JP6210771B2

JP6210771B2 - Steering boots

Info

Publication number: JP6210771B2
Application number: JP2013151832A
Authority: JP
Inventors: 充永田; 正章芹澤
Original assignee: キーパー株式会社
Priority date: 2013-07-22
Filing date: 2013-07-22
Publication date: 2017-10-11
Anticipated expiration: 2033-07-22
Also published as: JP2015021589A

Description

本発明は、自動車のステアリング装置内部への水や塵埃等の浸入を防止するために、ステアリング装置のハウジングとタイロッドとの間に装着されるステアリングブーツに関する。さらに詳述すると、本発明は、ステアリングブーツの大径側ブーツ取付部の固定構造の改良に関するものである。 The present invention relates to a steering boot mounted between a housing of a steering device and a tie rod in order to prevent water, dust, and the like from entering the inside of the steering device of an automobile. More specifically, the present invention relates to an improvement in the fixing structure of the large-diameter side boot mounting portion of the steering boot.

従来のステアリングブーツは、蛇腹部の両端の大径側ブーツ取付部と小径側ブーツ取付部とをステアリング装置のハウジングとタイロッドとにそれぞれ嵌め込んで、ブーツバンドのみで各ブーツ取付部を締め付けることにより固定されている。つまり、従来のステアリングブーツでは、図５に示すように、ブーツ取付部１０１と相手側部材１０２との接触部（本明細書では「シール部」と呼ぶ）１０３のみでシールを行なっている。 In conventional steering boots, the large-diameter boot mounting part and the small-diameter boot mounting part at both ends of the bellows part are fitted into the steering device housing and the tie rod, respectively, and each boot mounting part is tightened only by the boot band. It is fixed. That is, in the conventional steering boot, as shown in FIG. 5, sealing is performed only at the contact portion 103 (referred to as “seal portion” in this specification) between the boot mounting portion 101 and the counterpart member 102.

一方、樹脂製ステアリングブーツの場合、ダイレクトブロー成形やプレスブロー成形などの、ブーツ内周面を形成するための金型が無い工法において成形され、ブーツ外周面が金型面で成形されている。 On the other hand, in the case of a resin steering boot, it is molded by a method without a mold for forming the inner peripheral surface of the boot, such as direct blow molding or press blow molding, and the outer peripheral surface of the boot is molded with the mold surface.

特開２００８−５７７８９号公報JP 2008-57789 A

このようにシール部１０３のみでシールを行っている従来のステアリングブーツによれば、海岸付近を長期間走行する厳しい環境下では、取り付け相手であるステアリング装置のハウジング１０２の腐食の進行に伴い、徐々にシール部１０３を損傷して行くことで、最終的にシール機能を失い、機器内部への塩水浸入ひいては機器内部部品の錆びを招くに至っているものがある。 As described above, according to the conventional steering boot that seals only by the seal portion 103, in a severe environment in which the vehicle is traveling near the coast for a long period of time, the corrosion of the housing 102 of the steering device that is the attachment partner is gradually increased. By damaging the seal part 103, there is a thing that eventually loses the sealing function and leads to the intrusion of salt water into the equipment and the rust of the equipment internal parts.

この塩水浸入の問題は小径側ブーツ取付部においては起きていない。これは、ダイレクトブロー成形やプレスブロー成形などのブーツ内周面を形成するための金型が無いブロー工法において成形される樹脂製ステアリングブーツの場合においても、小径側ブーツ取付部は内外面共に型で形成できるので、内周面側にシール性を良好にさせる工夫ができるからである。これに対し、ブロー成形においてブーツ内周面を形成するための金型を用いることができない大径側ブーツ取付部においては、内周面側にシール性を良好にさせる工夫ができないため、シール性に劣るという問題が本質的に存在する。 This problem of salt water intrusion has not occurred in the small diameter boot mounting portion. This is because, even in the case of a resin steering boot formed by a blow method without a mold for forming the inner peripheral surface of the boot, such as direct blow molding or press blow molding, the small-diameter side boot mounting part is mold on both the inner and outer surfaces. This is because it can be devised to improve the sealing performance on the inner peripheral surface side. On the other hand, in the large-diameter side boot mounting part where a mold for forming the inner peripheral surface of the boot cannot be used in blow molding, since it is not possible to make a good sealing property on the inner peripheral surface side, the sealing property The problem of inferiority exists.

本発明は、大径側ブーツ取付部を経由して機器内部へ塩水が浸入するのを防止する構造のステアリング用ブーツを提供することを目的とする。 It is an object of the present invention to provide a steering boot having a structure that prevents salt water from entering the inside of a device via a large-diameter-side boot mounting portion.

かかる目的を達成するために請求項１記載の発明は、蛇腹部の両端に大径側ブーツ取付部と小径側ブーツ取付部とを有し、大径側ブーツ取付部と小径側ブーツ取付部とをステアリング装置のハウジングとタイロッドとにそれぞれ嵌め込んで、ブーツバンドのみで各ブーツ取付部を締め付けることにより固定されるステアリングブーツにおいて、ハウジングの端部の外周面に環状のフランジが備えられる一方、大径側ブーツ取付部はフランジより内側でハウジングに嵌合されブーツバンドでハウジングに固定されるブーツバンド固定部と、フランジを乗り越えフランジより外側に配置される蛇腹部とブーツバンド固定部とを中継する蛇腹部側端部とを備え、蛇腹部側端部の内周面側にフランジのブーツバンド固定部寄りの縁と全周において当接しこれを圧迫する斜面を設け、かつ斜面を含みフランジを包み込む窪み部を円周上複数カ所に設けるようにしている。 In order to achieve this object, the invention according to claim 1 has a large-diameter side boot mounting portion and a small-diameter side boot mounting portion at both ends of the bellows portion, In a steering boot that is fixed by fitting each into a steering device housing and a tie rod and tightening each boot mounting portion with only a boot band, an annular flange is provided on the outer peripheral surface of the end portion of the housing. The radial side boot mounting part relays between the boot band fixing part fitted to the housing inside the flange and fixed to the housing with the boot band, the bellows part arranged outside the flange over the flange, and the boot band fixing part. With the bellows side end, and the inner periphery of the bellows side end abuts the edge of the flange near the boot band fixing part on the entire circumference It provided a slope to squeeze it, and is in so that providing the recess enclosing the flange includes a slope on the circumference a plurality locations.

さらに、請求項２記載の発明にかかるステアリングブーツは、蛇腹部側端部がブーツバンド固定部よりも径方向外側へ高さＥだけ突出しかつフランジの軸方向長さＢよりも長い軸方向長さＦの段部から成る外周面を有し、かつ蛇腹部側端部の最大外径までの径方向高さＥは下記式１で示す範囲内であり、かつ蛇腹部側端部の軸方向長さＦは下記式２で示す範囲内であると共に、ブロー成形で形成されている。Furthermore, the steering boot according to the second aspect of the invention has an axial length in which the bellows portion side end protrudes radially outward from the boot band fixing portion by a height E and is longer than the axial length B of the flange. A radial height E up to the maximum outer diameter of the bellows portion side end portion having an outer peripheral surface composed of F step portions is within the range represented by the following formula 1, and the axial length of the bellows portion side end portion is The thickness F is within the range represented by the following formula 2 and is formed by blow molding.
Ａ≦Ｅ≦１．５×Ａ …（式１）A ≦ E ≦ 1.5 × A (Formula 1)
Ｂ＋０．８×Ｄ≦Ｆ≦Ｂ＋１．０×Ｄ …（式２）B + 0.8 × D ≦ F ≦ B + 1.0 × D (Formula 2)
ただし、Ａはハウジング外周面からフランジ最大径までの径方向高さ、Where A is the radial height from the outer peripheral surface of the housing to the maximum flange diameter,
Ｂはフランジの軸方向長さ、B is the axial length of the flange,
Ｄはブーツバンド固定部の最大厚さである。D is the maximum thickness of the boot band fixing part.

また、請求項３記載の発明は、蛇腹部の両端に大径側ブーツ取付部と小径側ブーツ取付部とを有し、大径側ブーツ取付部と小径側ブーツ取付部とをステアリング装置のハウジングとタイロッドとにそれぞれ嵌め込んで、ブーツバンドのみで各ブーツ取付部を締め付けることにより固定されるステアリングブーツにおいて、ハウジングの端部の外周面に環状のフランジが備えられる一方、大径側ブーツ取付部はフランジより内側でハウジングに嵌合されブーツバンドでハウジングに固定されるブーツバンド固定部と、フランジを乗り越えフランジより外側に配置される蛇腹部とブーツバンド固定部とを中継する蛇腹部側端部とを備え、蛇腹部側端部の内周面側にフランジのブーツバンド固定部寄りの縁と全周において当接しこれを圧迫する斜面を設け、かつ蛇腹部側端部はブーツバンド固定部よりも径方向外側へ高さＥだけ突出しかつフランジの軸方向長さＢよりも長い軸方向長さＦの段部から成る外周面を有し、かつ蛇腹部側端部の最大外径までの径方向高さＥは下記式１で示す範囲内であり、かつ蛇腹部側端部の軸方向長さＦは下記式２で示す範囲内であると共に、ブロー成形で形成されている。
Ａ≦Ｅ≦１．５×Ａ …（式１）
Ｂ＋０．８×Ｄ≦Ｆ≦Ｂ＋１．０×Ｄ …（式２）
ただし、Ａはハウジング外周面からフランジ最大径までの径方向高さ、
Ｂはフランジの軸方向長さ、
Ｄはブーツバンド固定部の最大厚さである。
また、請求項４記載の発明は、請求項３記載のステアリングブーツにおいて、斜面を含みフランジを包み込む窪み部を円周上全てに設けるようにしている。
また、請求項５記載の発明は、請求項１または４記載のステアリングブーツにおいて、フランジのブーツバンド固定部寄りの縁とブーツバンド固定部とは反対側の縁とが共に角に形成され、窪み部がフランジの前方の角と後方の角の双方に当接しこれを圧迫する軸方向断面形状が曲面形状に形成されると共にフランジの両角に当接していることを特徴としている。 According to a third aspect of the present invention, the bellows portion has a large-diameter boot attachment portion and a small-diameter boot attachment portion at both ends of the bellows portion, and the large-diameter boot attachment portion and the small-diameter boot attachment portion are disposed in the housing of the steering device. In the steering boot that is fitted into the tie rod and fixed by tightening each boot mounting portion only with the boot band, an annular flange is provided on the outer peripheral surface of the end portion of the housing, while the large-diameter boot mounting portion Is a boot band fixing portion that is fitted to the housing and fixed to the housing with a boot band inside the flange, and an end portion on the bellows portion that bridges the bellows portion and the boot band fixing portion that are disposed outside the flange over the flange. A slope that abuts against and presses the edge of the flange band side near the boot band fixing part on the inner peripheral surface side of the bellows part side end. And the bellows portion side end portion has an outer peripheral surface formed of a step portion having an axial length F that protrudes radially outward from the boot band fixing portion by a height E and is longer than the axial length B of the flange. In addition, the radial height E up to the maximum outer diameter of the bellows side end is within the range represented by the following formula 1, and the axial length F of the bellows side end is within the range represented by the following formula 2. In addition, it is formed by blow molding.
A ≦ E ≦ 1.5 × A (Formula 1)
B + 0.8 × D ≦ F ≦ B + 1.0 × D (Formula 2)
Where A is the radial height from the outer peripheral surface of the housing to the maximum flange diameter,
B is the axial length of the flange,
D is the maximum thickness of the boot band fixing part.
According to a fourth aspect of the present invention, in the steering boot according to the third aspect, a recess including an inclined surface and surrounding the flange is provided on the entire circumference .
Further, the inventions of claim 5, wherein a steering boot of claim 1 or 4, wherein the opposite edges are formed on both corners and edges and the boot band fixing portion of the boot band fixing portion side of the flange, An indentation is formed in a curved surface shape in contact with both the front corner and the rear corner of the flange and compresses the recess, and is in contact with both corners of the flange.

請求項１記載のステアリング用ブーツによれば、フランジのブーツバンド固定部寄りの縁と全周において当接しこれを圧迫する斜面を蛇腹部側端部の内周面側に設けるようにしているので、ブーツバンド固定部をフランジより内側に嵌合してブーツバンドでハウジングに固定されると、ブーツバンド固定部におけるシール（面接触）と蛇腹部側端部の斜面とフランジの縁との接触によるシール（線接触）との二重シール構造が構成されることによりシール性が向上する。依って、大径側ブーツ取付部を経由して機器内部へ塩水が浸入するのを防止して相手ハウジングの腐食進行を抑え、塩水の機器内部への浸入を防止できる。 According to the first aspect of the present invention, since the steering boot is provided on the inner peripheral surface side of the bellows portion side end portion with the flange contacting the edge of the boot band fixing portion on the entire circumference and pressing it. When the boot band fixing part is fitted to the inside of the flange and fixed to the housing with the boot band, the seal (surface contact) in the boot band fixing part, the contact between the inclined surface of the bellows part side end and the flange edge A double seal structure with a seal (line contact) is configured, thereby improving the sealing performance. Therefore, it is possible to prevent salt water from entering the inside of the device via the large-diameter boot mounting portion, suppress the progress of corrosion of the counterpart housing, and prevent salt water from entering the device.

また、請求項１記載のステアリング用ブーツは、上述の斜面を含む窪み部を円周上複数カ所に設け、該窪み部でフランジを部分的に包み込むことで蛇腹部側端部の内周面側の斜面をフランジの縁に引きつけた状態でブーツバンド固定部が固定されるようにしているので、蛇腹部側端部の斜面とフランジの縁との接触による線接触で高い面圧が得られ、ブーツバンド固定部におけるシール（面接触）と相俟って二重シール構造を構成し、シール性を向上させる。 Further, the steering boot according to claim 1 is provided with a plurality of recesses including the above-described slope at a plurality of locations on the circumference, and the flange is partially wrapped around the recesses so that the inner peripheral surface side of the bellows portion side end portion is provided. Since the boot band fixing part is fixed in a state where the slope of the flange is attracted to the edge of the flange, a high surface pressure is obtained by line contact by the contact between the slope of the bellows side end and the edge of the flange, Combined with the seal (surface contact) in the boot band fixing part, a double seal structure is formed to improve the sealing performance.

また、請求項４記載のステアリング用ブーツは、上述の斜面を含みフランジを包み込む窪み部を円周上全てに形成しているので、全周域において窪み部とフランジの縁との嵌合（線接触）により高い面圧が得られ、ブーツバンド固定部におけるシール（面接触）と相俟ってシール性が向上する。即ち、窪み部とフランジとが嵌合固定するため、ハウジング外周面に形成されたフランジをブーツが抱き込む（嵌合させる）ことで、ブーツバンド固定部におけるシール（面接触）によるものと、窪み部とフランジとの嵌合によるものとの２段階で固定及びシール機能が付与される。 In the steering boot according to claim 4 , since the depression including the above-described slope and enclosing the flange is formed on the entire circumference, the fitting (line) of the depression and the edge of the flange in the entire circumferential area. High contact pressure is obtained by contact), and the sealing performance is improved in combination with the seal (surface contact) in the boot band fixing portion. That is, since the recess and the flange are fitted and fixed, the boot is held (fitted) by the flange formed on the outer peripheral surface of the housing. The fixing and sealing functions are given in two stages, that is, by fitting the part and the flange.

また、請求項５記載のステアリング用ブーツによれば、フランジのブーツバンド固定部寄りの縁とブーツバンド固定部とは反対側の縁との双方を角に形成すると共に、窪み部をフランジの前方の角と後方の角の双方に当接しこれを圧迫する軸方向断面形状が曲面形状に形成して、フランジの両角に窪み部が食い込ませるため、角と窪み部との接触部の接触圧が高まり、ステアリングブーツの固定が強固なものになる。特に、請求項４記載のステアリング用ブーツのように、窪み部を円周上全てに形成する場合には、窪み部とフランジの双方の角との嵌合（線接触）により高い面圧が得られ、ブーツバンド固定部におけるシール部（面接触）との三重のシール構造により更にシール性が向上する。 According to the steering boot according to claim 5 , both the edge of the flange near the boot band fixing portion and the edge opposite to the boot band fixing portion are formed at the corners, and the recess is formed at the front of the flange. The axial cross-sectional shape that contacts and presses both the corner and the rear corner is formed into a curved shape, and the recesses bite into both corners of the flange, so the contact pressure of the contact portion between the corners and the recesses is The steering boot is fixed more firmly. In particular , as in the case of the steering boot according to claim 4, when the depression is formed on the entire circumference, a high surface pressure is obtained by fitting (line contact) between the depression and both corners of the flange. Further, the sealing performance is further improved by the triple seal structure with the seal portion (surface contact) in the boot band fixing portion.

さらに、請求項２または３記載のステアリングブーツによれば、ブーツ内周面を形成するための金型を使用しなくても、ダイレクトブロー成形やプレスブロー成形などで形成されたステアリングブーツの蛇腹部側端部の内周面に、フランジに最適な嵌合ができる斜面、さらにはフランジと嵌合固定することが可能な窪み部を形成することができる。従来のブーツ構造に因れば、意図した窪み部の形状に形成するにはブーツ内周面を金型により形成する必要があり、必然的に工法が限定される。 Furthermore, according to the steering boot according to claim 2 or 3 , the bellows portion of the steering boot formed by direct blow molding or press blow molding without using a mold for forming the inner peripheral surface of the boot. A slope that can be optimally fitted to the flange, and a recess that can be fitted and fixed to the flange can be formed on the inner peripheral surface of the side end. According to the conventional boot structure, it is necessary to form the inner peripheral surface of the boot with a mold in order to form the intended shape of the recess, and the construction method is inevitably limited.

ここで、ブーツバンド固定部底部から蛇腹部側端部の最大外径までの径方向高さＥがハウジング外周面からフランジ最大径までの径方向高さＡよりも小さい、または蛇腹部側端部の軸方向長さＦが（Ｂ＋０．８×Ｄ）よりも小さいと、窪み部が形成されず、あるいは窪みが形成されても小さ過ぎて、フランジに嵌まることができない。このため、フランジによって、蛇腹部側端部が押し上げられて変形してしまう。これにより、ブーツバンドを固定した場合に蛇腹部側端部とブーツバンド固定部との間に応力が集中し、最悪破断してしまいシール機能を果たさず、機器内部に塩水が浸入し内部部品が錆びてしまう。また、ブーツバンド固定部とハウジング外周面との接触幅が短くなるため、シール機能の低下につながる。 Here, the radial height E from the bottom of the boot band fixing portion to the maximum outer diameter of the bellows side end is smaller than the radial height A from the outer peripheral surface of the housing to the flange maximum diameter, or the bellows side end. If the axial length F is smaller than (B + 0.8 × D), the recess is not formed, or even if the recess is formed, it is too small to fit into the flange. For this reason, the bellows side end is pushed up by the flange and deformed. As a result, when the boot band is fixed, the stress concentrates between the bellows side end and the boot band fixing part, and the worst part breaks and does not perform the sealing function. It will rust. Further, since the contact width between the boot band fixing portion and the outer peripheral surface of the housing is shortened, the sealing function is lowered.

他方、ブーツバンド固定部底部から蛇腹部側端部の最大外径までの径方向高さＥが（１．５×Ａ）よりも大きい、または蛇腹部側端部の軸方向長さＦが（Ｂ＋１．０×Ｄ）よりも大きいと、形成される窪み部が、相手部材のフランジに比べて大きく形成されてしまうため、ステアリングブーツの大径側ブーツ取付部をハウジングに装着した際に、窪み部とフランジとが嵌合せず、又は嵌合力の弱い装着状態となる。このため、従来技術と同様にシール部がシール機能を果たさず、機器内に塩水が浸入し内部部品が錆びてしまう。 On the other hand, the radial height E from the bottom of the boot band fixing portion to the maximum outer diameter of the bellows side end is larger than (1.5 × A), or the axial length F of the bellows side end is ( B + 1.0 × D) is larger than the flange of the mating member. Therefore, when the large-diameter boot mounting portion of the steering boot is mounted on the housing, the depression is formed. The part and the flange do not fit, or the fitting state is weak. For this reason, as in the prior art, the sealing portion does not perform the sealing function, and salt water enters the device and rusts the internal components.

本発明のステアリング用ブーツの一実施形態を示す中央縦断面図であり、窪み部を全周に形成したブーツの例を示す。It is a central longitudinal cross-sectional view which shows one Embodiment of the boot for steering of this invention, and shows the example of the boot which formed the hollow part in the perimeter. 図１のブーツの大径側ブーツ取付部とハウジングとの装着状態を部分的に示す縦断面図である。It is a longitudinal cross-sectional view which shows partially the mounting state of the large diameter side boot attaching part and housing of the boot of FIG. 図２のブーツの装着状態を分解して示す図であり、（Ａ）は大径側ブーツ取付部の縦断面図、（Ｂ）はハウジングのフランジ部分の外観図である。It is a figure which decomposes | disassembles and shows the mounting state of the boot of FIG. 2, (A) is a longitudinal cross-sectional view of a large diameter side boot attaching part, (B) is an external view of the flange part of a housing. 窪み部を円周上数箇所に形成したブーツの大径側ブーツ取付部を示す拡大縦断面図である。It is an expanded longitudinal cross-sectional view which shows the large diameter side boot attaching part of the boot which formed the hollow part in several places on the circumference. 従来のステアリング用ブーツの大径側ブーツ取付部のハウジングへの固定構造の一例を示す中央縦断面図である。It is a center longitudinal cross-sectional view which shows an example of the fixation structure to the housing of the large diameter side boot attaching part of the conventional boot for steering.

以下、本発明の構成を図面に示す実施形態に基づいて詳細に説明する。 Hereinafter, the configuration of the present invention will be described in detail based on embodiments shown in the drawings.

図１に、本発明のステアリング用ブーツの実施形態の一例を示す。この実施形態のステアリングブーツ１は、樹脂製であり、主にブロー成形あるいはインジェクションブロー成形により成形されてなるもので、小径側ブーツ取付部２と大径側ブーツ取付部３との間に蛇腹部４を形成し、この蛇腹部４内にステアリング装置のハウジング５から車幅方向に突出するラックバー６とタイロッド７とを連結するボールジョイント８を収納する一方、両端の大径側ブーツ取付部３及び小径側ブーツ取付部２がステアリング装置のハウジング５とタイロッド７とにそれぞれ嵌め込まれてブーツバンド（図示省略）で締め付けられることにより固定されるものである。 FIG. 1 shows an example of an embodiment of a steering boot according to the present invention. The steering boot 1 of this embodiment is made of resin and is mainly formed by blow molding or injection blow molding, and has a bellows portion between the small diameter side boot mounting portion 2 and the large diameter side boot mounting portion 3. 4, and a ball joint 8 for connecting the rack bar 6 protruding from the housing 5 of the steering device in the vehicle width direction and the tie rod 7 is accommodated in the bellows portion 4, while the large-diameter boot mounting portions 3 at both ends are accommodated. The small-diameter boot mounting portion 2 is fixed by being fitted into the housing 5 and the tie rod 7 of the steering device and tightened with a boot band (not shown).

ここで、大径側ブーツ取付部３は、図２及び図３に示すように、ハウジング５の端部の外周面に備えられた環状のフランジ９の内側でハウジング５に嵌合されブーツバンド１４でハウジング５に固定されるブーツバンド固定部１０と、フランジ９を乗り越えフランジ９より外側に配置される蛇腹部４とブーツバンド固定部１０とを中継する蛇腹部側端部１１とを備え、蛇腹部側端部１１の内周面側にフランジ９のブーツバンド固定部寄りの縁（以下、内側の縁と呼ぶ）９ciと全周において当接しこれを圧迫する斜面１２を少なくとも設けるようにしている。尚、本明細書において、大径側ブーツ取付部の蛇腹部側端部１１は、図３に示すように、ブーツバンド固定部１０の蛇腹部側の端Ｇから蛇腹部側端部１１と蛇腹部４との境界部Ｈまでの間の領域を意味するものであり、その内周面に窪み部１３を形成し、窪み部１３は、ステアリング装置のハウジング５の外周面に形成されたフランジ９と嵌合する。また、ブーツバンド固定部１０は、径方向外側に広がった蛇腹部側端部１１と開口部１５との間で相対的に凹んだ溝形を成し、ブーツバンド１４の位置決めと抜け止めを容易にするように設けられている。 Here, as shown in FIGS. 2 and 3, the large-diameter boot mounting portion 3 is fitted into the housing 5 inside the annular flange 9 provided on the outer peripheral surface of the end portion of the housing 5, and the boot band 14. A boot band fixing portion 10 fixed to the housing 5, a bellows portion 4 disposed over the flange 9 and outside the flange 9, and a bellows portion side end portion 11 relaying the boot band fixing portion 10. At least an inclined surface 12 that abuts and presses the edge 9ci of the flange 9 near the boot band fixing portion (hereinafter referred to as an inner edge) 9ci on the entire circumference is provided on the inner peripheral surface side of the portion side end portion 11. . In this specification, the bellows portion side end portion 11 of the large-diameter side boot mounting portion is connected to the bellows portion side end portion 11 from the bellows portion side end G of the bootband fixing portion 10 as shown in FIG. This means a region between the portion 4 and the boundary portion H, and a recess portion 13 is formed on the inner peripheral surface thereof. The recess portion 13 is a flange 9 formed on the outer peripheral surface of the housing 5 of the steering device. Mates with. Moreover, the boot band fixing | fixed part 10 comprises the groove | channel shape which was dented relatively between the bellows part side edge part 11 and the opening part 15 which spread on the radial direction outer side, and positioning and retaining of the boot band 14 are easy. It is provided to be.

他方、本実施形態におけるハウジング５のフランジ９は、図２及び図３（Ｂ）に示すように、ブーツバンド固定部寄りの縁即ち内側の縁９ciとブーツバンド固定部１０とは反対側の縁（以下、外側の縁と呼ぶ）９coとが共に角に形成されている。勿論、フランジ９の形状はこれに限られるものではなく、少なくとも蛇腹部側端部１１の内周面側の斜面１２とブーツバンド固定部寄りの内側の縁９ciとが全周において当接しこれを圧迫するすることができるものであれば足り、フランジ９のブーツバンド固定部寄りの内側の縁９ciが曲面であったり、角取りが施された面であっても良い。しかし、好ましくは少なくとも内側の縁９ciが角に形成されていることであり、この場合にはフランジ９の内側の縁９ciが蛇腹部側端部１１の内周面側の斜面１２に食い込むことにより接触圧力（接触面圧）が高まり、高いシール性が得られる。 On the other hand, as shown in FIGS. 2 and 3B, the flange 9 of the housing 5 in this embodiment has an edge closer to the boot band fixing portion, that is, an inner edge 9ci and an edge opposite to the boot band fixing portion 10. 9co (hereinafter referred to as the outer edge) are formed at the corners. Of course, the shape of the flange 9 is not limited to this, and at least the inclined surface 12 on the inner peripheral surface side of the bellows portion side end portion 11 and the inner edge 9ci near the boot band fixing portion abut on the entire periphery. It is sufficient if it can be pressed, and the inner edge 9ci of the flange 9 near the boot band fixing portion may be a curved surface or a chamfered surface. However, it is preferable that at least the inner edge 9ci is formed at a corner. In this case, the inner edge 9ci of the flange 9 bites into the inclined surface 12 on the inner peripheral surface side of the bellows portion side end portion 11. Contact pressure (contact surface pressure) increases, and high sealing performance is obtained.

蛇腹部側端部１１の内周面側においては、少なくとも斜面１２の部分でハウジング５のフランジ９の内側の縁９ciを圧迫して、斜面１２とフランジ９の内側の縁９ciとの間でシールを構成する構造とすれば良い。同時に、蛇腹部側端部１１がフランジ９に乗り上げることによって径方向外側へ強く押される力が生ずると、蛇腹部側端部１１とブーツバンド固定部１０との境界部分に応力が集中して破断してしまったり、ブーツバンド固定部１０とハウジング５の外周面との接触幅即ちシール部の幅を短くしてシール機能を低下させたりする虞があるので、フランジ９の内側の縁９ci及び必要に応じて外側の縁９coに食い込むように嵌合する部分を除いて、蛇腹部側端部１１の内周面と必要以上に強く接触しないようにすることが望ましい。つまり、蛇腹部側端部１１とブーツバンド固定部１０とは、例えば図４（Ａ）の上半分に示すような径の異なる段違いの円筒から成る単純な構造とし、それらの間の境界部分を斜面１２にして、ハウジング５側のフランジ９の内側の縁９ciと全周において当接させかつ圧迫するようにしても良い。 On the inner peripheral surface side of the bellows portion side end portion 11, the inner edge 9 ci of the flange 9 of the housing 5 is pressed at least at the portion of the inclined surface 12, and a seal is formed between the inclined surface 12 and the inner edge 9 ci of the flange 9. It is sufficient to adopt a structure that constitutes. At the same time, when a force that strongly pushes the outer side in the radial direction is generated by riding the bellows portion side end portion 11 on the flange 9, stress concentrates on the boundary portion between the bellows portion side end portion 11 and the bootband fixing portion 10 and breaks. Or the contact width between the boot band fixing portion 10 and the outer peripheral surface of the housing 5, that is, the width of the seal portion may be shortened to lower the sealing function. Accordingly, it is desirable not to contact the inner peripheral surface of the bellows portion side end portion 11 more strongly than necessary except for a portion that fits into the outer edge 9co. In other words, the bellows portion side end portion 11 and the boot band fixing portion 10 have a simple structure composed of cylinders with different diameters, for example, as shown in the upper half of FIG. The inclined surface 12 may be brought into contact with and pressed against the inner edge 9ci of the flange 9 on the housing 5 side.

また、蛇腹部側端部１１の内周面側には、斜面１２を設けるだけでなく、場合によっては斜面１２を含みフランジ９を包み込む窪み部１３を図１に示すように円周上全てに、あるいは図４に示すように円周上複数カ所に設けることが好ましい。図１に示す実施形態のステアリング用ブーツ１の場合、軸方向断面が曲面形状（Ｒ形状）に形成された窪み部１３を全周に亘って形成するとともにフランジの内側の縁９ciと外側の縁９coとの双方を角に形成することで、フランジ９をブーツが抱き込むように嵌合させて、内側の縁９ciと外側の縁９coとの双方の角を窪み部１３に食い込ませるように線接触させている。これによって、内側の縁９ciと外側の縁９coとの双方の角と窪み部１３との接触部分での接触圧力（接触面圧）が高まり、ステアリングブーツ１の固定が強固なものになると共に、ブーツバンド固定部１０におけるシール部（面接触）と相俟って三重のシール構造を形成し、更にシール性を向上させることとなる。本実施形態においては、蛇腹部側端部１１の内周面側の斜面１２は、蛇腹部側端部１１の内周面側を凹ませることにより軸方向断面形状が曲面形状に形成される窪み部１３の一部によって構成されている。 Further, not only the inclined surface 12 is provided on the inner peripheral surface side of the bellows portion side end portion 11, but in some cases, the recessed portion 13 that includes the inclined surface 12 and encloses the flange 9 is provided on the entire circumference as shown in FIG. Alternatively, as shown in FIG. 4, it is preferably provided at a plurality of locations on the circumference. In the case of the steering boot 1 according to the embodiment shown in FIG. 1, a recess 13 having an axial cross section formed in a curved surface shape (R shape) is formed over the entire circumference, and an inner edge 9ci and an outer edge of the flange are formed. By forming both sides with 9co at the corners, the flange 9 is fitted so that the boot can be embraced so that the corners of both the inner edge 9ci and the outer edge 9co bite into the recess 13. It is in contact. As a result, the contact pressure (contact surface pressure) at the contact portion between the corners of both the inner edge 9ci and the outer edge 9co and the recess 13 is increased, and the steering boot 1 is firmly fixed. Combined with the seal part (surface contact) in the boot band fixing part 10, a triple seal structure is formed, and the sealing performance is further improved. In the present embodiment, the inclined surface 12 on the inner peripheral surface side of the bellows portion side end portion 11 is a depression whose axial cross-sectional shape is formed into a curved shape by denting the inner peripheral surface side of the bellows portion side end portion 11. It is constituted by a part of the part 13.

また、図４に示す実施形態のステアリング用ブーツ１の場合には、軸方向断面が曲面形状（Ｒ形状）に形成された窪み部１３が円周上数箇所に形成されている。本実施形態の場合、図４（Ｂ）に示すように、円筒状を成す蛇腹部側端部１１の一部を径方向内側へ向けて凹ませるように突出させることにより、前部側即ちフランジ９の外側の縁９co側を包み込むように変形させて、蛇腹部側端部１１の円周方向全域に連続的に形成された内周面側の斜面１２との間で９０°置きに４箇所の窪み部１３を形成するようにしている。この場合には、窪み部１３の前部側、即ちフランジ９の外側の縁９coと嵌合する部分でフランジ９を抱え込むように拘束できるので、ブーツ固定部１０並びに蛇腹部側端部１１の内周面側の斜面１２部分をフランジの内側の縁９ci側へ引き寄せる力が付与され、斜面１２とフランジの内側の縁９ciの角との間のシール性を損なうことが少なくなる。この場合においても、斜面１２とフランジの内側の縁９ciとの間で高い面圧が得られ、ブーツバンド固定部におけるシール部と相俟って二重シール構造を構成し、シール性を向上させることができる。 Further, in the case of the steering boot 1 according to the embodiment shown in FIG. 4, depressions 13 having an axial cross section formed in a curved surface shape (R shape) are formed in several places on the circumference. In the case of the present embodiment, as shown in FIG. 4B, a part of the cylindrical bellows portion side end portion 11 is protruded so as to be recessed radially inward, so that the front side, that is, the flange is formed. 9 is deformed so as to wrap around the outer edge 9co side, and is provided at intervals of 90 ° with the inclined surface 12 on the inner peripheral surface side continuously formed in the entire circumferential direction of the bellows portion side end portion 11. The hollow portion 13 is formed. In this case, since the flange 9 can be restrained so as to be held in the front portion side of the hollow portion 13, that is, the portion fitted to the outer edge 9co of the flange 9, the inside of the boot fixing portion 10 and the bellows portion side end portion 11. A force that draws the inclined surface 12 portion on the peripheral surface side toward the inner edge 9ci of the flange is applied, and the sealing performance between the inclined surface 12 and the corner of the inner edge 9ci of the flange is reduced. Even in this case, a high surface pressure is obtained between the inclined surface 12 and the inner edge 9ci of the flange, and a double seal structure is formed in combination with the seal portion in the boot band fixing portion, thereby improving the sealing performance. be able to.

このステアリング用ブーツ１を成形する工法としては、特にブロー成形に限られるものではないが、ブロー成形によることが好ましい。しかしながら、ダイレクトブロー成形やプレスブロー成形などのブーツ内周面を形成するための金型が無いブロー成形の場合、大径側ブーツ取付部３を成形する際に、斜面１２を含めて窪み部１３を意図した形状に形成することは難しい。一方、ブロー成形によるブーツの内周面の形状は外型によって形成される外周面の形状に影響を受ける。そこで、本実施形態にかかるステアリングブーツ１の蛇腹部側端部１１は、開き型から成る外型によって、ハウジング５の端部外周面に形成されているフランジ９の形状とほぼ相似形状でかつブーツバンド固定部１０よりも径方向外側へ高さＥだけ突出しかつ軸方向長さＦを有する段部から成る外周面を形成するように外側の面が象られる。また、窪み部１３が円周上数箇所に成形される実施形態の場合、全体としてブーツバンド固定部１０よりも径方向外側へ高さＥだけ突出しかつ軸方向長さＦを有する円筒状を成す段部を形成すると共に、窪み部１３が形成される箇所に対応する位置のみが、ハウジング５の端部外周面に形成されているフランジ９の形状とほぼ相似形状となるように蛇腹部側端部１１の一部を径方向内側へ向けて凹ませるように突出させるように外型によって外側の面が象られる。これにより、全体として円筒状を成す蛇腹部側端部１１の一部をフランジ９の外側の縁９co側を包み込むように変形させて、蛇腹部側端部１１の円周方向全域に連続的に形成された内周面側の斜面１２との間で９０°置きに４箇所の窪み部１３を形成するようにしている。 The method for forming the steering boot 1 is not particularly limited to blow molding, but blow molding is preferred. However, in the case of blow molding without a mold for forming the inner peripheral surface of the boot such as direct blow molding or press blow molding, when forming the large-diameter side boot mounting portion 3, the recess portion 13 including the slope 12 is included. It is difficult to form the desired shape. On the other hand, the shape of the inner peripheral surface of the boot by blow molding is affected by the shape of the outer peripheral surface formed by the outer mold. Therefore, the bellows portion side end portion 11 of the steering boot 1 according to the present embodiment has a shape that is substantially similar to the shape of the flange 9 formed on the outer peripheral surface of the end portion of the housing 5 by an outer die that is an open die. An outer surface is formed so as to form an outer peripheral surface formed of a step portion that protrudes by a height E outward in the radial direction from the band fixing portion 10 and has an axial length F. Further, in the case of the embodiment in which the depression 13 is formed at several places on the circumference, as a whole, it forms a cylindrical shape that protrudes by a height E outward in the radial direction from the boot band fixing portion 10 and has an axial length F. The bellows portion side end is formed so that only the position corresponding to the position where the recess portion 13 is formed is substantially similar to the shape of the flange 9 formed on the outer peripheral surface of the end portion of the housing 5 while forming the stepped portion. An outer surface is formed by the outer mold so that a part of the portion 11 protrudes so as to be recessed inward in the radial direction. As a result, a part of the bellows portion side end portion 11 having a cylindrical shape as a whole is deformed so as to wrap around the outer edge 9co side of the flange 9, and continuously in the entire circumferential direction of the bellows portion side end portion 11. Four recesses 13 are formed at intervals of 90 ° with the formed inclined surface 12 on the inner peripheral surface side.

ここで、外型によって象られる蛇腹部側端部１１の最大外径までの径方向高さＥは下記式１で示す範囲内であり、かつ蛇腹部側端部１１の軸方向長さＦは下記式２で示す範囲内に設定されれば、蛇腹部側端部１１の内周面側にフランジ９の内側の縁９ciの角と全周において当接しこれを圧迫する斜面１２を含む軸方向断面形状が曲面形状の窪み部１３がブロー成形によって全周に形成できる。
Ａ≦Ｅ≦１．５×Ａ …（式１）
Ｂ＋０．８×Ｄ≦Ｆ≦Ｂ＋１．０×Ｄ …（式２）
ただし、Ａはハウジング外周面からフランジ最大径までの径方向高さ、
Ｂはフランジの軸方向長さ、
Ｄはブーツバンド固定部の最大厚さである。 Here, the radial height E up to the maximum outer diameter of the bellows-side end 11 formed by the outer mold is within the range represented by the following formula 1, and the axial length F of the bellows-side end 11 is: If it is set within the range shown by the following formula 2, the axial direction including the inclined surface 12 that abuts on the inner peripheral surface side of the bellows portion side end portion 11 with the corner of the inner edge 9ci of the flange 9 and presses the corner 9ci. The depression 13 having a curved cross section can be formed on the entire circumference by blow molding.
A ≦ E ≦ 1.5 × A (Formula 1)
B + 0.8 × D ≦ F ≦ B + 1.0 × D (Formula 2)
Where A is the radial height from the outer peripheral surface of the housing to the maximum flange diameter,
B is the axial length of the flange,
D is the maximum thickness of the boot band fixing part.

ここで、蛇腹部側端部１１の外周面の輪郭形状がハウジング側のフランジとほぼ相似形状とされている場合には、フランジ９の内側の縁９ciの角のみならず外側の縁９coの角にも当接しこれを圧迫する斜面１２を有する軸方向断面がＲ形状の窪み部１３がブロー成形によっても容易に成形される。 Here, when the contour shape of the outer peripheral surface of the bellows portion side end portion 11 is substantially similar to the flange on the housing side, not only the corner of the inner edge 9ci of the flange 9 but also the corner of the outer edge 9co. In addition, the recess 13 having an R-shaped cross section in the axial direction and having the inclined surface 12 that contacts and presses is also easily formed by blow molding.

蛇腹部側端部１１は必ずしもハウジング５の端部外周面に形成されているフランジ９の形状とほぼ相似形状に外周面が形成される必要はない。蛇腹部側端部１１は、少なくとも、ブーツバンド固定部１０よりも径方向外側へ高さＥだけ突出しかつ軸方向長さＦを有する段部を構成する外周面を有していれば足りる。フランジ９の高さＡと長さＢよりも大きな段部を形成すれば、窪み部１３を内周面側に形成できる。 The outer peripheral surface of the bellows portion side end portion 11 does not necessarily have a shape substantially similar to the shape of the flange 9 formed on the outer peripheral surface of the end portion of the housing 5. The bellows portion side end portion 11 only needs to have at least an outer peripheral surface that forms a step portion that protrudes by a height E outward in the radial direction from the boot band fixing portion 10 and has an axial length F. If a step portion larger than the height A and the length B of the flange 9 is formed, the recessed portion 13 can be formed on the inner peripheral surface side.

なお、上述の形態は本発明の好適な形態の一例ではあるがこれに限定されるものではなく本発明の要旨を逸脱しない範囲において種々変形実施可能である。例えば、上述の実施形態では、ブロー成形により製作されることを前提にした大径側ブーツ取付部３の蛇腹部側端部１１の外形状並びに寸法関係について主に説明しているが、これに特に限定されるものではなく、スライド中子などを用いて小径側ブーツ取付部と同様に大径側ブーツ取付部３を内外面共に型で形成する場合には、上述の式１及び式２を満たす寸法・形状の蛇腹部側端部１１を外型（開き型）で形成しなくとも、蛇腹部側端部１１及びブーツバンド固定部１０を含めた大径側ブーツ取付部３の内周面側の形状・寸法は中子と外型との間で斜面１２と共に形成される。 The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the outer shape and the dimensional relationship of the bellows portion side end portion 11 of the large-diameter side boot mounting portion 3 on the assumption that it is manufactured by blow molding are mainly described. There is no particular limitation, and when the large-diameter side boot mounting portion 3 is formed with a mold on both the inner and outer surfaces using a slide core or the like, the above formulas 1 and 2 are The inner peripheral surface of the large-diameter side boot mounting portion 3 including the bellows portion side end portion 11 and the boot band fixing portion 10 without forming the bellows portion side end portion 11 of the size and shape to be filled with an outer mold (opening type). The shape and dimensions of the side are formed with the inclined surface 12 between the core and the outer mold.

（実施例１）
表１に示す条件で、窪み部１３を円周上数箇所に形成している図４のステアリングブーツ１に対して、塩水噴霧（サイクル）試験を行なった。試験は、蛇腹部側端部の軸方向長さ（Ｆ）が３．７ｍｍ〜４．５ｍｍまでの間で０．１ｍｍ間隔の９段階と、ブーツバンド固定部底部から蛇腹部側端部の最大外径までの径方向高さ（Ｅ）が０．６ｍｍ〜１．３ｍｍまでの間で０．１ｍｍ間隔の８段階とで、７２通りの組み合わせについて、窪み部１３の形成の有無と腐食度合いについて寸法別に求めた。ここで、試験で使用したステアリングブーツ１は、ハウジング外周面からフランジ最大径までの径方向高さ（Ａ）が０．７５ｍｍ、フランジの軸方向長さ（Ｂ）が２．５ｍｍ、ブーツバンド固定部の最大ゴム厚さ（Ｄ）が１．７５ｍｍのダイレクトブロー成形で作成された樹脂製である。このステアリングブーツ（ｎ＝５）をステアリング装置に装着した状態で、密封機器（塩水噴霧（サイクル）試験機）内に設置し、以下の工程を１５０サイクル（１２００ｈ）で試験を行なった。 Example 1
Under the conditions shown in Table 1, a salt spray (cycle) test was performed on the steering boot 1 of FIG. 4 in which the recessed portions 13 were formed at several places on the circumference. The test consists of 9 steps with an axial length (F) of the bellows side end portion of 3.7 mm to 4.5 mm at intervals of 0.1 mm, and the maximum from the bottom of the boot band fixing portion to the bellows side end portion. About the presence / absence of the depression 13 and the degree of corrosion for 72 combinations of the radial height (E) up to the outer diameter between 0.6 mm and 1.3 mm and 8 steps at intervals of 0.1 mm. Obtained by dimension. Here, the steering boot 1 used in the test has a radial height (A) from the outer peripheral surface of the housing to the flange maximum diameter of 0.75 mm, an axial length of the flange (B) of 2.5 mm, and a boot band fixed. It is made of resin made by direct blow molding with a maximum rubber thickness (D) of 1.75 mm. With this steering boot (n = 5) mounted on the steering device, it was installed in a sealed device (salt spray (cycle) test machine), and the following steps were tested in 150 cycles (1200 h).

（試験結果）
試験結果を表２に示す。

ただし、表２中の試験結果の「腐食度合」の定義については以下の通りである。
○：全てのブーツが機器内部への塩水浸入を防止することができた。
△：少なくとも一つのブーツは機器内部への塩水浸入を防止することができた。
×：全てのブーツが機器内部への塩水浸入を防止することができなかった。 (Test results)
The test results are shown in Table 2.

However, the definition of “corrosion degree” in the test results in Table 2 is as follows.
○: All boots were able to prevent salt water from entering the equipment.
(Triangle | delta): At least 1 boot was able to prevent the salt water penetration | invasion inside an apparatus.
X: All the boots could not prevent salt water from entering the apparatus.

表２より、（Ｆ）が３．９〜４．２ｍｍ、（Ｅ）が０．８〜１．１ｍｍの範囲のステアリングブーツだと、窪み部１３がフランジ９の両端に食い込むように嵌合固定されるので、シール性を確保できた。そのため、機器内部への塩水の浸入を防止できた。 According to Table 2, when (F) is a steering boot in the range of 3.9 to 4.2 mm and (E) is in the range of 0.8 to 1.1 mm, the recessed portion 13 is fitted and fixed so as to bite into both ends of the flange 9. As a result, the sealing performance can be secured. Therefore, it was possible to prevent salt water from entering the equipment.

（実施例２）
表３に示す条件で、窪み部１３を円周上数箇所に形成した図４のステアリングブーツ１に対して、塩水噴霧（サイクル）試験を行なった。試験は、蛇腹部側端部の軸方向長さ（Ｆ）が４．０ｍｍ〜４．８ｍｍまでの間で０．１ｍｍ間隔の９段階、ブーツバンド固定部底部から蛇腹部側端部の最大外径までの径方向高さ（Ｅ）が０．７ｍｍ〜１．４ｍｍまでの間で０．１ｍｍ間隔の８段階の７２通りの組み合わせについて、窪み部１３の形成の有無と腐食度合いについて寸法別に求めた。ここで、試験で使用したステアリングブーツは、ハウジング外周面からフランジ最大径までの径方向高さ（Ａ）が０．９ｍｍ、フランジの軸方向長さ（Ｂ）が２．８ｍｍ、ブーツバンド固定部の最大ゴム厚さ（Ｄ）が１．７５ｍｍのダイレクトブロー成形で作成された樹脂製である。このステアリングブーツ（ｎ＝５）をステアリング装置に装着した状態で、密封機器（塩水噴霧（サイクル）試験機）内に設置し、以下の工程を１５０サイクル（１２００ｈ）で試験を行なった。 (Example 2)
Under the conditions shown in Table 3, a salt spray (cycle) test was performed on the steering boot 1 of FIG. 4 in which the depressions 13 were formed at several places on the circumference. The test was performed in 9 stages with an axial length (F) of the bellows side end portion of 4.0 mm to 4.8 mm at 0.1 mm intervals, from the bottom of the boot band fixing portion to the maximum outside of the bellows side end portion. With respect to 72 combinations of eight stages with a radial height (E) ranging from 0.7 mm to 1.4 mm at intervals of 0.1 mm, the presence / absence of formation of the depressions 13 and the degree of corrosion are determined for each dimension. It was. Here, the steering boot used in the test has a radial height (A) from the outer peripheral surface of the housing to the flange maximum diameter of 0.9 mm, an axial length of the flange (B) of 2.8 mm, and a boot band fixing portion. The maximum rubber thickness (D) is a resin made by direct blow molding with 1.75 mm. With this steering boot (n = 5) mounted on the steering device, it was installed in a sealed device (salt spray (cycle) test machine), and the following steps were tested in 150 cycles (1200 h).

（試験結果）
試験結果を表４に示す。表４より、（Ｆ）が４．２〜４．５ｍｍ、（Ｅ）が０．９〜１．３ｍｍとの範囲のステアリングブーツだと、窪み部１３がフランジ９の内側の縁９ciと外側の縁９coとの双方の角に食い込むように嵌合固定されるので、シール性を確保できた。そのため、機器内部への塩水の浸入を防止できた。 (Test results)
The test results are shown in Table 4. According to Table 4, when the steering boot is in the range of (F) 4.2 to 4.5 mm and (E) 0.9 to 1.3 mm, the recess 13 is formed on the inner edge 9ci of the flange 9 and the outer edge. Since it is fitted and fixed so as to bite into both corners with the edge 9co, the sealing property can be secured. Therefore, it was possible to prevent salt water from entering the equipment.

ただし、表４中の試験結果の「腐食度合」の定義については以下の通りである。
○：全てのブーツが機器内部への塩水浸入を防止することができた。
△：少なくとも一つのブーツは機器内部への塩水浸入を防止することができた。
×：全てのブーツが機器内部への塩水浸入を防止することができなかった。

However, the definition of “corrosion degree” in the test results in Table 4 is as follows.
○: All boots were able to prevent salt water from entering the equipment.
(Triangle | delta): At least 1 boot was able to prevent the salt water penetration | invasion inside an apparatus.
X: All the boots could not prevent salt water from entering the apparatus.

以上の実施例１、２の両結果を満たす式を導出すると、以下の（１）式、（２）式のようになる。
Ａ≦Ｅ≦１．５×Ａ …（１）
Ｂ＋０．８×Ｄ≦Ｆ≦Ｂ＋１．０×Ｄ …（２）
そこで、蛇腹部側端部１１の最大外径までの径方向高さ（Ｅ）の範囲が式１を満たし、蛇腹部側端部の軸方向長さ（Ｆ）の範囲が式２を満たす場合には、ブーツ内周面を形成するための金型を使用しなくても、ダイレクトブロー成形で形成されたステアリングブーツの蛇腹部側端部１１の内周面に、フランジ９に最適な嵌合ができる窪み部１３を形成することができた。 Deriving equations satisfying both the results of Examples 1 and 2 above, the following equations (1) and (2) are obtained.
A ≦ E ≦ 1.5 × A (1)
B + 0.8 × D ≦ F ≦ B + 1.0 × D (2)
Therefore, the range of the radial height (E) up to the maximum outer diameter of the bellows portion side end portion 11 satisfies the formula 1, and the range of the axial length (F) of the bellows portion side end portion satisfies the formula 2. The flange 9 is optimally fitted to the inner peripheral surface of the bellows side end portion 11 of the steering boot formed by direct blow molding without using a mold for forming the inner peripheral surface of the boot. The hollow part 13 which can be formed was able to be formed.

その反面、上記式１及び式２の範囲から外れると、以下のような不具合が発生してしまう。ＥがＡよりも小さい、又は、ＦがＢ＋０．８×Ｄよりも小さいと、窪み部１３が形成されず（または窪み部１３が小さ過ぎて）、フランジ９に嵌まることができないことにより、フランジ９によって、蛇腹部側端部１１が押し上げられて変形してしまった。このため、ブーツバンド１４を固定した場合に蛇腹部側端部１１とブーツバンド固定部１０との境界部分に応力が集中し、最悪破断してしまいシール機能を果たさず、機器内部に塩水が浸入し内部部品が錆びてしまった。また、ブーツバンド固定部１０とハウジング５の外周面との接触幅即ちシール部の幅が短くなるため、シール機能の低下につながった。 On the other hand, if it deviates from the range of the above formulas 1 and 2, the following problems occur. When E is smaller than A or F is smaller than B + 0.8 × D, the recess 13 is not formed (or the recess 13 is too small) and cannot fit into the flange 9. The bellows portion side end portion 11 is pushed up by the flange 9 and deformed. For this reason, when the boot band 14 is fixed, stress concentrates on the boundary portion between the bellows portion side end 11 and the boot band fixing portion 10, and the worst breakage occurs, so that the sealing function is not performed and salt water enters the inside of the device. However, the internal parts rusted. Further, since the contact width between the boot band fixing portion 10 and the outer peripheral surface of the housing 5, that is, the width of the seal portion is shortened, the sealing function is lowered.

他方、Ｅが１．５×Ａよりも大きい、又は、ＦがＢ＋１．０×Ｄよりも大きいと、形成される窪み部１３が、相手部材たるフランジ９に比べて大きく形成されてしまう為、ステアリングブーツ１の大径側ブーツ取付部３をハウジング５に装着した際に、フランジ９の内側の縁９ciと外側の縁９coとの双方の角が蛇腹部側端部１１の窪み部１３に食い込むように嵌合できず、又は嵌合力の弱い装着状態となる為、従来技術と同様にブーツバンド固定部１０とハウジング５の外周面との接触部・シール部がシール機能を果たさなくなった時に、機器内に塩水が浸入し内部部品が錆びてしまった。 On the other hand, if E is larger than 1.5 × A or F is larger than B + 1.0 × D, the formed recess 13 is formed larger than the flange 9 which is the counterpart member. When the large-diameter side boot mounting portion 3 of the steering boot 1 is mounted on the housing 5, both corners of the inner edge 9ci and the outer edge 9co of the flange 9 bite into the hollow portion 13 of the bellows portion side end portion 11. When the contact part / seal part between the boot band fixing part 10 and the outer peripheral surface of the housing 5 does not perform the sealing function as in the conventional technique, the fitting state cannot be fitted or the fitting force is weak. Salt water entered the equipment and the internal parts rusted.

１ステアリングブーツ
２小径側ブーツ取付部
３大径側ブーツ取付部
４蛇腹部
５ハウジング
７タイロッド
９フランジ
９ci フランジのブーツバンド固定部寄りの縁（フランジ内側の縁）
９co フランジのブーツバンド固定部とは反対側の縁（フランジ外側の縁）
１０ブーツバンド固定部
１１蛇腹部側端部
１２蛇腹部側端部の内周面側の斜面
１３窪み部 DESCRIPTION OF SYMBOLS 1 Steering boot 2 Small-diameter side boot attachment part 3 Large-diameter side boot attachment part 4 Bellows part 5 Housing 7 Tie rod 9 Flange 9ci Edge of boot band fixing part of flange (edge inside flange)
Edge of the 9co flange opposite to the boot band fixing part (edge outside the flange)
DESCRIPTION OF SYMBOLS 10 Boot band fixing | fixed part 11 Bellows part side edge part 12 Slope of inner peripheral surface side of bellows part side edge part 13 Indentation part

Claims

There are a large-diameter side boot mounting portion and a small-diameter side boot mounting portion at both ends of the bellows portion, and the large-diameter side boot mounting portion and the small-diameter side boot mounting portion are respectively fitted into the housing and the tie rod of the steering device, In the steering boot fixed by tightening each boot mounting part only with the boot band,
While the outer peripheral surface of the end of the housing is provided with an annular flange,
The large-diameter side boot mounting portion is fitted to the housing inside the flange and fixed to the housing with the boot band, and a bellows portion that goes over the flange and is arranged outside the flange. A bellows portion side end relaying the boot band fixing portion;
Provided on the inner peripheral surface side of the bellows portion side end portion is an inclined surface that contacts and presses the edge of the flange near the boot band fixing portion on the entire circumference ; and
A steering boot comprising a plurality of recesses on the circumference including the slope and enclosing the flange .

The end portion on the bellows portion side has an outer peripheral surface that includes a stepped portion having an axial length F that protrudes radially outward from the boot band fixing portion by a height E and is longer than the axial length B of the flange. The radial height E up to the maximum outer diameter of the bellows side end is within the range represented by the following formula 1, and the axial length F of the bellows side end is the range represented by the following formula 2. The steering boot according to claim 1, wherein the steering boot is formed by blow molding .
A ≦ E ≦ 1.5 × A (Formula 1)
B + 0.8 × D ≦ F ≦ B + 1.0 × D (Formula 2)
Where A is the radial height from the outer peripheral surface of the housing to the maximum flange diameter,
B is the axial length of the flange,
D is the maximum thickness of the boot band fixing part.

There are a large-diameter side boot mounting portion and a small-diameter side boot mounting portion at both ends of the bellows portion, and the large-diameter side boot mounting portion and the small-diameter side boot mounting portion are respectively fitted into the housing and the tie rod of the steering device, In the steering boot fixed by tightening each boot mounting part only with the boot band,
  While the outer peripheral surface of the end of the housing is provided with an annular flange,
  The large-diameter side boot mounting portion is fitted to the housing inside the flange and fixed to the housing with the boot band, and a bellows portion that goes over the flange and is arranged outside the flange. A bellows portion side end relaying the boot band fixing portion;
  Provided on the inner peripheral surface side of the bellows portion side end portion is an inclined surface that contacts and presses the edge of the flange near the boot band fixing portion on the entire circumference; and
  The end portion on the bellows portion side has an outer peripheral surface that includes a stepped portion having an axial length F that protrudes radially outward from the boot band fixing portion by a height E and is longer than the axial length B of the flange. The radial height E up to the maximum outer diameter of the bellows side end is within the range represented by the following formula 1, and the axial length F of the bellows side end is the range represented by the following formula 2. A steering boot characterized by being formed by blow molding.
A ≦ E ≦ 1.5 × A (Formula 1)
B + 0.8 × D ≦ F ≦ B + 1.0 × D (Formula 2)
Where A is the radial height from the outer peripheral surface of the housing to the maximum flange diameter,
B is the axial length of the flange,
D is the maximum thickness of the boot band fixing part.

The steering boot according to claim 3, wherein a recess including the slope and enclosing the flange is provided on the entire circumference .

The flange has an edge near the boot band fixing portion and an edge on the opposite side of the boot band fixing portion at the corners, and the recessed portion hits both the front corner and the rear corner of the flange. 5. The steering boot according to claim 1, wherein an axial cross-sectional shape that comes into contact with and presses is formed in a curved surface shape and is in contact with both corners of the flange .