「約２１５℃」で最も低くなる。シール距離Ｌｓが「１ｍｍ」の場合は、軸受幅Ｗｂが「約８ｍｍ」となるときに、シール温度Ｔｃは「約１９０℃」で最も低くなる。つまり、この場合は、シール距離Ｌｓが「５ｍｍ，３ｍｍ，１ｍｍ」の間で小さくなるに連れて、最低のシール温度Ｔｃが「２４０℃〜１９０℃」の範囲で低くなり、最適な軸受幅Ｗｂが「６ｍｍ〜８ｍｍ」の範囲で大きくなることがわかる。 FIG. 6 graphically shows the relationship between the seal temperature Tc of the second seal member 27 and the bearing width Wb when the seal distance Ls is changed between “1 mm, 3 mm, and 5 mm”. As shown in FIG. 6, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the seal distance Ls is "5 mm", the seal temperature Tc is the lowest at "about 240 ° C." when the bearing width Wb is "about 6 mm". When the sealing distance Ls is "3 mm", the sealing temperature Tc is the lowest at "about 215 ° C." when the bearing width Wb is "about 7 mm". When the sealing distance Ls is "1 mm", the sealing temperature Tc is the lowest at "about 190 ° C." when the bearing width Wb is "about 8 mm". That is, in this case, as the sealing distance Ls becomes smaller between "5 mm, 3 mm, 1 mm", the minimum sealing temperature Tc becomes lower in the range of "240 ° C. to 190 ° C.", and the optimum bearing width Wb. Can be seen to increase in the range of "6 mm to 8 mm".

図７に、括れ径Ｄｎに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。ここで、前提条件は、端面距離Ｌｅが「３４.５ｍｍ」、シール距離Ｌｓが「５ｍｍ」、軸受幅Ｗｂが「７ｍｍ」である。軸径Ｄｓが「８ｍｍ」の第２軸端部１４ｂに対し、括れ径Ｄｎを「５.５ｍｍ〜８.０ｍｍ」の範囲で増加させた場合のシール温度Ｔｃの変化を示す。このグラフから、括れ径Ｄｎが小さくなるほどシール温度Ｔｃが低くなることがわかる。例えば、括れ径Ｄｎを「６ｍｍ」とした場合は、括れ１４ｃがない場合（括れ径Ｄｎが「８ｍｍ」）の場合と比べて「３７℃」の温度低減効果があることがわかる。 FIG. 7 is a graph showing the relationship between the sealing temperature Tc of the second sealing member 27 and the constriction diameter Dn. Here, the preconditions are that the end face distance Le is "34.5 mm", the seal distance Ls is "5 mm", and the bearing width Wb is "7 mm". The change in the seal temperature Tc when the constriction diameter Dn is increased in the range of "5.5 mm to 8.0 mm" with respect to the second shaft end portion 14b having the shaft diameter Ds of "8 mm" is shown. From this graph, it can be seen that the seal temperature Tc decreases as the constriction diameter Dn decreases. For example, when the constriction diameter Dn is set to "6 mm", it can be seen that there is a temperature reduction effect of "37 ° C." as compared with the case where there is no constriction 14c (constriction diameter Dn is "8 mm").

図８に、熱源（バイパス流路１８の壁面）からの距離に対する弁軸１４（第２軸端部１４ｂ）の温度（弁軸温度）との関係をグラフにより示す。直線Ａ１，Ａ２は、端面距離Ｌｅを相対的に長くした場合の熱源からの距離変化に対する弁軸温度の変化を示す。直線（実線）Ａ１は、軸受幅Ｗｂが相対的に小さい場合を示し、直線（破線）Ａ２は、軸受幅Ｗｂが相対的に大きい場合を示す。二つの直線Ａ１，Ａ２の比較からわかるように、軸受幅Ｗｂが相対的に大きい場合（直線Ａ２）は、軸受幅Ｗｂが相対的に小さい場合（直線Ａ１）に比べて、熱源からの距離が相対的に短くてもシール温度Ｔｃが相対的に低くなることがわかる。すなわち、軸受幅Ｗｂを大きくすれば、シール温度Ｔｃが相対的に低くなることがわかる。これに対し、図８の直線Ｂ１，Ｂ２は、端面距離Ｌｅを相対的に短くした場合の熱源からの距離変化に対する弁軸温度の変化を示す。直線（実線）Ｂ１は、軸受幅Ｗｂが相対的に小さい場合を示し、直線（破線）Ｂ２は、軸受幅Ｗｂが相対的に大きい場合を示す。二つの直線Ｂ１，Ｂ２の比較からわかるように、軸受幅Ｗｂが相対的に大きい場合（直線Ｂ２）は、軸受幅Ｗｂが相対的に小さい場合（直線Ｂ１）に比べて、熱源からの距離が相対的に短ければシール温度Ｔｃは相対的に低くならないことがわかる。すなわち、端面距離Ｌｅが小さい場合は大きい場合に比べて温度勾配が大きくなり、軸受幅Ｗｂが大きくてもシール温度Ｔｃが相対的に低くならない。従って、端面距離Ｌｅ、軸受幅Ｗｂ、シール距離Ｌｓ及び軸径Ｄｓの関係から、シール温度Ｔｃを低くできる最適な軸受幅Ｗｂが問題となる。 FIG. 8 graphically shows the relationship between the distance from the heat source (the wall surface of the bypass flow path 18) and the temperature (valve shaft temperature) of the valve shaft 14 (second shaft end 14b). The straight lines A1 and A2 show the change in the valve shaft temperature with respect to the change in the distance from the heat source when the end face distance Le is relatively long. The straight line (solid line) A1 indicates a case where the bearing width Wb is relatively small, and the straight line (broken line) A2 indicates a case where the bearing width Wb is relatively large. As can be seen from the comparison of the two straight lines A1 and A2, when the bearing width Wb is relatively large (straight line A2), the distance from the heat source is larger than when the bearing width Wb is relatively small (straight line A1). It can be seen that the seal temperature Tc is relatively low even if it is relatively short. That is, it can be seen that if the bearing width Wb is increased, the seal temperature Tc becomes relatively low. On the other hand, the straight lines B1 and B2 in FIG. 8 show the change in the valve shaft temperature with respect to the change in the distance from the heat source when the end face distance Le is relatively short. The straight line (solid line) B1 indicates a case where the bearing width Wb is relatively small, and the straight line (broken line) B2 indicates a case where the bearing width Wb is relatively large. As can be seen from the comparison of the two straight lines B1 and B2, when the bearing width Wb is relatively large (straight line B2), the distance from the heat source is larger than when the bearing width Wb is relatively small (straight line B1). It can be seen that if it is relatively short, the seal temperature Tc does not become relatively low. That is, when the end face distance Le is small, the temperature gradient becomes larger than when it is large, and even if the bearing width Wb is large, the seal temperature Tc does not become relatively low. Therefore, from the relationship between the end face distance Le, the bearing width Wb, the seal distance Ls, and the shaft diameter Ds, the optimum bearing width Wb capable of lowering the seal temperature Tc becomes a problem.

そこで、本願出願人は、上記した各種パラメータの関係について回帰分析をすることにより、第２シール部材２７の温度を低くするために、軸受幅Ｗｂを以下の式（Ｆ２）の関係を満たすように設定することができた。
Ｗｂ＝Ａ＋Ｂ＊Ｌｅ−Ｃ＊Ｌｓ＋Ｅ＊Ｄｓ＋Ｆ＊Ｄｎ・・・（Ｆ２）
ここで、Ａ，Ｂ，Ｃ，Ｅ，Ｆは所定の係数である。係数Ａは、一例として「１.４２６」であり、その標準誤差は「０.５３１」である。係数Ｂは、一例として「０.０８３６６」であり、その標準誤差は「０.００７」である。係数Ｃは、一例として「０.３１９２」であり、その標準誤差は「０.０５５」である。係数Ｅは、一例として「０.２９０２」であり、その標準誤差は「０.０２８」である。係数Ｆは、一例として「０.２２１６」であり、その標準誤差は「０.０５２」である。ここで、係数ＢはＡの約１／１４であり、係数Ｃは係数Ｂの約４倍であり、係数Ｅは係数Ｃの約０.９倍であり、係数Ｆは係数Ｅの約０.７６倍である。係数Ａ以外の係数Ｂ，Ｃ，Ｅ，Ｆの中の重みとしては、係数Ｃ，Ｅが相対的に大きく、シール距離Ｌｓと軸径Ｄｓの軸受幅Ｗｂへの影響が大きいと考えられる。これら係数Ａ，Ｂ，Ｃ，Ｅ，Ｆの数値より、式（Ｆ２）を次のような式（Ｆ２Ａ）に書き換えることができる。
Ｗｂ＝1.426＋0.08366＊Ｌｅ−0.3192＊Ｌｓ＋0.2902＊Ｄｓ＋0.2216＊Ｄｎ・・・（Ｆ２Ａ） Therefore, the applicant of the present application performs a regression analysis on the relationship between the various parameters described above so that the bearing width Wb satisfies the relationship of the following equation (F2) in order to lower the temperature of the second seal member 27. I was able to set it.
Wb = A + B * Le-C * Ls + E * Ds + F * Dn ... (F2)
Here, A, B, C, E, and F are predetermined coefficients. The coefficient A is "1.426" as an example, and its standard error is "0.531". The coefficient B is, for example, "0.083666", and its standard error is "0.007". The coefficient C is "0.3192" as an example, and its standard error is "0.055". The coefficient E is "0.2902" as an example, and its standard error is "0.028". The coefficient F is "0.2216" as an example, and its standard error is "0.052". Here, the coefficient B is about 1/14 of A, the coefficient C is about 4 times the coefficient B, the coefficient E is about 0.9 times the coefficient C, and the coefficient F is about 0. It is 76 times. As the weights in the coefficients B, C, E, and F other than the coefficient A, the coefficients C and E are relatively large, and it is considered that the sealing distance Ls and the shaft diameter Ds have a large influence on the bearing width Wb. From the numerical values of these coefficients A, B, C, E, and F, the equation (F2) can be rewritten into the following equation (F2A).
Wb = 1.426 + 0.08366 * Le-0.3192 * Ls + 0.2902 * Ds + 0.2216 * Dn ・・・ (F2A)

ここで、シール温度Ｔｃを低くできる最適な軸受幅Ｗｂに対する端面距離Ｌｅ、シール距離Ｌｓ、軸径Ｄｓ、括れ１４ｃの径（括れ径）Ｄｎの影響について説明する。図９に、式（Ｆ２Ａ）によって得られた各種パラメータの関係を表により示す。端面距離Ｌｅは「３０ｍｍ，４０ｍｍ，５０ｍｍ」の間で変化し、シール距離Ｌｓは「１ｍｍ，３ｍｍ，５ｍｍ」の間で変化し、軸径Ｄｓは「８ｍｍ，１２ｍｍ」の間で変化し、括れ径Ｄｎは「６ｍｍ，８ｍｍ」の間で変化する。これらの組み合わせによって、「６.０３ｍｍ〜８.５２ｍｍ」の間で最適な軸受幅Ｗｂを得ることができた。 Here, the effects of the end face distance Le, the seal distance Ls, the shaft diameter Ds, and the diameter (constriction diameter) Dn of the constriction 14c on the optimum bearing width Wb that can lower the seal temperature Tc will be described. FIG. 9 shows the relationship of various parameters obtained by the formula (F2A) in a table. The end face distance Le changes between "30 mm, 40 mm, 50 mm", the seal distance Ls changes between "1 mm, 3 mm, 5 mm", and the shaft diameter Ds changes between "8 mm, 12 mm". The diameter Dn varies between "6 mm, 8 mm". By these combinations, the optimum bearing width Wb could be obtained between "6.03 mm and 8.52 mm".

最適な軸受幅Ｗｂは、一例として、次のような手順で決定することができる。すなわち、先ず、第２軸端部１４ｂのバイパス流路１８に最も近い端部の温度を設定（予測）する。次に、軸径Ｄｓ、括れ径Ｄｎ、シール距離Ｌｓを予め任意に決定する。これにより、軸受幅Ｗｂと端面距離Ｌｅとの対応関係が出る。次に、第２シール部材２７の温度が要件を満たす範囲で、最小の端面距離Ｌｅを決定する。このときの軸受幅を、最適な軸受幅Ｗｂとして決定する。 The optimum bearing width Wb can be determined, for example, by the following procedure. That is, first, the temperature of the end portion of the second shaft end portion 14b closest to the bypass flow path 18 is set (predicted). Next, the shaft diameter Ds, the constriction diameter Dn, and the seal distance Ls are arbitrarily determined in advance. As a result, the correspondence between the bearing width Wb and the end face distance Le is obtained. Next, the minimum end face distance Le is determined within the range where the temperature of the second seal member 27 satisfies the requirement. The bearing width at this time is determined as the optimum bearing width Wb.

ここで、例えば、図６のグラフから、最適な軸受幅Ｗｂｂを矢印で示す範囲に求めることができる。この最適な軸受幅Ｗｂｂの範囲は、中央値に対し「±１ｍｍ」の範囲を有し、シール温度Ｔｃの最低温度に対し「±５℃」の範囲を有する。図１０に、第２シール部材２７のシール温度Ｔｃと寿命（耐久性）の関係をグラフにより示す。このグラフから、シール温度Ｔｃが所定値Ｔ１となる場合の寿命を所定値α２とすると、所定値Ｔ１−５（℃）の場合の寿命は所定値α１（＜α２）となり、所定値Ｔ１＋５（℃）の場合の寿命は所定値α３（＞α２）となることがわかる。このように軸受幅Ｗｂの最適化によってシール温度Ｔｃが「５℃」変わるだけで、シール部材２７の寿命が倍増又は半減するほどの効果があることがわかる。 Here, for example, from the graph of FIG. 6, the optimum bearing width Wbb can be obtained in the range indicated by the arrow. The range of the optimum bearing width Wbb has a range of "± 1 mm" with respect to the median value and a range of "± 5 ° C." with respect to the minimum temperature of the seal temperature Tc. FIG. 10 is a graph showing the relationship between the seal temperature Tc of the second seal member 27 and the life (durability). From this graph, assuming that the life when the seal temperature Tc is the predetermined value T1 is the predetermined value α2, the life when the seal temperature Tc is the predetermined value T1-5 (° C.) is the predetermined value α1 (<α2) and the predetermined value T1 + 5 (° C. It can be seen that the life in the case of) is a predetermined value α3 (> α2). As described above, it can be seen that the optimization of the bearing width Wb has the effect of doubling or halving the life of the seal member 27 only by changing the seal temperature Tc by "5 ° C.".

以上説明したように、この実施形態のバイパスバルブ１によれば、所定の前提条件下で、軸受幅Ｗｂ、端面距離Ｌｅ、シール距離Ｌｓ、軸径Ｄｓ、括れ径Ｄｎの関係を式（Ｆ２）の関係を満たすように設定することにより、第２シール部材２７の温度を低くすることができ、第２シール部材２７の寿命を伸ばすことができる。すなわち、バイパス流路１８と滑り軸受２３と第２シール部材２７との配置や寸法の関係において、滑り軸受２２の軸受幅Ｗｂを上記のように設定することで、第２シール部材２７の耐熱性を有効に向上させることができる。 As described above, according to the bypass valve 1 of this embodiment, the relationship between the bearing width Wb, the end face distance Le, the seal distance Ls, the shaft diameter Ds, and the constriction diameter Dn is expressed by the equation (F2) under predetermined preconditions. By setting so as to satisfy the above relationship, the temperature of the second seal member 27 can be lowered, and the life of the second seal member 27 can be extended. That is, by setting the bearing width Wb of the slide bearing 22 as described above in relation to the arrangement and dimensions of the bypass flow path 18, the slide bearing 23, and the second seal member 27, the heat resistance of the second seal member 27 is reduced. Can be effectively improved.

ここで、端面距離Ｌｅは、バイパスバルブ１の小型化要請によってある所定値に決められる。従って、端面距離Ｌｅを固定すると、第２シール部材２７のシール温度Ｔｃは、バイパス流路１８を流れるＥＧＲガスの熱量によって変わり得る。例えば、このシール温度Ｔｃは、軸受幅Ｗｂが大きくなるほど第２シール部材２７がバイパス流路１８に近付くことから高くなり、軸受幅Ｗｂが小さくなるほど第２シール部材２７がバイパス流路１８から遠ざかることから温度が低くなる。その反面、軸受幅Ｗｂが大きくなるほど第２軸端部１４ｂから本体ケーシング１９への放熱量が多くなり、その分だけ第２シール部材２７に伝わる熱が少なくなる。また、第２シール部材２７は、そのシール距離Ｌｓが小さくなるほど温度が高くなる。この実施形態では、これらの相乗作用を考慮して、第２シール部材２７のシール温度Ｔｃを低くできる最適な軸受幅Ｗｂを求めることができる。 Here, the end face distance Le is determined to a predetermined value in response to a request for miniaturization of the bypass valve 1. Therefore, when the end face distance Le is fixed, the seal temperature Tc of the second seal member 27 can change depending on the amount of heat of the EGR gas flowing through the bypass flow path 18. For example, the seal temperature Tc increases as the bearing width Wb increases because the second seal member 27 approaches the bypass flow path 18, and the second seal member 27 moves away from the bypass flow path 18 as the bearing width Wb decreases. The temperature drops from. On the other hand, as the bearing width Wb increases, the amount of heat radiated from the second shaft end portion 14b to the main body casing 19 increases, and the heat transferred to the second seal member 27 decreases accordingly. Further, the temperature of the second seal member 27 increases as the seal distance Ls decreases. In this embodiment, the optimum bearing width Wb capable of lowering the seal temperature Tc of the second seal member 27 can be obtained in consideration of these synergistic actions.

＜第２実施形態＞
次に、排気制御弁をＥＧＲクーラユニットに使用されるバイパスバルブに具体化した第２実施形態につき図面を参照して詳細に説明する。 <Second Embodiment>
Next, a second embodiment in which the exhaust control valve is embodied as a bypass valve used in the EGR cooler unit will be described in detail with reference to the drawings.

図１１に、バイパス流路１８、バイパス弁体１３、第２シール部材２７、滑り軸受２３及び第２軸端部１４ｂの部分を拡大して図３に準ずる断面図により示す。この実施形態では、第２軸端部１４ｂから括れ１４ｃを省略した点で第１実施形態と異なる。 FIG. 11 shows an enlarged cross-sectional view of the bypass flow path 18, the bypass valve body 13, the second seal member 27, the slide bearing 23, and the second shaft end portion 14b according to FIG. This embodiment is different from the first embodiment in that the constriction 14c is omitted from the second shaft end portion 14b.

図１２に、端面距離Ｌｅを「３０ｍｍ，４０ｍｍ，５０ｍｍ」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。図１２に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、端面距離Ｌｅが「３０ｍｍ」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２４５℃」で最も低くなる。端面距離Ｌｅが「４０ｍｍ」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２１０℃」で最も低くなる。端面距離Ｌｅが「５０ｍｍ」の場合は、軸受幅Ｗｂが「約８ｍｍ」となるときに、シール温度Ｔｃは「約１８５℃」で最も低くなる。つまり、この場合は、端面距離Ｌｅが「３０ｍｍ，４０ｍｍ，５０ｍｍ」の範囲で大きくなるに連れて、最低のシール温度Ｔｃが「２４５℃〜１８５℃」の範囲で低くなり、最適な軸受幅Ｗｂが「７.５ｍｍ〜８ｍｍ」の範囲で大きくなることがわかる。 FIG. 12 is a graph showing the relationship between the seal temperature Tc of the second seal member 27 and the bearing width Wb when the end face distance Le is changed between “30 mm, 40 mm, and 50 mm”. As shown in FIG. 12, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the end face distance Le is "30 mm", the seal temperature Tc is the lowest at "about 245 ° C." when the bearing width Wb is "about 7.5 mm". When the end face distance Le is "40 mm", the seal temperature Tc is the lowest at "about 210 ° C." when the bearing width Wb is "about 7.5 mm". When the end face distance Le is "50 mm", the seal temperature Tc is the lowest at "about 185 ° C." when the bearing width Wb is "about 8 mm". That is, in this case, as the end face distance Le increases in the range of "30 mm, 40 mm, 50 mm", the minimum sealing temperature Tc decreases in the range of "245 ° C to 185 ° C", and the optimum bearing width Wb Can be seen to increase in the range of "7.5 mm to 8 mm".

図１３に、軸径Ｄｓを「φ４，φ８，φ１２」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。図１３に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、軸径Ｄｓが「φ１２」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２６５℃」で最も低くなる。軸径Ｄｓが「φ８」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２４５℃」で最も低くなる。軸径Ｄｓが「φ４」の場合は、軸受幅Ｗｂが「約５.５ｍｍ」となるときに、シール温度Ｔｃは「約２１５℃」で最も低くなる。つまり、この場合は、軸径Ｄｓが「φ１２，φ８，φ４」の範囲で小さくなるに連れて、最低のシール温度Ｔｃが「２６５℃〜２１５℃」の範囲で低くなり、最適な軸受幅Ｗｂが「７.５ｍｍ〜５.５ｍｍ」の範囲で小さくなることがわかる。 FIG. 13 is a graph showing the relationship between the seal temperature Tc of the second seal member 27 and the bearing width Wb when the shaft diameter Ds is changed between “φ4, φ8, φ12”. As shown in FIG. 13, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the shaft diameter Ds is "φ12", the seal temperature Tc is the lowest at "about 265 ° C." when the bearing width Wb is "about 7.5 mm". When the shaft diameter Ds is "φ8", the seal temperature Tc is the lowest at "about 245 ° C." when the bearing width Wb is "about 7.5 mm". When the shaft diameter Ds is "φ4", the seal temperature Tc is the lowest at "about 215 ° C." when the bearing width Wb is "about 5.5 mm". That is, in this case, as the shaft diameter Ds decreases in the range of "φ12, φ8, φ4", the minimum seal temperature Tc decreases in the range of "265 ° C to 215 ° C", and the optimum bearing width Wb Can be seen to be smaller in the range of "7.5 mm to 5.5 mm".

図１４に、シール距離Ｌｓを「１ｍｍ，３ｍｍ，５ｍｍ」の間で変えた場合の軸受幅Ｗｂに対する第２シール部材２７のシール温度Ｔｃの関係をグラフにより示す。図１４に示すように、シール温度Ｔｃは、軸受幅Ｗｂを「３ｍｍ〜１５ｍｍ」の間で変化させることで二次曲線的に変化する。ここで、シール距離Ｌｓが「５ｍｍ」の場合は、軸受幅Ｗｂが「約５.５ｍｍ」となるときに、シール温度Ｔｃは「約２６５℃」で最も低くなる。シール距離Ｌｓが「３ｍｍ」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２４５℃」で最も低くなる。シール距離Ｌｓが「１ｍｍ」の場合は、軸受幅Ｗｂが「約７.５ｍｍ」となるときに、シール温度Ｔｃは「約２１５℃」で最も低くなる。つまり、この場合は、シール距離Ｌｓが「５ｍｍ，３ｍｍ，１ｍｍ」の範囲で小さくなるに連れて、最低のシール温度Ｔｃが「２６５℃〜２１５℃」の範囲で低くなり、最適な軸受幅Ｗｂが「５.５ｍｍ〜７.５ｍｍ」の範囲で大きくなることがわかる。 FIG. 14 is a graph showing the relationship between the seal temperature Tc of the second seal member 27 and the bearing width Wb when the seal distance Ls is changed between “1 mm, 3 mm, and 5 mm”. As shown in FIG. 14, the seal temperature Tc changes in a quadratic curve by changing the bearing width Wb between “3 mm to 15 mm”. Here, when the seal distance Ls is "5 mm", the seal temperature Tc is the lowest at "about 265 ° C." when the bearing width Wb is "about 5.5 mm". When the sealing distance Ls is "3 mm", the sealing temperature Tc is the lowest at "about 245 ° C." when the bearing width Wb is "about 7.5 mm". When the sealing distance Ls is "1 mm", the sealing temperature Tc is the lowest at "about 215 ° C." when the bearing width Wb is "about 7.5 mm". That is, in this case, as the seal distance Ls decreases in the range of "5 mm, 3 mm, 1 mm", the minimum seal temperature Tc decreases in the range of "265 ° C to 215 ° C", and the optimum bearing width Wb Can be seen to increase in the range of "5.5 mm to 7.5 mm".

そこで、この実施形態では、第２軸端部１４ｂに括れ１４ｃがない場合において、本願出願人は、上記した各種パラメータの関係につき回帰分析をすることにより、第２シール部材２７のシール温度Ｔｃを低くするために、軸受幅Ｗｂを以下の式（Ｆ１）の関係を満たすように設定することができた。
Ｗｂ＝Ａ＋Ｂ＊Ｌｅ−Ｃ＊Ｌｓ＋（Ｅ＋Ｆ）＊Ｄｓ・・・（Ｆ１）
ここで、Ａ，Ｂ，Ｃ，Ｅ，Ｆは所定の係数である。係数Ａは、一例として「１.４２６」であり、その標準誤差は「０.５３１」である。係数Ｂは、一例として「０.０８３６６」であり、その標準誤差は「０.００７」である。係数Ｃは、一例として「０.３１９２」であり、その標準誤差は「０.０５５」である。係数Ｅは、一例として「０.２９０２」であり、その標準誤差は「０.０２８」である。係数Ｆは、一例として「０.２２１６」であり、その標準誤差は「０.０５２」である。ここで、係数ＢはＡの約１／１４であり、係数Ｃは係数Ｂの約４倍であり、係数Ｅは係数Ｃの約０.９倍であり、係数Ｆは係数Ｅの約０.７６倍である。これら係数Ａ，Ｂ，Ｃ，Ｅ，Ｆの数値より、式（Ｆ１）を次のような式（Ｆ１Ａ）に書き換えることができる。
Ｗｂ＝1.426＋0.08366＊Ｌｅ−0.3192＊Ｌｓ＋0.5118＊Ｄｓ・・・（Ｆ１Ａ） Therefore, in this embodiment, when the second shaft end portion 14b does not have a constriction 14c, the applicant of the present application performs a regression analysis on the relationship of the various parameters described above to determine the seal temperature Tc of the second seal member 27. In order to lower the bearing width Wb, the bearing width Wb could be set so as to satisfy the relationship of the following equation (F1).
Wb = A + B * Le-C * Ls + (E + F) * Ds ... (F1)
Here, A, B, C, E, and F are predetermined coefficients. The coefficient A is "1.426" as an example, and its standard error is "0.531". The coefficient B is, for example, "0.083666", and its standard error is "0.007". The coefficient C is "0.3192" as an example, and its standard error is "0.055". The coefficient E is "0.2902" as an example, and its standard error is "0.028". The coefficient F is "0.2216" as an example, and its standard error is "0.052". Here, the coefficient B is about 1/14 of A, the coefficient C is about 4 times the coefficient B, the coefficient E is about 0.9 times the coefficient C, and the coefficient F is about 0. It is 76 times. From the numerical values of these coefficients A, B, C, E, and F, the equation (F1) can be rewritten into the following equation (F1A).
Wb = 1.426 + 0.08366 * Le-0.3192 * Ls + 0.5118 * Ds ... (F1A)

以上説明したように、この実施形態のバイパスバルブ１でも、所定の前提条件下で、軸受幅Ｗｂ、端面距離Ｌｅ、シール距離Ｌｓ、軸径Ｄｓの関係を式（Ｆ１）の関係を満たすように設定することにより、第２シール部材２７の温度を低くすることができ、第２シール部材２７の寿命を伸ばすことができる。すなわち、バイパス流路１８と滑り軸受２３と第２シール部材２７との配置や寸法の関係において、滑り軸受２２の軸受幅Ｗｂを上記のように設定することで、第２シール部材２７の耐熱性を有効に向上させることができる。 As described above, also in the bypass valve 1 of this embodiment, the relationship between the bearing width Wb, the end face distance Le, the seal distance Ls, and the shaft diameter Ds is satisfied with the relationship of the equation (F1) under predetermined preconditions. By setting, the temperature of the second seal member 27 can be lowered, and the life of the second seal member 27 can be extended. That is, by setting the bearing width Wb of the slide bearing 22 as described above in relation to the arrangement and dimensions of the bypass flow path 18, the slide bearing 23, and the second seal member 27, the heat resistance of the second seal member 27 is reduced. Can be effectively improved.

なお、この開示技術は前記各実施形態に限定されるものではなく、開示技術の趣旨を逸脱することのない範囲で構成の一部を適宜変更して実施することもできる。 It should be noted that this disclosure technique is not limited to each of the above-described embodiments, and a part of the configuration may be appropriately modified and implemented within a range that does not deviate from the purpose of the disclosure technique.

（１）前記各実施形態では、排気制御弁を特定構造のバイパスバルブ１に具体化したが、その他の構造のバイパスバルブに具体化することもできる。この場合、上記した各種パラメータＷｂ，Ｌｅ，Ｌｓ，Ｄｓの関係を上記した式（Ｆ１）又は式（Ｆ２）の関係で設定することができる。 (1) In each of the above embodiments, the exhaust control valve is embodied in a bypass valve 1 having a specific structure, but it can also be embodied in a bypass valve having another structure. In this case, the relationship between the various parameters Wb, Le, Ls, and Ds described above can be set by the relationship of the equation (F1) or the equation (F2) described above.

（２）前記各実施形態では、一対の軸受２２，２３のうち、一方が転がり軸受２２で他方が滑り軸受２３で構成されたバイパスバルブ１に具体化したが、一対の軸受の両方が滑り軸受で構成されるバイパスバルブに具体化することもできる。 (2) In each of the above embodiments, of the pair of bearings 22 and 23, one is embodied as a bypass valve 1 composed of a rolling bearing 22 and the other a sliding bearing 23, but both of the pair of bearings are sliding bearings. It can also be embodied in a bypass valve composed of.

この開示技術は、エンジンの排気系に設けられる各種排気制御弁に利用することができる。 This disclosed technology can be used for various exhaust control valves provided in the exhaust system of an engine.

１バイパスバルブ
１１バルブケーシング
１３バイパス弁体
１４弁軸
１４ｂ第２軸端部
１４ｃ括れ
１８バイパス流路
１８ａ最も近い壁面
１９本体ケーシング
２３滑り軸受
２３ａ第１端
２３ｂ第２端
２７第２シール部材
２７ａ第１端
２７ｂ第２端
Ｌｅ端面距離
Ｌｓシール距離
Ｄｓ軸径
Ｄｎ括れ径
Ｗｂ軸受幅
Ｗｂｂ最適な軸受幅
Ｔｃシール温度 1 Bypass valve 11 Valve casing 13 Bypass valve body 14 Valve shaft 14b 2nd shaft end 14c Constriction 18 Bypass flow path 18a Nearest wall surface 19 Main body casing 23 Slide bearing 23a 1st end 23b 2nd end 27 2nd seal member 27a 1st end 27b 2nd end Le End face distance Ls Sealing distance Ds Shaft diameter Dn Constriction diameter Wb Bearing width Wbb Optimal bearing width Tc Sealing temperature

Claims

With the casing including the exhaust flow path,
A valve shaft arranged in the casing through the flow path,
The valve shaft includes the shaft end and
A valve body arranged in the flow path and integrally provided with the valve shaft,
A slide bearing provided at the end of the shaft to rotatably support the valve shaft with respect to the casing.
The plain bearing includes the first end and the second end in the axial direction thereof.
A sealing member arranged between the valve body and the slide bearing in contact with the first end of the slide bearing and for sealing between the shaft end and the casing.
The seal member includes a first end and a second end in the axial direction of a portion in contact with the shaft end portion, the second end is in contact with the first end of the slide bearing, and the valve shaft is rotated. In an exhaust control valve configured to control the flow of the exhaust in the flow path by opening and closing the valve body.
The distance in the axial direction of the valve shaft from the second end of the slide bearing to the wall surface closest to the seal member in the flow path is defined as the end face distance (Le).
The distance from the first end to the second end of the seal member is defined as the seal distance (Ls).
The diameter of the shaft end is defined as the shaft diameter (Ds).
The axial distance of the valve shaft, and the axial width of the slide bearing, is defined as the bearing width (Wb).
Wb = A + B * Le-C * Ls + (E + F) * Ds ... (F1) in which the bearing width (Wb) is set so as to satisfy the following formula (F1) in order to lower the temperature of the sealing member.
A, B, C, E, F: Predetermined coefficient
Wb ≤ Le-Ls
Exhaust control valve characterized by that.

With the casing including the exhaust flow path,
A valve shaft arranged in the casing through the flow path,
The valve shaft includes the shaft end and
A valve body arranged in the flow path and integrally provided with the valve shaft,
A slide bearing provided at the end of the shaft to rotatably support the valve shaft with respect to the casing.
The plain bearing includes the first end and the second end in the axial direction thereof.
A sealing member arranged between the valve body and the slide bearing in contact with the first end of the slide bearing and for sealing between the shaft end and the casing.
The seal member includes a first end and a second end in the axial direction of a portion in contact with the shaft end portion, the second end is in contact with the first end of the slide bearing, and the valve shaft is rotated. In an exhaust control valve configured to control the flow of the exhaust in the flow path by opening and closing the valve body.
The distance in the axial direction of the valve shaft from the second end of the slide bearing to the wall surface closest to the seal member in the flow path is defined as the end face distance (Le).
The distance from the first end to the second end of the seal member is defined as the seal distance (Ls).
The diameter of the shaft end is defined as the shaft diameter (Ds).
A constriction is provided on the outer circumference of the shaft end portion between the flow path and the seal member.
The diameter of the constriction is defined as the constriction diameter (Dn).
The axial distance of the valve shaft, and the axial width of the slide bearing, is defined as the bearing width (Wb).
Wb = A + B * Le-C * Ls + E * Ds + F * Dn ... (F2) in which the bearing width (Wb) is set to satisfy the following formula (F2) in order to lower the temperature of the sealing member.
A, B, C, E, F: Predetermined coefficient
Wb ≤ Le-Ls
Exhaust control valve characterized by that.